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Sample records for cement kiln dust

  1. Effect of kiln dust from a cement factory on growth of Vicia faba L.

    Science.gov (United States)

    Uysal, Ismet; Ozdilek, Hasan Göksel; Oztürk, Münir

    2012-04-01

    This study was undertaken to study the effects of different amounts of kiln dust mixed with soil on the seed germination, plant growth, leaf area and water content of Vicia faba cv. Eresen. The reason for this was that cement kiln dust generated as a by-product from the cement factories is rich in potassium, sulfate and other compounds. This product becomes a serious problem when it comes in contact with water. The dust was collected from a cement factory located in Canakkale. Various elements such as Al, Co, Mo, Ca, B, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Se and Zn were determined both in soil as well as kiln dust. Kiln dust was mixed with soil in pots (20 cm diameter) to make seven different treatments varying from 15 to 105 g kiln dust kg(-1) of soil. The experiment lasted for 4 months. Seeds of V faba were sown in the pots filled with mixtures of preanalysed kiln dust and soil. Germination was high in the pots with a lower treatment of cement kiln dust. However, lower germination rates were observed in the pots mixed with the highest and the medium amounts of cement kiln dust. Plants growing in the soil including 15 g kiln dust showed better performance in length as compared to control. Leaf area increased with increase in cement kiln dust content up to 60 g kiln dust kg(-1) of soil, but declined after 75 g kg(-1). Water content of leaves (mg cm(-2) leaf area) was found to be constantly decreasing with respect to increasing cement kiln content in the pots. Differences between the averages were evaluated by Tukey test and results were found to be significant.

  2. AIR POLLUTION CONTROL THROUGH KILN RECYCLING BY-PASS DUST IN A CEMENT FACTORY

    Directory of Open Access Journals (Sweden)

    F. Mohsenzadeh, J. Nouri, A. Ranjbar, M. Mohammadian Fazli, A. A. Babaie

    2006-01-01

    Full Text Available Air pollution is a major problem in the industrial areas. Cement dust is one of the important environmental pollutants. In this study the possibility of dust recycling especially kiln dust which has significant importance regarding air pollution in the cement plant, was examined. Tehran cement factory is one of the most important Iranian factories which is located in Tehran. This factory produces high volume of pollutants that are released to in environment. The possibility of reusing of kiln by pass returned dust has been examined in this factory. Different percentages of kiln by-pass dust of this factory were added to products and outcomes of its presence in parameters such as chemical compound, granulation, primary and final catch time, volume expansion, consumed water and resistance of mortar were surveyed. The result indicated that by adding the amounts of 3-8 dust the mortar resistance increase, but adding more than 15%, the mortar resistance has been decreased. Survey in consumed water proved that adding dust to cement, the trend for consuming water is decreased. After dust addition dust, primary and final catch time were compared in different samples and data which showed decrease in dust added samples. Cements with dust added showed increase in auto clave expansion. Overally, results proved that, the best percentage rate of dust addition to the cement was 15%.

  3. Characteristics of Portland blast-furnace slag cement containing cement kiln dust and active silica

    Directory of Open Access Journals (Sweden)

    A. Abdel Rahman

    2016-09-01

    Full Text Available This investigation dealt with the effect of active silica, silica fume (SF or rice husk ash (RHA, on the mechanical and physico-chemical characteristics of the hardened blended cement pastes made of Portland blast-furnace slag cement (PSC containing cement kiln dust (CKD cured under normal conditions. Two blends made of PSC and CKD, improved by SF and two blends made of PSC and CKD improved by RHA were investigated. Hardened blended cement pastes were prepared from each cement blend by using water/cement ratio (W/C of 0.30 by weight and hydrated for various curing ages of 1, 3, 7, 28 and 90 days at the normal curing conditions under tap water at room temperature. Each cement paste was tested for its physico-chemical and mechanical characteristics; these characteristics include: compressive strength and kinetics of hydration. The phase composition of the formed hydration products was identified using X-ray diffraction (XRD and differential thermal analysis (DTA. It was found that the partial substitution of PSC by 10% and 15% of CKD is associated with an increase in the rate of hydration and a subsequent improvement of compressive strength of hardened PSC–CKD pastes. In addition, the replacement of PSC, in PSC–CKD blends, by 5% active silica was accompanied by further improvement of the physico-mechanical characteristics of the hardened PSC–CKD pastes.

  4. Hydrothermal Characteristics of Blended Cement Pastes Containing Silica Sand Using Cement Kiln Dust as an Activator

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The hydrothermal reactivity of silica sand was studied using cement kiln dust (CKD) as an activator in addition to the Portlandcement fraction of El-Karnak cement (a blend of ordinary Portland cement and ground sand). Autoclaved El-Karnak cementpastes were studied at pressures of 0.507, 1.013 and 1.520 MPa of saturated steam with respect to their compressive strength,kinetics of hydrothermal reaction and the phase composition of the formed hydrates. The role of CKD in affecting thephysicochemical and mechanical properties of El-Karnak cement pastes was studied by autoclaving of several pastes containing5, 7.5, 10 and 20% CKD at a pressure of 1.013 MPa of saturated steam. CKD was added either as a raw CKD (unwashed) orafter washing with water (washed CKD). The results of these physicochemical studies obtained could be related as much aspossible to the role of CKD (raw or washed) in affecting the hydrothermal reactivity of silica sand in El-Karnak cement pastes.

  5. Lime kiln dust as a potential raw material in portland cement manufacturing

    Science.gov (United States)

    Miller, M. Michael; Callaghan, Robert M.

    2004-01-01

    In the United States, the manufacture of portland cement involves burning in a rotary kiln a finely ground proportional mix of raw materials. The raw material mix provides the required chemical combination of calcium, silicon, aluminum, iron, and small amounts of other ingredients. The majority of calcium is supplied in the form of calcium carbonate usually from limestone. Other sources including waste materials or byproducts from other industries can be used to supply calcium (or lime, CaO), provided they have sufficiently high CaO content, have low magnesia content (less than 5 percent), and are competitive with limestone in terms of cost and adequacy of supply. In the United States, the lime industry produces large amounts of lime kiln dust (LKD), which is collected by dust control systems. This LKD may be a supplemental source of calcium for cement plants, if the lime and cement plants are located near enough to each other to make the arrangement economical.

  6. Stabilization/solidification of selenium-impacted soils using Portland cement and cement kiln dust.

    Science.gov (United States)

    Moon, Deok Hyun; Grubb, Dennis G; Reilly, Trevor L

    2009-09-15

    Stabilization/solidification (S/S) processes were utilized to immobilize selenium (Se) as selenite (SeO(3)(2-)) and selenate (SeO(4)(2-)). Artificially contaminated soils were prepared by individually spiking kaolinite, montmorillonite and dredged material (DM; an organic silt) with 1000 mg/kg of each selenium compound. After mellowing for 7 days, the Se-impacted soils were each stabilized with 5, 10 and 15% Type I/II Portland cement (P) and cement kiln dust (C) and then were cured for 7 and 28 days. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effectiveness of the S/S treatments. At 28 days curing, P doses of 10 and 15% produced five out of six TCLP-Se(IV) concentrations below 10mg/L, whereas only the 15% C in DM had a TCLP-Se(IV) concentration phases for all three soil-cement slurries were calcium selenite hydrate (CaSeO(3).H(2)O) and selenate substituted ettringite (Ca(6)Al(2)(SeO(4))(3)(OH)(12).26H(2)O), respectively.

  7. Stabilization/solidification of selenium-impacted soils using Portland cement and cement kiln dust

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Deok Hyun, E-mail: dmoon10@hotmail.com [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Department of Environmental Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of); Grubb, Dennis G. [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Schnabel Engineering, LLC, 510 East Gay Street, West Chester, PA 19380 (United States); Reilly, Trevor L. [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

    2009-09-15

    Stabilization/solidification (S/S) processes were utilized to immobilize selenium (Se) as selenite (SeO{sub 3}{sup 2-}) and selenate (SeO{sub 4}{sup 2-}). Artificially contaminated soils were prepared by individually spiking kaolinite, montmorillonite and dredged material (DM; an organic silt) with 1000 mg/kg of each selenium compound. After mellowing for 7 days, the Se-impacted soils were each stabilized with 5, 10 and 15% Type I/II Portland cement (P) and cement kiln dust (C) and then were cured for 7 and 28 days. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effectiveness of the S/S treatments. At 28 days curing, P doses of 10 and 15% produced five out of six TCLP-Se(IV) concentrations below 10 mg/L, whereas only the 15% C in DM had a TCLP-Se(IV) concentration <10 mg/L. Several treatments satisfied the USEPA TCLP best demonstrated available technology (BDAT) limits (5.7 mg/L) for selenium at pozzolan doses up to 10 times less than the treatments that established the BDAT. Neither pozzolan was capable of reducing the TCLP-Se(VI) concentrations below 25 mg/L. Se-soil-cement slurries aged for 30 days enabled the identification of Se precipitates by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX). XRD and SEM-EDX analyses of the Se(IV)- and Se(VI)-soil-cement slurries revealed that the key selenium bearing phases for all three soil-cement slurries were calcium selenite hydrate (CaSeO{sub 3}.H{sub 2}O) and selenate substituted ettringite (Ca{sub 6}Al{sub 2}(SeO{sub 4}){sub 3}(OH){sub 12}.26H{sub 2}O), respectively.

  8. Characterization and utilization of cement kiln dusts (CKDs) as partial replacements of Portland cement

    Science.gov (United States)

    Khanna, Om Shervan

    The characteristics of cement kiln dusts (CKDs) and their effects as partial replacement of Portland Cement (PC) were studied in this research program. The cement industry is currently under pressure to reduce greenhouse gas (GHG) emissions and solid by-products in the form of CKDs. The use of CKDs in concrete has the potential to substantially reduce the environmental impact of their disposal and create significant cost and energy savings to the cement industry. Studies have shown that CKDs can be used as a partial substitute of PC in a range of 5--15%, by mass. Although the use of CKDs is promising, there is very little understanding of their effects in CKD-PC blends. Previous studies provide variable and often conflicting results. The reasons for the inconsistent results are not obvious due to a lack of material characterization data. The characteristics of a CKD must be well-defined in order to understand its potential impact in concrete. The materials used in this study were two different types of PC (normal and moderate sulfate resistant) and seven CKDs. The CKDs used in this study were selected to provide a representation of those available in North America from the three major types of cement manufacturing processes: wet, long-dry, and preheater/precalciner. The CKDs have a wide range of chemical and physical composition based on different raw material sources and technologies. Two fillers (limestone powder and quartz powder) were also used to compare their effects to that of CKDs at an equivalent replacement of PC. The first objective of this study was to conduct a comprehensive composition analysis of CKDs and compare their characteristics to PC. CKDs are unique materials that must be analyzed differently from PC for accurate chemical and physical analysis. The present study identifies the chemical and physical analytical methods that should be used for CKDs. The study also introduced a method to quantify the relative abundance of the different

  9. A New Kind of Eco-Cement Made of Cement Kiln Dust and Granular Blast Furnace Slag

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A research project was conducted to manufacture eco-cement for sustainable development using cement kiln dust( CKD ) and granular blast furnace slag( GBFS ).In the project, the burning process and mineral compositions of CKD clinker were investigated.Dife rent mineralizers such as CaSO4 and CaF2 , sulfur and alkali content were considered.The strength of CKD and GBFS eco-cement were evaluated.The results indicate the CKD clinker can not only form ordinary cement clinker minerals such as C3 S, C2 S and C4 AF, but also form strength to the Portland cement grade 32.5 when blend proportion is properly applied.

  10. Physicochemical and microbiological characterization of cement kiln dust for potential reuse in wastewater treatment.

    Science.gov (United States)

    Salem, W M; Sayed, W F; Halawy, S A; Elamary, R B

    2015-09-01

    Cement kiln dust (CKD), a byproduct of cement manufacturing process, was collected from Misr Cement Co. at Qena, Egypt. CKD was characterized by X-ray diffraction and FTIR analysis. This byproduct was investigated for its physical-chemical characters, antibacterial activities on sewage water and the presence of nematode, parasites and algae in the treated water. The efficiency of CKD-treated water was also examined on Hibiscus sabdarriffa seed germination. Total bacteria, total and fecal coliform, as well as fecal streptococci were completely inhibited by CKD. Interestingly, zinc, manganese, iron, nickel and lead were completely absent from sewage water as these metals precipitated after treatment with 10gl(-1) CKD. On the other hand, among all the tested plant criteria, only root length was significantly reduced by 55% and 15% after zero and 3 days of CKD addition respectively compared to control. Furthermore, plant lipid peroxidation showed no significant differences between treated sewage water and control after zero and 3 days time addition of CKD. Catalase enzyme activity showed significant decrease by 56% and 64%, while peroxidase activity significantly increased up to 49% and 63% compared to untreated sewage after zero and 3 days of treatment, respectively. The absorption of lead, iron and copper by treated and untreated plants showed no significant differences. Chromium ions were highly absorbed (0.075mgl(-1)) by plants irrigated only with treated sewage water at zero time, and decreased gradually to 0.018mgl(-1) after 3 days of CKD addition. This study highlighted the efficiency of cement kiln dust as an antibacterial agent and its ability of scavenging heavy metals leading to the use of treated sewage water in activities such as crop irrigation.

  11. Physicochemical characterization of cement kiln dust for potential reuse in acidic wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, A.; Boilard, S. [Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Building D, Room D215, Halifax, Nova Scotia, B3J 1Z1 (Canada); Walsh, M.E., E-mail: mwalsh2@dal.ca [Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Building D, Room D215, Halifax, Nova Scotia, B3J 1Z1 (Canada); Lake, C.B. [Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Building D, Room D215, Halifax, Nova Scotia, B3J 1Z1 (Canada)

    2010-01-15

    Cement kiln dust (CKD) is a fine-grained material produced during the manufacture of cement. Current reuse options are limited and the bulk of CKD not reused in the cement manufacturing process is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of CKD, it has the potential to be used as a replacement for lime in treating acidic wastewaters such as acid rock drainage (ARD). This paper outlines the results of an examination of the physical and chemical properties of CKD samples collected from six cement plants. The CKD samples were analyzed for major oxides using X-ray diffraction (XRD), available lime, specific surface area, particle size, and morphology using scanning electron microscope (SEM) and compared with a commercial quicklime product. Conductivity, pH, and calcium concentrations of slaked CKD and quicklime solutions were used as indicators of reactivity of the CKD. Slaking of two of the CKD samples with the highest free lime contents (e.g., 34 and 37% free CaO) gave elevated pH values statistically comparable to those of the commercial quicklime sample that was characterized as having 87% available CaO. Acid neutralization trials indicate that even CKD samples with low free lime contents could be effective at neutralizing acidic wastewaters.

  12. Physicochemical characterization of cement kiln dust for potential reuse in acidic wastewater treatment.

    Science.gov (United States)

    Mackie, A; Boilard, S; Walsh, M E; Lake, C B

    2010-01-15

    Cement kiln dust (CKD) is a fine-grained material produced during the manufacture of cement. Current reuse options are limited and the bulk of CKD not reused in the cement manufacturing process is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of CKD, it has the potential to be used as a replacement for lime in treating acidic wastewaters such as acid rock drainage (ARD). This paper outlines the results of an examination of the physical and chemical properties of CKD samples collected from six cement plants. The CKD samples were analyzed for major oxides using X-ray diffraction (XRD), available lime, specific surface area, particle size, and morphology using scanning electron microscope (SEM) and compared with a commercial quicklime product. Conductivity, pH, and calcium concentrations of slaked CKD and quicklime solutions were used as indicators of reactivity of the CKD. Slaking of two of the CKD samples with the highest free lime contents (e.g., 34 and 37% free CaO) gave elevated pH values statistically comparable to those of the commercial quicklime sample that was characterized as having 87% available CaO. Acid neutralization trials indicate that even CKD samples with low free lime contents could be effective at neutralizing acidic wastewaters.

  13. Phytoextraction of chloride from a cement kiln dust (CKD) contaminated landfill with Phragmites australis.

    Science.gov (United States)

    McSorley, Kaitlin; Rutter, Allison; Cumming, Robert; Zeeb, Barbara A

    2016-05-01

    Cement kiln dust (CKD) is a globally produced by-product from cement manufacturing that is stockpiled or landfilled. Elevated concentrations of chloride pose toxic threats to plants and aquatic communities, as the anion is highly mobile in water and can leach into surrounding water sources. Re-vegetation and in situ phytoextraction of chloride from a CKD landfill in Bath, ON, Canada, was investigated with the resident invasive species Phragmites australis (haplotype M). Existing stands of P. australis were transplanted from the perimeter of the site into the highest areas of contamination (5.9×10(3)μg/g). Accumulation in the shoots of P. australis was quantified over one growing season by collecting samples from the site on a bi-weekly basis and analyzing for chloride. Concentrations decreased significantly from early May (24±2.2×10(3)μg/g) until mid-June (15±2.5×10(3)μg/g), and then remained stable from June to August. Shoot chloride accumulation was not significantly affected by water level fluctuations at the site, however elevated potassium concentrations in the soil may have contributed to uptake. Based on shoot chloride accumulation and total biomass, it was determined that phytoextraction from the CKD landfill can remove 65±4kg/km(2) of chloride per season. Based on this extraction rate, removal of chloride present in the highly contaminated top 10cm of soil can be achieved in 3-9years. This is the first study to apply phytotechnologies at a CKD landfill, and to successfully demonstrate in situ phytoextraction of chloride.

  14. Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

    Directory of Open Access Journals (Sweden)

    Aly Ahmed

    2009-01-01

    Full Text Available An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD, a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

  15. Investigation into the use of cement kiln dust in high density sludge (HDS) treatment of acid mine water.

    Science.gov (United States)

    Mackie, Allison L; Walsh, Margaret E

    2015-11-15

    The purpose of this study was to investigate the potential to replace lime with cement kiln dust (CKD) in high density sludge (HDS) treatment of acid mine drainage (AMD). The bench-scale study used two water samples: AMD sampled from a lead-zinc mine with high concentrations of iron (Fe), zinc (Zn), and arsenic (As) (Fe/Zn-AMD) and a synthetic AMD solution (Syn-AMD) spiked with ferric sulfate (Fe2(SO4)3). Arsenic was found to be significantly reduced with CKD-HDS treatment of Fe/Zn-AMD compared to lime-HDS treatment, to concentrations below the stringent mine effluent discharge regulation of 0.10 mg As/L (i.e., 0.04 ± 0.02 mg/L). Both CKD- and lime-HDS treatment of the two AMD samples resulted in settled water Fe concentrations above the stringent discharge guideline of 0.3 mg Fe/L. CKD addition in the HDS process also resulted in high settled water turbidity, above typical discharge guidelines of 15 mg TSS/L. CKD-HDS treatment was found to result in significantly improved settled solids (i.e., sludge) quality compared to that generated in the lime-HDS process. HDS treatment with CKD resulted in 25-88% lower sludge volume indices, 2 to 9 times higher % wet solids, and 10 to 20 times higher % dry solids compared to lime addition. XRD and XPS testing indicated that CKD-HDS sludge consisted of mainly CaCO3 and SiO2 with Fe(3+) precipitates attached at particle surfaces. XRD and XPS testing of the lime-HDS generated sludge showed that it consisted of non-crystalline Fe oxides typical of sludge formed from precipitates with a high water concentration. Increased sedimentation rates were also found for CKD (1.3 cm/s) compared to lime (0.3 cm/s). The increased solids loading with CKD addition compared to lime addition in the HDS process was suggested to both promote surface complexation of metal precipitates with insoluble CKD particles and increase compression effects during Type IV sedimentation. These mechanisms collectively contributed to the reduced water content of

  16. Formation, release and control of dioxins in cement kilns.

    Science.gov (United States)

    Karstensen, Kåre Helge

    2008-01-01

    /precalciner kilns generally seems to have lower emissions than older wet-process cement kilns. It seems that the main factors stimulating formation of PCDD/PCDFs is the availability of organics in the raw material and the temperature of the air pollution control device. Feeding of materials containing elevated concentrations of organics as part of raw-material-mix should therefore be avoided and the exhaust gases should be cooled down quickly in long wet and long dry cement kilns without preheating. PCDD/PCDFs could be detected in all types of solid samples analysed: raw meal, pellets and slurry; alternative raw materials as sand, chalk and different ashes; cement kiln dust, clinker and cement. The concentrations are however generally low, similar to soil and sediment.

  17. 40 CFR 270.235 - Options for incinerators, cement kilns, lightweight aggregate kilns, solid fuel boilers, liquid...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Options for incinerators, cement kilns... Technology (MACT) Standards § 270.235 Options for incinerators, cement kilns, lightweight aggregate kilns... incinerator, cement kiln, lightweight aggregate kiln, solid fuel boiler, liquid fuel boiler, or...

  18. Simple Explanation on System Reform of Kiln Trail Dust Collector for 3000t/d Cement Production Line%浅谈3000t/d水泥生产线窑尾收尘系统改造

    Institute of Scientific and Technical Information of China (English)

    杨如顺; 吕忠明; 田源

    2012-01-01

      The paper presents the background, technical program, constructive program and engineering costs of system reform of kiln trail dust col ector for 3000t/d cement production line in Nanyang Hangtian Cement Plant. The fol owing program is:one similar bag dust col ector is paral el connected at the bag col ector with reversing blower and spun glass of high tempera-ture in original kiln trail, so as to increase the filtering area of kiln trail bag dust col ector and decrease the filtering wind speed. The reform shows an obvious result.%  介绍了南阳航天水泥厂3000t/d水泥生产线窑尾收尘系统的改造背景、技术方案、施工方案和工程造价。改造采用了在原窑尾反吹风高温玻纤袋收尘器旁并联一台同类型单排袋式收尘器的方案,以增大窑尾袋收尘器过滤面积和降低过滤风速。该窑尾收尘系统的改造取得了明显的成效。

  19. Dust extraction from gas in cement kilns, using bag filters; Depoussierage des gaz de four cimentier par les filtres a manches

    Energy Technology Data Exchange (ETDEWEB)

    Harmegnies, M. [CALCIA, 78 - Guerville (France). Direction Technique

    1996-12-31

    After a review of regulations concerning cement plant emissions, the two main cement production techniques (dry and semi-dry processes) are described and the electrostatic and bag filter de-dusting techniques are compared. Examples of pilot applications of these techniques in two French cement plants are presented and operating results (performances, transient procedures, costs) are discussed

  20. Spalling Resistant Bauxite Based Bricks for Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaohui; Peng Xigao

    2011-01-01

    @@ 1.Scope This standard specifies the term,definition,classification,labeling,technical requirements,test methods,inspection rules,packing,marking,transportation,storage,and quality certificate of spalling resistant bauxite based bricks for cement kiln.This standard is applicable to the spalling resistant bauxite based bricks for cement kiln.

  1. Static Model of Cement Rotary Kiln

    Directory of Open Access Journals (Sweden)

    Omar D. Hernández-Arboleda

    2013-11-01

    Full Text Available In this paper, a static model of cement rotary kilns is proposed. The system model is obtained through polynomial series. The proposed model is contrasted with data of a real plant, where optimal results are obtained. Expected results are measured with respect to the clinker production and the combustible consumption is measured in relation with the consumption calorific. The expected result of the approach is the increase of the profitability of the factory through the decrease of the consumption of the combustible.

  2. Effects of cement flue dusts from a Nigerian cement plant on air, water and planktonic quality.

    Science.gov (United States)

    Olaleye, Victor F; Oluyemi, Emmanuel A

    2010-03-01

    Effects of cement flue dust from Ewekoro cement Kilns were monitored at some aquatic receptor locations. High levels of total suspended particulates (TSPs) and atmospheric deposition rates (ADRs) were recorded within the factory compared to ancillary locations outside the factory. The TSP and ADR levels which were location dependent were significantly higher (P cement factory catchment areas.

  3. 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.

  4. 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...

  5. Modeling of Pulverized Coal Combustion in Cement Rotary Kiln

    OpenAIRE

    2006-01-01

    In this paper, based on analysis of the chemical and physical processes of clinker formation, a heat flux function was introduced to take account of the thermal effect of clinker formation. Combining the models of gas-solid flow, heat and mass transfer, and pulverized coal combustion, a set of mathematical models for a full-scale cement rotary kiln were established. In terms of commercial CFD code (FLUENT), the distributions of gas velocity, gas temperature, and gas components in a cement rot...

  6. ZrO2-Containing Refractories for Cement Rotary Kilns

    Institute of Scientific and Technical Information of China (English)

    YE Guotian; XU Yanqing

    2002-01-01

    ZrO2-containing refractories have been increasingly used for cement rotary kilns. This paper discusses how the properties and performance of ZrO2-containing. Refractories are inwroved in terms of chemical attack resistance, thermal shock resistance, thermal conductivity and mechanical stress.

