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Sample records for cemented waste products

  1. Use of Incineration Solid Waste Bottom Ash as Cement Mixture in Cement Production

    Science.gov (United States)

    Jun, N. H.; Abdullah, M. M. A. B.; Jin, T. S.; Kadir, A. A.; Tugui, C. A.; Sandu, A. V.

    2017-06-01

    Incineration solid waste bottom ash was use to examine the suitability as a substitution in cement production. This study enveloped an innovative technology option for designing new equivalent cement that contains incineration solid waste bottom ash. The compressive strength of the samples was determined at 7, 14, 28 and 90 days. The result was compared to control cement with cement mixture containing incineration waste bottom ash where the result proved that bottom ash cement mixture able achieve its equivalent performance compared to control cement which meeting the requirement of the standards according to EN 196-1. The pozzolanic activity index of bottom ash cement mixture reached 0.92 at 28 days and 0.95 at 90 and this values can be concluded as a pozzolanic material with positive pozzolanic activity. Calcium hydroxide in Portland cement decreasing with the increasing replacement of bottom ash where the reaction occur between Ca(OH)2 and active SiO2.

  2. Microscale Investigation of Arsenic Distribution and Species in Cement Product from Cement Kiln Coprocessing Wastes

    Directory of Open Access Journals (Sweden)

    Yufei Yang

    2013-01-01

    Full Text Available To improve the understanding of the immobilization mechanism and the leaching risk of Arsenic (As in the cement product from coprocessing wastes using cement kiln, distribution and species of As in cement product were determined by microscale investigation methods, including electron probe microanalysis (EPMA and X-ray absorption spectroscopy. In this study, sodium arsenate crystals (Na3AsO412H2O were mixed with cement production raw materials and calcined to produce cement clinker. Then, clinker was mixed water to prepare cement paste. EPMA results showed that As was generally distributed throughout the cement paste. As content in calcium silicate hydrates gel (C-S-H was in low level, but higher than that in other cement mineral phases. This means that most of As is expected to form some compounds that disperse on the surfaces of cement mineral phases. Linear combination fitting (LCF of the X-ray absorption near edge structure spectra revealed that As in the cement paste was predominantly As(V and mainly existed as Mg3(AsO42, Ca3(AsO42, and Na2HAsO4.

  3. Immobilisation of MTR waste in cement (product evaluation)

    International Nuclear Information System (INIS)

    Howard, C.G.; Lee, D.J.

    1988-01-01

    The enriched uranium/aluminium fuel used in Material Testing Reactors is reprocessed at Dounreay Nuclear Power Development Establishment (DNE). The main chemical component of the liquid waste produced by this process is acid deficient aluminium nitrate. The primary objective of this project is to find a suitable process for changing the highly mobile radioactive waste into an inert stable solid. Work carried out on the development of the immobilisation process showed that a conditioning stage (neutralisation) is required to make the acid waste compatible with cement. Small scale experiments showed that adding Ordinary Portland Cement blended with ground granulated Blast Furnace Slag to Simulant MTR Liquor produces an acceptable product. The process has been demonstrated at full scale (200 litres) and the products have been subjected to an extensive programme of destructive and non-destructive testing. (author)

  4. Characterisation of cemented/bituminized LAW and MAW waste products

    International Nuclear Information System (INIS)

    Vejmelka, P.; Johnsen, P.; Kluger, W.; Koester, R.

    1987-01-01

    In the context of work for characterising low and medium activity waste products, investigations were carried out to determine the release of radioactivity from binding waste in given accidents, such as mechanical and thermal loading for the operating phase of a final store. The effects of mechanical loads on MAW cement products and the effects of thermal laods on MAW cement and MAW bitumen products were examined. The release of fine dust reaching the lungs, with a particle size of ≤10 μm from a 200 litre roller seam cement binder with a maximum mechanical load of 3x10 5 Nm covering the accident case is about 1.5 g and therefore corresponds to ≅ 10 -4 % of the total radio-activity inventory for homogeneous products. With thermal loading (60 minute oil fire, 800 0 C) ≅ 10 -3 % of the radioactivity inventory is released via the release of water from the waste binder. The activity release of MAW bitumen products containing NaNO 3 (175 litre drum) with thermal load is considerably higher, as due to the NaNO 3 content of the products, after an induction period of about 20 minutes there is an exothermal reaction between the bitumen and the NaNO 3 , which leads to burning of the bitumen with considerable aerosol formation. The Na losses are about 32% and the Pu losses, derived from the results of laboratory experiments with samples containing Eu and Pu and samples containing Eu on the original size, are only 15% maximum, even with complete burn up. It was shown for all the investigations with samples of the original size that the effects of the load cases considered can be reduced or completely avoided by additional packing (concrete shielding). (orig./RB) [de

  5. Cements in radioactive waste management. Characterization requirements of cement products for acceptance and quality assurance purposes

    International Nuclear Information System (INIS)

    Rahman, A.A.; Glasser, F.P.

    1987-01-01

    Cementitious materials are used as immobilizing matrices for low (LLW) and medium-level wastes (MLW) and are also components of the construction materials in the secondary barriers and the repositories. This report has concerned itself with a critical assessment of the quality assurance aspects of the immobilization and disposal of MLW and LLW cemented wastes. This report has collated the existing knowledge of the use and potential of cementitious materials in radioactive waste immobilization and highlighted the physico-chemical parameters. Subject areas include an assessment of immobilization objectives and cement as a durable material, waste stream and matrix characterization, quality assurance concepts, nature of cement-based systems, chemistry and modelling of cement hydration, role and effect of blending agents, radwaste-cement interaction, assessment of durability, degradative and radiolytic processes in cements and the behaviour of cement-based matrices and their near-field interactions with the environment and the repository conditions

  6. Radioactive waste cementation

    International Nuclear Information System (INIS)

    Soriano B, A.

    1996-01-01

    This research was carried out to develop the most adequate technique to immobilize low and medium-activity radioactive waste. different brands of national cement were used, portland and pozzolanic cement. Prismatic and cylindrical test tubes were prepared with different water/cement (W/C) relationship. Additives such a as clay and bentonite were added in some other cases. Later, the properties of these test tubes were evaluated. Properties such as: mechanical resistance, immersion resistance, lixiviation and porosity resistance. Cement with the highest mechanical resistance values, 62,29 MPa was pozzolanic cement for a W/C relationship of 0,35. It must be mentioned that the other types of cements reached a mechanical resistance over 10 MPa, a value indicated by the international standards for transportation and storage of low and medium-activity radioactive waste at a superficial level. However, in the case of immersion resistance, Sol cement (portland type I) with a W/C relationship of 0,35 reached a compression resistance over 61,92 MPa; as in the previous cases, the other cements reached a mechanical resistance > 10 MPa. Regarding porosity, working with W/C relationships = 0,35 0,40 and 0,45, without additives and with additives, the percentage of porosity found for all cements is lower than 40% percentage indicated by international standards. With regard to the lixiviation test, pozzolanic cement best retained Cesium-137 and Cobalt-60, and increased its advantages when bentonite was added, obtaining a lixiviation rate of 2,02 x E-6 cm/day. Sol cement also improved its properties when bentonite was added and obtained a lixiviation rate of 2,84 x E-6 cm/day for Cesium-137. However, Cobalt-60 is almost completely retained with the 3 types of cement with or without additives, reaching the limits indicated by the international standards for the lixiviation rate of beta-gamma emitter < 5,00E-4 cm/day. Characterizing the final product involves the knowledge of its

  7. Methods and Production of Cementation Materials for Immobilisation into Waste Form. Research of Cementation Processes for Specific Liquid Radioactive Waste Streams of Radiochemical Plants

    International Nuclear Information System (INIS)

    Sukhanov, L.P.

    2013-01-01

    In the near future Russian Federation is planning to use industrial cementation facilities at two radiochemical combines - PA 'Mayak' and Mountain Chemical Combine. Scope of the research within the IAEA CRP contact No. 14176 included the development of cementation processes for specfic liquid radioactive waste streams that are present in these enterprisers. The research on cementation of liquid waste from spent nuclear fuel reprocessing at PA 'Mayak' allowed obtaining experimental data characterizing the technological process and basic characteristics of the produced cement compounds (e.g. mechanical strength, water resistance, frost resistance, flowability, etc.) immobilizing different streams of waste (e.g. hydrated-salt sludges, filter material pulps, mixture of hydrated salt slurries and filter material pulps, tritium liquid waste). Determined optimum technological parameters will allow industrial scale production of cement compound with required quality and higher flowability that is necessary for providing uniform filling of compartments of storage facilities at these sites. The research has been also carried out for the development of cementation technology for immobilization of pulps from storage tanks of Mountain Chemical Combine radiochemical plant. Cementation of such pulps is a difficult technological task because pulps are of complex chemical composition (e.g. hydroxides of manganese, iron, nickel, etc., as well as silicon oxide) and a relatively high activity. The research of cementation process selection for these pulps included studies of the impact of sorbing additive type and content on cement compounds leachability, flowability, impact of cement compound age to its mechanical strength, heat generation of cement compounds and others. The research results obtained allowed testing of cementation facility with a pulse type mixer on the full-scale. Use of such mixer for pulp cementation makes possible to prepare a homogeneous cement compound with the

  8. Utilization of flotation wastes of copper slag as raw material in cement production

    International Nuclear Information System (INIS)

    Alp, I.; Deveci, H.; Suenguen, H.

    2008-01-01

    Copper slag wastes, even if treated via processes such as flotation for metal recovery, still contain heavy metals with hazardous properties posing environmental risks for disposal. This study reports the potential use of flotation waste of a copper slag (FWCS) as iron source in the production of Portland cement clinker. The FWCS appears a suitable raw material as iron source containing >59% Fe 2 O 3 mainly in the form of fayalite (Fe 2 SiO 4 ) and magnetite (Fe 3 O 4 ). The clinker products obtained using the FWCS from the industrial scale trial operations over a 4-month period were characterised for the conformity of its chemical composition and the physico-mechanical performance of the resultant cement products was evaluated. The data collected for the clinker products produced using an iron ore, which is currently used as the cement raw material were also included for comparison. The results have shown that the chemical compositions of all the clinker products including those of FWCS are typical of a Portland cement clinker. The mechanical performance of the standard mortars prepared from the FWCS clinkers were found to be similar to those from the iron ore clinkers with the desired specifications for the industrial cements e.g. CEM I type cements. Furthermore, the leachability tests (TCLP and SPLP) have revealed that the mortar samples obtained from the FWCS clinkers present no environmental problems while the FWCS could act as the potential source of heavy metal contamination. These findings suggest that flotation wastes of copper slag (FWCS) can be readily utilised as cement raw material due to its availability in large quantities at low cost with the further significant benefits for waste management/environmental practices of the FWCS and the reduced production and processing costs for cement raw materials

  9. Utilization of flotation wastes of copper slag as raw material in cement production.

    Science.gov (United States)

    Alp, I; Deveci, H; Süngün, H

    2008-11-30

    Copper slag wastes, even if treated via processes such as flotation for metal recovery, still contain heavy metals with hazardous properties posing environmental risks for disposal. This study reports the potential use of flotation waste of a copper slag (FWCS) as iron source in the production of Portland cement clinker. The FWCS appears a suitable raw material as iron source containing >59% Fe(2)O(3) mainly in the form of fayalite (Fe(2)SiO(4)) and magnetite (Fe(3)O(4)). The clinker products obtained using the FWCS from the industrial scale trial operations over a 4-month period were characterised for the conformity of its chemical composition and the physico-mechanical performance of the resultant cement products was evaluated. The data collected for the clinker products produced using an iron ore, which is currently used as the cement raw material were also included for comparison. The results have shown that the chemical compositions of all the clinker products including those of FWCS are typical of a Portland cement clinker. The mechanical performance of the standard mortars prepared from the FWCS clinkers were found to be similar to those from the iron ore clinkers with the desired specifications for the industrial cements e.g. CEM I type cements. Furthermore, the leachability tests (TCLP and SPLP) have revealed that the mortar samples obtained from the FWCS clinkers present no environmental problems while the FWCS could act as the potential source of heavy metal contamination. These findings suggest that flotation wastes of copper slag (FWCS) can be readily utilised as cement raw material due to its availability in large quantities at low cost with the further significant benefits for waste management/environmental practices of the FWCS and the reduced production and processing costs for cement raw materials.

  10. Immobilisation of MTR waste in cement (product evaluation). Annual report March 1985

    International Nuclear Information System (INIS)

    Howard, C.G.; Smith, D.L.G.; Williams, J.R.A.

    1986-01-01

    This report describes work performed at Winfrith under the UKAEA's research and development programme on radioactive waste management. The work carried out during April 1984 to March 1985 on the evaluation of laboratory and 200 dm 3 scale products of cemented MTR waste was sponsored by the Department of the Environment as part of radioactive waste management research programme. The results will be used in the formulation of Government policy but at this stage they do not necessarily represent Government policy. (author)

  11. Essays of leaching in cemented products containing simulated waste from evaporator concentrated of PWR reactor

    International Nuclear Information System (INIS)

    Haucz, Maria Judite A.; Calabria, Jaqueline A. Almeida; Tello, Cledola Cassia O.; Candido, Francisco Donizete; Seles, Sandro Rogerio Novaes

    2011-01-01

    This paper evaluated the results from leaching resistance essays of cemented products, prepared from three distinct formulations, containing simulated waste of concentrated from the PWR reactor evaporator. The leaching rate is a parameter of qualification of solidified products containing radioactive waste and is determined in accordance with regulation ISO 6961. This procedure evaluates the capacity of transfer organic and inorganic substances presents in the waste through dissolution in the extractor medium. For the case of radioactive waste it is reached the more retention of contaminants in the cemented product, i.e.the lesser value of lixiviation rate. Therefore, this work evaluated among the proposed formulation that one which attend the criterion established in the regulation CNEN-NN-6.09

  12. Elution behavior of heavy metals from cement solidified products of incinerated ash waste - 59102

    International Nuclear Information System (INIS)

    Meguro, Yoshihiro; Kawato, Yoshimi; Nakayama, Takuya; Tomioka, Osamu; Mitsuda, Motoyuki

    2012-01-01

    A method, in which incinerated ash is solidified with a cement material, has been developed to dispose radioactive incinerated ash waste. In order to bury the solidified product, it is required that elution of hazardous heavy metals included in the ash from the solidified products is inhibited. In this study, the elution behavior of the heavy metals from the synthetic solidified products, which included Pb(II), Cd(II), and Cr(VI) and were prepared using ordinary portland cement (OPC), blast furnace slag cement (BFS), or a cement material that showed low alkalinity (LA-Cement), was investigated. Several chemicals and materials were added as additive agents to prevent the elution of the heavy metals. When OPC was used, Cd elution was inhibited, but Pb and Cr were not enough even using the additive agent examined. FeSO 4 and Na 2 S additive agents worked effective to inhibit elution of Cr. When BFS was used, the elution of Pb, Cd and Cr was inhibited for the all products prepared. In the case of LA-Cement, the elution of Pb and Cd was inhibited for the all products, but only the product that was added FeSO 4 showed good result of the elution of Cr. (authors)

  13. Formulation of criteria for pollution control on cement products produced from solid wastes in China.

    Science.gov (United States)

    Yang, Yufei; Huang, Qifei; Yang, Yu; Huang, Zechun; Wang, Qi

    2011-08-01

    The process of producing cement products from solid waste can increase the level of pollutants in the cement products. Therefore, it is very important to establish a pollution control standard for cement products to protect the environment and human health. This paper presents acceptance limits for the availability of heavy metals in cement products which have been produced from solid wastes and explains how the limits have been calculated. The approach and method used to formulate these criteria were based on EN 12920. The typical exposure scenarios used in this paper involve concrete being used for drinking water supply pipelines and concrete pavements and are based on an analysis of typical applications of cement in China, and the potential for contact with water. The parameters of a tank test which was based on NEN 7375 were set in accordance with the environmental conditions of typical scenarios in China. Mechanisms controlling the release of heavy metals in concrete and a model for that release were obtained using the leaching test. Finally, based on acceptance criteria for drinking water and groundwater quality in China, limit values for the availability of heavy metals in concrete were calculated. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Immobilisation of MTR waste in cement (product evaluation). Final report. December 1987

    International Nuclear Information System (INIS)

    Howard, C.G.; Lee, D.J.

    1988-01-01

    The enriched uranium/aluminium fuel used in Material Testing Reactors is reprocessed at Dounreay Nuclear Power Development Establishment (DNE). The main chemical component of the liquid waste produced by this process is acid deficient aluminium nitrate. This is stored in stainless steel tanks at DNE. As a result of work carried out under the UKAEA radioactive waste management programme a decision was taken to immobilise the waste in cement. The programme had two main components, plant design and development of the cementation process. The plant for the cementation of MTR waste is under construction and will be commissioned in 1988/9. The primary objective of this project is to find a suitable process for changing the highly mobile radioactive waste into an inert stable solid. Work carried out on the development of the immobilisation process showed that a conditioning stage (neutralisation) is required to make the acid waste compatible with cement. Small scale experiments showed that adding Ordinary Portland Cement blended with ground granulated Blast Furnace Slag to Simulant MTR Liquor produces an acceptable product. The process has been demonstrated at full scale (200 litres) and the products have been subjected to an extensive programme of destructive and non-destructive testing. Specimens have been tested up to 1200 days after manufacture and show no significant signs of deterioration even when stored underwater or when subjected to freeze thaw cycling. Development work has also shown that the process can successfully immobilise simulant MTR liquor over a wide range of liquor concentrations. The programme therefore successfully produced a formulation that met all the requirements of both the process and product specification. (author)

  15. Characterization of waste products prepared from radioactive contaminated clayey soil cemented according to the GEODUR process

    International Nuclear Information System (INIS)

    Brodersen, K.; Vinther, A.

    1990-11-01

    Radioactive contaminated soil may arise due to accidents of various types or may be detected during decommisioning of nuclear installations. Ordinary surface soil cannot normally be conditioned using conventional cementation processes since the content of humic materials retards or prevents the solidification. An additive available from the Danish firm Geodur A/S makes it possible to circumvent this difficulty and to produce a monolithic, nondusting waste type using rather small amounts of cement. The report describes work on characterization of such a cemented waste product prepared on basis of clayey top soil from the Risoe area. The claimed advantages of the process was verified, and data for the compression strength (low), hydraulic conductivity (satisfactory) and other pore structure-related properties are given for the obtained products. Unfortunately the behaviour of cesium and strontium, representing two of the most relevant radionuclides, was not too promising. The retention of cesium is satisfactory, but less good than for the untreated soil. Greatly improved cesium retention after drying of the materials was noticed. Good retention of strontium is only obtained after reaction of the material with carbon dioxide from the atmosphere. The behaviour of the two isotopes in other types of cemented waste is somewhat similar, but the decrease in retention compared with untreated soil makes the process less interesting as a possibility for remedial actions after accidents, etc. Some further studies of the cemented soil waste are beeing made within the frame of the Nordic Nuclear Safety Studies. Elements forming low solublity components in the high pH environment in the cemented soil will probably be retained quite efficiently. This was demonstrated in case of Zn. (author) 11 tabs., 22 ills., 8 refs

  16. Effect of AlF3 Production Waste on the Properties of Hardened Cement Paste

    Directory of Open Access Journals (Sweden)

    Danutė VAIČIUKYNIENĖ

    2012-06-01

    Full Text Available The possibility to use by-product SiO2·nH2O (often called AlF3 production waste in cement casting has been attracting the interest of researchers for many years, although high content of fluorine makes the use of amorphous SiO2 problematic. Finding the way of utilizing waste products is a very important research topic at the moment. In this study AlF3 production waste was investigated as the basic ingredient of a new pozzolanic material. The goal of this study is to investigate the possibilities of using AlF3 production waste, washed in ammonia solution, in cement stone specimens. Chemically treated silica gel additive was proved to reduce the amount of Ca(OH2 and CaCO3 in hardened cement paste samples. Experimental research has revealed that the density in hydrated samples reduces from 2220 kg/m3 to 2030 kg/m3 with the increase of silica gel content from 0 % to 35 %. The compressive strength of samples containing 10 % of silica gel additive increased by 8.04 % compared to the samples without the additive. SiO2 additive used at 10 % and 20 % increased the maximum hydration temperature. In this case, the additive modifies the hydration kinetics.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1925

  17. Exergetic life cycle assessment of cement production process with waste heat power generation

    International Nuclear Information System (INIS)

    Sui, Xiuwen; Zhang, Yun; Shao, Shuai; Zhang, Shushen

    2014-01-01

    Highlights: • Exergetic life cycle assessment was performed for the cement production process. • Each system’s efficiency before and after waste heat power generation was analyzed. • The waste heat power generation improved the efficiency of each production system. • It provided technical support for the implementation of energy-saving schemes. - Abstract: The cement industry is an industry that consumes a considerable quantity of resources and energy and has a very large influence on the efficient use of global resources and energy. In this study, exergetic life cycle assessment is performed for the cement production process, and the energy efficiency and exergy efficiency of each system before and after waste heat power generation is investigated. The study indicates that, before carrying out a waste heat power generation project, the objective energy efficiencies of the raw material preparation system, pulverized coal preparation system and rotary kiln system are 39.4%, 10.8% and 50.2%, respectively, and the objective exergy efficiencies are 4.5%, 1.4% and 33.7%, respectively; after carrying out a waste heat power generation project, the objective energy efficiencies are 45.8%, 15.5% and 55.1%, respectively, and the objective exergy efficiencies are 7.8%, 2.8% and 38.1%, respectively. The waste heat power generation project can recover 3.7% of the total input exergy of a rotary kiln system and improve the objective exergy efficiencies of the above three systems. The study can identify degree of resource and energy utilization and the energy-saving effect of a waste heat power generation project on each system, and provide technical support for managers in the implementation of energy-saving schemes

  18. The effectivity of bentonites in cesium retention of cemented waste products

    International Nuclear Information System (INIS)

    Tello, Cledola Cassia Oliveira de

    2001-01-01

    The nuclear energy has been used for the human development in different areas, as in the medicine, in the agriculture, in the industry and in the environmental protection, besides the electricity generation. As in other activities, in the use of nuclear energy, residues are also generated. They are considered radioactive wastes when the contaminant content can bring a potential negative impact in the human health and in the environment. In this case they should be properly managed and should not be released without treatment. In general the waste processing consists in a volume reduction followed by solidification and/or conditioning. A number of materials can be considered as immobilisation matrices for the wastes, with the objective of maintain the radioactive material physical and chemically stable. The cement is extensively used because it is easy to obtain, there is large. experience in its use and the processing is done at room temperature. Many materials have been studied to improve the fixation characteristics of the radionuclides in the cemented product. The aim of this study was to search, among Brazilian natural materials, those that could be effective in the contaminant retention without jeopardising the process and other characteristics of the waste product. Four types of bentonite were selected to the process and product evaluation tests. Many mixtures were prepared with simulated waste, cement and bentonite in different proportions. The viscosity, set time, compressive strength and leaching were evaluated. In addition it was verified if the products were monolithic and without free water. Inactive caesium was used as tracer. The leaching resistance is the most important parameter in the product evaluation, because it indicates the retention capacity of the matrix for radionuclides when the product is in contact with the water. In 1985 leaching tests were begun and they have been continued till now and from their results it was proved that the

  19. Cement plate slab production with the incorporation of glass wool waste ground

    Directory of Open Access Journals (Sweden)

    Nathany Angélica dos Santos

    Full Text Available Abstract One of the characteristics of Civil Construction is its ability to absorb a wide range of wastes to produce new products. Therefore, the objective of this study was to evaluate the behavior of cement plates produced with the addition of ground glass wool waste and in natura, in shredded form. The tensile strength tests in bending and permeability were performed, according to ABNT NBR 15498: 2007 as well as environmental ones according to ABNT NBR 10004: 2004. The plates produced in this study were characterized as being impermeable, with a satisfactory tensile strength in bending and being classified as plates for indoor and outdoor use, and as products that do not offer immediate risk to health and to the environment; however, it should be discarded in landfill.

  20. Cementation of liquid radioactive waste

    International Nuclear Information System (INIS)

    Efremenkov, V.

    2004-01-01

    The cementation methods for immobilisation of radioactive wastes are discussed in terms of methodology, chemistry and properties of the different types of cements as well as the worldwide experience in this field. Two facilities for cementation - DEWA and MOWA - are described in details

  1. Development of an immobilisation technique by cementation for non-radioactive simulated liquid waste, from Mo-99 production process

    International Nuclear Information System (INIS)

    Arva, E A; Marabini, S G; Varani, J L

    2012-01-01

    The Argentine Atomic Energy Commission (CNEA) is the responsible for developing a management nuclear waste disposal programme. This programme contemplates the strictly environmental safe and efficient management of the radioactive waste from different sources. Since 1985, CNEA has been producing commercially Mo-99 for medical use. In this process two types of liquid waste are produced. One of them has high alkaline (NaOH 3,5M) and aluminate contents. Since Mo-99 production started, such liquid waste was stored in specially designed containers during production, and after a decay period in smaller containers in interim storage conditions. As this waste is still a liquid, development of an immobilisation technique is required. Immobilisation of radioactive liquid waste by cementation is a frequently used technique, and will be studied in the present work using Mo-99 non-radioactive simulated liquid waste. In this second stage, a full scale (200 liters drum) cementation test using simulated non radioactive waste was carried out. Such test included: using the BEBA 201 mixing machine - the same that will be used with real waste in the future for 'tuning up' the process, construction of a specially designed temperature sensor for measuring the maximum temperature value (five different positions, four inside the drum and one outside) and the time elapsed after all components mixing. Finally, standard specimens (IRAM 1622) were made for mechanical resistance tests after cement setting at 28 days. The results show values of temperature not above 40 o C with the maximum at 12 hours before component mixing and compression strength of 14 MPa. Such values are compatible for a waste immobilisation process by cementation (author)

  2. Studies on the Potential of Waste Soda Lime Silica Glass in Glass Ionomer Cement Production

    Directory of Open Access Journals (Sweden)

    V. W. Francis Thoo

    2013-01-01

    Full Text Available Glass ionomer cements (GIC are produced through acid base reaction between calcium-fluoroaluminosilicate glass powder and polyacrylic acid (PAA. Soda lime silica glasses (SLS, mainly composed of silica (SiO2, have been utilized in this study as the source of SiO2 for synthesis of Ca-fluoroaluminosilicate glass. Therefore, the main objective of this study was to investigate the potential of SLS waste glass in producing GIC. Two glasses, GWX 1 (analytical grade SiO2 and GWX 2 (replacing SiO2 with waste SLS, were synthesized and then characterized using X-ray diffraction (XRD and energy dispersive X-ray (EDX. Synthesized glasses were then used to produce GIC, in which the properties were characterized using Fourier transform infrared spectroscopy (FT-IR and compressive test (from 1 to 28 days. XRD results showed that amorphous glass was produced by using SLS waste glass (GWX 2, which is similar to glass produced using analytical grade SiO2 (GWX 1. Results from FT-IR showed that the setting reaction of GWX 2 cements is slower compared to cement GWX 1. Compressive strengths for GWX 1 cements reached up to 76 MPa at 28 days, whereas GWX 2 cements showed a slightly higher value, which is 80 MPa.

  3. Cement As a Waste Form for Nuclear Fission Products: The Case of (90)Sr and Its Daughters.

    Science.gov (United States)

    Dezerald, Lucile; Kohanoff, Jorge J; Correa, Alfredo A; Caro, Alfredo; Pellenq, Roland J-M; Ulm, Franz J; Saúl, Andrés

    2015-11-17

    One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of (90)Sr insertion and decay in C-S-H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that (90)Sr is stable when it substitutes the Ca(2+) ions in C-S-H, and so is its daughter nucleus (90)Y after β-decay. Interestingly, (90)Zr, daughter of (90)Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for (90)Sr storage.

  4. Cementation of wastes with boric acid

    International Nuclear Information System (INIS)

    Tello, Cledola C.O.; Haucz, Maria Judite A.; Alves, Lilian J.L.; Oliveira, Arno H.

    2000-01-01

    In nuclear power plants (PWR) are generated wastes, such as concentrate, which comes from the evaporation of liquid radioactive wastes, and spent resins. Both have boron in their composition. The cementation process is one of the options to solidify these wastes, but the boron has a negative effect on the setting of the cement mixture. In this paper are presented the experiments that are being carried out in order to overcome this problem and also to improve the efficiency of the process. Simulated wastes were cemented using additives (clays, admixtures etc.). In the process and product is being evaluated the effect of the amount, type and addition order of the materials. The mixtures were selected in accordance with their workability and incorporated waste. The solidified products are monolithic without free water with a good mechanical resistance. (author)

  5. Immobilisation of shredded waste in a cement monolith

    International Nuclear Information System (INIS)

    James, J.M.; Smith, D.L.

    1987-11-01

    During 1983/84 work was continued on the development of the process for the encapsulation of shredded waste in cement. Using simulant shredded waste the conditions for operating the process on the 500 litres scale have been established. Evaluation of the cemented product showed that it was satisfactorily infilled with cement grout with no significant voidage. (author)

  6. Preparation of magnesium phosphate cement by recycling the product of thermal transformation of asbestos containing wastes

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Gualtieri, A.F.

    2014-01-01

    Roč. 58, April (2014), s. 56-66 ISSN 0008-8846 R&D Projects: GA MŠk(CZ) LO1219 Institutional support: RVO:68378297 Keywords : cement-asbestos * chemically bonded ceramics * waste management * X-ray diffraction * amorphous material Subject RIV: JN - Civil Engineering Impact factor: 2.864, year: 2014 http://www.sciencedirect.com/science/article/pii/S000888461400012X

  7. Cement-Based Materials for Nuclear Waste Storage

    CERN Document Server

    Cau-di-Coumes, Céline; Frizon, Fabien; Lorente, Sylvie

    2013-01-01

    As the re-emergence of nuclear power as an acceptable energy source on an international basis continues, the need for safe and reliable ways to dispose of radioactive waste becomes ever more critical. The ultimate goal for designing a predisposal waste-management system depends on producing waste containers suitable for storage, transportation and permanent disposal. Cement-Based Materials for Nuclear-Waste Storage provides a roadmap for the use of cementation as an applied technique for the treatment of low- and intermediate-level radioactive wastes.Coverage includes, but is not limited to, a comparison of cementation with other solidification techniques, advantages of calcium-silicate cements over other materials and a discussion of the long-term suitability and safety of waste packages as well as cement barriers. This book also: Discusses the formulation and production of cement waste forms for storing radioactive material Assesses the potential of emerging binders to improve the conditioning of problemati...

  8. Complex research and qualification methods of cement products for the processing, accumulation and storage of radioactive waste

    International Nuclear Information System (INIS)

    Kovalinska, T.; Ostapenko, I.; Sakhno, V.

    2015-01-01

    INR (Ukrainian Institute for Nuclear Research) has developed an installation to assess the degradation of cements and concretes over accelerated time and in hard operating conditions involving mechanical and chemical effects, radiation, high temperatures, electric fields...This testing installation is called a reactionary chamber. The experimental data obtained during these tests characterize the product functionality in the stationary, transitional and emergency modes. These data allow the solving of the equation system representing the state of a product at a current moment of time and to determine its reactions to various external influences. An example is given through the testing of concrete containers that are intended to store radioactive waste

  9. Leaching tests of cemented organic radioactive waste

    International Nuclear Information System (INIS)

    Calabria, Jaqueline A. Almeida; Haucz, Maria Judite A.; Tello, Cledola Cassia O.

    2011-01-01

    The use of radioisotopes in research, medical and industrial activities generates organic liquid radioactive wastes. At Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) are produced organic liquid wastes from different sources, one of these are the solvent extraction activities, whose the waste volume is the largest one. Therefore a research was carried out to treat them. Several techniques to treat organic liquid radioactive wastes have been evaluated, among them incineration, oxidation processes, alkaline hydrolysis, distillation, absorption and cementation. Laboratory experiments were accomplished to establish the most adequate process in order to obtain qualified products for storage and disposal. Absorption followed by cementation was the procedure used in this study, i.e. absorbent substances were added to the organic liquid wastes before mixing with the cement. Initially were defined the absorbers, and evaluated the formulation in relation to the compressive strength of its products. Bentonite from different suppliers (B and G) and vermiculite in two granulometries (M - medium and F - small) were tested. In order to assess the product quality the specimens were submitted to the leaching test according the Standard ISO 6961 and its results were evaluated. Then they were compared with the values established by Standard CNEN NN 6.09 A cceptance criteria for waste products to be disposed , to verify if they meet the requirements for safely storage and disposal. Through this study the best formulations to treat the organic wastes were established. (author)

  10. Basalt waste added to Portland cement

    Directory of Open Access Journals (Sweden)

    Thiago Melanda Mendes

    2016-08-01

    Full Text Available Portland cement is widely used as a building material and more than 4.3 billion tons were produced in 2014, with increasing environmental impacts by this industry, mainly through CO2 emissions and consumption of non-removable raw materials. Several by-products have been used as raw materials or fuels to reduce environmental impacts. Basaltic waste collected by filters was employed as a mineral mixture to Portland cement and two fractions were tested. The compression strength of mortars was measured after 7 days and Scanning Electron Microscopy (SEM and Electron Diffraction Scattering (EDS were carried out on Portland cement paste with the basaltic residue. Gains in compression strength were observed for mixtures containing 2.5 wt.% of basaltic residue. Hydration products observed on surface of basaltic particles show the nucleation effect of mineral mixtures. Clinker substitution by mineral mixtures reduces CO2 emission per ton of Portland cement.

  11. Cementation unit for radioactive wastes

    International Nuclear Information System (INIS)

    Dellamano, Jose Claudio; Vicente, Roberto; Lima, Jose Rodrigues de

    2001-01-01

    This communication describes the waste cementation process and facility developed at Instituto de Pesquisas Energeticas e Nucleares - IPEN. The process is based on 200 litres batch operation, in drum mixing, with continuous cement feeding. The equipment is a single recoverable helicoidal mixer and a turning table that allows the drum to rotate during the mixing operation, simulating a planetary mixer. The facility was designed to treat contact handled liquids and wet solid wastes, but can be adapted for shielded equipment and remote operation. (author)

  12. Design and application of environmentally effective concrete with usage of chrysotile-cement waste

    OpenAIRE

    Egorova Lada; Semenov Vyacheslav; Pligina Anna; Askhadullin Aizat

    2016-01-01

    Construction is resource-demanding industry, characterized by a large volume of waste. Particularly chrysotile cement waste obtained both in production and in dismantling over age chrysotile-cement products: corrugated asbestos boards and flat sheets, chrysotile-cement tubes. We propose to use dry chrysotile-cement waste as recycled aggregate for concrete. Based on developed compositions and identified properties of heavy concrete with chrysotile-cement waste introduce this technology to the ...

  13. The fixation of radioactive wastes in cement

    International Nuclear Information System (INIS)

    Kulichenko, V.V.; Dukhovich, F.S.; Volkova, O.I.; Boyarinova, M.V.

    1976-01-01

    The authors study the leaching behaviour of the main long-lived fission products 90 Sr and 137 Cs. It is found that 90 Sr and 137 Cs have high elution values, namely (2-12) x 10 -2 resp. (2-6) x 10 -2 g/cm 2 /24h, independently of the type of waste. On the basis of these results, maximum concentrations for the solutions in the cement/solution mixtures are proposed. Further studies relate to the formation of radiolysis gas in the waste fixed to cement. Experiments are described to make use of the empty space in the containers, filled with solid waste by filling them with mixtures of cement and liquid radioactive waste of 10 -4 to 1- 6 Ci. The ratio solution/cement should amount to 0.5. The containers are then buried underground. This method of combined waste storage helped to reduce the cost for the storage of liquid waste by about 40-50%. (RB) [de

  14. The Optimization of Immobilization for the Low-Activity Waste of theEvaporation Product with Cement

    International Nuclear Information System (INIS)

    Supardi

    2000-01-01

    The experimental investigation of immobilization the low active wasteconcentration containing 2.44x10 -3 μCi/cc a great deal of NaNO 3 withcement was done. The immobilization process was carried out by mixing cement,water, concentrate, and Ca-bentonite with a given ratio within a glassbeaker. The mixture was then stirred with an electrical hand mixer untilhomogeneous. The studied immobilization condition were the influences of theweight ratio water to cement, the weight ratio of concentrate to cement withwhich the concentrate pH was varied, and the influence of the addition ofCa-bentonite (% in weight) with the optimum pH of concentrate. The sample inthe container with the size of 2.54 cm in diameter and 3.0 cm in height wasmade of polyethylene and was covered by a tight lid and was cured for 28days. After the sample was cured for 28 days and then it was taken out of thecontainer. This sample quality was ready for being tested. The quality ofcementation product tested compressive strength, density, chemical stability,irradiation stability and thermal stability. The optimum results ofinvestigation were the weight ratio of water to cement = 0.30, thecompressive strength of 30.37 N/mm 2 . For the immobilization of the waste andcement with the optimum pH being used, yielded in the compressive strength of28.07 N/mm 2 . Further more from the condition of waste and cement at theoptimum pH which was added by the optimum Ca-bentonite gained the compressivestrength of 33.64 N/mm 2 before irradiation, where as after irradiation thecompressive strength was 32.41 N/mm 2 . The optimum thermal test resultachieved was 250 o C with the compressive strength of 44.10 N/mm 2 . For theleaching test results after being cured for 91 days in the distilled watermedia was 0.47x10 -4 gcm -2 day -1 , while in the sea water was 0.66x10 -4 gcm -2 day -1 . Water medium activity until 91 days = 3.1x10 -7 μCi/cc,MPC from ICRP = 8.1x10 -7 μCi/cc. The experimental investigation ofcemented waste

  15. Processing method for cleaning water waste from cement kneader

    International Nuclear Information System (INIS)

    Soda, Kenzo; Fujita, Hisao; Nakajima, Tadashi.

    1990-01-01

    The present invention concerns a method of processing cleaning water wastes from a cement kneader in a case of processing liquid wastes containing radioactive wastes or deleterious materials such as heavy metals by means of cement solidification. Cleaning waste wastes from the kneader are sent to a cleaning water waste tank, in which gentle stirring is applied near the bottom and sludges are retained so as not to be coagulated. Sludges retained at the bottom of the cleaning water waste tank are sent after elapse of a predetermined time and then kneaded with cements. Thus, since the sludges in the cleaning water are solidified with cement, inhomogenous solidification products consisting only of cleaning sludges with low strength are not formed. The resultant solidification product is homogenous and the compression strength thereof reaches such a level as capable of satisfying marine disposal standards required for the solidification products of radioactive wastes. (I.N.)

  16. Cements in Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    Glasser, F.P.

    2013-01-01

    The use of cement and concrete to immobilise radioactive waste is complicated by the wide- ranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These constructions may experience a long pre-closure performance lifetime during which they are required to protect against collapse and ingress of water: strength and impermeability are key desirable characteristics. On the other hand, cement and concrete may be used to form backfills, ranging in permeability. Permeable formulations allow gas readily to escape, while impermeable barriers retard radionuclide transport and reduce access of ground water to the waste. A key feature of cements is that, while fresh, they pass through a fluid phase and can be formed into any shape desired or used to infiltrate other materials thereby enclosing them into a sealed matrix. Thereafter, setting and hardening is automatic and irreversible. Where concrete is used to form structural elements, it is also natural to use cement in other applications as it minimises potential for materials incompatibility. Thus cement- mainly Portland cement- has been widely used as an encapsulant for storage, transport and as a radiation shield for active wastes. Also, to form and stabilise structures such as vaults and silos. Relative to other potential matrices, cement also has a chemical immobilisation potential, reacting with and binding with many radionuclides. The chemical potential of cements is essentially sacrificial, thus limiting their performance lifetime. However performance may also be required in the civil engineering sense, where strength is important, so many factors, including a geochemical description of service conditions, may require to be assessed in order to predict performance lifetime. The

  17. Cements in Radioactive Waste Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Glasser, F. P. [University of Aberdeen, Scotland (United Kingdom)

    2013-09-15

    The use of cement and concrete to immobilise radioactive waste is complicated by the wide- ranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These constructions may experience a long pre-closure performance lifetime during which they are required to protect against collapse and ingress of water: strength and impermeability are key desirable characteristics. On the other hand, cement and concrete may be used to form backfills, ranging in permeability. Permeable formulations allow gas readily to escape, while impermeable barriers retard radionuclide transport and reduce access of ground water to the waste. A key feature of cements is that, while fresh, they pass through a fluid phase and can be formed into any shape desired or used to infiltrate other materials thereby enclosing them into a sealed matrix. Thereafter, setting and hardening is automatic and irreversible. Where concrete is used to form structural elements, it is also natural to use cement in other applications as it minimises potential for materials incompatibility. Thus cement- mainly Portland cement- has been widely used as an encapsulant for storage, transport and as a radiation shield for active wastes. Also, to form and stabilise structures such as vaults and silos. Relative to other potential matrices, cement also has a chemical immobilisation potential, reacting with and binding with many radionuclides. The chemical potential of cements is essentially sacrificial, thus limiting their performance lifetime. However performance may also be required in the civil engineering sense, where strength is important, so many factors, including a geochemical description of service conditions, may require to be assessed in order to predict performance lifetime. The

  18. Comparative analysis of compressive strength tests at age of 28 and 90 days and density of products using chemical additives in cementing radioactive waste

    International Nuclear Information System (INIS)

    Vieira, Vanessa Mota; Tello, Cledola Cassia Oliveira de

    2013-01-01

    In this research it has been studied the effects of chemical additives (admixtures) in the cementation process of radioactive wastes, which are used to improve the properties of waste cementation process, both of the paste and of the solidified product. However there are a large variety of these materials that are frequently changed or taken out of the market, then it is essential to know the commercially available materials and their effects. The tests were carried out with a solution simulating the evaporator concentrate waste coming from PWR nuclear reactors. It was cemented using two formulations, A and B, incorporating higher or lower amount of waste, respectively. It was added chemical admixtures from two manufacturers (S and H), which were: accelerators, set retarders and superplasticizers. The experiments were organized by a factorial design 2 3 . The measured parameters were the viscosity, the setting time, the paste and product density and the compressive strength. In this study we performed comparative analyzes of the results of compressive strength at age of 28 and 90 days and between the densities of the samples at the same ages.The compressive strength test at age of 28 days is considered a parameter essential issues related to security handling, transport and storage of cemented waste product. The results showed that the addition of accelerators improved the compressive strength of the cemented product, but presented lower values density products. (author)

  19. Comparison of modified sulfur cement and hydraulic cement for encapsulation of radioactive and mixed wastes

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Colombo, P.

    1990-01-01

    The majority of solidification/stabilization systems for low-level radioactive waste (LLW) and mixed waste, both in the commercial sector and at Department of Energy (DOE) facilities, utilize hydraulic cement (such as portland cement) to encapsulate waste materials and yield a monolithic solid waste form for disposal. Because hydraulic cement requires a chemical hydration reaction for setting and hardening, it is subject to potential interactions between elements in the waste and binder that can retard or prevent solidification. A new and innovative process utilizing modified sulfur cement developed by the US Bureau of Mines has been applied at Brookhaven National Laboratory (BNL) for the encapsulation of many of these problem wastes. Modified sulfur cement is a thermoplastic material, and as such, it can be heated above its melting point, combined with dry waste products to form a homogeneous mixture, and cooled to form a monolithic solid product. Under sponsorship of the DOE, research and development efforts at BNL have successfully applied the modified sulfur cement process for treatment of a range of LLWs including sodium sulfate salts, boric acid salts, and incinerator bottom ash and for mixed waste contaminated incinerator fly ash. Process development studies were conducted to determine optimal waste loadings for each waste type. Property evaluation studies were conducted to test waste form behavior under disposal conditions by applying relevant performance testing criteria established by the Nuclear Regulatory Commission (for LLW) and the Environmental Protection Agency (for hazardous wastes). Based on both processing and performance considerations, significantly greater waste loadings were achieved using modified sulfur cement when compared with hydraulic cement. Technology demonstration of the modified sulfur cement encapsulation system using production-scale equipment is scheduled for FY 1991

  20. The suitability of a supersulfated cement for nuclear waste immobilisation

    Energy Technology Data Exchange (ETDEWEB)

    Collier, N.C., E-mail: nick.collier@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Milestone, N.B. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Callaghan Innovation, 69 Gracefield Road, PO Box 31310, Lower Hutt 5040 (New Zealand); Gordon, L.E. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Geopolymer and Minerals Processing Group, Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Victoria 3010 (Australia); Ko, S.-C. [Holcim Technology Ltd, Hagenholzstrasse 85, CH-8050 Zurich (Switzerland)

    2014-09-15

    Highlights: • We investigate a supersulfated cement for use as a nuclear waste encapsulant. • High powder fineness requires a high water content to satisfy flow requirements. • Heat generation during hydration is similar to a control cement paste. • Typical hydration products are formed resulting in a high potential for waste ion immobilisation. • Paste pH and aluminium corrosion is less than in a control cement paste. - Abstract: Composite cements based on ordinary Portland cement are used in the UK as immobilisation matrices for low and intermediate level nuclear wastes. However, the high pore solution pH causes corrosion of some metallic wastes and undesirable expansive reactions, which has led to alternative cementing systems being examined. We have investigated the physical, chemical and microstructural properties of a supersulfated cement in order to determine its applicability for use in nuclear waste encapsulation. The hardened supersulfated cement paste appeared to have properties desirable for use in producing encapsulation matrices, but the high powder specific surface resulted in a matrix with high porosity. Ettringite and calcium silicate hydrate were the main phases formed in the hardened cement paste and anhydrite was present in excess. The maximum rate of heat output during hydration of the supersulfated cement paste was slightly higher than that of a 9:1 blastfurnace slag:ordinary Portland cement paste commonly used by the UK nuclear waste processing industry, although the total heat output of the supersulfated cement paste was lower. The pH was also significantly lower in the supersulfated cement paste. Aluminium hydroxide was formed on the surface of aluminium metal encapsulated in the cement paste and ettringite was detected between the aluminium hydroxide and the hardened cement paste.

  1. The suitability of a supersulfated cement for nuclear waste immobilisation

    International Nuclear Information System (INIS)

    Collier, N.C.; Milestone, N.B.; Gordon, L.E.; Ko, S.-C.

    2014-01-01

    Highlights: • We investigate a supersulfated cement for use as a nuclear waste encapsulant. • High powder fineness requires a high water content to satisfy flow requirements. • Heat generation during hydration is similar to a control cement paste. • Typical hydration products are formed resulting in a high potential for waste ion immobilisation. • Paste pH and aluminium corrosion is less than in a control cement paste. - Abstract: Composite cements based on ordinary Portland cement are used in the UK as immobilisation matrices for low and intermediate level nuclear wastes. However, the high pore solution pH causes corrosion of some metallic wastes and undesirable expansive reactions, which has led to alternative cementing systems being examined. We have investigated the physical, chemical and microstructural properties of a supersulfated cement in order to determine its applicability for use in nuclear waste encapsulation. The hardened supersulfated cement paste appeared to have properties desirable for use in producing encapsulation matrices, but the high powder specific surface resulted in a matrix with high porosity. Ettringite and calcium silicate hydrate were the main phases formed in the hardened cement paste and anhydrite was present in excess. The maximum rate of heat output during hydration of the supersulfated cement paste was slightly higher than that of a 9:1 blastfurnace slag:ordinary Portland cement paste commonly used by the UK nuclear waste processing industry, although the total heat output of the supersulfated cement paste was lower. The pH was also significantly lower in the supersulfated cement paste. Aluminium hydroxide was formed on the surface of aluminium metal encapsulated in the cement paste and ettringite was detected between the aluminium hydroxide and the hardened cement paste

  2. Actinides in intermediate-level liquid waste: removal by oxalic acid precipitation followed by cement incorporation and characterization of the final product

    International Nuclear Information System (INIS)

    Bokelund, H.; Lebrun, M.; Ougier, M.; de Caritat de Peruzzis, G.

    1991-01-01

    The purpose of this study was to investigate the conditions for the provision of an alpha free waste form (non-TRU waste with 5000) and adequate (70) DF-values were found for americium and for plutonium, respectively, with calcium as the preferred carrier. No difference between simulated and genuine ILLW was found. The final cement product was investigated by measurements of its mechanical and chemical properties. The compressive strength was evaluated as functions of the ageing time and the salt content of the waste incorporated. Furthermore, the change of porosity of the product and its resistance to water leaching were tested. The study was carried out on both simulated and genuine ILLW samples. The use of microsilica as an additive to the cement gave significant improvements in the performance of the matrix: the compressive strength was increased and, more pronounced, the leachability was decreased by up to 50%. No detrimental effects of oxalates on the cement matrix were found

  3. Effect of olive waste (Husk on behavior of cement paste

    Directory of Open Access Journals (Sweden)

    Sharaf Alkheder

    2016-12-01

    Full Text Available Jordan is a famous country in terms of olive trees agriculture that resulted in a mass production of olive oil products. The huge amounts of olive waste (husk that resulted from olives processing to produce olive oil represent an environmental challenge in the country. The idea in this paper comes to use olive waste as a partial replacement for Portland cement in cement paste to conserve the environment, reduce cement consumption and increase cost efficiency. The wastes were burned properly in an oven and maintained for 6 h until it was fully transformed into ashes. Then, the oven was turned off and ashes were allowed to cool. After cooling, the material passed sieve #200 were used. The sieved ashes were used in the cement mix as a partial cement replacement for making the mortar and cement paste. Normal consistency and setting time were determined as well as soundness, compressive strength. Results indicated that normal consistency of the cement pastes containing different percentage of olive waste is somehow lower than that of the ordinary cement paste and slightly decreases with increasing the percentage. The results also indicated that the compressive strength of hardened blended cement paste containing different percentages of olive waste slightly decrease with olive waste content at 3, 7, and 28 days.

  4. VUJE experience with cementation of liquid and wet radioactive waste

    International Nuclear Information System (INIS)

    Kravarik, Kamil; Holicka, Zuzana; Pekar, Anton; Zatkulak, Milan

    2011-01-01

    Liquid and wet LLW generated during operation as well as decommissioning of NPPs is treated with different methods and fixed in a suitable fixation matrix so that a final product meets required criteria for its disposal in a final repository. Cementation is an important process used for fixation of liquid and wet radioactive waste such as concentrate, spent resins and sludge. Active cement grout is also used for fixation of low level solid radioactive waste loaded in final packing containers. VUJE Inc. has been engaged in research of cementation for long. The laboratory for analyzing radioactive waste properties, prescription of cementation formulation and estimation of final cement product properties has been established. Experimental, semi-production cementation plant has been built to optimize operation parameters of cementation. VUJE experience with cementation of liquid and wet LLW is described in the presented paper. VUJE has assisted in commissioning of Jaslovske Bohunice Treatment Centre. Cement formulations for treatment of concentrate, spent resins and sludge have been developed. Research studies on the stability of a final concrete packaging container for disposal in repository have been performed. Gained experience has been further utilized for design and manufacture of several cementation plants for treatment of various liquid and wet LLW. Their main technological and technical parameters as well as characterization of treated waste are described in the paper. Applications include the Mochovce Final Treatment Centre, Movable Cementation Facility utilizing in-drum mixing for treatment of sludge, Cementation Facility for treatment of tritiated water in Latvia and Cementation Facility for fixation of liquid and solid institutional radioactive waste in Bulgaria, which utilizes lost stirrer mixer. (author)

  5. PURIFIED WASTE FCC CATALYST AS A CEMENT REPLACEMENT MATERIAL

    Directory of Open Access Journals (Sweden)

    Danute Vaiciukyniene

    2015-06-01

    Full Text Available Zeolites are commonly used in the fluid catalytic cracking process. Zeolite polluted with oil products and became waste after some time used. The quantity of this waste inevitably rises by expanding rapidly oil industry. The composition of these catalysts depends on the manufacturer and on the process that is going to be used. The main factors retarding hydration process of cement systems and modifying them strength are organic compounds impurities in the waste FCC catalyst. The present paper shows the results of using purified waste FCC catalyst (pFCC from Lithuania oil refinery, as Portland cement replacement material. For this purpose, the purification of waste FCC catalyst (FCC samples was treated with hydrogen peroxide. Hydrogen peroxide (H2O2 is one of the most powerful oxidizers known. By acting of waste with H2O2 it can eliminate the aforementioned waste deficiency, and the obtained product becomes one of the most promising ingredients, in new advanced building materials. Hardened cement paste samples with FCC or pFCC were formed. It was observed that the pFCC blended cements developed higher strength, after 28 days, compared to the samples with FCC or reference samples. Typical content of Portland cement substituting does not exceed 30 % of mass of Portland cement in samples. Reducing the consumption of Portland cement with utilizing waste materials is preferred for reasons of environmental protection.

  6. Conditioning of radioactive waste solutions by cementation

    International Nuclear Information System (INIS)

    Vejmelka, P.; Rudolph, G.; Kluger, W.; Koester, R.

    1992-02-01

    For the cementation of the low and intermediate level evaporator concentrates resulting from the reprocessing of spent fuel numerous experiments were performed to optimize the waste form composition and to characterize the final waste form. Concerning the cementation process, properties of the waste/cement suspension were investigated. These investigations include the dependence of viscosity, bleeding, setting time and hydration heat from the waste cement slurry composition. For the characterization of the waste forms, the mechanical, thermal and chemical stability were determined. For special cases detailed investigations were performed to determine the activity release from waste packages under defined mechanical and thermal stresses. The investigations of the interaction of the waste forms with aqueous solutions include the determination of the Cs/Sr release, the corrosion resistance and the release of actinides. The Cs/Sr release was determined in dependence of the cement type, additives, setting time and sample size. (orig./DG) [de

  7. Safety disposal studies of radioactive and hazardous wastes using cement

    International Nuclear Information System (INIS)

    Aly, M.M.E.

    2000-01-01

    radioactive waste is generated from the production of nuclear energy and from the use of radioactive materials applications, agriculture and medicine. the important of safe management of radioactive waste for the protection of human health and the environment has long been recognized. conditioning of radioactive waste is the transform of radioactive waste into a suitable form for storage and disposal. common immobilization methods include solidification of low radioactive waste in cement or bitumen.in order to improve cement properties to decrease the release of liquid radioactive waste into the environment and its dispersion to a level where the risks to individuals, population and the environment

  8. The incorporation of low and medium level radioactive wastes (solids and liquids) in cement

    International Nuclear Information System (INIS)

    Palmer, J.D.; Smith, D.L.G.

    1986-01-01

    The use of cement has been investigated for the immobilization of liquid and solid low and medium level radioactive waste. 220 litre mixing trials have demonstrated that the high temperatures generated during the setting of ordinary Portland cement/simulant waste mixes can be significantly reduced by the use of a blend of ground granulated blast furnace slag and ordinary Portland cement. Laboratory and 220 litre trials using simulant wastes showed that the blended cement gave an improvement in properties of the cemented waste product, e.g. stability and reduction in leach rates compared with ordinary Portland cement formulations. A range of 220 litre scale mixing systems for the incorporation of liquid and solid wastes in cement was investigated. The work has confirmed that cement-based processes can be used for the immobilization of most types of low and medium level waste

  9. Leach characterization of cement encapsulated wastes

    International Nuclear Information System (INIS)

    Roy, D.M.; Scheetz, B.E.; Wakeley, L.D.; Barnes, M.W.

    1982-01-01

    Matrix encapsulation of defense nuclear waste as well as intermediate-level commercial wastes within a low-temperature cementitious composite were investigated. The cements for this study included both as-received and modified calcium silicate and calcium aluminate cements. Specimens were prepared following conventional formulation techniques designed to produce dense monoliths, followed by curing at 60 0 C. An alternative preparation procedure is contrasted in which the specimens were ''warm'' pressed in a uniaxial press at 150 0 C at 50,000 psi for 0.5 h. Specimens of the waste/cement composites were leached in deionized water following three different procedures which span a wide range of temperatures and solution saturation conditions. Aluminate and compositionally adjusted silicate cements exhibited a better retentivity for Cs and Sr than did the as-received silicate cement. 15 refs

  10. Study of commercial chemical additives for cementation of radioactive waste

    International Nuclear Information System (INIS)

    Mota Vieira, V.; Oliveira, C.C. de

    2015-01-01

    In this research it has been studied the effects of chemical additives (admixtures) in the cementation process of radioactive wastes, which are used to improve the properties of waste cementation process, both of the paste and of the solidified product. However there are a large variety of these materials that are frequently changed or taken out of the market, then it is essential to know the commercially available materials and their effects. The tests were carried out with a solution simulating the evaporator concentrate waste coming from PWR nuclear reactors. It was cemented using two formulations, A and B, incorporating higher or lower amount of waste, respectively. It was added chemical admixtures from two manufacturers (S and H), which were: accelerators, set retarders and superplasticizers. The experiments were organized by a factorial design 23. The measured parameters were the viscosity, the setting time, the paste and product density and the compressive strength. In this study we performed comparative analyzes of the results of compressive strength at age of 28 and 90 days and between the densities of the samples at the same ages. The compressive strength test at age of 28 days is considered a parameter essential issues related to security handling, transport and storage of cemented waste product. The results showed that the addition of accelerators improved the compressive strength of the cemented product, but presented lower values density products. (authors)

  11. Alkali-slag cements for the immobilization of radioactive wastes

    International Nuclear Information System (INIS)

    Shi, C.; Day, R.L.

    1996-01-01

    Alkali-slag cements consist of glassy slag and an alkaline activator and can show both higher early and later strengths than Type III Portland cement, if a proper alkaline activator is used. An examination of microstructure of hardened alkali-slag cement pastes with the help of XRD and SEM with EDAX shows that the main hydration product is C-S-H (B) with low C/S ratio and no crystalline substances exist such as Ca(OH) 2 , Al (OH) 3 and sulphoaluminates. Mercury intrusion tests indicate that hardened alkali-slag cement pastes have a lower porosity than ordinary Portland cement, and contain mainly gel pores. The fine pore structure of hardened alkali-slag cement pastes will restrict the ingress of deleterious substances and the leaching of harmful species such as radionuclides. The leachability of Cs + from hardened alkali-slag cement pastes is only half of that from hardened Portland cement. From all these aspects, it is concluded that alkali-slag cements are a better solidification matrix than Portland cement for radioactive wastes

  12. Corrosion of metal containers containing cemented radioactive wastes

    International Nuclear Information System (INIS)

    Duffo, G.S.; Farina, S.B.; Schulz, F.M.; Marotta, F

    2010-01-01

    Nuclear activities generate different kinds of radioactive wastes. In the case of Argentina, wastes classified as low and medium level are conditioned in metal drums for final disposal in a repository whose design is based on the use of multiple and independent barriers. Nuclear energy plants generate a large volume of mid-level radioactive wastes, consisting mainly of ion-exchange resins contaminated by fission products. Other contaminated products such as gloves, papers, clothing, rubber and plastic tubing, can be incinerated and the ashes from the combustion also constitute wastes that must be disposed of. These wastes (resins and ashes) must be immobilized in order to avoid the release of radionuclides into the environment. The wastes usually undergo a process of cementing to immobilize them. This work aims to systematically study the process of degradation by corrosion of the steel drums in contact with the cemented resins and with the ashes cemented with the addition of different types and concentrations of aggressive compounds (chloride and sulfate). The specimens are configured so that the parameters of interest for the steel in contact with the cemented materials can be measured. The variables of corrosion potential, electric resistivity of the matrix and polarization resistance (PR) were monitored and show that the presence of chloride increases the susceptibility to corrosion of the drum steel that is in contact with the cement resin matrix

  13. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    The substitution of alternative for fossil fuels in cement production has increased significantly in the last decade. Of these new alternative fuels, solid state fuels presently account for the largest part, and in particular, meat and bone meal, plastics and tyre derived fuels (TDF) accounted...... for the most significant alternative fuel energy contributors in the German cement industry. Solid alternative fuels are typically high in volatile content and they may differ significantly in physical and chemical properties compared to traditional solid fossil fuels. From the process point of view......, considering a modern kiln system for cement production, the use of alternative fuels mainly influences 1) kiln process stability (may accelerate build up of blockages preventing gas and/or solids flow), 2) cement clinker quality, 3) emissions, and 4) decreased production capacity. Kiln process stability...

  14. Acoustic monitoring techniques for corrosion degradation in cemented waste canisters

    International Nuclear Information System (INIS)

    Naish, C.C.; Buttle, D.; Wallace-Sims, R.; O'Brien, T.M.

    1991-01-01

    This report describes work to investigate acoustic emission as a non-intrusive monitor of corrosion and degradation of cemented wasteforms where the waste is a potentially reactive metal. The acoustic data collected shows good correlation with the corrosion rate as measured by hydrogen gas evolution rates and the electrochemically measured corrosion rates post cement hardening. The technique has been shown to be sensitive in detecting stress caused by expansive corrosion product within the cemented wasteform. The attenuation of the acoustic signal by the wasteform reduced the signal received by the monitoring equipment by a factor of 10 over a distance of approximately 150-400 mm, dependent on the water level in the cement. Full size packages were successfully monitored. It is concluded that the technique offers good potential for monitoring cemented containers of the more reactive metals, for example Magnox and aluminium. (author)

  15. Radioactive waste-Portland cement systems: I, radionuclide distribution

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Glasser, F.P.; Lachowski, E.E.

    1984-01-01

    Crystal chemical stabilization of radioactive wastes can be achieved during clinkering of, or with, ordinary portland cement. Waste loadings of 20 to 30 wt% are achieved by dilute solid solution of waste ions into cementitious host lattices. Higher waste loadings result in compatible noncementitious radiophases. The cementitious phases hydrate without loss of compressive strength. Crystallochemical relationships predict that the radionuclide partitioning in the anhydrous clinkered phases will be maintained in the hydration products. These cementitious hydroxylated radiophases would be in internal equilibrium under anticipated repository conditions. The radionuclide distributions observed are described in the context of established phase equilibria for commercial waste cement systems, but are applicable to transuranic, medium- and low-level wastes

  16. Waste management: products and services

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    A number of products and services related to radioactive waste management are described. These include: a portable cement solidification system for waste immobilization; spent fuel storage racks; storage and transport flasks; an on-site low-level waste storage facility; supercompactors; a mobile waste retrieval and encapsulation plant; underwater crushers; fuel assembly disposal; gaseous waste management; environmental restoration and waste management services; a waste treatment consultancy. (UK)

  17. Design and application of environmentally effective concrete with usage of chrysotile-cement waste

    Directory of Open Access Journals (Sweden)

    Egorova Lada

    2016-01-01

    Full Text Available Construction is resource-demanding industry, characterized by a large volume of waste. Particularly chrysotile cement waste obtained both in production and in dismantling over age chrysotile-cement products: corrugated asbestos boards and flat sheets, chrysotile-cement tubes. We propose to use dry chrysotile-cement waste as recycled aggregate for concrete. Based on developed compositions and identified properties of heavy concrete with chrysotile-cement waste introduce this technology to the production of foundation wall blocks. The studies confirmed the possibility of using chrysotile-cement aggregate and fine screening of crushing as a secondary coarse and fine aggregates for concrete with proper quality without increasing the cost of the product. Environmental safety of the obtained products was ensured. The direction for implementation of the research project was proposed.