  7. Composite Control of Precalciner Exit Temperature in Cement Rotary Kiln

    Institute of Scientific and Technical Information of China (English)

    赵晨; 诸静

    2003-01-01

    A composite control strategy for the precalciner exit temperature in cement kiln is introduced based on a mathematical model. In this model, the raw meal flow, coal powder flow and wind flow are taken as three input variables, the clinker fow and exit teperature of cement kiln are output variables, and other influencing factors are considered as disturbance. A composite control system is synthesied by integrating self-learning PID, fuzzy and feedforward function into a combined controller, and the arithmetics for the self-learning PID controller, fuzzy controller and feedforward controller are elaborated respectively. The control strategy has been realized by software in real practice at cement factory. Application results show that the composite control technology is superior to the general PID control in control effect, and is suitable to the industrial process control with slow parameter variation, nonlinearity and uncertainty.

  8. 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

    ... waste burning cement kilns that are effective until compliance with the standards under § 63.1220? 63... Operating Limits for Incinerators, Cement Kilns, and Lightweight Aggregate Kilns § 63.1204 What are the standards for hazardous waste burning cement kilns that are effective until compliance with the...

  9. Environmental impact assessment of combustible wastes utilization in rotary cement kilns

    OpenAIRE

    2013-01-01

    This study focuses on the environmental impact assessment of the coal combustion and its substitution by alternative fuels from combustible wastes during Portland cement clinker sinterization in rotary cement kiln. Environmental impact assessment was carried out based on the fuels chemical composition and operating parameters of a rotary cement kiln in accordance with EURITS and IMPACT 2002+ methods.

  10. Destruction of DDT wastes in two preheater/precalciner cement kilns in China.

    Science.gov (United States)

    Yan, Dahai; Peng, Zheng; Karstensen, Kåre Helge; Ding, Qiong; Wang, Kaixiang; Wang, Zuguang

    2014-04-01

    The destruction of DDT formulations and DDT contaminated soil was conducted by feeding wastes into the flue gas chamber at the kiln inlet of two different preheater/precalciner cement kilns in China. The concentration of DDT, PCDD/PCDFs and HCB were measured in the flue gas of the main stack, in the solid material under baseline conditions and when feeding DDT-wastes. The destruction efficiency and the destruction and removal efficiency for DDT were in the range of 99.9335%-99.9998% and 99.9984%-99.9999%, respectively. The emissions of PCDD/PCDFs and HCB in the flue gas varied in the range of 0.0019-0.0171 ng I-TEQ/Nm(3) and 0.0064-0.0404 μg/Nm(3), respectively. The emission factor for PCDD/PCDF and HCB varied from 0.0137 to 0.0281 μg/ton and from 17.32 to 109.34 μg/ton of clinker, respectively. The concentration of PCDD/PCDFs and HCB in solid samples decreased as follows: cement kiln dust, 4.1-5 ng I-TEQ/kg and 0.70-0.71 μg/kg, respectively; >raw meal, 0.82-0.97 ng I-TEQ/kg and 0.18 μg/kg, respectively; >cement clinker, 0.09-0.22 ng I-TEQ/kg and 0.14-0.18 μg/kg, respectively. This study indicates that the feeding of DDT and POPs-wastes to the lower temperature part of a cement kiln system possibly to create a buildup of trace not-destroyed compounds in the system and might cause emissions; the technical feasibility and the environmental acceptability of this practice need to be investigated thoroughly.

  11. Combustion of solid alternative fuels in the cement kiln burner

    DEFF Research Database (Denmark)

    Nørskov, Linda Kaare

    In the cement industry there is an increasing environmental and financial motivation for substituting conventional fossil fuels with alternative fuels, being biomass or waste derived fuels. However, the introduction of alternative fuels may influence emissions, cement product quality, process...... stability, and process efficiency. Alternative fuel substitution in the calciner unit has reached close to 100% at many cement plants and to further increase the use of alternative fuels rotary kiln substitution must be enhanced. At present, limited systematic knowledge of the alternative fuel combustion...... modelling, data collection and observations at an industrial cement plant firing alternative fuels. Alternative fuels may differ from conventional fossil fuels in combustion behaviour through differences in physical and chemical properties and reaction kinetics. Often solid alternative fuels are available...

  12. Combustion of large solid fuels in cement rotary kilns

    DEFF Research Database (Denmark)

    Nielsen, Anders Rooma

    (MBM), waste wood, sewage sludge, paper and plastics. The alternative fuel share of the total energy varies significantly from region to region, but the general trend is towards increased alternative fuel utilization. Solid alternative fuels typically have physical and chemical properties that differ......The cement industry has a significant interest in replacing fossil fuels with alternative fuels in order to minimize production costs and reduce CO2 emissions. These new alternative fuels are in particular solid fuels such as refuse derived fuel (RDF), tire-derived fuel (TDF), meat and bone meal...... from traditional solid fossil fuels. This creates a need for new combustion equipment or modification of existing kiln systems, because alternative fuels may influence process stability and product quality. Process stability is mainly influenced by exposing the raw material bed in the rotary kiln...

  13. 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.

  14. Combustion of large solid fuels in cement rotary kilns

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Anders Rooma

    2012-03-15

    The cement industry has a significant interest in replacing fossil fuels with alternative fuels in order to minimize production costs and reduce CO{sub 2} emissions. These new alternative fuels are in particular solid fuels such as refuse derived fuel (RDF), tire-derived fuel (TDF), meat and bone meal (MBM), waste wood, sewage sludge, paper and plastics. This thesis provides an insight into the utilization of solid alternative fuels in the material inlet end of rotary kilns. This position is interesting because it allows utilization of large fuel particles, thereby eliminating the need for an expensive shredding of the fuels. The challenge, however, is that the solid fuels will be mixed into the cement raw materials, which is likely to affect process stability and clinker quality, as described above. The mixing of fuels and raw materials was studied experimentally in a pilot-scale rotary drum and was found to be a fast process, reaching steady state within few drum revolutions. Thus, heat transfer by conduction from the cement raw materials to the fuel particles is a major heat transfer mechanism rather than convection or radiation from the freeboard gas above the material bed. Consequently, the temperature of the cement raw materials becomes a factor of great importance for heating the fuel particles. Combustion of different alternative fuels has been investigated experimentally in a pilot-scale rotary furnace under conditions similar to those in the material inlet end of cement rotary kilns. The main focus was on tire rubber and pine wood which are relevant fuels in this context. Heating, drying and devolatilization of alternative fuels are fast processes that primarily depend on heat transfer and fuel particle size. Devolatilization of a large wood or tire particle with a thickness of 20 mm at 900 deg. C is for example around 2 minutes. By contrast, char oxidation is a slow process which may greatly reduce the amounts of solid fuels to be utilized in the

  15. Modeling and optimization of rotary kiln treating EAF dust

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Electric arc furnace (EAF) dust from steel industries is listed by the United Sates EPA as a hazardous waste under the regulations of the Resource Conservation and Recovery Act due to the presence of lead, cadmium and chlorine. The disposal of the approximately 650000 t of EAF dust per year in the U.S. and Canada is an expensive and unresolved problem for the majority of steel companies. The Waelz process has been considered as the best process for treating the EAF dust. A process model, combined thermodynamic modeling with heat transfer calculations, has been developed to simulate the chemical reactions, mass and heat transfer and heat balance in the kiln. The injection of air into the slag and the temperature profile along the kiln have been modeled. The effect of (CaO+MgO)/SiO2 on the solidus temperature of slag has also been predicted and discussed. Some optimized results have been presented.

  16. Carpet As An Alternative Fuel in Cement Kilns

    Energy Technology Data Exchange (ETDEWEB)

    Matthew J Realff

    2007-02-06

    Approximately 5 billion lbs of carpet will be removed from buildings in the US each year for the foreseeable future. This carpet is potentially a valuable resource because it contains plastic in the face of the carpet that can be re-used. However, there are many different types of carpet, and at least four major different plastics used to make the face. The face is woven through a backing fabric and held in place by a “glue” that is in most cases a latex cross-linked polymer which is heavily loaded with chalk (calcium carbonate). This backing has almost no value as a recycled material. In addition, carpet is a bulky material that is difficult to handle and ship and must be kept dry. It would be of significant benefit to the public if this stream of material could be kept out of landfills and some of its potential value unlocked by having high volume alternatives for recycled carpet use. The research question that this project investigated was whether carpet could be used as a fuel in a cement kiln. If this could be done successfully, there is significant capacity in the US cement industry to absorb carpet and use it as a fuel. Cement kilns could serve as a way to stimulate carpet collection and then side streams be taken for higher value uses. The research demonstrated that carpet was technically a suitable fuel, but was unable to conclude that the overall system could be economically feasible at this time with the constraints placed on the project by using an existing system for feeding the kiln. Collection and transportation were relatively straightforward, using an existing collector who had the capacity to collect high volumes of material. The shredding of the carpet into a suitable form for feeding was more challenging, but these problems were successfully overcome. The feeding of the carpet into the kiln was not successfully carried out reliably. The overall economics were not positive under the prevailing conditions of costs for transportation and size

  17. Increasing Plant Availability by Mechanical Checking of the Cement Rotary Kiln Axis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A periodic check of the cement rotary kiln axis is needed within the framework of preventive maintenance for maintaining high plant availability. The fourth generation “KAS-4” measuring system was developed by Wuhan University of Technology in 1999. The system can be carried out with rotating or stationary kiln plant. The same is true of the measurement of tire and supporting roller diameters, the clearance of tires, the position of rollers, the machining of tires and rollers, the slopes of roller surfaces, the deflection of gear, the axis of kiln. The system has been applied to the measurement for 10 sets of cement rotary kiln in China.

  18. [Patterns of PCDD/Fs, PCBs and PCNs homologues in fly ash from cement kilns].

    Science.gov (United States)

    Zhang, Jing; Ni, Yu-Wen; Zhang, Hai-Jun; Zhang, Xue-Ping; Zhang, Qing; Chen, Ji-Ping

    2009-02-15

    The concentrations and toxic equivalent (TEQ) values of PCDD/Fs, PCBs and PCNs in fly ash collected from three types of cement kilns (vertical shaft kiln, wet-process rotary kiln and dry-process rotary kiln) and two types of waste incinerators were determined, and the patterns of homologues and congeners were compared. The results showed that the total TEQ of PCDD/Fs, PCBs and PCNs in cement kiln fly ash, which were in the range of 4.0-62, 0.069-3.9 and 0.47-2.8 ng x kg(-1) respectively, were much lower than that of fly ash from waste incinerators. In cement kiln fly ash, the predominating PCDD/Fs homologues were TCDFs, and the chief 2, 3, 7, 8-PCDD/Fs congeners were OCDD, 2, 3, 7, 8-TCDF and 1, 2, 3, 4, 6, 7, 8-HpCDF. The patterns of PCBs homologues in cement kiln fly ash were similar to those of waste incinerators in which TeCB were predominating homologues. PCB77, PCB105, PCB118 were at higher concentrations than other co-polar PCBs. Different types of cement kiln fly ash presented similar PCNs homologue patterns. The predominant homologues were TeCN, whereas OcCN were not detected. PCN 66/67 which has dioxin like toxity was the most abundant congener in all fly ash.

  19. Impact of kiln thermal energy demand and false air on cement kiln flue gas CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Arachchige, Udara S.P.R.; Kawan, Dinesh; Tokheim, Lars-Andre [Telemark University College, Porsgrunn (Norway); Melaaen, Morten C. [Telemark University College, Porsgrunn (Norway); (Tel-Tek, Porsgrunn (Norway)

    2013-07-01

    The present study is focused on the effect of the specific thermal energy demand and the false air factor on carbon capture applied to cement kiln exhaust gases. The carbon capture process model was developed and implemented in Aspen Plus. The model was developed for flue gases from a typical cement clinker manufacturing plant. The specific thermal energy demand as well as the false air factor of the kiln system were varied in order to determine the effect on CO2 capture plant performance, such as the solvent regeneration energy demand. In general, an increase in the mentioned kiln system factors increases the regeneration energy demand. The reboiler energy demand is calculated as 3270, 3428 and 3589 kJ/kg clinker for a specific thermal energy of 3000, 3400 and 3800 kJ/kg clinker, respectively. Setting the false air factor to 25, 50 or 70% gives a reboiler energy demand of 3428, 3476, 3568 kJ/kg clinker, respectively.

  20. [Comparison of fixation effects of heavy metals between cement rotary kiln co-processing and cement solidification/stabilization].

    Science.gov (United States)

    Zhang, Jun-li; Liu, Jian-guo; Li, Cheng; Jin, Yi-ying; Nie, Yong-feng

    2008-04-01

    Both cement rotary kiln co-processing hazardous wastes and cement solidification/stabilization could dispose heavy metals by fixation. Different fixation mechanisms lead to different fixation effects. The same amount of heavy metal compounds containing As, Cd, Cr, Cu, Pb, Zn were treated by the two kinds of fixation technologies. GB leaching test, TCLP tests and sequential extraction procedures were employed to compare the fixation effects of two fixation technologies. The leached concentration and chemical species distribution of heavy metals in two grounded mortar samples were analyzed and the fixation effects of two kinds of technologies to different heavy metals were compared. The results show the fixation effect of cement rotary kiln co-processing technology is better than cement solidification/stabilization technology to As, Pb, Zn. Calcinations in cement rotary kiln and then hydration help As, Pb, Zn contained in hazardous wastes transform to more steady chemical species and effectively dispose these heavy metals compounds. Cr3+ is liable to be converted to much more toxic and more mobile Cr6+ state in cement rotary kiln. And so Cr wastes are more fit for treatment by cement solidification/stabilization technology. The work could provide a basis when choosing disposal technologies for different heavy metals and be helpful to improve the application and development of cement rotary kiln co-processing hazardous wastes.

  1. 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 ...

  2. Optimum feeding rate of solid hazardous waste in a cement kiln burner

    OpenAIRE

    2013-01-01

    Solid hazardous waste mixed with wood chips (SHW) is a partly CO2 neutral fuel, and hence is a good candidate for substituting fossil fuels like pulverized coal in rotary kiln burners used in cement kiln systems. SHW is used in several cement plants, but the optimum substitution rate has apparently not yet been fully investigated. The present study aims to find the maximum possible replacement of coal by SHW, without negatively affecting the product quality, emissions and overall operation of...

  3. Temperature prediction and analysis based on BP and Elman neural network for cement rotary kiln

    Science.gov (United States)

    Yang, Baosheng; Ma, Xiushui

    2011-05-01

    In order to reduce energy consumption and improve the stability of cement burning system production, it is necessary to conduct in-depth analysis of the cement burning system, control the operation state and law of the system. In view of the rotary kiln consumes most of the fuel, we establish the simulation model of the cement kiln used to find effective control methods. It is difficult to construct mathematical model for the rotary cement kiln as the complex parameters, so we expressed directly using neural network method to establish the simulation model for the kiln. Choosing reasonable state and control variables and collecting actual operation data to train neural network weights. We first in-depth analyze mechanism and working parameters correlation to determine factors of the yield and quality as the model input variables; then constructed cement kiln model based on BP and Elman network, both achieved good fitting results. Elman network model has a faster convergence speed, high precision and good generalization ability. So the Elman network based model can be used as simulation model of the cement rotary kiln for exploring new control method.

  4. Energy recovery from wastes : experience with solid alternative fuels combustion in a precalciner cement kiln

    OpenAIRE

    Tokheim, Lars-André; Gautestad, Tor; Axelsen, Ernst Petter; Bjerketvedt, Dag

    2001-01-01

    Today virtually all cement clinker burning processes take place in rotary kilns. A mixture of calcareous and argilaceous materials is heated to a temperature of about 1450 °C. In this process decarbonation followed by partial fusion occurs, and nodules of so-called clinker are formed. The cooled clinker is mixed with a few percent of gypsum, and ground into a fine meal – cement. The most modern cement kilns are equipped with a precalciner, in which most of the calcium carbonate...

  5. 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

    2017-02-28

    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.

  6. Application of the Hand-instrument of Measurement of Tyre Gap and Diameter in Cement Rotary Kiln

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This article is concerned with the cement rotary kiln, the hand-instrument of measurements of tyre gap and the outer diameter. The accuracy of measurements of tyre gap and diameter is less than ±1mm. The hand- instrument wins two patents in China. It has been applied to the measurement for 16 sets of cement rotary kiln in China.

  7. Impact of kiln thermal energy demand and false air on cement kiln flue gas CO2 capture

    Directory of Open Access Journals (Sweden)

    Udara S. P. R. Arachchige, Dinesh Kawan, Lars-André Tokheim, Morten C. Melaaen

    2014-01-01

    Full Text Available The present study is focused on the effect of the specific thermal energy demand and the false air factor on carbon capture applied to cement kiln exhaust gases. The carbon capture process model was developed and implemented in Aspen Plus. The model was developed for flue gases from a typical cement clinker manufacturing plant. The specific thermal energy demand as well as the false air factor of the kiln system were varied in order to determine the effect on CO2 capture plant performance, such as the solvent regeneration energy demand. In general, an increase in the mentioned kiln system factors increases the regeneration energy demand. The reboiler energy demand is calculated as 3270, 3428 and 3589 kJ/kg clinker for a specific thermal energy of 3000, 3400 and 3800 kJ/kg clinker, respectively. Setting the false air factor to 25, 50 or 70% gives a reboiler energy demand of 3428, 3476, 3568 kJ/kg clinker, respectively.

  8. SO2 Release as a Consequence of Alternative Fuel Combustion in Cement Rotary Kiln Inlets

    OpenAIRE

    Cortada Mut, Maria del Mar; Nørskov, Linda Kaare; Glarborg, Peter; Dam-Johansen, Kim

    2015-01-01

    The combustion of alternative fuels in direct contact with the bed material of the rotary kiln may cause local reducing conditions and, subsequently, decomposition of sulfates from cement raw materials, increasing the SO2 concentration in the gas phase. The decomposition of sulfates increases the sulfur circulation and may be problematic because high sulfur circulation can cause sticky material buildup, affecting the process operation of the cement kiln system. The SO2 release from cement raw...

  9. Dynamic measurement of mercury adsorption and oxidation on activated carbon in simulated cement kiln flue gas

    DEFF Research Database (Denmark)

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

    2012-01-01

    elemental mercury shows that when HCl is present with either SO2 or NOx the mercury measurement after the converter is unstable and lower than the elemental mercury inlet level. The conclusion is that red brass chips cannot fully reduce oxidized mercury to elemental mercury when simulated cement kiln gas...

  10. Test burn with PCB-oil in a local cement kiln in Sri Lanka.

    Science.gov (United States)

    Karstensen, Kåre Helge; Mubarak, Azeez M; Gunadasa, H N; Wijagunasekara, Bandulasoma; Ratnayake, Niranjanie; Alwis, Ajith De; Fernando, Jayavilal

    2010-02-01

    The production and use of polychlorinated biphenyls (PCBs) have ceased and most developed countries have disposed off their stocks long time ago. PCBs can however still be found in the environment and one important source is accumulated stocks in developing countries. Sound treatment of PCB is costly and most developing countries do not have dedicated hazardous waste incinerators or non-combustion technologies available for domestic disposal and can usually not afford export. High temperature cement kilns have been used to treat organic hazardous wastes in developed countries for decades and shown to constitute a sound option if well managed and controlled. In contrast to dedicated hazardous waste incinerators and other treatment techniques, cement kilns are already in place in virtually every country and may constitute a treatment option. The objective of this study was therefore to carry out the first test burn with PCB-oil in a developing country cement kiln and to assess its feasibility and destruction performance. The 3 d test burn demonstrated that the Sri Lankan cement kiln was able to destroy PCB in an irreversible and environmental sound manner without causing any new formation of PCDD/PCDF or HCB. The destruction and removal efficiency (DRE) was better than 99.9999% at the highest PCB feeding rate.

  11. ZrO2—Containing Refractories for Cement Rotary Kilns

    Institute of Scientific and Technical Information of China (English)

    YEGuotian; XUYanqing

    2002-01-01

    ZrO2-Containing Refractories have been increasingly used for cement rotary kilns,This paper discusses how the properties and performance of ZrO2-Containing Refractories are improved in terms of chemical attack resistance,thermal shock resistance,thermal conductivity and mechanical stress.

  12. Distribution of Hg, As and Se in material and flue gas streams from preheater-precalciner cement kilns and vertical shaft cement kilns in China.

    Science.gov (United States)

    Yan, Dahai; Peng, Zheng; Ding, Qiong; Karstensen, Kåre Helge; Engelsen, Christian J; Li, Li; Ren, Yong; Jiang, Chen

    2015-08-01

    The aim of this study was to evaluate the behavior of Hg, As, and Se in cement production. Two types of cement plants were studied, including the vertical shaft kiln (VSK) and preheater-precalciner kiln (PPK) processes. Determination of Hg, As, and Se in the main material and gas streams were performed. It was found that recycling of particulate matter captured by an air pollution control device caused a significant enrichment of Hg and As inside both processes. The total quantity of Hg entering the process and the quantity emitted to the atmosphere were found to be 10-109 and 6.3-38 mg, respectively, per ton of clinker produced. The average Hg emission was calculated to be around 41% of the total mercury input. The emissions found complied with the European Union (EU) limit and exceeded partly the U.S. limit. Furthermore, it was found that oxidized mercury was the dominant species in the PPK process, whereas the reduced form was dominant in the VSK process, due to the oxidizing and reducing gas conditions, respectively. Regarding the distribution of As and Se, the major amounts were bound to the solid materials, that is, cement clinker and particulate matter. Based on cement production data in China in 2013, the annual emissions of Hg and As were estimated to be in the range of 8.6-52 and 4.1-9.5 tons, respectively.

  13. Kiln process impact of alternative solid fuel combustion in the cement kiln main burner - Mathematical modelling and full-scale experiment

    OpenAIRE

    Ariyaratne, Hiromi Wijesinghe; Melaaen, Morten Christian; Tokheim, Lars André; Manjula, Edirisinghe V. P. J.

    2014-01-01

    Increased use of alternative fuels in cement kilns is a trend in the world. However, replacing fossil fuels like coal with different alternative fuels will give various impacts on the overall kiln process due to the fuel characteristics. Hence, it is important to know to what extent the fossil fuels can be replaced by different alternative fuels without severely changing process conditions, product quality or emissions. In the present study, a mass and energy balance for the combustion of dif...

  14. 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.

  15. SO2 Release as a Consequence of Alternative Fuel Combustion in Cement Rotary Kiln Inlets

    DEFF Research Database (Denmark)

    Cortada Mut, Maria del Mar; Nørskov, Linda Kaare; Glarborg, Peter;

    2015-01-01

    The combustion of alternative fuels in direct contact with the bed material of the rotary kiln may cause local reducing conditions and, subsequently, decomposition of sulfates from cement raw materials, increasing the SO2 concentration in the gas phase. The decomposition of sulfates increases...... the sulfur circulation and may be problematic because high sulfur circulation can cause sticky material buildup, affecting the process operation of the cement kiln system. The SO2 release from cement raw materials during combustion of pine wood and tire rubber has been studied experimentally in a high......-temperature rotary drum, focusing on the influence of the fuel particle size and volatile content. The SO2 release increased with a decreasing fuel particle size and with an increasing fuel volatile content. Furthermore, CO, H2, and CH4, which are the main reducing gases released during fuel devolatilization, were...

  16. Effects of bypass system on PCDD/F emission and chlorine circulation in cement kilns.

    Science.gov (United States)

    Zhan, Ming-Xiu; Fu, Jianying; Chen, Tong; Li, Yeqing; Zhang, Jiang; Li, Xiao-Dong; Yan, Jian-Hua; Buekens, Alfons

    2016-10-01

    A bypass at the kiln inlet allows the effective reduction of alkali chloride cycles and thus perhaps affects the emission of PCDD/Fs. Effects of bypass system on PCDD/F emission and chlorine circulation were studied in two typical dry cement kilns with 5000 ton/day clinker capacity in China and named CK1 and CK2, respectively. Firstly, the emission level of PCDD/Fs with the operation of bypass system was estimated in CK1, to certify that bypass system has a perfect adaption to the cement kiln regarding the PCDD/F emission even with the refuse derived fuel (RDF) as the replacement of fuel. On the other hand, the operating conditions in the CK2 were scrutinised by monitoring the concentrations of SO2, NH3 and HCl. In addition, the characteristics of raw meal, clinker, bag filter ash and bypass ash were also investigated by Energy Dispersive Spectrometer (EDS), metal and chlorine analysis. The balance of chlorine showed that 18 % of the possible accumulated chlorine could be ejected from the cement kiln system when 2 % of kiln exhaust gas was extracted. Furthermore, the emission level of PCDD/Fs in the main flue gas also decreased from 0.037 ± 0.035 ng I-TEQ/Nm(3) to 0.019 ± 0.007 ng I-TEQ/Nm(3) with a reduction efficiency of 48.2 %. Most importantly, PCDD/F emission from the bypass system was proven to have rather minor effect on the total emission factor. The congener distributions of PCDD/Fs were also analysed in the flue gas and fly ash, before and after application of bypass system, to find cues to the formation mechanism.

  17. Plant Test of Industrial Waste Disposal in a Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    刘阳生; 韩杰; 等

    2003-01-01

    Destruction of industrial waste in cement rotary kilins(CRKs) is an alternative technology for the treatment of certain types of industrial waste(IW).In this paper,three typical types of industrial wastes were co-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal(especially solid waste disposal )on the quality of clinker and the concentration of pollutants in air emission.Experimental results show that(1) waste disposal does not affect the quality of clinker and fly ash,and fly ash after the IW disposal can still be used in the cement production,(2) heavy metals from IW are immobilized and stabilized in the clinker and cement,and (3) concentration of pollutants in air emission is far below than the permitted values in the China National Standard-Air Pollutants Emission Standard(GB 16297-1996).

  18. Optimum feeding rate of solid hazardous waste in a cement kiln burner

    Directory of Open Access Journals (Sweden)

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

    2013-01-01

    Full Text Available Solid hazardous waste mixed with wood chips (SHW is a partly CO2 neutral fuel, and hence is a good candidate for substituting fossil fuels like pulverized coal in rotary kiln burners used in cement kiln systems. SHW is used in several cement plants, but the optimum substitution rate has apparently not yet been fully investigated. The present study aims to find the maximum possible replacement of coal by SHW, without negatively affecting the product quality, emissions and overall operation of the process. A full-scale experiment was carried out in the rotary kiln burner of a cement plant by varying the SHW substitution rate from 0 to 3 t/hr. Clinker quality, emissions and other relevant operational data from the experiment were analysed using fuel characteristics of coal and SHW. The results revealed that SHW could safely replace around 20% of the primary coal energy without giving negative effects. The limiting factor is the free lime content of the clinker. Results from the present study were also compared with results from a previous test using meat and bone meal.

  19. Optimum feeding rate of solid hazardous waste in a cement kiln burner

    Energy Technology Data Exchange (ETDEWEB)

    Ariyaratne, W.K. Hiromi; Melaaen, Morten C.; Tokheim, Lars-Andre [Telemark University College, Faculty of Technology, Kjoelnes Ring 56, P.O. Box 203, N-3901, Porsgrunn (Norway)

    2013-07-01

    Solid hazardous waste mixed with wood chips (SHW) is a partly CO2 neutral fuel, and hence is a good candidate for substituting fossil fuels like pulverized coal in rotary kiln burners used in cement kiln systems. SHW is used in several cement plants, but the optimum substitution rate has apparently not yet been fully investigated. The present study aims to find the maximum possible replacement of coal by SHW, without negatively affecting the product quality, emissions and overall operation of the process. A full-scale experiment was carried out in the rotary kiln burner of a cement plant by varying the SHW substitution rate from 0 to 3 t/hr. Clinker quality, emissions and other relevant operational data from the experiment were analysed using fuel characteristics of coal and SHW. The results revealed that SHW could safely replace around 20% of the primary coal energy without giving negative effects. The limiting factor is the free lime content of the clinker. Results from the present study were also compared with results from a previous test using meat and bone meal.

  20. Utilization of waste heat from rotary kiln for burning clinker in the cement plant

    Directory of Open Access Journals (Sweden)

    Sztekler Karol

    2016-01-01

    Full Text Available Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO2 emissions reduction in addition to the recovery of waste heat is also alternative fuels co-firing in cement kilns [1], [2]. In the cement sector interest in fitting-usable waste energy is growing in order to achieve high rates of savings and hence the financial benefits, as well as the environment ones [3]. In the process of cement production is lost irretrievably lot of energy and reduction of these losses on a global scale gives a visible saving of consumed fuel. The aim of this study is to investigate the possibility of waste heat use in Rudniki Cement Plant near to Czestochowa. After analyzing of all waste heat sources will be analyzed the heat emitted by radiation from the surface of the rotary kiln at the relevant facility. On the basis of thermal-flow calculations the most favorable radiative heat exchanger will be designed. The calculations based on available measurements provided by the cement plant, a thermal power of the heat exchanger, the heat exchange surface, the geometry of the heat exchanger, and other important parameters will be established. In addition the preliminary calculations of hydraulic losses and set directions for further work will be carried out. Direct benefits observed with the introduction of the broader heat recovery technology, is a significant increase in energy efficiency of the industrial process, which is reflected in the reduction of energy consumption and costs. Indirectly it leads to a reduction of pollution and energy consumption.

  1. Modification of the inlet to the tertiary air duct in the cement kiln installation

    Directory of Open Access Journals (Sweden)

    Borsuk Grzegorz

    2016-12-01

    Full Text Available Rotary kiln installation forms a very complex system, as it consists of various components which affect cement production. However, some problems with particle settling are encountered during operation of tertiary air installation. This paper reports on the results of a study into gas-particle flow in a tertiary air duct installation. This flow was calculated using Euler method for air motion and Lagrange method for particle motion. The results in this paper demonstrate that study focus on the tertiary air installation is a practical measure without the analysis of other processes in the rotary kiln. A solution to this problem offers several alternatives of modifying the inlet to the tertiary air duct. As a result of numerical calculations, we demonstrate the influence of geometry of a rotary kiln modification on the number of large particles transported in the tertiary air duct. The results indicate that in order to reduce large particles, rotary kiln head geometry needs to be modified, and a particle settler should be installed at its outlet.

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

    Science.gov (United States)

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

    2014-08-15

    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.

  3. Distributions, profiles and formation mechanisms of polychlorinated naphthalenes in cement kilns co-processing municipal waste incinerator fly ash.

    Science.gov (United States)

    Liu, Guorui; Zhan, Jiayu; Zhao, Yuyang; Li, Li; Jiang, Xiaoxu; Fu, Jianjie; Li, Chunping; Zheng, Minghui

    2016-07-01

    Co-processing municipal solid waste incinerator (MSWI) fly ash in cement kilns is challenging because the unintentional production of persistent organic pollutants (POPs) during the process is not well understood. The distributions, profiles and formation mechanisms of polychlorinated naphthalenes (PCNs) as new POPs covered under Stockholm Convention in two cement kilns co-processing MSWI fly ash were studied. The average concentrations of PCNs in stack gas samples were 710 ng m(-3). The PCN concentration in particle samples collected from different process stages in the cement kilns ranged from 1.1 to 84.7 ng g(-1). Three process sites including suspension pre-heater boiler, humidifier tower, and the kiln back-end bag filter were identified to be the major formation sites of PCNs in cement kilns co-processing MSWI fly ash. The PCN distribution patterns were similar to that of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs), which indicates the possibility for simultaneous control of PCNs and PCDD/Fs in cement kilns co-processing fly ash. Chlorination was suggested to be an important formation mechanism of PCNs, and chlorination pathways of PCN congeners are proposed based on the congener profiles. Thermodynamic calculations, including relative thermal energies (ΔE) and standard free energy of formation (ΔG), and the charge densities of the carbon atoms in PCN supported the proposed chlorination mechanisms for PCN formation. The results presented in this study might provide helpful information for developing techniques and strategies to control PCN emissions during cement kilns co-processing MSWI fly ash.

  4. Sulfur Release during Alternative fuels Combustion in Cement Rotary Kilns

    DEFF Research Database (Denmark)

    Cortada Mut, Maria del Mar

    Cement production is an energy-intensive process, whic h has traditionally been dependent on fossil fuels. However, the usage of selected waste, biomass, and by-products with recoverable calorific value, defined as alternative fuels, is increasing and their combustion is mo re challenging compared...... in order to separate the influence of the simultaneous phenomena occurring in the experimental set-up, such as mixing th e fuel with the bed material, heating up of a particle, 5 iii Abstract Cement production is an energy-intensive process, whic h has traditionally been dependent on fossil fuels. However...... to fossil fuels, due to the lack of experience in handling the different and va rying combustion characteristics caused by different chemical and physical properties, e.g. higher moisture content and larger particle sizes. When full combustion of alternative fuels in the calcin er and/or main burner...

  5. Sulfur Release during Alternative fuels Combustion in Cement Rotary Kilns

    OpenAIRE

    Cortada Mut, Maria del Mar; Dam-Johansen, Kim; Glarborg, Peter; Nørskov, Linda Kaare

    2014-01-01

    Cement production is an energy-intensive process, whic h has traditionally been dependent on fossil fuels. However, the usage of selected waste, biomass, and by-products with recoverable calorific value, defined as alternative fuels, is increasing and their combustion is mo re challenging compared to fossil fuels, due to the lack of experience in handling the different and va rying combustion characteristics caused by different chemical and physical properties, e.g. higher moisture content an...

  6. Increasing Energy Efficiency and Reducing Emissions from China's Cement Kilns. Audit Report of Two Cement Plants in Shandong Province, China

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thekdi, Arvind [E3M, Inc., St. Paul, MN (United States); Lan, Wang [China Building Materials Academy, Beijing (China)

    2011-07-01

    The study documented in this report was initiated in order to conduct an energy assessment and to identify the relationship between combustion issues and emissions from cement kilns. A new suspension preheater/precalciner (NSP) rotary cement kiln at one cement manufacturing facility (referred to as Shui Ni 1 in this report) and a vertical shaft kiln (VSK) at another cement manufacturing facility (referred to as Shui Ni 2 in this report), which are both in Shandong Province, were selected to conduct the energy and emission assessments through collection of data. Based on analysis of the data collected during this assessment, several actions are suggested that could lead to reduction in coal use and reduction in emission of gaseous pollutants from the system.

  7. The effect of alternative fuel combustion in the cement kiln main burner on production capacity and improvement with oxygen enrichment.

    OpenAIRE

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

    2013-01-01

    A mathematical model based on a mass and energy balance for the combustion in a cement rotary kiln was developed. The model was used to investigate the impact of replacing about 45 % of the primary coal energy by different alternative fuels. Refuse derived fuel, waste wood, solid hazardous waste and liquid hazardous waste were used in the modeling. The results showed that in order to keep the kiln temperature unchanged, and thereby maintain the required clinker quality, the production capa...

  8. Degradation of Alumina and Magnesia Chrome refractory bricks in Portland cement kiln – Corrected version*

    Directory of Open Access Journals (Sweden)

    Ben Addi K.

    2014-05-01

    Full Text Available In cement plants, the refractory products are particularly confronted to partially liquid oxide phases at temperature ranging between 900°C and 1700°C. All constituents of these products have to resist not only to thermal constraints, but also to the thermochemical solicitations which result from contact material/coating. In order to study the phenomenon of degradation of refractory bricks in cement kilns and to identify the causes of their degradation, we proceed to the examination of industrial cases in cement kiln. Many chemical tests of the degraded refractory bricks have been done and the results acquired were compared to the ones not used. The analysis of the results is doing using different techniques (Loss of ignition, X-ray Fluorescence, X-ray Diffraction. The results show that the degradation of the used bricks in the clinkering and cooling zone is due to the infiltration of aggressive elements such us sulphur, alkali (Na2O, K2O .... The chemical interaction between the Portland clinker phases and refractory material has also an importance on the stability of the coating and consequently on the life of the refractories.

  9. Cancer risk evaluation of brick kiln workers exposed to dust bound PAHs in Punjab province (Pakistan).

    Science.gov (United States)

    Kamal, Atif; Malik, Riffat Naseem; Martellini, Tania; Cincinelli, Alessandra

    2014-09-15

    Principal objective of this study was to evaluate the health risks of brick kiln workers to dust bound PAHs exposure in Punjab province (Pakistan). To this aim, surface dust samples were collected from brick kiln units located in Chung Khurd (Lahore city), Gujranwala city and Sohra village (in the vicinity of Gujranwala). The highest ΣPAH levels were measured in the dust samples collected in Sohdra village (mean 2578 ng g(-1) d.w., range 302-6757 ng g(-1) d.w.) followed by Gujranwala city (mean 957, range 16.1-1963 ng g(-1) d.w.) and Chung Khurd (mean 882, range 692-1007 ng g(-1) d.w.). Source identification using diagnostic ratios and principal component analysis identified coal and wood combustion as the major PAHs sources. The cancer risk model (CR-Model 1) and the Incremental Lifetime Cancer Risk model (ILCR-Model 2) were used to evaluate the cancer risk assessment via ingestion, inhalation and dermal contact pathways. Both models suggested that brick kiln workers (including adults and children) were exposed to high-potential carcinogenic risk via both ingestion and dermal contact pathways during the brick making process. This study also emphasizes the need for pollution control in the brick kiln industry of Pakistan.

  10. SO2 Release as a Consequence of Alternative Fuel Combustion in Cement Rotary Kiln Inlets

    DEFF Research Database (Denmark)

    Cortada Mut, Maria del Mar; Nørskov, Linda Kaare; Glarborg, Peter;

    2015-01-01

    The combustion of alternative fuels in direct contact with the bed material of the rotary kiln may cause local reducing conditions and, subsequently, decomposition of sulfates from cement raw materials, increasing the SO2 concentration in the gas phase. The decomposition of sulfates increases......-temperature rotary drum, focusing on the influence of the fuel particle size and volatile content. The SO2 release increased with a decreasing fuel particle size and with an increasing fuel volatile content. Furthermore, CO, H2, and CH4, which are the main reducing gases released during fuel devolatilization, were...

  11. Characterization of vapor phase mercury released from concrete processing with baghouse filter dust added cement.

    Science.gov (United States)

    Wang, Jun; Hayes, Josh; Wu, Chang-Yu; Townsend, Timothy; Schert, John; Vinson, Tim; Deliz, Katherine; Bonzongo, Jean-Claude

    2014-02-18

    The fate of mercury (Hg) in cement processing and products has drawn intense attention due to its contribution to the ambient emission inventory. Feeding Hg-loaded coal fly ash to the cement kiln introduces additional Hg into the kiln's baghouse filter dust (BFD), and the practice of replacing 5% of cement with the Hg-loaded BFD by cement plants has recently raised environmental and occupational health concerns. The objective of this study was to determine Hg concentration and speciation in BFD as well as to investigate the release of vapor phase Hg from storing and processing BFD-added cement. The results showed that Hg content in the BFD from different seasons ranged from 0.91-1.44 mg/kg (ppm), with 62-73% as soluble inorganic Hg, while Hg in the other concrete constituents were 1-3 orders of magnitude lower than the BFD. Up to 21% of Hg loss was observed in the time-series study while storing the BFD in the open environment by the end of the seventh day. Real-time monitoring in the bench system indicated that high temperature and moisture can facilitate Hg release at the early stage. Ontario Hydro (OH) traps showed that total Hg emission from BFD is dictated by the air exchange surface area. In the bench simulation of concrete processing, only 0.4-0.5% of Hg escaped from mixing and curing BFD-added cement. A follow-up headspace study did not detect Hg release in the following 7 days. In summary, replacing 5% of cement with the BFD investigated in this study has minimal occupational health concerns for concrete workers, and proper storing and mixing of BFD with cement can minimize Hg emission burden for the cement plant.

  12. Organic and inorganic pollutants from cement kiln stack feeding alternative fuels.

    Science.gov (United States)

    Conesa, Juan A; Gálvez, Araceli; Mateos, Fernán; Martín-Gullón, Ignacio; Font, Rafael

    2008-10-30

    In this work, an analysis of the emission of different pollutants when replacing partially the fuel type used in a cement kiln is done. The wastes used to feed the kiln were tyres and two types of sewage sludge. The increasing mass flow of sludge is between 700 kg h(-1) and 5,500 kg h(-1)1, for a total production of clinker of 150th(-1), whereas the fed tyres were in the flow range of 500-1,500 kg h(-1). Dioxins and furans, polycyclic aromatic hydrocarbons (PAHs) and other hydrocarbons, heavy metals, HCl and HF, CO, CO(2), NO(x) and other parameters of the stack were analyzed, according to the standard methods of sampling and determination, through more than 1 year in six series: one blank (no sewage sludge) and five more with increasing amount of sludge and/or tyres. The emission of PAHs and dioxins seems to increase with the amount of tyres fed to the kiln, probably due to the fed point used for this waste.

  13. Comparison of the fixation effects of heavy metals by cement rotary kiln co-processing and cement based solidification/stabilization.

    Science.gov (United States)

    Zhang, Junli; Liu, Jianguo; Li, Cheng; Jin, Yiying; Nie, Yongfeng; Li, Jinhui

    2009-06-15

    Cement rotary kiln co-processing of hazardous wastes and cement based solidification/stabilization could both immobilize heavy metals. The different retention mechanisms of the two technologies lead to different fixation effects of heavy metals. The same amount of heavy metal compounds were treated by the two types of fixation technologies. Long-term leaching test (160 days), the maximum availability leaching test (NEN 7341) and a modified three-step sequential extraction procedure, proposed by the Commission of the European Communities Bureau of Reference (BCR) were employed to compare the fixation effects of the two fixation technologies. The leaching concentrations in NEN 7341 and long-term leaching tests were compared with identification standard for hazardous wastes (GB5085.3-1996) and drinking water standard (GB5749-2005). The results indicate that the leaching concentrations of the long-term leaching test and NEN 7341 test were lower than the regulatory limits and the leached ratios were small. Both cement based solidification/stabilization and cement rotary kiln co-processing could effectively fix heavy metals. Calcination in a cement rotary kiln and the following hydration that follows during cement application could fix As, Cd, Pb and Zn more effectively and decrease the release to the environment. Cement solidification/stabilization technology has better effect in immobilizing Cr and Ni. Cr wastes are more fitful to be treated by cement solidification/stabilization.

  14. Effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions.

    Science.gov (United States)

    Lv, Dong; Zhu, Tianle; Liu, Runwei; Lv, Qingzhi; Sun, Ye; Wang, Hongmei; Liu, Yu; Zhang, Fan

    2016-09-01

    The effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions were systematically investigated in a cement production line in Beijing. The results show that co-processing the sewage sludge was helpful to reduce NOx emission, which primarily depends on the NH3 amount released from the sewage sludge. Meanwhile, NOx and NH3 concentrations in the flue gas have a negative correlation, and the contribution of feeding the sewage sludge to NOx removal decreased with the increase of injection amount of ammonia water in the SNCR system. Therefore, it is suggested that the injection amount of ammonia water in SNCR system may reduce to cut down the operating costs during co-processing the sewage sludge in cement kiln. In addition, the emission of total PAHs seems to increase with the increased amount of the sewage sludge feeding to the cement kiln. However, the distributions of PAHs were barely changed, and lower molecular weight PAHs were mainly distributed in gaseous phase, accounted for the major portion of PAHs when co-processing sewage sludge in cement kiln.

  15. Action-Dependent Adaptive Critic Design Based Neurocontroller for Cement Precalciner Kiln

    Directory of Open Access Journals (Sweden)

    Baosheng Yang

    2009-10-01

    Full Text Available There are many factors that can affect the calciner process of cement production, such as highly nonlinearity and time-lag, making it very difficult to establish an accurate model of the cement precalciner kiln (PCK system. In order to reduce transport energy consumption and to ensure the quality of cement clinker burning, one needs to explore different control methods from the traditional way. Adaptive Critic Design (ACD integrated neural network, reinforcement learning and dynamic programming techniques, is a new optimal method. As the PCK system parameters change frequently with high real-time property, ADACD (Action-Dependant ACD algorithm is used in PCK system to control the temperature of furnace export and oxygen content of exhaust. ADACD does not depend on the system model, it may use historical data to train a controller offline, and then adapt online. Also the BP network of artificial neural network is used to accomplish the network modeling, and action and critic modules of the algorithm. The results of simulation show that, after the fluctuations in the early control period, the controlled parameters tend to be stabilized guaranteeing the quality of cement clinker calcining.

  16. Personal exposure to inhalable cement dust among construction workers.

    Science.gov (United States)

    Peters, Susan; Thomassen, Yngvar; Fechter-Rink, Edeltraud; Kromhout, Hans

    2009-01-01

    Objective- A case study was carried out to assess cement dust exposure and its determinants among construction workers and for comparison among workers in cement and concrete production.Methods- Full-shift personal exposure measurements were performed and samples were analysed for inhalable dust and its cement content. Exposure variability was modelled with linear mixed models.Results- Inhalable dust concentrations at the construction site ranged from 0.05 to 34 mg/m(3), with a mean of 1.0 mg/m(3). Average concentration for inhalable cement dust was 0.3 mg/m(3) (GM; range 0.02-17 mg/m(3)). Levels in the ready-mix and pre-cast concrete plants were on average 0.5 mg/m(3) (GM) for inhalable dust and 0.2 mg/m(3) (GM) for inhalable cement dust. Highest concentrations were measured in cement production, particularly during cleaning tasks (inhalable dust GM = 55 mg/m(3); inhalable cement dust GM = 33 mg/m(3)) at which point the workers wore personal protective equipment. Elemental measurements showed highest but very variable cement percentages in the cement plant and very low percentages during reinforcement work and pouring. Most likely other sources were contributing to dust concentrations, particularly at the construction site. Within job groups, temporal variability in exposure concentrations generally outweighed differences in average concentrations between workers. 'Using a broom', 'outdoor wind speed' and 'presence of rain' were overall the most influential factors affecting inhalable (cement) dust exposure.Conclusion- Job type appeared to be the main predictor of exposure to inhalable (cement) dust at the construction site. Inhalable dust concentrations in cement production plants, especially during cleaning tasks, are usually considerably higher than at the construction site.

  17. Emission of submicron aerosol particles in cement kilns: Total concentration and size distribution.

    Science.gov (United States)

    Rotatori, Mauro; Mosca, Silvia; Guerriero, Ettore; Febo, Antonio; Giusto, Marco; Montagnoli, Mauro; Bianchini, Massimo; Ferrero, Renato

    2015-01-01

    Cement plants are responsible for particle and gaseous emissions into the atmosphere. With respect to particle emission, the greater part of is in the range from 0.05 to 5.0 µm in diameter. In the last years attention was paid to submicron particles, but there is a lack of available data on the emission from stationary sources. In this paper, concentration and size distribution of particles emitted from four cement kilns, in relationship to operational conditions (especially the use of alternative fuel to coal) of the clinker process are reported. Experimental campaigns were carried out by measuring particles concentration and size distribution at the stack of four cement plants through condensation particle counter (CPC) and scanning mobility particle sizer spectrometer (SMPS). Average total particle number concentrations were between 2000 and 4000 particles/cm³, about 8-10 times lower that those found in the corresponding surrounding areas. As for size distribution, for all the investigated plants it is stable with a unimodal distribution (120-150 nm), independent from the fuel used.

  18. Effects of cement flue dust from a cement factory on stress parameters and diversity of aquatic plants.

    Science.gov (United States)

    Erdal, Serkan; Demirtas, Ayten

    2010-07-01

    Cement kiln dusts, made of a complex mixture of elements, include high levels of heavy metals such as fluoride, magnesium, lead, cadmium, nickel, zinc, copper, beryllium and some toxic compounds. Because of the toxic element compositions and radioactive isotope properties of cement kiln dusts, not only terrestrial but also aquatic ecosystems are subjected to greater stress. In the present paper, we investigated the effects of pollution caused by Askale-Erzurum cement factory (CF) on the stress parameters and diversity of aquatic plants. For this purpose, aquatic plant species were collected from the outer zone of the CF. Only three (Lemna minor, Ceratophyllum submersum and Potamogeton natans) of these species were able to be determined in the CF zone. Antioxidant enzyme activities of the collected aquatic plants were measured and compared to their controls. Superoxide dismutase (SOD) activity of P. natans in the CF zone was significantly high compared to their respective control, while it was low in L. minor and C. submersum compared to their controls. Similarly, peroxidase (POX) activity of P. natans was high, while those of L. minor and C. submersum were low compared to their respective controls. On the other side, while catalase (CAT) activities of L. minor and C. submersum were low, that of P. natans did not show an important change compared to their respective controls. Furthermore, we found that hydrogen peroxide (H(2)O(2)) and malondialdehyde (MDA) levels of all the studied plants were also very high compared to their controls. According to these results, it is clear that pollution caused by the CF reduced diversity and number of aquatic plant species. Besides, the obtained data revealed that P. natans have a more resistant defense system than other species.

  19. Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste.

    Science.gov (United States)

    Jin, Rong; Zhan, Jiayu; Liu, Guorui; Zhao, Yuyang; Zheng, Minghui

    2016-09-05

    Pilot studies of unintentionally produced pollutants should be performed before waste being co-processed in cement kilns. Polychlorinated naphthalene (PCN) formation and emission from cement kilns co-processing sorted municipal solid waste, sewage sludge, and waste acid, however, have not previously been studied. Here, PCNs were analyzed in stack gas samples and solid samples from different stages of three cement production runs. PCN destruction efficiencies were higher when waste was co-processed (93.1% and 88.7% in two tests) than when waste was not co-processed (39.1%), so co-processing waste would not increase PCN outputs. The PCN concentrations were higher in particle samples from the C1 preheater and stages at back end of kiln than in particle samples from other stages, suggesting that cyclone preheater and back end of kiln should be focused for controlling PCN emissions. Besides that, based on the variation of PCN concentrations and corresponding operating conditions in different stages, the temperature, feeding materials, and chlorine content were suggested as the main factors influencing PCN formation. The PCN homologue and congener profiles suggested chlorination and dechlorination were the main PCN formation and decomposition pathways, and congeners CN-23, CN-46, and CN-59 appear to be appropriate indicators of PCNs emitted from coal-burning sources.