  18. FY 1998 annual report on power generation by waste heat from cement production in China; Chugoku ni okeru cement hainetsu hatsuden 1998 nendo chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This project is to implement a feasibility study for applying waste heat power generation, which have been already commercialized in Japan and producing remarkable results, to China's cement plants producing 3,500 t/d or more of clinker, and thereby to try to establish a link with the Japan's clean development mechanism. It is expected that introduction of these systems improves energy use efficiency and environments in China. The study results indicate that the project for a Tongling Conch plant could generate power of 15,000 kW, reducing CO2 emissions by 89,178 t/y and cumulatively 1,783,560 tons in the 20-year period. The results also indicate that the project will be highly profitable, with an estimated internal return rate of as high as 33.78%. The project for a Huaxin plant could generate power of 8,400 kW, reducing CO2 emissions by 48,412 t/y and cumulatively 968,240 tons in the 20-year period, annually saving power charges by 325 million yen and bringing an internal return rate of 10.72%. (NEDO)

  19. Portland blended cements: demolition ceramic waste management

    International Nuclear Information System (INIS)

    Trezza, M.A.; Zito, S.; Tironi, A.; Irassar, E.F.; Rahhal, V.F.

    2017-01-01

    Demolition ceramic wastes (DCWs) were investigated in order to determine their potential use as supplementary cementitious materials in Portland Blended Cements (PBCs). For this purpose, three ceramic wastes were investigated. After characterization of the materials used, the effect of ceramic waste replacement (8, 24 and 40% by mass) was analyzed. Pozzolanic activity, hydration progress, workability and compressive strength were determined at 2, 7 and 28 days. The results showed that the ground wastes behave as filler at an early age, but as hydration progresses, the pozzolanic activity of ceramic waste contributes to the strength requirement. [es

  20. Statistical study of chemical additives effects in the waste cementation

    International Nuclear Information System (INIS)

    Tello, Cledola C.O. de; Diniz, Paula S.; Haucz, Maria J.A.

    1997-01-01

    This paper presents the statistical study, that was carried out to analyse the chemical additives effect in the waste cementation process. Three different additives from two industries were tested: set accelerator, set retarder and super plasticizers, in cemented pates with and without bentonite. The experiments were planned in accordance with the 2 3 factorial design, so that the effect of each type of additive, its quantity and manufacturer in cemented paste and specimens could be evaluated. The results showed that the use of these can improve the cementation process and the product. The admixture quantity and the association with bentonite were the most important factors affecting the process and product characteristics. (author). 4 refs., 9 figs., 4 tabs

  1. Research needs in cement-based waste forms

    International Nuclear Information System (INIS)

    McDaniel, E.W.; Spence, R.D.; Tallent, O.K.

    1990-01-01

    Cement-based waste forms are one of the most widely used waste disposal options, yet definitive knowledge of the fate of the waste species inside the waste form is lacking. A fundamental understanding of the chemistry and microstructure of the waste forms would lead to a better understanding of the mass transfer of the waste species, more confidence in predicting and extrapolating waste form performance, and design of better waste forms. Better and cheaper leach tests would lead to quicker and more cost effective screening of waste form alternatives. In addition, assessment of durability may be important to predicting waste form performance in the field. It should be noted that the research needs discussed in this report are from the perspective of investigators working in applied waste management areas, while the proposed investigations are fundamental or basic. Details as to experimental methods and tools to be used in achieving the objectives of the proposed are research beyond the scope of this paper and are better filled in by others. In broad terms, the research topics discussed are correlation of cement-based waste form physical properties to performance, waste-form fundamental chemistry and microstructure, and product performance testing

  2. Compressive strength test for cemented waste forms: validation process

    International Nuclear Information System (INIS)

    Haucz, Maria Judite A.; Candido, Francisco Donizete; Seles, Sandro Rogerio

    2007-01-01

    In the Cementation Laboratory (LABCIM), of the Development Centre of the Nuclear Technology (CNEN/CDTN-MG), hazardous/radioactive wastes are incorporated in cement, to transform them into monolithic products, preventing or minimizing the contaminant release to the environment. The compressive strength test is important to evaluate the cemented product quality, in which it is determined the compression load necessary to rupture the cemented waste form. In LABCIM a specific procedure was developed to determine the compressive strength of cement waste forms based on the Brazilian Standard NBR 7215. The accreditation of this procedure is essential to assure reproductive and accurate results in the evaluation of these products. To achieve this goal the Laboratory personal implemented technical and administrative improvements in accordance with the NBR ISO/IEC 17025 standard 'General requirements for the competence of testing and calibration laboratories'. As the developed procedure was not a standard one the norm ISO/IEC 17025 requests its validation. There are some methodologies to do that. In this paper it is described the current status of the accreditation project, especially the validation process of the referred procedure and its results. (author)

  3. The effectivity of bentonites in cesium retention of cemented waste products; Efetividade das bentonitas na retencao de cesio em produtos de rejeitos cimentados

    Energy Technology Data Exchange (ETDEWEB)

    Tello, Cledola Cassia Oliveira de

    2001-01-15

    The nuclear energy has been used for the human development in different areas, as in the medicine, in the agriculture, in the industry and in the environmental protection, besides the electricity generation. As in other activities, in the use of nuclear energy, residues are also generated. They are considered radioactive wastes when the contaminant content can bring a potential negative impact in the human health and in the environment. In this case they should be properly managed and should not be released without treatment. In general the waste processing consists in a volume reduction followed by solidification and/or conditioning. A number of materials can be considered as immobilisation matrices for the wastes, with the objective of maintain the radioactive material physical and chemically stable. The cement is extensively used because it is easy to obtain, there is large. experience in its use and the processing is done at room temperature. Many materials have been studied to improve the fixation characteristics of the radionuclides in the cemented product. The aim of this study was to search, among Brazilian natural materials, those that could be effective in the contaminant retention without jeopardising the process and other characteristics of the waste product. Four types of bentonite were selected to the process and product evaluation tests. Many mixtures were prepared with simulated waste, cement and bentonite in different proportions. The viscosity, set time, compressive strength and leaching were evaluated. In addition it was verified if the products were monolithic and without free water. Inactive caesium was used as tracer. The leaching resistance is the most important parameter in the product evaluation, because it indicates the retention capacity of the matrix for radionuclides when the product is in contact with the water. In 1985 leaching tests were begun and they have been continued till now and from their results it was proved that the

  4. Mechanisms and modelling of waste-cement and cement-host rock interactions

    Science.gov (United States)

    2017-06-01

    Safe and sustainable disposal of hazardous and radioactive waste is a major concern in today's industrial societies. The hazardous waste forms originate from residues of thermal treatment of waste, fossil fuel combustion and ferrous/non-ferrous metal smelting being the most important ones in terms of waste production. Low- and intermediate-level radioactive waste is produced in the course of nuclear applications in research and energy production. For both waste forms encapsulation in alkaline, cement-based matrices is considered to ensure long-term safe disposal. Cementitious materials are in routine use as industrial materials and have mainly been studied with respect to their evolution over a typical service life of several decades. Use of these materials in waste management applications, however, requires assessments of their performance over much longer time periods on the order of thousands to several ten thousands of years.

  5. Hospital waste ashes in Portland cement mortars

    International Nuclear Information System (INIS)

    Genazzini, C.; Zerbino, R.; Ronco, A.; Batic, O.; Giaccio, G.

    2003-01-01

    Nowadays, most concretes incorporate mineral additions such as pozzolans, fly ash, silica fume, blast furnace slag, and calcareous filler among others. Although the technological and economical benefits were the main reasons for the use of mineral additions, the prevention of environmental contamination by means of proper waste disposal becomes a priority. The chance of incorporating hospital waste ashes in Portland cement-based materials is presented here. Ash characterization was performed by chemical analysis, X-ray diffraction, radioactive material detection, and fineness and density tests. Conduction calorimetry and setting time tests were developed on pastes including ash contents from 0% to 100%. Mortars were prepared including ash contents up to 50% of cement. The results of setting time, temperature development, flexural and compressive strengths, water absorption, density, and leachability are analyzed. Results indicate that Portland cement systems could become an alternative for the disposal of this type of ashes

  6. Improved cement solidification of low and intermediate level radioactive wastes

    International Nuclear Information System (INIS)

    1993-01-01

    Cementation was the first and is still the most widely applied technique for the conditioning of low and intermediate level radioactive wastes. Compared with other solidification techniques, cementation is relatively simple and inexpensive. However, the quality of the final cemented waste forms depends very much on the composition of the waste and the type of cement used. Different kinds of cement are used for different kinds of waste and the compatibility of a specific waste with a specific cement type should always be carefully evaluated. Cementation technology is continuously being developed in order to improve the characteristics of cemented waste in accordance with the increasing requirements for quality of the final solidified waste. Various kinds of additives and chemicals are used to improve the cemented waste forms in order to meet all safety requirements. This report is meant mainly for engineers and designers, to provide an explanation of the chemistry of cementation systems and to facilitate the choice of solidification agents and processing equipment. It reviews recent developments in cementation technology for improving the quality of cemented waste forms and provides a brief description of the various cement solidification processes in use. Refs, figs and tabs

  7. Fixation of calcined waste by bituminization or cementation

    International Nuclear Information System (INIS)

    Napravnik, J.; Kyrs, M.; Ditl, P.

    1983-01-01

    The overall concept is given of the combination of calcination with fixation into bitumen, cement etc. The design is shown of a calciner with the capacity of 10 L/h which was tested on real radioactive wastes for 2000 h. The geometrical and operating parameters of the apparatus have been optimized based on a statistical evaluation of the experiments. Wastes containing nitrates are calcined at 300-550 deg. C, yielding oxides. Wastes containing sulphates, carbonates, KMnO 4 , or borates are calcined at 150-330 deg. C, yielding soluble salts. The content of H 3 BO 4 and Na 2 B 4 O 7 and in some cases of sulphates in the calcinate retards hardening of the mixture with cement. Nitrates and detergents also interfere. The effect of the above components on the products mixed with bitumen is much less. Detergents can be decomposed at 200-300 deg. C; organic acids can be reacted with A1 salts to form insoluble substances lowering the leaching rate of Sr and Cs; small amounts of SiO 2 eliminate the effect of borates on cement hardening. The drawbacks of bituminization with bitumen emulsions are the complicated preparation of the emulsion, higher leaching rate of the product and low stability of the emulsion against breaking. The leachability was determined (1-50 days) of different products containing LWR wastes: 33% of concentrated waste in cement of calcination product stabilized with PVA exhibit approx. 8x10 - 3 g/cm 2 per day, 33% of calcine in cement approx. 3x10 - 3 ; 40% concentrate fixed with bitumen emulsion approx. 9x10 - 4 ; 50% calcine stabilized with PVA in bitumen, pilot-plant scale approx. 2x10 - 5 ; the same but on a laboratory scale approx. 1.10 - 5 . (author)

  8. Cement-based processes for the immobilization of intermediate level radioactive waste

    International Nuclear Information System (INIS)

    Brown, D.J.; Lee, D.J.; Price, M.S.T.; Smith, D.L.G.

    1985-01-01

    Increasing attention is being paid to the use of cement-based materials for the immobilisation of intermediate level wastes. Various cementitious materials are surveyed and the use of blast furnace slag is shown to be advantageous. The properties of cemented wastes are surveyed both during processing and as solid products. The application of Winfrith Cementation Laboratory technology to plant and flowsheet development for Winfrith Reactor sludge immobilisation is described. (author)

  9. Feasibility of using ceramic furnace wastes in cement composites

    International Nuclear Information System (INIS)

    Fazzan, J.V.; Sanches, A.O.; Akasaki, J.L.; Malmonge, J.A.

    2016-01-01

    Currently, the region of Epitacio-SP President is classified as Paulista West Center in the production of ceramic tiles and bricks. However, as these industries have also generated environmental impacts in the production process with the generation of waste, the construction industries presents as great potential to absorb a large portion of these materials, called Pozzolans. In this sense, the research aims to study the characterization of Ceramic Furnace Wastes (CFC) and the evaluation of their reactivity. Mortar specimens were molded with different waste percentages in partial replacement of Portland cement, for analysis of compressive strength and capillary water absorption test. The characterization results show that important properties can be obtained by the preparation conditions of ashes, besides obtaining resistant activity index higher than expected by technical standards when using the material in replacement of Portland cement. (author)

  10. Study on cementation of simulated radioactive borated liquid wastes

    International Nuclear Information System (INIS)

    Sun Qina; Li Junfeng; Wang Jianlong

    2010-01-01

    To compare sulfoaluminate cement with ordinary Portland cement on their cementation of radioactive borated liquid waste and to provide more data for formula optimization, simulated radioactive borated liquid waste were solidified by the two cements. 28 d compressive strength and strength losses after water/freezing/irradiation resistance tests were investigated. Leaching test and X-ray diffraction analysis were also conducted. The results show that it is feasible to solidify borated liquid wastes with sulfoaluminate cement and ordinary Portland cement with formulas used in the study. The 28 d compressive strengths, strength losses after tests and simulated nuclides leaching rates of the solidified waste forms meet the demand of GB 14569.1-93. The sulfoaluminate cement formula show better retention of Cs + than ordinary Portland cement formula. Boron, in form of B (OH) 4 - , incorporate in ettringite as solid solutions. (authors)

  11. Polymer-Cement Composites Containing Waste Perlite Powder

    Directory of Open Access Journals (Sweden)

    Paweł Łukowski

    2016-10-01

    Full Text Available Polymer-cement composites (PCCs are materials in which the polymer and mineral binder create an interpenetrating network and co-operate, significantly improving the performance of the material. On the other hand, the need for the utilization of waste materials is a demand of sustainable construction. Various mineral powders, such as fly ash or blast-furnace slag, are successfully used for the production of cement and concrete. This paper deals with the use of perlite powder, which is a burdensome waste from the process of thermal expansion of the raw perlite, as a component of PCCs. The results of the testing of the mechanical properties of the composite and some microscopic observations are presented, indicating that there is a possibility to rationally and efficiently utilize waste perlite powder as a component of the PCC. This would lead to creating a new type of building material that successfully meets the requirements of sustainable construction.

  12. Essays of leaching in cemented products containing simulated waste from evaporator concentrated of PWR reactor; Ensaios de lixiviacao em produtos cimentados contendo rejeito simulado de concentrado do evaporador de reator PWR

    Energy Technology Data Exchange (ETDEWEB)

    Haucz, Maria Judite A.; Calabria, Jaqueline A. Almeida; Tello, Cledola Cassia O.; Candido, Francisco Donizete; Seles, Sandro Rogerio Novaes, E-mail: hauczmj@cdtn.b, E-mail: jaalmeida@cdtn.b, E-mail: tellocc@cdtn.b, E-mail: fdc@cdtn.b, E-mail: seless@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-10-26

    This paper evaluated the results from leaching resistance essays of cemented products, prepared from three distinct formulations, containing simulated waste of concentrated from the PWR reactor evaporator. The leaching rate is a parameter of qualification of solidified products containing radioactive waste and is determined in accordance with regulation ISO 6961. This procedure evaluates the capacity of transfer organic and inorganic substances presents in the waste through dissolution in the extractor medium. For the case of radioactive waste it is reached the more retention of contaminants in the cemented product, i.e.the lesser value of lixiviation rate. Therefore, this work evaluated among the proposed formulation that one which attend the criterion established in the regulation CNEN-NN-6.09

  13. Centralized cement solidification technique for low-level radioactive wastes

    International Nuclear Information System (INIS)

    Matsuda, Masami; Nishi, Takashi; Izumida, Tatsuo; Tsuchiya, Hiroyuki.

    1996-01-01

    A centralized cement solidification system has been developed to enable a single facility to solidify such low-level radioactive wastes as liquid waste, spent ion exchange resin, incineration ash, and miscellaneous solid wastes. Since the system uses newly developed high-performance cement, waste loading is raised and deterioration of waste forms after land burial prevented. This paper describes the centralized cement solidification system and the features of the high-performance cement. Results of full-scale pilot plant tests are also shown from the viewpoint of industrial applicability. (author)

  14. Optimization and characterization of a cemented ultimate-storage product

    Science.gov (United States)

    Brunner, H.

    1981-12-01

    The U- and Pu-containing packaging wastes can be homogeneously cemented after a washing and fragmentation process. Both finely crushed and coarsely fragmented raw wastes yield products with sufficient mechanical stability. The processability limit of the coarsely fragmented raw waste using cement paste or mortar is largely determined by the cellulose content, which is not to exceed 1.3% by weight in the end waste. Of 9 binders studied, the most corrosion-resistant products were obtained with blast-furnace slag cement, whereas poured concrete and Maxit are much less resistant in five-component brine. In the cemented product, hydrolysis of plasticizers (DOP) from plastics (PVC) occurs, leading to release of 2-ethyl-hexanol. This reaction occurs to a much lower degree with blast-furnace slag cement than with all other binders studied. The binder chosen for further tests consists of blast-furnace slag cement, concrete fluidizer and a stabilizer, and is processed at a W/C ratio of 0.43.

  15. Comparative life cycle analysis of cement made with coal vs hazardous waste as fuel

    International Nuclear Information System (INIS)

    Kelly, K.E.; Beeh, J.

    1994-01-01

    The purpose of this life cycle analysis (LCA) is to compare the life cycle of cement made with coal, the standard fuel used in a cement kiln, versus cement made with hazardous waste-derived fuels. The intent of the study is to determine whether the use of hazardous waste as a fuel in the production of cement could result in an increase in detrimental effects to either health or environment. Those evaluated for potential adverse effect include cement kiln workers, waste transporters, and consumers using the final product for private use. The LCA stages included all the processes involved with cement, including raw materials acquisition, transportation, manufacturing, packaging, distribution, use, recycling, and disposal. The overall conclusions of the LCA are that use of waste fuels instead of coal to make cement: (1) does not increase, and may reduce, the concentration of contaminants in the cement product due to the reduction or elimination of the use of coal; (2) reduces or eliminates use of non-renewable fossil fuels, such as coal, as well as the environmental damage and impacts associated with coal mining; (3) provides a more environmentally beneficial means of destroying many types of wastes than alternative treatment methods, including incineration, thus decreasing the need for waste treatment facilities and capacity; (4) decreases overall emissions during transportation but may increase the overall consequences of accidents or spills; (5) results in cement product which may be packaged, transported, distributed and used in the same manner as cement product made with coal; (6) lowers the cost of cement production; and (7) overall appears to result in less health and environmental impacts

  16. Overview of waste stabilization with cement.

    Science.gov (United States)

    Batchelor, B

    2006-01-01

    Cement can treat a variety of wastes by improving physical characteristics (solidification) and reducing the toxicity and mobility of contaminants (stabilization). Potentially adverse waste-binder interactions are an important consideration because they can limit solidification. Stabilization occurs when a contaminant is converted from the dissolved (mobile) phase to a solid (immobile) phase by reactions, such as precipitation, sorption, or substitution. These reactions are often strongly affected by pH, so the presence of components of the waste that control pH are critical to stabilization reactions. Evaluating environmental impacts can be accomplished in a tiered strategy in which simplest approach would be to measure the maximum amount of contaminant that could be released. Alternatively, the sequence of release can be determined, either by microcosm tests that attempt to simulate conditions in the disposal zone or by mechanistic models that attempt to predict behavior using fundamental characteristics of the treated waste.

  17. Increased Coal Replacement in a Cement Kiln Burner by Feeding a Mixture of Solid Hazardous Waste and Shredded Plastic Waste

    OpenAIRE

    Ariyaratne, W. K. Hiromi; Melaaen, Morten Christian; Tokheim, Lars-André

    2013-01-01

    The present study aims to find the maximum possible replacement of coal by combined feeding of plastic waste and solid hazardous waste mixed with wood chips (SHW) in rotary kiln burners used in cement kiln systems. The coal replacement should be achieved without negative impacts on product quality, emissions or overall operation of the process. A full-scale experiment was carried out in the rotary kiln burner of a cement kiln by varying SHW and plastic waste feeding rates. Experimental result...

  18. Concrete and cement composites used for radioactive waste deposition.

    Science.gov (United States)

    Koťátková, Jaroslava; Zatloukal, Jan; Reiterman, Pavel; Kolář, Karel

    2017-11-01

    This review article presents the current state-of-knowledge of the use of cementitious materials for radioactive waste disposal. An overview of radwaste management processes with respect to the classification of the waste type is given. The application of cementitious materials for waste disposal is divided into two main lines: i) as a matrix for direct immobilization of treated waste form; and ii) as an engineered barrier of secondary protection in the form of concrete or grout. In the first part the immobilization mechanisms of the waste by cement hydration products is briefly described and an up-to date knowledge about the performance of different cementitious materials is given, including both traditional cements and alternative binder systems. The advantages, disadvantages as well as gaps in the base of information in relation to individual materials are stated. The following part of the article is aimed at description of multi-barrier systems for intermediate level waste repositories. It provides examples of proposed concepts by countries with advanced waste management programmes. In the paper summary, the good knowledge of the material durability due to its vast experience from civil engineering is highlighted however with the urge for specific approach during design and construction of a repository in terms of stringent safety requirements. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Characteristics of Cement Solidification of Metal Hydroxide Waste

    Directory of Open Access Journals (Sweden)

    Dae-Seo Koo

    2017-02-01

    Full Text Available To perform the permanent disposal of metal hydroxide waste from electro-kinetic decontamination, it is necessary to secure the technology for its solidification. The integrity tests on the fabricated solidification should also meet the criteria of the Korea Radioactive Waste Agency. We carried out the solidification of metal hydroxide waste using cement solidification. The integrity tests such as the compressive strength, immersion, leach, and irradiation tests on the fabricated cement solidifications were performed. It was also confirmed that these requirements of the criteria of Korea Radioactive Waste Agency on these cement solidifications were met. The microstructures of all the cement solidifications were analyzed and discussed.

  20. Characteristics of cement solidification of metal hydroxide waste

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae Seo; Sung, Hyun Hee; Kim, Seung Soo; Kim, Gye Nam; Choi, Jong Won [Dept. of Decontemination Decommission Technology Development, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-02-15

    To perform the permanent disposal of metal hydroxide waste from electro-kinetic decontamination, it is necessary to secure the technology for its solidification. The integrity tests on the fabricated solidification should also meet the criteria of the Korea Radioactive Waste Agency. We carried out the solidification of metal hydroxide waste using cement solidification. The integrity tests such as the compressive strength, immersion, leach, and irradiation tests on the fabricated cement solidifications were performed. It was also confirmed that these requirements of the criteria of Korea Radioactive Waste Agency on these cement solidifications were met. The microstructures of all the cement solidifications were analyzed and discussed.

  1. Ordinary Portland Cement matrix for solidification of cellulosic protective clothes hazardous wastes

    International Nuclear Information System (INIS)

    Shatta, H.A.; Saleh, H.M.

    2006-01-01

    The used cellulosic protective clothes constitutes considerable fraction of the hazardous and radioactive wastes accumulated during the practical daily life. The direct solidification of these wastes with ordinary Portland cement resulted in waste forms having undesired characters, therefore, it is recommended to immobilize the secondary waste solutions coming from the oxidative degradation of the used protective clothes waste simulates rather than direct imbedding. IR analyses, X-ray diffraction and thermal characteristics for products of both direct encapsulation of the waste and the cementation of its degradation products were performed to evaluate the properties of the final waste cemented form before their disposal. Based on the results reached from X-ray diffraction, IR spectrograms and thermal analyses reports, it could be stated that no detectable changes in hydration and curing coarse of ordinary Portland cement when mixing the residual secondary waste solution resulting from the oxidative degradation of the used protective clothes waste simulate compared with mixing cement with water and in reverse with imbedding the unprocessed waste in cement matrix

  2. LEACHING BOUNDARY IN CEMENT-BASED WASTE FORMS

    Science.gov (United States)

    Cement-based fixation systems are among the most commonly employed stabilization/solidification techniques. These cement haste mixtures, however, are vulnerable to ardic leaching solutions. Leaching of cement-based waste forms in acetic acid solutions with different acidic streng...

  3. Identifying improvement potentials in cement production with life cycle assessment.

    Science.gov (United States)

    Boesch, Michael Elias; Hellweg, Stefanie

    2010-12-01

    Cement production is an environmentally relevant process responsible for 5% of total anthropogenic carbon dioxide emissions and 7% of industrial fuel use. In this study, life cycle assessment is used to evaluate improvement potentials in the cement production process in Europe and the USA. With a current fuel substitution rate of 18% in Europe and 11% in the USA, both regions have a substantial potential to reduce greenhouse gas emissions and save virgin resources by further increasing the coprocessing of waste fuels. Upgrading production technology would be particularly effective in the USA where many kiln systems with very low energy efficiency are still in operation. Using best available technology and a thermal substitution rate of 50% for fuels, greenhouse gas emissions could be reduced by 9% for Europe and 18% for the USA per tonne of cement. Since clinker production is the dominant pollution producing step in cement production, the substitution of clinker with mineral components such as ground granulated blast furnace slag or fly ash is an efficient measure to reduce the environmental impact. Blended cements exhibit substantially lower environmental footprints than Portland cement, even if the substitutes feature lower grindability and require additional drying and large transport distances. The highest savings in CO(2) emissions and resource consumption are achieved with a combination of measures in clinker production and cement blending.

  4. Determination of quality standard of cemented radioactive wastes

    International Nuclear Information System (INIS)

    Johan, B.

    1997-01-01

    The standard determination of cemented low activity radioactive waste has been carried out. This study was intended to find the quality of immobilized product as a guaranty to the public and the environmental safety. As preliminary study, there parameters type have been studied i.e, the density, compressive strength and the leaching rate. By adopted the formulations of advanced country and field data, it can be concluded that the cementation waste should have the density, p, between 1.70 and 2.50 g.cm - 3, the compressive strength, S, between 20 and 50 N.mm - 2, the leaching rates R n between 1.70 x 10 - 2 and 2.50 x 10 - 3 g.cm - 2.day - 1 and after 150 days leaching time the leaching rate R n - 3 g.cm - 2.day - 1. This study is expected to be used to propose the Indonesian National Standard (INS) (author)

  5. Immobilization of radioactive waste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, S.; Atkins, M.; Beckley, N.; Carson, S.

    1986-11-01

    Experimental and theoretical studies of hydrated cement systems are described. The behaviour of slag-based cement is described with a view to predicting their long term pH, Esub(n) and mineralogical balance. Modelling studies which enable the prediction at long ages of cement composites are advanced and a base model of the CaO-SiO 2 -H 2 O system presented. The behaviour of U and I in cements is explored. The tolerance of cement systems for a wide range of miscellaneous waste stream components and environmental hazards is described. The redox potential in cements is effectively lowered by irradiation. (author)

  6. Immobilisation of shredded waste in a cement matrix

    International Nuclear Information System (INIS)

    James, J.M.; Smith, D.L.

    1987-10-01

    The work covered in the period of this report was aimed at proving the infilling capabilities of waste packages containing shredded paper and plastic simulant waste material held in a basket. The programme required the production of 200 and 500 litre packages and a demonstration that infilling could be attained to give a minimum of voidage in the completed cemented product. The procurement, testing and fitting of level detectors was an important part of this work to demonstrate a means of controlling the process to prevent overfilling of the packages. Evaluation of full-scale cemented products was required to confirm previously reported properties of density and homogeneity in packages produced by the reference encapsulation process and to demonstrate package integrity under sea-disposal conditions. A standard feedstock for the continuity of a long-term programme was required. Such a product, based on an analysis of arisings from plutonium gloveboxes, was produced in bulk and characterised. The previously observed movement of waste during infilling, due to its low density compared with that of the infill grout, required further assessment. During the period, 200, 400 and 500 litre drums required for future active infilling trials were modified and despatched to AERE Harwell for waste loading. These drums were fitted with level detectors and with grout spreader troughs which had been identified during the development programme. A prototype automated Grout Infill Test Rig designed by BNF plc was delivered to Winfrith towards the end of the period for practical assessment trials. (author)

  7. The concept of 'end of waste' and recycling of hazardous materials: in depth characterization of the product of thermal transformation of cement-asbestos

    Czech Academy of Sciences Publication Activity Database

    Croce, A.; Allegrina, M.; Trivero, P.; Rinaudo, C.; Viani, Alberto; Pollastri, S.; Gualtieri, A. F.

    2014-01-01

    Roč. 78, č. 5 (2014), s. 1177-1191 ISSN 0026-461X R&D Projects: GA MŠk(CZ) LO1219 Keywords : end of waste * secondary raw material * cement -asbestos * thermal transformation Subject RIV: JN - Civil Engineering Impact factor: 2.026, year: 2014 http://minmag.geoscienceworld.org/content/78/5/1177.abstract

  8. Influence of chemical composition of civil construction waste in the cement paste

    International Nuclear Information System (INIS)

    Cunha, G.A.; Andrade, A.C.D.; Souza, J.M.M.; Evangelista, A.C.J.; Almeida, V.C.

    2009-01-01

    The construction and demolition waste when disposed inappropriately might cause serious public health problems. Its reutilization focusing on the development of new products using simple production techniques, assuring a new product life cycle and not damaging the environment is inserted in sustainable concept. The aim of this work was identifying the characteristics of types of waste generated in a residential reform (glassy ceramic and fill dirt leftovers) verifying separately its influence on cement pastes mechanical behavior. Cement pastes + wastes were prepared in 25% and 50% proportions with an approximately 0,35 water/cement relation and, glue time determination, water absorption, resistance to compression and X-ray fluorescence assays were taken. The results indicate that the chemical composition of the waste causes changes in the behavior of cement pastes, reflecting on their resistance to compression. (author)

  9. Establishment of cementation parameters of dried waste from evaporation coming from NPP operation

    International Nuclear Information System (INIS)

    Faria, Érica R.; Tello, Clédola C.O.; Costa, Bruna S.

    2017-01-01

    The radioactive wastes generated in Brazil are treated and sent to initial and intermediate storages. The 'Project RBMN' proposes the implantation of the Brazilian repository to receive and permanently dispose the low and intermediate level radioactive wastes. The CNEN NN 6.09 standard - Acceptance Criteria for Disposal of Low and Intermediate Radioactive Wastes (LIRW) - establishes the fundamental requirements to accept the wastes packages in the repository. The evaporator concentrate is one of liquid wastes generated in a Nuclear Power Plant (NPP) operation and usually it is cemented directly inside the packing. The objective of this research is to increase the amount of the incorporated waste in each package, using the drying process before the cementation, consequently reducing the volume of the waste to be disposed. Drying and cementation parameters were established in order to scale-up the process aiming at waste products that comply with the requirements of CNEN standard. The cementation of the resulting dry wastes was carried out with different formulations, varying the amount of cement, dry waste and water. These tests were analyzed in order to select the best products, with higher waste incorporation than current process and its complying the requirements of the standard CNEN NN 6.09. (author)

  10. Establishment of cementation parameters of dried waste from evaporation coming from NPP operation

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Érica R.; Tello, Clédola C.O., E-mail: erica.engqui@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte/MG (Brazil); Costa, Bruna S., E-mail: brusilveirac@gmail.com [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil)

    2017-07-01

    The radioactive wastes generated in Brazil are treated and sent to initial and intermediate storages. The 'Project RBMN' proposes the implantation of the Brazilian repository to receive and permanently dispose the low and intermediate level radioactive wastes. The CNEN NN 6.09 standard - Acceptance Criteria for Disposal of Low and Intermediate Radioactive Wastes (LIRW) - establishes the fundamental requirements to accept the wastes packages in the repository. The evaporator concentrate is one of liquid wastes generated in a Nuclear Power Plant (NPP) operation and usually it is cemented directly inside the packing. The objective of this research is to increase the amount of the incorporated waste in each package, using the drying process before the cementation, consequently reducing the volume of the waste to be disposed. Drying and cementation parameters were established in order to scale-up the process aiming at waste products that comply with the requirements of CNEN standard. The cementation of the resulting dry wastes was carried out with different formulations, varying the amount of cement, dry waste and water. These tests were analyzed in order to select the best products, with higher waste incorporation than current process and its complying the requirements of the standard CNEN NN 6.09. (author)

  11. Quality control of radioactive waste products

    International Nuclear Information System (INIS)

    Martens, B.R.; Warnecke, E.; Odoj, R.

    1986-01-01

    The variety of incoming untreated wastes, treatment methods, waste forms and containers requires a great variety of controlling methods and principles to be applied both during waste treatment and on the final product. The paper describes product control schemes and methods, sampling systems and transportable testing equipment for waste drums, and equipment for waste cementation using in-drum stirring and subsequent fixation of solid wastes in the flowable product. (DG) [de

  12. Solidification of ion exchange resin wastes in hydraulic cement

    International Nuclear Information System (INIS)

    Neilson, R.M. Jr.; Kalb, P.; Fuhrmann, M.; Colombo, P.

    1982-01-01

    Work has been conducted to investigate the solidification of ion exchange resin wastes with portland cements. These efforts have been directed toward the development of acceptable formulations for the solidification of ion exchange resin wastes and the characterization of the resultant waste forms. This paper describes formulation development work and defines acceptable formulations in terms of ternary phase compositional diagrams. The effects of cement type, resin type, resin loading, waste/cement ratio and water/cement ratio are described. The leachability of unsolidified and solidified resin waste forms and its relationship to full-scale waste form behavior is discussed. Gamma irradiation was found to improve waste form integrity, apparently as a result of increased resin crosslinking. Modifications to improve waste form integrity are described. 3 tables

  13. Solidification of low-level radioactive wastes in masonry cement

    International Nuclear Information System (INIS)

    Zhou, H.; Colombo, P.

    1987-03-01

    Portland cements are widely used as solidification agents for low-level radioactive wastes. However, it is known that boric acid wastes, as generated at pressurized water reactors (PWR's) are difficult to solidify using ordinary portland cements. Waste containing as little as 5 wt % boric acid inhibits the curing of the cement. For this purpose, the suitability of masonry cement was investigated. Masonry cement, in the US consists of 50 wt % slaked lime (CaOH 2 ) and 50 wt % of portland type I cement. Addition of boric acid in molar concentrations equal to or less than the molar concentration of the alkali in the cement eliminates any inhibiting effects. Accordingly, 15 wt % boric acid can be satisfactorily incorporated into masonry cement. The suitability of masonry cement for the solidification of sodium sulfate wastes produced at boiling water reactors (BWR's) was also investigated. It was observed that although sodium sulfate - masonry cement waste forms containing as much as 40 wt % Na 2 SO 4 can be prepared, waste forms with more than 7 wt % sodium sulfate undergo catastrophic failure when exposed to an aqueous environment. It was determined by x-ray diffraction that in the presence of water, the sulfate reacts with hydrated calcium aluminate to form calcium aluminum sulfate hydrate (ettringite). This reaction involves a volume increase resulting in failure of the waste form. Formulation data were identified to maximize volumetric efficiency for the solidification of boric acid and sodium sulfate wastes. Measurement of some of the waste form properties relevant to evaluating the potential for the release of radionuclides to the environment included leachability, compression strengths and chemical interactions between the waste components and masonry cement. 15 refs., 19 figs., 9 tabs

  14. Modelling the effects of waste components on cement hydration

    NARCIS (Netherlands)

    van Eijk, R.J.; Brouwers, Jos

    2000-01-01

    Ordinary Portland Cement (OPC) is often used for the Solidification/Stabilization (S/S) of waste containing heavy metals and salts. These waste componenents will precipitate in the form of insoluble compounds onto unreacted cement clinker grains preventing further hydration. In this study the long

  15. Properties of backfilling material for solidifying miscellaneous waste using recycled cement from waste concrete

    International Nuclear Information System (INIS)

    Matsuda, Atsuo; Yamamoto, Kazuo; Konishi, Masao; Iwamoto, Yoshiaki; Yoshikane, Toru; Koie, Toshio; Nakashima, Yoshio.

    1997-01-01

    A large reduction of total radioactive waste is expected, if recycled cement from the waste concrete of decommissioned nuclear power plants would be able to be used the material for backfilling mortar among the miscellaneous waste. In this paper, we discuss the hydration, strength and consistency of recycled cement compared with normal portland cement. The strength of recycled cement mortar is lower than that of normal portland cement mortar on the same water to cement ratio. It is possible to obtain the required strength to reduce the water to cement ratio by using of high range water-reducing AE agent. According to reducing of water to cement ratio, the P-type funnel time of mortar increase with the increase of its viscosity. However, in new method of self-compactability for backfilling mortar, it became evident that there was no difference between the recycled cement and normal portland cement on the self-compactability. (author)

  16. Solidification of radioactive waste in a cement/lime mixture

    International Nuclear Information System (INIS)

    Zhou, H.; Colombo, P.

    1984-01-01

    The suitability of a cement/lime mixture for use as a solidification agent for different types of wastes was investigated. This work includes studies directed towards determining the wasted/binder compositional field over which successful solidification occurs with various wastes and the measurement of some of the waste from properties relevant to evaluating the potential for the release of radionuclides to the environment. In this study, four types of low-level radioactive wastes were simulated for incorporation into a cement/lime mixture. These were boric acid waste, sodium sulfate wastes, aion exchange resins and incinerator ash. 7 references, 3 figures, 2 tables

  17. A Thermoelectric Waste-Heat-Recovery System for Portland Cement Rotary Kilns

    Science.gov (United States)

    Luo, Qi; Li, Peng; Cai, Lanlan; Zhou, Pingwang; Tang, Di; Zhai, Pengcheng; Zhang, Qingjie

    2015-06-01

    Portland cement is produced by one of the most energy-intensive industrial processes. Energy consumption in the manufacture of Portland cement is approximately 110-120 kWh ton-1. The cement rotary kiln is the crucial equipment used for cement production. Approximately 10-15% of the energy consumed in production of the cement clinker is directly dissipated into the atmosphere through the external surface of the rotary kiln. Innovative technology for energy conservation is urgently needed by the cement industry. In this paper we propose a novel thermoelectric waste-heat-recovery system to reduce heat losses from cement rotary kilns. This system is configured as an array of thermoelectric generation units arranged longitudinally on a secondary shell coaxial with the rotary kiln. A mathematical model was developed for estimation of the performance of waste heat recovery. Discussions mainly focus on electricity generation and energy saving, taking a Φ4.8 × 72 m cement rotary kiln as an example. Results show that the Bi2Te3-PbTe hybrid thermoelectric waste-heat-recovery system can generate approximately 211 kW electrical power while saving 3283 kW energy. Compared with the kiln without the thermoelectric recovery system, the kiln with the system can recover more than 32.85% of the energy that used to be lost as waste heat through the kiln surface.

  18. Radiobiological waste treatment-ashing treatment and immobilization with cement

    Energy Technology Data Exchange (ETDEWEB)

    Shengtao, Feng; Li, Gong; Li, Cheng; Benli, Wang; Lihong, Wang [China Inst. for Radiation Protection, Taiyuan, Shanxi (China)

    1997-02-01

    This report describes the results of the study on the treatment of radioactive biological waste in the China Institute for Radiation Protection (CIRP). The possibility of radiobiological waste treatment was investigated by using a RAF-3 type rapid ashing apparatus together with the immobilization of the resulted ash. This rapid ashing apparatus, developed by CIRP, is usually used for pretreatment of samples prior to chemical analysis and physical measurements. The results show that it can ash 3 kg of animal carcasses a batch, the ashing time is 5-7 h and the ash content is less than 4 wt%. The ashing temperature not exceeding 450 deg. C was used without any risk of high losses of radionuclides. The ash from the rapid ashing apparatus was demonstrated to be immobilized with ordinary silicate cement. The optimum cement/ash/water formulation of the cemented waste form was 35 {+-} 5 wt% cement, 29 {+-} 2 wt% water, and 36 {+-} 6 wt% ash. The performance of the waste form was in compliance with the technical requirements except for impact resistance. Mixing additives in immobilization formulations can improve the performance of the cemented ash waste form. The additives chosen were DH{sub 4A} flow promoter as a cement additive and vermiculite or zeolite as a supplement. The recommended formulation, i.e. an improved formulation of the cemented ash waste form is that additives DH{sub 4A} flow promoter and vermiculite (or zeolite) are added on the ground of optimum cement/ash/water formulation of the cemented waste form, the dosage of water, DH{sub 4A} and vermiculite (or zeolite) is 70 wt%, 0.5 wt% and {<=} 5 wt% of the cement dosage, respectively. The cemented ash waste forms obtained meet all the requirements for disposal. (author). 12 refs, 7 figs, 13 tabs.

  19. Radiobiological waste treatment-ashing treatment and immobilization with cement

    International Nuclear Information System (INIS)

    Feng Shengtao; Gong Li; Cheng Li; Wang Benli; Wang Lihong

    1997-01-01

    This report describes the results of the study on the treatment of radioactive biological waste in the China Institute for Radiation Protection (CIRP). The possibility of radiobiological waste treatment was investigated by using a RAF-3 type rapid ashing apparatus together with the immobilization of the resulted ash. This rapid ashing apparatus, developed by CIRP, is usually used for pretreatment of samples prior to chemical analysis and physical measurements. The results show that it can ash 3 kg of animal carcasses a batch, the ashing time is 5-7 h and the ash content is less than 4 wt%. The ashing temperature not exceeding 450 deg. C was used without any risk of high losses of radionuclides. The ash from the rapid ashing apparatus was demonstrated to be immobilized with ordinary silicate cement. The optimum cement/ash/water formulation of the cemented waste form was 35 ± 5 wt% cement, 29 ± 2 wt% water, and 36 ± 6 wt% ash. The performance of the waste form was in compliance with the technical requirements except for impact resistance. Mixing additives in immobilization formulations can improve the performance of the cemented ash waste form. The additives chosen were DH 4A flow promoter as a cement additive and vermiculite or zeolite as a supplement. The recommended formulation, i.e. an improved formulation of the cemented ash waste form is that additives DH 4A flow promoter and vermiculite (or zeolite) are added on the ground of optimum cement/ash/water formulation of the cemented waste form, the dosage of water, DH 4A and vermiculite (or zeolite) is 70 wt%, 0.5 wt% and ≤ 5 wt% of the cement dosage, respectively. The cemented ash waste forms obtained meet all the requirements for disposal. (author). 12 refs, 7 figs, 13 tabs

  20. Use of waste brick as a partial replacement of cement in mortar.

    Science.gov (United States)

    Naceri, Abdelghani; Hamina, Makhloufi Chikouche

    2009-08-01

    The aim of this study is to investigate the use of waste brick as a partial replacement for cement in the production of cement mortar. Clinker was replaced by waste brick in different proportions (0%, 5%, 10%, 15% and 20%) by weight for cement. The physico-chemical properties of cement at anhydrous state and the hydrated state, thus the mechanical strengths (flexural and compressive strengths after 7, 28 and 90 days) for the mortar were studied. The microstructure of the mortar was investigated using scanning electron microscopy (SEM), the mineralogical composition (mineral phases) of the artificial pozzolan was investigated by the X-ray diffraction (XRD) and the particle size distributions was obtained from laser granulometry (LG) of cements powders used in this study. The results obtained show that the addition of artificial pozzolan improves the grinding time and setting times of the cement, thus the mechanical characteristics of mortar. A substitution of cement by 10% of waste brick increased mechanical strengths of mortar. The results of the investigation confirmed the potential use of this waste material to produce pozzolanic cement.

  1. Use of waste brick as a partial replacement of cement in mortar

    International Nuclear Information System (INIS)

    Naceri, Abdelghani; Hamina, Makhloufi Chikouche

    2009-01-01

    The aim of this study is to investigate the use of waste brick as a partial replacement for cement in the production of cement mortar. Clinker was replaced by waste brick in different proportions (0%, 5%, 10%, 15% and 20%) by weight for cement. The physico-chemical properties of cement at anhydrous state and the hydrated state, thus the mechanical strengths (flexural and compressive strengths after 7, 28 and 90 days) for the mortar were studied. The microstructure of the mortar was investigated using scanning electron microscopy (SEM), the mineralogical composition (mineral phases) of the artificial pozzolan was investigated by the X-ray diffraction (XRD) and the particle size distributions was obtained from laser granulometry (LG) of cements powders used in this study. The results obtained show that the addition of artificial pozzolan improves the grinding time and setting times of the cement, thus the mechanical characteristics of mortar. A substitution of cement by 10% of waste brick increased mechanical strengths of mortar. The results of the investigation confirmed the potential use of this waste material to produce pozzolanic cement.

  2. Radioactive wastes dispersed in stabilized ash cements

    International Nuclear Information System (INIS)

    Rubin, J.B.; Taylor, C.M.V.; Sivils, L.D.; Carey, J.W.

    1997-01-01

    One of the most widely-used methods for the solidification/stabilization of low-level radwaste is by incorporation into Type-I/II ordinary portland cement (OPC). Treating of OPC with supercritical fluid carbon dioxide (SCCO 2 ) has been shown to significantly increase the density, while simultaneously decreasing porosity. In addition, the process significantly reduces the hydrogenous content, reducing the likelihood of radiolytic decomposition reactions. This, in turn, permits increased actinide loadings with a concomitant reduction in disposable waste volume. In this article, the authors discuss the combined use of fly-ash-modified OPC and its treatment with SCCO 2 to further enhance immobilization properties. They begin with a brief summary of current cement immobilization technology in order to delineate the areas of concern. Next, supercritical fluids are described, as they relate to these areas of concern. In the subsequent section, they present an outline of results on the application of SCCO 2 to OPC, and its effectiveness in addressing these problem areas. Lastly, in the final section, they proffer their thoughts on why they believe, based on the OPC results, that the incorporation of fly ash into OPC, followed by supercritical fluid treatment, can produce highly efficient wasteforms

  3. Utilization of the national Portland cement for immobilizing radioactive wastes - Physical characteristics

    International Nuclear Information System (INIS)

    Rzyski, B.M.; Suarez, A.A.

    1988-01-01

    This paper shows the results obtained in the study of the national Portland cement, P320, as matrix for radioactive nitric waste incorporation. Cement use practice in other countries is common for this purposes and demonstrates to be cheap and accessible when low and medium level wastes are immobilized. Some of physical characteristics as: homogeneity,mechanical strenght, setting and porosity are analysed due to water-cement ratio and salt contents. Those characteristics which are proper of the final product, must be controlled in such way to assure a long time integrity of the wasteform. The establishment of process and quality control criteria are based in such kind of data. (author) [pt

  4. Cementation of wastes with boric acid; Cimentacao de rejeitos contendo acido borico

    Energy Technology Data Exchange (ETDEWEB)

    Tello, Cledola C.O.; Haucz, Maria Judite A. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Alves, Lilian J.L.; Oliveira, Arno H. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2000-07-01

    In nuclear power plants (PWR) are generated wastes, such as concentrate, which comes from the evaporation of liquid radioactive wastes, and spent resins. Both have boron in their composition. The cementation process is one of the options to solidify these wastes, but the boron has a negative effect on the setting of the cement mixture. In this paper are presented the experiments that are being carried out in order to overcome this problem and also to improve the efficiency of the process. Simulated wastes were cemented using additives (clays, admixtures etc.). In the process and product is being evaluated the effect of the amount, type and addition order of the materials. The mixtures were selected in accordance with their workability and incorporated waste. The solidified products are monolithic without free water with a good mechanical resistance. (author)

  5. Immobilization of radioactive waste in cement-based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Crawford, R.W.; McCulloch, C.E.; Angus, M.J.

    1984-01-01

    Tobermorite and xonotlite, two synthetic calcium silicate hydrates, improve the Cs retention of cement matrices for Cs, when incorporated at the 6 to 10% level. A kinetic and mechanistic scheme is presented for the reaction of fine grained, Cs-loaded clinoptilolite with cement. The Magnox waste form reacts quickly with cement, leading to an exchange of carbonate between waste form and cement components. Carbonation of cements leads to a marked improvement in their physical properties of Cs retentivity. Diffusion models are presented for cement systems whose variable parameters can readily be derived from experimental measurements. Predictions about scaled-up behaviour of large immobilized masses are applied to extrapolation of laboratory scale results to full-size masses. (author)

  6. Physical and mechanical properties of cement mortar made with brick waste

    Directory of Open Access Journals (Sweden)

    Mohamed Guendouz

    2018-01-01

    Full Text Available The development of new building materials is a current problem where researchers are trying to find the right materials for each region and returning cheapest countries. Recycling and recovery of waste are now considered as a promising solution to meet the deficit between production and consumption and protecting the environment. This work focused on the study of the effect of brick waste in the production of cement mortar with substitution rates ranging from 5-30% by weight of cement and to compare its performance with fresh and hardened state with ordinary mortar considered as control mortar. Compressive and tensile strengths up to 28 days of age were compared with those of controlled mortar. Water absorption was also measured at 28 days of age. The test results indicate the beneficial effect of brick waste powder on performance of cement mortar with an optimum of 15% of cement weight substitution.

  7. Cementation of the solid radioactive waste with polymer-cement solutions using the method of impregnation

    International Nuclear Information System (INIS)

    Gorbunova, O.

    2015-01-01

    Cementation of solid radioactive waste (SRW), i.e. inclusion of solid radioactive waste into cement matrix without cavities - is one of the main technological processes used for conditioning low and intermediate level radioactive waste. At FSUE 'Radon' the industrialized method of impregnation has been developed and since 2003 has been using for cementation of solid radioactive waste. The technology is that the polymer-cement solution, having high penetrating properties, is supplied under pressure through a tube to the bottom of the container in which solid radioactive waste has preliminarily been placed. The polymer-cement solution is evenly moving upwards through the channels between the particles of solid radioactive waste, fills the voids in the bulk volume of the waste and hardens, forming a cement compound, the amount of which is equal to the original volume. The aim of the investigation was a selection of a cement solution suitable for SRW impregnation (including fine particles) without solution depletion and bottom layers stuffing. It has been chosen a polymer: PHMG (polyhexamethylene-guanidine), which is a stabilizing and water-retaining component of the cement solution. The experiments confirm that the polymer increases the permeability of the cement solution by a 2-2.5 factor, the viscosity by a 1.2 factor, the stability of the consistency by a 1.5-1.7 factor, and extends the operating range of the W/C ratio to 0.5-1.1. So it is possible to penetrate a volume of SRW bigger by a 1.5-2.0 factor. It has been proved, that PHMG polymer increases strength and frost-resistance of the final compounds by a 1.8-2.7 factor, and contributes to fast strength development at the beginning of hardening and it decreases Cs-137 leashing rate by a 1.5-2 factor

  8. Potential Use Of Carbide Lime Waste As An Alternative Material To Conventional Hydrated Lime Of Cement-Lime Mortars

    OpenAIRE

    Al Khaja, Waheeb A.

    1992-01-01

    The present study aimed at the possibility of using the carbide lime waste as an alternative material to the conventional lime used for cement-lime mortar. The waste is a by-product obtained in the generation of acetylene from calcium carbide. Physical and chemical properties of the wastes were studied. Two cement-lime-sand mix proportions containing carbide lime waste were compared with the same mix proportions containing conventional lime along with a control mix without lime. Specimens wer...

  9. Study of chemical additives in the cementation of radioactive waste of PWR reactors

    International Nuclear Information System (INIS)

    Vieira, Vanessa Mota; Tello, Cledola Cassia Oliveira de

    2011-01-01

    Cementation is a very useful process to solidify radioactive wastes. Depending on the waste it can be necessary to use of chemical additives (admixtures) to improve the cementation process and its product. Admixtures are materials, other than cement, aggregate and water, that are added either before or during the mixing to alter some properties, such as workability, curing temperature range, and setting time. However there are a large variety of these materials that are frequently changed or taken out of the market. In this changeable scenario it is essential to know the commercially available materials and their characteristics. In this research the effects of chemical admixtures in the solidification process has been studied. For the tests it was prepared a solution simulating the evaporator concentrate waste, cemented by two different formulations, and three chemical admixtures from two manufacturers. The tested admixtures were accelerators, set retarders and super plasticizers. The experiments were organized by a planning factorial 23 to quantify the effects of formulations, of the admixtures, its quantity and manufacturer in properties of the paste and products. The measured parameters were the density, the viscosity and the setting time of the paste, and the product compressive strength. The parameter evaluated in this study was the compressive strength at age of 28 days, is considered essential security issues relating to the handling, transport and storage of cemented waste product. The results showed that the addition of accelerators improved the compressive strength of the cemented products. (author)

  10. Investigating the Influence of Waste Basalt Powder on Selected Properties of Cement Paste and Mortar

    Science.gov (United States)

    Dobiszewska, Magdalena; Beycioğlu, Ahmet

    2017-10-01

    Concrete is the most widely used man-made construction material in civil engineering applications. The consumption of cement and thus concrete, increases day by day along with the growth of urbanization and industrialization and due to new developments in construction technologies, population growing, increasing of living standard. Concrete production consumes much energy and large amounts of natural resources. It causes environmental, energy and economic losses. The most important material in concrete production is cement. Cement industry contributes to production of about 7% of all CO2 generated in the world. Every ton of cement production releases nearly one ton of CO2 to atmosphere. Thus the concrete and cement industry changes the environment appearance and influences it very much. Therefore, it has become very important for construction industry to focus on minimizing the environmental impact, reducing energy consumption and limiting CO2 emission. The need to meet these challenges has spurred an interest in the development of a blended Portland cement in which the amount of clinker is reduced and partially replaced with mineral additives - supplementary cementitious materials (SCMs). Many researchers have studied the possibility of using another mineral powder in mortar and concrete production. The addition of marble dust, basalt powder, granite or limestone powder positively affects some properties of cement mortar and concrete. This paper presents an experimental study on the properties of cement paste and mortar containing basalt powder. The basalt powder is a waste emerged from the preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement, has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance also. The present study shows the results of the research concerning the modification of cement

  11. Modified sulfur cement solidification of low-level wastes

    Energy Technology Data Exchange (ETDEWEB)

    1985-10-01

    This topical report describes the results of an investigation on the solidification of low-level radioactive wastes in modified sulfur cement. The work was performed as part of the Waste Form Evaluation Program, sponsored by the US Department of Energy's Low-Level Waste Management Program. Modified sulfur cement is a thermoplastic material developed by the US Bureau of Mines. Processing of waste and binder was accomplished by means of both a single-screw extruder and a dual-action mixing vessel. Waste types selected for this study included those resulting from advanced volume reduction technologies (dry evaporator concentrate salts and incinerator ash) and those which remain problematic for solidification using contemporary agents (ion exchange resins). Process development studies were conducted to ascertain optimal process control parameters for successful solidification. Maximum waste loadings were determined for each waste type and method of processing. Property evaluation testing was carried out on laboratory scale specimens in order to compare with waste form performance for other potential matrix materials. Waste form property testing included compressive strength, water immersion, thermal cycling and radionuclide leachability. Recommended waste loadings of 40 wt. % sodium sulfate and boric acid salts and 43 wt. % incinerator ash, which are based on processing and performance considerations, are reported. Solidification efficiencies for these waste types represent significant improvements over those of hydraulic cements. Due to poor waste form performance, incorporation of ion exchange resin waste in modified sulfur cement is not recommended.

  12. Modified sulfur cement solidification of low-level wastes

    International Nuclear Information System (INIS)

    1985-10-01

    This topical report describes the results of an investigation on the solidification of low-level radioactive wastes in modified sulfur cement. The work was performed as part of the Waste Form Evaluation Program, sponsored by the US Department of Energy's Low-Level Waste Management Program. Modified sulfur cement is a thermoplastic material developed by the US Bureau of Mines. Processing of waste and binder was accomplished by means of both a single-screw extruder and a dual-action mixing vessel. Waste types selected for this study included those resulting from advanced volume reduction technologies (dry evaporator concentrate salts and incinerator ash) and those which remain problematic for solidification using contemporary agents (ion exchange resins). Process development studies were conducted to ascertain optimal process control parameters for successful solidification. Maximum waste loadings were determined for each waste type and method of processing. Property evaluation testing was carried out on laboratory scale specimens in order to compare with waste form performance for other potential matrix materials. Waste form property testing included compressive strength, water immersion, thermal cycling and radionuclide leachability. Recommended waste loadings of 40 wt. % sodium sulfate and boric acid salts and 43 wt. % incinerator ash, which are based on processing and performance considerations, are reported. Solidification efficiencies for these waste types represent significant improvements over those of hydraulic cements. Due to poor waste form performance, incorporation of ion exchange resin waste in modified sulfur cement is not recommended

  13. Characterization of cement-stabilized Cd wastes

    International Nuclear Information System (INIS)

    Maria Diez, J.; Madrid, J.; Macias, A.

    1996-01-01

    Portland cement affords both physical and chemical immobilization of cadmium. The immobilization has been studied analyzing the pore fluid of cement samples and characterizing the solid pastes by X-ray diffraction. The influence of cadmium on the cement hydration and on its mechanical properties has been also studied by isothermal conduction calorimetry and by the measure of strength and setting development. Finally, the effect of cement carbonation on the immobilization of cadmium has been analyzed

  14. Radioactive Wastes Cementation during Decommissioning Of Salaspils Research Reactor

    International Nuclear Information System (INIS)

    Abramenkova, G.; Klavins, M.; Abramenkovs, A.

    2009-01-01

    This paper deals with information on the radioactive wastes cementation technology for decommissioning of Salaspils Research Reactor (SRR). Dismantled radioactive materials were cemented in concrete containers using tritiated water-cement mortar. The laboratory tests system was developed to meet the waste acceptance criteria for disposal of containers with cemented radioactive wastes in near-surface repository 'Radons'. The viscosity of water-cement mortar, mechanical tests of solidified mortar's samples, change of temperature of the samples during solidification time and leakage of Cs-137 and T-3 radionuclides was studied for different water-cement compositions with different additives. The pH and electro conductivity of the solutions during leakage tests were controlled. It was shown, that water/cement ratio significantly influences on water-cement mortar's viscosity and solidified samples mechanical stability. Increasing of water ratio from 0.45 up to 0.62 decreases water-cement mortar's viscosity from 1100 mPas up to 90 mPas and decreases mechanical stability of water-cement samples from 23 N/mm 2 to the 12 N/mm 2 . The role of additives - fly ash and Penetron admix in reduction of solidification temperature is discussed. It was found, that addition of fly ash to the cement-water mortar can reduce the solidification temperature from 81 deg. C up to 62 deg. C. The optimal interval of water ratio in cement mortar is discussed. Tritium and Cs-137 leakage tests show, that radionuclides release curves has a complicate structure. The possible radionuclides release mechanisms are discussed. Experimental results indicated that addition of fly ash result in facilitation of tritium and cesium leakage in water phase. Further directions of investigations are drafted. (authors)

  15. Feasibility of disposing waste glyphosate neutralization liquor with cement rotary kiln

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Y.; Bao, Y.B.; Cai, X.L.; Chen, C.H. [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Ye, X.C., E-mail: yexuchu@njtech.edu.cn [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China)

    2014-08-15

    Highlights: • The waste neutralization liquor was injected directly into the kiln system. • No obvious effect on the quality of cement clinker. • The disposing method was a zero-discharge process. • The waste liquor can be used as an alternative fuel to reduce the coal consumption. - Abstract: The waste neutralization liquor generated during the glyphosate production using glycine-dimethylphosphit process is a severe pollution problem due to its high salinity and organic components. The cement rotary kiln was proposed as a zero discharge strategy of disposal. In this work, the waste liquor was calcinated and the mineralogical phases of residue were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The mineralogical phases and the strength of cement clinker were characterized to evaluate the influence to the products. The burnability of cement raw meal added with waste liquor and the calorific value of waste liquor were tested to evaluate the influence to the thermal state of the kiln system. The results showed that after the addition of this liquor, the differences of the main phases and the strength of cement clinker were negligible, the burnability of raw meal was improved; and the calorific value of this liquor was 6140 J/g, which made it could be considered as an alternative fuel during the actual production.

  16. Feasibility of disposing waste glyphosate neutralization liquor with cement rotary kiln

    International Nuclear Information System (INIS)

    Bai, Y.; Bao, Y.B.; Cai, X.L.; Chen, C.H.; Ye, X.C.

    2014-01-01

    Highlights: • The waste neutralization liquor was injected directly into the kiln system. • No obvious effect on the quality of cement clinker. • The disposing method was a zero-discharge process. • The waste liquor can be used as an alternative fuel to reduce the coal consumption. - Abstract: The waste neutralization liquor generated during the glyphosate production using glycine-dimethylphosphit process is a severe pollution problem due to its high salinity and organic components. The cement rotary kiln was proposed as a zero discharge strategy of disposal. In this work, the waste liquor was calcinated and the mineralogical phases of residue were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The mineralogical phases and the strength of cement clinker were characterized to evaluate the influence to the products. The burnability of cement raw meal added with waste liquor and the calorific value of waste liquor were tested to evaluate the influence to the thermal state of the kiln system. The results showed that after the addition of this liquor, the differences of the main phases and the strength of cement clinker were negligible, the burnability of raw meal was improved; and the calorific value of this liquor was 6140 J/g, which made it could be considered as an alternative fuel during the actual production

  17. Comparison of the leachability of three TRU cement waste forms

    International Nuclear Information System (INIS)

    Ross, W.A.; Westsik, J.H. Jr.; Roberts, F.P.; Harvey, C.O.

    1982-11-01

    Cement waste forms prepared by three processes, casting, cold pressing, and FUETAP (Formed Under Elevated Temperatures and Pressure) have been compared for their leachability by using the MCC-1 leach test. The results indicate that releases of plutonium are not controlled by the waste form matrix and that there is no significant overall advantage to any of the three cement processes from a leachability viewpoint

  18. Sulfur polymer cement for macroencapsulation of mixed waste debris

    International Nuclear Information System (INIS)

    Mattus, C.H.

    1998-01-01

    In FY 1997, the US DOE Mixed Waste Focus Area (MWFA) sponsored a demonstration of the macroencapsulation of mixed waste debris using sulfur polymer cement (SPC). Two mixed wastes were tested--a D006 waste comprised of sheets of cadmium and a D008/D009 waste comprised of lead pipes and joints contaminated with mercury. The demonstration was successful in rendering these wastes compliant with Land Disposal Restrictions (LDR), thereby eliminating one Mixed Waste Inventory Report (MWIR) waste stream from the national inventory

  19. The thermoelectric generators use for waste heat utilization from cement plant

    Directory of Open Access Journals (Sweden)

    Sztekler Karol

    2017-01-01

    Production often entails the formation of by-product which is waste heat. One of the equipment processing heat into electricity is a thermoelectric generator. Its operation is based on the principle of thermoelectric phenomenon, which is known as a Seebeck phenomenon. The simplicity of thermoelectric phenomena allows its use in various industries, in which the main waste product is in the form of heat with the temperature of several hundred degrees. The study analyses the possibility of the thermoelectric systems use for the waste heat utilization resulting in the cement production at the cement plant. The location and design of the thermoelectric system that could be implemented in cement plant is chosen. The analysis has been prepared in the IPSEpro software.

  20. A literature review of mixed waste components: Sensitivities and effects upon solidification/stabilization in cement-based matrices

    International Nuclear Information System (INIS)

    Mattus, C.H.; Gilliam, T.M.