  20. Coal acid mine drainage treatment using cement kiln dust

    Directory of Open Access Journals (Sweden)

    Edgar Alberto Martínez

    2014-01-01

    Full Text Available Los sulfuros están presentes en distintas rocas. Durante las actividades mineras y el proceso de remoción de sulfuros se pueden producir Drenajes Ácidos de Minería (DAM, con iones de sulfato (SO4-2. Los DAMs son fuente de polución en las actividades mineras y en Colombia su descarga en los cuerpos de agua debe cumplir las regulaciones nacionales (pH entre 5 y 9. Polvo de horno cementero (CKD, con carbonato de calcio principalmente, de una planta de Cementos Argos S.A. fue usado para neutralizar un DAM generado en la biodesulfurización de carbón. Los DAMs neutralizados tuvieron pHs entre 7,72 y 8,05 y la eliminación de sulfatos entre 67% a 70%. El precipitado se secó y analizó para determinar su composición química y mineralógica. Se encontró humedad entre 69% y 81%; yeso con un 50% de pureza aproximadamente y carbonato de calcio. Esta composición lo hace adecuado para uso en la producción de cemento.

  1. Recycling ash into the first stage of cyclone pre-heater of cement kiln.

    Science.gov (United States)

    Zhan, Ming-Xiu; Fu, Jian-Ying; Havukainen, Jouni; Chen, Tong; Li, Xiao-Dong; Yan, Jian-Hua; Buekens, Alfons

    2016-10-01

    Fly ash collected from the bag filter could be recycled into the first stage of the cyclone pre-heater of the cement kiln, resulting in the possible enrichment of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In this study, soxhlet fly ash (SFA) and raw meal (RM) were selected as the basis for the PCDD/F formation experiments. The levels of 2,3,7,8-PCDD/Fs formed on the SFA and RM were observed to be 2550pg/g (157pg I-TEQ/g) and 1142pg/g (55pg I-TEQ/g), respectively. While less 2,3,7,8-PCDD/Fs was detected when SFA was mixed with RM, suggesting that recycling cement kiln ash would not largely increase the concentration of PCDD/Fs in flue gas. Furthermore, the possible influencing factors on the PCDD/F formation were also investigated. The formation of 2,3,7,8-PCDD/Fs was up to 10,871pg/g (380pg I-TEQ/g) with the adding of CuCl2, which was much higher than the results of CuO and activated carbon. Most importantly, the homologue, congener and gas/particle distribution of PCDD/Fs indicated that de novo synthesis was the dominant PCDD/F formation pathway for SFA. Lastly, principal component analysis (PCA) was also conducted to identify the relationship between the compositions of reactant and the properties of PCDD/Fs produced.

  2. Personal exposure to inhalable cement dust among construction workers.

    NARCIS (Netherlands)

    Peters, S.M.; Thomassen, Y.; Fechter-Rink, E.; Kromhout, H.

    2009-01-01

    Objective- A case study was carried out to assess cement dust exposure and its determinants among construction workers and for comparison among workers in cement and concrete production.Methods- Full-shift personal exposure measurements were performed and samples were analysed for inhalable dust and

  3. Theoretical and experimental studies on combustion of alternative fuels in cement kilns

    Energy Technology Data Exchange (ETDEWEB)

    Axelsen, Ernst Petter

    2002-07-01

    In this thesis, the utilization of alternative fuels for NOx reduction by means of reburning and advanced reburning is considered. Laboratory experiments, full-scale experiments and computational fluid dynamic (CFD) simulations are the basis of the thesis. The goal of the work was to characterize alternative fuels used in cement kilns, with focus on the processes taking place in the precalciner of the cement kiln. To facilitate testing under controlled process conditions, a lab-scale circulating fluidized bed combustion (CFBC) reactor was designed and constructed. A co prehensive study on the fluidization regime in CFBC reactors and precalciners was required to ensure and verify that the operational regime in the CFBC reactor was similar to the regime in a precalciner. Different alternative fuels, such as refuse derived fuel, animal meal and solid hazardous waste, were tested in the CFBC reactor, which proved well suited for characterization of alternative fuels and investigations of NOx reduction, even though the operation of a CFBC reactor is quite complex and gives a certain variation in stability. Experiments with and without circulating mass in the CFBC reactor demonstrated the importance of executing the laboratory combustion experiments in an environment similar to that in the full-scale process, i.e. in the precalciner. Animal meal is believed to follow the reduction route of selective non-catalytic r duction or advanced reburning and to have a special capability of reducing NOx during increased NOx concentrations at the reactor inlet. The increased CO emissions during advanced reburning and reburning with animal meal are most likely to be due to the competition for the OH radical during oxidation of CO and of NH{sub 3}. Furthermore, it was shown, for all fuels, that an increased concentration of NOx at the reactor inlet increases the ratio of NOx at the exit and NOx supplied. Full-scale experiments were executed at Norcem's kiln 6 in Brevik, using

  4. The primary evaluation and characterization of obsolete DDT pesticide from a precalciner of a cement kiln.

    Science.gov (United States)

    Li, Yang; Wang, Qi; Huang, Qifei; He, Jie

    2014-01-01

    1,1,1-Trichloro-2,2-bi(4-chlorophenyl)ethane (DDT) pesticide that has been extensively used in agriculture in China in the last century, and even now, has been banned from all purposes. The disposal of obsolete DDT pesticide has been an urgent task for the Chinese government. In order to evaluate the feasibility of co-processing DDT in the current new style dry-process rotary kiln with a precalciner as the feeding point, the destruction efficiency (DE) of DDTs (including p,p(')-DDT, o,p(')-DDT, p,p(')-DDE and p,p(')-DDD), proportion of DDTs in the combustion residue and exhaust gas, and the release of chlorine were studied under different operating conditions of temperature, oxygen content and gas retention time in the laboratory. The DE of DDTs exceeded 99% when the temperature was over 800 °C with enough oxygen. As the temperature increased from 600 °C to 1200 °C, the proportion of p,p(')-DDD increased and p,p(')-DDT decreased but still the main effective component remained in the combustion residue. In the exhaust gas, the most dominant phenomenon was the rapid increase in p,p(')-DDE concentration as the temperature increased. The release of chlorine reached a peak between 800 °C and 900 °C. It was found that the oxygen content had a positive correlation with the process of dechlorination. The proportion of p,p(')-DDE increased as the oxygen content was increased in the exhaust gas. The gas retention time had almost no influenced on the DE of DDTs, but affected the degradation extent of DDTs in the gas phase. These experiments showed that co-processing of obsolete DDT pesticide in cement kiln precalciners is feasible.

  5. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    OpenAIRE

    2009-01-01

    Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight) of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in t...

  6. Peach leaf responses to soil and cement dust pollution.

    Science.gov (United States)

    Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

    2015-10-01

    Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

  7. 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

    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......Mercury is a pollutant of concern and mercury emissions from cement plants are under environmental regulation. After coal-fired power plants, mercury emissions from cement and mineral production are the second largest anthropogenic sources. Compared to fuels, cement raw materials are the major...... 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...

  8. Effects of occupational dust exposure on the health status of portland cement factory workers

    Directory of Open Access Journals (Sweden)

    R Manjula

    2013-07-01

    Full Text Available Introduction: Chronic exposure to Portland cement dust has been reported to lead to greater prevalence of various clinical conditions (includes both respiratory and non-respiratory. These conditions are consistently associated with the degree and duration of exposure. Regular use of appropriate personal protective equipment if made available at the work site could protect the cement factory workers from adverse health effects. Objective: To study the morbidity profile of the cement factory workers. Type of Study: Retrospective cohort study. Material and Methods: This study was conducted in the Portland Cement Factory in North Karnataka. Data was collected using predesigned questionnaire by personal interview method and clinical examination. A total of 64 male workers are randomly selected who are working in various departments like crushing, raw/cement mill, rotary kiln and packing department. Equal number of unexposed controls was selected from the area atleast 5 kms from the factory and those who are not exposed to cement dust in the past, who are matched for age, Socio economic status and smoking with the exposed population. Statistical Analysis: Chisquare test for qualitative data and unpaired t test for quantitative data using Epi info. Results: A total of 64 male workers and equal number of matched controls who are not exposed to the cement dust were included in the study. Among exposed maximum of 36% were employed in Crushing department, 25% each in Packing and cement/raw mill. Systolic and Diastolic blood pressure was found to be higher among the exposed, which is statistically highly significant (p<0.001. There is significant increase in weight among exposed (p<0.001. Maximum 29(45.3% of the workers had stuffy nose and epistaxis when compared to unexposed with Relative risk(RR of 2.6, followed by Dermatological complaints and lower respiratory complaints with RR of 2.18 and 2.3 respectively. Conclusion: Personal protective equipment

  9. 水泥窑协同处置沼渣能效分析%Analysis of energy efifciency of biogas residue disposal in cement kilns

    Institute of Scientific and Technical Information of China (English)

    龚子亮; 曹玉书

    2015-01-01

    The collaborative disposal of sludge residue using cement kiln,and the process monitoring, energy efficiency of data collection and analysis and evaluation,analysis of cement kiln waste disposal collaborative social market prospects.%利用水泥窑对污泥沼渣进行协同处置,并对此过程进行监测,对能效数据进行收集整理并分析评价,分析水泥窑协同处置社会废弃物的市场前景。

  10. Dioxin-like pcb emissions from cement kilns during the use of alternative fuels.

    Science.gov (United States)

    Richards, Glen; Agranovski, Igor E

    2017-02-05

    The substitution of combustion fuels in cement plants is increasing throughout many countries, and its individual performance is constantly assessed against strict regulatory standards. For cement plants within Australia, normal operations remain to use petroleum coal as the dominate energy source at the precalciner, avoiding the opportunity to reduce carbon-based resources and pollutant emissions (such as carbon dioxide, oxides of nitrogen, persistent organic pollutants) whilst providing the necessary energy needs through resource recovery. This paper presents stack emission monitoring of health-critical dl-PCB (dioxin-like polychlorinated biphenyl) congeners during the substitution of alternative fuels at ten Australian cement plants, and to distinguish statistical similarities between other key pollutants (such as polychlorinated dibenzo-p-dioxins and furans (PCDD-F) and hydrogen halogens) and amongst the fuels used. Sampling of plant emissions was performed during normal operations (as baseline trials) and with the varied substitution rates of waste oil, solvents, chipped wood, refuge waste, carbon dust, shredded tyres and black sand (as experimental trials). The extraction of field and analytical data during these trials allowed for determining the total and individual unit mass of dl-PCB and PCDD-F isomers, standardised to 10% O2 and to World Health Organization (2005) toxicity equivalence (TEQ) values. The findings showed waste co-incineration during cement operations does reduce health-critical congeners of dioxins and dl-PCBs whilst providing the necessary energy and calcination needs. Experimental trials showed all dl-PCBs and PCB TEQ are below the internationally regulated Stockholm Convention article of 10pg TEQ/Nm(3). In several cases, an increased rate of substituted fuel also identified a consistent reduction to baseline dl-PCBs. The distribution of toxic isomers (TCDD-F and PeCDD-F) were shown to be predominate during waste oil, wood chips, and

  11. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    Directory of Open Access Journals (Sweden)

    Daniel Véras Ribeiro

    2009-03-01

    Full Text Available Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP, which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in terms of microstructure (SEM, mechanical strength and capillary water absorption was verified. The results obtained proved very satisfactory for the use of this waste as an additive in magnesium phosphate mortars.

  12. Exposure to cement dust at a Portland cement factory and the risk of cancer.

    Science.gov (United States)

    Vestbo, J; Knudsen, K M; Raffn, E; Korsgaard, B; Rasmussen, F V

    1991-01-01

    The relation between exposure to cement dust and cancer was examined in a population of 546 cement workers and a reference population of 858 randomly sampled men of similar age and area of residence. In 1974 all men gave lifelong occupational and smoking histories; information on incidence of cancer in the period 1974-85 was obtained from the Danish Cancer Registry. No increased risk of overall cancer was found among cement workers. Among men with more than 20 years exposure to cement dust, 14 cases of respiratory cancer were observed (observed/expected (O/E) 1.52, 95% confidence interval (95% CI) 0.90-2.57) when compared with all Danish men. Men with 1-20 years exposure had O/E 1.14 (95% CI 0.59-2.19) based on nine cases of cancer. After excluding all men with documented exposure to asbestos during employment in an asbestos cement factory no increased risk of overall cancer or respiratory cancer was found among cement workers compared with white collar workers from the local reference population, using a Cox regression model controlling for age and smoking habits. Relative risks were 0.5 (95% CI 0.1-1.5) and 1.0 (95% CI 0.4-2.6) for men with 1-20 and more than 20 years of exposure to cement dust respectively compared with white collar workers. PMID:1772795

  13. Co-firing of refuse derived fuels with coals in cement kilns: combustion conditions for stable sintering

    Energy Technology Data Exchange (ETDEWEB)

    Haas, J.; Weber, R. [Clausthal University of Technology, Clausthal Zellerfeld (Germany)

    2010-12-15

    Usage of refuse derived fuels (RDFs) in cement clinker processes has grown considerably in the last decade. It has been demonstrated that RDFs can partially substitute fossil fuels without compromising clinker quality. The paper considers RDF properties which are essential for stabilisation of the sintering zone in the clinker burning process. An energy replacement indicator, defined as the RDF thermal input to the fossil fuel thermal input ratio, is used. Comminution of RDF to particle scales of pulverised fuel is economically not yet feasible and RDF is burnt at particle sizes in the order of several millimetres. Therefore, RDF combustion rates are orders of magnitudes smaller if compared to pulverised coal combustion rates. This shifts the flame zone downstream the rotary kiln and flame temperatures are reduced. A simple kiln combustion model has been used to examine the effects of RDF properties on sintering zone temperatures. Refuse derived fuels with calorific values below 20 MJ kg{sup -1} and coarse particle sizes burn at adiabatic temperatures below 2000{sup o}C. To compensate for this, the energy replacement ratio has to be increased to 114%. Calculations have shown several options to increase gas temperatures in sintering zones. The most effective would be the comminution of RDFs to pulverised fuel sizes. In this case, a further reduction of the RDF calorific value would be acceptable.

  14. Quantification of the Reduced Environmental Impacts with Use of Co-Processing in Cement Kilns in India

    Directory of Open Access Journals (Sweden)

    Ankur Tiwary

    2014-10-01

    Full Text Available Coupled with resource conservation and reduced carbon emissions, co-processing technology is a preferable alternative for sound and environmental friendly waste disposal over incinerators & non-scientific methods. It is not only solution to the waste disposal menace, but also reduces burden on secured landfills & TSDFs. Apart from using energy and material value of wastes, co-processing not only fixes the inorganic content of the wastes within the clinker, but also, it destroys the wastes completely due to high temperature and long residence time, avoiding need of further processing as in case of incineration. Trial run identifies wastes suitable for co-processing, source emission monitoring assesses environmental impacts and the quantification of reduced environmental impacts gives a clear picture of actual benefits of co-processing. The results show that the suggested process is efficient, economized and environmental friendly, particularly for a populated country, such as India, as there was no adverse effect on quality of cement, stack emission and air quality of environment due to co-processing of variety of identified wastes in cement kiln. Also, the quantified data of coal saved, CO2 emissions reduced & landfill volume avoided by the waste utilization will help in convincing all the stakeholders that co-processing of waste is the best environmentally sound technology for waste disposal. DOI: http://dx.doi.org/10.5755/j01.erem.69.3.6736

  15. Utilization of waste heat from rotary kiln for burning clinker in the cement plant

    OpenAIRE

    2016-01-01

    Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO2 emissions reduction in addition to the recover...

  16. Utilizing TEMPO surface estimates to determine changes in emissions, community exposure and environmental impacts from cement kilns across North America using alternative fuels

    Science.gov (United States)

    Pegg, M. J.; Gibson, M. D.; Asamany, E.

    2015-12-01

    A major problem faced by all North American (NA) Governments is managing solid waste from residential and non-residential sources. One way to mitigate the need to expand landfill sites across NA is waste diversion for use as alternative fuel in industries such as cement manufacture. Currently, waste plastic, tires, waste shingles and other high carbon content waste destined for landfill are being explored, or currently used, as an alternative supplemental fuels for use in cement kilns across NA. While this is an attractive, environmentally sustainable solution, significant knowledge gaps remain in our fundamental understanding of whether these alternative fuels may lead to increased air pollution emissions from cement kilns across NA. The long-term objective of using TEMPO is to advance fundamental understanding of uncharacterized air pollution emissions and to assess the actual or potential environmental and health impacts of these emissions from cement kilns across NA. TEMPO measurements will be made in concert with in-situ observations augmented by air dispersion, land-use regression and receptor modelling. This application of TEMPO follows on from current research on a series of bench scale and pilot studies for Lafarge Canada Inc., that investigated the change in combustion emissions from various mixtures of coal (C), petroleum coke (PC) and non-recyclable alternative fuels. From our work we demonstrated that using an alternative fuel mixture in a cement kiln has potential to reduce emissions of CO2 by 34%; reduce NOx by 80%, and reduce fuel SO2 emissions by 98%. We also provided evidence that there would be a significant reduction in the formation of secondary ground-level ozone (O3) and secondary PM2.5 in downwind stack plumes if alternative waste derived fuels are used. The application of air dispersion, source apportionment, land use regression; together with remote sensing offers a powerful set of tools with the potential to improve air pollution

  17. Case study of an MBT plant producing SRF for cement kiln co-combustion, coupled with a bioreactor landfill for process residues.

    Science.gov (United States)

    Grosso, Mario; Dellavedova, Stefano; Rigamonti, Lucia; Scotti, Sergio

    2016-01-01

    The paper describes the performances of the energy recovery pathway from the residual waste based on the production of a Solid Recovered Fuel (SRF) to be exploited via co-combustion in a cement kiln. The SRF is produced in a single stream Mechanical-Biological Treatment plant, where bio-drying of the waste is followed by mechanical refining in order to fulfil the quality requirements by the cement kilns. Peculiar of this MBT is the fact that sorting residues are disposed in a nearby landfill, managed according to a bioreactor approach, where landfill gas is collected for electric energy recovery. A detailed mass and energy balance of the system is presented based on one year operational data, followed by its Life Cycle Assessment. Results show that the system is energetically and environmentally effective, with most of the impacts being more than compensated by the savings of materials and energy. Major role in determining such outcome is the displacement of petcoke in the cement kiln, both in terms of its fossil CO2 emissions and of its life cycle impacts, including the trans-oceanic transport. To check the robustness of the results, two sensitivity analyses are performed on the landfill gas collection efficiency and on the avoided electric energy mix.

  18. 水泥窑处理工业废物的工厂实验研究%Plant Test of Industrial Waste Disposal in a Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    刘阳生; 韩杰; 白庆中

    2003-01-01

    Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for thetreatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes wereco-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal (especially solid wastedisposal) on the quality of clinker and the concentration of pollutants in air emission. Experimental results showthat (1) waste disposal does not affect the quality of clinker and fly ash, and fly ash after the IW disposal can still beused in the cement production, (2) heavy metals from IW are immobilized and stabilized in the clinker and cement,and (3) concentration of pollutants in air emission is far below than the permitted values in the China NationalStandard-Air Pollutants Emission Standard (GB 16297-1996).

  19. Pollution and Prevention of Pb during Cement Calcination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Emission pollution and prevention measures of Pb during cement calcination were discussed. The content of Pb and the variation of composition were explored by means of atomic absorption spectroscopy (AAS) and X-ray diffraction. The results show that a number of Pb emits during cement calcination, F and C1 promote the emission of Pb, and Pb is enriched in kiln dust. The smaller the particle of kiln dust, the higher the content of Pb. When utilizing the raw materials with a high content of Pb, a more efficient dust collector should be used and the kiln dust should be used as the addition of cement. Pb in clinker is enriched in the intermediate phase. The reduction of silica modulus is useful to increase the solidification content of Pb in clinker. The solidification content of Pb in calcium sulphoaluminate mineral is higher than that in calcium aluminate mineral.

  20. Experimental research on mathematical modelling and unconventional control of clinker kiln in cement plants

    Science.gov (United States)

    Rusu-Anghel, S.

    2017-01-01

    Analytical modeling of the flow of manufacturing process of the cement is difficult because of their complexity and has not resulted in sufficiently precise mathematical models. In this paper, based on a statistical model of the process and using the knowledge of human experts, was designed a fuzzy system for automatic control of clinkering process.

  1. Characteristics of ammonia emission during thermal drying of lime sludge for co-combustion in cement kilns.

    Science.gov (United States)

    Liu, Wei; Xu, Jingcheng; Liu, Jia; Cao, Haihua; Huang, Xiang-Feng; Li, Guangming

    2015-01-01

    Thermal drying was used to reduce sludge moisture content before co-combustion in cement kilns. The characteristics of ammonia (NH3) emission during thermal drying of lime sludge (LS) were investigated in a laboratory-scale tubular dry furnace under different temperature and time conditions. As the temperature increased, the NH3 concentration increased in the temperature range 100-130°C, decreased in the temperature range 130-220°C and increased rapidly at >220°C. Emission of NH3 also increased as the lime dosage increased and stabilized at lime dosages>5%. In the first 60 min of drying experiments, 55% of the NH3 was released. NH3 accounted for about 67-72% of the change in total nitrogen caused by the release of nitrogen-containing volatile compounds (VCs) from the sludge. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy revealed that the main forms of nitrogen in sludge were amides and amines. The addition of lime (CaO) could cause conversion of N-H, N-O or C-N containing compounds to NH3 during the drying process.

  2. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner)

    OpenAIRE

    Dr.(Mrs).Suruchi Gupta; Sarika Sharma

    2013-01-01

    In Nokha(Bikaner) cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotomete...

  3. Partial Replacement of Cement with Marble Dust Powder

    Directory of Open Access Journals (Sweden)

    Mr. Ranjan Kumar

    2015-08-01

    Full Text Available The waste generated from the industries cause environmental problems. Hence the reuse of this waste material can be emphasized. MarbleDust Powder (MDP is a developing composite materialthatwillallow the concrèteindustry to optimisemateriel use, generateeconomicbenefits and build structures thatwillstrong, durable and sensitive to environnement. MDP is by-product obtained during the quarrying process from the parent marble rock; which contains high calcium oxide content of more than 50%. The potential use of MDP can be an ideal choice for substituting in a cementitious binder as the reactivity efficiency increases due to the presence of lime. In this research work, the waste MDP passing through 90 microns,has used for investigating of hardened concrete properties. Furthermore, the effect of different percentage replacement of MDP on the compressive strength, splitting tensile strength (indirect tensile strength&flexural strength has been observed. Inthis experimental study, the effect of MDP in concrete on strength ispresented. Five concrete mixtures containing 0%, 5%, 10%, and 20% MDP as cement replacement by weightbasis has been prepared. Water/cement ratio (0.43 was kept constant, in all the concretemixes. Compressive strength, split tensile strength & flexural strength of the concrete mixtures has been obtainedat 7 and 28 days. The results of the laboratory work showed thatreplacement of cement with MDP increase, upto 10% for compressive strength,&upto 15% for split tensilestrength &flexural strength of concrete.

  4. The emission of particulate matters and heavy metals from cement kilns – case study: co-incineration of tires in Serbia

    Directory of Open Access Journals (Sweden)

    Dušan Todorović

    2010-09-01

    Full Text Available Co-incineration of wastes started more than 20 years ago. In the last 10 years, the use of alternative fuels in the cement industry is continuously increasing. The use of solid wastes in cement kilns is one of the best technologies for a complete and safe destruction of these wastes, due to the fact that there is a simultaneous benefit of destroying wastes and getting the energy. However, particulate matters (PM and gaseous chemicals emitted from a source into the environment could be directly transmitted to humans through air inhalation. Therefore, for accurate health risk estimation, the emission of pollutants must be determined. In this work, the analysis of the emission of different pollutants when replacing partially the fuel type used in a cement kiln is done. PM, PM10, heavy metals and inorganic pollutants are analyzed. The methods used for sampling and analysis are the standard methods suggested by the EU regulations for stack analysis. Experimental results have shown the encouraging results: in particular clinker characteristics were unmodified, and stack emissions (NOx, SO2 and CO mainly were in the case of tires, slightly incremented but remaining almost always below the law imposed limits, and in some cases were even decreased.

  5. Effect of duration of exposure to cement dust on respiratory function of non-smoking cement mill workers.

    Science.gov (United States)

    Meo, Sultan Ayoub; Al-Drees, Abdul Majeed; Al Masri, Abeer A; Al Rouq, Fawzia; Azeem, Muhammad Abdul

    2013-01-16

    This study aimed to determine the effect of long term exposure to cement dust on lung function in non-smoking cement mill workers. This is a cross-sectional study of respiratory functions. Spirometry was performed in 100 apparently healthy volunteers; 50 non-smoking cement mill workers and 50 non-smoking un-exposed subjects. Based on the duration of exposure, cement mill workers were divided into three groups, less than 5, 5-10 and greater than 10 years. All subjects were individually matched for age, height, weight, and socioeconomic status. Pulmonary function test was performed by using an electronic spirometer. Significant reduction was observed in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV(1)), Peak Expiratory Flow (PEF) and Maximal Voluntary Ventilation in cement mill workers who had been working in the cement industry for more than 10 years compared to their matched un-exposed group. Lung functions in cement mill workers were significantly impaired and results show a long term duration response effect of years of exposure to cement dust on lung functions.

  6. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner

    Directory of Open Access Journals (Sweden)

    Dr.(Mrs.Suruchi Gupta

    2013-08-01

    Full Text Available In Nokha(Bikaner cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotometer. From the above study it is clear that in case of Sarvottam cement works only lead content was higher in all directions and depths than other two plants. At tiger and Nokha cement works contamination of lead was more over limited in the first 1 km except in east direction. Mobility of lead was relatively more on top soil than 20cm depth. Hexavalent chromium content in south western direction was more for Nokha cement. Whereas, it was more in east direction in case of tiger cement. This indicated influence of prevailing direction of wind on distribution of heavy metals present in cement dust.Heavy metal toxicity results in reduction in plant height, burning of leaf margins and tip, slow leaf growth and over all wilting of Prosopis cineraria, Pearlmillet and clusterbean plants, when this metal deposits in Human body results in genetic disorders. Electrostatic precipitator can be installed to reduce the cement dust emission.

  7. 电改袋技术在回转窑窑头烟气净化中的应用%Application of ESP Retroft to FF Technology in Rotary Kiln Back’s Flue Gas Cleaning System of New Dry Cement Process

    Institute of Scientific and Technical Information of China (English)

    章潮鸿

    2012-01-01

      在对水泥生产线篦冷机尾气除尘进行分析的基础上,提出了电除尘改袋式除尘的必要性,可有效控制新型干法窑烟尘和粉尘的排放浓度;针对具体案例的使用结果进行了阐述。%  The important point of environmental protection at the new dry cement kiln is that how to effectively control the concentration of dust emission under the new environmental standards in China. This paper puts forward the necessity of ESP retroft to FF technology based on the analysis on cement processing tail gas dedusting, and an introduction of the use result of specifc case concerned.

  8. 水泥窑炉协同处理城市垃圾研究进展%Research Progress of Cooperative Treatment Municipal Solid Waste in Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    陈国艳; 曾纪进

    2012-01-01

    Using the cement kiln to dispose of hazardous waste and municipal solid waste is one of the best many treatment methods to realize reduction, harmless and reclamation. The cement kiln burning waste can take advantage of the heat of waste to save fuels, and the ash after waste combustion can substitute materials. In addition, the CaO and the transitional clinker mineral can inhibit the adverse affects of hazardous substances, and can also reduce the emissions of dioxin and other harmful gases.%水泥窑炉处理危险废物和城市生活垃圾是众多处理方法中实现减量化、无害化和资源化最好的方法之一.水泥窑焚烧垃圾可以利用垃圾的热量节省燃料,同时垃圾燃烧后的灰渣可以替代原料.另外,CaO和过渡性熟料矿物对有害物质的不良作用有抑制作用,也可以减少二恶英等有害气体的排放.

  9. Cement Dust Exposure and Perturbations in Some Elements and Lung and Liver Functions of Cement Factory Workers

    Directory of Open Access Journals (Sweden)

    Egbe Edmund Richard

    2016-01-01

    Full Text Available Background. Cement dust inhalation is associated with deleterious health effects. The impact of cement dust exposure on the peak expiratory flow rate (PEFR, liver function, and some serum elements in workers and residents near cement factory were assessed. Methods. Two hundred and ten subjects (50 workers, 60 residents, and 100 controls aged 18–60 years were studied. PEFR, liver function {aspartate and alanine transaminases (AST and ALT and total and conjugated bilirubin (TB and CB}, and serum elements {lead (Pb, copper (Cu, manganese (Mn, iron (Fe, cadmium (Cd, selenium (Se, chromium (Cr, zinc (Zn, and arsenic (As} were determined using peak flow meter, colorimetry, and atomic absorption spectrometry, respectively. Data were analysed using ANOVA and correlation at p=0.05. Results. The ALT, TB, CB, Pb, As, Cd, Cr, Se, Mn, and Cu were significantly higher and PEFR, Fe, and Zn lower in workers and residents compared to controls (p<0.05. Higher levels of ALT, AST, and Fe and lower levels of Pb, Cd, Cr, Se, Mn, and Cu were seen in cement workers compared to residents (p<0.05. Negative correlation was observed between duration of exposure and PEFR (r=-0.416, p=0.016 in cement workers. Conclusions. Cement dust inhalation may be associated with alterations in serum elements levels and lung and liver functions while long term exposure lowers peak expiratory flow rate.

  10. Numerical Modeling of Rotary Kiln Productivity Increase

    OpenAIRE

    2013-01-01

    Rotary kilns are used in many industrial processes ranging from cement manufacturing to waste incineration. The operating conditions vary widely depending on the process. While there are many models available within the literature and industry, the wide range of operating conditions justifies further modeling work to improve the understanding of the processes taking place within the kiln. The kiln being studied in this work produces calcium aluminate cements (CAC). In a first stage of the pro...

  11. Impact of cement dust pollution on Cedrela fissilis Vell. (Meliaceae): A potential bioindicator species.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Lemos-Filho, José Pires; Paiva, Elder Antonio Sousa

    2016-09-01

    Considering the impacts caused to vegetation in the vicinity of cement factories, the aim of this study was to evaluate the impacts of cement dust on the structural organization and physiological/biochemical traits of Cedrela fissilis leaflets, a woody species native to tropical America. Plants were exposed to 2.5 or 5 mg cm-2 cement dust applied to the leaf surface, to the soil or simultaneously to the leaf surface and the soil.. Leaves of shoot-treated plants exhibited chlorosis, marginal and inter veins necrosis, diminished thickness, epidermal cells less turgid, cellular collapse, obstructed stomata, senescence, rolling and some abscission. In few cases, individual death was recorded. Cement dust-treated plants also presented decreased amount of photosynthetic pigments and iron (Fe) and increase in calcium (Ca) levels. The cement crust formed in leaves surface blocked from 30 to 50% of the incoming light and reduced the stomatal conductance and the potential quantum yield of photosystem II. Control or soil-treated plants did not exhibit morphophysiological changes throughout the experiment. The activity of superoxide dismutase, catalase and ascorbate peroxidase increased in leaves of plants upon treatment with 2.5 mg cm(-2) cement dust, independent of the site application. Overall, these results indicate that C. fissilis is highly sensitive to cement dust at the initial stage of development.

  12. Application of dynamic BP neural net in temperature control of cement rotary kiln%一种动态神经网络在水泥回转窑温度控制中的应用

    Institute of Scientific and Technical Information of China (English)

    张建民; 陈宏力; 魏秀兰

    2001-01-01

    A kind of dynamic neural net is introduced, and it is used for artificial temperature control of cement rotary kiln.%介绍了一种动态神经网络,并用此神经网络对水泥回转窑温度实行了仿真控制研究。

  13. The effect of various types of cement dust on sulphur dioxide oxidation in the air.

    Science.gov (United States)

    Vadjić, V; Gentilizza, M; Halle, R

    1988-07-01

    The effect of various types of cement dust on the behaviour of sulphur dioxide in the air was investigated on model systems in different experimental conditions.Experiments were carried out with PC-15z-45s (Portland-blast furnace cement containing 15% blast furnace slag), PC-25p-35s (Portland-pozzolan cement containing 25% pozzolan) and EFD (electrofilter dust).EFD most effectively removed SO2 from the air stream. The next efficacious was PC-15z-45s, whereas PC-25p-35s was the least efficient. The efficacy of cement dusts for SO2 removal from the air stream depended on their chemical and granulometric composition and in particular on the size of specific surface.The rate of reaction was also influenced by experimental conditions-relative humidity, the length of contact, that is, the flow rate of gaseous mixture through the reactor, and the amount of cement dust.The experimental data show that in the contact between SO2 and cement dust catalytic oxidation of SO2 to sulphates takes place. Sulphates remain bound to the surface, from which they cannot be thermally desorbed, but can be released by extraction in the Soxhlet apparatus.

  14. Preparation and Application of Special Silicon Mullite Brick for Cement Kiln%水泥窑用特种硅莫砖的研制及应用

    Institute of Scientific and Technical Information of China (English)

    刘振英; 姚峰

    2012-01-01

    以高铝矾土熟料、90碳化硅、棕刚玉为主要原料,添加红柱石粉、广西白泥等外加剂,通过合理的颗粒级配,采用高压成型、高温烧成等方法,制备出水泥窑用特种硅莫砖,并研究了烧成后试样的体积密度、气孔率、强度、微观结构和耐磨性.结果表明:添加6%红柱石粉在1420℃制备的硅莫砖的性能最优,其体积密度为2.74 g/cm3,抗热震性30次,磨损量为1.06 cm3,热导率为1.65 W/(m·K),耐压强度高达159 MPa,在5000 t/d水泥回转窑过渡带上使用该产品,寿命可达一年以上,这是由于窑简体外表面温度比使用镁尖晶石砖平均降低80℃以上,极为有效地延长了该砖衬的使用寿命.%Special silicon mullite brick for cement kiln was prepared by the production technology of proper particle size grading,high pressure pressing and high temperature sintering using bauxite clinke,90 silicon carbide and brown alundum as raw materials, and andalusite powder and guangxi white clay as additives. The bulk density, apparent porosity, strength, microstructure and abrasion resistance of the sintered materials were investigated. The results showed that the sample sintered at 1420 t whose andalusite powder content was 6% was of good properties on bulk density of 2. 74 g/cm3, thermal conductivity of 1.65 W/ ( m · K ) , thermal shock resistance of 30 times, abrasion volume loss of 1.06 cm3 and compressive strength of 159 Mpa. When the brick were used in the transition zone of cement kiln,the service life of it was more than a year and a half .which was due to the cement kiln surface temperature of special silicon mullite brick was lower (average decreasing 80 X.) than that of magnesium spinel brick and the service life of special silicon mullite brick was prolonged effectively.

  15. Process development for utilizing asbestos cement waste in rotary kilns for the cement industry. Final report; Erarbeitung eines Verfahrens zur stofflichen Verwertung von zementgebundenen Asbestprodukten in Drehrohroefen fuer die Zementindustrie. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, R.; Kieser, J.; Kraehner, A.

    1999-11-01

    The law for recycling and waste demands the utilization also for waste of asbestos cement (ac). The procedure of thermal utilization of ac in the flame of a rotary cement kiln was developed and patented by the research institute IBU-tec Weimar, Germany. The ac-material has to be pre-pulverized and grinded to a degree of fineness of R{sub 90}<15%. Considerations of safety engineering lead to the idea of common fine grinding of old oil (oo) and ac. This new procedure was searched in FuE-project in 1998/99 (financial support by BMBF). A mash of ac and oo was generated as a utilization product ready for firing which was injected into the flame of the rotary cement kiln. This particles of ac smelt to spherical shaped particles at a temperature above 1500 C. They were utilized by clinker formation. The material and gas stream leaving the kiln does not contain fibres of asbestos. This was demonstrated in a small equipment burning test. The industrial realization concerning cement plant Ruedersdorf, near Berlin, was searched, technologically described and safety engineeringly and financially assessed by a project study. Process-technical and financial advantages were seen for the dry fine grinding. The wet fine grinding with old oil could be used in cement plants using old oil as fuel. (orig.) [German] Das Kreislaufwirtschafts- und Abfallgesetz (1994) fordert u.a. die stoffliche Verwertung auch fuer Asbestzementabfaelle (AZ). Das vom Institut fuer Baustoff- und Umweltschutz-Technologie Weimar 1995 entwickelte und patentierte Verfahren zur thermischen Verwertung von AZ in der Flamme eines Zementdrehrohrofens erfuellt diese Forderung. Das AZ-Material muss vorzerkleinert und bis zur Rohmehlfeinheit (R{sub 90}<15%) feingemahlen werden. Sicherheitstechnische Ueberlegungen fuehrten zu der Idee, die Feinmahlung zusammen mit Altoel (AOe) zu erproben. Diese Verfahrensvariante wurde im Rahmen eines FuE-Projektes 1998/99 untersucht (finanzielle Foerderung durch das BMBF). Als

  16. Effect of cement kiln dust and gamma irradiation on the ultrasonic parameters of HMO borate glasses

    Science.gov (United States)

    Abd elfadeel, G.; Saddeek, Yasser B.; Mohamed, Gehan Y.; Mostafa, A. M. A.; Shokry Hassan, H.

    2017-03-01

    Glass samples with the chemical formula x CKD-(100 - x) (5Na2O-65 B2O3-9 Bi2O3-21PbO), (0 ⩽ x ⩽ 32 mol%) were prepared. The density and the ultrasonic estimations of the investigated glasses were analyzed at room temperature before and after the impact of two dosages of gamma irradiation to study the effect of both CKD and gamma radiation. It was found that the density, and the ultrasonic parameters are sensitive to the variety of the content of CKD and the effect of γ-radiation. Replacement of oxides with higher atomic weights such as Bi2O3 and PbO by CKD decreases the density. Analysis of the behavior of the ultrasonic parameters demonstrates that creation of CaO6 and SiO4 on one hand and an alternate transformation between BO4 and BO3 structural units, on the other hand, affect the increase of the ultrasonic velocities and the elastic moduli. Moreover, the density and the ultrasonic parameters decrease somewhat with the increase of the doses of γ-irradiation. The variations of the previous physical parameters can be referred to the creation of radiation imperfections, which occupied the voids inside the glass structure.

  17. Improve the capability for waste heat power generation of cement kiln%如何提高水泥窑余热发电能力

    Institute of Scientific and Technical Information of China (English)

    蒋向辉

    2011-01-01

    通过分析研究余热电站的主要问题,采取技改措施提高机组的主参数,锅炉的旁通挡板改进,提高锅炉换热效率,加强发电系统与窑系统操作配合等提高水泥窑纯低温余热发电的能力。%Through the main problems in my company to take measures to improve the power output transformation of generating capacity of cement kiln 。1、Improve the main parameters of the generator;2、Improved boiler bypass valve;3、Improve the efficiency of the boiler

  18. Cement dust pollution induces toxicity or deficiency of some essential elements in wild plants growing around a cement factory.

    Science.gov (United States)

    Mutlu, Salih; Atici, Ökkes; Gülen, Yasir

    2013-06-01

    In the present study, it was aimed to determine the effects of cement dust pollution on contents of some significant essential elements (P, S, K, Ca, Fe and Cl) in wild plants (Medigago varia, Anchusa leptophylla, Euphorbia orientalis, Lactuca serriola, Artemisia spicigera, Crambe orientalis, Convolvulus sepium and Senecio vernalis) using wavelength-dispersive spectrometer X-ray fluorescence technique. Plant samples were collected from different locations around a cement factory which is located at Askale about 50 km from Erzurum (Turkey). The element contents in the plant specimens that existed in both 0-100 m (dense dusted) and 2000 m (undusted) areas were compared. P, S, K and Cl contents were found to be high in the plants growing in areas 0-100 m from the cement factory, compared to same plants at 2000 m far from the factory. However, Ca and Fe contents were determined to be low in plants growing in 0-100 m area from the factory. Results of the study can contribute to understand how mineral deficiency and toxicity lead to detrimental effects on plant growth and development in the fields contaminated by cement dust.

  19. Ecophysiological and ultrastructural effects of dust pollution in lichens exposed around a cement plant (SW Slovakia).

    Science.gov (United States)

    Paoli, Luca; Guttová, Anna; Grassi, Alice; Lackovičová, Anna; Senko, Dušan; Sorbo, Sergio; Basile, Adriana; Loppi, Stefano

    2015-10-01

    The study investigated the ecophysiological and ultrastructural effects of dust pollution from a cement industry in the lichen species Evernia prunastri and Xanthoria parietina, which were exposed for 30, 90 and 180 days around a cement mill, two quarries, and inhabited and agricultural sites in SW Slovakia. The results showed that dust deposition from quarrying activities and cement works at the cement mill (mainly enriched in Ca, Fe and Ti) significantly affected the photosynthetic apparatus of E. prunastri (sensitive to dust and habitat eutrophication), while X. parietina (tolerant to dust and habitat eutrophication) adapted to the new environment. The length of the exposure strongly affected the vitality of the mycobiont (measured as dehydrogenase activity) in transplanted lichens. Dust deposition led to ultrastructural alterations, including lipid droplets increase, swelling of cellular components, thylakoid degeneration and sometimes plasmolysis, which, on the whole, gave the cells an aged appearance. Photosynthetic parameters deserve further attention as potential indicators for monitoring early biological symptoms of the air pollution caused during cement production.

  20. Biomonitoring spatial and temporal impact of atmospheric dust from a cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Branquinho, Cristina [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal); Universidade Atlantica, Antiga Fabrica da Polvora de Barcarena, 2745-615 Barcarena (Portugal)], E-mail: cmbranquinho@fc.ul.pt; Gaio-Oliveira, Gisela; Augusto, Sofia; Pinho, Pedro; Maguas, Cristina; Correia, Otilia [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal)

    2008-01-15

    The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation. - Biomonitoring Spatial and Temporal dust emissions in dry climates.

  1. Biomonitoring Study of Heavy Metals in Blood from a Cement Factory Based Community

    OpenAIRE

    Bank M.S.; Spengler J.D.

    2014-01-01

    Little is known about the effects of cement factory pollution, emissions, and kiln dust on contaminant exposure in human populations, including school environments, in close proximity to these point sources. In Ravena, New York, USA and vicinity, environmental pollution from a local cement plant is considered significant and substantial according to the United States Environmental Protection Agency’s Toxic Release Inventory, published in 2006, 2007, and 2010. We hypothesized that cement facto...

  2. Development of electro fused aggregates for use in refractories for the burning zone of cement kilns; Desenvolvimento de agregados eletrofundidos para utilizacao em refratarios para a zona de queima de fornos de cimento

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Luis Leonardo Horne Curimbaba

    2006-07-01

    Electro fused aggregates are largely used in refractory production due to the better performance reached when they are employed. In this work electro fused aggregates were designed for application in refractories for the burning zone of cement kilns. Initially reaction evaluation was conducted aiming the identification of the most prone refractory systems when single refractory phases react with Portland cement phases at high temperatures. In the next step, raw materials of the best refractory systems were electro fused to generate different aggregate compositions. The electro fused aggregates properties were evaluated and the classified ones were used to produce refractory bricks for the burning zone of cement kilns. General characteristics of these bricks were measured and compared with a standard magnesia-spinel refractory. Aggregates of the system Mg O - TiO{sub 2} - Ca O, more specifically aggregates belonged to the compatibility triangle Mg O - Mg{sub 2}TiO{sub 4} - CaTiO{sub 3}, showed suitable characteristics for development of refractories for the burning zone cement kilns. (author)

  3. Characteristics of mercury cycling in the cement production process.

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Wu, Qingru; Hao, Jiming

    2016-01-25

    The mercury cycling caused by dust shuttling significantly increases the atmospheric emissions from cement production. A comprehensive understanding of this mercury cycling can promote the development of mercury emission control technologies. In this study, the characteristics of mercury cycling in the cement production process were first investigated. Furthermore, the mercury enrichment and effects of dust treatment were evaluated based on the field tests conducted in two Chinese cement plants. The mercury cycling between the kiln system and the raw mill system was the most important aspect and contributed 57-73% to the total amount of mercury emitted from the kiln system. Mercury emitted from the kiln system with flue gas was enriched as high as 3.4-8.8 times in the two tested plants compared to the amount of mercury in the raw materials and coal due to mercury cycling. The mercury enrichment can be significantly affected by the proportion of mercury cycled back to the kiln system. The effects of dust treatment were evaluated, and dust treatment can efficiently reduce approximately 31-70% of atmospheric mercury emissions in the two plants. The reduction proportion approximately linearly decreased with the proportion of mercury removed from the collected dust.

  4. Cement dust exposure-related emphysema in a construction worker

    Directory of Open Access Journals (Sweden)

    V Karkhanis

    2011-01-01

    Full Text Available Although, smoking is considered the most important predisposing factor in development of emphysema; environmental exposures also play an important role. There have been several studies on work related respiratory symptoms and ventilatory disorders among employees of cement industry. We report a case of cement exposure related emphysema in 75 years old woman construction worker.

  5. Leaf structural traits of tropical woody species resistant to cement dust.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

    2016-08-01

    Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities.

  6. 利用水泥窑协同处置污泥对熟料的影响%Effect of Co-disposal of Sewage Sludge in Cement Kiln on Cement Clinker

    Institute of Scientific and Technical Information of China (English)

    张智; 李舒扬; 周黔生; 梅龙云; 陆磊; 陈杰云

    2012-01-01

    Co-disposal of sewage sludge in cement kiln is an economic and feasible method of resource utilization. An appropriate ratio of sewage sludge without drying replaced cement as a raw material. The mixture was pumped into the smoke chamber at the end of the rotating kiln by the sludge pump and calcined into cement clinker using high temperature in the kiln. The physical properties and mineral composition of the cement clinkers produced with and without sludge were compared and analyzed to discuss the effect of adding sludge. The result showed that all the indexes of the cement clinker produced with sludge met the national standard. Except for consistency, there was no evident variation in particle fineness and setting time. The 28-d compressive strength and breaking strength were increased evidently, and the stability was improved. Among the main minerals of cement clinker, tricalcium silicate was increased dramatically. This was the primary cause of the increase in 28-d compressive strength and break- ing strength. Meanwhile, dicalcium silicate was decreased, and tricalcium aluminate and brownmillerite showed no evident variation. Adding an appropriate amount of sludge is beneficial to the cement clinker.%利用水泥窑协同处置污水厂污泥,是一种经济、可行的资源化利用方式.重庆富皇水泥(集团)有限公司用未经干化的污水厂污泥,以合适的比例替代部分水泥生产原材料,用污泥泵直接喷入回转窑窑尾烟室内,利用水泥窑的高温煅烧成熟料.对比分析了掺加污泥前后水泥熟料的物理性能和矿物组成,探讨掺加污泥对其影响.结果表明,掺加污泥后水泥熟料的各项指标均满足国家标准,除稠度外,细度、凝结时间均无明显变化,28 d抗压强度和抗折强度有明显增加,安定性也有所增强.水泥熟料的主要矿物中,C3S含量呈极显著增加趋势,这是28 d强度明显增加的主要原因;C2S含量明显减少,而C3A和C4AF含量没有明

  7. Emissions of metals and polychlorinated dibenzo(p)dioxins and furans (PCDD/Fs) from Portland cement manufacturing plants: inter-kiln variability and dependence on fuel-types.

    Science.gov (United States)

    Zemba, Stephen; Ames, Michael; Green, Laura; Botelho, Maria João; Gossman, David; Linkov, Igor; Palma-Oliveira, José

    2011-09-15

    Emissions from Portland cement manufacturing facilities may increase health risks in nearby populations and are thus subject to stringent regulations. Direct testing of pollutant concentrations in exhaust gases provides the best basis for assessing the extent of these risks. However, these tests (i) are often conducted under stressed, rather than typical, operating conditions, (ii) may be limited in number and duration, and (iii) may be influenced by specific fuel-types and attributes of individual kilns. We report here on the results of more than 150 emissions-tests conducted of two kilns at a Portland cement manufacturing plant in Portugal. The tests measured various regulated metals and polychlorinated dibenzo(p)dioxins and furans (PCDD/Fs). Stack-gas concentrations of pollutants were found to be highly variable, with standard deviations on the order of mean values. Emission rates of many pollutants were higher when coal was used as the main kiln fuel (instead of petroleum coke). Use of various supplemental fuels, however, had little effect on stack emissions, and few statistically significant differences were observed when hazardous waste was included in the fuel mix. Significant differences in emissions for some pollutants were observed between the two kilns despite their similar designs and uses of similar fuels. All measured values were found to be within applicable regulatory limits.

  8. Peroxidase activity, soluble proteins and chlorophyll content in spruce (Picea abies L. Karst.) needles affected by cement dust

    OpenAIRE

    Cesar, Vera; Lepeduš, Hrvoje

    2001-01-01

    The correlation between the peroxidase activity, chlorophyll and soluble protein content as well as the changes in vascular bundle structure in Norway spruce (Picea abies L. Karst.) needles affected by cement dust were studied. In spite of the absence of any yellowing symptoms, a significantly lower chlorophyll content was measured in spruce needles affected by cement dust. Observed sieve cells distortions in needle samples indicated that spruce trees grown near the cement factory were Mg def...

  9. Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants

    OpenAIRE

    2012-01-01

    During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χfd), and temperature dependence of magnetic susceptibility. M...