    1994-03-01

    The US DOE Oak Ridge Field Office has signed a Federal Facility Compliance Agreement (FFCA) regarding Oak Ridge Reservation (ORR) mixed wastes subject to the land disposal restriction (LDR) provisions of the Resource conservation and Recovery Act. The LDR FFCA establishes an aggressive schedule for conducting treatability studies and developing treatment methods for those ORR mixed (radioactive and hazardous) wastes listed in Appendix B to the Agreement. A development, demonstration, testing, and evaluation program has been initiated to provide those efforts necessary to identify treatment methods for all of the wastes that meet Appendix B criteria. The program has assembled project teams to address treatment development needs in a variety of areas, including that of final waste forms (i.e., stabilization/solidification processes). A literature research has been performed, with the objective of determining waste characterization needs to support cement-based waste-form development. The goal was to determine which waste species are problematic in terms of consistent production of an acceptable cement-based waste form and at what concentrations these species become intolerable. The report discusses the following: hydration mechanisms of Portland cement; mechanisms of retardation and acceleration of cement set-factors affecting the durability of waste forms; regulatory limits as they apply to mixed wastes; review of inorganic species that interfere with the development of cement-based waste forms; review of radioactive species that can be immobilized in cement-based waste forms; and review of organic species that may interfere with various waste-form properties

  1. Study of chemical additives in the cementation of radioactive waste of PWR reactors

    International Nuclear Information System (INIS)

    Vieira, Vanessa Mota; Tello, Cledola Cassia Oliveira de

    2012-01-01

    In this research it has been studied the effects of chemical admixtures in the cementation process of radioactive wastes. These additives are used to improve the properties of waste cementation process, both of the paste and of the solidified product. However there are a large variety of these materials that are frequently changed or taken out of the market. Then it is essential to know the commercially available materials and their effects. The tests were carried out with a solution simulating the evaporator concentrate waste coming from PWR nuclear reactors. It was cemented using two formulations, A and B, incorporating higher or lower amount of waste, respectively. It was added chemical admixtures from two manufacturers (S and H), which were: accelerators, set retarders and superplasticizers. The experiments were organized by a factorial design 23. The measured parameters were: the viscosity, the setting time, the paste and product density and the compressive strength. The parameter evaluated in this study was the compressive strength at age of 28 days, is considered essential security issues relating to the handling, transport and storage of cemented waste product. The results showed that the addition of accelerators improved the compressive strength of the cemented products. (author)

  2. Durability of cemented waste in repository and under simulated conditions

    International Nuclear Information System (INIS)

    Dragolici, F.; Nicu, M.; Lungu, L.; Turcanu, C.; Rotarescu, Gh.

    2000-01-01

    The Romanian Radioactive Waste National Repository for low level and intermediate level radioactive waste was built in Baita - Bihor county, in an extinct uranium exploitation. The site is at 840 m above sea level and the host rock is crystalline with a low porosity, a good chemical homogeneity and impermeability, keeping these qualities over a considerable horizontal and vertical spans. To obtain the experimental data necessary for the waste form and package characterization together with the back-filling material behaviour in the repository environment, a medium term research programme (1996 - 2010) was implemented. The purpose of this experimental programme is to obtain a part of the data base necessary for the approach of medium and long term assessment of the safety and performance of Baita - Bihor Repository. The programme will provide: a deeper knowledge of the chemical species and reaction mechanisms, the structure, properties and performances of the final products. For safety reasons the behaviour of waste package, which is a main barrier, must be properly known in terms of long term durability in real repository conditions. Characterization of the behaviour includes many interactions between the waste package itself and the surrounding near field conditions such as mineralogy, hydrogeology and groundwater chemistry. To obtain a more deeper knowledge of the species and physical-chemical reactions participating in the matrix formation, as well as their future behaviour during the disposal period, a thorough XRD study started in 1998. For Romanian Radioactive Waste National Repository (DNDR) Baita - Bihor the following steps are planned for the conditioned waste matrix characterization in simulated and real conditions: - preparation and characterization of normal reference matrices based on different cement formulations; - preparation of reference simulated sludge cemented matrices containing iron hydroxide and iron phosphate; - selection of real and

  3. Formulating a low-alkalinity cement for radioactive waste repositories

    International Nuclear Information System (INIS)

    Coumes, C. Cau Dit; Courtois, S.; Leclercq, S.; Bourbon, X.

    2004-01-01

    A multi-annual research program has been launched in January 2003 by CEA, EDF and ANDRA in order to formulate and characterize low-alkalinity and low-heat cements which would be compatible with an underground waste repository environment. Four types of bindings have been investigated: binary blends of Portland cement and silica fume or metakaolin, as well as ternary blends of Portland cement, fly ash and silica fume or metakaolin. Promising results have been obtained with a mixture comprising 37.5% Portland cement, 32.5% silica fume, and 30% fly ash: pH of water in equilibrium with fully hydrated cement is below 11. Moreover, silica fume compensates for the low reactivity of fly ash, while fly ash allows to reduce water demand, heat release, and dimensional variations of cement pastes and mortars. (authors)

  4. Formulating a low-alkalinity cement for radioactive waste repositories

    Energy Technology Data Exchange (ETDEWEB)

    Coumes, C. Cau Dit; Courtois, S.; Leclercq, S.; Bourbon, X

    2004-07-01

    A multi-annual research program has been launched in January 2003 by CEA, EDF and ANDRA in order to formulate and characterize low-alkalinity and low-heat cements which would be compatible with an underground waste repository environment. Four types of bindings have been investigated: binary blends of Portland cement and silica fume or metakaolin, as well as ternary blends of Portland cement, fly ash and silica fume or metakaolin. Promising results have been obtained with a mixture comprising 37.5% Portland cement, 32.5% silica fume, and 30% fly ash: pH of water in equilibrium with fully hydrated cement is below 11. Moreover, silica fume compensates for the low reactivity of fly ash, while fly ash allows to reduce water demand, heat release, and dimensional variations of cement pastes and mortars. (authors)

  5. Immobilization of radioactive waste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, D.; McCulloch, C.E.; Angus, M.J.

    1985-06-01

    The kinetics of reaction between cement and clinoptilolite are elucidated and rate equations containing temperature dependent constants derived for this reaction. Variations in clinoptilolite particle size and their consequences to reactivity are assessed. The presence of pozzolanic agents more reactive than clinoptilolite provides sacrificial agents which are partially effective in lowering the clinoptilolite reactivity. Blast furnace slag-cements have been evaluated and the background literature summarized. Experimental studies of the pore fluid in matured slag-cements show that they provide significantly more immobilization for Cs than Portland cement. The distribution of Sr in cemented waste forms has been examined, and it is shown that most of the chemical immobilization potential in the short term is likely to be associated with the aluminate phases. The chemical and structural nature of these are described. Carbonation studies on real cements are summarized. (author)

  6. Studies on cement matrix materials used at the Radioactive Waste Treatment Plant for radwaste conditioning

    International Nuclear Information System (INIS)

    Dragolici, Felicia; Lungu, Laura; Nicu, Mihaela; Rotarescu, Gheorghe; Turcanu, Corneliu

    2003-01-01

    The research activities performed by Department of Radioactive Waste Management is focused on the treatment of LLAW products obtained by chemical precipitation and on the conditioning of these products by cementation. The individual mechanisms implied in the chemical precipitation processes are directly dependent on the precipitate properties and structure, which in turn are connected with the initial system composition and the precipitation procedure, i.e. reagent concentration, rate and orders of chemical addition, mixing rate and time and ageing conditions. In case of conditioning by cementation, the chemical nature and proportion of the sludges or concentrates affect both the hydrolysis of the initial cement components and the reactions of metastable hydration constituents, as well as the mechanical strength and chemical resistance of the hardened cemented matrix.Generally, the study of the precipitation products and their behaviour during cementation and the long-term disposal is extremely difficult because of the system complexity (phase composition and structure) and the lack of the non-destructive analytical methods. The experience accumulated by the countries who advanced nuclear programmes in military and socio-economic fields and which produced important volumes of radioactive wastes, leads us to study some of mineral additives to be used in the conditioning and disposal technology. Is well known that some mineral additives can diminish the leaching rate of the radionuclides in the disposal environment.The studies have the purpose to obtain the most propitious mixture of cement-bentonite and cement-volcanic tuff, which have the mechanical properties similar to the cement paste used for the conditioning of radioactive waste.Taking into account the characteristics of these mineral binders, namely a very good plasticity and capacity of adsorption, which lead at the decrease of porosity, the mixture is planned to be used in the future, at the Radioactive

  7. Acoustic monitoring techniques for corrosion degradation in cemented waste canisters

    International Nuclear Information System (INIS)

    Naish, C.C.; Buttle, D.; Wallace-Sims, R.; O'Brien, T.M.

    1991-01-01

    This report describes work carried out to investigate acoustic emission as a monitor of corrosion and degradation of wasteforms where the waste is potentially reactive metal. Electronic monitoring equipment has been designed, built and tested to allow long-term monitoring of a number of waste packages simultaneously. Acoustic monitoring experiments were made on a range of 1 litre cemented Magnox and aluminium samples cast into canisters comparing the acoustic events with hydrogen gas evolution rates and electrochemical corrosion rates. The attenuation of the acoustic signals by the cement grout under a range of conditions has been studied to determine the volume of wasteform that can be satisfactorily monitored by one transducer. The final phase of the programme monitored the acoustic events from full size (200 litre) cemented, inactive, simulated aluminium swarf wastepackages prepared at the AEA waste cementation plant at Winfrith. (Author)

  8. Investigations on cement/polymer Waste packages containing intermediate level waste and organic exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    ELsourougy, M R; Zaki, A A; Aly, H F [Atomic energy authority, hot laboratory center, Cairo, (Egypt); Khalil, M Y [Nuclear engineering department, Alexandria university. Alexandria, (Egypt)

    1995-10-01

    Polymers can be added to cements to improve its nuclear waste immobilization properties. This trend in cementation processes is attracting attention and requiring through investigations. In this work, polymers of different kinds were added to ordinary portland cement for the purpose of solidifying intermediate level liquid wastes and organic ion exchange resins. Epoxy polymer such as Kemapoxy-150 reduced the leaching rate of cesium compared to cement alone. Latex to cement ratio less than 4% caused an increase in leaching rate of cesium. When cesium was absorbed to an organic resin its leachability was improved. 5 figs., 4 tabs.

  9. Investigations on cement/polymer Waste packages containing intermediate level waste and organic exchange resins

    International Nuclear Information System (INIS)

    ELsourougy, M.R.; Zaki, A.A.; Aly, H.F.; Khalil, M.Y.

    1995-01-01

    Polymers can be added to cements to improve its nuclear waste immobilization properties. This trend in cementation processes is attracting attention and requiring through investigations. In this work, polymers of different kinds were added to ordinary portland cement for the purpose of solidifying intermediate level liquid wastes and organic ion exchange resins. Epoxy polymer such as Kemapoxy-150 reduced the leaching rate of cesium compared to cement alone. Latex to cement ratio less than 4% caused an increase in leaching rate of cesium. When cesium was absorbed to an organic resin its leachability was improved. 5 figs., 4 tabs

  10. Device for cementing radioactive of toxic waste into barrels

    International Nuclear Information System (INIS)

    Hempelmann, W.; Waldenmeier, G.; Mathis, P.; Mathis, B.; Mathis, F.

    1987-01-01

    The plant consists of conventional means, such as through mixers and dosing and transport spirals, which are accommodated in a glovebox. The inactive additives cement and sand and the active materials evaporation concentrates and sludges are mixed by them, and are then filled into a waste barrel which is empty or already filled with solid waste. Liquid radioactive wastes are used to concrete over the solid waste. (DG) [de

  11. Structural and microstructural aspects of asbestos-cement waste vitrification

    Science.gov (United States)

    Iwaszko, Józef; Zawada, Anna; Przerada, Iwona; Lubas, Małgorzata

    2018-04-01

    The main goal of the work was to evaluate the vitrification process of asbestos-cement waste (ACW). A mixture of 50 wt% ACW and 50 wt% glass cullet was melted in an electric furnace at 1400 °C for 90 min and then cast into a steel mold. The vitrified product was subjected to annealing. Optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to evaluate the effects of the vitrification. The chemical constitution of the material before and after the vitrification process was also analyzed. It was found that the vitrified product has an amorphous structure in which the components of asbestos-cement waste are incorporated. MIR spectroscopy showed that the absorption bands of chrysotile completely disappeared after the vitrification process. The results of the spectroscopic studies were confirmed by X-ray studies - no diffraction reflections from the chrysotile crystallographic planes were observed. As a result of the treatment, the fibrous asbestos construction, the main cause of its pathogenic properties, completely disappeared. The vitrified material was characterized by higher resistance to ion leaching in an aquatic environment than ACW and a smaller volume of nearly 72% in relation to the apparent volume of the substrates. The research has confirmed the high effectiveness of vitrification in neutralizing hazardous waste containing asbestos and the FT-IR spectroscopy was found to be useful to identify asbestos varieties and visualizing changes caused by the vitrification process. The work also presents the current situation regarding the utilization of asbestos-containing products.

  12. The use of mexican cements in the low and medium radioactive wastes confinement

    International Nuclear Information System (INIS)

    Badillo A, V.E.; Almazan T, M.G.; Alonso V, G.; Palacios H, J.C.

    2008-01-01

    Inside the relative mark to the radioactive waste confinement, minerals of great fixation capacity like clays, apatites and diverse oxides are studied as matrixes, components and/or additives of the active barriers that separate the barrier geologic and the nuclear wastes. In this case, the cements intervene in those different stages of the waste management, since its are used for the immobilization of radioactive waste in the container, for the production of containers as well as filler of the spaces among the containers of the vaults, and also as engineering barrier and construction material in the civil work. For the above mentioned, it is particularly useful to characterize the Portland cements with at least 97% of clinker, since they are most recommended for this type of applications. Presently investigation work is carried out a preliminary chemical characterization, based on the mineralogical composition, of the Portland Mexican cement. Results are shown by the X-ray Diffraction technique when immobilizing a rich solution in sulfates to 5%, using two Portland commercial cements APASCO and TOLTECA, without observing the significant appearance of new phases. The cements besides incorporating the chemical species in the breast of the matrix, are also present as barriers of civil engineering in the facilities located only some meters deep for the storage of radioactive waste of low and intermediate level, for that the study of the radionuclides fixation, in the cements is of supreme importance to evaluate the safety of a nuclear repository with the help of cements; the retention of the iodine-131 in a limited interval of pH in the commercial APASCO and TOLTECA it was studied, being observed a scarce retention of this homologous of fission products, what indicates the necessity to use additives to improve the retention properties of the Mexican commercial cements for some radionuclides. (Author)

  13. Solid recovered fuels in the cement industry with special respect to hazardous waste.

    Science.gov (United States)

    Thomanetz, Erwin

    2012-04-01

    Cements with good technical properties have been produced in Europe since the nineteenth century and are now worldwide standardized high-quality mass products with enormous production numbers. The basic component for cement is the so-called clinker which is produced mainly from raw meal (limestone plus clay plus sands) in a rotary kiln with preheater and progressively with integrated calciner, at temperatures up to 1450 °C. This process requires large amounts of fossil fuels and is CO₂-intensive. But most CO₂ is released by lime decomposition during the burning process. In the 1980s the use of alternative fuels began--firstly in the form of used oil and waste tyres and then increasingly by pre-conditioned materials from commercial waste and from high calorific industrial waste (i.e. solid recovered fuel (SRF))--as well as organic hazardous waste materials such as solvents, pre-conditioned with sawdust. Therefore the cement industry is more and more a competitor in the waste-to-energy market--be it for municipal waste or for hazardous waste, especially concerning waste incineration, but also for other co-incineration plants. There are still no binding EU rules identifying which types of SRF or hazardous waste could be incinerated in cement kilns, but there are some well-made country-specific 'positive lists', for example in Switzerland and Austria. Thus, for proper planning in the cement industry as well as in the waste management field, waste disposal routes should be considered properly, in order to avoid surplus capacities on one side and shortage on the other.

  14. Characterization of different types of ceramic waste and its incorporation to the cement paste

    International Nuclear Information System (INIS)

    Cunha, G.A.; Evangelista, A.C.J.; Almeida, V.C. de

    2009-01-01

    The porcelain tike is a product resulting from the technological development of ceramic plating industry. Its large acceptation by the consumer market is probably linked with certain properties, such as low porosity, high mechanical resistance, facility in maintenance, besides being a material of modern and versatile characteristics. The aim of this work was characterizing the different ceramic wastes (enameled and porcelain tike) and evaluating its influence on the mechanical behavior in cement pastes. The wastes were characterized through the determination of its chemical composition, size particle distribution and X-ray diffraction. Cement pastes + wastes were prepared in 25% and 50% proportions and glue time determination, water absorption and resistance to compression assays were taken. The results indicate that although the wastes don't show any variation in the elementary chemical composition, changes in the cement paste behavior related to the values of resistance to compression were observed. (author)

  15. Proposal of Solidification/Stabilisation Process of Chosen Hazardous Waste by Cementation

    OpenAIRE

    Bozena Dohnalkova

    2015-01-01

    This paper presents a part of the project solving which is dedicated to the identification of the hazardous waste with the most critical production within the Czech Republic with the aim to study and find the optimal composition of the cement matrix that will ensure maximum content disposal of chosen hazardous waste. In the first stage of project solving – which represents this paper – a specific hazardous waste was chosen, its properties were identified and suitable soli...

  16. Compatibility of cement with low and medium level wastes generated at nuclear power plants

    International Nuclear Information System (INIS)

    De Angelis, G.

    1987-01-01

    The incorporation of low- and medium level wastes in cement can give rise to serious problems due to the interaction between radwastes and cement components. Some troubles can occur during the first stages of the cementation process while deleterious phenomena come into evidence in the medium and long term. With the aim to improve the quality of the final waste forms a pretreatment of the waste streams is often necessary, as well as the addition of special agents to the cement matrix. The prediction of the long-term behaviour of the final products is of main importance in this research field. To this purpose some accelerated tests have been proposed, but much effort should be further devoted to the comprehension of the waste/matrix interaction. In this paper the principal waste streams are reviewed together with the possible remedies which seem to be more suitable for their cementation. Thus the qpportunity of separatly handling and solidifying different types of waste is once more supported

  17. The transformation of waste Bakelite to replace natural fine aggregate in cement mortar

    Directory of Open Access Journals (Sweden)

    Nopagon Usahanunth

    2017-06-01

    Full Text Available Bakelite material has been used to produce the various components for cars and consumer goods industry in Thailand. The growth of Bakelite consumption increases Bakelite waste. Bakelite waste is prohibited from disposing of direct landfilling and open burning because of the improper disposal and emission reasons. A large amount of this waste needs the large safe space of warehouse area for keeping which becomes a waste management problem. Size reduction by milling machine is helpful for waste handling and storing, however, the post-milling waste Bakelite plastic utilization shall be studied to maintain the waste storing capacity. There are some studies of the milling machine used for waste plastic size reduction. However, the particular study of milling machine application for waste size reduction and its milling waste utilization is still insufficient in Thailand. The purpose of this research is the use of waste Bakelite aggregate milling machine for Bakelite waste size reduction and use of the post-milling waste Bakelite as a fine aggregate to replace natural sand material in cement mortar. The waste Bakelite fine aggregate (WBFA was mixed in cement mortar mixture with the proportion 0% 20% 40% 60% 80% and 100% by volume for cement mortar sample preparation. The mortar sample was tested for compressive strength follow ASTM standard. The compressive test result of mortar samples will be compared between conventional mortar (0% WBFA and waste Bakelite mortar (WBM as well as comparing with the mortar standard. From an analysis of the sample test data found that the WBFA content in cement mortar mixture can predict the strength of WBM. The compressive strength of WBM at 28 days age with the fraction of WBFA is not exceeded 11.03%, and 23.08% respectively can be met the mortar standard according to the equation. The utilization of WBM to develop mortar non-structural mortar product can be usable from a technical point of view.

  18. Heat of hydration measurements on cemented radioactive wastes. Part 1: cement-water pastes

    International Nuclear Information System (INIS)

    Lee, D.J.

    1983-12-01

    This report describes the hydration of cement pastes in terms of chemical and kinetic models. A calorimetric technique was used to measure the heat of hydration to develop these models. The effects of temperature, water/cement ratio and cement replacements, ground granulated blast furnace slag (BFS) and pulverised fuel ash (PFA) on the hydration of ordinary Portland cement (OPC) is reported. The incorporation of BFS or PFA has a marked effect on the hydration reaction. The effect of temperature is also important but changing the water/cement ratio has little effect. Results from cement pastes containing only water and cement yield total heats of reaction of 400, 200 and 100 kJ/kg for OPC, BFS and PFA respectively. Using the results from the models which have been developed, the effect of major salts present in radioactive waste streams can be assessed. Values of the total heat of reaction, the time to complete 50 percent reaction, and the energy of activation, can be compared for different waste systems. (U.K.)

  19. Characterization of surrogate radioactive cemented waste: a laboratory study

    International Nuclear Information System (INIS)

    Fiset, J.F.; Lastra, R.; Bilodeau, A.; Bouzoubaa

    2011-01-01

    Portland cement is commonly used to stabilize intermediate and low level of radioactive wastes. The stabilization/solidification process needs to be well understood as waste constituents can retard or activate cement hydration. The objectives of this project were to prepare surrogate radioactive cemented waste (SRCW), develop a comminution strategy for SRCW, determine its chemical characteristics, and develop processes for long term storage. This paper emphasizes on the characterization of surrogate radioactive cemented waste. The SRCW produced showed a high degree of heterogeneity mainly due to the method used to add the solution to the host cement. Heavy metals such as uranium and mercury were not distributed uniformly in the pail. Mineralogical characterization (SEM, EDS) showed that uranium is located around the rims of hydrated cement particles. In the SRCW, uranium occurs possibly in the form of a hydrated calcium uranate.The SEM-EDS results also suggest that mercury occurs mainly in the form of HgO although some metallic mercury may be also present as a result of partial decomposition of the HgO. (author)

  20. The characterization of cement waste form for final disposal of decommissioning concrete wastes

    International Nuclear Information System (INIS)

    Lee, Yoon-ji; Lee, Ki-Won; Min, Byung-Youn; Hwang, Doo-Seong; Moon, Jei-Kwon

    2015-01-01

    Highlights: • Decommissioning concrete waste recycling and disposal. • Compressive strength of cement waste form. • Characteristic of thermal resistance and leaching of cement waste form. - Abstract: In Korea, the decontamination and decommissioning of KRR-1, 2 at KAERI have been under way. The decommissioning of the KRR-2 was finished completely by 2011, whereas the decommissioning of KRR-1 is currently underway. A large quantity of slightly contaminated concrete waste has been generated from the decommissioning projects. The concrete wastes, 83ea of 200 L drums, and 41ea of 4 m 3 containers, were generated in the decommissioning projects. The conditioning of concrete waste is needed for final disposal. Concrete waste is conditioned as follows: mortar using coarse and fine aggregates is filled with a void space after concrete rubble pre-placement into 200 L drums. Thus, this research developed an optimizing mixing ratio of concrete waste, water, and cement, and evaluated the characteristics of a cement waste form to meet the requirements specified in the disposal site specific waste acceptance criteria. The results obtained from a compressive strength test, leaching test, and thermal cycling test of cement waste forms conclude that the concrete waste, water, and cement have been suggested as an optimized mixing ratio of 75:15:10. In addition, the compressive strength of the cement waste form was satisfied, including a fine powder up to a maximum of 40 wt% in concrete debris waste of about 75%. According to the scale-up test, the mixing ratio of concrete waste, water, and cement is 75:10:15, which meets the satisfied compressive strength because of an increase in the particle size in the waste

  1. High-level radioactive waste incorporation into (special) cements

    International Nuclear Information System (INIS)

    Roy, D.M.; Gouda, G.R.

    1978-01-01

    A feasibility study has demonstrated that very strong, durable, relatively impermeable cylinders may be prepared by hot pressing combinations of cements with simulated radioactive waste solids. While the properties have not been studied exhaustively, the results suggest an optional method for immobilization and isolation of radioactive waste. Samples prepared with calcium aluminate cements appeared to have properties superior to those with Portland cements. Four simulated radioactive waste compositions having high rare-earth oxide contents, and some containing a large excess of NaNO 3 , were studied. Modest temperatures [423 to 673 K (150 to 400 0 C)] were used for hot pressing at pressures from 178 to 345 MPa. Dense strong very low porosity specimens resulted when mixtures containing from 10 to 50% waste were hot pressed, incorporating also a small percentage of water. In addition, high-strength cement cylinders were prepared with the waste solid (approximately 20 wt% waste) in a separate core and were very resistant to leaching by water near its boiling point. With this configuration, even the NaNO 3 -containing wastes were resistant to leaching by water

  2. Utilization of waste glass in ECO-cement: Strength properties and microstructural observations

    International Nuclear Information System (INIS)

    Sobolev, Konstantin; Tuerker, Pelin; Soboleva, Svetlana; Iscioglu, Gunsel

    2007-01-01

    Waste glass creates a serious environmental problem, mainly because of the inconsistency of the waste glass streams. The use of waste glass as a finely ground mineral additive (FGMA) in cement is a promising direction for recycling. Based on the method of mechano-chemical activation, a new group of ECO-cements was developed. In ECO-cement, relatively large amounts (up to 70%) of portland cement clinker can be replaced with waste glass. This report examines the effect of waste glass on the microstructure and strength of ECO-cement based materials. Scanning electron microscopy (SEM) investigations were used to observe the changes in the cement hydrates and interface between the cement matrix and waste glass particles. According to the research results, the developed ECO-cement with 50% of waste glass possessed compressive strength properties at a level similar to normal portland cement

  3. Evaluation of national cements for the conditioning of radioactive wastes

    International Nuclear Information System (INIS)

    Mallaupoma, M.; Soriano, A.; Rodriguez, G.; Cruz, W.

    1996-01-01

    The preliminary research studies carried out to implement the liquid radioactive waste conditioning by cementation are described. First of all, different kind of commercial cements in Peru are analyzed. In the first step, the analysis were made without using the radioactive material. The analyzed parameters were density, porosity, setting time and mechanical strength of a cement type called 'Atlas'. Samples of two geometries were used. One of them was a cylindrical sample (48mm diameter and 48mm height) and the another one was a prismatic sample (40x40x160mm). The results of the different kind of analysis are presented in this paper. (authors). 2 refs., 3 tabs

  4. Employing 3R Techniques in Managing Cement Industry Waste

    Directory of Open Access Journals (Sweden)

    Lamyaa Mohammed Dawood

    2018-01-01

    Full Text Available Waste management conserves human health, ownership, environment, and keeps valuable natural resources. Lean-green waste of an organization’s operations can be decreased through implementation 3R (Reduce, Reuse, and Recycling techniques by reduction of manufacturing system wastes. This research aims to integrate lean-green waste of the manufacturing system throughout employing 3R techniques and weighted properties method in order to manage waste. Al-Kufa cement plant is employed as a case study. Results are generated using Edraw Max Version 7 and Excel. Overall results show reduce technique of lean-green waste management has major contribution of 55 % and recycling technique has minor contribution 18 %. Defects waste has major integration of lean-green waste, while air emissions waste has minor integration of lean-green waste.

  5. Immobilization of Radioactive Waste in Different Fly Ash Zeolite Cement Blends

    International Nuclear Information System (INIS)

    Sami, N.M.

    2013-01-01

    The problem of radioactive waste management has been raised from the beginning use of nuclear energy for different purposes. The rad waste streams produced were sufficient to cause dangerous effects to man and its environment. The ordinary portland cement is the material more extensively used in the technologies of solidification and immobilization of the toxic wastes, low and medium level radioactive wastes. The production of portland cement is one of the most energy-intensive and polluting. The use of high energy in the production causes high emission due to the nature and processes of raw materials. The cement industry is responsible for 7% of the total CO 2 emission. Thus, the cement industry has a crucial role in the global warming. The formation of alite (Ca 3 SiO 5 ), which is the main component of the Portland cement clinker, produces a greater amount of CO 2 emission than the formation of belite (Ca 2 SiO 4 ). The proportion of alite to belite is about 3 in ordinary Portland clinker. Therefore, by decreasing this proportion less CO 2 would be emitted. Furthermore, if industrial byproducts such as fly ash from thermal power station or from incineration of municipal solid wastes have the potential to reduce CO 2 used as raw materials and alternative hydrothermal calcination routes are employed for belite clinker production, CO 2 emission can be strongly reduced or even totally avoided. The availability of fly ash will help in reducing the CO 2 emissions and will also help in resolving, to a great extent, the fly ash disposal problem. This thesis is based on focusing on the possibility of using fly ash as raw materials to prepare low cost innovation matrices for immobilization of radioactive wastes by synthesizing new kind of cement of low consuming energy. The synthesis process is based on the hydrothermal-calcination route of the fly ash without extra additions.

  6. Durability of incinerator ash waste encapsulated in modified sulfur cement

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Pietrzak, R.; Colombo, P.

    1991-01-01

    Waste form stability under anticipated disposal conditions is an important consideration for ensuring continued isolation of contaminants from the accessible environment. Modified sulfur cement is a relatively new material and has only recently been applied as a binder for encapsulation of mixed wastes. Little data are available concerning its long-term durability. Therefore, a series of property evaluation tests for both binder and waste-binder combinations have been conducted to examine potential waste form performance under storage and disposal conditions. These tests include compressive strength, biodegradation, radiation stability, water immersion, thermal cycling, and leaching. Waste form compressive strength increased with ash waste loadings to 30.5 MPa at a maximum incinerator ash loading of 43 wt %. Biodegradation testing resulted in no visible microbial growth of either bacteria or fungi. Initial radiation stability testing did not reveal statistically significant deterioration in structural integrity. Results of 90 day water immersion tests were dependent on the type of ash tested. There were no statistically significant changes in compressive strength detected after completion of thermal cycle testing. Radionuclides from ash waste encapsulated in modified sulfur cement leached between 5 and 8 orders of magnitude slower than the leach index criterion established by the Nuclear Regulatory Commission (NRC) for low-level radioactive waste. Modified sulfur cement waste forms containing up to 43 wt % incinerator fly ash passed EPA Toxicity Characteristic Leaching Procedure (TCLP) criteria for lead and cadmium leachability. 11 refs., 2 figs., 5 tabs

  7. Effect of curing time on the fraction of Cs137 from cement-waste matrix

    International Nuclear Information System (INIS)

    Plecas, I.; Pavlovic, R.; Pavlovic, S.

    2003-01-01

    To assess the safety of disposal of radioactive waste material in cement, curing conditions and time of leaching radionuclides 137 Cs have been studied. Leaching tests in cement-waste matrix, were carried out in accordance with a method recommended by IAEA. Curing conditions and curing time prior to commencing the leaching test are critically important in leach studies since the extent of hydration of the cement materials determines how much hydration product develops and whether it is available to block the pore network, thereby reducing leaching. Results presented in this paper are examples of results obtained in a 10-year concrete testing project which will influence the design of the engineer trenches system for future central Yugoslav radioactive waste storing center. (orig.)

  8. Evolution of cement based materials in a repository for radioactive waste and their chemical barrier function

    International Nuclear Information System (INIS)

    Kienzler, Bernhard; Metz, Volker; Schlieker, Martina; Bohnert, Elke

    2015-01-01

    The use of cementitious materials in nuclear waste management is quite widespread. It covers the solidification of low/intermediate-level liquid as well as solid wastes (e.g. laboratory wastes) and serves as shielding. For both high-level and intermediate-low level activity repositories, cement/concrete likewise plays an important role. It is used as construction material for underground and surface disposals, but more importantly it serves as barrier or sealing material. For the requirements of waste conditioning, special cement mixtures have been developed. These include special mixtures for the solidification of evaporator concentrates, borate binding additives and for spilling solid wastes. In recent years, low-pH cements were strongly discussed especially for repository applications, e.g. (Celine CAU DIT COUMES 2008; Garcia-Sineriz, et al. 2008). Examples for relevant systems are Calcium Silicate Cements (ordinary Portland cement (OPC) based) or Calcium Aluminates Cements (CAC). Low-pH pore solutions are achieved by reduction of the portlandite content by partial substitution of OPC by mineral admixtures with high silica content. The blends follow the pozzolanic reaction consuming Ca(OH) 2 . Potential admixtures are silica fume (SF) and fly ashes (FA). In these mixtures, super plasticizers are required, consisting of polycarboxilate or naphthalene formaldehyde as well as various accelerating admixtures (Garcia-Sineriz, et al. 2008). The pH regime of concrete/cement materials may stabilize radionuclides in solution. Newly formed alteration products retain or release radionuclides. An important degradation product of celluloses in cement is iso-saccharin acid. According to Glaus 2004 (Glaus and van Loon 2004), it reacts with radionuclides forming dissolved complexes. Apart from potentially impacting radionuclide solubility limitations, concrete additives, radionuclides or other strong complexants compete for surface sites for sorbing onto cement phases. In

  9. Mathematical modelling of transport phenomena in radioactive waste-cement-bentonite matrix

    International Nuclear Information System (INIS)

    Plecas, Ilija; Dimovic, Slavko

    2010-01-01

    Document available in extended abstract form only. The leaching rate of 137 Cs from spent mix bead (anion and cation) exchange resins in a cement-bentonite matrix has been studied. Transport phenomena involved in the leaching of a radioactive material from a cement-bentonite matrix are investigated using three methods based on theoretical equations. These are: the diffusion equation for a plane source an equation for diffusion coupled to a first-order equation and an empirical method employing a polynomial equation. The results presented in this paper are from a 25-year mortar and concrete testing project that will influence the design choices for radioactive waste packaging for a future Serbian radioactive waste disposal center. Radioactive waste is waste material containing radioactive chemical elements which does not have a practical purpose. It is often the product of a nuclear process, such as nuclear fission. Waste can also be generated from the processing of fuel for nuclear reactors or nuclear weapons. The main objective in managing and disposing of radioactive (or other) waste is to protect people and the environment. This means isolating or diluting the waste so that the rate or concentration of any radionuclides returned to the biosphere is harmless. Storage as the placement of waste in a nuclear facility where isolation, environmental protection and human control are provided with the intent that the waste will be retrieved at a later time. Disposal as the emplacement of waste in an approved, specified facility (e.g. near surface or geological repository) without the intention of retrieval. The processing of radioactive wastes may be done for economic reasons (e.g. to reduce the volume for storage or disposal, or to recover a 'resource' from the waste), or safety reasons (e.g. converting the waste to a more 'stable' form, such as one that will contain the radionuclide inventory for a long time). Typically processing involves reducing

  10. Westinghouse integrated cementation facility. Smart process automation minimizing secondary waste

    International Nuclear Information System (INIS)

    Fehrmann, H.; Jacobs, T.; Aign, J.

    2015-01-01

    The Westinghouse Cementation Facility described in this paper is an example for a typical standardized turnkey project in the area of waste management. The facility is able to handle NPP waste such as evaporator concentrates, spent resins and filter cartridges. The facility scope covers all equipment required for a fully integrated system including all required auxiliary equipment for hydraulic, pneumatic and electric control system. The control system is based on actual PLC technology and the process is highly automated. The equipment is designed to be remotely operated, under radiation exposure conditions. 4 cementation facilities have been built for new CPR-1000 nuclear power stations in China

  11. Immobilization of radioactive waste through cementation using Cuban zeolitic rock as additive

    International Nuclear Information System (INIS)

    Chales Suarez, G.; Castillo Gomez, R.

    1997-01-01

    The cementation of both simulated and real low level aqueous wastes using Cuban zeolite as additive is described. Mechanical characteristics and leach testing of the cemented waste forms has been studied. The results obtained have shown that the presence of zeolite in the cemented waste for reduces considerably the leach rates of Cs and Co and moreover, mechanical characteristics (set time and compressive strength) are better when compared with direct cementation of aqueous wastes. (author). 13 refs, 8 tabs

  12. Cementation of biodegraded radioactive oils and organic waste

    International Nuclear Information System (INIS)

    Gorbunova, O.; Safonov, A.; Tregubova, V.; German, K.

    2015-01-01

    The possibility of the microbiological pre-treatment of the oil-containing organic liquid radioactive waste (LRW) before solidification in the cement matrix has been studied. It is experimentally proved that the oil containing cement compounds during long-term storage are subject to microbiological degradation due to the reaction of biogenic organic acids with the minerals of the cement matrix. We recommend to biodegrade the LRW components before their solidification, which reduces the volume of LRW and prevent the destruction of the inorganic cement matrix during the long term storage. The biodegradation of the oil containing LRW is possible by using the radioresistant microflora which oxidize the organic components of the oil to carbon dioxide and water. Simultaneously there is the bio-sorption of the radionuclides by bacteria and emulsification of oil in cement slurry due to biogenic surface-active substances of glycolipid nature. It was experimentally established that after 7 days of biodegradation of oil-containing liquid radioactive waste the volume of LRW is reduced by the factor from 2 to 10 due to the biodegradation of the organic phase to the non-radioactive gases (CH 4 , H 2 O, CO 2 , N 2 ), which are excluded from the volume of the liquid radioactive waste. At the same time, the microorganisms are able to extract from the LRW up to 80-90% of alpha-radionuclides, up to 50% of 90 Sr, up to 20% of 137 Cs due to sorption processes at the cellular structures. The radioactive biomass is subject to dehydration and solidification in the matrix. The report presents the following experimental data: type of bacterial flora, the parameters of biodegradation, the cementing parameters, the properties of the final cement compound with oil-containing liquid radioactive waste

  13. Environmental interactions of cement-based products

    NARCIS (Netherlands)

    Florea, M.V.A.; Schmidt, W.; Msinjili, N.S.

    2016-01-01

    The environmental interactions of concrete and other cement-based products encompasses both the influence of such materials on their environment, as well as the effects of the environment on the materials in time. There are a number of ways in which the environmental impact of concrete can be

  14. Sodium Sulphate Effect on Cement Produced with Building Stone Waste

    Directory of Open Access Journals (Sweden)

    Emre Sancak

    2015-01-01

    Full Text Available In this study, the blended cements produced by using the building stone waste were exposed to sulphate solution and the cement properties were examined. Prepared mortar specimens were cured under water for 28 days and then they were exposed to three different proportions of sodium sulphate solution for 125 days. Performances of cements were determined by means of compressive strength and tensile strength tests. The broken parts of some mortar bars were examined with scanning electron microscope (SEM. Besides, they were left under moist atmosphere and their length change was measured and continuously monitored for period of 125 days. In blended cements, solely cements obtained by replacing 10–20% of diatomites gave similar strength values with ordinary Portland cement (CEM I 42.5R at the ages of 7, 28, and 56 days. In all mortar specimens that included either waste andesite (AP or marble powder (MP showed best performance against very severe effective sodium sulphate solutions (13500 mg/L.

  15. 40 CFR 63.1220 - What are the replacement standards for hazardous waste burning cement kilns?

    Science.gov (United States)

    2010-07-01

    ... hazardous waste burning cement kilns? 63.1220 Section 63.1220 Protection of Environment ENVIRONMENTAL... Waste Combustors Replacement Emissions Standards and Operating Limits for Incinerators, Cement Kilns... burning cement kilns? (a) Emission and hazardous waste feed limits for existing sources. You must not...

  16. Measurement and control of cement set times in waste solidification

    International Nuclear Information System (INIS)

    Stone, J.A.; d'Entremont, P.D.

    1976-09-01

    Fixation of radioactive waste in concrete was investigated on laboratory scale. Some cement formulations containing simulated or actual sludges from the Savannah River Plant had set times that would be too short for reliable handling in plant equipment. Set times could be controlled by use of excess water, but the concrete forms produced had inferior strength. A commercial organic retarder was found to be effective for increasing set times of cement-sludge formulations. However, the dosage of retarder required to control set times of high-alumina cement formulations was 1.0 to 1.5 wt percent of dry solids, which is 5 to 10 times the normal dosage for Portland cements. Data were obtained to predict the optimum content of retarder and water

  17. The characterization of cement waste form for final disposal of decommissioned concrete waste

    International Nuclear Information System (INIS)

    Lee, K.W.; Lee, Y.J.; Hwang, D.S.; Moon, J.K.

    2015-01-01

    Since the decommissioning of nuclear plants and facilities, large quantities of slightly contaminated concrete waste have been generated. In Korea, the decontamination and decommissioning of the KRR-1, 2 at the KAERI have been under way. In addition, 83 drums of 200 l, and 41 containers of 4 m 3 of concrete waste were generated. Conditioning of concrete waste is needed for final disposal. Concrete waste is conditioned as follows: mortar using coarse and fine aggregates is filled into a void space after concrete rubble pre-placement into 200 l drums. Thus, this research developed an optimizing mixing ratio of concrete waste, water, and cement, and evaluated the characteristics of a cement waste form to meet the requirements specified in the disposal site specific waste acceptance criteria. The results obtained from compressive strength test, leaching test, and thermal cycling test of cement waste forms conclude that the concrete waste, water, and cement have been suggested to have 75:15:10 as the optimized mixing ratio. In addition, the compressive strength of cement waste form was satisfied, including fine powder up to a maximum 40 wt% in concrete debris waste of about 75%. (authors)

  18. Processes and Equipment for the Cementation of Radioactive Waste

    International Nuclear Information System (INIS)

    Schaefer, S.; Studenski, J.

    2012-01-01

    In this article a short selection of different cement mixer types provided by NUKEM Technologies is given. The variety stems on one hand from historical development, but more especially from specific customer demands to meet their local and technical requirements. The Slant Batch Mixer is successfully installed in several Waste Treatment Centers (WTC). NUKEM Technologies set up these mixers with necessary auxiliary systems to facilitate all the cementation tasks of a WTC. By the slant design of the mixer a homogeneous intermixing and a rapid and comprehensive emptying is achieved. The High Shear Mixer is a batch mixer producing a thixotropic, fast flowing colloidal cement slurry. NUKEM Technologies uses this cement slurry to bubble-free/ empty space-free grouting of pre-packed solid waste items in container. The High Throughput Continuous Mixer is a continuously operating screw mixer that provides a high throughput. One or more dry components are continuously fed to the mixer where liquid waste or water is added. The High Performance In-Drum Mixer is a combination of planetary mixer with double helical mixer. NUKEM Technologies recently has developed a new High Capacity Mixer (HCM) based on a well proven conventional concrete mixer. The HCM is the successor of the slant mixer and will expend NUKEM Technologies' portfolio of cementation units. (A.C.)

  19. Using of borosilicate glass waste as a cement additive

    International Nuclear Information System (INIS)

    Han, Weiwei; Sun, Tao; Li, Xinping; Sun, Mian; Lu, Yani

    2016-01-01

    Highlights: • Borosilicate glass waste used as cement additive can improves its radiation shielding. • When content is 14.8%, the linear attenuation coefficient is 0.2457 cm"−"1 after 28 d. • From 0 to 22.2%, linear attenuation coefficient firstly increase and then decrease. - Abstract: Borosilicate glass waste is investigated as a cement additive in this paper to improve the properties of cement and concrete, such as setting time, compressive strength and radiation shielding. The results demonstrate that borosilicate glass is an effective additive, which not only improves the radiation shielding properties of cement paste, but also shows the irradiation effect on the mechanical and optical properties: borosilicate glass can increase the compressive strength and at the same time it makes a minor impact on the setting time and main mineralogical compositions of hydrated cement mixtures; and when the natural river sand in the mortar is replaced by borosilicate glass sand (in amounts from 0% to 22.2%), the compressive strength and the linear attenuation coefficient firstly increase and then decrease. When the glass waste content is 14.8%, the compressive strength is 43.2 MPa after 28 d and the linear attenuation coefficient is 0.2457 cm"−"1 after 28 d, which is beneficial for the preparation of radiation shielding concrete with high performances.

  20. Using of borosilicate glass waste as a cement additive

    Energy Technology Data Exchange (ETDEWEB)

    Han, Weiwei [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, Hubei 430070 (China); School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Sun, Tao, E-mail: sunt@whut.edu.cn [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Li, Xinping [Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Sun, Mian [School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, Hubei 430070 (China); Lu, Yani [Urban Construction Institute, Hubei Engineering University, Xiaogan, Hubei 432000 (China)

    2016-08-15

    Highlights: • Borosilicate glass waste used as cement additive can improves its radiation shielding. • When content is 14.8%, the linear attenuation coefficient is 0.2457 cm{sup −1} after 28 d. • From 0 to 22.2%, linear attenuation coefficient firstly increase and then decrease. - Abstract: Borosilicate glass waste is investigated as a cement additive in this paper to improve the properties of cement and concrete, such as setting time, compressive strength and radiation shielding. The results demonstrate that borosilicate glass is an effective additive, which not only improves the radiation shielding properties of cement paste, but also shows the irradiation effect on the mechanical and optical properties: borosilicate glass can increase the compressive strength and at the same time it makes a minor impact on the setting time and main mineralogical compositions of hydrated cement mixtures; and when the natural river sand in the mortar is replaced by borosilicate glass sand (in amounts from 0% to 22.2%), the compressive strength and the linear attenuation coefficient firstly increase and then decrease. When the glass waste content is 14.8%, the compressive strength is 43.2 MPa after 28 d and the linear attenuation coefficient is 0.2457 cm{sup −1} after 28 d, which is beneficial for the preparation of radiation shielding concrete with high performances.

  1. Long-term interactions of full-scale cemented waste simulates with salt brines

    Energy Technology Data Exchange (ETDEWEB)

    Kienzler, B.; Borkel, C.; Metz, V.; Schlieker, M.

    2016-07-01

    Since 1967 radioactive wastes have been disposed of in the Asse II salt mine in Northern Germany. A significant part of these wastes originated from the pilot reprocessing plant WAK in Karlsruhe and consisted of cemented NaNO{sub 3} solutions bearing fission products, actinides, as well as process chemicals. With respect to the long-term behavior of these wastes, the licensing authorities requested leaching experiments with full scale samples in relevant salt solutions which were performed since 1979. The experiments aimed at demonstrating the transferability of results obtained with laboratory samples to real waste forms and at the investigation of the effects of the industrial cementation process on the properties of the waste forms. This research program lasted until 2013. The corroding salt solutions were sampled several times and after termination of the experiments, the solid materials were analyzed by various methods. The results presented in this report cover the evolution of the solutions and the chemical and mineralogical characterization of the solids including radionuclides and waste components, and the paragenesis of solid phases (corrosion products). The outcome is compared to the results of model calculations. For safety analysis, conclusions are drawn on radionuclide retention, evolution of the geochemical environment, evolution of the density of solutions, and effects of temperature and porosity of the cement waste simulates on cesium mobilization.

  2. Long-term interactions of full-scale cemented waste simulates with salt brines

    International Nuclear Information System (INIS)

    Kienzler, B.; Borkel, C.; Metz, V.; Schlieker, M.

    2016-01-01

    Since 1967 radioactive wastes have been disposed of in the Asse II salt mine in Northern Germany. A significant part of these wastes originated from the pilot reprocessing plant WAK in Karlsruhe and consisted of cemented NaNO 3 solutions bearing fission products, actinides, as well as process chemicals. With respect to the long-term behavior of these wastes, the licensing authorities requested leaching experiments with full scale samples in relevant salt solutions which were performed since 1979. The experiments aimed at demonstrating the transferability of results obtained with laboratory samples to real waste forms and at the investigation of the effects of the industrial cementation process on the properties of the waste forms. This research program lasted until 2013. The corroding salt solutions were sampled several times and after termination of the experiments, the solid materials were analyzed by various methods. The results presented in this report cover the evolution of the solutions and the chemical and mineralogical characterization of the solids including radionuclides and waste components, and the paragenesis of solid phases (corrosion products). The outcome is compared to the results of model calculations. For safety analysis, conclusions are drawn on radionuclide retention, evolution of the geochemical environment, evolution of the density of solutions, and effects of temperature and porosity of the cement waste simulates on cesium mobilization.

  3. The effects of large scale processing on caesium leaching from cemented simulant sodium nitrate waste

    International Nuclear Information System (INIS)

    Lee, D.J.; Brown, D.J.

    1982-01-01

    The effects of large scale processing on the properties of cemented simulant sodium nitrate waste have been investigated. Leach tests have been performed on full-size drums, cores and laboratory samples of cement formulations containing Ordinary Portland Cement (OPC), Sulphate Resisting Portland Cement (SRPC) and a blended cement (90% ground granulated blast furnace slag/10% OPC). In addition, development of the cement hydration exotherms with time and the temperature distribution in 220 dm 3 samples have been followed. (author)

  4. Immobilisation of shredded soft waste in cement monolith

    International Nuclear Information System (INIS)

    Brown, D.J.; Dalton, M.J.; Smith, D.L.

    1983-04-01

    A grouting process for the immobilisation of shredded contaminated laboratory waste in a cement monolith is being developed at the Atomic Energy Establishment Winfrith. The objective is to produce a 'monolithic' type package which is acceptable both for sea and land disposal. The work carried out on this project in the period April 1982 - March 1983 is summarised in this report. (author)

  5. Adaptation of magnesian cements to underground storage of nuclear wastes

    International Nuclear Information System (INIS)

    Dufournet, F.

    1987-01-01

    The aim of this thesis is the experimental study of magnesium oxychloride cements as filling materials for underground granitic cavities containing high level radioactive wastes. After a bibliographic study, mechanical properties are examined before and after setting, in function of the ratio MgO/MgCl 2 . Then behavior with water is investigated: swelling, cracking and leaching [fr

  6. Modern methods for evaluating the workability of cement used as a binder for the stabilization and solidification of toxic wastes

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, Giorgio [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1997-10-01

    The workability of cement pastes has a great influence on the final properties of the solidified products, like mechanical strength, stability density and durability. This is quite relevant in the field of stabilization / solidification of toxic and hazardous wastes. Hence considerable importance attaches to having reliable control over the fresh concrete properties, especially its early stiffening behaviour. This paper discussers measuring methods of the stiffening of two different types of cement pastes, prepared with different water / cement ratios, and examines the possible consequences of the early stiffening of cement pastes on their set times and bleeding.

  7. Effect of Cement Replacement with Carbide Waste on the Strength of Stabilized Clay Subgrade

    Directory of Open Access Journals (Sweden)

    Muntohar A.S.

    2016-03-01

    Full Text Available Cement is commonly used for soil stabilization and many other ground improvement techniques. Cement is believed to be very good to improve the compressive and split-tensile strength of clay subgrades. In some application cement could be partly or fully replaced with carbide waste. This research is to study the effectiveness of the cement replacement and to find the maximum carbide waste content to be allowed for a clay subgrade. The quantities of cement replaced with the carbide waste were 30, 50, 70, 90, and 100% by its mass. The results show that replacing the cement with carbide waste decreased both the compressive and split tensile strength. Replacing cement content with carbide waste reduced its ability for stabilization. The carbide waste content should be less than 70% of the cement to provide a sufficient stabilizing effect on a clay subgrade.

  8. Immobilization of strontium and cesium in intermediate-level liquid wastes by solidification in cements

    International Nuclear Information System (INIS)

    Rudolph, G.; Koester, R.

    1979-01-01

    An accelerated leach test at elevated temperature has been developed which gives intercomparable results within one day. It is very useful for product quality control at large throughputs. Using this test, it has been shown that cesium leachabilities from cement products containing a simulated waste typical of fuel reprocessing plants can be reduced by addition of a bentonite. Addition of barium silicate hydrate retards strontium leaching in these cements. Leach rates in tap water and in salt brine are lower than in distilled water and sodium chloride solution

  9. Enhancement of cemented waste forms by supercritical CO2 carbonation of standard portland cements

    International Nuclear Information System (INIS)

    Rubin, J.B.; Carey, J.; Taylor, C.M.V.

    1997-01-01

    We are conducting experiments on an innovative transformation concept, using a traditional immobilization technique, that may significantly reduce the volume of hazardous or radioactive waste requiring transport and long-term storage. The standard practice for the stabilization of radioactive salts and residues is to mix them with cements, which may include additives to enhance immobilization. Many of these wastes do not qualify for underground disposition, however, because they do not meet disposal requirements for free liquids, decay heat, head-space gas analysis, and/or leachability. The treatment method alters the bulk properties of a cemented waste form by greatly accelerating the natural cement-aging reactions, producing a chemically stable form having reduced free liquids, as well as reduced porosity, permeability and pH. These structural and chemical changes should allow for greater actinide loading, as well as the reduced mobility of the anions, cations, and radionuclides in aboveground and underground repositories. Simultaneously, the treatment process removes a majority of the hydrogenous material from the cement. The treatment method allows for on-line process monitoring of leachates and can be transported into the field. We will describe the general features of supercritical fluids, as well as the application of these fluids to the treatment of solid and semi-solid waste forms. some of the issues concerning the economic feasibility of industrial scale-up will be addressed, with particular attention to the engineering requirements for the establishment of on-site processing facilities. Finally, the initial results of physical property measurements made on portland cements before and after supercritical fluid processing will be presented

  10. The incorporation of low and medium level radioactive wastes (solids and liquids) in cement

    International Nuclear Information System (INIS)

    Palmer, J.D.; Smith, D.L.

    1985-07-01

    Experimentation has shown that high temperatures generated during the setting of ordinary Portland cement/simulant waste mixes can be significantly reduced by the use of a blend of ground granulated blast furnace slag and ordinary Portland cement. Trials on simulated waste showed that blended cement gave improved stability and a reduction in leach rates, and confirmed that the cement-based process can be used for the immobilisation of most types of low and medium level waste. (U.K.)

  11. Cement-Polymer Composite Containers for Radioactive Wastes Disposal

    International Nuclear Information System (INIS)

    Ghattas, N.K.; Eskander, S.B.; Bayoumi, T.A.; Saleh, H.M.

    2009-01-01

    Improving cement-composite containers using polymer as organic additives was studied extensively. Both unsaturated styrenated polyester (SPE) and polymethyl methacrylate (PMMA) were used to fill the pores in cement containers that used for disposal of radioactive wastes. Two different techniques were adopted for the addition of organic polymers based on their viscosity. The low density PMMA was added using impregnation technique. On the other hand high density SPE was mixed with cement paste as a premix process. Predetermined weight of dried borate radioactive powder waste simulate was introduced into the Cement-polymer composite (CPC) container and then closed before subjecting it to leaching characterization. The effect of the organic polymers on the hydration of cement matrix and on the properties of the obtained CPC container has been studied using X-ray diffraction, IR-analysis, thermal effects and weight loss. Porosity, pore parameters and rate of release were also determined. The results obtained showed that for the candidate CPC container positive effect of polymer dominates and an improvement in the retardation rate of PMMA release radionuclides was observed

  12. Method of processing radioactive liquid wastes by solidification with cement

    International Nuclear Information System (INIS)

    Yasumura, Keijiro; Matsuura, Hiroyuki.

    1975-01-01

    Object: To subject radioactive liquid wastes to a cement solidification treatment after heating and drying it by a thin film scrape-off drier to render it into the form of power, and then molding it into pellets for the treatment. Structure: Radioactive liquid wastes discharged from a nuclear power plant or nuclear reactor are supplied through a storage tank into a thin film scrape-off drier. In the drier, the radioactive liquid wastes are heated to separate the liquid, and the residue is taken out as dry powder from the scrape-off apparatus. The powder obtained in this way is molded into pellets of a desired form. These pellets are then packed in a drum can or similar container, into which cement paste is then poured for solidification. (Moriyama, K.)

  13. Global CO2 emissions from cement production

    Science.gov (United States)

    Andrew, Robbie M.

    2018-01-01

    The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4 Gt CO2, 66 % of which have occurred since 1990. Emissions in 2015 were 30 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831455.

  14. Cementation of secondary wastes generated from carbonisation of spent organic ion exchange resins from nuclear power plants

    International Nuclear Information System (INIS)

    Sathi Sasidharan, N.; Deshingkar, D.S.; Wattal, P.K.

    2004-07-01

    The spent IX resins containing radioactive fission and activation products from power reactors are highly active solid wastes generated during operations of nuclear reactors. Process for carbonization of IX resins to achieve weight and volume reduction has been optimized on 50 dm 3 /batch pilot test rig. The process generates carbonaceous residue, organic liquid condensates (predominantly styrene) and aqueous alkaline scrubber solutions as secondary wastes. The report discusses laboratory tests on leaching of 137 Cs from cement matrix incorporating carbonaceous residues and extrapolation of results to 200 liter matrix block. The cumulative fraction of 137 Cs leached from 200 liter cement matrix was estimated to be 0.0021 in 200 days and 0.0418 over a period of 30 years. Incorporation of organic liquid condensates into cement matrix has been tried out successfully. Thus two types of secondary wastes generated during carbonization of spent IX resins can be immobilized in cement matrix. (author)

  15. Cement waste form qualification report: WVDP [West Valley Demonstration Project] PUREX decontaminated supernatant

    International Nuclear Information System (INIS)

    McVay, C.W.; Stimmel, J.R.; Marchetti, S.

    1988-08-01

    This report provides a summary of work performed to develop a cement-based, low-level waste formulation suitable for the solidification of decontaminated high-level waste liquid produced as a by-product of PUREX spent fuel reprocessing. The resultant waste form is suitable for interim storage and is intended for ultimate disposal as low-level Class C waste; it also meets the stability requirements of the NRC Branch Technical Position on Waste Form Qualification, May 1983 and the requirements of 10 CFR 61. A recipe was developed utilizing only Portland Type I cement based on an inorganic salts simulant of the PUREX supernatant. The qualified recipe was tested full scale in the production facility and was observed to produce a product with entrained air, low density, and lower-than-expected compressive strength. Further laboratory scale testing with actual decontaminated supernatant revealed that set retarders were present in the supernatant, precluding setting of the product and allowing the production of ''bleed water.'' Calcium nitrate and sodium silicate were added to overcome the set retarding effect and produced a final product with improved performance when compared to the original formulation. This report describes the qualification process and qualification test results for the final product formulation. 7 refs., 38 figs., 21 tabs

  16. Effect of silica fume on reaction products of uranium (VI) with portland cement

    International Nuclear Information System (INIS)

    Tan Hongbin; Shaanxi Univ. of Technology, Hanzhong; Li Yuxiang

    2005-01-01

    Simulation of radioactive waste of U(VI) by uranyl nitrate and the effects of different additive quantities (12%, 20%, 30%, 35%, 40%) of silica fume on the products of U(VI) with Portland cement were studied at a hydrothermal condition of 180 degree C for a duration of one week. The X-ray powder diffraction examination results showed that the calcium uranate would be transformed into uranophane when the cement contained 30% silica fume. (authors)

  17. Cementation of Radioactive Waste from a PWR with Calcium Sulfoaluminate Cement

    International Nuclear Information System (INIS)

    Li, J.

    2013-01-01

    Spent radioactive ion-exchange resin (SIER) and evaporation concentrates are radioactive wastes that are produced at by pressurized water reactor (PWR) nuclear power stations. Borate, which is used as a retardent for cement, is also present as a moderator in a PWR, therefore, borate will be present in both ion-exchange resins and evaporation concentrates. In this study the use of Calcium sulfoaluminate cements (SAC) as encapsulation medium for these waste streams was investigated. The study involved the manufacturing of different cement test samples with different amounts of SAC cement, waste resins (50% water content) and admixtures. In order to reduce hydration heat during 200 L solidification experiments, different admixtures were investigated. Initial results based on compressive strength tests and hydration temperature studies, indicated that zeolite was the best admixture for the current waste form. Experiments indicated that the addition of resin material into the current cement matrix reduces the hydration heat during curing Experimental results indicated that a combination of SAC (35 wt. %), zeolite (7 wt. %) mix with 42 wt. % resins (50% water content) and 16 wt. % of water forms a optimum cured monolith with low hydration heat. The microstructures of hydrated OPC, SAC and SAC with zeolite addition were studied using a Scanning Electron Microscopy (SEM). SEM results indicated that the SAC matrices consist of a needle type structure that changed gradually into a flake type structure with the addition of zeolite. Additionally, the presence of zeolite material inside the SAC matrix reduced the leaching rates of radionuclides significantly. In a final 200 L grouting test, measured results indicated a hydration temperature below 90oC withno thermal cracks after solidified. The influence of radiation on the compressive strength and possible gas generation (due to radiolysis) on cement waste forms containing different concentrations ion exchange resin was

  18. Accelerated ageing of blended cements for use in radioactive waste disposal

    International Nuclear Information System (INIS)

    Quillin, K.; Duerden, S.L.; Majumdar, A.J.

    1993-01-01

    An accelerated experimental technique has been developed to study the long term hydration of blended cements that may be used in radioactive waste disposal. This technique has been used to investigate the hydration reactions of Ordinary Portland Cement (OPC) blended with blast furnace slag (ggbs) or pulverised fuel ash (pfa). The effects of high sulphate-bearing and high carbonate-bearing ground waters on the compounds formed on hydration was also investigated. Solid/solution compositional data has been collected during the course of the hydration process and this can be used in the validation of models for the properties of cements. Thomsonite, afwillite, a tobermorite-like phase and thaumasite have been found in addition to the expected cement hydration products and need to be considered in modelling studies of cement hydration. The pH of ground waters reacted with OPC/pfa blends on hydration at 90 o C fell below 8. This is lower than the value required to inhibit the corrosion of steel canisters in a repository. The pH in ground waters reacted with OPC and OPC/ggbs mixes remained above 11, although if the ground waters reacted with OPC/ggbs blends were periodically replaced the pH eventually fell below 10. The experimental procedure could be adapted to test the specific cement and ground water compositions relevant to the design of an underground repository over a range of experimental conditions. (author)

  19. Vitrified medical wastes bottom ash in cement clinkerization. Microstructural, hydration and leaching characteristics.

    Science.gov (United States)

    Papamarkou, S; Christopoulos, D; Tsakiridis, P E; Bartzas, G; Tsakalakis, K

    2018-04-19

    The present investigation focuses on the utilization of medical wastes incineration bottom ash (MBA), vitrified with soda lime recycled glass (SLRG), as an alternative raw material in cement clinkerization. Bottom ash is recovered from the bottom of the medical wastes incineration chamber, after being cooled down through quenching. It corresponds to 10-15 wt% of the initial medical wastes weight and since it has been classified in the category of hazardous wastes, its safe management has become a major environmental concern worldwide. MBA glasses of various syntheses were initially obtained during the MBA vitrification simultaneously with various amounts of silica scrap (20, 25 and 30 wt% correspondingly). The produced MBA glasses were in turn used for the production of Portland cement clinker, after sintering at 1400 °C, thus substituting traditional raw materials. Both evaluation of vitrification and sintering products was carried out by chemical and mineralogical analyses along with microstructure examination. The final cements were prepared by clinkers co-grinding in a laboratory ball mill with appropriate amounts of gypsum (≈5.0 wt%) and the evaluation of their quality was carried out by determining setting times, standard consistency, expansibility and compressive strength at 2, 7, 28 and 90 days. Finally, the leaching behaviour of the vitrified MBA and hydrated cements, together with the corresponding of the "as received" MBA, was further examined using the standard leaching tests of the Toxicity Characteristic Leaching Procedure (TCLP) and the EN 12457-2. According to the obtained results, the quality of the produced cement clinkers was not affected by the addition of the vitrified MBA in the raw meal, with the trace elements detected in all leachates measured well below the corresponding regulatory limits. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Modified sulphur cement: A low porosity encapsulation material for low, medium and alpha waste

    International Nuclear Information System (INIS)

    Dalen, A. van; Rijpkema, J.E.

    1989-01-01

    Modified sulphur cement, available under the trade name Chement 2000, is a thermoplastic candidate material for the matrix of low, intermediate and alpha radioactive waste. The main source of sulphur is the desulphurization of fossil fuels. In view of the future increase of this product a modified compound of sulphur has been developed at the US Bureau of Mines. Modified sulphur cement as matrix material has properties in common with Portland or blast furnace cement and bitumen. The mechanical strength is comparable to hydraulic cement products. The process to incorporate waste materials is identical to bitumization. The leachability and the resistance to attack by chemicals is nearly the same as for bituminized products. This study showed also that the radiation resistance is high without radiolytic gas production and without change in dimensions (swelling). The rigidity of the matrix is a disadvantage when internal pressures are built up. The thermal conductivity and the heat of combustion of sulphur is low resulting in slow damage to the waste form under fire conditions, even when the temperature of self ignition in air is 220 0 C. The low leachability, the very slow effective diffusion of H 2 O and HTO, and the low permeability is due to the small pore diameters in the modified sulphur matrix. The loading capacity of modified sulphur cement depends on grain size and distribution and is for ungraded ashes, precipitates, dried sludges, etc., in the order of 40-50% of weight. The price of Chement 2000 per tonne is equal to those of blown bitumen

  1. Performance of cement solidification with barium for high activity liquid waste including sulphate

    International Nuclear Information System (INIS)

    Waki, Toshikazu; Yamada, Motoyuki; Horikawa, Yoshihiko; Kaneko, Masaaki; Saso, Michitaka; Haruguchi, Yoshiko; Yamashita, Yu; Sakai, Hitoshi

    2009-01-01

    The target liquid waste to be solidified is generated from PWR primary loop spent resin treatment with sulphate acid, so, its main constituent is sodium sulphate and the activity of this liquid is relatively high. Waste form of this liquid waste is considered to be a candidate for the subsurface disposal. The disposed waste including sulphate is anticipated to rise a concentration of sulphate ion in the ground water around the disposal facility and it may cause degradation of materials such as cement and bentonite layer and comprise the disposal facility. There could be two approaches to avoid this problem, the strong design of the disposal facility and the minimization of sulphaste ion migration from the solidified waste. In this study, the latter approach was examined. In order to keep the low concentration of sulphate ion in the ground water, it is effective to make barium sulphate by adding barium compound into the liquid waste in solidification. However, adding equivalent amount of barium compound with sulphate ion causes difficulty of mixing, because production of barium sulphate causes high viscosity. In this study, mixing condition after and before adding cement into the liquid waste was estimated. The mixing condition was set with consideration to keep anion concentration low in the ground water and of mixing easily enough in practical operation. Long term leaching behavior of the simulated solidified waste was also analyzed by PHREEQC. And the concentration of the constitution affected to the disposal facility was estimated be low enough in the ground water. (author)

  2. Cement Types, Composition, Uses and Advantages of Nanocement, Environmental Impact on Cement Production, and Possible Solutions

    Directory of Open Access Journals (Sweden)

    S. P. Dunuweera

    2018-01-01

    Full Text Available We first discuss cement production and special nomenclature used by cement industrialists in expressing the composition of their cement products. We reveal different types of cement products, their compositions, properties, and typical uses. Wherever possible, we tend to give reasons as to why a particular cement type is more suitable for a given purpose than other types. Cement manufacturing processes are associated with emissions of large quantities of greenhouse gases and environmental pollutants. We give below quantitative and qualitative analyses of environmental impact of cement manufacturing. Controlling pollution is a mandatory legal and social requirement pertinent to any industry. As cement industry is one of the biggest CO2 emitters, it is appropriate to discuss different ways and means of CO2 capture, which will be done next. Finally, we give an account of production of nanocement and advantages associated with nanocement. Nanofillers such as nanotitania, nanosilica, and nanoalumina can be produced in large industrial scale via top-down approach of reducing size of naturally available bulk raw materials to those in the nanorange of 1 nm–100 nm. We mention the preparation of nanotitania and nanosilica from Sri Lankan mineral sands and quartz deposits, respectively, for the use as additives in cement products to improve performance and reduce the amount and cost of cement production and consequent environmental impacts. As of now, mineral sands and other treasures of minerals are exported without much value addition. Simple chemical modifications or physical treatments would add enormous value to these natural materials. Sri Lanka is gifted with highly pure quartz and graphite from which silica and graphite nanoparticles, respectively, can be prepared by simple size reduction processes. These can be used as additives in cements. Separation of constituents of mineral sands is already an ongoing process.

  3. Recycle of fired phosphogypsum waste product as a cement replacement and its role on the hydration and strength development of pastes

    International Nuclear Information System (INIS)

    Tantawi, S.H.

    2005-01-01

    The effect of Partially up to fully substituted of treated phosphogypsum x(PG) for natural gypsum on the physico- mechanical as well as kinetic of hydration of ordinary Portland cement has been discussed . The results show that by increasing PG % the water to cement ratio decreased while the initial and final setting times increased So PG acts as a retarder and water reducer . The retardation effect may be attributed to formation of ettringite layer which formed on the surface of C3A of cement pastes . The chemically combined water, free lime content and bulk density increased with curing time and with PG content for all cement pastes up to 90 days due to increasing of the rate of hydration. The compressive strength increased by increasing of PG % due to formation of anhydrite , changes in major oxides content and reduction of impurities . X-Ray Diffraction, SEM and DTA of some samples have been studied

  4. Use of MRF residue as alternative fuel in cement production.

    Science.gov (United States)

    Fyffe, John R; Breckel, Alex C; Townsend, Aaron K; Webber, Michael E

    2016-01-01

    Single-stream recycling has helped divert millions of metric tons of waste from landfills in the U.S., where recycling rates for municipal solid waste are currently over 30%. However, material recovery facilities (MRFs) that sort the municipal recycled streams do not recover 100% of the incoming material. Consequently, they landfill between 5% and 15% of total processed material as residue. This residue is primarily composed of high-energy-content non-recycled plastics and fiber. One possible end-of-life solution for these energy-dense materials is to process the residue into Solid Recovered Fuel (SRF) that can be used as an alternative energy resource capable of replacing or supplementing fuel resources such as coal, natural gas, petroleum coke, or biomass in many industrial and power production processes. This report addresses the energetic and environmental benefits and trade-offs of converting non-recycled post-consumer plastics and fiber derived from MRF residue streams into SRF for use in a cement kiln. An experimental test burn of 118 Mg of SRF in the precalciner portion of the cement kiln was conducted. The SRF was a blend of 60% MRF residue and 40% post-industrial waste products producing an estimated 60% plastic and 40% fibrous material mixture. The SRF was fed into the kiln at 0.9 Mg/h for 24h and then 1.8 Mg/h for the following 48 h. The emissions data recorded in the experimental test burn were used to perform the life-cycle analysis portion of this study. The analysis included the following steps: transportation, landfill, processing and fuel combustion at the cement kiln. The energy use and emissions at each step is tracked for the two cases: (1) The Reference Case, where MRF residue is disposed of in a landfill and the cement kiln uses coal as its fuel source, and (2) The SRF Case, in which MRF residue is processed into SRF and used to offset some portion of coal use at the cement kiln. The experimental test burn and accompanying analysis indicate

  5. Wide-scale utilization of MSWI fly ashes in cement production and its impact on average heavy metal contents in cements: The case of Austria.

    Science.gov (United States)

    Lederer, Jakob; Trinkel, Verena; Fellner, Johann

    2017-02-01

    A number of studies present the utilization of fly ashes from municipal solid waste incineration (MSWI) in cement production as a recycling alternative to landfilling. While there is a lot of research on the impact of MSWI fly ashes utilization in cement production on the quality of concrete or the leaching of heavy metals, only a few studies have determined the resulting heavy metal content in cements caused by this MSWI fly ashes utilization. Making use of the case of Austria, this study (1) determines the total content of selected heavy metals in cements currently produced in the country, (2) designs a scenario and calculates the resulting heavy metal contents in cements assuming that all MSWI fly ashes from Austrian grate incinerators were used as secondary raw materials for Portland cement clinker production and (3) evaluates the legal recyclability of demolished concretes produced from MSWI fly ash amended cements based on their total heavy metal contents. To do so, data from literature and statistics are combined in a material flow analysis model to calculate the average total contents of heavy metals in cements and in the resulting concretes according to the above scenario. The resulting heavy metal contents are then compared (i) to their respective limit values for cements as defined in a new technical guideline in Austria (BMLFUW, 2016), and (ii) to their respective limit values for recycling materials from demolished concrete. Results show that MSWI fly ashes utilization increases the raw material input in cement production by only +0.9%, but the total contents of Cd by +310%, and Hg, Pb, and Zn by +70% to +170%. However these and other heavy metal contents are still below their respective limit values for Austrian cements. The same legal conformity counts for recycling material derived from concretes produced from the MSWI fly ash cements. However, if the MSWI fly ash ratio in all raw materials used for cement production were increased from 0.9% to 22

  6. Cement Waste Matrix Evaluation and Modelling of the Long Term Stability of Cementitious Waste Matrices

    International Nuclear Information System (INIS)

    Martensson, P.; Cronstrand, P.

    2013-01-01

    Cement based materials are often used as a solidification matrix for wet radioactive waste from nuclear power plants such as ion exchange resins, sludge and evaporator concentrates. The mechanical and chemical properties of the cement-waste matrix are affected by the type and the concentration of the waste. For this reason the recipe used in the solidification process has to be carefully adjusted to respond to the variations of the waste. At the Ringhals Nuclear Power Plant (RNPP) an evaporator was to be taken into operation during the mid 2005. As a result of this process an evaporator concentrate containing boric acid was expected. The aims of the present study were to develop a recipe for the solidification of artificial evaporator concentrates, (AEC), containing H 3 BO 3 and measure the compressive strength of the waste/cement matrix over a period of 4 years. The confirmation of the previously reported retarding properties of H 3 BO 3 and the studies of AEC without H 3 BO 3 were also included as a part of this work. Finally, thermodynamic calculations were used as a tool in order to predict the evolution of the mineralogy and integrity for the different cement-waste specimens over very long periods of time, i.e. up to about 100 000 years. The most important finding was that when an optimized waste/cement matrix recipe was used the compressive strength increased during the entire 4 year period and no signs of degradation were noticed. It was also found that the long-term performance of the waste matrices is to a large extent site-specific. In general, the composition of the infiltrating water is more influential than the waste matrices, both on the degradation of the waste matrices itself as well as on the engineered barriers. (author)

  7. Analysis of cement solidified product and ash samples and preparation of a reference material

    International Nuclear Information System (INIS)

    Ishimori, Ken-ichiro; Haraga, Tomoko; Shimada, Asako; Kameo, Yutaka; Takahashi, Kuniaki

    2010-08-01

    Simple and rapid analytical methods for radionuclides in low-level radioactive waste have been developed by the present authors. The methods were applied to simulated solidified products and actual metal wastes to confirm their usefulness. The results were summarized as analytical guide lines. In the present work, cement solidified product and ash waste were analyzed followed by the analytical guide lines and subjects were picked up and solved for the application of the analytical guide lines to these wastes. Pulverization and homogenization method for ash waste was improved to prevent a contamination since the radioactivity concentrations of the ash samples were relatively high. Pre-treatment method was altered for the cement solidified product and ash samples taking account for their high concentration of Ca. Newly, an analytical method was also developed to measure 129 I with a dynamic reaction cell inductively coupled plasma mass spectrometer. In the analytical test based on the improved guide lines, gamma-ray emitting nuclides, 60 Co and 137 Cs, were measured to estimate the radioactivity of the other alpha and beta-ray emitting nuclides. The radionuclides assumed detectable, 3 H, 14 C, 36 Cl, 63 Ni, 90 Sr, and alpha-ray emitting nuclides, were analyzed with the improved analytical guide lines and their applicability for cement solidified product and ash samples were confirmed. Additionally a cement solidified product sample was evaluated in terms of the homogeneity and the radioactivity concentrations in order to prepare a reference material for radiochemical analysis. (author)

  8. Practical Model of Cement Based Grout Mix Design, for Use into Low Level Radiation Waste Management

    Directory of Open Access Journals (Sweden)

    Radu Lidia

    2015-12-01

    Full Text Available The cement based grouts, as functional performance composite materials, are widely used for both immobilisation and encapsulation as well as for stabilization in the field of inorganic waste management. Also, to ensure that low level radioactive waste (LLW are contained for storage and ultimate disposal, they are encapsulated or immobilized in monolithic waste forms, with cement –based grouts.

  9. Characterization of cement minerals, cements and their reaction products at the atomic and nano scale

    DEFF Research Database (Denmark)

    Skibsted, Jørgen; Hall, Christopher

    2008-01-01

    Recent advances and highlights in characterization methods are reviewed for cement minerals, cements and their reaction products. The emphasis is on X-ray and neutron diffraction, and on nuclear magnetic resonance methods, although X-ray absorption and Raman spectroscopies are discussed briefly...

  10. Characterization of cement minerals, cements and their reaction products at the atomic and nano scale

    International Nuclear Information System (INIS)

    Skibsted, Jorgen; Hall, Christopher

    2008-01-01

    Recent advances and highlights in characterization methods are reviewed for cement minerals, cements and their reaction products. The emphasis is on X-ray and neutron diffraction, and on nuclear magnetic resonance methods, although X-ray absorption and Raman spectroscopies are discussed briefly

  11. Mineralogy and microstructure of two Mexican Portland cements for the confinement of radioactive waste

    International Nuclear Information System (INIS)

    Galicia A, E.; Badillo A, V. E.; Ramirez S, J. R.; Nava E, N.

    2014-10-01

    The cementitious materials are involved in the different stages of radioactive waste management because they are used for the waste immobilization in the container, as well as filling in the spaces between containers vaults and also as engineering barrier and construction material in civil construction site. Therefore, is necessary to have a study of commercial cement available nationwide involving solid timely analysis in order to identify which phases are responsible for confinement of radionuclides, if considered the most reactive phase -CSH- or called secondary phases. In this research the hydration products of cement are presented as well as its importance in the nuclear industry. The analysis and observation of the cement clinker and the hydration products on the manufactured pulps with two commercial cements resistant to sulphates was realized using the observation technique of solid X-ray diffraction and nuclear analytic techniques of Moessbauer spectroscopy and X-Ray Fluorescence. The results show the presence of calcium silicate hydrates in the amorphous phase and the presence of ettringite crystals and portlandite sheets is appreciated. The abundant iron phase called tetra calcium ferro aluminate has been identified by Moessbauer spectroscopy. (Author)

  12. Cement production from coal conversion residues

    International Nuclear Information System (INIS)

    Brown, L.D.; Clavenna, L.R.; Eakman, J.M.; Nahas, N.C.

    1981-01-01

    Cement is produced by feeding residue solids containing carbonaceous material and ash constituents obtained from converting a carbonaceous feed material into liquids and/or gases into a cement-making zone and burning the carbon in the residue solids to supply at least a portion of the energy required to convert the solids into cement

  13. Integral migration and source-term experiments on cement and bitumen waste forms

    International Nuclear Information System (INIS)

    Ewart, F.T.; Howse, R.M.; Sharpe, B.M.; Smith, A.J.; Thomason, H.P.; Williams, S.J.; Young, M.

    1986-01-01

    This is the final report of a programme of research which formed a part of the CEC joint research project into radionuclide migration in the geosphere (MIRAGE). This study addressed the aspects of integral migration and source term. The integral migration experiment simulated, in the laboratory, the intrusion of water into the repository, the leaching of radionuclides from two intermediate-level waste-forms and the subsequent migration through the geosphere. The simulation consisted of a source of natural ground water which flowed over a sample of waste-form, at a controlled redox potential, and then through backfill and geological material packed in columns. The two waste forms used here were cemented waste from the WAK plant at Karlsruhe in the Federal Republic of Germany and bitumenized intermediate concentrates from the Marcoule plant in France. The soluble fission products such as caesium were rapidly released from the cemented waste but the actinides, and technetium in the reduced state, were retained in the waste-form. The released of all nuclides from the bitumenized waste was very low

  14. Polymer-Cement Mortar with Quarry Waste as Sand Replacement

    Directory of Open Access Journals (Sweden)

    D. N. Gómez-Balbuena

    2018-01-01

    Full Text Available The activities of carved Quarry extraction generate problems of landscape pollution such is the case of solid waste discharged into open land dumps in central Mexico. This article presents the technological application of this solid waste in a new polymeric material with properties similar to those of a traditional mortar. It is concluded that the polymeric material uses low amounts of cement with respect to the traditional mortar, and it is elaborated with the recycled quarry as they are presented in its granulometry. The polymer used favored a low water/cement ratio (0.3 which did not allow to decrease resistance due to the fine nature of the materials (residues and cement in addition to maintaining the workability of the material. The quarry residue was classified as silt with low plasticity and was characterized by X-ray diffraction and Fluorescence to identify 76% of SiO2, which is why it was used as a stone aggregate even though the fines content was approximately 93%. The maximum compression resistance obtained at 28 days were 8 Mpa with the polymer/solid ratios of 0.10, water/solids of 0.30, and quarry/solids of 0.67. Linear equations were analyzed for more representative values with R squared adjustment.

  15. Physico Mechanical Properties of Irradiated Waste Rubber Cement Mortar

    International Nuclear Information System (INIS)

    Younes, M.M.

    2010-01-01

    In the present study a partial replacement of aggregate with two different ratios of waste rubber (5%, 10%) with the addition of a constant ratio of rice husk ash (RHA), 5% was carried out. The hardened cement mortar used the optimum water of consistency. The specimens were molded into 1 inch cubic moulds .The specimens were first cured for 24 hours, at 100% relative humidity and then cured under tap water for 3, 7 and 28 days followed by irradiation at different doses of gamma irradiation namely 5 and 10 kGy. The physico-chemical and mechanical properties such as compressive strength, total porosity and bulk density were studied for the three types of specimens. The results showed that the values of the compressive strength, bulk density and chemically combined water of the blended cement mortar paste (OPC-RHA) increase ,while blended cement mortar paste with 5% RHA and 5, 10% waste rubber decrease. The results were confirmed by scanning electron microscopy and thermal behavior of the specimens. Also, it was observed that the irradiated sample was thermally more stable than the unirradiated one

  16. Characterization of cement and bitumen waste forms containing simulated low-level waste incinerator ash

    International Nuclear Information System (INIS)

    Westsik, J.H. Jr.

    1984-08-01

    Incinerator ash from the combustion of general trash and ion exchange resins was immobilized in cement and bitumen. Tests were conducted on the resulting waste forms to provide a data base for the acceptability of actual low-level waste forms. The testing was done in accordance with the US Nuclear Regulatory Commission Technical Position on Waste Form. Bitumen had a measured compressive strength of 130 psi and a leachability index of 13 as measured with the ANS 16.1 leach test procedure. Cement demonstrated a compressive strength of 1400 psi and a leachability index of 7. Both waste forms easily exceed the minimum compressive strength of 50 psi and leachability index of 6 specified in the Technical Position. Irradiation to 10 8 Rad and exposure to 31 thermal cycles ranging from +60 0 ) to -30 0 C did not significantly impact these properties. Neither waste form supported bacterial or fungal growth as measured with ASTM G21 and G22 procedures. However, there is some indication of biodegradation due to co-metabolic processes. Concentration of organic complexants in leachates of the ash, cement and bitumen were too low to significantly affect the release of radionuclides from the waste forms. Neither bitumen nor cement containing incinerator ash caused any corrosion or degradation of potential container materials including steel, polyethylene and fiberglass. However, moist ash did cause corrosion of the steel

  17. Equilibrium leach tests with cobalt in the system cemented waste form/container material/aqueous solution

    International Nuclear Information System (INIS)

    Vejmelka, P.; Koester, R.; Lee, M. J.; Han, K. W.

    1991-01-01

    The equilibrium concentrations of Co in the system of cemented waste form/aqueous solutions were determined including the effect of the container material and its corrosion products under the respective conditions. The chemical conditions in the near field of the waste form were characterized by measurement of the pH and E h value. As disposal relevant solutions, saturated sodium chloride, Q-brine (main constituent MgCl 2 ) and a granitic type groundwater were used. For comparison, also experiments using deionized water were performed. In all systems investigated the cemented waste form itself has a strong influence on the chemical conditions in the near field. The pH and E h values are affected in all cases by the addition of the cemented waste form. There is no or only a slight difference between the E h values if iron powder or iron hydroxide is added to the cemented waste form/solution systems, but the E h is markedly decreased when iron powder is added to the solution free of cement. The Co concentration is decreased in all solutions by the addition of the cemented waste form, the largest effect is observed in Q-brine and this can be attributed either to the sorption of the Co-ions on the corrosion products of the cement or to the coprecipitation of Co-hydroxide and Mg-hydroxide. In the other solutions the Co concentration is decreased by precipitation of Co-hydroxide due to the high pH value of 12.5, and the concentrations are comparable for the different solutions

  18. Influence of industrial solid waste addition on properties of soil-cement bricks

    OpenAIRE

    Siqueira, F. B.; Amaral, M. C.; Bou-Issa, R. A.; Holanda, J. N. F.

    2016-01-01

    Abstract The reuse of pollutant solid wastes produced in distinct industrial activities (avian eggshell waste and welding flux slag waste) as a source of alternative raw material for producing soil-cement bricks for civil construction was investigated. Soil-cement bricks containing up to 30 wt% of industrial solid waste were uniaxially pressed and cured for 28 days. Special emphasis is given on the influence of solid waste addition on the technical properties (as such volumetric shrinkage, wa...

  19. Radiolytic gas generation from cement-based waste hosts for DOE low-level radioactive wastes

    International Nuclear Information System (INIS)

    Dole, L.R.; Friedman, H.A.

    1986-01-01

    Using cement-based immobilization binders with simulated radioactive waste containing sulfate, nitrate, nitrite, phosphate, and fluoride anions, the gamma- and alpha-radiolytic gas generation factors (G/sub t/, molecules/100 eV) and gas compositions were measured on specimens of cured grouts. These tests studied the effects of; (1) waste composition; (2) the sample surface-to-volume ratio; (3) the waste slurry particle size; and (4) the water content of the waste host formula. The radiolysis test vessels were designed to minimize the ''dead'' volume and to simulate the configuration of waste packages

  20. Solidification of low-level radioactive liquid waste using a cement-silicate process

    International Nuclear Information System (INIS)

    Grandlund, R.W.; Hayes, J.F.

    1979-01-01

    Extensive use has been made of silicate and Portland cement for the solidification of industrial waste and recently this method has been successfully used to solidify a variety of low level radioactive wastes. The types of wastes processed to date include fuel fabrication sludges, power reactor waste, decontamination solution, and university laboratory waste. The cement-silicate process produces a stable solid with a minimal increase in volume and the chemicals are relatively inexpensive and readily available. The method is adaptable to either batch or continuous processing and the equipment is simple. The solid has leaching characteristics similar to or better than plain Portland cement mixtures and the leaching can be further reduced by the use of ion-exchange additives. The cement-silicate process has been used to solidify waste containing high levels of boric acid, oils, and organic solvents. The experience of handling the various types of liquid waste with a cement-silicate system is described

  1. Effect of Ground Waste Concrete Powder on Cement Properties

    Directory of Open Access Journals (Sweden)

    Xianwei Ma

    2013-01-01

    Full Text Available The paste/mortar attached to the recycled aggregate decreases the quality of the aggregate and needs to be stripped. The stripped paste/mortar is roughly 20% to 50% in waste concrete, but relevant research is very limited. In this paper, the effects of ground waste concrete (GWC powder, coming from the attached paste/mortar, on water demand for normal consistency, setting time, fluidity, and compressive strength of cement were analyzed. The results show that the 20% of GWC powder (by the mass of binder has little effect on the above properties and can prepare C20 concrete; when the sand made by waste red clay brick (WRB replaces 20% of river sand, the strength of the concrete is increased by 17% compared with that without WRB sand.

  2. Characterization of low and intermediate level cemented waste forms

    International Nuclear Information System (INIS)

    Koester, R.; Vejmelka, P.; Brunner, H.; Ganser, B.

    1985-01-01

    The main objective of the characterization work was to establish source term formulations for the cemented waste forms as input for safety analysis. For the operation phase of a repository radionuclide mobilization from the waste packages via the gas phase, caused by mechanical or thermal impact has to be considered. For this reason, besides laboratory tests, experiments with inactive full scale samples were performed to determine quantitatively the activity release from the waste packages under defined thermal and mechanical stresses. In order to evaluate source terms for the mobilization of relevant radionuclides via the liquid phase as a function of time due to leaching and corrosion, detailed experimental work with simulated inactive and dopted laboratory samples and with inactive full scale samples was performed. The experimental work was accompanied by theoretical investigations to establish an improved basis for long term predictions. (orig./PW)

  3. An Experimental Study on Effect of Palm – Shell Waste Additive to Cement Strenght Enhancement

    Directory of Open Access Journals (Sweden)

    Adi Novriansyah

    2017-03-01

    Full Text Available Enhancing the cement strength through attaching chemical additive has been popular to meet the required condition for a particular well-cementing job. However, due to a low oil-price phenomenon, pouring and additive should be reconsidered because it can raise the cost and make the project become uneconomic. Another additive material in nanocomposite form will be introduced through this experimental study. The nanocomposite material consist of silica nanoparticle, known as “Nanosilica” and a palm-shell-waste, which is abundant in Indonesia. Before making a nanocomposite, the palm-shell should be burned to obtain a charcoal form, ground and sieved to attain a uniform size.   The study focuses on the two parameters, compressive strength and shear bond strength, which can reflect the strength of the cement. These values are obtained by performing a biaxial loading test to the cement sample. Various samples with different concentration of nanocomposite should be prepared and following the mixing, drying, and hardening process before the loading test is carried out. The result from the test shows a positive indication for compressive strength and shear bond strength values, according to the representative well cementing standards. Increasing the nanocomposite concentration on the cement will increase these values. Furthermore, an investigation on the temperature effect confirms that the sample with 700oC burning temperature have highest compressive-strength and shear-bond-strength values. This is a potential opportunity utilizing a waste-based material to produce another product with higher economic value.

  4. Cement conditioning of waste materials and polluted soil using the GEODUR process

    International Nuclear Information System (INIS)

    Brocdersen, K.; Hjelmar, O.; Mortonsen, S.

    1991-01-01

    In this paper two areas of application of the GEODUR additive in cement stabilization of waste materials have been investigated: stabilization of radioactive contaminated soil and stabilization of municipal solid waste incinerator ash. Preliminary experimental work on a clayey soil contaminated with radioactive cesium and strontium has indicated that the GEODUR process is a technically feasible method for soil solidification. The retarding effects of humic materials in the soil are eliminated by the additive even at low cement contents. The solidified soil is not particularly strong, but that satisfactory water permeability. Retention of cesium is reasonably good, but not as good as for the untreated soil. Retention of strontium is not good but is considerably improved by carbonation. The volume stability during permanent immersion of the solidified products in water is satisfactory, but crack formation during dryout cannot be excluded

  5. Physical and thermal behavior of cement composites reinforced with recycled waste paper fibers

    Science.gov (United States)

    Hospodarova, Viola; Stevulova, Nadezda; Vaclavik, Vojtech; Dvorsky, Tomas

    2017-07-01

    In this study, three types of recycled waste paper fibers were used to manufacture cement composites reinforced with recycled cellulosic fibers. Waste cellulosic fibers in quantity of 0.2, 0.3, and 0.5 wt.% were added to cement mixtures. Physical properties such as density, water capillarity, water absorbability and thermal conductivity of fiber cement composites were studied after 28 days of hardening. However, durability of composites was tested after their water storage up to 90 days. Final results of tested properties of fiber cement composites were compared with cement reference sample without cellulosic fibers.

  6. Recent advances in cement solidification of radioactive wastes

    International Nuclear Information System (INIS)

    Vigreux, B.; Jaouen, C.

    1987-01-01

    Advanced cement solidification processes and systems have been developed by SGN to meet changing requirements in radioactive waste processing and packaging and to avoid the difficulties often encountered in waste concreting on an industrial scale. SGN applies a strict development methodology to ensure integration of the most recent information on chemical behavior of solidified wastes plus compliance with the precise needs of waste producers and evolving regulatory requirements concerning waste package storage and disposal. Based on a hierarchical definition of objectives, this methodology was implemented following an overall study on radwaste concreting performed in 1983 and 1984 for Electricite de France (EdF), France's national electric power utility. It ensures that industrial and regulatory factors are fully considered from the start of development work. It also constrains development in the direction of true process optimization and guarantees compliance with defined objectives. The methodology has helped SGN develop concreting processes adapted to various types of radioactive waste. The most widely employed processes are first briefly described in this paper. It then presents continuous and batch systems using these processes, focusing on technological features chosen at a very early stage in development

  7. Influence of chemical composition of civil construction waste in the cement paste; Influencia da composicao quimica dos residuos da construcao civil a pasta de cimento

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, G.A.; Andrade, A.C.D.; Souza, J.M.M.; Evangelista, A.C.J.; Almeida, V.C., E-mail: valeria@eq.ufrj.b [Universidade Federal do Rio de Janeiro (EQ/UFRJ), RJ (Brazil). Escola de Quimica

    2009-07-01

    The construction and demolition waste when disposed inappropriately might cause serious public health problems. Its reutilization focusing on the development of new products using simple production techniques, assuring a new product life cycle and not damaging the environment is inserted in sustainable concept. The aim of this work was identifying the characteristics of types of waste generated in a residential reform (glassy ceramic and fill dirt leftovers) verifying separately its influence on cement pastes mechanical behavior. Cement pastes + wastes were prepared in 25% and 50% proportions with an approximately 0,35 water/cement relation and, glue time determination, water absorption, resistance to compression and X-ray fluorescence assays were taken. The results indicate that the chemical composition of the waste causes changes in the behavior of cement pastes, reflecting on their resistance to compression. (author)

  8. Modeling long-term leaching experiments of full scale cemented wastes: effect of solution composition on diffusion

    International Nuclear Information System (INIS)

    Borkel, C.; Montoya, V.; Kienzler, B.

    2015-01-01

    The code PHREECQ V3.1 has been used to simulate leaching experiments performed with cemented simulated waste products in tap water for more than 30 years. In this work the main focus is related with the leaching of Cs explained by diffusion processes. A simplifying model using the code PHREECQ V3.1 was used to investigate the influence of different parameters on the release of Cs from the cement solid to the leaching solution. The model setup bases on four main assumptions: a) the solid as well as the distribution of Cs is homogeneous and of isotropic texture, b) there is no preferential direction regarding cement degradation or water intrusion into the solid, c) the pore space is entirely connected and d) Cs adsorption to the cement or container is negligible. In the modeling the constraint of charge balance was stressed. Effective diffusion coefficients (D e ) were obtained analytically and from modeling the diffusive release of Cs from cemented waste simulates. The obtained values D e for Cs leaching are in perfect agreement with the values published in literature. Contradictory results to diffusive release were obtained from XRD analysis of the solids, suggesting that water may not have penetrated the cement monoliths entirely, but only to some centimeters depth. XRD analysis have been done to determine the solid phases present in cement and are used to help outlining strength and weaknesses of the different models

  9. Cement waste form development for ion-exchange resins and fine particles ILW of AREVA La Hague Reprocessing Plant

    International Nuclear Information System (INIS)

    Chartier, D.; Sanchez-Canet, J.; Avril, D.; Roussel, C.; Pineau, J.N.

    2015-01-01

    Wastes have been temporarily stored in dedicated silos in La Hague reprocessing plant. These wastes are to be retrieved in the near future and to be conditioned for final disposal. Some of these wastes are supposed to be encapsulated in cement matrix and, depending on the chemical composition of the waste streams, several projects are presently ongoing. The present article aims to focus on one amongst these cement encapsulation relevant projects, namely the conditioning of a mix of spent ion-exchange resins (from filtration of pool) and fine particles (insoluble fission products from spent fuel dissolution and Zircaloy and stainless steel fines from cladding shearing). The project, aims to retrieve these wastes from a silo, separate the resins and fine particles from the other waste (hulls and end pieces), in order to encapsulate the intermediate-level fines and resins in a cement matrix. The waste forms will be produced in AREVA's La Hague reprocessing plant, prior to being sent as intermediate-level waste to a long-term repository. The cement formulation developments were initially carried out at a small scale at C.E.A. Marcoule on surrogate wastes. One of the main issues that were considered was the chemical compatibility between waste and cement matrix. Indeed, swelling phenomena are sometimes reported when ion exchange resins are embedded in cement matrixes such as Portland cement. This kind of destructive phenomenon has been prevented by the use of cement containing a high amount of ground granulated blast furnace slag. The impact of the variability of ionic charge of the resins on the waste form's properties has also been addressed in order to comfort the results obtained on the reference ionic charge of resins NaNO 3 . Once the results obtained were satisfactory, intermediate scale and full scale tests were performed by AREVA. These tests have focused on adjusting the mixing process and controlling the thermal properties of the mix during setting

  10. The incorporation of low and medium level radioactive wastes (solids and liquids) in cement

    International Nuclear Information System (INIS)

    Brown, D.J.; Palmer, J.D.; Smith, D.L.

    1983-10-01

    The testing of cemented waste specimens containing sodium nitrate and sodium sulphate has been carried out over a period of two and a half years. One set of samples is kept under environmental conditions which simulate the anticipated storage conditions and a second series is stored under water. Additional results are reported here from the long-term stability testing of these simulated cemented wastes. Some applications of the method developed for measuring the apparent viscosity of cement pastes are described. Some preliminary information is given on the assessment of cement-waste mixing equipment. (U.K.)

  11. Behavior of cement paste as backfill in waste disposal boreholes

    International Nuclear Information System (INIS)

    Ferreira, Eduardo G.A.; Isiki, Vera L.K.; Miyamoto, Hissae; Marumo, Julio T.; Vicente, Roberto

    2011-01-01

    The Radioactive Waste Management Laboratory (GRR) at the Nuclear and Energy Research Institute (IPEN) in Sao Paulo, Brazil, is developing the concept a repository for disposition of disused sealed radioactive sources in a deep borehole, aiming at providing a feasible and inexpensive alternative for final disposal. A relevant fraction of the Brazilian inventory of sources has long half-life which prevents them to be disposed of in shallow ground disposal facilities. In the concept of repository under study, Portland cement paste is intended to be used as a backfill between the steel casing and the geological formation around the borehole. Cement paste will function as structural, an additional barrier against the migration of radionuclides outside the repository, and as a blockage against the transport of water between the different strata of the geological setting. The durability of cementitious materials under the conditions prevailing at the depth of disposal is as yet unknown. The objective of this research is to investigate the behavior of the cement paste and to estimate its service life. In this paper we present the results of mechanical strength measurements and chemical and mineralogical analysis of samples to detect the changes caused by radiation, temperature and aggressive chemicals present in ground water. Techniques of analysis included Inductively Coupled Plasma Atomic Emission Spectroscopy, Ion Chromatography, X-Ray Diffraction, and Thermo-Gravimetric Analysis. (author)

  12. Advanced technologies of production of cemented carbides and composite materials based on them

    International Nuclear Information System (INIS)

    Bondarenko, V.; Pavlotskaya, E.; Martynova, L.; Epik, I.

    2001-01-01

    The paper presents new technological processes of production of W, WC and (Ti, W)C powders, cemented carbides having a controlled carbon content, high-strength nonmagnetic nickel-bonded cemented carbides, cemented carbide-based composites having a wear-resistant antifriction working layer as well as processes of regeneration of cemented carbide waste. It is shown that these technological processes permit radical changes in the production of carbide powders and products of VK, TK, VN and KKhN cemented carbides. The processes of cemented carbide production become ecologically acceptable and free of carbon black, the use of cumbersome mixers is excluded, the power expenditure is reduced and the efficiency of labor increases. It becomes possible to control precisely the carbon content within a two-phase region -carbide-metal. A high wear resistance of parts of friction couples which are lubricated with water, benzine, kerosene, diesel fuel and other low-viscosity liquids, is ensured with increased strength and shock resistance. (author)

  13. Physical, chemical and mineralogical characterization of water treatment plant waste for use in soil-cement brick

    International Nuclear Information System (INIS)

    Pessin, L.R.; Destefani, A.Z.; Holanda, J.N.F.

    2011-01-01

    The water treatment plants (WTP) for human consumption generate huge amounts of waste in the form of sludge (sludge) that have been over the years mostly inadequately prepared in water resources and the environment. Moreover, traditional methods of disposal of waste water treatment plants commonly used are generally costly activities. An alternative method for disposal of this waste abundant is its incorporation in ceramic products. This work is focused on the physical-chemical and mineralogical composition of a sample of waste water treatment plants from the region of Campos dos Goytacazes-RJ to their use in the manufacture of soil-cement brick. Several characterization techniques were used including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, picnometry, particle size analysis and plasticity. The experimental results indicate that the waste water treatment plants have the potential to be used in the manufacture of ecologic soil-cement bricks. (author)

  14. The Transformation of Coal-Mining Waste Minerals in the Pozzolanic Reactions of Cements

    Directory of Open Access Journals (Sweden)

    Rosario Giménez-García

    2016-06-01

    Full Text Available The cement industry has the potential to become a major consumer of recycled waste materials that are transformed and recycled in various forms as aggregates and pozzolanic materials. These recycled waste materials would otherwise have been dumped in landfill sites, leaving hazardous elements to break down and contaminate the environment. There are several approaches for the reuse of these waste products, especially in relation to clay minerals that can induce pozzolanic reactions of special interest in the cement industry. In the present paper, scientific aspects are discussed in relation to several inert coal-mining wastes and their recycling as alternative sources of future eco-efficient pozzolans, based on activated phyllosilicates. The presence of kaolinite in this waste indicates that thermal treatment at 600 °C for 2 h transformed these minerals into a highly reactive metakaolinite over the first seven days of the pozzolanic reaction. Moreover, high contents of metakaolinite, together with silica and alumina sheet structures, assisted the appearance of layered double hydroxides through metastable phases, forming stratlingite throughout the main phase of the pozzolanic reaction after 28 days (as recommended by the European Standard as the reaction proceeded.

  15. Sulfur polymer cement, a solidification and stabilization agent for hazardous and radioactive wastes

    International Nuclear Information System (INIS)

    Darnell, G.R.

    1992-01-01

    Hydraulic cements have been the primary radioactive waste stabilization agents in the United States for 50 years. Twelve years ago, Brookhaven National Laboratory was funded by the Department of Energy's Defense Low-Level Waste Management Program to test and develop sulfur polymer cement (SPC). It has stabilized routine wastes as well as some troublesome wastes with high waste-to-agent ratios. The Department of Energy's Hazardous Waste Remedial Action Program joined the effort by providing funding for testing and developing sulfur polymer cement as a hazardous-waste stabilization agent. Sulfur polymer cement has passed all the laboratory scale tests required by the US Environmental Protection Agency and US Nuclear Regulatory Commission. Two decades of tests by the US Bureau of Mines and private concrete contractors indicate this agent is likely to exceed other agents in longevity. This bulletin provides technical data from pertinent tests conducted by these various entities

  16. Long Term Behaviour Evaluation of Cement Conditioning Matrices Used for Management of Radioactive Wastes at IFIN-HH

    International Nuclear Information System (INIS)

    Dragolici, F.

    2013-01-01

    The mechanical and structural characterization of the radioactive waste conditioning matrix is very important during the final disposal stage in the radioactive waste management cycle. The conditioning products should be a monolith with acceptable mechanical, chemical and physical properties that are maintained over an appropriate time such that the release of radioactivity from the waste form in the environment is minimized. The aim of this work is the XRD application for the phase identification of matrix that simulates the conditioned radioactive waste and the correlation with mechanical performance. The selected matrices for the study are normal cement with iron precipitates (hydroxide and phosphate), mineral additives (bentonite and volcanic tuff) and complexing agents (tartaric, citric and oxalic acids). The results obtained by this analysis give information about the chemical reactions between the radioactive precipitates and the hydrates, hydrolysis products of the cement. (author)

  17. Sets of Reports and Articles Regarding Cement Wastes Forms Containing Alpha Emitters that are Potentially Useful for Development of Russian Federation Waste Treatment Processes for Solidification of Weapons Plutonium MOX Fuel Fabrication Wastes for

    International Nuclear Information System (INIS)

    Jardine, L J

    2003-01-01

    This is a set of nine reports and articles that were kindly provided by Dr. Christine A. Langton from the Savannah River Site (SRS) to L. J. Jardine LLNL in June 2003. The reports discuss cement waste forms and primarily focus on gas generation in cement waste forms from alpha particle decays. However other items such as various cement compositions, cement product performance test results and some cement process parameters are also included. This set of documents was put into this Lawrence Livermore National Laboratory (LLNL) releasable report for the sole purpose to provide a set of documents to Russian technical experts now beginning to study cement waste treatment processes for wastes from an excess weapons plutonium MOX fuel fabrication facility. The intent is to provide these reports for use at a US RF Experts Technical Meeting on: the Management of Wastes from MOX Fuel Fabrication Facilities, in Moscow July 9-11, 2003. The Russian experts should find these reports to be very useful for their technical and economic feasibility studies and the supporting R and D activities required to develop acceptable waste treatment processes for use in Russia as part of the ongoing Joint US RF Plutonium Disposition Activities

  18. Utilization of small-angle neutron scattering to decide the maximum loading of nuclear waste in cement matrix

    International Nuclear Information System (INIS)

    Das, Avik; Mazumder, S.; Sen, D.; Yalmali, V.; Shah, J.G.

    2014-01-01

    Nuclear power plants generate many kinds of hazardous nuclear waste which are needed to be disposed in an eco-friendly manner. Many different waste incarceration techniques have been adapted for managing the nuclear waste of different category of radioactivity. Immobilisation of low and intermediate level radioactive wastes in cement matrix is one of the widely used and cost-effective techniques in waste management. However, loading of nuclear waste in cement matrix can alter the mesoscopic structure of the hydrated cement and hence, it is very important to set the maximum limit of waste loading in cement for providing proper physical isolation to the nuclear waste

  19. HYDRATION AND PROPERTIES OF BLENDED CEMENT SYSTEMS INCORPORATING INDUSTRIAL WASTES

    Directory of Open Access Journals (Sweden)

    Heikal M.

    2013-06-01

    Full Text Available This paper aims to study the characteristics of ternary blended system, namely granulated blast-furnace slag (WCS, from iron steel company and Homra (GCB from Misr Brick (Helwan, Egypt and silica fume (SF at 30 mass % pozzolanas and 70 mass % OPC. The required water of standard consistency and setting times were measured as well as physico-chemical and mechanical characteristics of the hardened cement pastes were investigated. Some selected cement pastes were tested by TGA, DTA and FT-IR techniques to investigate the variation of hydrated products of blended cements. The pozzolanic activity of SF is higher than GCB and WCS. The higher activity of SF is mainly due to its higher surface area than the other two pozzolanic materials. On the other side, GCB is more pozzolanic than WCS due to GCB containing crystalline silica quartz in addition to an amorphous phase. The silica quartz acts as nucleating agents which accelerate the rate of hydration in addition to its amorphous phase, which can react with liberating Ca(OH2 forming additional hydration products.

  20. Particular provisions applicable to the production, inspection, treatment, packaging and interim storage of wastes immobilized in cement, resulting from the reprocessing of fuels irradiated in pressurized light water reactors

    International Nuclear Information System (INIS)

    1985-02-01

    The Fundamental Safety Rules applicable to certain types of nuclear installation are intended to clarify the conditions of which observance, for the type of installation concerned and for the subject that they deal with, is considered as equivalent to compliance with regulatory French technical practice. These Rules should facilitate safety analysises and the clear understanding between persons interested in matters related to nuclear safety. They in no way reduce the operator's liability and pose no obstacle to statutory provisions in force. For any installation to which a Fundamental Safety Rule applies according to the foregoing paragraph, the operator may be relieved from application of the Rule if he shows proof that the safety objectives set by the Rule are attained by other means that he proposes within the framework of statutory procedures. Furthermore, the Central Service for the Safety of Nuclear Installations reserves the right at all times to alter any Fundamental Safety Rule, as required, should it deem this necessary, while specifying the applicability conditions. This rule is intended to stipulate the specific provisions applicable to the production, inspection, treatment, packaging and interim storage of the wastes, resulting from the reprocessing of fuels irradiated in a PWR and immobilized in cement

  1. Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment.

    Science.gov (United States)

    Clancy, Tara M; Snyder, Kathryn V; Reddy, Raghav; Lanzirotti, Antonio; Amrose, Susan E; Raskin, Lutgarde; Hayes, Kim F

    2015-12-30

    Cement stabilization of arsenic-bearing wastes is recommended to limit arsenic release from wastes following disposal. Such stabilization has been demonstrated to reduce the arsenic concentration in the Toxicity Characteristic Leaching Procedure (TCLP), which regulates landfill disposal of arsenic waste. However, few studies have evaluated leaching from actual wastes under conditions similar to ultimate disposal environments. In this study, land disposal in areas where flooding is likely was simulated to test arsenic release from cement stabilized arsenic-bearing iron oxide wastes. After 406 days submersed in chemically simulated rainwater, wastes. Presenting the first characterization of cement stabilized waste using μXRF, these results revealed the majority of arsenic in cement stabilized waste remained associated with iron. This distribution of arsenic differed from previous observations of calcium-arsenic solid phases when arsenic salts were stabilized with cement, illustrating that the initial waste form influences the stabilized form. Overall, cement stabilization is effective for arsenic-bearing wastes when acidic conditions can be avoided. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. ALKALI-ACTIVATED CEMENT MORTARS CONTAINING RECYCLED CLAY-BASED CONSTRUCTION AND DEMOLITION WASTE

    Directory of Open Access Journals (Sweden)

    F. Puertas

    2015-09-01

    Full Text Available The use of clay-based waste as an aggregate for concrete production is an amply studied procedure. Nonetheless, research on the use of this recycled aggregate to prepare alkaline cement mortars and concretes has yet to be forthcoming. The present study aimed to determine: the behaviour of this waste as a pozzolan in OPC systems, the mechanical strength in OPC, alkali-activated slag (AAS and fly ash (AAFA mortars and the effect of partial replacement of the slag and ash themselves with ground fractions of the waste. The pozzolanic behaviour of clay-based waste was confirmed. Replacing up to 20 % of siliceous aggregate with waste aggregate in OPC mortars induced a decline in 7 day strength (around 23 wt. %. The behaviour of waste aggregate in AAMs mortars, in turn, was observed to depend on the nature of the aluminosilicate and the replacement ratio used. When 20 % of siliceous aggregate was replaced by waste aggregate in AAS mortars, the 7 day strength values remained the same (40 MPa. In AAFA mortars, waste was found to effectively replace both the fly ash and the aggregate. The highest strength for AAFA mortars was observed when they were prepared with both a 50 % replacement ratio for the ash and a 20 % ratio for the aggregate.

  3. Testing and evaluation of alternative process systems for immobilizing radioactive mixed particulate waste in cement

    International Nuclear Information System (INIS)

    Weingardt, K.M.; Weber, J.R.

    1994-03-01

    Radioactive and Hazardous Mixed Wastes have accumulated at the Department of Energy (DOE) Hanford Site in south-central Washington State. Ongoing operations and planned facilities at Hanford will also contribute to this waste stream. To meet the Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions most of this waste will need to be treated to permit disposal. In general this treatment will need to include stabilization/solidification either as a sole method or as part of a treatment train. A planned DOE facility, the Waste Receiving and Processing (WRAP) Module 2A, is scoped to provide this required treatment for containerized contact-handled (CH), mixed low-level waste (MLLW) at Hanford. An engineering development program has been conducted by Westinghouse Hanford Company (WHC) to select the best system for utilizing a cement based process in WRAP Module 2A. Three mixing processes were developed for analysis and testing; in-drum mixing, continuous mixing, and batch mixing. Some full scale tests were conducted and 55 gallon drums of solidified product were produced. These drums were core sampled and examined to evaluate mixing effectiveness. Total solids loading and the order of addition of waste and binder constituents were also varied. The highest confidence approach to meet the WRAP Module 2A waste immobilization system needs appears to be the out-of-drum batch mixing concept. This system is believed to offer the most flexibility and efficiency, given the highly variable and troublesome waste streams feeding the facility

  4. Study of the sulphate expansion phenomenon in concrete: behaviour of the cemented radioactive wastes containing sulphate

    International Nuclear Information System (INIS)

    Li, Guanshu

    1994-01-01

    Sulphate attack is one of the major degradation processes of concrete. It is especially important in storing cemented radioactive wastes containing sulphate. In this thesis, we have thoroughly investigated the degradation mechanisms of cemented radioactive wastes by sulphate. The CaO-Al 2 O 3 -SO 3 -H 2 O systems with and without alkalis are studied. For the system without alkalis, experimental results show that it is the formation of a secondary ettringite under external water supply by steric effect that causes the expansion. For the system with alkalis, the ettringite does not appear while a new mineral called 'U', a sodium-substituted AFm phase is detected. This phase is shown to be responsible for the expansion and destruction of the specimens. The conditions for the formation, the product of solubility and many means of its synthesis are discussed, and a complete list of the inter-reticular distances file is given. The behaviour of the different types of cemented wastes containing sulphate are then studied with a special focus on the U phase on entity which was heretofore very little understood. The following three hypothetical mechanisms of sulphate expansion are proposed: the formation of the secondary U phase, the transformation of the U phase to the ettringite and the topochemical hydration of thenardite into mirabilite. Experiments on a simplified system have demonstrated clearly that the formation of the secondary U phase can induce enormous expansion by steric effect, this justifying the first assumption. Simulation by the mass and volume balances is carried out thereafter and enables us to estimate the expansion induced by the formation of the secondary U phase in the cemented wastes. The second assumption is also well verified by a series of leaching tests in different solutions on mixtures containing the U phase. On the basis of the analysis of the specimens under leaching, it has been assumed that the expansion is associated with the

  5. Influence of superplasticizers on the long-term properties of cement pastes and possible impact on radionuclide uptake in a cement-based repository for radioactive waste

    International Nuclear Information System (INIS)

    Wieland, E.; Lothenbach, B.; Glaus, M.A.; Thoenen, T.; Schwyn, B.

    2014-01-01

    Highlights: • We investigate the hydration of different cement mixes containing concrete admixtures. • The concentration of concrete admixtures decreases with time due to sorption on cement phases. • We observe no influence on the phase composition of cement paste and the ion composition of pore fluids. • Uptake of 63 Ni, 152 Eu and 228 Th by cement paste is not affected by the concrete admixtures. - Abstract: Cementitious materials will be used for the construction of the engineered barrier of the planned repositories for radioactive waste in Switzerland. Superplasticizers (SPs) are commonly used to improve the workability of concretes and, along with a set accelerator (Acc), to produce shotcrete. In this study the influence of a polycarboxylate- (PCE) and a polynaphthalene-sulphonate-based (PNS) SP on the hydration process, mineral composition and the sorption behaviour of metal cations has been investigated using an ordinary Portland cement (OPC), a low-alkali cement mix (LAC) consisting of CEM III-type cement and nanosilica, and a shotcrete-type cement mix (ESDRED) consisting of a CEM I-type cement and silica fume prepared in the presence of an alkali-free set accelerator. Both the PCE and PNS SP do not significantly influence the amount and quantity of hydrates formed during hydration. The concentration of both SPs decreased rapidly in the early stage of the hydration process for all cements due to sorption onto cement phases. After 28 days of hydration and longer, the concentration of the PNS SP in the pore fluids of all cements was generally lower than that of the PCE SP, indicating stronger uptake of the PNS SP. The formate present in the Acc sorbs only weakly onto the cement phases, which led to higher aqueous concentration of organics in the ESDRED cement than in OPC and LAC. Sorption experiments with 63 Ni, 152 Eu and 228 Th on a cation exchange resin indicate that, at concentrations above 0.1 g L −1 , the two SPs could reduce sorption of metal

  6. Strength improvement of fibre cement product

    Directory of Open Access Journals (Sweden)

    Waranya Sonphuak

    2013-10-01

    Full Text Available This paper presents a methodology to improve the strength or the Modulus of Rupture (MOR of fibre cement. The Six Sigma approach with the DMAIC steps was applied to a case study company. This research started from defining problem, setting the project objective and the project scope. Next, the measurement system was analyzed and the process map was set up. The potential factors of the problem was then determined. Due to there were many factors that affect the MOR, the Cause and Effect Matrix and the Failure Mode and Effect Analysis technique were then used to reduce the number of factors to be studied further. Next, three process factors, which were the pulp slurry freeness, the film-layer thickness, and the pressure step, were optimized using the results from the Box-Behnken experimental design. Other 13 remaining factors were improved by creating or revising the standard work instructions and training the operators. After that, the statistical process control and the control plan were set up to control the production processes. After improvement, the process capability index (Ppk significantly increased from 0.26 to 1.35.

  7. Mechanical and chemical properties of polyvinyl alcohol modified cement mortar with silica fume used as matrix including radioactive waste

    International Nuclear Information System (INIS)

    Dakroury, A. M.

    2007-01-01

    This paper discussed the mechanical and chemical properties of polyvinyl alcohol - modified cement mortar with silica fume to assess the safety for disposal of radioactive waste. The modified cement mortars containing polyvinyl alcohol (PVA) in the presence of 10 % silica fume (SF) .The chemical reaction between polymer and cement - hydrated product were investigated by the Infrared Spectral Technology, Differential Thermal Analysis and X-ray diffraction. The leaching of 137Cs from a waste composite into a surrounding fluid has been studied .The results shown that PVA increases the strength and decreases the porosity. The increase in strength duo to the interaction of PVA with cement , may be forming some new compound that fill the pores or improve the bond between the cement . The pozzolanic reaction of the SF increases the calcium silicate hydrates in the hardening matrix composites. There is distinct change in the refinement of the pore structure in cement composites giving fewer capillary pores and more of the finer gel pores

  8. The fundamentals of the radiation thermal technology for cement production

    International Nuclear Information System (INIS)

    Abramson, I.G.; Kapralova, R.M.; Nikiforov, Yu.V.; Egorov, G.B.; Vaisman, A.F.

    1995-01-01

    The fundamentals of principally new radiation thermal way of cement production are presented. The peculiarities of qualities and structure of clinker obtained by this way are given. The technical economic advantages of the new technology are shown

  9. Cement-free Binders for Radioactive Waste Produced from Blast-furnace Slag using Vortex Layer Activation Technology

    Directory of Open Access Journals (Sweden)

    Mazov Ilya

    2017-01-01

    Full Text Available The paper addresses the issue of recycling granulated blast-furnace slag (gBFS as a source for production of cement-free binder materials for further usage in rare-earth metals production for radioactive waste disposal. The use of the vortex layer activator was provided as main technique allowing to produce high-dispersed chemically activated binders. The paper examines the effect of processing conditions on the physical-chemical and mechanical properties of the resulting BFS-based cement-free materials and gBFS-based concretes.

  10. Formulation of portland composite cement using waste glass as a supplementary cementitious material

    Science.gov (United States)

    Manullang, Ria Julyana; Samadhi, Tjokorde Walmiki; Purbasari, Aprilina

    2017-09-01

    Utilization of waste glass in cement is an attractive options because of its pozzolanic behaviour and the market of glass-composite cement is potentially available. The objective of this research is to evaluate the formulation of waste glass as supplementary cementitious material (SCM) by an extreme vertices mixture experiment, in which clinker, waste glass and gypsum proportions are chosen as experimental variables. The composite cements were synthesized by mixing all of powder materials in jar mill. The compressive strength of the composite cement mortars after being cured for 28 days ranges between 229 to 268 kg/cm2. Composite cement mortars exhibit lower compressive strength than ordinary Portland cement (OPC) mortars but is still capable of meeting the SNI 15-7064-2004 standards. The highest compressive strength is obtained by shifting the cement blend composition to the direction of increasing clinker and gypsum proportions as well as reducing glass proportion. The lower compressive strength of composite cement is caused by expansion due to ettringite and ASR gel. Based on the experimental result, the composite cement containing 80% clinker, 15% glass and 5% gypsum has the highest compressive strength. As such, the preliminary technical feasibility of reuse of waste glass as SCM has been confirmed.

  11. Cementation and solidification of miscellaneous mixed wastes at the Rocky Flats Environmental Technology Site

    International Nuclear Information System (INIS)

    Phillips, J.A.; Semones, G.B.

    1995-01-01

    The Rocky Flats Environmental Technology Site produces a variety of wastes which are amenable to micro-encapsulation in cement Portland cement is an inexpensive and readily available material for this application. The Waste Projects (WP) group at Rocky Flats evaluated cementation to determine its effectiveness in encapsulating several wastes. These included waste analytical laboratory solutions, incinerator ash, hydroxide precipitation sludge, and an acidic solution from the Delphi process (a chemical oxidation technology being evaluated as an alternative to incineration). WP prepared surrogate wastes and conducted designed experiments to optimize the cement formulation for the waste streams. These experiments used a Taguchi or factorial experimental design, interactions between the variables were also considered in the testing. Surrogate waste samples were spiked with various levels of each of six Resource Conservation and Recovery Act (RCRA) listed metals (Cd, Cr, Ba, Pb, Ni, and Ag), cemented using the optimized formulation, and analyzed for leach resistance using the Toxicity Characteristic Leaching Procedure (TCLP). The metal spike levels chosen were based on characterization data, and also based on an estimate of the highest levels of contaminants suspected in the waste. This paper includes laboratory test results for each waste studied. These include qualitative observations as well as quantitative data from TCLP analyses and environmental cycling studies. The results from these experiments show that cement stabilization of the different wastes can produce final waste forms which meet the current RCRA Land Disposal Restriction (LDR) requirements. Formulations that resulted in LDR compliant waste forms are provided. The volume increases associated with cementation are also lower than anticipated. Future work will include verification studies with actual mixed radioactive waste as well as additional formulation development studies on other waste streams

  12. Cement-based grouts in geological disposal of radioactive waste

    International Nuclear Information System (INIS)

    Onofrei, M.

    1996-01-01

    The behavior and performance of a specially developed high-performance cement-based grout has been studied through a combined laboratory and in situ research program conducted under the auspices of the Canadian Nuclear Fuel Waste Management Program (CNFWMP). A new class of cement-based grouts - high-performance grouts-with the ability to penetrate and seal fine fractures was developed and investigated. These high-performance grouts, which were injected into fractures in the granitic rock at the Underground Research Laboratory (URL) in Canada, are shown to successfully reduce the hydraulic conductivity of the rock mass from -7 m s -1 to 10 -9 m s -1 and to penetrate fissures in the rock with apertures as small as 10 μm. Furthermore, the laboratory studies have shown that this high - performance grout has very low hydraulic conductivity and is highly leach resistant under repository conditions. Microcracks generated in this materials from shrinkage, overstressing or thermal loads are likely to self-seal. The results of these studies suggest that the high-performance grouts can be considered as viable materials in disposal-vault sealing applications. Further work is needed to fully justify extrapolation of the results of the laboratory studies to time scales relevant to performance assessment

  13. Carbon-14 behavior in a cement-dominated environment: Implications for spent CANDU resin waste disposal

    International Nuclear Information System (INIS)

    Dayal, R.; Reardon, E.J.

    1994-01-01

    Cement based waste forms and concrete engineered barriers are expected to play a key role in providing 14 C waste containment and control 14 C migration for time periods commensurate with its hazardous life of about 50,000 years. The main thrust of this study was, therefore, to evaluate the performance of cement based waste forms with regard to 14 C containment. Of particular importance are the geochemical processes controlling 14 C solubility and release under anticipated cement dominated low and intermediate level waste repository conditions. Immobilization of carbonate-form exchange resin in grout involves transfer of sorbed 14 CO 3 2- ions, through exchange for hydroxyl ions from the grout slurry, followed by localized precipitation of solid calcium carbonate at the cement/resin interface in the grout matrix. Carbon-14 release behavior can be attributed to the dissolution characteristics and solubility of calcite present in the cement based waste form. The groundwater flow regime can exert a pronounced effect both on the near-field chemistry and the leaching behavior of 14 C. For a cement dominated repository, at relatively low-flow or stagnant groundwater conditions, the alkaline near-field chemical environments inhibits the release of 14 C from the cemented waste form. Under high flow conditions, the near-field environment is characterized by relatively neutral pH conditions which promote calcite dissolution, thus resulting in 14 C release from the waste form

  14. Cementation of liquid radioactive waste with high content of borate salts

    International Nuclear Information System (INIS)

    Gorbunova, O.

    2015-01-01

    The report reviews the ways of optimization of cementation of boron-containing liquid radioactive waste. The most common way to hardening the low-level liquid radioactive waste (LRW) is the cementation. However, boron-containing liquid radioactive waste with low pH values cannot be cemented without alkaline additives, to neutralize acid forms of borate compounds. Cement setting without additives happens only on 14-56 days, the compounds have low strength, and hence an insufficient reliability of radionuclides fixation in the cement matrix. The alkaline additives increase the volume of the final cement compound which enhances financial and operational costs. In order to control the speed of hardening of cement solution with a boron-containing liquid radioactive waste and to remove the components that prevent hardening of cement solution, it is proposed an electromagnetic treatment of LRW in the vortex layer of ferromagnetic particles. The results of infrared spectroscopy show, that electromagnetic treatment of liquid radioactive waste changes the ionic forms of the borates and raises the pH due to the dissociation of the oxygen and hydrogen bonds in the aqueous solutions of the boron compounds. The various types of ferromagnetic activators of the vortex layer have been investigated, including the highly dispersed nano-powders and the magnetic phases of the iron oxides. It has been determined the technological parameters of the electromagnetic treatment of liquid radioactive waste and the subsequent cementation of this type of LRW. By using the method of scanning electron microscopy it has been shown, that the nano-particles of magnetic phases of the ferric oxides are involved in phase formation of hydro-aluminum-calcium ferrites in the early stages of hardening and improving strength of the cement compounds with liquid radioactive waste. (authors)

  15. Analysis by X-Ray images of EVA waste incorporated in Portland Cement

    International Nuclear Information System (INIS)

    Marques, M.A.; Antunes, M.L.P.; Montagnoli, R.M.; Mancini, S.D.

    2012-01-01

    The EVA is a copolymer used by Brazilian shoes industries. This material is cut for the manufacture of insoles. This operation generates about 18% of waste. The EVA waste can be reused in incorporation in Portland cement to construction without structural purposes. The aim of this work is to show X-rays images to assessment the space distribution of the wastes in the cement and to evaluate the use of this methodology. Cylindrical specimens were produced according to ABNT - NBR 5738 standards. The volume relation of sand and cement was 3:1, 10% and 30% of waste was incorporated in cement specimens. X-Rays images were obtained of cylindrical specimens in front projection. The images showed that the distribution of the waste is homogeneous, consistent with what was intended in this type of incorporation, which can provide uniformity in test results of compressive strength. (author)

  16. Method of cement-solidification of radioactive liquid wastes containing surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Y; Yusa, H

    1979-04-10

    Purpose: To provide the subject method comprising the steps of adjusting the concentration of the surfactant to a value less than the predetermined value even when the concentration of the surfactant is high, and rendering the uniaxial compression strength of the cement-solidification body into more than the defined fabrication reference value. Method: To radioactive liquid wastes there are applied means for boiling and heating liquid wastes by addition of sulfuric acid, means for cracking surfactants by the addition of oxidants and means for precipitating and arresting surfactants. After suppressing the hindrance of the cement hydration reaction by surfactants, the radioactive liquid wastes are cement-solidified. (Nakamura, S.).