  10. Effect of exposure to dust on lung function of cement factory workers.

    Science.gov (United States)

    Noor, H; Yap, C L; Zolkepli, O; Faridah, M

    2000-03-01

    Exposure to Portland cement dust has long been associated with the prevalence of respiratory symptoms and varying degrees of airway obstruction in man. Apart from respiratory diseases, it was also found to be the cause of lung and laryngeal cancer, gastrointestinal tumours and also dermatitis. This study was done to investigate the effect of dust exposure on ventilatory lung function of Portland cement factory workers in Rawang, Selangor. Spirometry tests of 62 male workers (exposed to total dust concentration of 10,180 micrograms/m3 and PM10 of 8049 micrograms/m3) and 70 subjects from UPM (exposed to mean total dust of 192 micrograms/m3 and PM10 of 177 micrograms/m3--controls) revealed significant differences in spirometry values between the groups. The workers showed i) significantly lower FEV1% and FEF25-75%, and higher FMFT, ii) reduced FEV1% with increasing level of dust exposure and iii) higher prevalence of respiratory symptoms. Therefore, we suggest that exposure to dust in the cement factory leads to higher incidence of respiratory symptoms and impaired lung function.

  11. Use of secondary fuels in rotary kilns of the cement industry; Einsatz von Sekundaerstoffen in Drehofenanlagen der Zementindustrie

    Energy Technology Data Exchange (ETDEWEB)

    Hoenig, V. [Forschungsinstitut der Zementindustrie, Duesseldorf (Germany)

    1998-09-01

    Most cement works in Germany use secondary materials for cement production or are planning to do so. Many of the materials in question, such as used tyres, have been recycled in an environmentally acceptable way for decades, and a large body of experience has accumulated on their use in the cement industry. In the cement industry secondary materials are understood to comprise secondary fuels as well as secondary raw materials. The latter have for some part replaced the natural raw materials used for burning cement clinker, the preliminary product of cement. By using used tyres, used oil and other waste materials as secondary fuels the cement industry has for decades contributed to an environmentally acceptable form of waste disposal. The use of secondary materials has also enabled the cement industry to improve its economic situation. In response to the enactment of the Materials Recycling Law the cement industry has during the past few years turned its attention to the utilisation of other waste materials. The criteria relevant to the cement industry`s choice of a waste material as secondary material lastly depends on the process-related side constraints attending the clinker burning process and the requirements on the burning process with regard to product quality and environmental acceptability. [Deutsch] Die meisten Zementwerke in Deutschland setzen bei der Zementherstellung Sekundaerstoffe ein oder planen ihren Einsatz. Fuer einige dieser Stoffe, wie z.B. Altreifen gilt, dass sie bereits seit Jahrzehnten umweltvertraeglich verwertet werden, so dass viele Erfahrungen ueber deren Einsatz in der Zementindustrie vorliegen. Unter Sekundaerstoffen werden in der Zementindustrie sowohl Sekundaerbrennstoffe wie auch Sekundaerrohstoffe verstanden. Letztere ersetzen teilweise die natuerlichen Rohstoffe, aus denen der Zementklinker, das Vorprodukt des Zements, gebrannt wird. Bezueglich der Sekundaerbrennstoffe traegt die Zementindustrie schon seit Jahrzehnten zu einer

  12. Hydration Characteristics and Immobilization of Cr (VI) in Slag Cement-CKD Pastes under Hydrothermal Treatment

    Institute of Scientific and Technical Information of China (English)

    M R Shatat; Gomaa A M Ali; M A Tantawy

    2015-01-01

    The effect of hydrothermal curing regimes on the hydration characteristics of slag cement containing different ratios of cement kiln dust has been studied. The samples for this study were combination of slag cement and cement kiln dust (5%-25%) without and with immobilization of 5% Cr (VI) by mass. Pastes were hydrothermally treated at 180℃ for different periods (2-24 h) in well closed stainless steel capsule. The hydration characteristics of these pastes were studied by measuring the compressive strength, bulk density, total porosity and combined water content. The findings were further supported by XRD and SEM analysis. The results indicated that the hydration characteristics of slag cement paste containing cement kiln dust 10% by mass were enhanced, especially at later ages (24 h) of hydration. That is due to the hydrothermal curing regimes of immobilized pastes accelerating hydration reactions and precipitation of CaCrO4, indicating that Cr (VI) can be solidiifed in the cement paste. This precipitation leads to pore formation in hydrated slag cement pastes.

  13. Lung function and long-term exposure to cement dust

    DEFF Research Database (Denmark)

    Rasmussen, F V; Borchsenius, L; Holstein, B

    1977-01-01

    In a cross-sectional epidemiological survey a selected group of former and present cement factory workers and a random sample of the corresponding urban population underwent dynamic spirometry. Based upon life experience the subjects were grouped into four occupational categories. Three hundred...... and one men were grouped as cement factory workers, 649 were grouped as blue collar workers, 218 as white collar workers and 102 men had predominantly been occupied in farming, forestry and fishing. On the average the investigated men had spent more than 75% of their total occupational life in their main...... throughout life had better ventilatory lung function than any of the other three occupational categories. No significant differences in lung function between cement factory workers and other blue collar workers with comparable smoking habits could be demonstrated by use of the maximal midexpiratory flow...

  14. Analysis of Potentially Toxic Metals in Airborne Cement Dust Around Sagamu, Southwestern Nigeria

    Science.gov (United States)

    Gbadebo, A. M.; Bankole, O. D.

    This study analyzed the concentration levels of potentially toxic and harmful elements contained in the airborne cement dust generated in the vicinity and farther away 500 m in the conventional four cardinal directions from the West African Portland Cement Company (WAPCO) factory mill, Sagamu. The results indicated that the concentration range of these toxic elements fall between 40.0 and 280,000 μg g-1 in the cement dust samples. Also, the concentration range of these toxic elements in 1 L of air samples varies between 0.01 μg g-1 and 29.92 μg L-1. The results generally show elevated concentrations of all the elements when compared with USA threshold limit of particulate mental concentration (e.g., Pb (1.5 g m-3); Cd (0.004-0.026 g m-3) in the air. These elements in the airborne cement dusts may pose a great threat to the health of plants, animals and residents in and around the factory and also to workers and visitors to the factory.

  15. Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants.

    Science.gov (United States)

    Magiera, Tadeusz; Gołuchowska, Beata; Jabłońska, Mariola

    2013-01-01

    During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χ(fd)), and temperature dependence of magnetic susceptibility. Mineralogical and geochemical analyses included scanning electron microscopy with energy dispersive spectroscopy, microprobe analysis and X-ray diffraction. The TMPs in fly ash from hard coal combustion have the form of typical magnetic spherules with a smooth or corrugated surface as well as a skeletal morphology, composed of iron oxides (magnetite, maghemite, and magnesioferrite) that occurred in the form of incrustation on the surface of mullite, amorphous silica, or aluminosilicate particles. The TMPs observed in fly ash from lignite combustion have a similar morphological form but a different mineralogical composition. Instead of magnetite and magnesioferrite, maghemite and hematite with lower χ values were the prevailing magnetic minerals, which explains the much lower magnetic susceptibility of this kind of ash in comparison with the ash from hard coal combustion, and probably results from the lower temperature of lignite combustion. Morphology and mineralogical composition of TMPs in cement dust is more diverse. The magnetic fraction of cement dust occurs mostly in the form of angular and octahedral grains of a significantly finer granulation (cement dust is calcium ferrite (CaFe(3)O(5)). The greatest impact on the magnetic susceptibility of cement dust results from iron-bearing additives (often waste materials from other branches of industry), which should be considered the most dangerous to the environment. Stoichiometric analysis of micro-particles confirmed

  16. Partial Replacement of Cement with Marble Dust Powder

    OpenAIRE

    Ranjan Kumar; Shyam Kishor Kuma

    2015-01-01

    The waste generated from the industries cause environmental problems. Hence the reuse of this waste material can be emphasized. MarbleDust Powder (MDP) is a developing composite materialthatwillallow the concrèteindustry to optimisemateriel use, generateeconomicbenefits and build structures thatwillstrong, durable and sensitive to environnement. MDP is by-product obtained during the quarrying process from the parent marble rock; which contains high calcium oxide content of more th...

  17. A RT-2神经网络在水泥窑况识别中的应用%APPLICATION OF ART-2 NEURAL NETWORK IN THE CEMENT ROTARY KILN-SATTUS

    Institute of Scientific and Technical Information of China (English)

    孙莉; 李琳琳

    2015-01-01

    The sintering process of the cement has the non-linearity,the multivariable,the closecoupling, and the big time lag characteristics.We analyze the influence of the wind,the coal,the material and the kiln speed in the rotary kiln system.The ART -2 neural network is used to recognise the change tendency of main craft parameter,and the intelligent recognition of the kiln -status is realized.The judgment of the kiln -status is completed by carring on the fuzzy to the secondary craft parameter and the inference by the IF-THEN sentence. The rensonable operation advice for kiln-status is thus given.Through the research of the ART-2 neural network, discover that the characteristic of ART-2 neural network is discovered to have the good effect in the recognition, and suits the recognition kiln-status of the rotary kiln system.%针对水泥烧成过程具有强耦合、大时滞、非线性、多变量等特性,分析风、煤、料与窑速对回转窑系统的影响,应用ART-2神经网络识别主要工艺参数的变化趋势,实现对窑况的智能识别;同时对次要工艺参数进行模糊化,以IF-THEN语句进行推理,完成窑况的判断,并针对窑况给出合理的生产操作建议。实验性运行表明,通过对ART-2神经网络的研究,其特性在识别中具有较好的效果,适合回转窑窑况的识别。

  18. Multi-Variable System Identification of Operating Point of Cement Rotary Kilns%水泥回转窑工作点的多变量系统辨识建模

    Institute of Scientific and Technical Information of China (English)

    张倩; 刘国华; 王群京; 李国丽

    2012-01-01

    The optimization modeling of the cement rotary kilns was investigated, as the precise mathematical model was needed in the realization of automatic control and optimization to the cement rotary kilns. As a high-temperature thermal equipment, the cement rotary kiln requires precise modeling because of its complex nonlinearity system. In order to solve the above problems, the time series models were introduced, and the Least Squares Method was applied to identify the parameters. The linear system models at and around the operating point were obtained, and the system modeling was realized though expert intelligent control software. Experimental results show that the normalized outputs of identified system fitts the real system outputs well, which demonstrates that the model can describe this multi-variable system at the operating point precisely and proves the effectiveness of the time series model identification algorithm.The optimization modeling of the cement rotary kilns was investigated, as the precise mathematical model was needed in the realization of automatic control and optimization to the cement rotary kilns. As a high-temperature thermal equipment, the cement rotary kiln requires precise modeling because of its complex nonlinearity system. In order to solve the above problems, the time series models were introduced, and the Least Squares Method was applied to identify the parameters. The linear system models at and around the operating point were obtained, and the system modeling was realized though expert intelligent control software. Experimental results show that the normalized outputs of identified system fitts the real system outputs well, which demonstrates that the model can describe this multi-variable system at the operating point precisely and proves the effectiveness of the time series model identification algorithm.%研究水泥回转窑优化建模问题,水泥回转窑自动控制优化的实现,需要以准确的数学模型作为基础.

  19. Experimental study of the mechanical stabilization of electric arc furnace dust using fluid cement mortars.

    Science.gov (United States)

    Ledesma, E F; Jiménez, J R; Ayuso, J; Fernández, J M; Brito, J de

    2017-03-15

    This article shows the results of an experimental study carried out in order to determine the maximum amount of electric arc furnace dust (EAFD) that can be incorporated into fluid cement-based mortars to produce mechanically stable monolithic blocks. The leaching performance of all mixes was studied in order to classify them according to the EU Council Decision 2003/33/EC. Two mortars were used as reference and three levels of EAFD incorporation were tested in each of the reference mortars. As the incorporation ratio of EAFD/cement increases, the mechanical strength decreases. This is due to the greater EAFD/cement and water/cement ratios, besides the presence of a double-hydrated hydroxide of Ca and Zn (CaZn2(OH)6·2H2O) instead of the portlandite phase (Ca(OH)2) in the mixes made with EAFD, as well as non-hydrated tricalcium silicate. A mass ratio of 2:1 (EAFD: cement-based mortar) can be added maintaining a stable mechanical strength. The mechanical stabilization process also reduced the leaching of metals, although it was not able to reduce the Pb concentration below the limit for hazardous waste. The high amount of EAFD mechanically stabilized in this experimental study can be useful to reduce the storage volume required in hazardous waste landfills.

  20. Use of RDF as a kiln fuel. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-10-01

    Refuse derived fuel (RDF) has been experimented with and/or proposed for use in kilns for the production of portland cement, lime, and expanded shale (a form of lightweight aggregate). Technological issues affecting the use of RDF in kilns are reviewed as are the results of trials in which RDF has been used as a kiln fuel. Three future research/demonstration projects for addressing the major unresolved issues are discussed. These projects are: a lime plant trial; a trial in a pre-calcining furnace; and an extended trial in a cement kiln.

  1. 回转水泥窑燃烧段混煤燃烧数值研究%Numerical Simulation on Combustion of Ble nded Coal in the Burning Region of Revolving Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    侯凌云; 张拥军; 傅维标

    2001-01-01

    For the blended coal composed of 70% anthracite and 30% bitumite,thi s paper si mulates the combustion processes inside the revolving cement kiln with a pulveri zed coal fired burner using a jet with velocity difference.A multiflui d mo del is used for two-phase turbulent flow.and a reaction and general model is u sed for combustio n processes of coal.The results show that the burner used in the revolving cemen t kiln can intensify combustion,furthermore,both the present burner and central high speed jet can restrain the expansion of pulverized coal and make flame not reach the slagging layer of the kiln.%对有反应湍流气粒两相流动采用双流体模型,对 煤粉燃烧过程采 用通用模型,首次针对70%无烟煤+30%烟煤的混煤燃料,将回转水泥窑筒体配有速差射 流煤粉燃烧器的燃烧过程进行了数值研究。结果表明,回转水泥窑中采用该型燃烧器能强化 燃烧,同时使煤粉的扩散受到约束,从而保证了火焰不致烧到窑皮。

  2. Technology Research on Municipal Domestic Waste Disposal Using Cement Kiln%利用水泥窑处置城市生活垃圾的技术研究

    Institute of Scientific and Technical Information of China (English)

    陈必鸣; 卢欢亮; 陈伟锋

    2011-01-01

    基于国内外利用水泥窑协同处置城市固体废物的工程实践,分析了生活垃圾作为替代燃料在水泥工业应用的影响因素,并进行利用水泥窑处置城市生活垃圾的技术可行性分析.%The influencing factors of using domestic waste as alternative fuel for cement industry were analyzed by means of introducing engineering practices of municipal solid waste co-disposal by applying cement kiln in domestic and overseas, and its technical feasibility analysis was carried out.

  3. Research on the characteristics of hydration of cement intermixed by the clinkers made in rotary kiln and shaft kiln%回转窑与立窑熟料混合配制水泥的水化特性研究

    Institute of Scientific and Technical Information of China (English)

    梁英; 程德铭; 冯庆革; 李浩璇

    2001-01-01

    The characteristics of hydration of cement intermixed by the clinkers made in rotary kiln and shaft kiln was studied under the same hydration condition through the analyses of hydration degree, chemical composition of liquid phase, XRD, DTA and SEM etc.. The results indicate that the hydration rate of the intermixed clinker at 1d was accelerated instead of being the simple sum of that of the starting clinkers. The intermix of cement did change the morphology of the hydrates while keeping the same types of hydrates. More needle and fibrous hydrates produced during the 1d hydration.%在相同的水化条件下,通过水化程度分析、水化液相分析、 XRD、 DTA和 SEM等方法研究了回转窑与立窑熟料混合配制的水泥的水化特性。结果表明,回转窑与立窑熟料混合后,其 1d水化速率并非两种水泥水化速率的简单加权,而是有明显加快;水泥浆体中的水化产物种类未改变,但改善了水化产物的形貌, 1d水泥浆体中生成了较多的针状和纤维状水化产物。

  4. 水泥回转窑自动控制系统中的控制算法研究%Study on Control Algorithm of Auto-control System for Cement Rotary Kiln

    Institute of Scientific and Technical Information of China (English)

    刘国华; 王群京; 张倩; 李国丽

    2012-01-01

    为了稳定水泥回转窑系统的温度,降低能耗,分析了整个烧成工况,提出分解炉与回转窑“合并建模—分开控制”的方法,利用前馈神经网络对旋风系统和回转窑系统中的一些重要参量进行建模,设计出双模糊自动控制器,以所建模型为依据,分别对分解炉温度和回转窑3个重要点温度进行控制.实验仿真和现场运行表明,控制器具有响应速度快及控制精度高等优点,受控温度点在短时间内趋于稳定,喂煤量较手操少.%In order to stabilize cement rotary kiln temperature and to reduce its energy consumption, the firing conditions were analyzed and " merger modeling and separate control" method for calciner and kiln was proposed , in which, having feed-forward neural network used to model important parameters of cyclone and rotary kiln system so as to design a dual fuzzy auto-controller for the calciner temperature and the temperature of three important parts in rotary kiln. The simulation result and field operation jointly prove controller' s advantages such as fast response and high precision, and the controlled temperature can tend to become stable in a short time and the coal consumption becomes less than that in manual operation.

  5. Using burnability index to control the burning temperature of rotary kiln%用生料易烧性指数控制回转窑煅烧温度

    Institute of Scientific and Technical Information of China (English)

    袁慧芳; 刘福东; 刘志刚; 杨克锐; 魏庆敏

    2001-01-01

    研究了带余热发电回转窑窑灰对熟料煅烧的影响,结果表明,窑灰的掺入对生料的易烧性和回转窑的煅烧有很大的影响,其中存在一个最佳掺入量。应该严格控制窑灰的加入量,才能保证窑的优质高产。生料的煅烧温度与其易烧性有直接的关系,在设备条件一定的情况下,可以用易烧性来控制窑的煅烧温度。%Influences of rotary kiln dust on clinker burning are investigated in this paper,which is a sub-project of Tangshan mechatronics project-cement synthetical intelligent automatic system.The results show that adding of rotary kiln dust affects both burnabiliy of raw mix and burning of rotary kiln strongly and a best adding amount exists.Adding amount of kiln dust must be controlled strictly to keep the kiln operating well.The burning temperature of raw mix has direct relations with its burnatiliy.Under the same device conditions,using burnability index can control burning temperature of the kiln.

  6. Steel foundry electric arc furnace dust management: stabilization by using lime and Portland cement.

    Science.gov (United States)

    Salihoglu, Guray; Pinarli, Vedat

    2008-05-30

    The purpose of this study was to determine an appropriate treatment for steel foundry electric arc furnace dust (EAFD) prior to permanent disposal. Lime and Portland cement (PC)-based stabilization was applied to treat the EAFD that contains lead and zinc above the landfilling limits, and is listed by USEPA as hazardous waste designation K061 and by EU as 10 02 07. Three types of paste samples were prepared with EAFD content varying between 0 and 90%. The first type contained the EAFD and Portland cement, the second contained the EAFD, Portland cement, and lime, and the third contained the EAFD and lime. All the samples were subjected to toxicity characteristics leaching procedure (TCLP) after an air-curing period of 28 days. pH changes were monitored and acid neutralization capacity of the samples were examined. Treatment effectiveness was evaluated in terms of reducing the heavy metal leachability to the levels below the USEPA landfilling criteria. An optimum composition for the EAFD stabilization was formulated as 30% EAFD +35% lime +35% Portland cement to achieve the landfilling criteria. The pH interval, where the solubility of the heavy metals in the EAFD was minimized, was found to be between 8.2 and 9.4.

  7. Development of MgO-CaO-ZrO2 Refractories in Cement Rotary Kiln%水泥窑用镁钙锆质耐火材料的发展

    Institute of Scientific and Technical Information of China (English)

    田晓利; 薛崇勃; 薛群虎; 闫振华

    2011-01-01

    The development process of cement rotary kiln refractories in cement rotary kiln and the research status of MgO-CaO-ZrO2 refractories in home and abroad were introduced. The MgO-CaO-ZrO2 composite material had advantages of magnesia materials, and its mineral composition contained a certain amount calcium silicate phase. Thus, it had a good thermal shock resistance, a high softening temperature under load, an excellent erosion resistance and suitable mechanical properties, which had important significance and high practical value.%介绍了水泥回转窑用耐火材料的发展历程以及国内外镁钙锆质耐火材料的研究现状,指出MgO-CaO-ZrO2复相材料既具有镁质材料的优点,矿物相组成中又包含一定数量的钙硅酸盐相,从而具有良好的抗热震性、较高的荷重软化温度及优异的抗硅酸盐水泥熟料的侵蚀性能、适宜的力学强度等,具有较高的实用价值.

  8. 室内TDR试验监测石灰矿渣加固粘性土的物理化学反应过程%Laboratory TDR monitoring of physico-chemical process in lime kiln dust stabilized clayey soils

    Institute of Scientific and Technical Information of China (English)

    陈仁明; DAITA; R; K; DRNEVICH; V; P; KIM; D; H

    2006-01-01

    石灰矿渣和水泥矿渣常用于加固道路基层的粘性土.目前现场一般采用未加固土的最大干密度和最优含水率来评价加固土的压实施工质量.但是粘性土掺加了石灰后,发生了复杂的物理化学反应,使得其压实特性与未加固土有很大的不同.采用时域反射计监测石灰加固土内的物理化学反应过程.试验时将不同石灰矿渣掺和量和含水率的Orchard粘土通过标准击实试验夯实于击实筒中,用TDR监测其中的物理化学反应,针式贯入仪监测强度的增长.试验发现,电导率和介电常数的变化反应了土中的离子交换和硬化反应的过程.初始电导率(1 d之内)的减小揭示了石灰矿渣的掺和量的大小,而长期电导率的减小揭示了强度的增长.试验表明,时域反射计技术可用于评价石灰加固土的施工质量.%By-product materials like lime kiln dust (LKD) and cement kiln dust (CKD) begin to be used in the highways and airfield subgrades for improving natural soils to make them suitable construction materials. Most often, dry density and water content are measured in the field for the quality control purposes. Due to the complex physico-chemical reactions in the mixture,the maximum dry density and the optimum water content of the stabilized soils are always quite different from those of natural soil, which make it difficult to evaluate the quality of the stabilized soil. The physico-chemical process in LKD stabilized soil resulted in the change of the electromagnetic properties, which could be monitored by robust, automated, time domain reflectrometry (TDR) technology. LKD stabilized orchard clay with different dosages of LKD and water content were compacted in standard molds. The electrical conductivity and apparent dielectric constant were monitored by TDR to investigate the physico-chemical processes. Needle penetrometer tests were also done on replicate samples at different curing time. It was found that

  9. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  10. Properties of steel foundry electric arc furnace dust solidified/stabilized with Portland cement.

    Science.gov (United States)

    Salihoglu, Guray; Pinarli, Vedat; Salihoglu, Nezih Kamil; Karaca, Gizem

    2007-10-01

    Electric arc furnace dust from steel production is generated in considerable amounts worldwide and needs to be treated as hazardous waste. The aim of this study was to investigate the properties of electric arc furnace dust solidified/stabilized by using Portland cement. Mortar and paste samples were prepared with varying waste-to-binder ratios between 0% and 90%. A comprehensive experimental program was designed including XRF characterization, setting time, unconfined compressive strength, and toxicity characteristics leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), and acid neutralization capacity (ANC) tests. The results were evaluated in order to determine if the solidified /stabilized product can be disposed of at a landfill site with domestic waste or at a segregated landfill. The effect of using sand on S/S performance was also investigated. The results indicated that the solidification /stabilization process using PC helps the heavy metals to be bound in the cement matrix, but the TCLP leaching results exceeded the EPA landfilling limits. The SPLP leaching results conformed to the limits implying that the waste or S/S products can be disposed of at a segregated landfill; however the low ANC of the S/S products reveals that there may be leaching in the long-term. The sand used in the mortar samples adversely affected the S/S performance, causing higher heavy metal leaching levels, and lower pH levels in the leachate after the TCLP extraction than those measured in the leachate of the paste samples.