  17. The sorption and mechanical properties of the modified cement matrix used for conditioning of radioactive waste

    International Nuclear Information System (INIS)

    Dogaru, Daniela; Nuculae, Ortenzia; Jinescu, Gheorghita; Duliu, Octavian; Dogaru, Gheorghe

    2008-01-01

    Full text: Radioactive contaminant sorption onto concrete represents one of the most important retardation mechanisms in engineered barriers such as the conditioning matrix itself, concrete walls and concrete floors. During the life of a disposal facility for radioactive waste, the sorption properties as well as the mechanical properties of the cement are affected by both external and internal processes. The most important sorbing material present in concrete is the hydrated cement. The sorption data obtained for specific cement or cement mixes in general may be used to characterize a given cement type. In order to improve the mechanical and sorption properties of the cement matrix, different additives were used in the laboratory tests. The used additives are known to have good sorption properties. The paper describes the influence of the concentration of additives on the mechanical and sorption properties of the cement matrix. As radioactive contaminants 134 Cs, 60 Co, 3 H, 241 Am were used. (authors)

  18. Physicochemical changes of cements by ground water corrosion in radioactive waste storage

    International Nuclear Information System (INIS)

    Contreras R, A.; Badillo A, V. E.; Robles P, E. F.; Nava E, N.

    2009-10-01

    Knowing that the behavior of cementations materials based on known hydraulic cement binder is determined essentially by the physical and chemical transformation of cement paste (water + cement) that is, the present study is essentially about the cement paste evolution in contact with aqueous solutions since one of principal risks in systems security are the ground and surface waters, which contribute to alteration of various barriers and represent the main route of radionuclides transport. In this research, cements were hydrated with different relations cement-aqueous solution to different times. The pastes were analyzed by different solid observation techniques XRD and Moessbauer with the purpose of identify phases that form when are in contact with aqueous solutions of similar composition to ground water. The results show a definitive influence of chemical nature of aqueous solution as it encourages the formation of new phases like hydrated calcium silicates, which are the main phases responsible of radionuclides retention in a radioactive waste storage. (Author)

  19. Joint Cementation of liquid and solid radioactive waste in decommissioning of atomic objects

    International Nuclear Information System (INIS)

    Varlakov, A.; Varlakova, G.; Germanov, A.; Sukhanov, L.

    2015-01-01

    Joint cementation of liquid and solid radioactive waste (RW) directly in the containers that serve as the final packaging allows the reduction of waste amounts sent for storage and disposal. In the A.A. Bochvar Research Institute we have created a mobile unit and conducted tests on joint grouting of solid RW with the use of cement mixtures prepared on the basis of liquid RW. Two variants of void filling between the fragments of solid RW in a container: pouring and impregnation were examined. Impregnation is the so-called method suggested to be used for the solid RW with small fragments and dense filling layer. In this case the gaps between the waste are filled with the cement compound by using special technological procedures, in particular, the vibration action on the container filled with waste and the use of cement mixture with high level of penetration. It was observed that the pouring method is right for the cementation of solid RW with fragment sizes not exceeding 100-150 mm. Impregnation method can be used for the joint grouting of practically all types of solid RW regardless their size and fragments homogeneity. Cementation of densely packed and large size solid RW by impregnation guarantees the joint grouting of the lower layers of the waste in the container and can be controlled by determination of the impregnation degree and density of the cement mixture that passed through the waste layer

  20. Study of incorporation of casting wastes in soil-cement blocks

    International Nuclear Information System (INIS)

    Folmann, R.; Malkowski, W.; Valentina, L.V.D.; Folgureras, M.V.

    2011-01-01

    Soil-cement bricks are an ecological alternative to conventional ones because they don't need to be burned to gain strength. This study examines the technical possibility of reuse of foundry sand as fine aggregate in soil-cement. The raw materials were characterized by X-ray diffraction, thermal analysis and particle size. The foundry sand wastes were mixed at different levels to soil and cement. Compaction tests were performed to define the mixtures at optimum moisture content corresponding to the maximum density. Isothermal Conduction Calorimeter was performed to study the influence of waste in the cement hydration reaction. The results indicate that the addition of foundry sand waste decreases the optimum moisture content and increases the maximum density without significantly affecting the cement set. (author)

  1. Evaluation of leaching behavior and immobilization of zinc in cement-based solidified products

    Directory of Open Access Journals (Sweden)

    Krolo Petar

    2012-01-01

    Full Text Available This study has examined leaching behavior of monolithic stabilized/solidified products contaminated with zinc by performing modified dynamic leaching test. The effectiveness of cement-based stabilization/solidification treatment was evaluated by determining the cumulative release of Zn and diffusion coefficients, De. The experimental results indicated that the cumulative release of Zn decreases as the addition of binder increases. The values of the Zn diffusion coefficients for all samples ranged from 1.210-8 to 1.1610-12 cm2 s-1. The samples with higher amounts of binder had lower De values. The test results showed that cement-based stabilization/solidification treatment was effective in immobilization of electroplating sludge and waste zeolite. A model developed by de Groot and van der Sloot was used to clarify the controlling mechanisms. The controlling leaching mechanism was found to be diffusion for samples with small amounts of waste material, and dissolution for higher waste contents.

  2. Stabilization of high and low solids Consolidated Incinerator Facility (CIF) waste with super cement

    International Nuclear Information System (INIS)

    Walker, B.W.

    2000-01-01

    This report details solidification activities using selected Mixed Waste Focus Area technologies with the High and Low Solid waste streams. Ceramicrete and Super Cement technologies were chosen as the best possible replacement solidification candidates for the waste streams generated by the SRS incinerator from a list of several suggested Mixed Waste Focus Area technologies. These technologies were tested, evaluated, and compared to the current Portland cement technology being employed. Recommendation of a technology for replacement depends on waste form performance, process flexibility, process complexity, and cost of equipment and/or raw materials

  3. The effect of chemically adjusting cement compositions on leachabilities of waste ions

    International Nuclear Information System (INIS)

    Barnes, M.W.; Scheetz, B.E.; Roy, D.M.

    1986-01-01

    The chemical composition of both portland and aluminate cements was adjusted by adding amorphous silica. In the case of portland cement, the object was to react with excess portlandite and obtain an overall composition compatible with C-S-H gel or C-S-H gel + silica at low temperatures, and to obtain the tobermorite composition in order to be in equilibrium with this phase at temperatures above normal ambient. In the case of aluminate cement, the object was to be in equilibrium with more silica-rich phases. These silica-adjusted cements were used to make composites with nuclear waste forms. Leach tests showed that the silica-adjusted composites were chemically more stable than those made with as-received cement. Leach rates were lower in the case of the adjusted cements for Rb, Cs, Ca, Sr, Ba, La, Ce, Nd, Gd, Al, and Si. Only Na in the case of both portland and aluminate cements, and Mg and U in the case of aluminate cements, had greater leach rates in adjusted cements. Adjusting the composition of cements with silica is concluded to be beneficial when making composites to encapsulate nuclear waste forms

  4. Potential use of pyrite cinders as raw material in cement production: results of industrial scale trial operations.

    Science.gov (United States)

    Alp, I; Deveci, H; Yazici, E Y; Türk, T; Süngün, Y H

    2009-07-15

    Pyrite cinders, which are the waste products of sulphuric acid manufacturing plants, contain hazardous heavy metals with potential environmental risks for disposal. In this study, the potential use of pyrite cinders (PyCs) as iron source in the production of Portland cement clinker was demonstrated at the industrial scale. The chemical and mineralogical analyses of the PyC sample used in this study have revealed that it is essentially a suitable raw material for use as iron source since it contains >87% Fe(2)O(3) mainly in the form of hematite (Fe(2)O(3)) and magnetite (Fe(3)O(4)). The samples of the clinkers produced from PyC in the industrial scale trial operation of 6 months were tested for the conformity of their chemical composition and the physico-mechanical performance of the resultant cement products. The data were compared with the clinker products of the iron ore, which is used as the raw material for the production Portland cement clinker in the plant. The chemical compositions of all the clinker products of PyC appeared to conform to those of the iron ore clinker, and hence, a Portland cement clinker. The mechanical performance of the mortars prepared from the PyC clinker was found to be consistent with those of the industrial cements e.g. CEM I type cements. It can be inferred from the leachability tests (TCLP and SPLP) that PyC could be a potential source of heavy metal pollution while the mortar samples obtained from the PyC clinkers present no environmental problems. These findings suggest that the waste pyrite cinders can be readily used as iron source for the production of Portland cement. The availability of PyC in large quantities at low cost provides further significant benefits for the management/environmental practices of these wastes and for the reduction of mining and processing costs of cement raw materials.

  5. Analysis of Cement-Based Pastes Mixed with Waste Tire Rubber

    Science.gov (United States)

    Sola, O. C.; Ozyazgan, C.; Sayin, B.

    2017-03-01

    Using the methods of thermal gravimetry, differential thermal analysis, Furier transform infrared analysis, and capillary absorption, the properties of a cement composite produced by introducing waste tyre rubber into a cement mixture were investigated. It was found that the composite filled with the rubber had a much lower water absorption ability than the unfilled one.

  6. Fracture analysis of cement treated demolition waste using a lattice model

    NARCIS (Netherlands)

    Xuan, D.; Schlangen, H.E.J.G.; Molenaar, A.A.A.; Houben, L.J.M.

    2013-01-01

    Fracture properties of cement treated demolition waste were investigated using a lattice model. In practice the investigated material is applied as a cement treated road base/subbase course. The granular aggregates used in this material were crushed recycled concrete and masonry. This results in six

  7. Studies Involving Immobilization Of Hazardous Wastes In Cement-ilmenite Matrix

    International Nuclear Information System (INIS)

    El-Dakrory, A.M.; Sayed, M.S.; Adham, K.

    1999-01-01

    Ilmenite was added to Ordinary Portland Cement to Modify the characteristic properties of the matrix as density, compressive strength and thermal stability . Coal tar and radiocesium were solidified as hazardous waste in cement-ilmenite matrix. The physical properties as density, sitting times and porosity were studied. The mechanical properties as compressive strength values and the chemical properties as leaching were measured

  8. Sulfur polymer cement stabilization of elemental mercury mixed waste

    International Nuclear Information System (INIS)

    Melamed, D.; Fuhrmann, M.; Kalb, P.; Patel, B.

    1998-04-01

    Elemental mercury, contaminated with radionuclides, is a problem throughout the Department of Energy (DOE) complex. This report describes the development and testing of a process to immobilize elemental mercury, contaminated with radionuclides, in a form that is non-dispersible, will meet EPA leaching criteria, and has low mercury vapor pressure. In this stabilization and solidification process (patent pending) elemental mercury is mixed with an excess of powdered sulfur polymer cement (SPC) and additives in a vessel and heated to ∼35 C, for several hours, until all of the mercury is converted into mercuric sulfide (HgS). Additional SPC is then added and the mixture raised to 135 C, resulting in a homogeneous molten liquid which is poured into a suitable mold where is cools and solidifies. The final stabilized and solidified waste forms were characterized by powder X-ray diffraction, as well as tested for leaching behavior and mercury vapor pressure. During this study the authors have processed the entire inventory of mixed mercury waste stored at Brookhaven National Laboratory (BNL)

  9. Influence of the waste glass in the axial compressive strength of Portland cement concrete

    International Nuclear Information System (INIS)

    Miranda Junior, E.J.P.; Paiva, A.E.M.

    2012-01-01

    In this work, was studied the influence of the incorporation of waste glass, coming from the stage of thinning and polishing of a company of thermal glass treatments, in the axial compressive strength of Portland cement concrete. The coarse and ground aggregates used was crushed stone and sand, respectively. For production of the concrete, percentages of glass residues of 5%, 10% and 20% had been used in substitution to the sand, and relations water/cement (a/c) 0,50, 0,55 and 0,58. The cure of the test bodies was carried through in 7, 14 and 28 days. The statistics analysis of the results was carried out through of the analysis of variance for each one of the cure times. From the results of the compressive strength of the concrete, it could be observed that the concrete has structural application for the relation a/c 0,5, independently of waste glass percentage used, and for the relation a/c 0,55 with 20% of waste glass. (author)

  10. Integral migration and source term experiments on cement and bitumen waste forms

    International Nuclear Information System (INIS)

    Ewart, F.T.; Howse, R.M.; Sharpe, B.M.; Smith, A.J.; Thomason, H.P.; Williams, S.J.; Young, M.

    1986-01-01

    This is the final report of a programme of research which formed a part of the CEC joint research project into radionuclide migration in the geosphere (MIRAGE). This study addressed the aspects of integral migration and source term. The integral migration experiment simulated, in the laboratory, the intrusion of water into the repository, the leaching of radionuclides from two intermediate level wasteforms and the subsequent migration through the geosphere. The simulation consisted of a source of natural ground water which flowed over a sample of wasteform, at a controlled redox potential, and then through backfill and geological material packed in columns. The two wasteforms used here were cemented waste from the WAK plant at Karlsruhe, W. Germany and bitumenised intermediate concentrates from the Marcoule plant in France. The soluble fission products such as caesium wire rapidly released from the cemented waste but the actinides, and technetium in the reduced state, were retained in the wasteform. The release of all nuclides from the bitumenised waste was very low. (author)

  11. Evaluation of sulfur polymer cement as a waste form for the immobilization of low-level radioactive or mixed waste

    International Nuclear Information System (INIS)

    Mattus, C.H.; Mattus, A.J.

    1994-03-01

    Sulfur polymer cement (SPC), also called modified sulphur cements, is a relatively new material in the waste immobilization field, although it was developed in the late seventies by the Bureau of Mines. The physical and chemical properties of SPC are interesting (e.g., development of high mechanical strength in a short time and high resistance to many corrosive environments). Because of its very low permeability and porosity, SPC is especially impervious to water, which, in turn, has led to its consideration for immobilization of hazardous or radioactive waste. Because it is a thermosetting process, the waste is encapsulated by the sulfur matrix; therefore, very little interaction occurs between the waste species and the sulfur (as there can be when waste prevents the set of portland cement-based waste forms)

  12. Characterization of Mechanical and Bactericidal Properties of Cement Mortars Containing Waste Glass Aggregate and Nanomaterials

    Directory of Open Access Journals (Sweden)

    Pawel Sikora

    2016-08-01

    Full Text Available The recycling of waste glass is a major problem for municipalities worldwide. The problem concerns especially colored waste glass which, due to its low recycling rate as result of high level of impurity, has mostly been dumped into landfills. In recent years, a new use was found for it: instead of creating waste, it can be recycled as an additive in building materials. The aim of the study was to evaluate the possibility of manufacturing sustainable and self-cleaning cement mortars with use of commercially available nanomaterials and brown soda-lime waste glass. Mechanical and bactericidal properties of cement mortars containing brown soda-lime waste glass and commercially available nanomaterials (amorphous nanosilica and cement containing nanocrystalline titanium dioxide were analyzed in terms of waste glass content and the effectiveness of nanomaterials. Quartz sand is replaced with brown waste glass at ratios of 25%, 50%, 75% and 100% by weight. Study has shown that waste glass can act as a successful replacement for sand (up to 100% to produce cement mortars while nanosilica is incorporated. Additionally, a positive effect of waste glass aggregate for bactericidal properties of cement mortars was observed.

  13. Characterization of Mechanical and Bactericidal Properties of Cement Mortars Containing Waste Glass Aggregate and Nanomaterials

    Science.gov (United States)

    Sikora, Pawel; Augustyniak, Adrian; Cendrowski, Krzysztof; Horszczaruk, Elzbieta; Rucinska, Teresa; Nawrotek, Pawel; Mijowska, Ewa

    2016-01-01

    The recycling of waste glass is a major problem for municipalities worldwide. The problem concerns especially colored waste glass which, due to its low recycling rate as result of high level of impurity, has mostly been dumped into landfills. In recent years, a new use was found for it: instead of creating waste, it can be recycled as an additive in building materials. The aim of the study was to evaluate the possibility of manufacturing sustainable and self-cleaning cement mortars with use of commercially available nanomaterials and brown soda-lime waste glass. Mechanical and bactericidal properties of cement mortars containing brown soda-lime waste glass and commercially available nanomaterials (amorphous nanosilica and cement containing nanocrystalline titanium dioxide) were analyzed in terms of waste glass content and the effectiveness of nanomaterials. Quartz sand is replaced with brown waste glass at ratios of 25%, 50%, 75% and 100% by weight. Study has shown that waste glass can act as a successful replacement for sand (up to 100%) to produce cement mortars while nanosilica is incorporated. Additionally, a positive effect of waste glass aggregate for bactericidal properties of cement mortars was observed. PMID:28773823

  14. Valorisation of waste plastic bags in cement-mortar composites as ...

    African Journals Online (AJOL)

    2015-01-07

    Jan 7, 2015 ... Keywords: Waste plastic bags, cement-plastic-mortar composite, aggregates coating ..... and closely attached to the aggregate by physical bonds and ... transformation steps, known as fusing material behaviour. In fact,.

  15. Sustainability of cement kiln co-processing of wastes in India: a pilot study.

    Science.gov (United States)

    Baidya, Rahul; Ghosh, Sadhan Kumar; Parlikar, Ulhas V

    2017-07-01

    Co-processing in cement kiln achieves effective utilization of the material and energy value present in the wastes, thereby conserving the natural resources by reducing the use of virgin material. In India, a number of multifolded initiatives have been taken that take into account the potential and volume of waste generation. This paper studies the factors which might influence the sustainability of co-processing of waste in cement kilns as a business model, considering the issues and challenges in the supply chain framework in India in view of the four canonical pillars of sustainability. A pilot study on co-processing was carried out in one of the cement plant in India to evaluate the environmental performance, economical performance, operational performance and social performance. The findings will help India and other developing countries to introduce effective supply chain management for co-processing while addressing the issues and challenges during co-processing of different waste streams in the cement kilns.

  16. Analysis by X-Ray images of wind blandes waste incorporated in Portland cement

    International Nuclear Information System (INIS)

    Marques, M.A.

    2011-01-01

    The wind blandes wastes can be reused in the incorporation in Portland cement, to be used in non-structural constructions. This work shows X-rays images to assessment the space distribution of the wastes in the cement and to evaluate the use of this methodology. Cylindrical specimens were produced according to ABNT NBR 5738 standards. The mass relation of sand, pebbles and cement was 3:2:1 and 10%, 20% and 50% of waste was incorporated in cement specimens. Frontal and upper projections were obtained in X-Rays images. The images showed that the distribution of the waste is homogeneous, consistent with what was intended in this type of incorporation, which can provide uniformity in test results of compressive strength. (author)

  17. Summary report on the development of a cement-based formula to immobilize Hanford facility waste

    International Nuclear Information System (INIS)

    Gilliam, T.M.; McDaniel, E.W.; Dole, L.R.; Friedman, H.A.; Loflin, J.A.; Mattus, A.J.; Morgan, I.L.; Tallent, O.K.; West, G.A.

    1987-09-01

    This report recommends a cement-based grout formula to immobilize Hanford Facility Waste in the Transportable Grout Facility (TGF). Supporting data confirming compliance with all TGF performance criteria are presented. 9 refs., 24 figs., 50 tabs

  18. A novel waste form for disposal of spent-nuclear-fuel reprocessing waste: A vitrifiable cement

    International Nuclear Information System (INIS)

    Gougar, M.L.D.; Scheetz, B.E.; Siemer, D.D.

    1999-01-01

    A cement capable of being hot isostatically pressed into a glass ceramic has been proposed as the waste form for spent-nuclear-fuel reprocessing wastes at the Idaho National Engineering and Environmental Laboratory (INEEL). This intermediate cement, with a composition based on that of common glasses, has been designed and tested. The cement formulations included mixed INEEL wastes, blast furnace slag, reactive silica, and INEEL soil or vermiculite, which were activated with potassium or sodium hydroxide. Following autoclave processing, the cements were characterized. X-ray diffraction analysis revealed three notable crystalline phases: quartz, calcite, and fluorite. Results of compressive strength testing ranged from 1452 and 4163 psi, exceeding the US Nuclear Regulatory Commission (NRC)-suggested standard of >500 psi. From American National Standards Institute/American Nuclear Society 16.1-1986 leach testing, effective diffusivities for Cs were determined to be on the order of 10 -11 to 10 -10 cm 2 /s and for Sr were 10 -12 cm 2 /s, which are four orders of magnitude less than diffusivities in some other radwaste materials. Average leach indices (LI) were 9.6 and 11.9 for Cs and Sr, respectively, meeting the NRC Standard of LI > 6. The 28-day Materials Characterization Center-1 leach testing resulted in normalized elemental mass losses between 0.63 and 28 g/(m 2 ·day) for Cs and between 0.34 and 0.70 g/(m 2 ·day) industry-accepted standard while Cs losses indicate a process sensitive parameter

  19. An evaluation of the composition of soil cement bricks with construction and demolition waste - doi: 10.4025/actascitechnol.v33i2.9377

    Directory of Open Access Journals (Sweden)

    Antonio Anderson da Silva Segantini

    2011-04-01

    Full Text Available Sustainable development requires the existence of a production network that includes the reuse of construction waste for new materials. Current analysis investigates an optimal soil-cement composition made up of construction and demolition waste for the manufacture of pressed bricks. Soil-cement bricks were manufactured from construction and demolition wastes (CDW, A-4 classified fine sandy soil and cement CP II Z 32. Laboratory tests, comprising test compaction, optimum water content and maximum dry specific weight, consistency limits, grain size distribution and linear shrinkage, were made to characterize the materials researched. Compressive strength and absorption tests were also undertaken in different combinations of composition. Results showed that the application of CDW improved soil-cement qualities and reduced shrinkage of the material used.

  20. Characterisation and modelling of blended cements and their application to radioactive waste immobilisation

    International Nuclear Information System (INIS)

    Glasser, F.P.; Atkins, M.; Kindness, A.

    1991-01-01

    Various aspects of the chemistry of cements, including blends with FA and BFS, pertinent to the immobilization of radioactive waste are described. The methodology and development of a model for predicting the solid and liquid phase composition in aged cement blends are given. Experimental work, backed up by thermodynamic calculations (where possible), has given valuable insight into some of the important interactions between selected (active and inactive) radwaste components and cements. The effects of elevated pressure and temperature on blended cement are also investigated. (author)

  1. Natural radioactivity of raw materials and products of cement manufacturing and of power plant fly ashes

    International Nuclear Information System (INIS)

    Gallyas, Miklos

    1984-01-01

    The natural radioactivity was investigated for several building materials used in Hungary, including cement, concrete, glasses, fine ceramic products, insulation materials, and also for some industrial wastes utilized as building material aggregates like slags, fly ashes etc., from their radiation health aspect. The dose commitments of the population from building materials standardized in several countries are presented. The 232 Th, 226 Ra, and 40 K contents of building materials were measured by gamma spectrometry, using NaI/Tl/scintillation detectors. The results were used to qualify cement materials and fly ash aggregates according to their origin in Hungary, from the point of view of their natural radioactivity. It was concluded that the radioactivity level of the majority of Hungarian cements are below the adopted international standards. (R.P.)

  2. Recycling of spent catalyst and waste sludge from industry to substitute raw materials in the preparation of Portland cement clinker

    Directory of Open Access Journals (Sweden)

    Kae-Long Lin

    2017-09-01

    Full Text Available This study investigated the feasibility of using waste limestone sludge, waste stone sludge, iron oxide sludge, and spent catalyst as raw materials in the production of eco-cement. The compressive strength development of the Eco Cement-A (ECO-A paste was similar to that of ordinary Portland cement (OPC pastes. The compressive strength development of the ECO-B paste was higher than that of OPC pastes. In addition, the C2S (Ca2SiO4, C2S and C3S (Ca3SiO5 minerals in the eco-cement paste were continuously utilized to hydrate the Ca(OH2 and calcium silicate hydrates gel (Ca6Si3O12·H2O, C–S–H throughout the curing time. When ECO-C clinker contained 8% spent catalyst, the C3S mineral content decreased and C3A (3 CaO·Al2O3 content increased, thereby causing the structure to weaken and compressive strength to decrease. The results showed that the developed eco-cement with 4% spent catalyst possessed compressive strength properties similar to those of OPC pastes.

  3. Immobilisation/solidification of hazardous toxic waste in cement matrices

    Directory of Open Access Journals (Sweden)

    Macías, A.

    1999-06-01

    Full Text Available Immobilization and solidification of polluting waste, introduced into the industrial sector more than 20 years ago, and throughout last 10 years is being the object of a growing interest for engineers and environment scientists, has become a remarkable standardized process for treatment and management of toxic and hazardous liquid wastes, with special to those containing toxic metals. Experimental monitorization of the behaviour of immobilized waste by solidification and stabilisation in life time safe deposits is not possible, reason why it is essential to develop models predicting adequately the behaviour of structures that have to undergo a range of conditions simulating the environment where they are to be exposed. Such models can be developed only if the basic physical and chemical properties of the system matrix/solidifying-waste are known. In this work immobilization/solidification systems are analyzed stressing out the formulation systems based on Portland cement. Finally, some examples of the results obtained from the study of interaction of specific species of wastes and fixation systems are presented.

    La inmovilización y solidificación de residuos contaminantes, implantada en el sector comercial desde hace más de 20 años y que desde hace diez es objeto de creciente interés por parte de ingenieros y científicos medioambientales, se ha convertido en un proceso estandarizado único para el tratamiento y gestión de residuos tóxicos y peligrosos líquidos y, en especial, de los que contienen metales pesados. La monitorización experimental del comportamiento de un residuo inmovilizado por solidificación y estabilización en el tiempo de vida de un depósito de seguridad no es posible, por lo que es imprescindible desarrollar modelos que predigan satisfactoriamente el comportamiento del sistema bajo un rango representativo de condiciones del entorno de exposición. Tales modelos sólo pueden ser desarrollados si se

  4. Influence of industrial solid waste addition on properties of soil-cement bricks

    Directory of Open Access Journals (Sweden)

    F. B. Siqueira

    Full Text Available Abstract The reuse of pollutant solid wastes produced in distinct industrial activities (avian eggshell waste and welding flux slag waste as a source of alternative raw material for producing soil-cement bricks for civil construction was investigated. Soil-cement bricks containing up to 30 wt% of industrial solid waste were uniaxially pressed and cured for 28 days. Special emphasis is given on the influence of solid waste addition on the technical properties (as such volumetric shrinkage, water absorption, bulk density, durability, and compressive strength, microstructure and mineral phases of soil-cement bricks. Microstructural evolution was evaluated via confocal microscopy. The experimental results showed that the solid wastes behave as charge material and influenced both technical properties and microstructure of the soil-cement bricks. It was found that up to 15 wt% of welding flux slag waste and up to 30 wt% of avian eggshell waste could be added into the soil-cement bricks for use as building material.

  5. Long-term modeling of glass waste in portland cement- and clay-based matrices

    International Nuclear Information System (INIS)

    Stockman, H.W.; Nagy, K.L.; Morris, C.E.

    1995-12-01

    A set of ''templates'' was developed for modeling waste glass interactions with cement-based and clay-based matrices. The templates consist of a modified thermodynamic database, and input files for the EQ3/6 reaction path code, containing embedded rate models and compositions for waste glass, cement, and several pozzolanic materials. Significant modifications were made in the thermodynamic data for Th, Pb, Ra, Ba, cement phases, and aqueous silica species. It was found that the cement-containing matrices could increase glass corrosion rates by several orders of magnitude (over matrixless or clay matrix systems), but they also offered the lowest overall solubility for Pb, Ra, Th and U. Addition of pozzolans to cement decreased calculated glass corrosion rates by up to a factor of 30. It is shown that with current modeling capabilities, the ''affinity effect'' cannot be trusted to passivate glass if nuclei are available for precipitation of secondary phases that reduce silica activity

  6. Feasibility of large volume casting cementation process for intermediate level radioactive waste

    International Nuclear Information System (INIS)

    Chen Zhuying; Chen Baisong; Zeng Jishu; Yu Chengze

    1988-01-01

    The recent tendency of radioactive waste treatment and disposal both in China and abroad is reviewed. The feasibility of the large volume casting cementation process for treating and disposing the intermediate level radioactive waste from spent fuel reprocessing plant in shallow land is assessed on the basis of the analyses of the experimental results (such as formulation study, solidified radioactive waste properties measurement ect.). It can be concluded large volume casting cementation process is a promising, safe and economic process. It is feasible to dispose the intermediate level radioactive waste from reprocessing plant it the disposal site chosen has resonable geological and geographical conditions and some additional effective protection means are taken

  7. The role of ceramics, cement and glass in the immobilization of radioactive wastes

    International Nuclear Information System (INIS)

    Glasser, F.P.

    1985-01-01

    A brief account is given of the constitution and origin of nuclear waste. The immobilization of wastes is discussed: borosilicate glasses are considered as possible matrices; ceramic forms are dealt with in more detail. The principles of the use of ceramics are explained, with examples of different ceramic structures; cements are mentioned as being suitable for wet, medium- to low-active wastes. The effects of radiation on cement, ceramic and glass waste forms are indicated. The account concludes with 'summary and future progress'. (U.K.)

  8. Hydration study of limestone blended cement in the presence of hazardous wastes containing Cr(VI)

    International Nuclear Information System (INIS)

    Trezza, M.A.; Ferraiuelo, M.F.

    2003-01-01

    Considering the increasing use of limestone cement manufacture, the present paper tends to characterize limestone behavior in the presence of Cr(VI). The research reported herein provides information regarding the effect of Cr(VI) from industrial wastes in the limestone cement hydration. The cementitious materials were ordinary Portland cement, as reference, and limestone blended cement. The hydration and physicomechanical properties of cementitious materials and the influence of chromium at an early age were studied with X-ray diffraction (XRD), infrared spectroscopy (FTIR), conductimetric and mechanical tests. Portland cement pastes with the addition of Cr(VI) were examined and leaching behavior with respect to water and acid solution were investigated. This study indicates that Cr(VI) modifies the rate and the components obtained during the cement hydration

  9. Using cement, lignite fly ash and baghouse filter waste for solidification of chromium electroplating treatment sludge

    Directory of Open Access Journals (Sweden)

    Wantawin, C.

    2004-02-01

    Full Text Available The objective of the study is to use baghouse filter waste as a binder mixed with cement and lignite fly ash to solidify sludge from chromium electroplating wastewater treatment. To save cost of solidification, reducing cement in binder and increasing sludge in the cube were focused on. Minimum percent cement in binder of 20 for solidification of chromium sludge was found when controlling lignite fly ash to baghouse filter waste at the ratio of 30:70, sludge to binder ratio of 0.5, water to mixer ratio of 0.3 and curing time of 7 days. Increase of sludge to binder ratio from 0.5 to 0.75 and 1 resulted in increase in the minimum percent cement in binder up to 30 percent in both ratios. With the minimum percent cement in binder, the calculated cement to sludge ratios for samples with sludge to binder ratios of 0.5, 0.75 and 1 were 0.4, 0.4 and 0.3 respectively. Leaching chromium and compressive strength of the samples with these ratios could achieve the solidified waste standard by the Ministry of Industry. For solidification of chromium sludge at sludge to binder ratio of 1, the lowest cost binder ratio of cement to lignite fly ash and baghouse filter waste in this study was 30:21:49. The cost of binder in this ratio was 718 baht per ton dry sludge.

  10. Effect of nano clay particles on mechanical, thermal and physical behaviours of waste-glass cement mortars

    International Nuclear Information System (INIS)

    Aly, M.; Hashmi, M.S.J.; Olabi, A.G.; Messeiry, M.; Hussain, A.I.

    2011-01-01

    Highlights: → Glass powder (GP) and nano clay (NC) were used as a partial cement replacement in cement mortar (CM). → No damaging effect can be detected due to the reaction between GP and CM with particle size up to 75 μm. → Hybrid combination of GP/NC greatly improved mechanical properties and microstructure of CM. - Abstract: Worldwide, around 2.6 billion tons of cement is produced annually. This huge size of production consumes large amounts of energy and is one of the largest contributors to carbon dioxide (CO 2 ) release. Accordingly, there is a pressing demand to minimise the quantity of cement used in the concrete industry. The main challenge to this is to get durable concrete with less cement and within reasonable cost. The economic, environmental and engineering benefits of reusing ground waste-glass powder (WGP) as a partial cement replacement has been established, but low glass reactivity and the possible alkali-silica reaction (ASR) are a drawback. Recent advances in nano-technology have revealed that nano-sized particles such as nano clay (NC) have a high surface area to volume ratio that provides the potential for tremendous chemical reactivity, accelerating pozzolanic activity and hindering ASR. This paper presents a laboratory study of the properties of NC/WGP cement composites. The microstructure, ASR, fracture energy, compressive and flexural properties of cement mortars containing WGP as a cement replacement with and without NC are investigated and compared with plain matrix. In addition, the hydration of cement compounds was followed by differential thermal analysis (DTA), thermogravimetric analysis (TGA), and also X-ray diffraction (XRD). The results showed that incorporation of glass powder has a positive effect on the mechanical properties of cement mortars after 28 days of hydration. Also, the results revealed that the mechanical properties of the cement mortars with a hybrid combination of glass powder and NC were all higher than

  11. Fiscal 1999 technical survey report. Model project implementation feasibility study in India on cement calcination facilities waste heat recovery; 1999 nendo Indo ni okeru cement shosei setsubi hainetsu kaishu model jigyo jisshi kanosei chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    India produces 96-million tons/year of cement, ranking fourth in the world, and 55% of the yield comes from 1-million tons/year plants. Some of the waste heat from the manufacturing process is used to dry materials, etc., but much is discharged into the atmosphere. Estimation is made of the energy conservation effect expected to be brought about in case the waste heat power generation technology which is in use to good effect in Japan is introduced into Indian cement plants whose clinker production exceeds 3,000 tons/day. As the result, it is concluded that the model project may be implemented at any of the four plants for which power generation capability and CO2 reduction effect are tentatively calculated below. There will be power generation of 7,300kW and CO2 reduction of 43,125 tons for the Guijarat Ambuja Cement Ltd./Ambuja Cement Eastern plant; power generation of 7,700kW and CO2 reduction of 901,960 tons for the India Cement Ltd./Rassi Cement plant; power generation of 45,098kW and CO2 reduction of 1,140,220 tons for the Larsen and Toubro Ltd./Hirmi plant; and power generation of 5,450kW and CO2 reduction of 32,230 tons for the J. K. Corp Ltd./Lakshmi Cement Sirohi plant. (NEDO)

  12. Obtaining a sulfoaluminate belite cement by industrial waste

    Directory of Open Access Journals (Sweden)

    Elkhadiri, L.

    2003-06-01

    Full Text Available Sulfoaluminate belite clinkers by burning raw at moderate temperatures near 1250 °C were synthesized. The used mixtures were made by calcium carbonate blended to two industrial wastes: low calcium fly ash and phosphogypsum. The clinkers were characterised by X-Ray Diffraction (XRD, Infrared Spectroscopy (FTIR and free lime. The hydraulic behaviour of the obtained cements, by adequate clinkers with 7% of added gypsum, was followed by XRD, scaning electronic microscopy (SEM, FTIR and NMR.

    Los clínkeres belíticos de sulfoaluminatos se obtienen por cocción de crudos a temperaturas moderadas, hacia 1.250 ºC. Esos crudos se componen de carbonato de calcio mezclados con dos subproductos industriales: cenizas volantes pobres en óxido de calcio y fosfoyeso. Los clínkeres obtenidos se caracterizaron a través de Difracción de Rayos X (DRX, Espectroscopia Infrarroja por Transformada de Fourier (FTIR y por la determinación de CaO libre. El comportamiento hidráulico de los cementos elaborados de los clínkeres con el 7% de yeso se estudió por DRX, Microscopía Electrónica de Barrido (SEM, FTIR y Resonancia Magnética Nuclear (RMN

  13. Decomposition for the analysis of radionuclides in solidified cement radioactive waste

    International Nuclear Information System (INIS)

    Lee, Jeong Jin; Pyo, Hyung Yeal; Jee, Kwang Yung; Jeon, Jong Seon

    2004-01-01

    Spent ion exchange resins make solid radioactive wastes when mixed with cement as solidifying material that was widely used in securing human environment from radionuclides for at least hundreds years. The cumulative increase of low and medium level radioactive wastes results in capacity problem of temporary storage in some NPPs (Nuclear Power Plants) of Korea around 2008. Radioactive wastes are scheduled to be disposed in a permanent disposal facility in accordance with the Korean Radioactive Wastes Management Program. It is mandatory to identify kinds and concentration of radionuclides immobilized for transporting them from temporary storage in NPPs to disposal facility. Accordingly, the effective sample decomposition prior to radiochemical separation is prerequisite to obtain the analytical data about radionuclides in cement waste forms. The closed-vessel microwave digestion technology among several sample preparation methods is taken into account to decompose cement waste forms. In this study, SRM 1880a (Portland cement) which is known for its certified values was used to optimize decomposition condition of cement waste forms containing nonradioactive ion exchange resins from NPP. With such variables as reagents, time, and power, the variation of the transparency and the color of the solution after closed-vessel microwave digestion can be examine. SRM 1880a is decomposed by suggested digestion procedure and the recoveries of constituents were investigated by ICP-AES and AAS

  14. Safety evaluation of the radioactive waste-cement composites, (4)

    International Nuclear Information System (INIS)

    Matsuzuru, Hideo; Wadachi, Yoshiki; Ito, Akihiko

    1976-10-01

    The leaching behavior of 137 Cs has been studied to evaluate safety of sea and ground disposal of the cement composites. The rate depends on flow rate of the external solution, particle radius and composition of the cement composite. The rate-determining step of the leaching in the dynamic condition is the internal diffusion through the matrix cement composite. The rate in the static condition, on the other hand is controlled by external diffusion through the interface layer between solid and liquid. The cement composites containing mineral zeolite(25%) give very low leachability; the leaching fraction is 0.001 - 0.02 for the portland cement and 0.001 - 0.002 for the slag cement. (auth.)

  15. Immobilization of radioactive waste in cement-based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, D.; McCulloch, C.E.; Angus, M.J.

    1984-01-01

    Model studies of the behaviour of cement systems have been advanced by considering the nature of the phases formed during hydration and deriving pH-composition models for the CaO-SiO 2 -H 2 O system. Preliminary results of Esub(h) measurements are also reported. Leach tests on Sr from cements are interpreted in terms of Sr retention mechanisms. Present results indicate that the aluminate phases in OPC contribute to the chemical retentivity. Studies on cement-clinoptilolite reactions, made using coarse grained clinoptilolite are reported: ferrierite also reacts chemically with cement. Two critical surveys are presented, together with new data: one on the potential of blended cements, the other on cement durability in CO 2 -containing environments. (author)

  16. Influence of natural sorbents in immobilization of radioactive waste in cement

    International Nuclear Information System (INIS)

    Plecas, I.; Dimovic, S.

    2006-01-01

    Leach characteristics of 137 Cs and 60 Co radionuclides from spent mix bead ion exchange resins and both ordinary Portland cement and cement mixed with two kind of natural sorbents, (bentonite and clinoptilolite) have been studied using International Atomic Energy's (IAEA) standard leach method. A study is undertaken to determine the waste immobilization performance of low-level wastes in cement-natural sorbents mixtures. The solidification matrix was a standard Portland cement mixed with 290-350 (kg/m 3 ) spent mix bead exchange resins, with or without 1-10 % of bentonite or/and clinoptilolite The leaching rates from the cement-bentonite matrix as 60 Co: (1.20-9.72)x10 -5 (cm/d) and for 137 Cs: (1.00-9.22)x10 -4 (cm/d), after 300 days were measured. From the leaching data the apparent diffusivity of cobalt and cesium in cement bentonite or/and clinoptilolite matrix with a waste load of 350 (kg/m 3 ) spent mix bead exchange resins was measured as 60 Co: (1.0-5.9)x10 -6 (cm 2 /d) and for 137 Cs: (0.48-2.4)x10 -4 (cm 2 /d) after 300 days. The compressive strength of these samples is determined following the ASTM standards. These results are part of a 30-year mortar and concrete testing project which will influence the design of radioactive waste management for a future Serbian radioactive waste disposal center. (author)

  17. Processing of concentrated radioactive wastes into cement and bitumens following calcination

    International Nuclear Information System (INIS)

    Napravnik, J.; Sazavsky, P.; Ditl, P.; Prikryl, P.

    1985-01-01

    A brief characteristic is presented of the most frequently used processes of solidification of liquid radioactive wastes, viz., bituminization, cementation and their combination with calcination. The effect of individual parameters is assessed on the choice of the type of solidification process as is their importance in the actual process, in temporary storage, during transportation and under conditions of long-term storage. It has been found that a combination of the procedures could lead to a modular system of methods and equipment. This would allow to approach optimal solidification of wastes in the present period and to establish a research reserve for the development of more modern, economically advantageous and safer procedures. A rough estimate is made of the costs of the solidification of 1 m 3 of radioactive concentrate from the V-1 power plant at a production of 380 m 3 /year, this for the cementation-calcination and bituminization-calcination procedures. The said rough economic analysis only serves to identify the major operating components which have the greatest effect on the economic evaluation of the solidification procedures. (Z.M.)

  18. Encapsulation of mixed radioactive and hazardous waste contaminated incinerator ash in modified sulfur cement

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Colombo, P.

    1990-01-01

    Some of the process waste streams incinerated at various Department of Energy (DOE) facilities contain traces of both low-level radioactive (LLW) and hazardous constituents, thus yielding ash residues that are classified as mixed waste. Work is currently being performed at Brookhaven National Laboratory (BNL) to develop new and innovative materials for encapsulation of DOE mixed wastes including incinerator ash. One such material under investigation is modified sulfur cement, a thermoplastic developed by the US Bureau of Mines. Monolithic waste forms containing as much as 55 wt % incinerator fly ash from Idaho national Engineering Laboratory (INEL) have been formulated with modified sulfur cement, whereas maximum waste loading for this waste in hydraulic cement is 16 wt %. Compressive strength of these waste forms exceeded 27.6 MPa. Wet chemical and solid phase waste characterization analyses performed on this fly ash revealed high concentrations of soluble metal salts including Pb and Cd, identified by the Environmental Protection Agency (EPA) as toxic metals. Leach testing of the ash according to the EPA Toxicity Characteristic Leaching Procedure (TCLP) resulted in concentrations of Pb and Cd above allowable limits. Encapsulation of INEL fly ash in modified sulfur cement with a small quantity of sodium sulfide added to enhance retention of soluble metal salts reduced TCLP leachate concentrations of Pb and Cd well below EPA concentration criteria for delisting as a toxic hazardous waste. 12 refs., 4 figs., 2 tabs

  19. Effect of blended materials on U(VI) retention characteristics for portland cement solidification product

    International Nuclear Information System (INIS)

    Tan Hongbin; Ma Xiaoling; Li Yuxiang

    2006-01-01

    Using the simulated groundwater as leaching liquid, the retention capability of U(VI) in solidification products with Portland cement, the Portland cement containing silica fume, the Portland cement containing metakaolin and the Portland cement containing fly ash was researched by leaching experiments at 25 degree C for 42 d. The results indicate silica fume and metakaolin as blended materials can improve the U(VI) retention capability of Portland cement solidification product, but fly ash can not. (authors)

  20. Characterization of different types of ceramic waste and its incorporation to the cement paste; Caracterizaco de diferentes tipos de residuos ceramicos e sua incorporacao a pasta de cimento

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, G.A.; Evangelista, A.C.J.; Almeida, V.C. de, E-mail: valeria@eq.ufrj.b [Universidade Federal do Rio de Janeiro (EQ/UFRJ), RJ (Brazil). Escola de Quimica

    2009-07-01

    The porcelain tike is a product resulting from the technological development of ceramic plating industry. Its large acceptation by the consumer market is probably linked with certain properties, such as low porosity, high mechanical resistance, facility in maintenance, besides being a material of modern and versatile characteristics. The aim of this work was characterizing the different ceramic wastes (enameled and porcelain tike) and evaluating its influence on the mechanical behavior in cement pastes. The wastes were characterized through the determination of its chemical composition, size particle distribution and X-ray diffraction. Cement pastes + wastes were prepared in 25% and 50% proportions and glue time determination, water absorption and resistance to compression assays were taken. The results indicate that although the wastes don't show any variation in the elementary chemical composition, changes in the cement paste behavior related to the values of resistance to compression were observed. (author)

  1. Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties

    Directory of Open Access Journals (Sweden)

    Moisés Frías

    2018-04-01

    Full Text Available The worldwide pursuit of new eco-efficient pozzolans is ongoing. Kaolinite-based waste is an eco-friendly source of recycled metakaolinite, a highly pozzolanic product. In this study, a blended cement paste containing 20% activated coal waste (ACW was exposed to a 100% CO2 atmosphere at 65% RH for 7 days. The variations in its phase composition and strength were studied and compared to an OPC control. Both pastes were cured for 28 days prior to the carbonation test. Reaction kinetics were assessed using XRD, SEM/EDX, TG/DTG, FT-IR, Micro-Raman spectroscopy, pore solution pH and the cumulative carbonated fraction. The blended cement carbonated 68% faster than the control. While portlandite carbonation was the main reaction in both cements, decalcification was also observed (more intensely in the 20% ACW paste in other hydraulic calcium phases (C-S-H gel, monocarboaluminate (C4AcH12, ettringite and tetracalcium aluminate (C4AH13. The end product of this reaction was calcium carbonate, mainly in the form of calcite, although traces of aragonite and amorphous carbonate were also detected. Compressive strength values rose with accelerated carbonation time and pore size reduction in both cement pastes.

  2. The effect of cure conditions on the stability of cement waste forms after immersion in water

    International Nuclear Information System (INIS)

    Siskind, B.; Adams, J.W.; Clinton, J.H.; Piciulo, P.L.; McDaniel, K.

    1988-01-01

    We investigated the effects of curing conditions on the stability of cement-solidified ion-exchange resins after immersion in water. The test specimens consisted of partially depleted mixed-bed bead resins solidified in one of three vendor-supplied Portland I cement formulations, in a reference cement formulation, or in a gypsum-based binder formulation. We cured samples prepared using each formulation in sealed containers for periods of 7, 14, or 28 days as well as in air or with an accelerated heat cure prior to 90-day immersion in water. Two cement formulations exhibited apparent Portland-cement-like behavior, i.e., compressive strength increased or stabilized with increasing cure time. Two cement formulations exhibited behavior apparently unlike that of Portland cement, i.e., compressive strength decreased with increasing cure time. Such non-Portland-cement-like behavior is correlated with higher waste loadings. The gypsum-based formulation exhibited approximately constant compressive strength with cure time. Accelerated heat cures may not give compressive strengths representative of real-time cures. Some physical deterioration (cracking, spalling) of the waste form occurs during immersion

  3. The effect of cure conditions on the stability of cement waste forms after immersion in water

    International Nuclear Information System (INIS)

    Siskind, B.; Adams, J.W.; Clinton, J.H.; Piciulo, P.L.

    1988-01-01

    The authors investigated the effects of curing conditions on the stability of cement-solidified ion-exchange resins after immersion in water. The test specimens consisted of partially depleted mixed-bed bead resins solidified in one of three vendor-supplied Portland I cement formulations, in a reference cement formulation, or in a gypsum-based binder formulation. They cured samples prepared using each formulation in sealed containers for periods of 7, 14, or 28 days as well as in air or with an accelerated heat cure prior to 90-day immersion in water. Two cement formulations exhibited apparent Portland-cement-like behavior, i.e., compressive strength increased or stabilized with increasing cure time. Two cement formulations exhibited behavior apparently unlike that of Portland cement, i.e. compressive strength decreased with increasing cure time. Such non-Portland-cement-like behavior is correlated with higher waste loadings. The gypsum-based formulation exhibited approximately constant compressive strength with cure time. Accelerated heat cures may not give compressive strengths representative of real-time cures. Some physical deterioration (cracking, spalling) of the waste form occurs during immersion

  4. Chemical stability of seven years aged cement-PET composite waste form containing radioactive borate waste simulates

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, H.M., E-mail: hosamsaleh70@yahoo.com [Radioisotope Department, Atomic Energy Authority, Dokki (Egypt); Tawfik, M.E. [Department of Polymers and Pigments, National Research Center, Dokki (Egypt); Bayoumi, T.A. [Radioisotope Department, Atomic Energy Authority, Dokki (Egypt)

    2011-04-15

    Different samples of radioactive borate waste simulate [originating from pressurized water reactors (PWR)] have been prepared and solidified after mixing with cement-water extended polyester composite (CPC). The polymer-cement composite samples were prepared from recycled poly (ethylene terephthalate) (PET) waste and cement paste (water/cement ratio of 40%). The prepared samples were left to set at room temperature (25 deg. C {+-} 5) under humid conditions. After 28 days curing time the obtained specimens were kept in their molds to age for 7 years under ambient conditions. Cement-polymer composite waste form specimens (CPCW) have been subjected to leach tests for both {sup 137}Cs and {sup 60}Co radionuclides according to the method proposed by the International Atomic Energy Agency (IAEA). Leaching tests were justified under various factors that may exist within the disposal site (e.g. type of leachant, surrounding temperature, leachant behavior, the leachant volume to CPCW surface area...). The obtained data after 260 days of leaching revealed that after 7 years of aging the candidate cement-polymer composite (CPC) containing radioactive borate waste samples are characterized by adequate chemical stability required for the long-term disposal process.

  5. INEL studies concerning solidification of low-level waste in cement

    International Nuclear Information System (INIS)

    Mandler, J.W.

    1989-01-01

    The Idaho National Engineering Laboratory (INEL) has performed numerous studies addressing issues concerning the solidification of low-level radioactive waste in cement. These studies have been performed for both the Nuclear Regulatory Commission (NRC) and the Department of Energy (DOE). This short presentation will only outline the major topics addressed in some of these studies, present a few conclusions, and identify some of the technical concerns we have. More details of the work and pertinent results will be given in the Working Group sessions. The topics that have been addressed at the INEL which are relevant to this Workshop include (1) solidification of ion-exchange resins and evaporator waste in cement at commercial nuclear power plants, (2) leachability and compressive strength of power plant waste solidified in cement, (3) suggested guidelines for preparation of a solid waste process control program (PCP), (4) cement solidification of EPICOR-II resin wastes, and (5) performance testing of cement-solidified EPICOR-II resin wastes

  6. Investigation on the potential of waste cooking oil as a grinding aid in Portland cement.

    Science.gov (United States)

    Li, Haoxin; Zhao, Jianfeng; Huang, Yuyan; Jiang, Zhengwu; Yang, Xiaojie; Yang, Zhenghong; Chen, Qing

    2016-12-15

    Although there are several methods for managing waste cooking oil (WCO), a significant result has not been achieved in China. A new method is required for safe WCO management that minimizes the environmental threat. In this context, this work was developed in which cement clinker and gypsum were interground with various WCOs, and their properties, such as grindability, water-cement ratio required to achieve a normal consistency, setting times, compressive strength, contents of calcium hydroxide and ettringite in the hardened paste, microstructure and economic and environmental considerations, were addressed in detail. The results show that, overall, WCO favorably improves cement grinding. WCO prolonged the cement setting times and resulted in longer setting times. Additionally, more remarkable effects were found in cements in which WCO contained more unsaturated fatty acid. WCOs increased the cement strength. However, this enhancement was rated with respect to the WCO contents and components. WCOs decreased the CH and AFt contents in the cement hardened paste. Even the AFt content at later ages was reduced when WCO was used. WCO also densify microstructure of the hardened cement paste. It is economically and environmentally feasible to use WCOs as grinding aids in the cement grinding process. These results contribute to the application of WCOs as grinding aids and to the safe management of WCO. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. A analysis of cementation technology for liquid radioactive-waste in PWR NPPs

    International Nuclear Information System (INIS)

    Chen Liang; Chen Li; Li Junhua

    2009-01-01

    Cementation is one of the most popular solidification technology for the low-and-intermediate level liquid radioactive waste. It has been applied in all of domestic PWR NPPs. The process characteristics and operation of the cementations in the different NPPs are introduced,and the advantage and disadvantage of the cementation are analyzed in this paper. A drum and a cask are compared as a package of the solidified waste, the drum can decrease over 50% final volume of the waste, furthermore the cost for manufacture and transportation for this drum is more cheaper than the cask, but an additional shielding may be necessary for the waste with higher level radioactivity that is packed in drum. More waste can be contained if an appropriate in-drum mixer is used while secondary waste will be unavoidable if the out-drum mixing is adopted. A carriage can make it easier to decontaminate on the surface of equipment and on the floor, furthermore the carriage is more economical than a roller conveyor in manufacture and maintenance. The cementation recipe for the waste should be optimized and additive material should be as less as possible to increase the containing rate of the waste. (authors)

  8. Evaluation of the properties of bitumen and cement pastes and mortars used in the immobilization of waste radioactive

    International Nuclear Information System (INIS)

    Vieira, Vanessa Mota; de Tello, Cledola Cassia Oliveira

    2013-01-01

    The Project RBMN was launched in November 2008 and aims to establish, manage and execute all tasks for implementing the Brazilian Repository, from its conception to its construction. The concept to be adopted will be a near-surface repository. The inventory includes wastes from the operation of nuclear power plants, fuel cycle facilities and from the use of radionuclides in medicine, industry and activities research and development. The implementation of the national repository is an important technical requirement, and a legal requirement for the entry into operation of the nuclear power plant Angra 3. In Brazil, for the immobilization and solidification of radioactive waste of low and intermediate level of radiation from NPPs are used cement, in Angra 1, and bitumen, in Angra 2. Studies indicate serious concerns about the risks associated with bituminization radioactive waste, much related to the process as the product. There are two major problems due to the presence of products bituminization in repositories, swelling of the waste products and their degradation in the long term. To accommodate the swelling, filling the drums must be limited to 70 - 90% of its volume, which reduces the structural stability of the repository and the optimization of deposition. This study aims to evaluate of the properties of bitumen and cement pastes and mortars used in the immobilization of waste radioactive. (author)

  9. Calcination of kaolinite clay particles for cement production

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse

    2014-01-01

    Kaolinite rich clay particles calcined under certain conditions can attain favorable pozzolanic properties and can be used to substitute part of the CO2 intensive clinker in cement production. To better guide calcination of a clay material, a transient one-dimensional single particle model...

  10. Geo-environmental application of municipal solid waste incinerator ash stabilized with cement

    Directory of Open Access Journals (Sweden)

    Davinder Singh

    2017-04-01

    Full Text Available The behavior of soluble salts contained in the municipal solid waste incinerator (MSWI ash significantly affects the strength development and hardening reaction when stabilized with cement. The present study focuses on the compaction and strength behavior of mixed specimens of cement and MSWI ash. A series of indices such as unconfined compressive strength, split tensile strength, California bearing ratio (CBR and pH value was examined. Prior to this, the specimens were cured for 7 d, 14 d, and 28 d. The test results depict that the maximum dry density (MDD decreases and the optimum moisture content (OMC increases with the addition of cement. The test results also reveal that the cement increases the strength of the mixed specimens. Thus, the combination of MSWI ash and cement can be used as a lightweight filling material in different structures like embankment and road construction.

  11. Engineering properties of cement mortar with pond ash in South Korea as construction materials: from waste to concrete

    Science.gov (United States)

    Jung, Sang Hwa; Kwon, Seung-Jun

    2013-09-01

    Among the wastes from coal combustion product, only fly ash is widely used for mineral mixture in concrete for its various advantages. However the other wastes including bottom ash, so called PA (pond ash) are limitedly reused for reclamation. In this paper, the engineering properties of domestic pond ash which has been used for reclamation are experimentally studied. For this, two reclamation sites (DH and TA) in South Korea are selected, and two domestic PAs are obtained. Cement mortar with two different w/c (water to cement) ratios and 3 different replacement ratios (0%, 30%, and 60%) of sand are prepared for the tests. For workability and physical properties of PA cement mortar, several tests like flow, setting time, and compressive strength are evaluated. Several durability tests including porosity measuring, freezing and thawing, chloride migration, and accelerated carbonation are also performed. Through the tests, PA (especially from DH area) in surface saturated condition is evaluated to have internal curing action which leads to reasonable strength development and durability performances. The results show a potential applicability of PA to concrete aggregate, which can reduce consuming natural resources and lead to active reutilization of coal product waste.

  12. Immobilization of radioactive waste in cement-based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, D.; Angus, M.J.; Atkins, M.; Dept. of Chemistry)

    1985-01-01

    A solubility model of the system CaO-SiO 2 -H 2 O is developed which takes account of the state of Si polymerization in the solid. Free energies of formations of its bonding hydrogel are tabulated. The internal redox conditions in cements have been measured; in particular, slags lower the Esub(eta) relative to OPC. The fate of Sr and U in cement systems has been determined; Sr is incorporated in the aluminate phases, while U 6+ is precipitated as Ca-U-O-H 2 O phases. Lowering the internal Esub(eta) reduces U solubility. Studies of the carbonation of slag-cement blends are reported. (author)

  13. The use of cement grouts for the immobilisation of solid radioactive waste

    International Nuclear Information System (INIS)

    Brown, D.J.; Smith, D.L.

    1982-06-01

    The use of cement grouts is being considered for the immobilisation of solid items of radioactive waste. In this report the factors which influence the selection of a grout for use in an active plant are identified. The properties and limitations of standard cement grouts are summarised. Inactive grouting trials carried out in the period September 1981 to June 1982 on the 220 dm 3 scale are described. (author)

  14. The incorporation of low and medium level radioactive wastes (solids and liquids) in cement

    International Nuclear Information System (INIS)

    Brown, D.J.; Capp, P.D.; Smith, D.L.

    1982-08-01

    Laboratory studies and mixing plant trials on simulated radioactive waste formulations are reported. Long term stability testing of various formulations including those containing blast furnace slag-ordinary Portland cement, sodium nitrate, ion exchange resins, and sodium nitrate-tributyl phosphate, are reported and some results are given. Mixing plant trials with a high shear cement mixer are reported. An outline of future work is presented. (U.K.)

  15. Research, Calculation for Designing the Technological Equipment Line of Cementation with 3,000 Tonnes of Solid Waste/Year Capacity for ZOC Plan

    International Nuclear Information System (INIS)

    Tran Van Hoa; Ngo Van Tuyen; Nguyen Ba Tien; Le Ba Thuan; Phung Quoc Khanh; Mai Duc Lanh; Vuong Huu Anh; Luu Cao Nguyen; Duong Dinh Tho; Phung Vu Phong; Nguyen An Thai; Pham Quang Minh

    2013-01-01

    Technological process and equipment line for cementation with 3,000 tons of solid wastes/year capacity for ZOC plant was studied according to the quantity, the composition and the property of solid wastes from ZOC plant. The influence of several parameters with cementation process such as cement mixing ratio, size, moisture and NaCl content in residue, which affected to mechanical and chemical strength of waste block after cementation was evaluated. The calculation and designing for cementation equipment line were thus conducted and total investment cost of construction and installation as well as operation of this equipment line was also estimated. Radiation safety and environmental protection for waste treatment facility was calculated and the design on radiation safety and environmental protection for equipment line was proposed. Technological process and design document of this production line seemed to be reasonable because it is consistent with properties of wastes as well as it has been commonly used in the world to stabilize solid residues in nuclear industry. The advantages of this propose were simple structure of the devices, locally made, easy operation, locally available and inexpensive materials resulting in low cost of investment and operation. (author)

  16. Immobilization of radioactive waste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Macphee, D.; Atkins, M.; Beckley, N.; Carson, S.; McHugh, G.; Mattingley, N.J.; Naish, C.C.; Wilding, C.R.

    1988-01-01

    The modelling of cement behaviour at longer ages is reported. Factors studied include composition, pH and Esub(h). The stresses arising from irradiation are evaluated. The behaviour of two elements in cement - U and I has been studied; new experimental data are reported including solubility measurements. Some additional data are given on Sr. Results of desk studies relevant to lifetime predictions are presented. (author)

  17. Sulfur polymer cement, a solidification and stabilization agent for radioactive and hazardous wastes

    International Nuclear Information System (INIS)

    Darnell, R.G.

    1993-01-01

    Sulfur polymer cement (SPC) is made by reacting 95% sulfur with 2.5 % dicyclopentadiene and 2.5% cyclopentadiene oligomers, to produce a product that is much better than unmodified sulfur. SPC is being tested as a solidifying and stabilizing agent for low-level radioactive and hazardous wastes. Heavy loadings (5 wt%) of eight toxic metals were combined individually with SPC and 7 wt% sodium sulfide nonahydrate. The leach rates for mercury, lead, chromium and silver oxides were reduced by six orders of magnitude, while those of arsenic and barium were reduced by four. SPC is good for stabilizing incinerator ash. Ion-exchange resins can be stabilized with SPC after heat treatment with asbestos or diatomite at 220-250 deg C. 19 refs

  18. Comparison of bitumen and cement immobilization of intermediate- and low-level radioactive waste

    International Nuclear Information System (INIS)

    Voss, J.W.

    1979-01-01

    This paper discusses a systems comparison of two available immobilization processes for intermediate- and low-level radioactive wastes -- bitumen and cement. This study examines a conceptual coprocessed UO 2 - PuO 2 fuel cycle. Radioactive wastes are generated at each stage of this fuel cycle. This study focuses on these transuranic (TRU) wastes generated at a conceptual Fuel Coprocessing Facility. In this report, these wastes are quantified, the immobilization systems conceptualized to process these wastes are presented, and a comparison of the systems is made

  19. The Immobilisation of Krom and Stronsium Waste Using Natural Fiber Reinforced Cement

    International Nuclear Information System (INIS)

    Susetyo Haria Putero; Nunung Prabaningrum; Widya Rosita

    2007-01-01

    Cementation of hazardous liquid waste is one of the methods to minimize its detrimental effect on the environmental quality and human health. This research purpose was to study the effect of natural fiber composition and temperature on quality of the cement block reinforced by coconut (Cocos nucifera) fiber and bamboo (Bambusa vulgaris) fiber. This research was pursued by adsorbing stronsium waste and krom using zeolite. Thirteen percent volume of zeolite was mixed with 0.3 of water/cement ratio. Composition of natural fiber was varied by 0.00v/o, 0.05v/o, 0.10v/o, 0.25v/o, 0.50v/o, 0.75v/o and 1.00v/o. The cement blocks produced were heated at 0℃, 50℃, 100℃, 150℃, 200℃ and 250℃ for 10 minutes and then determined their compressive strength and leaching rate. The optimum composition of natural fiber causing increasing of mechanical strength has been founded at 0.50% v/o of fiber. On that composition the axial force resistance of fiber is higher than the radial one. The hydration reaction completely works when cement block is heated until certain temperature that results in the increasing of its compressive strength. However, the compressive strength of cement block heated up to 250℃ is still beyond the standard. Based on its compressive strength, the bamboo (Bambusa vulgaris) fiber is more feasible than coconut (Cocos nucifera) fiber for reinforcing cement block. Heating just influences on the physics properties of cement block. But, the ability of block cement to immobilize a matter is affected by properties of matters. (author)

  20. Contribution to the study of wastes stabilization by sulfo-aluminate cement

    International Nuclear Information System (INIS)

    Peysson, S.

    2005-02-01

    Calcium sulfo-aluminate cement is mainly composed of yeelimite known to be a precursor of ettringite formation. Ettringite is able to incorporate several heavy metals by isomorphous substitutions without altering its crystalline structure. The design of a binder required for immobilizing heavy metals was undertaken. The hydration study of clinker, and cement containing 4 amounts of gypsum has been carried out by means of XRD, DTA and IR spectrometry. It was pointed out that the addition of gypsum enhances hydration. Two binders were selected: 80/20 and 70/30. The immobilisation of 7 pollutants was very successful. Nevertheless, damages appeared with the binder 70/30 containing sodium chromate and dichromate: sodium caused activation of yeelimite reactivity and important dissolution of gypsum leading to important ettringite production. With a great amount of gypsum (30 %), dissolution led to secondary ettringite formation which damaged the hardened paste. Adding polyol enhances the retention of sodium chromate. On the other hand, the immobilisation of two types of weakly radioactive wastes supplied by CEA has been made. Results obtained in terms of setting time, compressive strength and leaching were excellent. (author)

  1. Review of technologies for mercury removal from flue gas from cement production processes

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Anker Degn; Windelin, Christian

    2012-01-01

    sources of mercury in the cement kiln flue gas. Cement plants are quite different from power plants and waste incinerators regarding the flue gas composition, temperature, residence time, and material circulation. Cement kiln systems have some inherent ability to retain mercury in the solid materials due...... to the adsorption of mercury on the solids in the cold zone. However, recirculation of the kiln dust to the kiln will cause release of the captured mercury. The mercury chemistry in cement kiln systems is complicated and knowledge obtained from power plants and incinerators cannot be directly applied in cement...

  2. Review of palm oil fuel ash and ceramic waste in the production of concrete

    Science.gov (United States)

    Natasya Mazenan, Puteri; Sheikh Khalid, Faisal; Shahidan, Shahiron; Shamsuddin, Shamrul-mar

    2017-11-01

    High demand for cement in the concrete production has been increased which become the problems in the industry. Thus, this problem will increase the production cost of construction material and the demand for affordable houses. Moreover, the production of Portland cement leads to the release of a significant amount of CO2 and other gases leading to the effect on global warming. The need for a sustainable and green construction building material is required in the construction industry. Hence, this paper presents utilization of palm oil fuel ash and ceramic waste as partial cement replacement in the production of concrete. Using both of this waste in the concrete production would benefit in many ways. It is able to save cost and energy other than protecting the environment. In short, 20% usage of palm oil fuel ash and 30% replacement of ceramic waste as cement replacement show the acceptable and satisfactory strength of concrete.

  3. Corrosion studies on mild steel in contact with cemented waste forms

    International Nuclear Information System (INIS)

    Platts, N.

    1987-03-01

    The internal corrosion of mild steel drums has been assessed in support of the proposed cementation of low level solid and sludge wastes arising from the Winfrith SGHWR. General corrosion rates are expected to be very low but while oxygen is present pitting, at least in principle, is possible. Passive currents for mild steel in contact with the different cement formulations have therefore been determined, thereby enabling the timescale for residual oxygen within the drums to be assessed. These measurements indicate that for BFS/OPC cement formulations the oxygen will be exhausted within 37 days, though potential monitoring suggests that sulphides present in the cement may reduce this figure. For PFA/OPC cement formulations the passive currents suggest that it would take ca. one year for the oxygen present in a drum to be exhausted. Therefore though pitting should not be a problem with the BFS/OPC cement formulations, further investigation of the extent of pitting that may occur in the PFA/OPC waste form is desirable. (author)

  4. Immobilization of radioactive waste in cement based matrices

    International Nuclear Information System (INIS)

    Glasser, F.P.; Rahman, A.A.; Macphee, D.; Atkins, M.; Beckley, N.; Lachowski, E.E.

    1986-04-01

    A mathematical and thermodynamic model of the Ca0-Si0 2 -H 2 0 system is presented to enable the solubility and pH relationships in cement and blended cement systems to be predicted. The Esub(h) function has been explored particularly in respect of slag rich systems. The stability of Sr in cements is shown to be influenced by both precipitation and lattice incorporation into the ettringite-like phase. Quality assurance parameters especially for aggregate materials and blast furnace slags are reviewed and recommendations made. It is shown that the latter fluctuate considerably in composition; additional measures for monitoring are recommended and additional research suggested to determine their long-term performance. (author)

  5. Microbially influenced degradation of cement-solidified low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Rogers, R.D.; Hamilton, M.A.; Veeh, R.H.; McConnell, J.W. Jr.

    1996-01-01

    Because of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. This paper contains information on three groups of microoganisms that are associated with the degradation of cement materials: sulfur-oxidizing bacteria (Thiobacillus), nitrifying bacteria (Nitrosomonas and Nitrobacter), and heterotrophic bacteria, which produce organic acids. Preliminary work using laboratory- and vendor-manufactured, simulated waste forms exposed to thiobacilli has shown that microbiologically influenced degradation has the potential to severely compromise the structural integrity of ion-exchange resin and evaporator-bottoms waste that is solidified with cement. In addition, it was found that a significant percentage of calcium was leached from the treated waste forms. Also, the surface pH of the treated specimens was decreased to below 2. These conditions apparently contributed to the physical deterioration of simulated waste forms after 30 to 60 days of exposure

  6. Characterizing cemented TRU waste for RCRA hazardous constituents

    International Nuclear Information System (INIS)

    Yeamans, D.R.; Betts, S.E.; Bodenstein, S.A.

    1996-01-01

    Los Alamos National Laboratory (LANL) has characterized drums of solidified transuranic (TRU) waste from four major waste streams. The data will help the State of New Mexico determine whether or not to issue a no-migration variance of the Waste Isolation Pilot Plant (WIPP) so that WIPP can receive and dispose of waste. The need to characterize TRU waste stored at LANL is driven by two additional factors: (1) the LANL RCRA Waste Analysis Plan for EPA compliant safe storage of hazardous waste; (2) the WIPP Waste Acceptance Criteria (WAC) The LANL characterization program includes headspace gas analysis, radioassay and radiography for all drums and solids sampling on a random selection of drums from each waste stream. Data are presented showing that the only identified non-metal RCRA hazardous component of the waste is methanol

  7. Implementation of radon measurements to evaluate the suitability of using cement containers for storing radioactive waste containing Ra-226

    International Nuclear Information System (INIS)

    Shweikani, R.; Kheituo, M.; Hushari, M.; Ali, A. F.

    2003-12-01

    This work aimed at studying radon diffusion through walls of cubic cement containers containing inside radioactive waste rich in Radium-226. In addition, the effect of the wall thickness on radon exhalation and external gamma exposure were also studded. Cubic cement molds were prepared with different dimensions ranged from 5 to 11 cm containing central cubic holes to contain the radioactive materials with dimensions ranged from 2 to 7 cm. The thicknesses of the walls were varied from 1 to 4 cm. Radon exhalation was studied by placing each pre-prepared cement specimen in a tightly closed glass container (desiccators, volume 7 liters) provided with input and output gas system circulation for one week. Active method (Lucas cell) was used to measure the concentration of radon in the container. It was noticed that radon concentration increased with the increase of the radioactive materials inside the specimens. This was simply explained as it is due to the increase of the amount of radium-226 in the specimen with will definitely lead to the increase of radon production. In addition, it was noticed that radon concentration were increased by increasing the thickness of the specimen wall for fixed amount of the radioactive materials inside. This result was unexpected. Therefore, many attempts were performed to explain it. For that, the mechanism of cement solidifications and structure of cement after solidification were studied. The conditions which affect the size and number of the formed pores in the specimens were also studied assuming that increasing the wall thickness will increase porosity and lead to the increase diffusion paths. It was concluded that it is possible to use the cubic cement containers to stop gamma radiation from the radioactive materials, but it is not possible to use them to stop radon unless special arrangements are performed. (author)

  8. Assessment of geotechnical properties of uncemented/cemented clayey soil incorporated with waste crumb rubber

    Directory of Open Access Journals (Sweden)

    JITENDRA SINGH YADAV

    2017-03-01

    Full Text Available Discarded waste tires are becoming a serious threat to health, environment, and ecological systems worldwide if it is not disposed of properly. Every year 1000 million of waste tires are discarded. This number may grow up to 1200 million by the year 2030. On the other hand, construction of civil engineering structures such as buildings, dams, highways, etc. are at high risk of differential settlement, especially in the case of weak or soft clay, which is due to its low shear strength and high compressibility. The paper aims to assess geotechnical properties of uncemented/cemented clayey soil incorporated with waste crumb rubber. Compaction parameters, unconfined compressive strength, split tensile strength, toughness index, CBR values and swelling pressure of rubberized uncemented/cemented clayey soil (3%, and 6% cement and different percentage of crumb rubber have been obtained. After rigorous extensive study, it has been concluded that unconfined compressive strength and split tensile strength of rubberized cemented clayey soil decreases with the increase of the percentage of crumb rubber whereas the axial, and diametral strain are found to be increased with the addition of crumb rubber up to 5% after that it starts to decrease. The CBR values, swelling pressure, and toughness index of uncemented/cemented clayey soil was significantly affected by incorporation of crumb rubber. SEM studies have also been incorporated in this investigation.

  9. Results of the freeze resistance test, swelling index and coefficient of permeability of finegrained mining waste reinforced with cements

    Science.gov (United States)

    Morman, Justyna

    2018-04-01

    The article presents the result of laboratory tests for mining waste with grain size of 0 to 2 mm stabilized with cement. Used for stabilization of cement CEM I 42.5 R and blast furnace cement CEM III / A 42.5N - LH / HSR / NA and a plasticizer sealant. Cement was added to the mining waste test in the proportions of 5 - 8% in relation to the skeleton's weight. For the cemented samples, the freeze resistance test, swelling index, coefficient of permeability and pH of water leachate were tested. The addition of a cement binder resulted in diminishing the water permeability of mining waste and limiting the leaching of fine particles from the material.

  10. Leachability characteristics of beryllium in redmud waste and its stabilization in cement

    International Nuclear Information System (INIS)

    Saradhi, I.V.; Mahadevan, T.N.; Krishnamoorthy, T.M.

    1999-01-01

    More than 70% of the beryl ore processed by the Beryllium Metal Plant at the BARC Vashi Complex ends up as redmud waste. The presence of significant quantities (0.4 to 0.8%) of beryllium in the redmud qualifies it as hazardous requiring safe handling, storage and disposal. The waste also contains 0.09% of water soluble fluoride. The various standard protocol of procedures were employed to estimate the leachability of beryllium from redmud for both short term and long term periods. Nearly 50% of beryllium present in redmud is leachable in water. We have tried the stabilization of redmud using portland cement. The proportion of redmud to cement was in the ratio of 1:1, 1:2 and 1:4. The blocks were cast, cured and used in the leachability experiments using standard protocols as above. The results of the TCLP test gave the levels of beryllium well below the standard limits in the TCLP extract of cement stabilized waste indicating the suitability of stabilization of redmud with cement whereas that of raw waste (redmud) are much higher than the prescribed limits. The total leach percent of beryllium in 1:2 block is 0.05% over period of 164 days whereas 1:1 and 1:4 gave a leach percent of 0.26 and 0.15% respectively. The DLT results indicate, diffusion controlled release of beryllium from the cement stabilized redmud blocks. The effective diffusion coefficient of beryllium obtained from the modelling study is 10 orders of magnitude less than the molecular diffusion coefficient of beryllium indicating the effectiveness of cement stabilization. From the detailed experiments performed, it is felt that 1:2 proportion of redmud and cement will be the best suited option for stabilization of redmud waste. The 1:1 proportion of redmud to cement mixture which could not be cast into compact cement blocks also exhibited very low leachability characteristics similar to 1:2 and 1:4 and can be be favourably considered for stabilization in case of space constraints at storage sites. The

  11. Characterization, Improvement and Long Term Evaluation Of Cementitious Waste Products. An Indian Scenario

    International Nuclear Information System (INIS)

    Yaeotikar, R.G.; Rakesh, R.R.; Shirole, A.; Paul, B.; Valsala, T.P.; Choudhury, D.K.

    2013-01-01

    Cement is a very good matrix for immobilization for different types of wastes. In India, the cementation process has been adopted and used for the last four decades. Depending on the waste composition, there is need to formulate the cement waste matrix appropriately to ensure adequate compressive strength and chemical durability. This has been achieved by using different additives/backfill materials during the cementation process with cements for example Ordinary Portland Cement (OPC) and Slag Based Cements (SBC). Backfill materials studied include vermiculite and bentonite. They were evaluated for sorption characteristics, particle size distribution, water equilibration, etc. They were incorporated in the OPC-CWP (Cement Waste Product) with various waste compositions. The composition developed for ILW generated during reprocessing and during spent solvent hydrolysis were successfully adopted on a plant scale. Some of the compositions which are being developed are also in the process of being adopted in-plant. The long-term evaluation study of the CWP was carried out at actual site conditions where CWP in carbon steel drum, plastic drums and bare CWP were disposed in 2001 and removed in 2010: parameters including compressive strength and release of activity to the soil were measured. (author)

  12. Preliminary assessment of nine waste-form products/processes for immobilizing transuranic wastes

    International Nuclear Information System (INIS)

    Crisler, L.R.

    1980-09-01

    Nine waste-form processes for reduction of the present and projected Transuranic (TRU) waste inventory to an immobilized product have been evaluated. Product formulations, selected properties, preparation methods, technology status, problem areas needing resolution and location of current research development being pursued in the United States are discussed for each process. No definitive utility ranking is attempted due to the early stage of product/process development for TRU waste containing products and the uncertainties in the state of current knowledge of TRU waste feed compositional and quantitative makeup. Of the nine waste form products/processes included in this discussion, bitumen and cements (encapsulation agents) demonstrate the degree of flexibility necessary to immobilize the wide composition range present in the TRU waste inventory. A demonstrated process called Slagging Pyrolysis Incineration converts a varied compositional feed (municipal wastes) to a ''basalt'' like product. This process/product appears to have potential for TRU waste immobilization. The remaining waste forms (borosilicate glass, high-silica glass, glass ceramics, ''SYNROC B'' and cermets) have potential for immobilizing a smaller fraction of the TRU waste inventory than the above discussed waste forms

  13. Utilization of steel slag for Portland cement clinker production.

    Science.gov (United States)

    Tsakiridis, P E; Papadimitriou, G D; Tsivilis, S; Koroneos, C

    2008-04-01

    The aim of the present research work is to investigate the possibility of adding steel slag, a by-product of the conversion of iron to steel process, in the raw meal for the production of Portland cement clinker. Two samples of raw meals were prepared, one with ordinary raw materials, as a reference sample ((PC)(Ref)), and another with 10.5% steel slag ((PC)(S/S)). Both raw meals were sintered at 1450 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the steel slag did not affect the mineralogical characteristics of the so produced Portland cement clinker. Furthermore, both clinkers were tested by determining the grindability, setting times, compressive strengths and soundness. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of the steel slag did not negatively affect the quality of the produced cement.

  14. Red mud addition in the raw meal for the production of Portland cement clinker.

    Science.gov (United States)

    Tsakiridis, P E; Agatzini-Leonardou, S; Oustadakis, P

    2004-12-10

    The aim of the present research work was to investigate the possibility of adding red mud, an alkaline leaching waste, which is obtained from bauxite during the Bayer process for alumina production, in the raw meal for the production of Portland cement clinker. For that reason, two samples of raw meals were prepared: one with ordinary raw materials, as a reference sample ((PC)Ref), and another with 3.5% red mud ((PC)R/M). The effect on the reactivity of the raw mix was evaluated on the basis of the unreacted lime content in samples sintered at 1350, 1400 and 1450 degrees C. Subsequently, the clinkers were produced by sintering the two raw meals at 1450 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the red mud did not affect the mineralogical characteristics of the so produced Portland cement clinker. Furthermore, both clinkers were tested by determining the grindability, setting time, compressive strength and expansibility. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of the red mud did not negatively affect the quality of the produced cement.

  15. Solidification of Waste Steel Foudry Dust with Portland Cement

    Czech Academy of Sciences Publication Activity Database

    Škvára, F.; Kaštánek, František; Pavelková, I.; Šolcová, Olga; Maléterová, Ywetta; Schneider, Petr

    B89, č. 1 (2001), s. 67-81 ISSN 0304-3894 R&D Projects: GA ČR GA104/99/0440 Institutional research plan: CEZ:AV0Z4072921; CEZ:MSM 223100002 Keywords : solidification, * foundry dust * cement Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.497, year: 2001

  16. Factors affecting the leachability of caesium and strontium from cemented simulant evaporator wastes

    International Nuclear Information System (INIS)

    Lee, D.J.; Brown, D.J.

    1981-08-01

    Leach rates of stable cesium and strontium from a range of simulated evaporator waste/cement formulations have been determined. Important factors in plant operation are assessed for their effect on leach rates. Increasing the curing time and lowering the water/cement ratio has been shown to reduce leach rates by up to a factor of four. Incorporation of additives such as clays and supplementary cementatious materials can reduce leach rates by up to three orders magnitude, and coating the surface of the waste form with a neat cement grout can reduce the cesium leach rate by up to four orders of magnitude. The effects of permeability of the matrix and its cesium absorption capacity on the leach rates have been analysed qualitatively. (U.K.)

  17. Solidification process for toxic and hazardous wastes. Second part: Cement solidification matrices

    International Nuclear Information System (INIS)

    Donato, A.; Arcuri, L.; Dotti, M.; Pace, A.; Pietrelli, L.; Ricci, G.; Basta, M.; Cali, V.; Pagliai, V.

    1989-05-01

    This paper reports the second part of a general study carried out at the Nuclear Fuel Division aiming at verifying the possible application of the radioactive waste solidification processes to industrial hazardous wastes (RTN). The cement solidification of several RTN types has been taken into consideration, both from the technical and from the economic point of view. After a short examination of the Italian juridical and economical situation in the field, which demonstrates the need of the RTN solidification, the origin and characteristics of the RTN considered in the study and directly provided by the producing industries are reviewed. The laboratory experimental results of the cementation of RTN produced by gold manufacturing industries and by galvanic industries are reported. The cementation process can be considered a very effective mean for reducing both the RTN management costs and the environmental impact of RTN disposal. (author)

  18. Leachability of bentonite/cement for medium-level waste immobilisation

    Energy Technology Data Exchange (ETDEWEB)

    Hamlat, M.S.; Rabia, N. [Centre de Radioprotection et de Surete, Alger-Gare (Algeria)

    1998-12-31

    The release of radionuclides from Algerian bentonite/cement matrix has been measured experimentally using static and dynamic testing procedures. The waste forms were cement/sand and bentonite/cement matrices contaminated with Cs-137. To characterise radionuclide/waste form combination, two parameters, diffusion (D) and distribution coefficients ({alpha}) were used. (D) is an effective diffusion coefficient that describes the kinetic behaviour and is most easily determined using Soxhlet test, whereas, ({alpha}) describes the distribution of radionuclide between aqueous and solid phases at equilibrium and is best measured in static test. Leach rates obtained being very low. Distribution coefficient values have showed that the bentonite has relatively a high degree of fixation. It was concluded that the matrix under study seems play a role for the immobilisation. (orig.)

  19. Leachability of bentonite/cement for medium-level waste immobilisation

    International Nuclear Information System (INIS)

    Hamlat, M.S.; Rabia, N.

    1998-01-01

    The release of radionuclides from Algerian bentonite/cement matrix has been measured experimentally using static and dynamic testing procedures. The waste forms were cement/sand and bentonite/cement matrices contaminated with Cs-137. To characterise radionuclide/waste form combination, two parameters, diffusion (D) and distribution coefficients (α) were used. (D) is an effective diffusion coefficient that describes the kinetic behaviour and is most easily determined using Soxhlet test, whereas, (α) describes the distribution of radionuclide between aqueous and solid phases at equilibrium and is best measured in static test. Leach rates obtained being very low. Distribution coefficient values have showed that the bentonite has relatively a high degree of fixation. It was concluded that the matrix under study seems play a role for the immobilisation. (orig.)

  20. Partial replacement of Portland cement by red ceramic waste in mortars: study of pozzolanic activity

    International Nuclear Information System (INIS)

    Silva, A.R. da; Cabral, K.C.; Pinto, E.N. de M.G.l.

    2016-01-01

    The objective of this study is to analyze the pozzolanic activity of red ceramic residue on the partial replacement of Portland cement in mortars. The mortars were prepared by substituting 25% of the Portland cement for ground of ceramic residue with water cement’s factor of 0.48. The concrete used to construct the reference mortars and those with addiction was CPII-Z-32 (compound of Portland pozzolana cement). The chemical analysis and physical ceramic waste showed that this meets the requirements of NBR12653 (2014) for use as pozzolanic material. The pozzolanic activity index (IAP) obtained for the ceramic waste to twenty-eight days cure rate was 80.28%. (author)

  1. Sulfur polymer cement, a new stabilization agent for mixed and low- level radioactive waste

    International Nuclear Information System (INIS)

    Darnell, G.R.

    1991-01-01

    Solidification and stabilization agents for radioactive, hazardous, and mixed wastes are failing to pass governmental tests at alarming rates. The Department of Energy's National Low-Level Waste Management Program funded testing of Sulfur Polymer Cement (SPC) by Brookhaven National Laboratory during the 1980s. Those tests and tests by the US Bureau of Mines (the original developer of SPC), universities, states, and the concrete industry have shown SPC to be superior to hydraulic cements in most cases. Superior in what wastes can be successfully combined and in the quantity of waste that can be combined and still pass the tests established by the US Environmental Protection Agency and the US Nuclear Regulatory Commission

  2. Performance Characteristics of Waste Glass Powder Substituting Portland Cement in Mortar Mixtures

    Science.gov (United States)

    Kara, P.; Csetényi, L. J.; Borosnyói, A.

    2016-04-01

    In the present work, soda-lime glass cullet (flint, amber, green) and special glass cullet (soda-alkaline earth-silicate glass coming from low pressure mercury-discharge lamp cullet and incandescent light bulb borosilicate glass waste cullet) were ground into fine powders in a laboratory planetary ball mill for 30 minutes. CEM I 42.5N Portland cement was applied in mortar mixtures, substituted with waste glass powder at levels of 20% and 30%. Characterisation and testing of waste glass powders included fineness by laser diffraction particle size analysis, specific surface area by nitrogen adsorption technique, particle density by pycnometry and chemical analysis by X-ray fluorescence spectrophotometry. Compressive strength, early age shrinkage cracking and drying shrinkage tests, heat of hydration of mortars, temperature of hydration, X-ray diffraction analysis and volume stability tests were performed to observe the influence of waste glass powder substitution for Portland cement on physical and engineering properties of mortar mixtures.

  3. The cement recycling of the earthquake disaster debris by Hachinohe Cement Co., Ltd

    International Nuclear Information System (INIS)

    Kataoka, Masayuki

    2015-01-01

    A tremendous quantity of earthquake disaster debris and tsunami sediment was resulted by the Great East Japan Earthquake on March 11, 2011. Hachinohe Cement Co., Ltd., a Sumitomo Osaka Cement subsidiary, was the first cement industry company to receive and process such waste materials outside of their usual prefecture area, while the company is performing their treatment and recycling services locally in Hachinohe City and Aomori Prefecture. This report provides an explanation about the recycling mechanism of waste materials and by-products in cement manufacturing process, and introduces an example of actual achievements for the disaster debris treatment by utilizing the cement recycling technologies at the Hachinohe Cement Plant. (author)

  4. Optimization and validation of a chemical process for uranium, mercury and cesium leaching from cemented radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Reynier, N.; Lastra, R.; Laviolette, C.; Bouzoubaa, N., E-mail: nicolas.reynier@canada.ca [Natural Resources Canada, CanmetMINING, Ottawa, Ontario (Canada); Chapman, M. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2015-12-15

    Canadian Nuclear Laboratories (CNL) is developing a treatment and long-term management strategy for a legacy cemented radioactive waste that contains uranium, mercury, and fission products. Extracting the uranium would be advantageous for decreasing the waste classification and reducing the cost of long-term management. The chemical leachability of 3 key elements (U, Hg, and Cs) from a surrogate cemented waste (SCW) was studied with several lixiviants. The results showed that the most promising approach to leach and recover U, Hg, and Cs is the direct leaching of the SCW with H{sub 2}SO{sub 4} in strong saline media. Operating parameters such as particle size, temperature, pulp density, leaching time, acid and salt concentrations, number of leaching/washing steps, etc. were optimized to improve key elements solubilization. Sulfuric leaching in saline media of a SCW (U5) containing 1182 ppm of U, 1598 ppm of Hg, and 7.9 ppm of Cs in the optimized conditions allows key elements solubilisation of 98.5 ± 0.4%, 96.6 ± 0.1%, and 93.8 ± 1.1% of U, Hg, and Cs, respectively. This solubilization process was then applied in triplicate to 7 other SCWs prepared with different cements, liquid ratios, and at different aging times and temperatures. Concentrated sulfuric acid is added to the slurry until the pH is about 2, which causes the complete degradation of cement and the formation of CaSO{sub 4}. Sulfuric acid is particularly useful because it produces a leachate that is amenable to conventional ion exchange technology for the separation and recovery of uranium. (author)

  5. 40 CFR 63.1204 - What are the standards for hazardous waste burning cement kilns that are effective until...

    Science.gov (United States)

    2010-07-01

    ... Principal Organic Hazardous Constituents (POHCs) in the waste feed that you specify under paragraph (c)(3... in the hazardous waste feed, considering the results of hazardous waste analyses or other data and... waste burning cement kilns that are effective until compliance with the standards under § 63.1220? 63...

  6. Alkali activated slag cements using waste glass as alternative activators. Rheological behaviour

    Directory of Open Access Journals (Sweden)

    Manuel Torres-Carrasco

    2015-03-01

    The findings show that AAS paste behaviour of rheology when the activator was a commercial waterglass solution or NaOH/Na2CO3 with waste glass was similar, fit the Herschel-Bulkley model. The formation of primary C-S-H gel in both cases were confirmed. However, the rheological behaviour in standard cements fit the Bingham model. The use of the waste glass may be feasible from a rheological point of view in pastes can be used.

  7. Systematic approach for the design of pumpable cement-based grouts for immobilization of hazardous wastes

    International Nuclear Information System (INIS)

    Sams, T.L.; Gilliam, T.M.

    1987-01-01

    Cement-based grouts have been proven to be an economical and environmentally acceptable means of waste disposal. Costs can be reduced if the grout is pumped to the disposal site. This paper presents a systematic approach to guide the development of pumpable grouts. 20 refs., 2 figs

  8. Mixture optimization of cement treated demolition waste with recycled masonry and concrete

    NARCIS (Netherlands)

    Xuan, D.X.; Houben, L.J.M.; Molenaar, A.A.A.; Shui, Z.H,

    2011-01-01

    Due to environmental reasons and the shortage of natural resources, it is greatly valuable to recycle construction and demolition waste (CDW) as much as possible. One of effective ways to reuse more CDW is to produce a cemented road base material. The recycled CDW however is a mix of recycled

  9. Investigation of combined effect of mixture variables on mechanical properties of cement treated demolition waste

    NARCIS (Netherlands)

    Xuan, D.; Houben, L.J.M.; Molenaar, A.A.A.; Shui, Z.

    2012-01-01

    One of high efficient ways to reuse the recycled construction and demolition waste (CDW) is to consider it as a road base material. The recycled CDW however is mainly a mix of recycled masonry and concrete with a wide variation in composition. This results that the mechanical properties of cement

  10. Energetic and exergetic analysis of waste heat recovery systems in the cement industry

    International Nuclear Information System (INIS)

    Karellas, S.; Leontaritis, A.-D.; Panousis, G.; Bellos, E.; Kakaras, E.

    2013-01-01

    In a typical cement producing procedure, 25% of the total energy used is electricity and 75% is thermal energy. However, the process is characterized by significant heat losses mainly by the flue gases and the ambient air stream used for cooling down the clinker (about 35%–40% of the process heat loss). Approximately 26% of the heat input to the system is lost due to dust, clinker discharge, radiation and convection losses from the kiln and the preheaters. A heat recovery system could be used to increase the efficiency of the cement plant and thus contribute to emissions decrease. The aim of this paper is to examine and compare energetically and exergetically, two different WHR (waste heat recovery) methods: a water-steam Rankine cycle, and an Organic Rankine Cycle (ORC). A parametric study proved that the water steam technology is more efficient than ORC in exhaust gases temperature higher than 310 °C. Finally a brief economic assessment of the most efficient solution was implemented. WHR installations in cement industry can contribute significantly in the reduction of the electrical consumptions operating cost thus being a very attractive investment with a payback period up to 5 years. - Highlights: • This paper presents waste heat recovery as a way to gain energy from the exhaust gases in a cement plant. • Water steam cycle and ORC has been analyzed for waste heat recovery. • The energetic and exergetic evaluation of the two waste heat recovery processes is presented and compared

  11. NOx from cement production - reduction by primary measures

    DEFF Research Database (Denmark)

    Jensen, Lars Skaarup

    1999-01-01

    cement production processes cement is typically produced by thermally treating a mixture of limestone and clay minerals in kiln systems consisting of a rotary kiln and a calciner. Clinker burning at a temperature of about 1450 °C takes place in the internally fired rotary kiln and calcination, which...... rotary kilns, while NOx formation from fuel-N and reduction of NOx take place in calciners. NOx formation in the rotary kiln is mainly governed by the necessary clinker burning temperature and is not very amenable to control, while net NOx formation in calciners depends strongly on calciner design......, calciner operation, fuel properties and on the NOx level from the rotary kiln. The low-NOx calciner types presently marketed are based on combinations of reburning, air staging and temperature control and seem equivalent in their ability to restrict NOx formation. If fuels with a significant volatile...

  12. The immobilisation of shredded waste in a cement matrix

    International Nuclear Information System (INIS)

    James, J.M.; Smith, D.L.

    1985-10-01

    Progress on the preparations for the encapsulation of plutonium contaminated shredded waste is summarised. Waste drums have been modified and filled with active shredded waste. Commissioning of the grout infilling test rig was started at the end of this period. Inactive process trials have continued in support of the design of the active encapsulation plant. (author)

  13. Corrosion susceptibility of steel drums containing cemented intermediate level nuclear wastes

    Science.gov (United States)

    Duffó, Gustavo S.; Farina, Silvia B.; Schulz, Fátima M.; Marotta, Francesca

    2010-10-01

    Cementation processes are used as immobilization techniques for low or intermediate level radioactive waste for economical and safety reasons and for being a simple operation. In particular, ion-exchange resins commonly used for purification of radioactive liquid waste from nuclear reactors are immobilized before being stored to improve the leach resistance of the waste matrix and to maintain mechanical stability. Combustible solid radioactive waste can be incinerated and the resulting ashes can also be immobilized before storage. The immobilized resins and ashes are then contained in steel drums that may undergo corrosion depending on the presence of certain contaminants. The work described in this paper was aimed at evaluating the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins and incineration ashes containing different concentrations of aggressive species (mostly chloride and sulphate ions). A special type of specimen was designed to simulate the cemented waste in the drum. The evolution of the corrosion potential and the corrosion current density of the steel, as well as the electrical resistivity of the matrix were monitored over a time period of 1 year. The results show the deleterious effect of chloride on the expected lifespan of the waste containers.

  14. Corrosion susceptibility of steel drums containing cemented intermediate level nuclear wastes

    International Nuclear Information System (INIS)

    Duffo, Gustavo S.; Farina, Silvia B.; Schulz, Fatima M.; Marotta, Francesca

    2010-01-01

    Cementation processes are used as immobilization techniques for low or intermediate level radioactive waste for economical and safety reasons and for being a simple operation. In particular, ion-exchange resins commonly used for purification of radioactive liquid waste from nuclear reactors are immobilized before being stored to improve the leach resistance of the waste matrix and to maintain mechanical stability. Combustible solid radioactive waste can be incinerated and the resulting ashes can also be immobilized before storage. The immobilized resins and ashes are then contained in steel drums that may undergo corrosion depending on the presence of certain contaminants. The work described in this paper was aimed at evaluating the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins and incineration ashes containing different concentrations of aggressive species (mostly chloride and sulphate ions). A special type of specimen was designed to simulate the cemented waste in the drum. The evolution of the corrosion potential and the corrosion current density of the steel, as well as the electrical resistivity of the matrix were monitored over a time period of 1 year. The results show the deleterious effect of chloride on the expected lifespan of the waste containers.

  15. Environmental impact of incineration of calorific industrial waste: rotary kiln vs. cement kiln.

    Science.gov (United States)

    Vermeulen, Isabel; Van Caneghem, Jo; Block, Chantal; Dewulf, Wim; Vandecasteele, Carlo

    2012-10-01

    Rotary kiln incinerators and cement kilns are two energy intensive processes, requiring high temperatures that can be obtained by the combustion of fossil fuel. In both processes, fossil fuel is often substituted by high or medium calorific waste to avoid resource depletion and to save costs. Two types of industrial calorific waste streams are considered: automotive shredder residue (ASR) and meat and bone meal (MBM). These waste streams are of current high interest: ASR must be diverted from landfill, while MBM can no longer be used for cattle feeding. The environmental impact of the incineration of these waste streams is assessed and compared for both a rotary kiln and a cement kiln. For this purpose, data from an extensive emission inventory is applied for assessing the environmental impact using two different modeling approaches: one focusing on the impact of the relevant flows to and from the process and its subsystems, the other describing the change of environmental impact in response to these physical flows. Both ways of assessing emphasize different aspects of the considered processes. Attention is paid to assumptions in the methodology that can influence the outcome and conclusions of the assessment. It is concluded that for the incineration of calorific wastes, rotary kilns are generally preferred. Nevertheless, cement kilns show opportunities in improving their environmental impact when substituting their currently used fuels by more clean calorific waste streams, if this improvement is not at the expense of the actual environmental impact. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Industrial Wastes as Auxiliary Additives to Cement/Lime Stabilization of Soils

    Directory of Open Access Journals (Sweden)

    Jijo James

    2016-01-01

    Full Text Available Chemical stabilization involves the use of chemical agents for initiating reactions within the soil for modification of its geotechnical properties. Cement and lime stabilization have been the most common stabilization methods adopted for soil treatment. Cement stabilization results in good compressive strengths and is preferred for cohesionless to moderately cohesive soil but loses effectiveness when the soil is highly plastic. Lime stabilization is the most preferred method for plastic clays; however, it proves to be ineffective in sulphate rich clays and performs poorly under extreme conditions. With such drawbacks, lots of researches have been undertaken to address the issues faced with each stabilization method, in particular, the use of solid wastes for soil stabilization. Solid waste reuse has gained high momentum for achieving sustainable waste management in recent times. Research has shown that the use of solid wastes as additives with and replacement for conventional stabilizers has resulted in better results than the performance of either individually. This review provides insight into some of the works done by earlier researchers on lime/cement stabilization with industrial wastes as additives and helps to form a sound platform for further research on industrial wastes as additives to conventional stabilizers.

  17. Immobilization of low and intermediate level of organic radioactive wastes in cement matrices

    Energy Technology Data Exchange (ETDEWEB)

    Eskander, S.B. [Radioisotopes Department, Atomic Energy Authority, Dokki, Cairo (Egypt); Abdel Aziz, S.M. [Middle Eastern Regional Radioisotope Centre for the Arab Countries, Dokki, Cairo (Egypt); El-Didamony, H. [Faculty of Science, Zagazig University, Zagazig, El-Sharkia (Egypt); Sayed, M.I., E-mail: mois_161272@yahoo.com [Middle Eastern Regional Radioisotope Centre for the Arab Countries, Dokki, Cairo (Egypt)

    2011-06-15

    Highlights: {yields} Solidification/stabilization of liquid scintillation waste. {yields} Resistance to frost attack. {yields} Retarding effect of scintillator waste was overcome by adding clay. {yields} Evaluation of the suitability of cement-clay composite to solidify and stabilize scintillation waste. - Abstract: The adequacy of cement-clay composite, for solidification/stabilization of organic radioactive spent liquid scintillator wastes and its resistance to frost attack were determined by a freezing/thawing (F/T) test. Frost resistance is assessed for the candidate cement-clay composite after 75 cycles of freezing and thawing by evaluating their mass durability index, compressive strength, apparent porosity, volume of open pores, water absorption, and bulk density. Infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM) were performed for the final waste form (FWF) before and after the F/T treatment to follow the changes that may take place in its microstructure during the hydration regime. The results were obtained indicate that the candidate composite exhibits acceptable resistance to freeze/thaw treatment and has adequate suitability to solidify and stabilize organic radioactive spent liquid scintillator wastes even at very exaggerating conditions (-50{sup Degree-Sign }C and +60{sup Degree-Sign }C ).

  18. The role of cement to be expected in radioactive waste disposal system

    International Nuclear Information System (INIS)

    Tanaka, Satoru; Nagasaki, Shinya; Ohe, Toshiaki

    1997-01-01

    Based on the present states of cement in radioactive waste disposal system, its roles and functions to be further expected were discussed diming at safety evaluation of wastes. In the present waste disposal system, cement has two important roles as the structural materials for the system and as the barrier materials for protecting from various radiations. In order to enhance the durability of those materials, it is needed to improve them in respects of acid resistance and repression of the reactions with radioactive wastes. Generally development of cracks in concrete structures is inevitable and the repairs become necessary in old structures. Therefore, it is desirable that cement for a disposal system has self-diagnostic and self-repairing abilities to keep the efficiency for a long period. The compressive strength of ordinary high-strength concrete is around 50-60 Nmm -2 . However, it is needed to further increase the strength to decrease the amount of hardening materials and the width of concrete vessel for wastes. In addition, it is desirable to develop new techniques to recycle concrete wastes involving radioactive materials at ultra-low levels. (M.N.)

  19. Immobilization of low and intermediate level of organic radioactive wastes in cement matrices

    International Nuclear Information System (INIS)

    Eskander, S.B.; Abdel Aziz, S.M.; El-Didamony, H.; Sayed, M.I.

    2011-01-01

    Highlights: → Solidification/stabilization of liquid scintillation waste. → Resistance to frost attack. → Retarding effect of scintillator waste was overcome by adding clay. → Evaluation of the suitability of cement-clay composite to solidify and stabilize scintillation waste. - Abstract: The adequacy of cement-clay composite, for solidification/stabilization of organic radioactive spent liquid scintillator wastes and its resistance to frost attack were determined by a freezing/thawing (F/T) test. Frost resistance is assessed for the candidate cement-clay composite after 75 cycles of freezing and thawing by evaluating their mass durability index, compressive strength, apparent porosity, volume of open pores, water absorption, and bulk density. Infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM) were performed for the final waste form (FWF) before and after the F/T treatment to follow the changes that may take place in its microstructure during the hydration regime. The results were obtained indicate that the candidate composite exhibits acceptable resistance to freeze/thaw treatment and has adequate suitability to solidify and stabilize organic radioactive spent liquid scintillator wastes even at very exaggerating conditions (-50 ° C and +60 ° C ).

  20. Possibility of using waste tire rubber and fly ash with Portland cement as construction materials.

    Science.gov (United States)

    Yilmaz, Arin; Degirmenci, Nurhayat

    2009-05-01

    The growing amount of waste rubber produced from used tires has resulted in an environmental problem. Recycling waste tires has been widely studied for the last 20 years in applications such as asphalt pavement, waterproofing systems and membrane liners. The aim of this study is to evaluate the feasibility of utilizing fly ash and rubber waste with Portland cement as a composite material for masonry applications. Class C fly ash and waste automobile tires in three different sizes were used with Portland cement. Compressive and flexural strength, dry unit weight and water absorption tests were performed on the composite specimens containing waste tire rubber. The compressive strength decreased by increasing the rubber content while increased by increasing the fly ash content for all curing periods. This trend is slightly influenced by particle size. For flexural strength, the specimens with waste tire rubber showed higher values than the control mix probably due to the effect of rubber fibers. The dry unit weight of all specimens decreased with increasing rubber content, which can be explained by the low specific gravity of rubber particles. Water absorption decreased slightly with the increase in rubber particles size. These composite materials containing 10% Portland cement, 70% and 60% fly ash and 20% and 30% tire rubber particles have sufficient strength for masonry applications.

  1. Physical, chemical and radioactive characterization of co-products from titanium dioxide industry for valorization in the cement industry

    International Nuclear Information System (INIS)

    Gazquez, M.J.; Mantero, J.; Bolivar, J.P.; Garcia-Tenorio, R.; Vaca, F.

    2011-01-01

    The present study was conducted to characterize the raw materials (ilmenite and slag), waste (red gypsum) and several co-products (sulphate monohydrate and sulphate heptahydrated) form the titanium dioxide industry in relation to their elemental composition (major, minor and trace elements), granulometry, mineralogy, microscopic morphology, physical composition and radioactive content in order to apply this knowledge in the valorization of the co-products in the fields such a as construction, civil engineering, etc. In particular, the main properties of cements produced with different proportions of red gypsum were studied, and the obtained improvements, in relation to Ordinary Portland Cements (OPC) were evaluated. It was also demonstrated that the levels of pollutants and the radioactive content in the produced RG cements, remain within the regulated safety limits. (Author). 38 refs.

  2. Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance

    Science.gov (United States)

    Chen, Irvin Allen

    Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate

  3. Performance of aged cement - polymer composite immobilizing borate waste simulates during flooding scenarios

    International Nuclear Information System (INIS)

    Eskander, S.B.; Bayoumi, T.A.; Saleh, H.M.

    2012-01-01

    An advanced composite of cement and water extended polyester based on the recycled Poly(ethylene terephthalate) waste was developed to incorporate the borate waste. Previous studies have reported the characterizations of the waste composite (cement-polymer composite immobilizing borate waste simulates) after 28 days of curing time. The current work studied the performance of waste composite aged for seven years and subjected to flooding scenario during 260 days using three types of water. The state of waste composite was assessed at the end of each definite interval of the water infiltration through visual examination and mechanical measurement. Scanning electron microscopy, infrared spectroscopy, X-ray diffraction and thermal analyses were used to investigate the changes that may occur in the microstructure of the waste composite under aging and flooding effects. The actual experimental results indicated reasonable evidence for the waste composite. Acceptable consistency was confirmed for the waste composite even after aging seven years and exposure to flooding scenario for 260 days.

  4. Use of the “red gypsum” industrial waste as substitute of natural gypsum for commercial cements manufacturing

    Directory of Open Access Journals (Sweden)

    Gázquez, M. J.

    2012-06-01

    Full Text Available The main objective of this research has been the valorisation of a waste from the TiO2 production process (sulphate method, called red gypsum, in the production of cements. This waste is mainly formed by di-hydrate calcium sulphate and iron hydroxides. To cover this objective it has been necessary to perform the physico-chemical characterisation of the red gypsum as well as the main components in the production of cements and of the new cements generated. Moreover, for the red gypsum, has been analyzed its radioactive content because it is generated in a NORM (Naturally Occurring Radioactive Materials industry. Finally, the most important properties of the obtained cements with different proportions of red gypsum in their composition have been studied by comparing them with the standard ones obtained in a Portland cement. Lastly, we have demonstrated that the new cements fulfil all the quality tests imposed by the European legislation.

    El objetivo de esta investigación ha sido analizar la valorización de un residuo generado en el proceso de producción de dióxido de titanio (vía sulfato, denominado yeso rojo, en la producción de cementos. Dicho residuo está compuesto fundamentalmente por sulfato de calcio di-hidratado e hidróxidos de hierro. Para ello, ha sido necesaria la caracterización físico-química del yeso rojo, así como la de los otros componentes fundamentales en la fabricación de cementos y de los cementos generados con el mencionado residuo. Además, en el caso del yeso rojo, se ha analizado su contenido radiactivo al generarse éste en una industria NORM (Natural Occurring Radioactive Materials. Posteriormente, se han estudiado las propiedades más importantes de los cementos producidos con diferentes porcentajes de yeso rojo añadido, comparando estas mezclas con las propiedades de un cemento Portland comercial, comprobándose que se cumplen todas las normas Europeas de calidad exigibles.

  5. Evaluation of red mud as pozzolanic material in replacement of cement for production of mortars

    International Nuclear Information System (INIS)

    Manfroi, E.P.; Cheriaf, M.; Rocha, J.C.

    2010-01-01

    Red mud is a by-product of the alkaline extraction of aluminum from the bauxite and represents a renewed environmental problem due the significant annual throughput by the plants. In the present work, the pozzolanic properties of Brazilian red mud fired at 600, 700, 800 and 900 deg C were investigated by monitoring lime consumption using DTA analysis and Brazilian standard methodology NBR 5772 (1992). Products and kinetics of hydration were determined in cement pastes produced with 5 and 15% red mud using x-ray diffraction and DTA analysis. Compressive strength and capillary absorption tests were realized on mortars constituted by 5, 10 and 15% red mud in replacement of cement. When calcined at 600 deg C, the red mud develops good pozzolanic properties, and the compressive strength of mortars produced with this waste meet values in accordance with regulatory standard. These results shown than red mud can be used, in partial replacement of cement, as new construction material to produce sustainable mortars with low environmental impact. (author)

  6. Optimization and characterization of cement products incorporating ashes from radwaste incineration

    International Nuclear Information System (INIS)

    Donato, A.; Pace, A.; Ricci, G.

    1989-01-01

    The incineration is presently condidered a very good way to obtain strong volume reduction of intermediate and low activity solid radwastes obtaining at the same time a product apparently easy to be conditioned. In some cases nevertheless the ash solidification by cementation can give in the practice some problems. In this work the optimization of the cementation of two ash types named Nust 1 and Nust 2 has been studied. The Nust 1 ash come from the incineration of the exhausted ion exchange resins already conditioned in urea-formaldehyde. The Nust 2 ash comes from the incineration of the same materials as the Nust 1 mixed with ordinary nuclear power plant solid radwastes. Both ashes have been produced from wastes stored at the Caorso (Italy) Nuclear Power Plant. The two ash types have been characterized by a series of physico-chemical analysis whose results are reported as well as the results of the preliminary tests performed on the products obtained from their cementation

  7. Utilization of Baggase Waste Based Materials as Improvement for Thermal Insulation of Cement Brick

    Directory of Open Access Journals (Sweden)

    Aminudin Eeydzah

    2017-01-01

    Full Text Available Building materials having low thermal load and low thermal conductivity will provide thermal comforts to the occupants in building. In an effort to reduce the use of high energy and waste products from the agricultural industry, sugarcane bagasse and banana bagasse has been utilize as an additive in the manufacture of cement brick. The aim of this study is to investigate the insulation and mechanical properties of brick that has been mixed with bagasse and its effectiveness as thermal insulation using heat flow meter. Waste bagasse is being treated using sodium hydroxide (NaOH and is characterized using SEM and XRF. The samples produced with two different dimensions of 50 mm × 50 mm × 50 mm and 215mm × 102.5mm × 65mm for thermal conductivity test. Next, the sample varies from 0% (control sample, 2%, 4%, 6%, 8% and 10% in order to determine the best mix proportion. The compressive strength is being tested for 7, 14 and 28 days of water curing. Results showed that banana bagasse has lower thermal conductivity compared to sugarcane bagasse used, with compressive strength of 15.6MPa with thermal conductivity 0.6W/m.K.

  8. Effect of borate concentration on solidification of radioactive wastes by different cements

    International Nuclear Information System (INIS)

    Sun Qina; Li Junfeng; Wang Jianlong

    2011-01-01

    Highlights: → The effect of borate on cementation of radioactive borate evaporator concentrates by sulfoaluminate cement (SAC) and Portland cement (PC) was compared. → The X-ray diffraction (XRD) revealed that borate did not interfere with the formation of main hydration products of SAC and PC. → Borate, in the form of B(OH) 4- , incorporated in ettringite as solid solution phase. - Abstract: To investigate the effect of borate on the cementation of radioactive evaporator concentrates, and to provide more data for solidification formula optimization, the simulated borate evaporator concentrates with different borate concentrations (as B) and Na/B ratio (molar ratio) were solidified by sulfoaluminate cement (SAC) and Portland cement (PC), with addition of Ca(OH) 2 , zeolite and accelerator or water reducer. The hydration products of solidified matrices were characterized by X-ray diffraction (XRD). The experimental results showed that borate retarded the cement setting for both SAC and PC formulas, and the final setting time prolonged with decrease of Na/B ratio. Borate could enhance the fluidity of the cement mixture. The 28 d compressive strengths of the solidified matrices for both SAC and PC formulas decreased with increase of borate concentration. The XRD patterns suggested that, in the matrices maintained for 28 d, borate did not interfere with the formation of main hydration products of SAC and PC. Borate, in the form of B(OH) 4- , incorporated in ettringite (3CaO.Al 2 O 3 .3CaSO 4 .32H 2 O) as solid solution phase. The formula of SAC and PC developed in this study was effective for cementation of the simulated borate evaporator concentrates. However further optimization was required to reduce retarding effect of higher borate concentrations and to extend the practical feasibility for actual evaporator concentrates.

  9. AVLIS production plant waste management plan

    International Nuclear Information System (INIS)

    1984-01-01

    Following the executive summary, this document contains the following: (1) waste management facilities design objectives; (2) AVLIS production plant wastes; (3) waste management design criteria; (4) waste management plan description; and (5) waste management plan implementation. 17 figures, 18 tables

  10. FY 2000 report on the plan to carry out a model project for recovery of waste heat from the cement sintering equipment in India and the survey of the feasibility; 2000 nendo Indo ni okeru cement shosei setsubi hainetsu kaishu model jigyo jisshi keikaku oyobi fukyu kanosei chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    For the purpose of conserving energy and reducing greenhouse effect gas emission, survey was conducted on a project for recovering waste heat from the cement production process and using it for power generation in India. In India, the production amount of cement has steadily been increasing in and after the complete liberalization of the cement industry in 1989, and now the production amount is second in the world. Duties of approximately 25% are imposed on the import of the cement waste heat equipment, which is still a high-rate tariff. The India Cement Co., which is a candidate local company for this project, is a typical cement company in an excellent financial state in India. As to the economical efficiency of the project, economical effects are very good as seen in the internal earning rate of more than 30% and the period of ROI of less than 4 years, even if high-rate duties of India are imposed. There seems to be a great possibility of the spread of the related technology in the light of the following reasons: the situation of electric power in India is not good, reduction in production cost is being urgently requested due to the drop in cement price, and the equipment in this project is clean equipment using waste heat and therefore meets with the policy of the Indian government in which emphasis is placed on the environment. (NEDO)

  11. Permeability of Consolidated Incinerator Facility Wastes Stabilized with Portland Cement

    International Nuclear Information System (INIS)

    Walker, B.W.

    1999-01-01

    The Consolidated Incinerator Facility (CIF) at the Savannah River Site (SRS) burns low-level radioactive wastes and mixed wastes as method of treatment and volume reduction. The CIF generates secondary waste, which consists of ash and off-gas scrubber solution. Currently the ash is stabilized/solidified in the Ashcrete process. The scrubber solution (blowdown) is sent to the SRS Effluent Treatment Facility (ETF) for treatment as waste water. In the past, the scrubber solution was also stabilized/solidified in the Ashcrete process as blowcrete and will continue to be treated this way for listed waste burns and scrubber solution that do not meet the Effluent Treatment Facility (ETF) Waste Acceptance Criteria (WAC)

  12. Deterioration study of a material for encapsulation of radioactive wastes, the Portland cement, by heterotrophic microorganisms isolated from natural media

    International Nuclear Information System (INIS)

    Perfettini, J.

    1989-01-01

    Soils and geologic formations selected for storage of radioactive waste storage contain microflora (nitrifying and sulfoxidizing bacteria, heterotrophic microorganisms) that can corrode cement through acidic metabolism products. Nutriments required for their development are also found in these biotopes. Corrosine effects of organic acids produced by heterotrophic microorganisms are: mass decrease, leaching (especially Ca), dissolution of portlandite crystals Ca (OH) 2 , increase of porosity and decrease of flexural strength. Excretion of corrosive organic acids by bacteria is promoted by high temperature and basic pH. Acidification by fungi requires also a high temperature but an acidic pH [fr

  13. Cement encapsulation of low-level waste liquids. Final report

    International Nuclear Information System (INIS)

    Baker, M.N.; Houston, H.M.

    1999-01-01

    Pretreatment of liquid high-level radioactive waste at the West Valley Demonstration Project (WVDP) was essential to ensuring the success of high-level waste (HLW) vitrification. By chemically separating the HLW from liquid waste, it was possible to achieve a significant reduction in the volume of HLW to be vitrified. In addition, pretreatment made it possible to remove sulfates, which posed several processing problems, from the HLW before vitrification took place

  14. Optimization and validation of a chemical process for uranium, mercury and cesium leaching from cemented radioactive wastes

    International Nuclear Information System (INIS)

    Reynier, N.; Riveros, P.; Lastra, R.; Laviolette, C.; Bouzoubaa, N.; Chapman, M.

    2015-01-01

    Atomic Energy of Canada Limited (AECL) is developing a treatment and long-term management strategy for a legacy cemented radioactive waste that contains uranium, mercury and fission products. Extracting the uranium would be advantageous for decreasing the waste classification and reducing the cost of long-term management. Consequently, there are safety and economic and environmental incentives for the extraction of uranium, mercury and cesium before subjecting the cemented waste to a stabilization process. The mineralogical analysis of the surrogate cemented waste (SCW) indicated that uranium forms calcium uranate, CaUO 4 , occurring as layers of several millimeters or as grains of 20 μm. Hg is found mostly as large (∼50 μm) and small grains (5-8 μm) of HgO. The chemical leachability of three key elements (U, Hg, and Cs) from a SCW was studied with several leaching materials. The results showed that the most promising approach to leach and recover U, Hg, and Cs is the direct leaching of the SCW with H 2 SO 4 in strong saline media. Operating parameters such as particle size, temperature, pulp density, leaching time, acid and salt concentrations, number of leaching/rinsing step, etc. were optimized to improve key elements solubilization. Sulfuric leaching in saline media of a SCW (U5) containing 1182 ppm of U, 1598 ppm of Hg, and 7.9 ppm of Cs in the optimized conditions allows key elements recovery of 98.5 ± 0.4%, 96.6 ± 0.1%, and 93.8 ± 1.1% of U, Hg, and Cs respectively. This solubilization process was then applied in triplicate to seven other SCW prepared with different cement, liquid ratio and at different aging time and temperature. Concentrated sulfuric acid is added to the slurry until the pH is about 2, which causes the complete degradation of cement and the formation of CaSO 4 . At this pH, the acid consumption is moderate and the formation of amorphous silica gel is avoided. Sulfuric acid is particularly useful because it produces a leachate that

  15. Pore size distribution, strength, and microstructure of portland cement paste containing metal hydroxide waste

    Energy Technology Data Exchange (ETDEWEB)

    Majid, Z.A.; Mahmud, H.; Shaaban, M.G.

    1996-12-31

    Stabilization/solidification of hazardous wastes is used to convert hazardous metal hydroxide waste sludge into a solid mass with better handling properties. This study investigated the pore size development of ordinary portland cement pastes containing metal hydroxide waste sludge and rice husk ash using mercury intrusion porosimetry. The effects of acre and the addition of rice husk ash on pore size development and strength were studied. It was found that the pore structures of mixes changed significantly with curing acre. The pore size shifted from 1,204 to 324 {angstrom} for 3-day old cement paste, and from 956 to 263 {angstrom} for a 7-day old sample. A reduction in pore size distribution for different curing ages was also observed in the other mixtures. From this limited study, no conclusion could be made as to any correlation between strength development and porosity. 10 refs., 6 figs., 3 tabs.

  16. Detection of free liquid in cement-solidified radioactive waste drums using computed tomography

    International Nuclear Information System (INIS)

    Steude, J.S.; Tonner, P.D.

    1991-01-01

    Acceptance criteria for disposal of radioactive waste drums require that the cement-solidified material in the drum contain minimal free liquid after the cement has hardened. Free liquid is to be avoided because it may corrode the drum, escape and cause environmental contamination. The DOE has requested that a nondestructive evaluation method be developed to detect free liquid in quantities in excess of 0.5% by volume. This corresponds to about 1 liter in a standard 208 liter (55 gallon) drum. In this study, the detection of volumes of free liquid in a 57 cm (2 ft.) diameter cement-solidified drum is demonstrated using high-energy X-ray computed tomography (CT0. In this paper it is shown that liquid concentrations of simulated radioactive waste inside glass tubes imbedded in cement can easily be detected, even for tubes with inner diameters less than 2 mm (0.08 in.). Furthermore, it is demonstrated that tubes containing water and liquid concentrations of simulated radioactive waste can be distinguished from tubes of the same size containing air. The CT images were obtained at a rate of about 6 minutes per slice on a commercially available CT system using a 9 MeV linear accelerator source

  17. The Influence of Temperature on Kaolinite Fired Clay- Cement Materials Used as Disposal of Radioactive Waste

    International Nuclear Information System (INIS)

    El-Dakroury, A.

    2008-01-01

    The decay of encapsulated radioactive nuclides may cause elevation of the temperature in the waste form. Cement has been used for immobilization of low and intermediated level radioactive waste. The unstable component of concrete is the ordinary Portland cement (OPC). This study aimed to investigate experimentally the change occurring in the compressive strength and physico- chemical properties of ordinary Portland cement (OPC) matrices in comparable with other matrices which (OPC) were partially substituted by 0, 10, 20 and 30% of thermally-activated kaolinite clay by weight (the kaolinite clay activated by firing at 750 degree C for 5 hr then quenched by tap water). If all matrices mentioned before, are being exposed to the treatment temperature were varied from 100 degree C to 600 degree C by increment of 100 degree C for period of 3 hr without any load. The phase composition was performed by mean of differential thermal analysis and X-R-D. The results show that the replacements of (OPC) by 20 wt % thermal-activated Kaolinite clay improve the compressive properties by 30 %. The results of this investigation cleared that the recrystallization and carbonation of Ca(OH) 2 ; they also show a deformation of C-H-S and C 4 Ah 13 phases, besides the matrices have more stable resistance at 600 degree C. Meanwhile, this new immobilization matrix 20 % by wt thermally activated Kaolinite - clay showed the lowest leaching rate of simulated radioactive waste of Sr or Cs compared to the ordinary Portland cement (OPC) matrix

  18. Industrial Wastes as Alternative Mineral Addition in Portland Cement and as Aggregate in Coating Mortars

    OpenAIRE

    Oliveira, Kamilla Almeida; Nazário, Bruna Inácio; Oliveira, Antonio Pedro Novaes de; Hotza, Dachamir; Raupp-Pereira, Fabiano

    2017-01-01

    This paper presents an evaluation study of wastes from pulp and paper as well as construction and demolition industries for application in cement-based materials. The alternative raw materials were used as a source of calcium carbonate (CaCO3) and as pozzolanic material (water-reactive SiO2) in partial replacement of Portland cement. In addition to the hydraulic binder, coating mortars were composed by combining the pulp and paper fluidized bed sand residue with construction and demolition wa...

  19. Estimation of americium in cemented waste block using gamma ray spectrometry

    International Nuclear Information System (INIS)

    Singh, Sarbjit; Mhatre, Amol; Sagar, Veena

    2012-05-01

    A method was developed for the estimation of 241 Am present in the cemented waste block which was cylindrical in shape. In such large sample, the attenuation of gamma rays increases with size of the sample and density of the material present. Attenuation correction was incorporated using linear attenuation coefficients of 59.54 keV gamma ray of 241 Am. Also in such large samples, error due to the distribution of activity is more. Estimation of 241 Am in the cemented sample was carried out by applying corrections for attenuation and for the sample geometry. (author)

  20. The role of cement to be expected in radioactive waste disposal system. 2. From the standpoint of materials design

    International Nuclear Information System (INIS)

    Tanaka, Satoru; Nagasaki, Shinya; Ohe, Toshiaki

    2000-01-01

    Cement materials are used at various fields because of their mechanical properties, and then a large construction without using the cement materials is impossible to suppose. For disposal of radioactive wastes, it is expected to use the cement materials for a main constitution material of artificial barrier materials such as construction materials for a disposal facility, wastes container, solidification materials for wastes, and so forth, and in fact, they are used for cement solidified matters, concrete pit as a landfill apparatus, and so forth at the Low Level Radioactive Wastes Storage Center situated in Rokkasho-mura, Aomori prefecture. For their disposal, as cement materials are expected for their property on transfer control of radioactive nuclides such as water stoppage, pH buffering of circumferential groundwater, and transfer retarding, except their mechanical properties, it must be quantitatively investigated how they change with time and if their change forms any problem on safety, because a time to consider their soundness on mechanics or nuclide conservation becomes long term such as for more than hundreds years. Under consideration on disposal and technical trends of radioactive wastes in- and out of-Japan described in previous report, after showing on direction of investigation required to make the cement materials function as an artificial material in disposal of radioactive wastes and on technical trends to it, here was summarized on positioning of studies on cement in the disposal business. (G.K.)

  1. Radionuclide migration through porous cement-waste composition in semi-real conditions

    International Nuclear Information System (INIS)

    Plecas, I.; Peric, A.; Kostadinovic, A.

    1989-01-01

    In this paper, result of examination of Leakage rate or radionuclides Co-60 and Cs-137 in semi-real conditions are given. Radionuclides Co-60 and Cs-137 were immobilized by cement process and conditioned in concrete containers trying to make similar scenario for storing radioactive waste materials as in engineering trench system, repository. Experiments were realized with two waste water, evaporator bottom and reactor cooling system, (EB) and (RCS), from Nuclear Power Plants Krsko, in which the main radionuclides are Co-60 and Cs-137. These results will be used for future Yugoslav radioactive waste storing center (author)

  2. Solidification of radioactive waste resins using cement mixed with organic material

    International Nuclear Information System (INIS)

    Laili, Zalina; Yasir, Muhamad Samudi; Wahab, Mohd Abdul

    2015-01-01

    Solidification of radioactive waste resins using cement mixed with organic material i.e. biochar is described in this paper. Different percentage of biochar (0%, 5%, 8%, 11%, 14% and 18%) was investigated in this study. The characteristics such as compressive strength and leaching behavior were examined in order to evaluate the performance of solidified radioactive waste resins. The results showed that the amount of biochar affect the compressive strength of the solidified resins. Based on the data obtained for the leaching experiments performed, only one formulation showed the leached of Cs-134 from the solidified radioactive waste resins

  3. Solidification of radioactive waste resins using cement mixed with organic material

    Energy Technology Data Exchange (ETDEWEB)

    Laili, Zalina, E-mail: liena@nm.gov.my [Nuclear Science Programme, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor Malaysia (Malaysia); Waste and Environmental Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor (Malaysia); Yasir, Muhamad Samudi [Nuclear Science Programme, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor Malaysia (Malaysia); Wahab, Mohd Abdul [Waste and Environmental Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor (Malaysia)

    2015-04-29

    Solidification of radioactive waste resins using cement mixed with organic material i.e. biochar is described in this paper. Different percentage of biochar (0%, 5%, 8%, 11%, 14% and 18%) was investigated in this study. The characteristics such as compressive strength and leaching behavior were examined in order to evaluate the performance of solidified radioactive waste resins. The results showed that the amount of biochar affect the compressive strength of the solidified resins. Based on the data obtained for the leaching experiments performed, only one formulation showed the leached of Cs-134 from the solidified radioactive waste resins.

  4. The Characterization of Filtration Waste Solidified Product from Baghouse Filter of the Incineration Process

    International Nuclear Information System (INIS)

    Sutoto

    2000-01-01

    To increase of the safety, quality and to easy maintenance of the incinerator media of bag house filter, coating of the surface filter media by CaCO 3 powder were done. In the incinerator process, the CaCO 3 powder will scrub of fly ash as secondary waste. And finally, both of the secondary waste and CaCO 3 will immobilized by cement matrix. The research has an objective to study and characterizing of the CaCO 3 as secondary waste on their cemented product. The research were done on block samples with content of CaCO 3 and the properties characterized by compressive strength and density. From this research known that on their solidified, each quantity of CaCO 3 will be impact to decreasing of the quality cementation product. The optimum formula for solidification of bag house filter scrubbed is CaCO 3 : cement: water is 3 : 10 : 7. (author)

  5. Transport of nitrate from a large cement based waste form

    International Nuclear Information System (INIS)

    Pepper, D.W.