  11. Celadon of Yue Kiln

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    正Celadon of Yue Kiln comes from the famous ancient Chinese Yue kiln in Southern China. The earliest porcelain was successfully made in this very kiln in the Eastern Han Dynasty, so it is also honored as the "mother porcelain". The kiln stopped producing at the end of the Northern Song Dynasty and the early Southern

  12. 新型干法水泥回转窑设备托轮轴承密封系统的改造%Transformation of Dry Cement Kiln Equipment Supporting Roller Bearing Seal System

    Institute of Scientific and Technical Information of China (English)

    陈风; 曾军林; 古惠芬; 钟日先; 潘春伟

    2014-01-01

    According to the working characteristics of the cement kiln roller sealing system,a new sealing solution,the two-way K-type oil seals with hose clamps was presented. The selection of K-type oil seal materials and the mold structure of the K-type oil seal production were investigated. The optimal interference values of the K-type oil seals were obtained by using ANSYS finite element analysis software. The designed two-way K-type oil seal with hose clamps has good following performance and high sealing reliability,which can realize the good sealing of the kiln supporting roller.%根据水泥回转窑托轮密封系统的工作特点,提出一种新的密封方案---带喉箍的双向K型油封。探讨双向K型油封材料的选取和密封制作模具的结构,借助有限元ANSYS工具分析得到双向K型油封的最优过盈量。带喉箍的双向K型油封的跟随性好,密封可靠性高,能保证旋窑托轮良好的密封。

  13. 水泥回转窑热工测量准确性的影响因素分析%Factors affecting thermal measurement accuracy of cement rotary kiln

    Institute of Scientific and Technical Information of China (English)

    袁秀霞

    2014-01-01

    Thermal measurement of cement rotary kiln is a complex process, there are many factors affecting the accuracy of measure-ment results. Based on many years of rotary kiln thermal measuring experience, for four aspects of test condition selection, scheme;in-strument management and data processing, main factors affecting thermal measurement accuracy were summarized as well as the meth-od of reducing testing data deviation.%水泥回转窑的热工测量是个复杂的过程,测量结果准确性的影响因素较多。根据多年水泥回转窑热工测量经验,从测试条件的选取、测试方案的制定、测试仪器设备的管理和测试数据的处理四个方面,分别总结了影响热工测量数据准确性的主要因素以及减少测试数据出现偏差的方法。

  14. Model of Cement Rotary Kiln Based on Elman Neural Network and Design of DHP Controller%基于Elman网的水泥回转窑模型及其DHP控制器设计

    Institute of Scientific and Technical Information of China (English)

    黄清宝; 林小峰; 宋绍剑; 佘乾仲; 杨宝生

    2011-01-01

    水泥回转窑熟料煅烧过程是一个涉及传质、传热和物理化学反应的复杂的多变量、多扰动、非线性过程.为了稳定回转窑温度以提高水泥熟料烧成质量,降低能耗,需要探索新型优化控制方法.近似动态规划(ADP)综合神经网络、强化学习和动态规划等方法和技术,是一种新型优化方法.其中的双启发式动态规划(DHP)算法由于其评价网络的输出是代价函数关于状态量的偏导数,它具有动态性好、收敛速度快、控制精度高等优点.在分析水泥回转窑工艺的基础上,采用Elman神经回络建立回转窑系统的模型,并利用近似动态规划中的双重启发式动态规划算法设计回转窑温度优化控制器.仿真结果表明,在经历控制初期的波动后,回转窑烧成带温度逐渐趋于稳定,实现了对水泥回转窑的仿真控制.%Calcination process of cement clinker is a complex multi-variable large-disturbances and nonlinear system which is full of mass transfer, heat transfer, physical and chemical reactions. In order to reduce energy consumption and ensure the quality of cement clinker burning, it's necessary to explore new aptimal control methods to stabilize the temperature of rotary kiln. Approximate Dynamic Programming (ADP) integrated neural networks, reinforcement learning and dynamic programming techniques, is a new algorithm for optimal control. The dual heuristic dynamic programming (DHP) is an algorithm of ADP, whose output is a partial derivatrve of cost function with respect to state. It has many advantages such as good dynamics, fast convergence rate, high controlled resolution and so on. Based on the detailed analysis of rotary kiln technology, the model was established by Elman neural network, and the optimization controller was designed with the dual heuristic dynamic programming. The resuks show that, after the fluctuations in the early control period, the temperature of cement rotary kiln tends to

  15. Numerical Evaluation of Brick Lining Status in Rotary Kilns

    OpenAIRE

    2015-01-01

    Rotary kilns are important in a variety of different manufacturing areas for e.g. calcination and sintering of materials. In fact, two of the most produced materials in the world, cement and iron, are likely to start their journey in a rotary kiln.A rotary kiln is a large cylinder-formed furnace which rotates about its axis and where certain chemical and physical reactions take place by the influence of heat. The slope and the rotation make the material inside to move through the kiln from fe...

  16. Germination of Medicago sativa is inhibited by soluble compounds in cement dust.

    Science.gov (United States)

    Lafragüeta, Cristina; García-Criado, Balbino; Arranz, Angel; Vázquez-de-Aldana, Beatriz R

    2014-01-01

    Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6% (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

  17. Counteracting ring formation in rotary kilns

    NARCIS (Netherlands)

    Pisaroni, M.; Sadi, R.; Lahaye, D.

    Avoiding the formation of rings in rotary kilns is an issue of primary concern to the cement production industry. We developed a numerical combustion model that revealed that in our case study rings are typically formed in zones of maximal radiative heat transfer. This local overheating causes the o

  18. Numerical Modeling of Rotary Kiln Productivity Increase

    NARCIS (Netherlands)

    Romero-Valle, M.A.; Pisaroni, M.; Van Puyvelde, D.; Lahaye, D.J.P.; Sadi, R.

    2013-01-01

    Rotary kilns are used in many industrial processes ranging from cement manufacturing to waste incineration. The operating conditions vary widely depending on the process. While there are many models available within the literature and industry, the wide range of operating conditions justifies furthe

  19. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  20. Equilibrium Analysis of Lead in Hazardous Waste During Co-Processing with Cement Kiln%危险废物水泥窑共处置过程Pb的热力学平衡

    Institute of Scientific and Technical Information of China (English)

    王雷; 金宜英; 李润东; 聂永丰

    2011-01-01

    An equilibrium analysis was performed to determine the migration characteristics of lead under the conditions of sintering in cement kiln and municipal solid waste (MSW) incineration. Using the thermodynamic equilibrium software CHEMK1N, the Gibbs free energy of the reaction system was minimized according to chemical potentials combined with atom population constraints. The results indicate that both chloride and SiO2 have great effect on the thermodynamic behavior of lead. Chlorides promote the evaporation of lead, while SiO2 stabilizes lead into silicate. When the incineration temperature in incinerator is higher than 900 K, chlorides mainly exist as HC1. When the sintering temperature is lower than 1 450 K, the ratio of HC1 to chloride is lower than 50%, and the highest ratio of HC1 to total chloride occurs at about 1800 K which is about 80%. Because the main component of cement raw materials is CaCO3, which generates a large amount of CaO after decomposition, an alkaline atmosphere is generated and the generation of HC1 is inhibited. The stabilized rate of lead is 45% in the sintering process in cement kiln, which is much higher than that in the incineration process in incinerator which is only 11%.%采用热力学平衡分析的方法对比研究了水泥窑煅烧条件下重金属Pb的迁移特性,并与焚烧炉焚烧条件下Pb的迁移特性进行了对比.采用CHEMKIN计算软件根据系统吉布斯白南能最小的原理进行计算.结果表明,Cl和SiO2都对重金属Pb的热力学行为有重要影响,Cl促进Pb的挥发,而SiO2有利于Pb的固定.在焚烧炉内,在温度高于900 K的条件下氯几乎全部以HCl的形式存在.在水泥窑中,温度低于1 450 K,HCl占氯的比例低于50%,HCl在约1 800K时所占的比例最大,约为80%.南于水泥生料的主要成分为CaCO3,煅烧后分解产生大量的CaO,使水泥窑内呈现碱性气氛,抑制了HCl气体的生成.水泥窑煅烧过程Pb的固定率为45

  1. 替代燃料对水泥窑用方镁石-复合尖晶石材料的侵蚀%Corrosion of alternative fuels to periclase-compound spinel bricks for cement rotary kilns

    Institute of Scientific and Technical Information of China (English)

    陈树江; 刘耀闻; 李国华; 张国栋; 郝明选; 袁林

    2015-01-01

    This paper aims at researching the produced atmosphere corrosion during the calcination of ce-ment clinker using combustible wastes as substitute fuels to periclase-compound spinel bricks for burning zone of cement kilns.Firstly,chemical reactions between V2 O5 and high purity magnesia or magnesium alu-minate spinel at 1 500 ℃ were researched.Secondly,periclase-compound spinel crucible specimens were prepared at 1 600 ℃ using high purity magnesia,ferruginous magnesia,and hercynite as raw materials;the corrosion medium was prepared using 50% cement clinker,25% rubber tyre and 25% petroleum coke;the static crucible corrosion tests were carried out at 1 450 ℃ for 3 h.The microstructure and phase composition of the corroded specimens were analyzed by SEMand XRD,respectively.It is found that (1)V2 O5 reacts with MgO from spinel forming corundum and magnesium vanadate accompanied by a large volume expansion, deteriorating the spinel structure,thus damaging the brick structure,so when the substitute fuels are used for cement kilns,magnesium aluminate spinel is not a suitable raw material for periclase-compound spinel bricks;(2)the produced acid gases such as SO3 and V2 O5 during the combustion of alternative fuels pene-trate into the bricks along pores and crystal interfaces,gather in pores and crystal interfaces,react with CaO and MgO from periclase-compound spinel bricks forming Ca3 (VO4 )2 ,Mg3 (VO4 )2 ,CaSO4 and MgSO4 ac-companied by volume effect,which is disadvantage to the brick stability;additionally,the acid gases react with C2 S forming low melting phases and CaSO4 ,which goes against the stability of kiln coating.%为了解采用可燃性废弃物作为替代燃料煅烧水泥熟料时产生的气氛对水泥窑烧成带用方镁石-复合尖晶石砖的侵蚀情况,首先进行了化学试剂 V2 O5分别与高纯镁砂和镁铝尖晶石砂在1500℃下的反应试验;然后以高纯镁砂、高铁镁砂、铁铝尖晶石砂为原料,于1600℃

  2. Present Situation and Perspective of Chinese Cement Industry

    Institute of Scientific and Technical Information of China (English)

    Gao Changming

    2003-01-01

    @@ Totally, there are 12 types of cement kiln pro-duction lines in China and running with a quite differenttechnical- economical levels. The cement productionof different types product lines in 1997 ~ 2002 is shownin Table 1.

  3. Strength of Ternary Blended Cement Sandcrete Containing Afikpo Rice Husk Ash and Saw Dust Ash

    Directory of Open Access Journals (Sweden)

    L. O. Ettu

    2013-01-01

    Full Text Available This work investigated the compressive strength of ternary blended cement sandcrete containing Afikpo rice husk ash (RHA and sawdust ash (SDA. 105 sandcrete cubes of 150mm x 150mm x 150mm were produced with OPC-RHA binary blended cement, 105 with OPC-SDA binary blended cement, and 105 with OPC-RHA-SDA ternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%. Three cubes for each percentage replacement of OPC with pozzolan and the control were tested for saturated surface dry bulk density and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. The 90-day strengths obtained from ternary blending of OPC with equal proportions of RHA and SDA were 11.80N/mm2for 5% replacement, 11.20N/mm2for 10% replacement, 10.60N/mm2for 15% replacement, 10.00N/mm2for 20% replacement, and 9.10N/mm2for 25% replacement, while that of the control was 10.90N/mm2. This suggests that very high sandcrete strength values could be obtained with OPCRHA-SDA ternary blended cement with richer mixes, high quality control, and longer days of hydration. Thus, OPC-RHA-SDA ternary blended cement sandcrete could be used for various civil engineering and building works, especially where early strength is not a major requirement.

  4. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    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......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......, 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...

  5. A coincineração de resíduos em fornos de cimento: riscos para a saúde e o meio ambiente Co-incineration in cement kilns: health and environmental risks

    Directory of Open Access Journals (Sweden)

    Bruno Milanez

    2009-12-01

    Full Text Available O objetivo do artigo é discutir a forma como a coincineração de resíduos em fábricas de cimento vem crescendo no Brasil, bem como seus impactos sobre a saúde humana e o meio ambiente. Informações gerais sobre mercado e efeitos sobre a saúde foram obtidas através de revisão bibliográfica e alguns estudos de caso, escolhidos a partir de debate com integrantes da Rede Brasileira de Justiça Ambiental, foram construídos para ilustrar a situação no Brasil. Os estudos encontrados mostraram que, independente do nível de desenvolvimento tecnológico dos países, a saúde dos trabalhadores e das pessoas que moram próximas às fábricas de cimento vem sendo prejudicada pela poluição emitida pelas empresas de cimento, em especial por aquelas que praticam a coincineração. Além disso, no contexto brasileiro, a vulnerabilidade das instituições e populações afetadas tende a agravar este problema. Como conclusão, defende-se o aumento da capacidade institucional dos órgãos brasileiros responsáveis pelo monitoramento das atividades industriais, bem como uma rediscussão mais aprofundada dos aspectos políticos e éticos ligados ao transporte e comércio de resíduos industriais.In this article we discuss the development of hazardous waste co-incineration in cement kilns in Brazil as well as its impacts on health and the environment. Information was gathered through an extensive review on social and environmental impacts of co-incineration, and case studies, chosen after discussion with social movement representatives concerned with the co-incineration issue and related to the Brazilian Network on Environmental Justice, are described to illustrate the reality of co-incineration in Brazil. Studies showed that workers and community health suffers negative impacts from such practices in high-, middle- and low-income countries. In the Brazilian context, the institutional and social vulnerability intensifies these problems. To conclude, we

  6. 40 CFR 63.1205 - What are the standards for hazardous waste burning lightweight aggregate kilns that are effective...

    Science.gov (United States)

    2010-07-01

    ... Emissions Standards and Operating Limits for Incinerators, Cement Kilns, and Lightweight Aggregate Kilns... must not discharge or cause combustion gases to be emitted into the atmosphere that contain: (1) For...) Rapid quench of the combustion gas temperature at the exit of the (last) combustion chamber (or exit...

  7. Thoracic dust exposure is associated with lung function decline in cement production workers.

    Science.gov (United States)

    Nordby, Karl-Christian; Notø, Hilde; Eduard, Wijnand; Skogstad, Marit; Fell, Anne Kristin; Thomassen, Yngvar; Skare, Øivind; Bergamaschi, Antonio; Pietroiusti, Antonio; Abderhalden, Rolf; Kongerud, Johny; Kjuus, Helge

    2016-08-01

    We hypothesised that exposure to workplace aerosols may lead to lung function impairment among cement production workers.Our study included 4966 workers in 24 cement production plants. Based on 6111 thoracic aerosol samples and information from questionnaires we estimated arithmetic mean exposure levels by plant and job type. Dynamic lung volumes were assessed by repeated spirometry testing during a mean follow-up time of 3.5 years (range 0.7-4.6 years). The outcomes considered were yearly change of dynamic lung volumes divided by the standing height squared or percentage of predicted values. Statistical modelling was performed using mixed model regression. Individual exposure was classified into quintile levels limited at 0.09, 0.89, 1.56, 2.25, 3.36, and 14.6 mg·m(-3), using the lowest quintile as the reference. Employees that worked in administration were included as a second comparison group.Exposure was associated with a reduction in forced expiratory volume in 1 s (FEV1), forced expiratory volume in 6 s and forced vital capacity. For FEV1 % predicted a yearly excess decline of 0.84 percentage points was found in the highest exposure quintile compared with the lowest.Exposure at the higher levels found in this study may lead to a decline in dynamic lung volumes. Exposure reduction is therefore warranted.

  8. Cordierite Self Flow Castables for Kiln Furniture

    Institute of Scientific and Technical Information of China (English)

    CHENZhiqiang; B.Myhre; 等

    1999-01-01

    In addition to 0.5-4 mm cordierite,0-0.5 mm cordierite can be used to substitute counterpart alumina in both ultralow and low cement cordierite self slowing castables,total cordierite can cordierite self flowing castables,total cordierite can reach 49 wt%, approximately 60 vol% ,the self flowing value, apparent porosity,bulk density,permanent linear change and modulus of rupture are measured.When ultralow cement samples fired at and below 1300℃,codierite can incerease the hot strength of castables and promote mullite formation,When samples fired at 1350℃ ,HMOR is: A28>A35>A42>A49,but all o them are strong enough,When low cement samples re fired nd tested below 1300℃,the hot strength does not change very much with cordierite content generally,Cordierite containing castables for kiln furnitrure need to be fired at least 6 h at 1300℃-1350℃ for ultralow cement astables and at 1250℃-1300℃ for low cement castables,in order to make mullite formed.

  9. Socio-environmental Impacts Associated with Burning Alternative Fuels in Clinker Kilns

    Directory of Open Access Journals (Sweden)

    F. B. Mainier

    2013-08-01

    Full Text Available The pollutants found in emissions from cement plants depend on the processes used and the operation of the clinker kilns. Another crucial aspect concerns the characteristics of raw materials and fuels. The intensive use of fuels in rotary kilns of cement plants and the increasing fuel diversification, including fuels derived from coal and oil, from a multitude of industrial waste and from biomass, charcoal and agricultural waste (sugarcane bagasse, rice husk, is increasing the possibilities of combinations or mixtures of different fuels, known as blends. Thus, there are socio-environmental impacts associated with the burning of alternative fuels in clinker kilns. In view of the growing trend of entrepreneurs who want to target the waste produced in their unit and of the owners of the cement plants who want to reduce their production costs by burning a waste with lower cost than conventional fuels, it is necessary to warn that a minimum level of environmental care should be followed regarding these decisions. It is necessary to monitor the points of emission from cement kilns and in the wider area influenced by the plant, in order to improve environmental quality. Laboratory studies of burning vulcanised rubber contaminated with arsenic simulate the burning of used tyres in cement clinker kilns producing SO2 and As2O3.

  10. Mixing large and small particles in a pilot scale rotary kiln

    DEFF Research Database (Denmark)

    Nielsen, Anders Rooma; Aniol, Rasmus Wochnik; Larsen, Morten Boberg;

    2011-01-01

    The mixing of solid alternative fuel particles in cement raw materials was studied experimentally by visual observation in a pilot scale rotary kiln. Fuel particles were placed on top of the raw material bed prior to the experiment. The percentage of particles visible above the bed as a function...... of time was evaluated with the bed predominantly in the rolling bed mode. Experiments were conducted to investigate the effects of fuel particle size and shape, fuel particle density, rotary kiln fill degree and rotational speed. Large fuel particles and low-density fuel particles appeared more on top.......Results can be up-scaled to industrial conditions in cement rotary kilns and show that even relatively large fuel particles will predominantly be covered by raw material after less than 30s in the rotary kiln. This affects the heating and combustion mechanisms for the fuel particles....

  11. EVALUASI EFISIENSI PANAS DAN EMISI GAS RUMAH KACA PADA ROTARY KILN PABRIK SEMEN

    Directory of Open Access Journals (Sweden)

    Farisa Ridha Mutiara

    2012-08-01

    Full Text Available Kiln is an equipment which has vital existence in the manufacture of cement. Kiln firing requires a hightemperature to produce a clinker. Higher combustion temperature allows heat transfer occurs on the surfacecoating on the walls of the kiln that is not evenly distributed, so most of the heat is absorbed. As a consequence,it requires large amounts of fuel. Heat efficiency in the kiln is important to know. Production of clinker in thekiln which occurs at high temperatures, will also release a variety of gases, such as CO2. Carbon dioxide isincluded as one of the greenhouse gas, this gas will negatively impact the earth's ozone. Therefore, need to knowthe range of greenhouse gas that is formed, in order to determine the appropriate mitigation and prevention.Evaluation result of heat efficiency in the kiln is 43,17% by generating greenhouse gas emissions amounted to6,173 tonnes CO2 equivalent / tonne of coal.

  12. PO43 Removal by and Permeability of Industrial Byproducts and Minerals: Granulated Blast Furnace Slag, Cement Kiln Dust, Coconut Shell Activated Carbon, Silica Sand and Zeolite

    Science.gov (United States)

    Excess aqueous concentration of phosphate degrades the overall water quality of the receiving surface waters in a cumulatively damaging process referred to as eutrophication. Adsorption of excess phosphate has proven to be the most effective, and economical methods of phosphate removal from such wat...

  13. Analysis on chemical valence of chromium in residual MgO-Cr2O3 bricks for cement rotary kilns and RH fur-naces%水泥回转窑和RH炉用镁铬残砖中铬价态分析

    Institute of Scientific and Technical Information of China (English)

    姚晨臣; 王亚娟; 杨晓; 宋秀娟; 马娟; 李爽; 叶国田

    2014-01-01

    为了弄清含铬耐火材料是否在使用过程中都会形成六价铬化合物,采用XRD、XPS 和ICP等手段分析了水泥回转窑烧成带用镁铬残砖及RH炉(浸渍管)用镁铬残砖中Cr6+的存在情况。结果表明:水泥回转窑烧成带用镁铬残砖中有六价铬化合物存在,并且含量较高;RH炉(浸渍管)用镁铬残砖中没有发现六价铬化合物。这表明,并非在所有应用环境中含铬耐火材料都会生成六价铬化合物。%In order to investigate whether hexavalent chromium is formed in all Cr2O3-containing refractories during service,XRD,XPS and ICP were used to determine the chemical valence of chromium in residual MgO-Cr2O3 bricks for firing zone of cement rotary kilns and RH furnaces (snorkel).The results show that Cr6+is detected in the residual MgO-Cr2O3 bricks for cement rotary kilns,but not in the bricks for RH fur-naces,indicating that hexavalent chromium does not form in all applications of Cr2O3-containing refractories.

  14. Effect of Exposure to Portland Cement Dust on the Periodontal Status and on the Outcome of Non-Surgical Periodontal Therapy

    Science.gov (United States)

    Abdelhamid, Alaa

    2016-01-01

    Background Cement dust contains heavy metals like nickel, cobalt, lead and chromium, pollutants hazardous to the biotic environment, with adverse impact for vegetation, human and animal health and ecosystems. Objective To investigate if long term exposure to cement dust can affect the periodontal health and affect the outcome of non-surgical periodontal therapy. Methods A total of sixty subjects were included in this study. Forty patients with chronic periodontitis were grouped into; Group I comprised of 20 patients with chronic periodontitis working in the Portland Cement Company and Group II comprised of 20 patients with chronic periodontitis who does not work in cement factories nor live near any of them. Twenty healthy subjects were included in this study as healthy control group (Group III). Clinical parameters including gingival index (GI), plaque index (PI), pocket depth (PD) and clinical attachment loss (CLA) were scored for all patients before and after periodontal therapy. All patients received non-surgical periodontal therapy together with strict oral hygiene program for one month. Gingival crevicular fluid (GCF) samples were collected from both groups at baseline and one month after periodontal therapy. Real time PCR (RT-PCR) was used to analyze the GCF samples for detection and assessment of the levels of IL-1β and TNFα. Results The two studied groups responded well to non-surgical periodontal treatment and there was no significant difference between GI and GII (P>0.05). The levels of TNFα was higher in GI than in GII before and after periodontal therapy (P0.05), but represented with a highly significant difference between G1 and GII after periodontal therapy (Psurgical periodontal treatment but it affects the levels of the pro-inflammatory mediators leading to more periodontal tissue destruction. PMID:27610057

  15. Kilns and Firing Structures

    OpenAIRE

    Nicholson, Paul

    2010-01-01

    The purpose of firing pottery is to change clay, a plastic material, into ceramic, which is aplastic. Examined here are structures designed to fire pottery or faience or to make glass (although the latter might be better described as furnaces). Firing can take place in an open, bonfire-like environment, which can also be enclosed as a firing structure. Beyond this is the development of the true kiln of which there are two main types: updraft and downdraft. The first of these is by far the mos...

  16. The Materials and Energy Potential Method for the quantitative distincion between Valorization and Elimination in the Cement Industry

    NARCIS (Netherlands)

    Zeevalkink, J.A.; Alkemade, M.M.C.

    1996-01-01

    This report proposes a quantitative method to distinguish between valorization and elimination of waste in a cement kiln. Examples are calculated to illustrate the consequences of the developed approach. Valorization is defined as the processing of a waste in a cement kiln to substi-tute raw materia

  17. Biomonitoring Study of Heavy Metals in Blood from a Cement Factory Based Community

    Directory of Open Access Journals (Sweden)

    Bank M.S.

    2014-07-01

    Full Text Available Little is known about the effects of cement factory pollution, emissions, and kiln dust on contaminant exposure in human populations, including school environments, in close proximity to these point sources. In Ravena, New York, USA and vicinity, environmental pollution from a local cement plant is considered significant and substantial according to the United States Environmental Protection Agency’s Toxic Release Inventory, published in 2006, 2007, and 2010. We hypothesized that cement factory based communities, such as the one in Ravena, NY, may be differentially exposed to heavy metals, including mercury, via dust, soil, and air in addition to any contributions from fish consumption, dental amalgams, smoking habits, and occupational exposures, etc. Here we report measurements of several heavy metals in blood (Pb, Cd, As, Hg, Se and Al and, for comparative purposes, total mercury in hair from a local (six-mile radius population of Caucasian adults and children. We also report and synthesize local atmospheric emissions inventory information and new indoor air data (NYSERDA, 2011 from the local school which is situated directly across the street (within 750 feet from the cement factory and quarry. In addition, to our human and environmental heavy metal results we also discuss scientific outreach coordination, and public health action opportunities that will likely have wide applicability for other community and environmental health studies confronting similar pollution issues.