    1986-01-01

    A finite-element model is used to calculate the time-dependent transport of nitrate from a cement-based (saltstone) monolith with and without a clay cap. Model predictions agree well with data from two lysimeter field experiments begun in 1984. The clay cap effectively reduces the flux of nitrate from the monolith. Predictions for a landfill monolith design show a peak concentration occurring within 25 years; however, the drinking water guideline is exceeded for 1200 years. Alternate designs and various restrictive liners are being considered

  6. Method of processing liquid waste containing fission product

    International Nuclear Information System (INIS)

    Funabashi, Kiyomi; Kawamura, Fumio; Matsuda, Masami; Komori, Itaru; Miura, Eiichi.

    1988-01-01

    Purpose: To prepare solidification products of low surface dose by removing cesium which is main radioactive nuclides from re-processing plants. Method: Liquid wastes containing a great amount of fission products are generated accompanying the reprocessing for spent nuclear fuels. After pH adjustment, the liquid wastes are sent to a concentrator to concentrate the dissolved ingredients. The concentrated liquid wastes are pumped to an adsorption tower in which radioactive cesium contributing much to the surface dose is removed. Then, the liquid wastes are sent by way of a surge tank to a mixing tank, in which they are mixed under stirring with solidifying agents such as cements. Then, the mixture is filled in a drum-can and solidified. According to this invention, since radioactive cesium is removed before solidification, it is possible to prepare solidification products at low surface dose and facilitate the handling of the solidification products. (Horiuchi, T.)

  7. The Specification of Cement Powders for Waste Encapsulation Processes at Sellafield site

    International Nuclear Information System (INIS)

    Angus, M.; Borwick, J.; Cann, G.; Hayes, M.; McLuckie, B.; Jowsey, J.

    2012-01-01

    Requirements are described for Portland Cement (CEM I), Ground Granulated Blast-furnace Slag (GGBS) and Fly Ash (FA) powders used for the encapsulation of Intermediate Level Radioactive Waste (ILW) in UK, with particular reference to Sellafield site encapsulation processes. Differences between the powders used by the UK nuclear industry and the equivalent British and European cement standards are explained. Research over the last 20 years to respond to changes in the performance of these powders is summarised and options for dealing with potential future changes are discussed. These include the use of special blends of GGBS to achieve the desired flow properties or alternatively poly-carboxylate super-plasticizers to produce grouts with consistent performance using cement powders with a wide range of composition. (authors)

  8. Casting granular ion exchange resins with medium-active waste in cement

    International Nuclear Information System (INIS)

    Beijer, O.

    1980-01-01

    Medium active waste from nuclear power stations in Sweden is trapped in granular ion exchange resins. The resin is mixed with cement paste and cast in a concrete shell which is cubic and has an edge dimension of 1.2 m. In some cases the ion exchange cement mortar has cracked. The report presents laboratory sutdies of the properties of the ion exchange resin and the mortar. Also the leaching of the moulds has been investigated. It was shown that a mixture with a water cement ratio higher than about 0.5 swells considerably during the first weeks after casting. The diffusion constant for cesium 137 has been determined at 3.10 -4 cm 2 /24-hour period in conjunction with exposure of the mould and mortar to sea water. The Swedish language report has 400 pages with 90 figures and 30 tables. (author)

  9. Production of portland cement using Moroccan oil shale and comparative study between conventional cement plant and cement plant using oil shale

    International Nuclear Information System (INIS)

    Doumbouya, M.; Kacemi, K.E.; Kitane, S.

    2012-01-01

    Like the use of coal ash from power plants as an addition to cement, oil shale are used for cement production on an industrial scale in Estonia, China, USA and Germany. Oil shale can be utilized in manufacturing the cement. In addition to the utilization of these by-products after combustion, it can also reduce the required temperature for the clinkering reactions during the production of Portland clinker. We performed a study on the Moroccan oil shale to maximize the use of oil shale ash in the manufacturing of Portland cement. We found that Moroccan oil shale ash can be used up to 30% with 70% Portland clinker without altering its principle properties. The corresponding temperature required to generate the required liquid for the clinkering reactions as well as the essential ingredients for clinker was found to be around 850 to 1000 deg. C. The operating temperatures for this optimized blend ratio were found to 1000 deg. C. The resulting Portland clinker from this ratio will need further testing in accordance with international standards for Portland cement to examine properties like strength and setting time. (author)

  10. Use of hyghly reactive rice husk ash in the production of cement matrix reinforced with Green coconut fiber

    OpenAIRE

    Pereira, C.L.; Savastano, H. Jr; Paya Bernabeu, Jorge Juan; Santos, S. F.; Borrachero Rosado, María Victoria; Monzó Balbuena, José Mª; Soriano Martinez, Lourdes

    2013-01-01

    This study evaluated the influence of partial replacement of Portland cement by rice husk ash (RHA) to enable the use of green coconut husk fiber as reinforcement for cementitious matrix. The use of highly reactive pozzolanic ash contributes for decreasing the alkaline attack on the vegetable fiber, originated from waste materials. The slurry dewatering technique was used for dispersion of the raw materials in aqueous solution, followed by vacuum drainage of water and pressing for the product...

  11. DEVELOPMENT and TESTING OF A CEMENT-BASED SOLID WASTE FORM USING SYNTHETIC UP-1 GROUNDWATER

    International Nuclear Information System (INIS)

    COOKE, G.A.; LOCKREM, L.L.

    2006-01-01

    The Effluent Treatment Facility (ETF) in the 200 East Area of the Hanford Site is investigating the conversion of several liquid waste streams from evaporator operations into solid cement-based waste forms. The cement/waste mixture will be poured into plastic-lined mold boxes. After solidification the bags will be removed from the molds and sealed for land disposal at the Hanford Site. The RJ Lee Group, Inc. Center for Laboratory Sciences (CLS) at Columbia Basin College (CBC) was requested to develop and test a cementitious solids (CS) formulation to solidify evaporated groundwater brine, identified as UP-1, from Basin 43. Laboratory testing of cement/simulant mixtures is required to demonstrate the viability of cement formulations that reduce the overall cost, minimize bleed water and expansion, and provide suitable strength and cure temperature. Technical support provided mixing, testing, and reporting of values for a defined composite solid waste form. In this task, formulations utilizing Basin 43 simulant at varying wt% solids were explored. The initial mixing consisted of making small (∼ 300 g) batches and casting into 500-mL Nalgene(reg s ign) jars. The mixes were cured under adiabatic conditions and checked for bleed water and consistency at recorded time intervals over a 1-week period. After the results from the preliminary mixing, four formulations were selected for further study. The testing documentation included workability, bleed water analysis (volume and pH) after 24 hours, expansivity/shrinkage, compressive strength, and selected Toxicity Characteristic Leaching Procedure (TCLP) leach analytes of the resulting solid waste form

  12. Testing of variables which affect stablity of cement solidified low-level waste

    International Nuclear Information System (INIS)

    Boris, G.F.

    1989-01-01

    This paper describes the test program undertaken to investigate variables which could affect the stability of cement solidified low-level waste and to evaluate the effect of these variables on certain tests prescribed in the Technical Position on Waste Form. The majority of the testing was performed on solidified undepleted bead resin, however, six additional waste types, suggested by the NRC, were tested. The tested variables included waste loading, immersion duration, depletion level, ambient cure duration, curing environment, immersion medium and waste type. Of these, lower waste loadings, longer ambient cures prior to testing and immersion in demineralized water versus simulated sea water and potable water resulted in higher compressive strengths for bead resin samples. Immersion times longer than 90 days did not affect the resin samples. Compressive strengths for other waste types varied depending upon the waste. The strengths of all waste types exceeded the minimum criterion by at least a factor of four, up to a factor of forty. The higher waste loadings exhibit strengths less than the lower waste loadings

  13. Saltstone: cement-based waste form for disposal of Savannah River Plant low-level radioactive salt waste

    International Nuclear Information System (INIS)

    Langton, C.A.

    1984-01-01

    Defense waste processing at the Savannah River Plant will include decontamination and disposal of approximately 400 million liters of waste containing NaNO 3 , NaOH, Na 2 SO 4 , and NaNO 2 . After decontamination, the salt solution is classified as low-level waste. A cement-based waste form, saltstone, has been designed for disposal of Savannah River Plant low-level radioactive salt waste. Bulk properties of this material have been tailored with respect to salt leach rate, permeability, and compressive strength. Microstructure and mineralogy of leached and unleached specimens were characterized by SEM and x-ray diffraction analyses. The disposal system for the DWPF salt waste includes reconstitution of the crystallized salt as a solution containing 32 wt % solids. This solution will be decontaminated to remove 137 Cs and 90 Sr and then stabilized in a cement-based waste form. Laboratory and field tests indicate that this stabilization process greatly reduces the mobility of all of the waste constitutents in the surface and near-surface environment. Engineered trenches for subsurface burial of the saltstone have been designed to ensure compatibility between the waste form and the environment. The total disposal sytem, saltstone-trench-surrounding soil, has been designed to contain radionuclides, Cr, and Hg by both physical encapsulation and chemical fixation mechanisms. Physical encapsulation of the salts is the mechanism employed for controlling N and OH releases. In this way, final disposal of the SRP low-level waste can be achieved and the quality of the groundwater at the perimeter of the disposal site meets EPA drinking water standards

  14. Investigation of Waste Paper Cellulosic Fibers Utilization into Cement Based Building Materials

    Directory of Open Access Journals (Sweden)

    Viola Hospodarova

    2018-03-01

    Full Text Available Recently, the utilization of renewable natural cellulosic materials, such as wood, plants, and waste paper in the preparation of building materials has attracted significant interest. This is due to their advantageous properties, low environmental impact and low cost. The objective of this paper is to investigate the influence of recycled cellulosic fibers (in the amount 0.5 wt % of the filler and binder weight and superplasticizer (in the amount 0.5 wt % of the cement weight on the resulting properties of cement composites (consistency of fresh mixture, density, thermal conductivity, and compressive and flexural strength for hardening times of 1, 3, 7, 28, and 90 days. Plasticizer use improved the workability of fresh cement mixture. In comparison to the reference sample, the results revealed a decrease in density of 6.8% and in the thermal conductivity of composites with cellulosic fibers of 34%. The highest values of compressive (48.4 MPa and flexural (up to 7 MPa strength were achieved for hardened fiber cement specimens with plasticizer due to their significantly better dispersion of cement particles and improved bond strength between fibers and matrix.

  15. Modelling of the degradation of cement in a nuclear waste repository

    International Nuclear Information System (INIS)

    Haworth, A.; Sharland, S.M.; Tweed, C.J.

    1989-01-01

    The current UK concept for a low- or intermediate-level nuclear waste repository includes a largely cementitious backfill. The cement provides a high pH environment in which the general corrosion rate of the metal canisters is reduced and the solubilities of many nuclides low. It has previously been assumed that this high pH will exist for a period of 10 7 years, however cement will degrade due to leaching of the solid components and attack from aqueous species in groundwater. In this paper the authors describe the preliminary stages of a model of the degradation of cement in a repository. The modelling involves the incorporation of a thermodynamic description of cement into the static code PHREEQE. This is then used in a coupled chemistry-transport model of simple leaching of cement using the code CHEQMATE. This preliminary modelling also provides a useful verification of CHEQMATE as a direct comparison with a THCCDM (a coupled code based on CHEMTRN) model is possible. Results from this preliminary model suggest that the fall in pH due to leaching is slow

  16. On the Utilization of Pozzolanic Wastes as an Alternative Resource of Cement

    Directory of Open Access Journals (Sweden)

    Md. Rezaul Karim

    2014-12-01

    Full Text Available Recently, as a supplement of cement, the utilization of pozzolanic materials in cement and concrete manufacturing has increased significantly. This study investigates the scope to use pozzolanic wastes (slag, palm oil fuel ash and rice husk ash as an alkali activated binder (AAB that can be used as an alternative to cement. To activate these materials, sodium hydroxide solution was used at 1.0, 2.5 and 5.0 molar concentration added into the mortar, separately. The required solution was used to maintain the flow of mortar at 110% ± 5%. The consistency and setting time of the AAB-paste were determined. Mortar was tested for its flow, compressive strength, porosity, water absorption and thermal resistance (heating at 700 °C and investigated by scanning electron microscopy. The experimental results reveal that AAB-mortar exhibits less flow than that of ordinary Portland cement (OPC. Surprisingly, AAB-mortars (with 2.5 molar solution achieved a compressive strength of 34.3 MPa at 28 days, while OPC shows that of 43.9 MPa under the same conditions. Although water absorption and porosity of the AAB-mortar are slightly high, it shows excellent thermal resistance compared to OPC. Therefore, based on the test results, it can be concluded that in the presence of a chemical activator, the aforementioned pozzolans can be used as an alternative material for cement.

  17. Research of cement mixtures with additions of industrial by-products

    Science.gov (United States)

    Papesch, R.; Klus, L.; Svoboda, J.; Zajac, R.

    2017-10-01

    The main goal of the article is the comparison of the possible use of secondary energy products. Used fly ashes, respectively steel dusts in cement mixes derive from production in Moravian-Silesian Region. The research focused on their influence on the chemical and physico-mechanical characteristics of the fresh and solid mixture. The aim was to find suitable formulations for grouting works, highway construction possibly rehabilitation of underground cavities created by mining activities. The introduction is mentioned the history of waste utilization up to current use as a product and the overall state of the problem. The conclusion is an evaluation of possible use in practice, including recommendations to carry out further tests.

  18. Mineralogy and chemistry of cement paste in borehole radioactive waste repository

    International Nuclear Information System (INIS)

    Ferreira, Eduardo G.A.; Isiki, Vera L.K.; Miyamoto, Hissae; Marumo, Julio T.; Vicente, Roberto

    2009-01-01

    Results of chemical characterization of cement paste samples after irradiation and immersion in salt solutions are presented. This is part of a research on cement paste behavior aiming at investigating the durability of cementitious materials in the environment of repositories for radioactive waste. Portland cement paste is intended to be used as a backfill in a deep borehole for disposal of sealed radiation sources which concept is under development. The service life of the engineered barrier materials plays an important role in the long term safety of such facilities. Accelerated tests in laboratory are being used to evaluate the performance of cement paste under the temperature expected at some hundred meters below grade, under exposure to the radiation emitted by the sources, and under the attack of aggressive chemicals dissolved in the groundwater, during the millennia necessary for the decay of the most active and long-lived radionuclides present in the waste. ICP-OES, Ion chromatography, X-ray diffraction, SEM and TGA are some techniques being employed in this research project. (author)

  19. Ceramic residue for producing cements, method for the production thereof, and cements containing same

    OpenAIRE

    Sánchez de Rojas, María Isabel; Frías, Moisés; Asensio, Eloy; Medina Martínez, César

    2014-01-01

    [EN] The invention relates to a ceramic residue produced from construction and demolition residues, as a puzzolanic component of cements. The invention also relates to a method for producing said ceramic residues and to another method of producing cements using said residues. This type of residue is collected in recycling plants, where it is managed. This invention facilitates a potential commercial launch.

  20. The influence of mineral additives on the mechanical performances of the conditioning matrix of radioactive waste by cementation

    International Nuclear Information System (INIS)

    Dragolici, F.; Rotarescu, G.; Turcanu, C.N.

    1997-01-01

    To improve the quality of the conditioning matrix of radioactive waste by the cementation technology, mineral additives which are diminishing the leaching rate of the radionuclides in the disposal environment are used. The studies performed until now have as an objective the obtaining of the most propitious mixture of cement and bentonite or cement and volcanic tuff, which have the mechanical properties similar to the cement paste used for the conditioning of the radioactive waste. This mixture, cement - mineral binder, in the future is required to be used at the Radioactive Waste Treatment Plant - IPNE - HH Bucharest- Magurele for the conditioning of the radioactive wastes, taking in consideration the properties of these mineral binders: very good plasticity and capacity of adsorption, which lead at the decrease of porosity. Bentonite is a clay already used in the technology of disposal as a filling material to diminish the radioactive spreading because of degradation in time of the metallic package or the intrusion of casual water. The composition of the cement - bentonite - water system is checked by the cement to water and cement to bentonite ratio, by strength and by the separated water volume. The studies show that the best mechanical performance was obtained for a cement to water ratio 10. Taking in consideration the property of bentonite to fill compactly the free spaces in the presence of water, what entails the occurrence of internal tensions in the matrix structure, which leads, in turn, to appearance of microfissures, the mixtures examined by mechanical tests had in their composition less than 10 % bentonite. For volcanic tuff, similar results were obtained using almost the same ratios. In these conditions, the results obtained allow to draw the conclusion that the adequate usage of the mineral additives do not change the resistance of the cement paste used in the conditioning of the radioactive waste. (authors)

  1. Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement

    International Nuclear Information System (INIS)

    Kruger, A.A.; Olson, R.A.; Tennis, P.D.

    1995-04-01

    Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter, the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO 3 , quartz, and monosulfate Impedance spectra conform with the chemical and mineralogical data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite

  2. Product control of radioactive waste

    International Nuclear Information System (INIS)

    Warnecke, E.; Giller, H.

    1989-09-01

    The aim of the seminar was to give a survey of product quality control and to find out whether the producers/conditioners of waste set and fulfil requirements for the quality of the waste. The program included the following main areas: Random sample tests; Container tests; Process qualification and inspection, and Inspections of waste from fuel element reprocessing abroad. In other lectures, there are reports on measures for producers of waste for guaranteeing the final storage requirements, on quality assurance measurements in the conditioning of waste from large research establishments and from fuel element manufacture. The calling up of waste containers and the documentation of waste data is also introduced. (orig./HP) [de

  3. Geochemical analysis of leachates from cement/low-level radioactive waste/soil systems

    International Nuclear Information System (INIS)

    Criscenti, L.J.; Serne, R.J.

    1988-09-01

    Laboratory experiments were conducted as part of the Special Waste Form Lysimeters/endash/Arid Program. These experiments were conducted to investigate the performance of solidified low-level nuclear waste in a typical arid, near-surface disposal site, and to evaluate the ability of laboratory tests to predict leaching in actual field conditions. Batch leaching, soil adsorption column, and soil/waste form column experiments were conducted using Portland III cement waste forms containing boiling-water reactor evaporator concentrate and ion-exchange resin waste. In order to understand the reaction chemistry of the cement waste form/soil/ground-water system, the compositions of the leachates from the laboratory experiments were studied with the aid of the MINTEQ ion speciation/solubility and mass transfer computer code. The purpose of this report is to describe the changes in leachate composition that occur during the course of the experiments, to discuss the geochemical modeling results, and to explore the factors controlling the major element chemistry of these leachates. 18 refs., 84 figs., 14 tabs

  4. Uses for waste diary products

    Energy Technology Data Exchange (ETDEWEB)

    Burgiss, K J

    1980-06-01

    Processing methods of waste dairy products are described. The major waste dairy product is whey, which is said to account for 20% of the total volume of milk processed. Individual methods of whey processing include the manufacture of lactose, whey demineralization in the preparation of babyfood, whey protein recovery by ultrafiltration and alcohol production. Two new techniques, lactose hydrolysis to increase the sweetness of lactose and reverse osmosis for concentration are also mentioned.

  5. Development, testing, and demonstration of geotechnical and cement-based encapsulant materials for the stabilization of radioactive and hazardous waste disposal structures

    International Nuclear Information System (INIS)

    Phillips, S.J.; Cammann, J.W.; Benny, H.L.; Serne, R.J.; Martin, P.F.; Ames, L.L.

    1991-09-01

    A zeolite fluidized-bed treatment system is being developed and tested for the treatment of radioactive and hazardous waste-contaminated subsurface disposal structures. Formulations of cement, fly ash, and slag slurries and sequestering agents also are being tested and evaluated. Leach resistance of radionuclides, heavy metals, and hazardous inorganic compounds in the solidified cement-based encapsulant has been determined. These results simulate the resistance to water leaching of the solidified product after it has been injected an open and interstitial void volume in and proximal to liquid waste disposal structures. Micro- and macro-encapsulation of contaminants within and geologic media surrounding subsurface disposal structures is being demonstrated as an alternative technology for waste site remediation. 5 refs., 1 fig., 1 tab

  6. Production of a calcium silicate cement material from alginate impression material.

    Science.gov (United States)

    Washizawa, Norimasa; Narusawa, Hideaki; Tamaki, Yukimichi; Miyazaki, Takashi

    2012-01-01

    The purpose of this study was to synthesize biomaterials from daily dental waste. Since alginate impression material contains silica and calcium salts, we aimed to synthesize calcium silicate cement from alginate impression material. Gypsum-based investment material was also investigated as control. X-ray diffraction analyses revealed that although firing the set gypsum-based and modified investment materials at 1,200°C produced calcium silicates, firing the set alginate impression material did not. However, we succeeded when firing the set blend of pre-fired set alginate impression material and gypsum at 1,200°C. SEM observations of the powder revealed that the featured porous structures of diatomite as an alginate impression material component appeared useful for synthesizing calcium silicates. Experimentally fabricated calcium silicate powder was successfully mixed with phosphoric acid solution and set by depositing the brushite. Therefore, we conclude that the production of calcium silicate cement material is possible from waste alginate impression material.

  7. Final disposal of low and intermediate radioactive waste - aspects of diffusion through cement lattice modelling

    International Nuclear Information System (INIS)

    Mihai, C.

    1998-01-01

    The present work performed in our department is related to development of safety assessment programme for the National Repository for Radioactive Waste - Baita, Bihor. The rate of radionuclide release in the proximity of National Repository for Radioactive Waste - Baita, Bihor was minimized by taking into account the multibarrier principle. This implies the uses of a complex system of natural and engineered barriers which should neutralize the main processes of radionuclide migration. In the first component of the system mentioned above, cement lattice, the migration of incorporated radionuclides takes place mainly by diffusion process. The diffusion equation is given for the particular case of cylindrical shape of the container, from which the ratio between the released fraction and the initial quantity of radionuclides is obtained. We studied the process of diffusion in three different materials (the radionuclides used were 65 Zn, 51 Cr, 82 Br). The results obtained allowed a pertinent selection of the material for improvement of retardation factors of cement lattice. (author)

  8. Low-level waste cement solidification design, installation, and start-up

    International Nuclear Information System (INIS)

    Jezek, G.R.

    1988-08-01

    This report describes the design, installation, and start-up activities of the Cement Solidification System (CSS) at the West Valley Demonstration Project (WVDP), West Valley, New York. The CSS, designed to operate within an existing process cell, automatically and remotely solidifies low-level nuclear waste by mixing it with Portland Type I cement. The qualified waste form mixture is placed into square, 270-litre (71-gallon) metal drums. The drums have an integral polyethylene liner to protect the carbon-steel material from potential corrosion. The CSS produces drums at a continuous operation rate of four drums per hour. All system processing data is monitored by a computerized Data Acquisition System (DAS). 6 figs

  9. Tritium transport in subsurface soil and its retentivity in cement waste forms

    International Nuclear Information System (INIS)

    Varghese, C.; Khan, Z.A.

    1990-01-01

    Tritiated aqueous wastes generated from power reactors and reprocessing plants need fixation and containment in solid media. Incorporating tritium in inorganic hydrates like cement retards its movements substantially. Naturally occurring clay mineral like vermiculite which has high water holding capacity was used as a filler material. To improve the retention of tritium in the cement blocks, certain coating materials were used after curing the blocks for 28 days. Long time leach tests for these barrier incorporated wastes forms have shown tritium releases of 17% loaded tritium over a period of 97 days. But the selected coating reduced it to 0.9%. Investigations on the movements of tritium at Tarapur and Narora revealed that in the unsaturated zone, tritium percolation was low, whereas in the saturated zone, it was found to travel with higher velocities, limiting to ground water movement. (author). 5 refs., 3 tabs

  10. Improved cement mortars by addition of carbonated fly ash from solid waste incinerators

    Directory of Open Access Journals (Sweden)

    López-Zaldívar, O.

    2015-09-01

    Full Text Available This article presents the results of a research developing high performance cement mortars with the addition of municipal solid waste incineration fly ash (MSWIFA stabilized as insoluble carbonates. The encapsulation of hazardous wastes in mortar matrixes has also been achieved. The ashes present high concentrations of chlorides, Zn and Pb. A stabilization process with NaHCO3 has been developed reducing 99% the content of chlorides. Developed mortars replace 10% per weight of the aggregates by treated MSWIFA. Physical/mechanical properties of these mortars have been studied. Presence of Zn, Pb, Cu and Cd has been also analyzed confirming that leaching of these heavy metal ions is mitigated. Conclusions prove better behavior of CAC and CSA mortars than those of CEM-I and CEM-II cement. Results are remarkable for the CAC mortars, improving reference strengths in more than 25%, which make them a fast-curing product suitable for the repair of structures or industrial pavements.Este artículo presenta los resultados del desarrollo de morteros mejorados con la incorporación de cenizas volantes de residuos sólidos urbanos inertizadas en forma de carbonatos. Además se consigue la encapsulación de un residuo peligroso. Las cenizas presentan una alta concentración de cloruros, Zn y Pb. Se ha desarrollado un proceso de estabilización con NaHCO3 reduciendo en un 99% el contenido de cloruros. Los morteros reemplazan un 10% en peso del árido por cenizas tratadas. Se han analizado sus propiedades físico/mecánicas y la presencia de Zn, Pb, Cu y Cd. Se demuestra un mejor comportamiento de los morteros de CAC y CSA que los de CEM-I y CEM-II y se mitiga el lixiviado de metales pesados. Los resultados son significativos en los morteros CAC al mejorar las resistencias de los de referencia en un 25%. Los morteros desarrollados son de curado rápido adecuados para la reparación de estructuras o soleras industriales.

  11. Determination of the leaching rate of radionuclide 134Cs from the solidified radioactive wastes in Syrian Portland cement and cement-microsilica matrixes

    International Nuclear Information System (INIS)

    Ismail Shaaban; Nasim Assi

    2010-01-01

    The suitability of Syrian Portland cement for disposal of solidified low-level radioactive waste was assessed by measuring the leaching rate of 134 Cs. In ordinary cement concrete, a leaching rate of 1.309 x 10 -3 g/cm 2 per day was measured. Mixing this concrete with microsilica reduced significantly the leaching rate to 3.106 x 10 -4 g/cm 2 per day for 1% mixing, and to 9.645 x 10 -5 g/cm 2 per day for 3% mixing. It was also found that the application of a latex paint reduced these leaching rates by about 10%. These results, along with mechanical strength tests (under radiation exposure, high temperature, long water immersion and freeze-thaw cycling) indicate that Syrian Portland cement is suited for the disposal of low-level radioactive waste. (author)

  12. Development of low-activation design method for reduction of radioactive waste (4). Development of low-activation cement

    International Nuclear Information System (INIS)

    Ichitsubo, Koki; Tanosaki, Takao; Miura, Keiichi; Tomotake, Hiroichi; Yamada, Kazunori; Fujita, Hideki; Kinno, Masaharu; Hasegawa, Akira

    2008-01-01

    When nuclear plants will reach to decommission stage, a huge amount of concrete should be disposed as radioactive waste. To reduce the amount of radioactive concrete, the most effective methodology is not to use the materials of high radionuclide content such as coal ash and blast furnace slag, and to use limestone as additives or aggregate. However, concrete uses Portland cement for hardening, therefore, it is difficult to reduce the amount of radioactive concrete unless radionuclide content in cement is reduced. So in this study, we tried to develop the new type of Low-activation cement by reducing of radionuclide as europium and cobalt. As a result, we could reduce the amount of europium and cobalt in cement significantly, and obtained the result that the new cements can reduce radioactivity to one-third or less against commercially Portland cement in Japan. (author)

  13. Some aspects about the Portland cement utilization as a matrix for radioactive waste immobilization

    International Nuclear Information System (INIS)

    Giraldelli, M.A.

    1990-01-01

    More recently, the environmental policy has concentrated the focus on the study of the waste disposal environmental impact. Since Portland cement is commonly used as a matrix in the low-and intermediate-level radioactive waste immobilization, in the present work, some relationships between the structure and properties of matrix, based on available concrete technology information, has been established by using the multi-level approach analysis. The relationships were developed based on hydrating reactions, the microstructure models, the pore system. It have been verified that: a) CSH gel is responsible for the cementing action and for the strength; b) it seems that the capillary porosity is the strength limiting; c) the permeability, regarded in terms of gel porosity and reduced capillary porosity of the hardened cement paste, may not be a decisive factor for the radionuclide release; d) the shrinkage and the swelling induced cracks can enhance the diffusion mechanism for the cracks increase the exposed surface. The durability of the waste disposal matrix concerning chemical attack in the acidic environment has been considered. (author)

  14. Ettringite and C-S-H Portland cement phases for waste ion immobilization: A review

    International Nuclear Information System (INIS)

    Gougar, M.L.D.; Scheetz, B.E.; Roy, D.M.

    1996-01-01

    The formation, structure and chemistry of the ettringite and C-S-H phases of Portland cement have been reviewed as they relate to waste ion immobilization. The purpose of this review was to investigate the use of Portland cement as a host for priority metallic pollutants as identified by the Environmental Protection Agency and as a host for radioactive waste ions as identified in 40 CFR 191. Ettringite acts as host to a number of these ions in both the columnar and channel sections of the crystal structure. Substitutions have been made at the calcium, aluminum, hydroxide and sulfate sites. C-S-H also hosts a number of the waste species in both ionic and salt form. Immobilization mechanisms for C-S-H include sorption, phase mixing and substitution. The following ions have not apparently been reported as specifically immobilized by one of these phases: Ag, Am, Np, Pu, Ra, Tc, Th and Sn; however, some of these ions are immobilized by Portland cement

  15. Alcohol production from pineapple waste

    Energy Technology Data Exchange (ETDEWEB)

    Ban-Koffi, L. (Ministry of Scientific Research, Abidjan (CI). Ivorian Center of Technological Research); Han, Y.W. (USDA, Southern Regional Research Center, New Orleans, LA (US))

    1990-09-01

    Saccharomyces cerevisiae and Zymomonas mobilis were grown on pineapple waste and their alcohol production characteristics compared. The pineapple waste consisted of 19% cellulose, 22% hemi-cellulose, 5% lignin and 53% cell soluble matters but concentration of soluble sugars, which included 5.2% sucrose, 3.1% glucose and 3.4% fructose, was relatively low and pretreatment of the substrate was needed. Pretreatment of pineapple waste with cellulase and hemi-cellulase and then fermentation with S. cerevisiae or Z. mobilis produced about 8% ethanol from pineapple waste in 48 h. (author).

  16. Estimation of CO2 emissions from China’s cement production: Methodologies and uncertainties

    International Nuclear Information System (INIS)

    Ke, Jing; McNeil, Michael; Price, Lynn; Khanna, Nina Zheng; Zhou, Nan

    2013-01-01

    In 2010, China’s cement output was 1.9 Gt, which accounted for 56% of world cement production. Total carbon dioxide (CO 2 ) emissions from Chinese cement production could therefore exceed 1.2 Gt. The magnitude of emissions from this single industrial sector in one country underscores the need to understand the uncertainty of current estimates of cement emissions in China. This paper compares several methodologies for calculating CO 2 emissions from cement production, including the three main components of emissions: direct emissions from the calcination process for clinker production, direct emissions from fossil fuel combustion and indirect emissions from electricity consumption. This paper examines in detail the differences between common methodologies for each emission component, and considers their effect on total emissions. We then evaluate the overall level of uncertainty implied by the differences among methodologies according to recommendations of the Joint Committee for Guides in Metrology. We find a relative uncertainty in China’s cement-related emissions in the range of 10 to 18%. This result highlights the importance of understanding and refining methods of estimating emissions in this important industrial sector. - Highlights: ► CO 2 emission estimates are critical given China’s cement production scale. ► Methodological differences for emission components are compared. ► Results show relative uncertainty in China’s cement-related emissions of about 10%. ► IPCC Guidelines and CSI Cement CO 2 and Energy Protocol are recommended

  17. Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste

    Science.gov (United States)

    Duffó, G. S.; Farina, S. B.; Schulz, F. M.

    2013-07-01

    Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums. The corrosion rate of the steel in contact with cemented ion-exchange resins in the absence of contaminants or in the presence of 2.3 wt.% sulphate content remains low (less than 0.1 μm/year) during the whole period of the study (900 days). The presence of chloride ions increases the corrosion rate of the steel at the beginning of the exposure but, after 1 year, the corrosion rate drops abruptly reaching a value close to 0.1 μm/year. This is probably due to the lack of water to sustain the corrosion process. When applying the results obtained in the present work to estimate the corrosion depth of the steel drums containing the cemented radioactive waste after a period of 300 years, it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums. Cementation of ion-exchange resins does not seem to pose special risks regarding the corrosion of the steel drums that contained them; even in the case the matrix is highly contaminated with chloride ions.

  18. Evaluation of the properties of cemented low level radioactive wastes through an extensive characterization programme

    International Nuclear Information System (INIS)

    Caropreso, G.; De Angelis, G.

    1990-01-01

    The immobilized radioactive wastes have to fulfill the demands for packing, interim storage, trasportation and final disposal. For this purpose the possession of various properties, more or less relevant, are required by authorized agencies. In addition to transport regulations the attention is generally focused on physico-chemical and mechanical properties, thermal, radiation and water stability, as well as confinement ability. The assessment of such requirements needs the set up of experimental procedured. With this in mind an extensive programme for the characterization of cemented low level wastes has been undertaken at ENEA Casaccia in the frame of the Third (1985-1989) Europen Communities Programme on Radioactive Waste Management (Contract No. FI1W-0101-I(A)). Three types of waste streams of general interest have been taken into account: bead ion-exchange resins, BWR evaporator concentrates (Sulphates) and filter sludges. Both labo. and full scale experiments have been carried out

  19. Examination of the jarosite-alunite precipitate addition in the raw meal for the production of sulfoaluminate cement clinker.

    Science.gov (United States)

    Katsioti, M; Tsakiridis, P E; Leonardou-Agatzini, S; Oustadakis, P

    2006-04-17

    The aim of the present research work was to investigate the possibility of adding a jarosite-alunite chemical precipitate, a waste product of a new hydrometallurgical process developed to treat economically low-grade nickel oxides ores, in the raw meal for the production of sulfoaluminate cement clinker. For that reason, two samples of raw meals were prepared, one contained 20% gypsum, as a reference sample ((SAC)Ref) and another with 11.31% jarosite-alunite precipitate ((SAC)J/A). Both raw meals were sintered at 1300 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the jarosite-alunite precipitate did not affect the mineralogical characteristics of the so produced sulfoaluminate cement clinker and there was confirmed the formation of the sulfoaluminate phase (C4A3S), the most typical phase of this cement type. Furthermore, both clinkers were tested by determining the grindability, setting time, compressive strength and expansibility. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of jarosite-alunite precipitate did not negatively affect the quality of the produced cement.

  20. The use of mexican cements in the low and medium radioactive wastes confinement; La utilizacion de cementos mexicanos en el confinamiento de desechos radioactivos de bajo y medio nivel

    Energy Technology Data Exchange (ETDEWEB)

    Badillo A, V.E.; Almazan T, M.G.; Alonso V, G.; Palacios H, J.C. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2008-07-01

    Inside the relative mark to the radioactive waste confinement, minerals of great fixation capacity like clays, apatites and diverse oxides are studied as matrixes, components and/or additives of the active barriers that separate the barrier geologic and the nuclear wastes. In this case, the cements intervene in those different stages of the waste management, since its are used for the immobilization of radioactive waste in the container, for the production of containers as well as filler of the spaces among the containers of the vaults, and also as engineering barrier and construction material in the civil work. For the above mentioned, it is particularly useful to characterize the Portland cements with at least 97% of clinker, since they are most recommended for this type of applications. Presently investigation work is carried out a preliminary chemical characterization, based on the mineralogical composition, of the Portland Mexican cement. Results are shown by the X-ray Diffraction technique when immobilizing a rich solution in sulfates to 5%, using two Portland commercial cements APASCO and TOLTECA, without observing the significant appearance of new phases. The cements besides incorporating the chemical species in the breast of the matrix, are also present as barriers of civil engineering in the facilities located only some meters deep for the storage of radioactive waste of low and intermediate level, for that the study of the radionuclides fixation, in the cements is of supreme importance to evaluate the safety of a nuclear repository with the help of cements; the retention of the iodine-131 in a limited interval of pH in the commercial APASCO and TOLTECA it was studied, being observed a scarce retention of this homologous of fission products, what indicates the necessity to use additives to improve the retention properties of the Mexican commercial cements for some radionuclides. (Author)

  1. Cement mortar-degraded spinney waste composite as a matrix for immobilizing some low and intermediate level radioactive wastes: Consistency under frost attack

    International Nuclear Information System (INIS)

    Eskander, S.B.; Saleh, H.M.

    2012-01-01

    Highlights: ► Spinney fiber is one of the wastes generated from spinning of cotton raw materials. ► Cement mortar composite was hydrated by using the degraded slurry of spinney wastes. ► Frost resistance was assessed for the mortar-degraded spinney waste composite specimens. ► SEM image, FT-IR and XRD patterns were performed for samples subjected to frost attack. - Abstract: The increasing amounts of spinning waste fibers generated from cotton fabrication are problematic subject. Simultaneous shortage in the landfill disposal space is also the most problem associated with dumping of these wastes. Cement mortar composite was developed by hydrating mortar components using the waste slurry obtained from wet oxidative degradation of these spinney wastes. The consistency of obtained composite was determined under freeze–thaw events. Frost resistance was assessed for the mortar composite specimens by evaluating its compressive strength, apparent porosity and mass loss at the end of each period of freeze–thaw up to 45 cycles. Scanning electron microscopy, infrared spectroscopy and X-ray diffraction analyses were performed for samples subjected to frost attack aiming at evaluating the cement mortar in the presence of degraded spinney waste. The cement mortar composite exhibits acceptable resistance and durability against the freeze–thaw treatment that could be chosen in radioactive waste management as immobilizing agent for some low and intermediate level radioactive wastes.

  2. Mineralogy and microstructure of two Mexican Portland cements for the confinement of radioactive waste; Mineralogia y microestructura de dos cementos mexicanos Portland para el confinamiento de desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Galicia A, E. [Universidad Autonoma del Estado de Mexico, Facultad de Ciencias, Campus El Cerrillo, Piedras Blancas, Carretera Toluca-Ixtlahuaca Km. 15.5, Estado de Mexico (Mexico); Badillo A, V. E.; Ramirez S, J. R. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Nava E, N., E-mail: nasiega_181@hotmail.com [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, 07730 Mexico D. F. (Mexico)

    2014-10-15

    The cementitious materials are involved in the different stages of radioactive waste management because they are used for the waste immobilization in the container, as well as filling in the spaces between containers vaults and also as engineering barrier and construction material in civil construction site. Therefore, is necessary to have a study of commercial cement available nationwide involving solid timely analysis in order to identify which phases are responsible for confinement of radionuclides, if considered the most reactive phase -CSH- or called secondary phases. In this research the hydration products of cement are presented as well as its importance in the nuclear industry. The analysis and observation of the cement clinker and the hydration products on the manufactured pulps with two commercial cements resistant to sulphates was realized using the observation technique of solid X-ray diffraction and nuclear analytic techniques of Moessbauer spectroscopy and X-Ray Fluorescence. The results show the presence of calcium silicate hydrates in the amorphous phase and the presence of ettringite crystals and portlandite sheets is appreciated. The abundant iron phase called tetra calcium ferro aluminate has been identified by Moessbauer spectroscopy. (Author)

  3. Passengers waste production during flights.

    Science.gov (United States)

    Tofalli, Niki; Loizia, Pantelitsa; Zorpas, Antonis A

    2017-12-20

    We assume that during flights the amount of waste that is produced is limited. However, daily, approximately 8000 commercial airplanes fly above Europe's airspace while at the same time, more than 17,000 commercial flights exist in the entire world. Using primary data from airlines, which use the Larnaca's International Airport (LIA) in Cyprus, we have tried to understand why wastes are produced during a typical flight such as food waste, paper, and plastics, as well as how passengers affect the production of those wastes. The compositional analysis took place on 27 flights of 4 different airlines which used LIA as final destination. The evaluation indicated that the passenger's habits and ethics, and the policy of each airline produced different kinds of waste during the flights and especially food waste (FW). Furthermore, it was observed that the only waste management strategy that exists in place in the airport is the collection and the transportation of all those wastes from aircrafts and from the airport in the central unit for further treatment. Hence, this research indicated extremely difficulties to implement any specific waste minimization, or prevention practice or other sorting methods during the flights due to the limited time of the most flights (less than 3 h), the limited available space within the aircrafts, and the strictly safety roles that exist during the flights.

  4. PHYSICO-CHEMICALANALYSIS OF THE CASHEW NUT PRODUCTION WASTE AIMING THEIR USE IN CEMENT COMPOSITES / ANÁLISE FÍSICO-QUÍMICA DA CINZA DA CASCA DA CASTANHA DE CAJU VISANDO SUAAPLICAÇÃO EM MATERIAIS CIMENTÍCIOS

    Directory of Open Access Journals (Sweden)

    SOFIA ARAÚJO LIMA

    2009-11-01

    Full Text Available Ashes have a prominent place among the agroindustrial wastes, as they result from the energy generation process. Most ashes have pozzolanic activity, and may be used as a cement replacement material, resulting in less energy waste and low cost composite. The present paper investigates the physical and chemical properties of cashew nut shell ash (CNSA by the following measurement tests: chemical analysis, bulk density, specific mass, leaching and solubilization process, X-Ray diffraction (XRD, scanning electron microscopy (SEM and specific surface area (BET. A low content of silicon (SiO2 was observed by means of the chemical tests and heavy metals were found in the analysis of the CNSA solubilized extract. These results will be important for the determination of the pozzolanicity of CNSA in a next stage, as well as the development of a new product for civil building reducing the solubilization of the CNSA in the environment. 

  5. Leaching experiment of cement solidified waste form under unsaturated condition

    International Nuclear Information System (INIS)

    Wang Zhiming; Yao Laigen; Li Shushen; Zhao Yingjie; Cai Yun; Li Dan; Han Xinsheng; An Yongfeng

    2003-01-01

    A device for unsaturated leaching experiments was designed and built up. 8 different sizes, ranging from 40.2 cm 3 to 16945.5 cm 3 , of solidified waste form were tested in the experiment. 5 different water contents, from 0.15 to 0.40, were used for the experiment. The results show that the cumulative leaching fraction increases with water content when the sizes of the forms are equal to and less than 4586.7 cm 3 , for example, the ratios of the cumulative leaching fractions are between 1.24-1.41 under water content of 0.35 and 0.15 on 360 day of Teaching. It can also be seen that the cumulative leaching fraction under higher water content is close to that under saturated condition. The cumulative leaching fraction decreases with size of the form. Maximum leached depth of the solidified waste forms is about 2.25 cm after one year Teaching. Moreover, it has no clear effect on cumulative leaching fraction that sampling or non-sampling during the experiment

  6. Development of methodology to evaluate microbially influenced degradation of cement-solidified low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Rogers, R.D.; Hamilton, M.A.; Veeh, R.H.; McConnell, J.W.

    1994-01-01

    Because of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. An environmentally mediated process that could affect cement stability is the action of naturally occurring microorganisms. The US Nuclear Regulatory Commission (NRC), recognizing this eventuality, stated that the effects of microbial action on waste form integrity must be addressed. This paper provides present results from an ongoing program that addresses the effects of microbially influenced degradation (MID) on cement-solidified LLW. Data are provided on the development of an evaluation method using acid-producing bacteria. Results are from work with one type of these bacteria, the sulfur-oxidizing Thiobacillus. This work involved the use of a system in which laboratory- and vendor-manufactured, simulated waste forms were exposed on an intermittent basis to media containing thiobacilli. Testing demonstrated that MID has the potential to severely compromise the structural integrity of ion-exchange resin and evaporator-bottoms waste that is solidified with cement. In addition, it was found that a significant percentage of calcium and other elements were leached from the treated waste forms. Also, the surface pH of the treated specimens decreased to below 2. These conditions apparently contributed to the physical deterioration of simulated waste forms after 60 days of exposure to the thiobacilli

  7. Influence of Waste Glass Powder Addition on the Pore Structure and Service Properties of Cement Mortars

    Directory of Open Access Journals (Sweden)

    José Marcos Ortega

    2018-03-01

    Full Text Available At present, reusing waste constitutes an important challenge in order to reach a more sustainable environment. The cement industry is an important pollutant industrial sector. Therefore, the reduction of its CO2 emissions is now a popular topic of study. One way to lessen those emissions is partially replacing clinker with other materials. In this regard, the reuse of waste glass powder as a clinker replacement could be possible. This is a non-biodegradable residue that permanently occupies a large amount of space in dumping sites. The aim of this work is to study the long-term effects (400 days of the addition of waste glass powder on the microstructure and service properties of mortars that incorporate up to 20% of this addition as clinker replacement. The microstructure has been characterised using the non-destructive impedance spectroscopy technique and mercury intrusion porosimetry. Furthermore, differential thermal analysis was also performed. Compressive strength and both steady-state and non-steady-state chloride diffusion coefficients have also been determined. Considering the obtained results, mortars with 10% and 20% waste glass powder showed good service properties until 400 days, similar to or even better than those made with ordinary Portland cement without additions, with the added value of contributing to sustainability.

  8. Waste Cellulose from Tetra Pak Packages as Reinforcement of Cement Concrete

    Directory of Open Access Journals (Sweden)

    Gonzalo Martínez-Barrera

    2015-01-01

    Full Text Available The development of the packaging industry has promoted indiscriminately the use of disposable packing as Tetra Pak, which after a very short useful life turns into garbage, helping to spoil the environment. One of the known processes that can be used for achievement of the compatibility between waste materials and the environment is the gamma radiation, which had proved to be a good tool for modification of physicochemical properties of materials. The aim of this work is to study the effects of waste cellulose from Tetra Pak packing and gamma radiation on the mechanical properties of cement concrete. Concrete specimens were elaborated with waste cellulose at concentrations of 3, 5, and 7 wt% and irradiated at 200, 250, and 300 kGy of gamma dose. The results show highest improvement on the mechanical properties for concrete with 3 wt% of waste cellulose and irradiated at 300 kGy; such improvements were related with the surface morphology of fracture zones of cement concrete observed by SEM microscopy.

  9. An examination of sulfur polymer cement as a waste encapsulation agent

    International Nuclear Information System (INIS)

    McNew, E.B.

    1995-01-01

    Sulfur polymer cement (SPC) is a unique material having potential applications for hazardous and radioactive waste encapsulation. This material was originally developed by the US Bureau of Mines as an acid and chemical resistant construction cement and has since been applied in tie waste encapsulation field. The material is easily prepared from elemental sulfur and organic dienes. It is an easy to use low-viscosity thermoplastic, and has many favorable properties such as low porosity, high compressive strength, and resistance to chemical attack. The results of several invetigations on this material will be discussed, and include: (1) the chemical form and physical structure of the material, (2) the compressive strength of cylindrical test samples after gamma radiation testing, (3) the aqueous leaching behavior of lead, cerium, cesium, cobalt, and strontium from SPC-ash mixtures at room and elevated temperatures, (4) the casting compatibility of mixtures of SPC with different waste materials, (5) the ability of SPC to encapsulate elemental mercury contaminated soils, (6) laboratory and field studies of SPC biocorrosion by Thiobacillus bacteria, (7) small scale (10 kg) SPC-ash monolith casting studies, and (8) methods for the formulation of a grade of SPC more applicable to the encapsulation of aggregate waste materials

  10. Development of low-alkaline cement using pozzolans for geological disposal of long-lived radioactive waste

    International Nuclear Information System (INIS)

    Mihara, Morihiro; Iriya, Keishiro; Torii, Kazuyuki

    2008-01-01

    To reduce uncertainties in the safety assessment of the disposal system for long-lived radioactive waste, cement was developed which generates leachates with a lower pH than that of ordinary cement paste. This cement is termed 'low-alkaline cement'. Large amounts of pozzolans were used to produce the low-alkaline cement with ordinary Portland cement. Silica fume was found to be an effective pozzolans to reduce pH, but the needed large amount of silica fume reduced the workability of fresh concrete. Therefore, the authors also used fly ash with silica fume, to develop more workable low-alkaline cement, termed high-volume fly ash silica fume cement (HFSC). Two types of HFSC developed showed high compressive strength, smaller drying shrinkage and lower temperature rise than that of ordinary Portland cement. It was confirmed that HFSC could be used as self-compacting concrete. Therefore they can be applied as either structural or backfilling concrete in the disposal system. (author)

  11. Polyhydroxyalkanoate (PHA) production from waste.

    Science.gov (United States)

    Rhu, D H; Lee, W H; Kim, J Y; Choi, E

    2003-01-01

    PHA (polyhydroxyalkanoate) production was attempted with SBRs from food waste. Seed microbes were collected from a sewage treatment plant with a biological nutrient removal process, and acclimated with synthetic substrate prior to the application of the fermented food waste. Laboratory SBRs were used to produce PHA with limited oxygen and nutrients. The maximum content of 51% PHA was obtained with an anaerobic/aerobic cycle with P limitation, and the yield was estimated to be about 0.05 gPHA(produced)/gCOD(applied) or 25 kg PHA/dry ton of food waste, assuming more than 40% of the PHA contents were recoverable. PHB/PHA ratios were 0.74 to 0.77 due to the higher acetate concentrations. Economical analysis seemed to suggest the PHA produced from the food waste could be an alternative material to produce the biodegradable plastic to be used for the collection bags for solid waste.

  12. Cement matrix solidification of decontamination ion-exchange resin waste

    International Nuclear Information System (INIS)

    Holt, N. S.; Hebditch, D. J.

    1991-01-01

    Crossflow membrane separation has been evaluated as an alternative to more conventional separation methods for the removal of oil from nuclear power station aqueous effluents and liquid wastes. Three commercially available membranes were investigated at small pilot scale; sintered metal power and metal fibre membranes, both of tubular geometries, and hollow fibre polypropylene. The sintered powder membrane gave by far the best oil water separation performance. Less than 10 ppm oil in the aqueous permeate was readily achieved and the oil was concentrated up to 75% by volume from feed concentrations in the range 1000 ppm to 10%. The presence of solids was found to have a profound influence on permeation rates. On the basis of the data presented, a single stage scheme for the treatment of oily effluents is proposed

  13. Evaluating the freeze-thaw durability of portland cement-stabilized-solidified heavy metal waste using acoustic measurements

    International Nuclear Information System (INIS)

    El-Korchi, T.; Gress, D.; Baldwin, K.; Bishop, P.

    1989-01-01

    The use of stress wave propagation to assess freeze-thaw resistance of portland cement solidified/stabilized waste is presented. The stress wave technique is sensitive to the internal structure of the specimens and would detect structural deterioration independent of weight loss or visual observations. The freeze-thaw resistance of a cement-solidified cadmium waste and a control was evaluated. The control and cadmium wastes both showed poor freeze-thaw resistance. However, the addition of cadmium and seawater curing increased the resistance to more cycles of freezing and thawing. This is attributed to microstructural changes

  14. A preliminary assessment of polymer-modified cements for use in immobilisation of intermediate level radioactive waste

    International Nuclear Information System (INIS)

    Burnay, S.G.; Dyson, J.R.

    1982-11-01

    A range of polymer-modified cements has been examined as candidate materials for the immobilisation of intermediate level radioactive waste. The waste streams studied were inactive simulates of real wastes and included ion-exchange resins, Magnox debris and dilute sludges. Preliminary experiments on the compatibility of the polymer-cement-waste combinations have been carried out and measurements of flexural strength before and after #betta#-irradiation to 10 9 rad and water immersion have been made. Soxhlet leach tests have been used to compare the leach rates of the different materials. From the results of these preliminary experiments, a limited number of polymer-modified cements have been suggested as suitable for more detailed study. (author)

  15. Bitumen coating as a tool for improving the porosity and chemical stability of simulated cement-waste forms

    International Nuclear Information System (INIS)

    Saleh, H.M.

    2010-01-01

    Coating process of simulated cement-based waste form with bitumen was evaluated by performing physical and chemical experimental tests. X-ray diffraction (X-RD), Fourier transform infrared spectroscopy (FT-IR) and electron microscope investigations were applied on coated and non-coated simulated waste forms. Experimental results indicated that coating process improved the applicable properties of cement-based waste form such as porosity and leachability. Diffusion coefficients and leach indecies of coated specimens were calculated and show acceptable records. It could be stated that coating cemented waste form by bitumen emulsion, isolate the radioactive contaminants, thus reduces their back release to surrounding and in consequently save the environment proper and safe

  16. Pollution impact of cement production on air, soil and water in a ...

    African Journals Online (AJOL)

    Pollution impact of cement production on air, soil and water in a production location in Nigeria. ... Journal of Science and Technology (Ghana) ... location from the pollution source, which served as control for particulate and soil sampling.

  17. The effects of temperature on the leaching behavior of cement waste forms: The cement/sodium sulfate system

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Pietrzak, R.; Heiser, J.; Franz, E.M.; Colombo, P.

    1989-10-01

    The leaching mechanisms of simulated low-level radioactive waste forms are being determined as support for development of an accelerated leach test. Two approaches are being used: (1) comparisons of leaching data with results of a model that describes diffusion from a finite cylinder, and (2) observation of the leaching process at temperatures between 20 degree C and 65 degree C. To provide results that can be used for modeling, leaching at elevated temperatures must change neither the leaching mechanism nor the structural controls of leaching such as the porosity. Releases of 137 Cs, 85 Sr, calcium, sodium and potassium from portland cement containing sodium sulfate, as a simulated evaporator sludge, have been determined under a variety of experimental conditions. Data from the leach tests were compared to model results for diffusion from the finite cylinder. While most leaching appears to be diffusion controlled, notable exceptions occur. For all samples activation energies ranging between 6 and 11 Kcal/mole have been calculated from the relationship of the effective diffusion coefficient to increasing temperature, close to the expected value of 5 Kcal/mole for diffusion. 11 refs., 4 figs., 2 tabs

  18. Leaching due to hygroscopic water uptake in cemented waste containing soluble salts

    DEFF Research Database (Denmark)

    Brodersen, K.

    1992-01-01

    conditions, condensation of water vapour will result in generation of a certain amount of liquid in the form of a strong salt solution. The volume of liquid may well exceed the storage capacity of the pore system in the cemented material and in the release of a limited amount of free contaminated solution......Considerable amounts of easily soluble salts such as sodium nitrate, sulphate, or carbonate are introduced into certain types of cemented waste. When such materials are stored in atmospheres with high relative humidity or disposed or by shallow land burial under unsaturated, but still humid....... A model of the quantitative aspects for the equilibrium situation is presented. Experiments with hygroscopic water uptake support the model and give indications about the rate of the process. The release mechanism is only thought to be important for radionuclides which are not fixed in a low...

  19. Stabilization of ZnCl2-Containing Waste Using Calcium Sulfoaluminate Cement

    International Nuclear Information System (INIS)

    Cau Dit Coumes, C.; Berger, S.; Le Bescop, P.; Damidot, D.

    2013-01-01

    The potential of calcium sulfoaluminate (CSA) cement was investigated to solidify and stabilize radwastes containing large amounts of soluble zinc chloride (a strong inhibitor of Portland cement hydration). Hydration of pastes and mortars prepared with a 0.5 mol/L ZnCl 2 mixing solution was characterized over one year as a function of the gypsum content of the binder and the thermal history of the material. Blending the CSA clinker with 20% gypsum enabled rapid hydration, with only very small delay compared with a reference prepared with pure water. It also improved the compressive strength of the hardened material and significantly reduced its expansion under wet curing. Moreover, the hydrate assemblage was less affected by a thermal treatment at early age simulating the temperature rise and fall occurring in a large-volume drum of cemented waste. Fully hydrated materials contained ettringite, amorphous aluminum hydroxide, straetlingite, together with AFm phases (Kuzel's salt associated with monosulfoaluminate or Friedel's salt depending on the gypsum content of the binder), and possibly C-(A)-S-H. Zinc was readily insolubilized and could not be detected in the pore solution extracted from cement pastes, or in their leachates after 3 months of leaching by pure water at pH 7. The good retention of zinc by the cement matrix was mainly attributed to the precipitation of a hydrated and well crystallized phase with platelet morphology (which may belong to the layered double hydroxides family) at early age ≤ 1 day), and to chemisorption onto aluminum hydroxide at later age. (author)

  20. Test of 134Cs, 85,89Sr leaching rate in a resemble vitrifiable cement waste form

    International Nuclear Information System (INIS)

    Lin Meiqiong; Wei Feng; Yin Qi; Fan Xianhua; Xu Shengli; Li Yongde

    2003-01-01

    A novel material--resemble vitrifiable cement for conditioning low and mediate level radioactive waste has been developed. Waste form has been characterized for their physical and chemical performance, phase composition. The cement formulation has been patented. In this experiment the cement is mixed with simulated wastes spiked with 134 Cs and 85,89 Sr by 5 min at least. The Ratio of the waste to the cement is 0.45-0.55. The mixture is packed into cylindrical molds which has the same dimension of diameter and height . The grouts are cured for a period of 28 d in a room temperature curing chamber at an atmospheric pressure. The cured waste form is then completely immersed into deionized water. According to standard GB7023-86, leaching rate of 134 Cs and 85,89 Sr are measured. The result shows that the leaching rate of the species 134 Cs and 85,89 Sr is to be on the order 10 -4 and 10 -5 on the 42 d immersion, respectively and is better than that of commercial cement

  1. Waste-form development for conversion to portland cement at Los Alamos National Laboratory (LANL) Technical Area 55 (TA-55)

    International Nuclear Information System (INIS)

    Veazey, G.W.; Schake, A.R.; Shalek, P.D.; Romero, D.A.; Smith, C.A.

    1996-10-01

    The process used at TA-55 to cement transuranic (TRU) waste has experienced several problems with the gypsum-based cement currently being used. Specifically, the waste form could not reliably pass the Waste Isolation Pilot Plant (WIPP) prohibition for free liquid and the Environmental Protection Agency (EPA)-Toxicity Characteristic Leaching Procedure (TCLP) standard for chromium. This report describes the project to develop a portland cement-based waste form that ensures compliance to these standards, as well as other performance standards consisting of homogeneous mixing, moderate hydration temperature, timely initial set, and structural durability. Testing was conducted using the two most common waste streams requiring cementation as of February 1994, lean residue (LR)- and oxalate filtrate (OX)-based evaporator bottoms (EV). A formulation with a pH of 10.3 to 12.1 and a minimum cement-to-liquid (C/L) ratio of 0.80 kg/l for OX-based EV and 0.94 kg/L for LR-based EV was found to pass the performance standards chosen for this project. The implementation of the portland process should result in a yearly cost savings for raw materials of approximately $27,000 over the gypsum process

  2. Study and development of methodologies for qualification of waste products in repositories according to international standards

    International Nuclear Information System (INIS)

    Seles, Sandro Rogerio Novaes; Tello, Cledola Cassia Oliveira de

    2005-01-01

    One of the processes to treat dangerous wastes is to immobilise them in cement. At CDTN/CNEN some researches are carried out on cementation in order to establish process parameters, materials, and equipment, aiming at the safe disposal of these wastes, protecting of the human being and the environment of possible risks. To establish the compressive strength of cemented products is important because it implies in its suitability for handling, transportation and storage without risks for the human bodies or environment. It is urgent to obtain the certification of the compressive strength test providing reproducible, trustful and suitable results, mainly to assure its traceability. At Cementation Laboratory (LABCIM/CDTN) the certification process of the compressive strength was begun in the year 2000. It was completed the necessary adequacies, the staff training, and the first internal audit. It is previewed for the current year another internal audit, the external audit, and the certification request. (author)

  3. Mixed waste solidification testing on polymer and cement-based waste forms in support of Hanford's WRAP 2A facility

    International Nuclear Information System (INIS)

    Burbank, D.A. Jr.; Weingardt, K.M.

    1993-10-01

    A testing program has been conducted by the Westinghouse Hanford Company to confirm the baseline waste form selection for use in Waste Receiving and Processing (WRAP) Module 2A. WRAP Module 2A will provide treatment required to properly dispose of containerized contact-handled, mixed low-level waste at the US Department of Energy Hanford Site in south-central Washington State. Solidification/stabilization has been chosen as the appropriate treatment for this waste. This work is intended to test cement-based, thermosetting polymer, and thermoplastic polymer solidification media to substantiate the technology approach for WRAP Module 2A. Screening tests were performed using the major chemical constituent of each waste type to measure the gross compatibility with the immobilization media and to determine formulations for more detailed testing. Surrogate materials representing each of the eight waste types were prepared in the laboratory. These surrogates were then solidified with the selected immobilization media and subjected to a battery of standard performance tests. Detailed discussion of the laboratory work and results are contained in this report

  4. Development programs in the United States of America for the application of cement-based grouts in radioactive waste management

    Energy Technology Data Exchange (ETDEWEB)

    Dole, L.R.; Row, T.H.

    1984-01-01

    This paper briefly reviews seven cement-based waste form development programs at six of the US Department of Energy (DOE) sites. These sites have developed a variety of processes that range from producing 25 mm (1 in.) diameter pellets in a glove box to producing 240 m (800 ft.) diameter grout sheets within the bedding planes of a deep shale formation. These successful applications of cement-based waste forms to the many radioactive waste streams from nuclear facilities bear witness to the flexibility and reliability of this class of materials. This paper also discusses the major issues regarding the application of cement-based waste forms to radioactive waste management problems. These issues are (1) leachability, (2) radiation stability, (3) thermal stability, (4) phase complexity of the matrix, and (5) effects of the waste stream composition. A cursory review of current research in each of these areas is given This paper also discusses future trends in cement-based waste form development and applications. 31 references, 11 figures.

  5. Development programs in the United States of America for the application of cement-based grouts in radioactive waste management

    International Nuclear Information System (INIS)

    Dole, L.R.; Row, T.H.

    1984-01-01

    This paper briefly reviews seven cement-based waste form development programs at six of the US Department of Energy (DOE) sites. These sites have developed a variety of processes that range from producing 25 mm (1 in.) diameter pellets in a glove box to producing 240 m (800 ft.) diameter grout sheets within the bedding planes of a deep shale formation. These successful applications of cement-based waste forms to the many radioactive waste streams from nuclear facilities bear witness to the flexibility and reliability of this class of materials. This paper also discusses the major issues regarding the application of cement-based waste forms to radioactive waste management problems. These issues are (1) leachability, (2) radiation stability, (3) thermal stability, (4) phase complexity of the matrix, and (5) effects of the waste stream composition. A cursory review of current research in each of these areas is given This paper also discusses future trends in cement-based waste form development and applications. 31 references, 11 figures

  6. Increase in the amount of evaporator concentrate from nuclear power plants in cemented products

    International Nuclear Information System (INIS)

    Costa, Bruna S.; Tello, Clédola C.O.

    2017-01-01

    Nuclear power plants, research centers and other nuclear facilities are sources of radioactive liquid waste generation. These wastes can come from cooling of the primary reactor system, cleaning spent pool of fuel, washing contaminated clothing, among others. One of the most used methods for the treatment of these aqueous flows is the evaporation, which generates the concentrate of the evaporator, waste classified as low and medium level of radiation. Norms determine that radioactive waste must be minimized, and that to be accepted in repositories, they must be solidified. The work sought to reduce the volume of the evaporated concentrate waste and its subsequent solidification in cement. In order to carry out the tests, the evaporator concentrate (CE) simulation solution was prepared and then dried in an oven. Subsequently, cementation of the dry material was made using cement, fluidizer, NaOH and water. After a curing time of 28 days, the compressive strength tests were made for all specimens obtained, and for the samples that obtained resistance above that required by the norm, which is 10MPa, the percentages of reject incorporated and volume reduction. The results showed that, by drying the evaporator concentrate, it was possible to reduce the volume of the waste generated by up to 27% in relation to the waste without drying, which shows that drying is an effective way to increase the incorporation of the evaporator concentrate in packaged waste

  7. Effect of colloidal nano-silica on the mechanical and physical behaviour of waste-glass cement mortar

    International Nuclear Information System (INIS)

    Aly, M.; Hashmi, M.S.J.; Olabi, A.G.; Messeiry, M.; Abadir, E.F.; Hussain, A.I.

    2012-01-01

    Highlights: → Glass powder (GP) and nano-silica (CS) were used as a partial cement replacement in cement mortar (CM). → No damaging effect can be detected due to the reaction between GP and CM with particle size up to 75 μm. → Hybrid combination of GP/CS greatly improved mechanical properties and microstructure of CM. -- Abstract: This paper presents a laboratory study of the properties of colloidal nano-silica (CS)/waste glass cement composites. The microstructure, alkali-silica reaction (ASR), and the mechanical properties of cement mortars containing waste glass powder (WG) as a cement replacement with and without CS are investigated and compared with plain mortar. In addition, the hydration of cement compounds was followed by differential thermal analysis (DTA), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results show that incorporation of WG has a positive effect on the mechanical properties of cement mortars especially when CS is presented. In addition, the DTA/TGA results and XRD analysis show a reduction in the calcium hydroxide (CH) content in mortars with both WG and a hybrid combination of WG and CS. This confirms the improvement of mechanical properties and the occurrence of the pozzolanic reaction after 28 days of hydration.

  8. Physico-Chemical Studies Involving Incorporation of Radioactive and Industrial Waste In Cement-Epoxy Resin Matrix

    International Nuclear Information System (INIS)

    Sayed, M.S.; Hafez, N.

    1999-01-01

    Cement and epoxy resin as chemical additives are proposed to incorporate different types of wastes. The study was extended to prepare different mixtures of cement and epoxy resin in presence of some toxic ions. The studied ions were Cd II, Ni II, Cu II, Fe III, Ce IV, 154+152 Eu, phenol and toluene. The physical, mechanical and leaching properties of the mixtures were studied. The thermal analysis and infrared spectra were also investigated. It was observed that all the studied properties of the epoxy modified cement as a disposal matrix was improved

  9. Change of carcinogenic chrysotile fibers in the asbestos cement (eternit) to harmless waste by artificial carbonatization: Petrological and technological results

    Energy Technology Data Exchange (ETDEWEB)

    Radvanec, Martin; Tuček, Ľubomír; Derco, Ján; Čechovská, Katarína [State Geological Institute of Dionýz Štúr, Mlynská dolina 1, SK-817 04 Bratislava (Slovakia); Németh, Zoltán, E-mail: zoltan.nemeth@geology.sk [State Geological Institute of Dionýz Štúr, Mlynská dolina 1, SK-817 04 Bratislava (Slovakia)

    2013-05-15

    Highlights: ► Carcinogenic chrysotile fibers in asbestos cement (eternit) are liquidated. ► Thermally modified eternit grist (at 650 °C, 1 h) reacts with CO{sub 2} + water. ► Carbonates hydromagnesite and magnesite are the newly formed products of artificial carbonatization. ► Neutralizing of extreme pH values (around 12) at large eternit dumps. ► An alternative methodology for permanent liquidation of a part of CO{sub 2} emissions. -- Abstract: Asbestos cement materials, mainly the eternit roof ceiling, being widely applied in the past, represent a serious environmental load. The solar radiation, rain and frost cause the deliberation of cement from the eternit roofing and consequently the wind contaminates the surrounding area by the asbestos (chrysotile) fibers. In combination with other carcinogens (e.g. smoking), or at reduced immunity of a man, they may cause serious respiratory diseases and lung cancer. The article presents the procedure and experimental results of artificial carbonatization, applied in the asbestos cement (eternit). The wet crushed and pulverized asbestos cement was thermally modified at 650 °C and then the chrysotile fibers easily and completely reacted with the mixture of CO{sub 2} and water, producing new Mg-rich carbonates – hydromagnesite and magnesite: 2Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 3thermally} {sub modified} {sub chrysotile}+5CO{sub 2}+nH{sub 2}O→Mg{sub 5}(CO{sub 3}){sub 4}(OH){sub 2}⋅4H{sub 2}O{sub hydromagnesite}+MgCO{sub 3magnesite}+4SiO{sub 2} · nH{sub 2}O{sub in} a{sub morphous} {sub phase};n=3÷9 Applying this methodology, the asbestos-bearing waste can be stabilized and environmentally friendly permanently deposited. Finding a way of neutralizing of extreme pH values (around 12) at large eternit dumps represents also an asset of presented research. Simultaneously, the artificial carbonatization of chrysotile asbestos, applying CO{sub 2}, offers an alternative way for permanent liquidation of a part of

  10. Change of carcinogenic chrysotile fibers in the asbestos cement (eternit) to harmless waste by artificial carbonatization: Petrological and technological results

    International Nuclear Information System (INIS)

    Radvanec, Martin; Tuček, Ľubomír; Derco, Ján; Čechovská, Katarína; Németh, Zoltán

    2013-01-01

    Highlights: ► Carcinogenic chrysotile fibers in asbestos cement (eternit) are liquidated. ► Thermally modified eternit grist (at 650 °C, 1 h) reacts with CO 2 + water. ► Carbonates hydromagnesite and magnesite are the newly formed products of artificial carbonatization. ► Neutralizing of extreme pH values (around 12) at large eternit dumps. ► An alternative methodology for permanent liquidation of a part of CO 2 emissions. -- Abstract: Asbestos cement materials, mainly the eternit roof ceiling, being widely applied in the past, represent a serious environmental load. The solar radiation, rain and frost cause the deliberation of cement from the eternit roofing and consequently the wind contaminates the surrounding area by the asbestos (chrysotile) fibers. In combination with other carcinogens (e.g. smoking), or at reduced immunity of a man, they may cause serious respiratory diseases and lung cancer. The article presents the procedure and experimental results of artificial carbonatization, applied in the asbestos cement (eternit). The wet crushed and pulverized asbestos cement was thermally modified at 650 °C and then the chrysotile fibers easily and completely reacted with the mixture of CO 2 and water, producing new Mg-rich carbonates – hydromagnesite and magnesite: 2Mg 3 Si 2 O 5 (OH) 3thermally modified chrysotile +5CO 2 +nH 2 O→Mg 5 (CO 3 ) 4 (OH) 2 ⋅4H 2 O hydromagnesite +MgCO 3magnesite +4SiO 2 · nH 2 O in a morphous phase ;n=3÷9 Applying this methodology, the asbestos-bearing waste can be stabilized and environmentally friendly permanently deposited. Finding a way of neutralizing of extreme pH values (around 12) at large eternit dumps represents also an asset of presented research. Simultaneously, the artificial carbonatization of chrysotile asbestos, applying CO 2 , offers an alternative way for permanent liquidation of a part of industrial CO 2 emissions, contributing to multiple benefit of this methodology

  11. The long term effect on cement mortar by admixture of spray drying absorption products

    International Nuclear Information System (INIS)

    Jeppesen, K.G.

    1988-01-01

    Preliminary investigations have shown that the substitutions of up to 10% fly ash (FA), with spray drying absorption products (SDA), in cement mortars (cement: 80% rapid portland cement (RPC), 10-20% FA, 0-10% SDA) results in low early strength of the same magnitude as in mortar with 80% RPC + 20% FA. Use of the modified instructions for preparation of mortar prisms containing SDA resulted in satisfactory early strengths. A series of mortar prisms with increasing content of SDA (x% RPC, (100-x)% SDA in cements; 0 80% cannot be stored wet. The effects on mortars of the individual constituents of the SDA-products are studied by XRD, development in strength and density. Fragments of 2 year old SDA containing cement mortars and SDA containing concrete from a parking place have been studied

  12. 75 FR 453 - FLSMidth, Inc., Cement Division, Product Engineering, Including On-Site Leased Workers of Aerotek...

    Science.gov (United States)

    2010-01-05

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-72,048] FLSMidth, Inc., Cement..., Inc., Cement Division, Product Engineering, including on-site leased workers of Aerotek Contract.... were also employed on-site at FLSmidth, Inc., Cement Division, Product Engineering, Bethlehem...

  13. A preliminary evaluation of comminution and sampling strategies for radioactive cemented waste

    Energy Technology Data Exchange (ETDEWEB)

    Bilodeau, M.; Lastra, R.; Bouzoubaa, N. [Natural Resources Canada, Ottawa, ON (Canada); Chapman, M. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2011-07-01

    Lixiviation of Hg, U and Cs contaminants and micro-encapsulation of cemented radioactive waste (CRW) are the two main components of a CRW stabilization research project carried out at Natural Resources Canada in collaboration with Atomic Energy of Canada Limited. Unmolding CRW from the storage pail, its fragmentation into a size range suitable for both processes and the collection of a representative sample are three essential steps for providing optimal material conditions for the two studies. Separation of wires, metals and plastic incorporated into CRW samples is also required. A comminution and sampling strategy was developed to address all those needs. Dust emissions and other health and safety concerns were given full consideration. Surrogate cemented waste (SCW) was initially used for this comminution study where Cu was used as a substitute for U and Hg. SCW was characterized as a friable material through the measurement of the Bond work index of 7.7 kWh/t. A mineralogical investigation and the calibration of material heterogeneity parameters of the sampling error model showed that Cu, Hg and Cs are finely disseminated in the cement matrix. A sampling strategy was built from the model and successfully validated with radioactive waste. A larger than expected sampling error was observed with U due to the formation of large U solid phases, which were not observed with the Cu tracer. SCW samples were crushed and ground under different rock fragmentation mechanisms: compression (jaw and cone crushers, rod mill), impact (ball mill), attrition, high voltage disintegration and high pressure water (and liquid nitrogen) jetting. Cryogenic grinding was also tested with the attrition mill. Crushing and grinding technologies were assessed against criteria that were gathered from literature surveys, experiential know-how and discussion with the client and field experts. Water jetting and its liquid nitrogen variant were retained for pail cutting and waste unmolding while

  14. A preliminary evaluation of comminution and sampling strategies for radioactive cemented waste

    International Nuclear Information System (INIS)

    Bilodeau, M.; Lastra, R.; Bouzoubaa, N.; Chapman, M.

    2011-01-01

    Lixiviation of Hg, U and Cs contaminants and micro-encapsulation of cemented radioactive waste (CRW) are the two main components of a CRW stabilization research project carried out at Natural Resources Canada in collaboration with Atomic Energy of Canada Limited. Unmolding CRW from the storage pail, its fragmentation into a size range suitable for both processes and the collection of a representative sample are three essential steps for providing optimal material conditions for the two studies. Separation of wires, metals and plastic incorporated into CRW samples is also required. A comminution and sampling strategy was developed to address all those needs. Dust emissions and other health and safety concerns were given full consideration. Surrogate cemented waste (SCW) was initially used for this comminution study where Cu was used as a substitute for U and Hg. SCW was characterized as a friable material through the measurement of the Bond work index of 7.7 kWh/t. A mineralogical investigation and the calibration of material heterogeneity parameters of the sampling error model showed that Cu, Hg and Cs are finely disseminated in the cement matrix. A sampling strategy was built from the model and successfully validated with radioactive waste. A larger than expected sampling error was observed with U due to the formation of large U solid phases, which were not observed with the Cu tracer. SCW samples were crushed and ground under different rock fragmentation mechanisms: compression (jaw and cone crushers, rod mill), impact (ball mill), attrition, high voltage disintegration and high pressure water (and liquid nitrogen) jetting. Cryogenic grinding was also tested with the attrition mill. Crushing and grinding technologies were assessed against criteria that were gathered from literature surveys, experiential know-how and discussion with the client and field experts. Water jetting and its liquid nitrogen variant were retained for pail cutting and waste unmolding while

  15. Study on the mechanisms of solidification for Cs+ and Sr2+ in alkali-activated slag cement waste forms

    International Nuclear Information System (INIS)

    Yan Sheng; Shen Xiaodong; Lu Linchao; Wu Xuequan; Wen Yinghui

    1994-09-01

    The mechanisms of adsorption and chemical immobilization in Alkali-Activated Slag Cement (AASC) waste forms were quantitatively studied for Cs + and Sr 2+ . Experimental results show that, hardened AASC paste with zeolite and silica fume possesses strong adsorption ability and anti-desorption ability for Cs + and Sr 2+ . The results and analyzed by XRD show that CS + and SR 2+ could be incorporated into the lattice of C-S-H by replacing Ca 2+ in C-S-H. The d 111 values of C-S-H increase with increasing CsNO 3 and Sr(NO 3 ) 2 dosages in a limited and regular step. After washed out by deionized water in a ultrasonic washer, samples were analyzed by SEM-EDS and a lot of Cs + and Sr 2+ were detected. This means that the hydration products of AASC have a high retaining ability for Cs + and Sr 2+ . (3 tabs., 8 figs.)

  16. High-performance cement-based grouts for use in a nuclear waste disposal facility

    International Nuclear Information System (INIS)

    Onofrei, M.; Gray, M.N.

    1992-12-01

    National and international agencies have identified cement-based materials as prime candidates for sealing vaults that would isolate nuclear fuel wastes from the biosphere. Insufficient information is currently available to allow a reasonable analysis of the long-term performance of these sealing materials in a vault. A combined laboratory and modelling research program was undertaken to provide the necessary information for a specially developed high-performance cement grout. The results indicate that acceptable performance is likely for at least thousands of years and probably for much longer periods. The materials, which have been proven to be effective in field applications, are shown to be virtually impermeable and highly leach resistant under vault conditions. Special plasticizing additives used in the material formulation enhance the physical characteristics of the grout without detriment to its chemical durability. Neither modelling nor laboratory testing have yet provided a definitive assessment of the grout's longevity. However, none of the results of these studies has contraindicated the use of high-performance cement-based grouts in vault sealing applications. (Author) (24 figs., 6 tabs., 21 refs.)

  17. PERFORMANCE OF CEMENT MORTARS REPLACED BY GROUND WASTE BRICK IN DIFFERENT AGGRESSIVE CONDITIONS

    Directory of Open Access Journals (Sweden)

    ILHAMI DEMIR

    2011-09-01

    Full Text Available This article investigates the sulphate resistance of cement mortars when subjected to different exposure conditions. Cement mortars were prepared using ground waste brick (GWB as a pozzolanic partial replacement for cement at replacement levels of 0%, 2.5%, 5%, 7.5, 10%, 12.5 and 15%. Mortar specimens were stored under three different conditions: continuous curing in lime-saturated tab water (TW, continuous exposure to 5% sodium sulphate solution (SS, and continuous exposure to 5% ammonium nitrate solution (AN, at a temperature of 20 ± 3 ºC, for 7, 28, 90, and 180 days. Prisms with dimensions of 25×25×285 mm, to determine the expansions of the mortar samples; and another set of prisms with dimensions of 40×40×160 mm, were prepared to calculate the compressive strength of the samples. It was determined that the GWB replacement ratios between 2.5% and 10% decreased the 180 days expansion values. The highest compressive strength values were found for the samples with 10% replacement ratio in the TW, SS, and AN conditions for 180 days. The microstructure of the mortars were investigated using scanning electron microscopy (SEM and the Energy dispersive X-ray (EDX.

  18. Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility

    International Nuclear Information System (INIS)

    Ko, Chia-Ling; Chen, Jian-Chih; Hung, Chun-Cheng; Wang, Jen-Chyan; Tien, Yin-Chun; Chen, Wen-Cheng

    2014-01-01

    In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30 MPa after 24 h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution. - Highlights: • Bone cement precursor with nanocrystals is characterized. • DCP-rich CPCs with nanocrystals exhibited biphasic product phases. • Nanocrystals in cement significantly affected the interlocking ability. • Nanocrystals in cement exhibited higher strength and anti-dispersion. • DCP-rich CPCs increase the potential of bioresorption after reaction

  19. Utilization of Iron Ore Tailings as Raw Material for Portland Cement Clinker Production

    Directory of Open Access Journals (Sweden)

    Li Luo

    2016-01-01

    Full Text Available The cement industry has for some time been seeking alternative raw material for the Portland cement clinker production. The aim of this research was to investigate the possibility of utilizing iron ore tailings (IOT to replace clay as alumina-silicate raw material for the production of Portland cement clinker. For this purpose, two kinds of clinkers were prepared: one was prepared by IOT; the other was prepared by clay as a reference. The reactivity and burnability of raw meal, mineralogical composition and physical properties of clinker, and hydration characteristic of cement were studied by burnability analysis, differential thermal analysis, X-ray diffraction, and hydration analysis. The results showed that the raw meal containing IOT had higher reactivity and burnability than the raw meal containing clay, and the use of IOT did not affect the formation of characteristic mineralogical phases of Portland cement clinker. Furthermore, the physical and mechanical performance of two cement clinkers were similar. In addition, the use of IOT was found to improve the grindability of clinker and lower the hydration heat of Portland cement. These findings suggest that IOT can replace the clay as alumina-silicate raw material for the preparation of Portland cement clinker.

  20. CONSTRUCTION MATERIALS FROM WASTE PRODUCTS

    Directory of Open Access Journals (Sweden)

    Тахира Далиевна Сидикова

    2016-02-01

    Full Text Available We have studied the physical and chemical processes occurring during the thermal treatment of ceramic masses on the basis of compositions of natural raw materials and waste processing facilities. The study of structures of ceramic samples species has shown different types of crystalline phases.The results have shown that the waste of Kaytashsky tungsten-molybdenum ores (KVMR may be used as the main raw material to develop new compositions for ceramic materials. The optimal compositions of ceramic tiles for the masses and technological parameters of obtaining sintered materials based on the compositions of kaolin fireclay KVMR have been developed.It has been found that the use of the waste of Kaytashskoy tungsten-molybdenum ore (KVMR in the composition of the ceramic material will expand the raw material base of ceramic production, reduce the roasting temperature and the cost of ceramic materials and products.

  1. Radiolysis in cement-based materials ; application to radioactive waste-forms

    International Nuclear Information System (INIS)

    Bouniol, P.

    2014-01-01

    Cement-based materials appear to be an original environment with respect to radiolysis, due to their intrinsic complexity (porous, multiphasic and evolutional medium) or their very specific physico-chemical conditions (hyper-alkaline medium with pH ≥ 13, high content in calcium) or by the fact of numerous couplings existing between different phenomenologies. At the level of a radioactive cemented wasteform, a high degree of complexity is reached, in particular if the system communicates with the atmosphere (open system allowing regulation of the pressures but also the admission of O 2 , strong reactive with regards to radiolysis). Then, the radiolysis description exceeds widely the only one aspect of the decomposition of alkaline water under irradiation and makes necessary a global phenomenological approach. In this context, some 'outlying' phenomena, highly coupled with radiation chemistry, have to be taken into account because they contribute to deeply modify the net result of the radiolysis: radioactive decay of multiple αβγ emitters with filiation, phase changes (for example H 2 aq → H 2 gas) within the pores, gas transport by convection (Darcy law) and by diffusion (Fick law), precipitation/dissolution of solid phases, effect of the ionic strength and the temperature, disturbances connected to the presence of some solutes with redox potentialities (iron, sulphur). The integration work carried out on the previous points leads to an operational model (DOREMI) allowing the estimate of H 2 amounts produced by radiolysis in different cemented radioactive waste-forms. As the final expression of the model, numerical simulations constitute a relevant tool of expertise and prospecting, contributing to accompany the thought on radiolysis in cement matrices in general and in cemented waste-forms in particular. Starting from different examples, simulations can be so used in order to test some hypotheses or illustrate the greatest influence of gas transport, dose

  2. Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement

    International Nuclear Information System (INIS)

    Aubert, J.E.; Husson, B.; Sarramone, N.

    2006-01-01

    This paper is the first of a series of two articles dealing with the processes applied to MSWI fly ash with a view to reusing it safely in cement-based materials. Part 1 presents two stabilization processes and Part 2 deals with the use of the two treated fly ashes (TFA) in mortars. Two types of binder were used: an Ordinary Portland Cement (OPC) containing more than 95% clinker (CEM I 52.5R) and a binary blend cement composed of 70% ground granulated blast furnace slag and 30% clinker (CEM III-B 42.5N). In this first part, two stabilization processes are presented: the conventional process, called 'A', based on the washing, phosphation and calcination of the ash, and a modified process, called 'B', intended to eliminate metallic aluminum and sulfate contained in the ash. The physical, chemical and mineralogical characteristics of the two TFA were comparable. The main differences observed were those expected, i.e. TFA-B was free of metallic aluminum and sulfate. The mineralogical characterization of the two TFAs highlighted the presence of large amounts of a calcium aluminosilicate phase taking two forms, a crystalline form (gehlenite) and an amorphous form. Hydration studies on pastes containing mixed TFA and calcium hydroxide showed that this phase reacted with calcium hydroxide to form calcium aluminate hydrates. This formation of hydrates was accompanied by a hardening of the pastes. These results are very encouraging for the reuse of such TFA in cement-based materials because they can be considered as pozzolanic additions and could advantageously replace a part of the cement in cement-based materials. Finally, leaching tests were carried out to evaluate the environmental impact of the two TFAs. The elements which were less efficiently stabilized by process A were zinc, cadmium and antimony but, when the results of the leaching tests were compared with the thresholds of the European landfill directive, TFA-A could nevertheless be accepted at landfills for non

  3. Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, J.E. [Laboratoire Materiaux et Durabilite des Constructions (L.M.D.C.), INSA-UPS, 135 avenue de Rangueil, 31077 Toulouse cedex 4 (France)]. E-mail: aubert@insa-toulouse.fr; Husson, B. [Laboratoire Materiaux et Durabilite des Constructions (L.M.D.C.), INSA-UPS, 135 avenue de Rangueil, 31077 Toulouse cedex 4 (France); Sarramone, N. [Laboratoire Materiaux et Durabilite des Constructions (L.M.D.C.), INSA-UPS, 135 avenue de Rangueil, 31077 Toulouse cedex 4 (France)

    2006-08-25

    This paper is the first of a series of two articles dealing with the processes applied to MSWI fly ash with a view to reusing it safely in cement-based materials. Part 1 presents two stabilization processes and Part 2 deals with the use of the two treated fly ashes (TFA) in mortars. Two types of binder were used: an Ordinary Portland Cement (OPC) containing more than 95% clinker (CEM I 52.5R) and a binary blend cement composed of 70% ground granulated blast furnace slag and 30% clinker (CEM III-B 42.5N). In this first part, two stabilization processes are presented: the conventional process, called 'A', based on the washing, phosphation and calcination of the ash, and a modified process, called 'B', intended to eliminate metallic aluminum and sulfate contained in the ash. The physical, chemical and mineralogical characteristics of the two TFA were comparable. The main differences observed were those expected, i.e. TFA-B was free of metallic aluminum and sulfate. The mineralogical characterization of the two TFAs highlighted the presence of large amounts of a calcium aluminosilicate phase taking two forms, a crystalline form (gehlenite) and an amorphous form. Hydration studies on pastes containing mixed TFA and calcium hydroxide showed that this phase reacted with calcium hydroxide to form calcium aluminate hydrates. This formation of hydrates was accompanied by a hardening of the pastes. These results are very encouraging for the reuse of such TFA in cement-based materials because they can be considered as pozzolanic additions and could advantageously replace a part of the cement in cement-based materials. Finally, leaching tests were carried out to evaluate the environmental impact of the two TFAs. The elements which were less efficiently stabilized by process A were zinc, cadmium and antimony but, when the results of the leaching tests were compared with the thresholds of the European landfill directive, TFA-A could nevertheless be accepted at

  4. Immobilization of low and intermediate level radioactive liquid wastes using some industrial by-product materials

    International Nuclear Information System (INIS)

    Sami, N.M.; EI-Dessouky, M.I.; Abou EI-Nour, F.H.; Abdel-Khalik, M.

    2006-01-01

    Immobilization of low and intermediate level.radioactive liquid wastes in different matrices: ordinary Portland cement and cement mixed with some industrial byproduct: by-pass kiln cement dust, blast furnace slag and ceramic sludge was studied. The effect of these industrial by-product materials on the compressive strength, water immersion, radiation effect and teachability were investigated. The obtained results showed that, these industrial by-product improve the cement pastes where they increase the compressive strength, decrease the leaching rate for radioactive cesium-137 and cobalt-60 ions through the solidified waste forms and increase resistance for y-radiation. It is found that, solidified waste forms of intermediate level liquid waste (ILLW) had high compressive strength values more than those obtained from low level liquid waste (LLLW). The compressive strength increased after immersion in different leachant for one and three months for samples with LLLW higher than those obtained for ILLW. The cumulative fractions released of cesium-137 and cobalt-60 of solidified waste forms of LLLW was lower than those obtained for ILLW

  5. The incorporation of wood waste ash as a partial cement replacement material for making structural grade concrete: An overview

    Directory of Open Access Journals (Sweden)

    Swaptik Chowdhury

    2015-06-01

    Full Text Available With increasing industrialization, the industrial byproducts (wastes are being accumulated to a large extent, leading to environmental and economic concerns related to their disposal (land filling. Wood ash is the residue produced from the incineration of wood and its products (chips, saw dust, bark for power generation or other uses. Cement is an energy extensive industrial commodity and leads to the emission of a vast amount of greenhouse gases, forcing researchers to look for an alternative, such as a sustainable building practice. This paper presents an overview of the work and studies done on the incorporation of wood ash as partial replacement of cement in concrete from the year 1991 to 2012. The aspects of wood ash such as its physical, chemical, mineralogical and elemental characteristics as well as the influence of wood ash on properties such as workability, water absorption, compressive strength, flexural rigidity test, split tensile test, bulk density, chloride permeability, freeze thaw and acid resistance of concrete have been discussed in detail.

  6. Leachability of radionuclides from cement solidified waste forms produced at operating nuclear power plants

    International Nuclear Information System (INIS)

    Croney, S.T.

    1985-03-01

    This study determined the leachability indexes of radionuclides contained in solidified liquid wastes from operating nuclear power plants. Different sizes of samples of cement-solidified liquid wastes were collected from two nuclear power plants - a pressurized water reactor and a boiling water reactor - to correlate radionuclide leaching from small- and full-sized (55-gallon) waste forms. Diffusion-based model analysis (ANS 16.1) of measured radionuclide leach data from both small- and full-sized samples was performed and indicate that leach data from small samples can be used to determine leachability indexes for full-sizes waste forms. The leachability indexes for cesium, strontium, and cobalt isotopes were determined for waste samples from both plants according to the models used for ANS 16.1. The leachability indexes for the pressurized water reactor samples were 6.4 for cesium, 7.1 for strontium, and 10.4 for cobalt. Leachability indexes for the boiling water reactor samples were 6.5 for cesium, 8.6 for strontium, and 11.1 for cobalt

  7. Physical chemistry of portland-cement hydrate, radioactive-waste hosts: Final report, January 16, 1987--December 31, 1987

    International Nuclear Information System (INIS)

    Grutzeck, M.W.

    1989-01-01

    This is a final report summarizing the results of a study of the physical and crystal chemistry of potential hydroxylated radioactive waste hosts compatible with portland cement. Research has focussed on the identification and evaluation of hydrated host phases for four ions: cesium, strontium, iodine and boron. These ions were chosen because they are among the most long lived of the radioactive waste ions as well as the most difficult to immobilize with cement-based materials. Results show that such phases do indeed exist, and that they are excellent host phases for the above ions

  8. Manufacturing of concrete with residues from iron ore exploitation using the technology of radioactive waste cementation

    Energy Technology Data Exchange (ETDEWEB)

    Versieux, Juniara L.; Lameiras, Fernando S.; Tello, Cledola Cassia Oliveira de, E-mail: juniarani@gmail.com, E-mail: fsl@cdtn.br, E-mail: tellocc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nucelar (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    Radioactive wastes from various segments of economy are immobilized by cementation, because of availability and widespread use in civil construction of cement. New cementitious materials are developed in CDTN using mining residues based on cementing techniques of radioactive wastes. Special procedures were developed to obtain concrete with the use of super plasticizers in which natural sand was totally replaced by mining residues. The motivation for this research is the exploration of banded iron formations (BIF) as iron ore in 'Quadrilatero Ferrifero' of Minas Gerais, where huge amounts of residues are generated with great concern about the environmental sustainability and safety of dams for residue storage. The exploitation of river sand causes many negative impacts, which leads to interest in its replacement by another raw material in mortar and concrete manufacturing. The use of BIF mining residues were studied for manufacturing of concrete pavers to contribute to reducing the impact caused by extraction of natural sand and use of mining residues. Previously developed procedures with total replacement of natural sand for mining residues were modified, including use of gravel to obtain pavers with improved properties. Four different mixtures were tested, in which the proportion of gravel and super plasticizer was varied. Monitored properties of pavers, among others, were compression resistance, water absorption, and void volume. With addition of gravel, the pavers had higher void index than those made only with mortar, and higher resistance to compression after 28 days of curing (an average of 18MPa of those made with mortar to 24MPa of those made with concrete). (author)

  9. Manufacturing of concrete with residues from iron ore exploitation using the technology of radioactive waste cementation

    International Nuclear Information System (INIS)

    Versieux, Juniara L.; Lameiras, Fernando S.; Tello, Cledola Cassia Oliveira de

    2015-01-01

    Radioactive wastes from various segments of economy are immobilized by cementation, because of availability and widespread use in civil construction of cement. New cementitious materials are developed in CDTN using mining residues based on cementing techniques of radioactive wastes. Special procedures were developed to obtain concrete with the use of super plasticizers in which natural sand was totally replaced by mining residues. The motivation for this research is the exploration of banded iron formations (BIF) as iron ore in 'Quadrilatero Ferrifero' of Minas Gerais, where huge amounts of residues are generated with great concern about the environmental sustainability and safety of dams for residue storage. The exploitation of river sand causes many negative impacts, which leads to interest in its replacement by another raw material in mortar and concrete manufacturing. The use of BIF mining residues were studied for manufacturing of concrete pavers to contribute to reducing the impact caused by extraction of natural sand and use of mining residues. Previously developed procedures with total replacement of natural sand for mining residues were modified, including use of gravel to obtain pavers with improved properties. Four different mixtures were tested, in which the proportion of gravel and super plasticizer was varied. Monitored properties of pavers, among others, were compression resistance, water absorption, and void volume. With addition of gravel, the pavers had higher void index than those made only with mortar, and higher resistance to compression after 28 days of curing (an average of 18MPa of those made with mortar to 24MPa of those made with concrete). (author)

  10. Pore solution chemistry of simulated low-level liquid waste incorporated in cement grouts

    International Nuclear Information System (INIS)

    Kruger, A.A.

    1995-12-01

    Expressed pore solutions from simulated low level liquid waste cement grouts cured at room temperature, 50 degree C and 90 degree C for various duration were analyzed by standard chemical methods and ion chromatography. The solid portions of the grouts were formulated with portland cement, fly ash, slag, and attapulgite clay in the ratios of 3:3:3:1. Two different solutions simulating off-gas condensates expected from vitrification of Hanford low level tank wastes were made. One is highly alkaline and contains the species Na + , P0 4 3- , N0 2 - , NO 3 - and OH - . The other is carbonated and contains the species, Na + , PO 4 3- , NO 2 - , NO 3 - , and CO 3 2- . In both cases phosphate rapidly disappeared from the pore solution, leaving behind sodium in the form of hydroxide. The carbonates were also removed from the pore solution to form calcium carbonate and possibly calcium monocarboaluminate. These reactions resulted in the increase of hydroxide ion concentration in the early period. Subsequently there was a significant reduction OH - and Na + ion concentrations. In contrast high concentration of N0 2 - and N0 3 - were retained in the pore solution indefinitely

  11. Development of Magnesium Silicate Hydrate cement system for nuclear waste encapsulation

    International Nuclear Information System (INIS)

    Zhang, T.; Vandeperre, L.J.; Cheeseman, C.R.

    2012-01-01

    A novel low pH cement system for encapsulating nuclear industry wastes containing aluminium has been developed using blends of MgO and silica fume (SF). Identification of the hydrated phases in MgO/silica fume samples showed that brucite formed in early stages of hydration and then reacted with the silica fume to produce a magnesium silicate hydrate (M-S-H) gel phase. When all brucite reacts with silica fume a cement system with an equilibrium pH just below 10 was achieved. Selected mixes have been characterized for hydration reactions, setting time and strength development. Mortar samples with w/s ratios of 0.5 and 50% by weight of sand added achieved compressive strengths in excess of 95 MPa after 28 days. The addition of MgCO 3 buffered the early pH and the addition of fine sand particles eliminated shrinkage cracking. The interaction of the optimised mortar with Al metal has been investigated. Al metal strips were firmly bound into the MgO:SF:sand samples and no H 2 gas detected, and this indicates that the novel systems developed in this work have potential for encapsulating certain types of problematic legacy wastes from the nuclear industry. (authors)

  12. Physical, chemical and mineralogical characterization of water treatment plant waste for use in soil-cement brick; Caracterizacao fisica, quimica e mineralogica de residuo de estacao de tratamento de aguas para aproveitamento em tijolo solo-cimento

    Energy Technology Data Exchange (ETDEWEB)

    Pessin, L.R.; Destefani, A.Z.; Holanda, J.N.F., E-mail: larapessin@hotmail.com [Universidade Estadual do Norte Fluminense Darcy Ribeiro (CCT/PPGECM/UENF), Campos dos Goytacazes, RJ (Brazil)

    2011-07-01

    The water treatment plants (WTP) for human consumption generate huge amounts of waste in the form of sludge (sludge) that have been over the years mostly inadequately prepared in water resources and the environment. Moreover, traditional methods of disposal of waste water treatment plants commonly used are generally costly activities. An alternative method for disposal of this waste abundant is its incorporation in ceramic products. This work is focused on the physical-chemical and mineralogical composition of a sample of waste water treatment plants from the region of Campos dos Goytacazes-RJ to their use in the manufacture of soil-cement brick. Several characterization techniques were used including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, picnometry, particle size analysis and plasticity. The experimental results indicate that the waste water treatment plants have the potential to be used in the manufacture of ecologic soil-cement bricks. (author)

  13. Leach testing of simulated ion-exchange resin waste solidified in cement

    International Nuclear Information System (INIS)

    Muurinen, A.K.; Uotila, P.I.; Ovaskainen, R.M.

    Leach tests were carried out on ion-exchange resins solidified in cement. Three product mixtures, two isotopes and four leachants at two temperatures, were tested. The increase of resin content increased the leaching of Cs-137; the effect of silix admixture was negligible. The type of the leachant has a stronger influence on Co-60 than on Cs-137. The increase of temperature usually also increased leaching. (author)

  14. A Review of Partial Replacement of Cement with some Agro Wastes

    African Journals Online (AJOL)

    user

    INTRODUCTION. The high cost of cement, ... Research on alternative to cement, has so far centred on the partial ... MATERIALS AND METHODS .... 2 : Compound Composition of Acha Husk Ash (AHA) Mixed with Cement(C). Using. Bogue's ...

  15. The Long-Term Study of Some mechanical and Chemical Properties of Polymer Modified Cement Waste Forms

    International Nuclear Information System (INIS)

    Shatta, H.A.; Eskander, S.B.

    2002-01-01

    The present work is a new experimental trend to study the long-term durability of polymer/cement/borate waste forms in storage and disposal sites during the long period of time. The data obtained indicate that all the samples of polymer modified cement waste forms immersed in both distilled and ground water (for more than 2700 days) show a slight increase in the compressive strength values. The chemical stability of the immobilized borate waste forms in distilled and ground water was studied. The cumulative leach fraction in percentage, of Cs-137 isotope from the final solidified waste forms in case of using ground water was lower than that in distilled water for all samples used and the presence of polymer lowered the percent release of radioactive Cs-137 isotope in all samples studied . The leach coefficients (Lc) and the leach indices (Li) of radioactive cesium-137 isotope for cement borate and polymer modified cement waste forms were also calculated. It was found that the leach indices values greater than 6

  16. Organic Rankine cycle saves energy and reduces gas emissions for cement production

    International Nuclear Information System (INIS)

    Wang, Huarong; Xu, Jinliang; Yang, Xufei; Miao, Zheng; Yu, Chao

    2015-01-01

    We investigated ORCs (organic Rankine cycles) integrated with typical China cement production line. The dry air at the kiln cooler outlet with the temperature of 220 °C was the waste heat. The fluids of hexane, isohexane, R601, R123 and R245fa were selected for ORCs based on the critical temperature criterion. The developed ORC verified the thermodynamics analysis. The NPV (net present value) and PBP (payback period) methods were applied to evaluate the economic performance. The LCA (life cycle assessment) was applied to evaluate the environment impacts. ORCs could generate 67,85,540–81,21,650 kWh electricity per year, equivalent to save 2035–2436 tons standard coal and reduce 7743–9268 tons CO 2 emission, for a 4000 t/d cement production line. ORCs reduced gas emissions of CO 2 by 0.62–0.74%, SO 2 by 3.83–4.59% and NO x by 1.36–1.63%. The PBP (payback period) was 2.74–3.42 years. The ORCs had the reduction ratios of EIL (environment impact load) by 1.49–1.83%, GWP (global warming potential) by 0.74–0.92%, AP (acidification potential) by 2.34–2.84%, EP (eutrophication potential) by 0.96–1.22% and HTP (human toxicity potential) by 2.38–2.89%. The ORC with R601 as the fluid had the best economic performance and significant gas emission reductions. ORCs had good economic performance and reduce the gas emissions. - Highlights: • Organic Rankine Cycles were integrated with the cement production line. • Five organic fluids were used as the working fluids for ORCs. • Thermal, economic and gas emission performances were analyzed. • R601 was the best fluid for ORC with the heat source temperature of 220 °C. • ORCs had good economic and gas emission reduction performances

  17. Synthesis of knowledge on the long-term behaviour of concretes. Applications to cemented waste packages

    International Nuclear Information System (INIS)

    Richet, C.; Galle, C.; Le Bescop, P.; Peycelon, H.; Bejaoui, S.; Tovena, I.; Pointeau, I.; L'Hostis, V.; Levera, P.

    2004-03-01

    As stipulated in the former law of December 91 relating to 'concrete waste package', a progress report (phenomenological reference document) was first provided in 1999. The objective was to make an assessment of the knowledge acquired on the long-term behaviour of cement-based waste packages in the context of deep disposal and/or interim storage. The present document is an updated summary report. It takes into account a new knowledge assessment, considers coupled mechanisms and should contribute to the first performance studies (operational calculations). Handling and radio-nuclides (RN) confinement are the two major functional properties requested from the concrete used for the waste packages. In unsaturated environment (interim storage/disposal prior to closing), the main problem is the generation of cracks in the material. This aspect is a key parameter from the mechanical point of view (retrievability). It can have a major impact on the disposal phase (confinement). In saturated environment (disposal post-closing phase), the main concern is the chemical degradation of the waste package concrete submitted to underground waters leaching. In this context, the major thema are: the durability of the concretes under water (chemical degradation) and in unsaturated medium (corrosion of reinforcement), matter transport, RN retention, chemistry / transport / mechanical couplings. On the other hand, laboratory data on the behaviour of concretes are used to evaluate the RN source term of waste packages in function of time (concrete waste package OPerational Model, i.e. 'Concrete MOP'). The 'MOP' provides the physico-chemical description of the RN release in relationship with the waste package degradation itself. This description is based on simplified phenomenology for which only dimensioning mechanisms are taken into account. The use of Diffu-Ca code (basic module for the MOP) on the CASTEM numerical plate-form, already allows operational predictions. (authors)

  18. Effect of Graphene Oxide (GO on the Morphology and Microstructure of Cement Hydration Products

    Directory of Open Access Journals (Sweden)

    Liguo Wang

    2017-12-01

    Full Text Available In this study, the effects of graphene oxide (GO on the microstructure of cement mortars were studied using scanning electron microscopy (SEM, thermogravimetric (TG, and X-ray diffraction (XRD techniques. Cement mortar samples with different proportions of GO (0.02, 0.04, 0.06, and 0.08 wt % based on the weight of cement were prepared. The test results showed that GO affected the crystallization of cement hydration products, C–S–H (calcium silicate hydrate is the main hydrate product and CH (calcium hydroxide. The morphology of hydration products changed with the increase of GO content. Furthermore, the results of XRD analyses showed that the diffraction peak intensity and the crystal grain size of CH (001, (100, (101, and (102 for GO samples increased considerably compared with the control sample. Based on the results, it can be understood that GO can modify the crystal surface of CH, leading to the formation of larger crystals.

  19. Development of low-pH cements for immobilisation of intermediate level radioactive waste: achievements and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Martins de Freitas, Regeane; Al-Tabbaa, Abir [Engineering Department, University of Cambridge, Cambridge (United Kingdom)

    2013-07-01

    Although cementation is a widely recognized solidification/ stabilization process for immobilisation of Intermediate Level Radioactive Waste (ILRW), the low resistance to hyper-alkaline pore waters compromises the effectiveness of the process when Portland Cement (PC) is employed. Moreover the manufacture of PC is responsible for significant CO{sub 2} emissions. In this context, low pH cements are environmentally more suitable and have emerged as a potential alternative for obtaining secure waste forms. This paper summarises the achievements on development of low-pH cements and the challenges of using these new materials for the ILRW immobilisation. The performance of waste forms is also discussed in terms of radionuclides release. Reactive magnesium oxide and magnesium phosphate cements are emphasised as they feature important advantages such as consumption of available constituents for controlling acid-base reactions, reduced permeability and higher density. Additionally, in order to identify new opportunities for study, the long-term modelling approach is also briefly discussed. (authors)

  20. 75 FR 4423 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Portland Cement...

    Science.gov (United States)

    2010-01-27

    ... Production Act of 1993--Portland Cement Association Notice is hereby given that, on December 14, 2009... seq. (``the Act''), Portland Cement Association (``PCA'') has filed written notifications... Cement, Hannibal, MO has been added as a party to this venture. Also, the following parties have...

  1. 77 FR 5573 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Portland Cement...

    Science.gov (United States)

    2012-02-03

    ... Production Act of 1993--Portland Cement Association Notice is hereby given that, on January 6, 2012, pursuant... seq. (``the Act''), Portland Cement Association (``PCA'') has filed written notifications..., Newark, DE, has been added as a party to this venture. Also, Texas-Lehigh Cement Company, Buda, TX...

  2. 76 FR 12370 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Portland Cement...

    Science.gov (United States)

    2011-03-07

    ... Production Act of 1993--Portland Cement Association Notice is hereby given that, on February 02, 2011... seq. (``the Act''), Portland Cement Association (``PCA'') has filed written notifications..., Praxair, Danbury, CT; Metso Minerals, York, PA; Lehigh Cement Company LLC, Allentown, PA; Lehigh Northwest...

  3. 76 FR 34252 - Notice Pursuant to the National Cooperative Research and Production Act of 1993; Portland Cement...

    Science.gov (United States)

    2011-06-13

    ... Production Act of 1993; Portland Cement Association Notice is hereby given that, on May 12, 2011, pursuant to.... (``the Act''), Portland Cement Association (``PCA'') has filed written notifications simultaneously with... plaintiffs to actual damages under specified circumstances. Specifically, Drake Cement, LLC, Scottsdale, AZ...

  4. Feed Materials Production Center Waste Management Plan

    International Nuclear Information System (INIS)

    Watts, R.E.; Allen, T.; Castle, S.A.; Hopper, J.P.; Oelrich, R.L.

    1986-01-01

    In the process of producing uranium metal products used in Department of Energy (DOE) defense programs at other DOE facilities, various types of wastes are generated at the Feed Materials Production Center (FMPC). Process wastes, both generated and stored, are discussed in the Waste Management Plan and include low-level radioactive waste (LLW), mixed hazardous/radioactive waste, and sanitary/industrial waste. Scrap metal waste and wastes requiring special remediation are also addressed in the Plan. The Waste Management Plan identifies the comprehensive programs developed to address safe storage and disposition of all wastes from past, present, and future operations at the FMPC. Waste streams discussed in this Plan are representative of the waste generated and waste types that concern worker and public health and safety. Budgets and schedules for implementation of waste disposition are also addressed. The waste streams receiving the largest amount of funding include LLW approved for shipment by DOE/ORO to the Nevada Test Site (NTS) (MgF 2 , slag leach filter cake, and neutralized raffinate); remedial action wastes (waste pits, K-65 silo waste); thorium; scrap metal (contaminated and noncontaminated ferrous and copper scrap); construction rubble and soil generated from decontamination and decommissioning of outdated facilities; and low-level wastes that will be handled through the Low-Level Waste Processing and Shipping System (LLWPSS). Waste Management milestones are also provided. The Waste Management Plan is divided into eight major sections: Introduction; Site Waste and Waste Generating Process; Strategy; Projects and Operations; Waste Stream Budgets; Milestones; Quality Assurance for Waste Management; and Environmental Monitoring Program

  5. Product Evaluation Task Force Phase Two report for BWR/PWR dissolver wastes

    International Nuclear Information System (INIS)

    Francis, A.J.

    1990-01-01

    It has been proposed that all Intermediate Level Wastes arising at Sellafield should be encapsulated prior to ultimate disposal. The Product Evaluation Task Force (PETF) was set up to investigate possible encapsulants and to produce an adequate data base to justify the preferred matrices. This report details the work carried out, under Phase 2 of the Product Evaluation Task Force programme, on BWR/PWR Dissolver Wastes. Three possible types of encapsulants for BWR/PWR Dissolver Wastes:- Inorganic cements, Polymer cements and Polymers are evaluated using the Kepner Tregoe decision analysis technique. This technique provides a methodology for scoring and ranking alternative options and evaluating any risks associated with an option. The analysis shows that for all four stages of waste management operations ie Storage, Transport, handling and emplacement, Disposal and Process, cement matrices are considerably superior to other potential matrices. A matrix, consisting of three parts Blast Furnace Slag (BFS) to one part Ordinary Portland Cement (OPC), is recommended for Phase 3 studies on BWR/PWR Dissolver Wastes. (author)

  6. Studies of the setting behavior of cement suspensions

    International Nuclear Information System (INIS)

    Rudolph, G.; Luo, S.; Vejmelka, P.; Koester, R.

    1983-10-01

    The design of process for cementation of radioactive waste solutions is determined not only by the quality of the final product but also by the behavior of the cement grout before and during setting. For these reasons quantitative investigations were performed on the characteristics of the cement suspensions considered for solidification of intermediate-level liquid wastes which are composed mainly of cement, bentonite, simulated waste solution, and water. Particular interest was given to the differences in behavior of the various types of cement. The parameters investigated include viscosity, bleeding, volume change during setting, influence of compacting by vibration, time of setting, heat of hydration. At the end of the report the merits and drawbacks of the different cements are tabulated. These data may serve as a decision aid in selecting an appropriate type of cement

  7. Energy conservation and dust production in wet rotary cement kilns

    Energy Technology Data Exchange (ETDEWEB)

    Sell, N J; Fischbach, F A

    1976-12-01

    Energy conservation is currently a major concern of the cement industry. A comparison of data supplied by the U.S. Federal Energy Administration with that gathered in an extensive private study incorporating 29 wet cement plants indicates that a significant reduction of the energy consumed can be accomplished by decreasing the amount of dust generated in the process. Energy saving of 8 percent through dust suppression appears possible by increasing the slurry moisture and by using hammermills rather than impactors as the crushing technique.

  8. Application of solvlent change techniques to blended cements used to immobilize low-level radioactive liquid waste

    International Nuclear Information System (INIS)

    Kruger, A.A.

    1996-07-01

    The microstructures of hardened portland and blended cement pastes, including those being considered for use in immobilizing hazardous wastes, have a complex pore structure that changes with time. In solvent exchange, the pore structure is examined by immersing a saturated sample in a large volume of solvent that is miscible with the pore fluid. This paper reports the results of solvent replacement measurements on several blended cements mixed at a solution:solids ratio of 1.0 with alkaline solutions from the simulation of the off- gas treatment system in a vitrification facility treating low-level radioactive liquid wastes. The results show that these samples have a lower permeability than ordinary portland cement samples mixed at a water:solids ratio of 0.70, despite having a higher volume of porosity. The microstructure is changed by these alkaline solutions, and these changes have important consequences with regard to durability

  9. LL/ILW: Post-Qualification of Old Waste through Non-Destructive Extraction of Barrels from Cement Shields - 13535

    International Nuclear Information System (INIS)

    Oehmigen, Steffen; Ambos, Frank

    2013-01-01

    Currently there is a large number of radioactive waste drums entombed in cement shields at German nuclear power plants. These concrete containers used in the past for the waste are not approved for the final repository. Compliance with current acceptance criteria of the final repository has to be proven by qualification measures on the waste. To meet these criteria, a new declaration and new packing is necessary. A simple non-destructive extraction of about 2000 drums from their concrete shields is not possible. So different methods were tested to find a way of non-destructive extraction of old waste drums from cement shields and therefore reduce the final repository volume and final repository costs by using a container accepted and approved for Konrad. The main objective was to build a mobile system to offer this service to nuclear plant stations. (authors)

  10. Properties of the cements and their use in the storage systems of low-level radioactive wastes

    International Nuclear Information System (INIS)

    Almazan T, M. G.

    2011-11-01

    The use of materials containing cement has generalized in the facilities of definitive storage of radioactive wastes due to their easy handling and availability. Besides conforming the buildings and structures, these materials are part of the barriers system that will maintain the isolated radioactive wastes of the biosphere until their activity has decayed at innocuous levels. However, to fulfill this function, the effectiveness and durability of these materials should be demonstrated fully. In Mexico the intention exists of building a definitive storehouse for the low-level radioactive wastes, however are few the studies on the behavior of the materials containing cement used in this type of facilities. With the purpose of to guide and promoting the study of the national cements, in this work is made a revision of the characteristics and properties of the cements with relationship to its use in the systems of definitive storage of low-level radioactive wastes, as well as of some studies that are realized to evaluate its acting as engineering barriers. (Author)

  11. Experimental study on the leaching of radioactive materials from radioactive wastes solidified in cement into sea water. Part 2

    International Nuclear Information System (INIS)

    Hatta, H.; Ono, H.; Nagakura, T.; Machida, T.; Seki, T.; Maki, Y.

    Results are presented from the study on leachability of 60 Co and 137 Cs from BWR concentrated wastes that had been solidified in cement. The leachability of 60 Co is very small compared to that of 137 Cs and varies greatly with the type of leaching medium. The effect of duration of immersion on leachability is comparatively large

  12. Integration of oxygen membranes for oxygen production in cement plants

    DEFF Research Database (Denmark)

    Puig Arnavat, Maria; Søgaard, Martin; Hjuler, Klaus

    2015-01-01

    The present paper describes the integration of oxygen membranes in cement plants both from an energy, exergy and economic point of view. Different configurations for oxygen enrichment of the tertiary air for combustion in the pre-calciner and full oxy-fuel combustion in both pre-calciner and kiln...

  13. The improved heat integration of cement production under limited process conditions: A case study for Croatia

    International Nuclear Information System (INIS)

    Boldyryev, Stanislav; Mikulčić, Hrvoje; Mohorović, Zoran; Vujanović, Milan; Krajačić, Goran; Duić, Neven

    2016-01-01

    Given that cement is the most widely used material for housing and modern infrastructure needs, this paper analyses the energy efficiency of the cement manufacturing processes for a particular cement plant. The cement industry is one of the largest consumers of carbon-containing primary energy sources and one of the primary polluters of the environment, emitting approximately 5% of global pollution. Energy consumption represents the largest part of the production cost for cement factories and has a significant influence on product prices. Given that it is realised in modern society that infrastructural projects lead to a higher level of economy and sustainability for countries, reducing the production cost in the cement industry is a very important problem. The authors analysed the energy consumption of a particular cement factory in Croatia to determine the minimum energy targets of production and proposed pathways to improve energy efficiency. The Process Integration approach was used in this study. Nevertheless, the features of the cement factory forced the research to update its methodological steps to propose real pathways for a retrofit project with the aim of achieving the optimal minimum temperature difference between process streams. There are various streams, including those that contain solid particles, gas and air streams, and streams, that should be cooled down rapidly; these facts become more complicated by the special construction of the process equipment, which causes heat transfer between some streams to be impossible. The main objective of this paper is to determine the potential of real energy savings and propose a solution for a new concept of heat exchanger network (HEN) that avoids the process traps and provides a feasible retrofit. The maximum heat recovery of that production of a particular type of cement was determined and improved when a HEN was built. The authors conclude that the energy consumption of the cement factory can be reduced by

  14. Thermal properties of fly ash substituted slag cement waste forms for disposal of Savannah River Plant salt waste

    International Nuclear Information System (INIS)

    Roy, D.M.; Kaushal, S.; Licastro, P.H.; Langton, C.A.

    1985-01-01

    Waste processing at the Savannah River Plant will involve reconstitution of the salts (NaNO 3 , NaNO 2 , NaOH, etc.) into a concentrated solution (32 weight percent salts) followed by solidification in a cement-based waste form for burial. The stability and mechanical durability of such a 'saltstone monolith' will depend largely on the temperature reached due to heat of hydration and the thermal properties of the waste form. Fly ash has been used as an inexpensive constituent and to moderate the hydration and setting processes so as to avoid reaching prohibitively high temperatures which could cause thermal stresses. Both high-calcium and low-calcium fly ashes have been studied for this purpose. Other constituents of these mixes include granulated blast furnace slag and finely crushed limestone. Adiabatic temperature increase and thermal conductivity of these mixes have been studied and related x-ray diffraction and scanning electron microscopy studies carried out to understand the hydration process

  15. The chemistry of blended cements and backfills intended for use in radioactive waste disposal

    International Nuclear Information System (INIS)

    Glasser, F.; Tyrer, M.; Quillin, K.

    1999-01-01

    This project was initiated by Her Majesty's Inspectorate of Pollution (HMIP) at the time when UK NIREX had announced its intention to develop a repository for low and intermediate level nuclear waste in the vicinity of Sellafield. In this repository setting, two main barriers existed to the return of radio-isotopes to the biosphere: the natural, or geologic and hydrogeologic barriers, and the man-made barriers. These latter comprise relatively short-lived containers as well as an engineered backfill. The backfill was designed to condition a high pH in the repository, thereby lowering the solubility of many long-lived radionuclides yet not confine gases, which might be generated from chemical and radioactive waste within the repository vault. The Environment Agency for England and Wales had already taken independent steps to examine the suitability of alkaline backfills, based on Portland cement, limestone flour and Ca(OH) 2 , for the man-made barriers. Preliminary data on post-closure repository performance assessment at Sellafield suggested the importance of two additional factors which had not hitherto been considered in assessments: (i) temperature: Inclusion of heat generating waste could drive temperatures up to ∼80 deg. C in the post closure phase; (ii) salinity of deep groundwater: Much previous work has been done in initially-pure water but borehole analyses indicated high salinity at depth. Other potential deep repositories could also be saline. These impacts were likely to occur together throughout much of the post-closure phase: backfills were likely to be in prolonged contact with hot, saline groundwater. Previous studies demonstrated that cements achieve their performance by a sacrificial action. It is however essential that the cementitious materials should not dissolve too rapidly if prolonged backfill performance lifetimes are to be achieved. By dissolving cement backfills condition permeating water to a high pH and thereby lower the solubilities

  16. Performance of Cement Containing Laterite as Supplementary Cementing Material

    Directory of Open Access Journals (Sweden)

    Abbas Bukhari, Z. S.

    2013-03-01

    Full Text Available The utilization of different industrial waste, by-products or other materials such as ground granulated blast furnace slag, silica fume, fly ash, limestone, and kiln dust, etc. as supplemen- tary cementing materials has received considerable attention in recent years. A study has been conducted to look into the performance of laterite as Supplementary Cementing Materials (SCM. The study focuses on compressive strength performance of blended cement containing different percentage of laterite. The cement is replaced accordingly with percentage of 2 %, 5 %, 7 % and 10 % by weight. In addition, the effect of use of three chemically different laterites have been studied on physical performance of cement as in setting time, Le-Chatlier expansion, loss on ignition, insoluble residue, free lime and specifically compressive strength of cement cubes tested at the age of 3, 7, and 28 days. The results show that the strength of cement blended with laterite as SCM is enhanced. Key words: Portland cement, supplementary cementing materials (SCM, laterite, compressive strength KUI – 6/2013 Received January 4, 2012 Accepted February 11, 2013

  17. The application of waste fly ash and construction-waste in cement filling material in goaf

    Science.gov (United States)

    Chen, W. X.; Xiao, F. K.; Guan, X. H.; Cheng, Y.; Shi, X. P.; Liu, S. M.; Wang, W. W.

    2018-01-01

    As the process of urbanization accelerated, resulting in a large number of abandoned fly ash and construction waste, which have occupied the farmland and polluted the environment. In this paper, a large number of construction waste and abandoned fly ash are mixed into the filling material in goaf, the best formula of the filling material which containing a large amount of abandoned fly ash and construction waste is obtained, and the performance of the filling material is analyzed. The experimental results show that the cost of filling material is very low while the performance is very good, which have a good prospect in goaf.

  18. Valorisation of waste ilmenite mud in the manufacture of sulphur polymer cement.

    Science.gov (United States)

    Contreras, Manuel; Gázquez, Manuel Jesús; García-Díaz, Irene; Alguacil, Francisco J; López, Félix A; Bolívar, Juan Pedro

    2013-10-15

    This paper reports the preparation of sulphur polymer cements (SPCs) incorporating waste ilmenite mud for use in concrete construction works. The ilmenite mud raw material and the mud-containing SPCs (IMC-SPCs) were characterised physico-chemically and radiologically. The optimal IMC-SPC mixture had a sulphur/mud ratio (w/w) of 1.05 (mud dose 20 wt%); this cement showed the greatest compressive strength (64 MPa) and the lowest water absorption coefficient (0.4 g cm(-2) at 28 days). Since ilmenite mud is enriched in natural radionuclides, such as radium isotopes (2.0·10(3) Bq kg(-1)(228)Ra and 5.0·10(2) Bq kg(-1)(226)Ra), the IMC-SPCs were subjected to leaching experiments, which showed their environmental impact to be negligible. The activity concentration indices for the different radionuclides in the IMC-SPCs containing 10% and 20% ilmenite mud met the demands of international standards for materials used in the construction of non-residential buildings. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Ecological indices of manufacture of Portland cement clinker and production of the dolomite clinker

    Directory of Open Access Journals (Sweden)

    Vinnichenko Varvara

    2017-01-01

    Full Text Available It is shown that the production of dolomite clinker in comparison with that of Portland cement is environmentally appropriate. When calcining dolomite for cementitious binder, the pollution of the atmosphere by carbon dioxide is reduced due to its isolation during decarbonization reactions of calcium carbonates. Reducing fuel consumption for clinker burning provides less carbon dioxide emissions from combustion products. Reducing the firing temperature creates obstacles to the formation of nitrogen oxides. The production of binders from dolomite in comparison with the production of Portland cement helps to protect the environment from contamination

  20. Mobile calcination and cementation unit for solidification of concentrated radioactive wastes

    International Nuclear Information System (INIS)

    Napravnik, J.; Sazavsky, P.; Skaba, V.; Skvarenina, R.; Ditl, P.

    1985-01-01

    Mobile experimental unit MESA-1 was developed and manufactured for processing radioactive concentrates by direct cementation. The unit is mainly designed for processing low-level liquid wastes from nuclear power plants and other nuclear installations, in which the level of radioactivity does not exceed 10 10 Bq/m 3 , the salt content of liquid solutions does not exceed 500 kg/m 3 and the maximum amount of boric acid is 130 kg/m 3 . The equipment is built into three modules which may be assembled and dismantled in a short time and transported separately. The unit without the calciner module was tested in non-radioactive mode and in operation with actual radioactive wastes from the V-1 nuclear power plant. The course and results of the tests are described in detail. All project design values were achieved, a total of 18 dm 3 model solutions were processed and 1 m 3 of actual wastes with a salt content of 450 kg/m 3 . The test showed that with regard to the radiation level reached it will be necessary in the process of calcination to increase the shielding of certain exposed points. The calciner module is being assembled for completion. (Z.M.)

  1. A review of literature relevant to gas production in radioactive waste

    International Nuclear Information System (INIS)

    Norris, G.H.

    1987-11-01

    A review of relevant recent papers on gas generation in low-level wastes and intermediate-level wastes is presented. Chemical, microbiological, radiolytic and thermal reactions are considered for both unconditioned wastes and wastes conditioned in cement, or bitumen, or polymer. Possible reaction mechanisms are identified and the effects of temperature and pressure are evaluated. Estimations of the production of combustible gases (which also have the potential to form explosive mixtures) have been taken from the literature. The implications of gas production for pressurisation (and possible rupture) of waste drums and of a repository are assessed. Waste-treatment schemes for the reduction of gas-generation capacity of several waste-types are highlighted. Recommendations for further work are summarised. (author)

  2. Crumb waste tire rubber surface modification by plasma polymerization of ethanol and its application on oil-well cement

    Science.gov (United States)

    Xiaowei, Cheng; Sheng, Huang; Xiaoyang, Guo; Wenhui, Duan

    2017-07-01

    Crumb waste tire rubber (WTR) was pretreated by oxygen low temperature plasma (LTP) and modified by LTP polymerization process of ethanol monomer to improve the adhesion property with oil-well cement matrix and the mechanical properties of cement. The surface properties of modified crumb WTR and the mechanical properties and structures of modified oil-well cement were investigated by means of contact angle measurement, dispersion test, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), mechanics performance tests, permeability test and scanning electron microscopy (SEM). It was demonstrated that LTP treatment changed both the surface composition and roughness. The contact angle of pretreated crumb WTR dramatically fell from 122° to 34°, and sample with ethanol LPT polymer film decreased even further to 11°. The ATR-FTIR and XPS analysis results demonstrated that hydrophilic groups, such as -COOH, C-OH, and -CHO, were introduced on the WTR surface. The oxygen atomic percent increased from 8.11% to 14.50% and 24.83%. The mechanical properties, porosity and permeability of raw cement were compared to samples modified by untreated crumb WTR, pretreated crumb WTR and ethanol LTP polymerization treated crumb WTR. It was found that after 28 days, the compressive strength of the samples with the untreated crumb WTR decreased to 80% with respect to raw cement. The tensile strength and flexural strength also had a slight reduction compared with the raw cement. On the contrary, after 28 days, the tensile strength of cement modified by LTP polymerization treated WTR increased 11.03% and 13.36%, and the flexural strength increased 9.65% and 7.31%, respectively. A decrease in the compressive strength also occurred but was inconspicuous. A tight interface bonding for ethanol LTP polymerization treated WTR with cement matrix was observed via an SEM image.

  3. Cr