  18. Comparison of Temperature Field Distribution between Cement Preclinkering Technology and Cement Precalcining Technology

    Institute of Scientific and Technical Information of China (English)

    XU Xun; WANG Lan

    2016-01-01

    Through the comparison of calcination conditions between cement preclinkering technology and cement precalcining technology, we studied the characteristics of temperature ifeld distribution of cement preclinkering technology systems including cyclone preheater, preclinkering furnace, and rotary kiln. We used numerical simulation method to obtain data of temperature ifeld distribution.Some results are found by system study. The ratio of tail coal of cement preclinkering technology is about 70%, and raw meal temperature can reach 1070℃. ShorterL/D kiln type of preclinkering technology can obtain more stable calcining zone temperature. The highest solid temperature of cement preclinkering technology is higher than 80℃, and high temperature region (>1450℃) length is 2 times, which is beneifcial for calcining clinker and higher clinker quality. So cement preclinkering technology can obtain more performance temperature ifled, which improves both the solid-phase reaction and liquid-phase reaction.

  19. 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...... is the most energy demanding process, takes place at lower temperature in the calciner. When dealing with NOx from solid fuel combustion it is important to consider reactions of volatile contents and char separately.Chapter 4 presents an overview of NOx from cement production. Thermal NOx dominates from......, 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...

  20. Cement Formation:A Success Story in a Black Box: High Temperature Phase Formation of Portland Cement Clinker

    OpenAIRE

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledgeabout the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in ...

  1. Cement Manufacturing Plant Guidelines: An Approach to Reconciling the Financing of Cement with Climate Change Objectives

    OpenAIRE

    2010-01-01

    Cement manufacturing is an energy-intensive process, requiring high fuel consumption to operate cement kilns, which in turn generates carbon dioxide (CO2). These Guidelines aim to provide clear and quantitative Minimum Climate Change Performance Criteria necessary for IDB to support projects, as well as guidance on assessing and reducing the greenhouse gas (GHG) emissions of projects. The purpose of the Cement Manufacturing Plant guidelines is to set forth an approach for the financing of new...

  2. Kiln emissions and potters' exposures.

    Science.gov (United States)

    Hirtle, B; Teschke, K; van Netten, C; Brauer, M

    1998-10-01

    Some ten thousand British Columbia potters work in small private studios, cooperative facilities, educational institutions, or recreation centers. There has been considerable concern that this diffuse, largely unregulated activity may involve exposures to unacceptable levels of kiln emissions. Pottery kiln emissions were measured at 50 sites--10 from each of 5 categories: professional studios, recreation centers, elementary schools, secondary schools, and colleges. Area monitoring was done 76 cm from firing kilns and 1.6 m above the floor to assess breathing zone concentrations of nitrogen dioxide, carbon monoxide, sulfur dioxide, fluorides, aldehydes, aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, gold, iron, lead, lithium, magnesium, manganese, mercury, nickel, selenium, silver, vanadium, and zinc. Personal exposures to the same metals were measured at 24 sites. Almost all measured values were well below permissible concentrations for British Columbia work sites and American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs) with the following two exceptions. A single firing duration (495 minute) acrolein measurement adjacent to an electric kiln (0.109 ppm) exceeded these guidelines. One 15-minute sulfur dioxide measurement collected adjacent to a gas kiln (5.7 ppm) exceeded the ACGIH short-term exposure limit. The fact that concentrations in small, ventilated kiln rooms ranked among the highest measured gives rise to concern that unacceptable levels of contamination may exist where small kiln rooms remain unventilated. Custom designed exhaust hoods and industrial heating, ventilating, and air-conditioning systems were the most effective ventilation strategies. Passive diffusion and wall/window fans were least effective.

  3. A review of binders used in cemented paste tailings for underground and surface disposal practices.

    Science.gov (United States)

    Tariq, Amjad; Yanful, Ernest K

    2013-12-15

    Increased public awareness of environmental issues coupled with increasingly stringent environmental regulations pertaining to the disposal of sulphidic mine waste necessitates the mining industry to adopt more competent and efficient approaches to manage acid rock drainage. Cemented paste tailings (CPT) is an innovative form of amalgamated material currently available to the mining industry in developed countries. It is made usually from mill tailings mingled with a small amount of binder (customarily Portland cement) and water. The high cost associated with production and haulage of ordinary Portland cement and its alleged average performance as a sole binder in the long term (due to vulnerability to internal sulphate attack) have prompted users to appraise less expensive and technically efficient substitutes for mine tailings paste formulations. Generally, these binders include but are not limited to sulphate resistant cements, and/or as a partial replacement for Portland cement by artificial pozzolans, natural pozzolans, calcium sulphate substances and sodium silicates. The approach to designing environmentally efficient CPT is to ensure long-term stability and effective control over environmental contaminants through the use of composite binder systems with enhanced engineering properties to cater for inherit deficiencies in the individual constituents. The alkaline pore solution created by high free calcium rich cement kiln dust (CKD) (byproduct of cement manufacturing) is capable of disintegrating the solid glassy network of artificial pozzolans to produce reactive silicate and aluminate species when attacked by (OH(-)) ions. The augmented pozzolanic reactivity of CKD-slag and CKD-fly ash systems may produce resilient CPT. Since cemented paste comprising mine tailings and binders is a relatively new technology, a review of the binding materials used in such formulations and their performance evaluation in mechanical fill behaviour was considered pertinent in

  4. Research of fluidized bed cement clinker sintering system by pilot plant; Ryudosho cement shosei gijutsu no kaihatsu. 7

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, T. [Center for Coal Utilization, Japan, Tokyo (Japan); Sato, N.; Hashimoto, I.; Nakatsuka, M. [The Cement Association of Japan, Tokyo (Japan)

    1996-09-01

    While a cement manufacturing process generally performs sintering by using a rotary kiln, a development work has been carried out as a subsidy operation of the Agency of Natural Resources and Energy on a cement sintering technology using a fluidized bed consisted of two furnaces: a jet flow bed granulating furnace and a fluidized bed sintering furnace. This paper reports the results of tests and researches performed during fiscal 1995. A plant with a scale of 20 ton-a-day production started in 1993 after having gone through bench scale tests. The year 1995 conducted by August its performance evaluation, review of the operation method and the safety criteria, and generalization of the tests. A multi-stage cyclone system has been employed in the preheating equipment for cement material powder. A number of improvements have been realized in the aspects of construction and operation, such as stabilization of dust collecting efficiency by employing a high-efficiency type cyclone, and operation with reduced pressure variation. Based on these results, a construction had been progressed in parallel on a new plant upscaled to 200 ton-a-day production. The new plant was completed in December, 1995. 9 figs., 8 tabs.

  5. Energy Efficiency Improvement Opportunities for the Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn; Worrell, Ernst; Galitsky, Christina; Price, Lynn

    2008-01-31

    This report provides information on the energy savings, costs, and carbon dioxide emissions reductions associated with implementation of a number of technologies and measures applicable to the cement industry. The technologies and measures include both state-of-the-art measures that are currently in use in cement enterprises worldwide as well as advanced measures that are either only in limited use or are near commercialization. This report focuses mainly on retrofit measures using commercially available technologies, but many of these technologies are applicable for new plants as well. Where possible, for each technology or measure, costs and energy savings per tonne of cement produced are estimated and then carbon dioxide emissions reductions are calculated based on the fuels used at the process step to which the technology or measure is applied. The analysis of cement kiln energy-efficiency opportunities is divided into technologies and measures that are applicable to the different stages of production and various kiln types used in China: raw materials (and fuel) preparation; clinker making (applicable to all kilns, rotary kilns only, vertical shaft kilns only); and finish grinding; as well as plant wide measures and product and feedstock changes that will reduce energy consumption for clinker making. Table 1 lists all measures in this report by process to which they apply, including plant wide measures and product or feedstock changes. Tables 2 through 8 provide the following information for each technology: fuel and electricity savings per tonne of cement; annual operating and capital costs per tonne of cement or estimated payback period; and, carbon dioxide emissions reductions for each measure applied to the production of cement. This information was originally collected for a report on the U.S. cement industry (Worrell and Galitsky, 2004) and a report on opportunities for China's cement kilns (Price and Galitsky, in press). The information provided in

  6. Occupational Health Hazards of Women Working in Brick Kiln and Construction Industry

    Directory of Open Access Journals (Sweden)

    V. G Vaidya

    2015-01-01

    Full Text Available Background: In brick kiln and construction industry the exposure to carbon monoxide and silica dust is the most common occupational hazard to the workers in these industries. A study on occupational health hazards of working women in these two unorganized sectors was undertaken by Lokmanya Medical Research Centre. Objectives: To study the effect of work site environment on the health of the women working in brick kiln and construction industry. An attempt was also made to study the seasonal changes in the concentration of carbon monoxide and dust at the worksite. Material and Methods: A cross-sectional study was conducted among the working women (age 18-40 years at brick kilns and construction sites during summer and winter season. They were examined primarily to assess the effect of working environment on health. Gasteck Detector Pump of model 800 and air sampling instrument (SKC Air Check–52 were used to measure concentration of carbon monoxide and dust in the air respectively. Results: There were 66% of women who were in the age group of 18-40 years and most of them (94% were married. At brick kiln sites, average CO exposure was 62.8 ppm and 55.5 ppm and average dust exposure was 3 3 146.1 mg/m and 91.4 mg/m in summer and winter season respectively.At construction sites, average dust exposure was 41.5 ppm and 90.8 ppm in summer and winter. Conclusion: Both exposure to CO and dust were more in summer than in winter in brick kiln industry whereas in construction industry the exposure to dust was more in winter season. A high level of morbidity in the form of headache, bodyache, problems with vision, cough and breathlessness were observed in both industries. It is strongly recommended to take pollution control measures.

  7. The Magnetic Properties of Lichens Exposed Around a Cement Plant in Slovakia

    Science.gov (United States)

    Winkler, Aldo; Paoli, Luca; Guttová, Anna; Loppi, Stefano; Sagnotti, Leonardo

    2015-04-01

    A cement industry is a source of dust pollution, from quarrying and grinding of the raw material to kiln operations. Airborne pollutants related to combustion processes are also emitted, especially during kiln operations and power generation. The use of biomonitors can provide valuable information about the impact of airborne pollutants released during cement production and lichens are suitable bioindicators of air pollution, providing reliable information on the quality of the environment. We investigated the magnetic hysteresis properties and the elemental concentrations of epiphytic lichens from selected sites (a cement mill, two quarries, agricultural areas, and villages) in SW Slovakia; in particular, both transplanted and in situ lichens, bark, soil and rock samples from the sampling sites, as well as pre-transplant samples have been characterized. Evernia prunastri transplants, exposed up to 180 days, showed excellent correlations between the saturation magnetization (Ms) and saturation remanent magnetization (Mrs) values and the Fe concentrations; the analyzed samples were magnetically homogeneous, with marked differences only for the sample from a basalt quarry. Xanthoria parietina autochthonous samples have also a similar magnetic mineralogy; anyway their Ms and Mrs values were two orders of magnitude higher with respect to those from the transplants, implying increased concentration of magnetic particles according to the different lichen species and to the prolonged exposure. Magnetic methods can be valuable for discriminating various natural and anthropogenic sources of dust. In this study, we point out that the magnetic properties may also reflect the influence of the basalt quarry activity, of the soil and of the bedrock. For a proper evaluation of the pollution related to human activities, it is thus essential to verify the nature of the substrate and to select suitable and homogeneous pre/post lichen transplant sites.

  8. 40 CFR 63.1201 - Definitions and acronyms used in this subpart.

    Science.gov (United States)

    2010-07-01

    ..., mill scale, cement kiln dust and flyash, that are fed to a cement or lightweight aggregate kiln. Raw... kiln raw mill means a hazardous waste burning cement kiln design whereby kiln gas is ducted through the raw material mill for portions of time to facilitate drying and heating of the raw...

  9. Biomonitoring with epiphytic lichens as a complementary method for the study of mercury contamination near a cement plant.

    Science.gov (United States)

    Ljubič Mlakar, Tanja; Horvat, Milena; Kotnik, Jože; Jeran, Zvonka; Vuk, Tomaž; Mrak, Tanja; Fajon, Vesna

    2011-10-01

    The study was focused on understanding the mercury contamination caused by a cement plant. Active and passive biomonitoring with epiphytic lichens was combined with other instrumental measurements of mercury emissions, mercury concentrations in raw materials, elemental mercury concentrations in air, quantities of dust deposits, temperatures, precipitation and other measurements from the cement plant's regular monitoring programme. Active biomonitoring with transplanted lichens Pseudevernia furfuracea (L.) Zopf was performed at seven of the most representative sites around the cement plant and one distant reference site for periods of 3, 6 and 12 months. In situ lichens of different species were collected at the beginning of the monitoring period at the same sites. Mercury speciation of the plant exhaust gas showed that the main form of emitted mercury is reactive gaseous mercury Hg²⁺, which is specific for cement plants. Elemental mercury in air was measured in different meteorological conditions using a portable mercury detector. Concentrations in air were relatively low (on average below 10 ng m⁻³). In situ lichens showed Hg concentrations comparable to lichens taken from the background area for transplantation, indicating that the local pollution is not severe. Transplanted lichens showed an increase of mercury, especially at one site near the cement plant. A correlation between precipitation and Hg uptake was not found probably due to a rather uniform rainfall in individual periods. Dust deposits did not influence Hg uptake significantly. Lichens vitality was affected over longer biomonitoring periods, probably due to some elements in dust particles, their alkalinity and the influence of other emissions. Mercury uptake measured in vital transplanted lichens was in a good correlation with the working hours (i.e. emitted Hg quantity) of the kiln. The study showed that selected lichens could be used to detect low to moderate Hg emissions from a cement plant

  10. Secondary fuels and raw materials in the Spanish cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Gordobil, J.C.U.; Guede, Elena [Cementos Lemona s.a. (Spain)

    1997-03-01

    The growing environmental and energy concern are having an impact on the Spanish cement industry. This article describes the impact on waste management, the operation of cement kilns and the possibility for recycling. Current projects and future prospects are described. (UK)

  11. A Pottery Electric Kiln Using Decompression

    Science.gov (United States)

    Naoe, Nobuyuki; Yamada, Hirofumi; Nakayama, Tetsuo; Nakayama, Minoru; Minamide, Akiyuki; Takemata, Kazuya

    This paper presents a novel type electric kiln which fires the pottery using the decompression. The electric kiln is suitable for the environment and the energy saving as the pottery furnace. This paper described the baking principle and the baking characteristic of the novel type electric kiln.

  12. Sulfur Release from Cement Raw Materials during Solid Fuel Combustion

    DEFF Research Database (Denmark)

    Nielsen, Anders Rooma; Larsen, Morten B.; Glarborg, Peter

    2011-01-01

    During combustion of solid fuels in the material inlet end of cement rotary kilns, local reducing conditions can occur and cause decomposition of sulfates from cement raw materials. Decomposition of sulfates is problematic because it increases the gas-phase SO2 concentration, which may cause...... deposit formation in the kiln system. SO2 release from cement raw materials during combustion of solid fuels has been studied experimentally in a high temperature rotary drum. The fuels were tire rubber, pine wood, petcoke, sewage sludge, and polypropylene. The SO2 release from the raw materials...

  13. Application of ESP for gas cleaning in cement industry--with reference to India.

    Science.gov (United States)

    Bapat, J D

    2001-02-16

    Electrostatic precipitators (ESP) are used for gas cleaning in almost every section of cement manufacture. Application of ESP is studied, keeping in view Indian conditions. The characterisation of dust emissions has been done for different units, such as rotary kiln and raw mill, alkali by-pass, clinker cooler, cement and coal mill, in terms of exit gas quantity, temperature, dew point, dust content and particle size. It is seen that all these characteristics have a wide range of variance. The ESP system must effectively deal with these variations. The fundamental analytical expression governing the performance of ESP, i.e. the Deutsch equation, and that for particle migration velocity, were analysed to predict the effect of major operating parameters, namely particle size, temperature and applied voltage. Whereas the migration velocity (and the efficiency) varies directly with the particle size, it is proportional to the square and square root of applied voltage and absolute temperature of the gas, respectively. The increase in efficiency due to temperature is not seen in dc based ESP, perhaps due to more pronounced negative effect on the applied voltage due to the increase in dust resistivity at higher temperatures. The effect of gas and dust characteristics on the collection efficiency of ESP, as seen in the industrial practice, is summarised. Some main process and design improvements effectively dealing with the problem of gas and dust characteristics have been discussed. These are gas conditioning, pulse energization, ESP-fabric filter (FF) combination, improved horizontal flow as well as open top ESP.Generally, gas conditioning entails higher operating and maintenance costs. Pulse energization allows the use of hot gas, besides reducing the dust emission and power consumption. The improved horizontal flow ESP has been successfully used in coal dust cleaning. The open top or vertical flow ESP has a limitation on collection efficiency as it provides for only

  14. Evaluation of cement production using a pressurized fluidized-bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    DeLallo, M.; Eshbach, R.

    1994-01-01

    There are several primary conclusions which can be reached and used to define research required in establishing the feasibility of using PFBC-derived materials as cement feedstock. 1. With appropriate blending almost any material containing the required cement-making materials can be utilized to manufacture cement. However, extensive blending with multiple materials or the use of ash in relatively small quantities would compromise the worth of this concept. 2. The composition of a potential feedstock must be considered not only with respect to the presence of required materials, but just as significantly, with respect to the presence and concentration of known deleterious materials. 3. The processing costs for rendering the feedstock into an acceptable composition and the energy costs associated with both processing and burning must be considered. It should be noted that the cost of energy to produce cement, expressed as a percentage of the price of the product is higher than for any other major industrial product. Energy consumption is, therefore, a major issue. 4. The need for conformance to environmental regulations has a profound effect on the cement industry since waste materials can neither be discharged to the atmosphere or be shipped to a landfill. 5. Fifth, the need for achieving uniformity in the composition of the cement is critical to controlling its quality. Unfortunately, certain materials in very small concentrations have the capability to affect the rate and extent to which the cementitious compound in portland cement are able to form. Particularly critical are variations in the ash, the sulfur content of the coal or the amount and composition of the stack dust returned to the kiln.

  15. Solar lumber kiln. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    The purpose of this project was to establish design parameters for the construction of small scale (1000 board foot capacity) lumber drying kiln which derives its thermal energy from the sun. Results of a six month monitoring period are presented, as well as second generation design considerations and simplified control logic. (LEW)

  16. ROTARY SCREW SYSTEMS IN CEMENT

    OpenAIRE

    2016-01-01

    The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometr...

  17. Devolatilization and Combustion of Tire Rubber and Pine Wood in a Pilot Scale Rotary Kiln

    DEFF Research Database (Denmark)

    Nielsen, Anders R.; Larsen, Morten B.; Glarborg, Peter

    2012-01-01

    of industrial waste. In this study, devolatilization and combustion of large particles of tire rubber and pine wood with equivalent diameters of 10 mm to 26 mm are investigated in a pilot scale rotary kiln able to simulate the process conditions present in the material inlet end of cement rotary kilns....... Investigated temperatures varied from 700 to 1000 °C, and oxygen concentrations varied from 5% v/v O2 to 21% v/v O2. The devolatilization time of tire rubber and pine wood were found to mainly depend on temperature and particle size and were within 40 to 170 s. Rate limiting parameters for char oxidation...... of tire rubber and pine wood were found to be bulk oxygen concentration, mass transfer rate of oxygen, raw material fill degree, raw material characteristics, and temperature. Kiln rotational speed only had a minor effect on the char oxidation when the raw material bed was in a rolling motion. Initial...

  18. Inhaled dust and disease

    Energy Technology Data Exchange (ETDEWEB)

    Holt, P.F.

    1987-01-01

    This book discusses the following: the respiratory system; respirable dust; the fate of inhaled dust; translocation and some general effects of inhaled dust; silicosis; experimental research on silica-related disease; natural fibrous silicates; asbestos dust levels and dust sources; asbestos-related diseases - asbestosis, lung cancer, mesothelioma and other diseases, cancers at sites other than lung and pleura; experimental research relating to asbestos-related diseases; asbestos hazard - mineral types and hazardous occupations, neighbourhood and domestic hazard; silicates other than asbestos-man-made mineral fibres, mineral silicates and cement; metals; coal mine dust, industrial carbon and arsenic; natural and synthetic organic substances; dusts that provoke allergic alveolitis; tobacco smoke.

  19. Assessing the Effect of Cement Dust Emission on the Physicochemical Nature of Soil around Messebo area, Tigray, North Ethopia

    Directory of Open Access Journals (Sweden)

    SAMUEL ESTIFANOS

    2012-12-01

    Full Text Available Twenty six soil samples were collected around the vicinity of Messebo cement factory in Mekelle, Ethiopia from 0-5 and 5-15 cm depths and determined their physicochemical properties and heavy metals contents. The results indicated that the soils are calcareous having sandy loam to loamy sand texture. The top and lower parts of the soil are found to be alkaline with mean pH 8.97 and 8.93; EC 223.06 and 88.22 µS/cm respectively. The cation exchange capacity of the top soil (0-5cm range from 9 to 27 mmolc kg-1, while the exchangeable Ca and Mg range from 6.4 to 16 and 2.2 to 5.0 mmolc kg- 1 respectively. The average Ca concentration values for the upper and lower soil depths are 418ppm and 404.36ppm respectively. Water extractable analysis results verify the degree of leaching of the metals from anthropogenic source. Geoaccumulation index confirms that the two soil depths are similarly categorized as very heavily contaminated with (As, Cr, Co and Ni and moderately to heavily contaminated with (Cu, Pb and Mo whereas the top part is moderately contaminated with Zn. Based on Enrichment Factor (EF, both soil depths have moderate enrichment with Pb ( 2 EF >20, very high enrichment with Cr (2040. The severe contamination is evident to the east western direction towards which the wind blow predominantly.

  20. Trabalho e saúde: a atividade da queima de resíduos tóxicos em fornos de cimenteiras de Cantagalo, Rio de Janeiro Work and health: the activity of burning toxic waste in cement kilns in Cantagalo, Rio de Janeiro State

    Directory of Open Access Journals (Sweden)

    Afrânio Gomes Pinto Júnior

    2009-12-01

    Full Text Available Este estudo ocupa-se de analisar as condições de trabalho e saúde a partir dos relatos dos trabalhadores envolvidos na atividade de coprocessamento de resíduos tóxicos em fornos de cimenteiras de Cantagalo (RJ. Realizamos uma investigação qualitativa baseada na utilização de roteiro semi-estruturado, na qual foram entrevistados treze indivíduos. Na análise do discurso, foi possível observar falhas no planejamento do processo de trabalho, na identificação de riscos, na prevenção de agravos, no monitoramento de impactos à saúde e ao ambiente, bem como na identificação e notificação aos órgãos competentes. A assimilação das incertezas do processo, favorecendo os interesses dos empreendedores, permitiu que recaísse sobre os trabalhadores o ônus do adoecimento, aceitável na medida em que se negam evidências clínicas. Torna-se imperioso amplo debate que envolva entes públicos e privados, a sociedade e suas representações, confrontando-se questões éticas, ambientais e de saúde aos interesses do capital, para que se estabeleçam novas diretrizes para o processo.This study analyzes the work and health conditions through the discourse of the employees involved in the activity of toxic waste co-processing in cement kilns in Cantagalo, RJ. A qualitative approach was adopted using a semi-structured interview with 13 individuals. After analyzing the discourse, it was possible to observe relevant failures in the work process planning, in the identification of risks, in preventing diseases, in monitoring health impacts and to the environment, even their identification and notification to the competent authorities. The assimilation of the uncertainties of the process, favoring the interests of the entrepreneurs, has passed on the workers the burden of illness, rendered acceptable in that they deny clinical evidences. It is imperative to establish a broad debate involving public and private entities, the society in all its

  1. High-Temperature Release of SO2 from Calcined Cement Raw Materials

    DEFF Research Database (Denmark)

    Nielsen, Anders Rooma; Larsen, Morten B.; Glarborg, Peter

    2011-01-01

    During combustion of alternative fuels in the material inlet end of cement rotary kilns, local reducing conditions may occur and cause reductive decomposition of sulfates from calcined cement raw materials. Decomposition of sulfates is problematic because it increases the gas-phase SO2...... concentration, which may cause deposit formation in the kiln system. In this study, the release of sulfur from calcined cement raw materials under both oxidizing and reducing conditions is investigated. The investigations include thermodynamic equilibrium calculations in the temperature interval of 800–1500 °C...... and experiments in a tube furnace reactor in the temperature interval of 900–1100 °C. The investigated conditions resemble actual conditions in the material inlet end of cement rotary kilns. It was found that the sulfates CaSO4, K2SO4, and Na2SO4 were all stable under oxidizing conditions but began to decompose...

  2. Coal desulfurization in a rotary kiln combustor

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, J.T. Jr.

    1992-09-11

    The purpose of this project was to demonstrate the combustion of coal and coal wastes in a rotary kiln reactor with limestone addition for sulfur control. The rationale for the project was the perception that rotary systems could bring several advantages to combustion of these fuels, and may thus offer an alternative to fluid-bed boilers. Towards this end, an existing wood pyrolysis kiln (the Humphrey Charcoal kiln) was to be suitably refurbished and retrofitted with a specially designed version of a patented air distributor provided by Universal Energy, Inc. (UEI). As the project progressed beyond the initial stages, a number of issues were raised regarding the feasibility and the possible advantages of burning coals in a rotary kiln combustor and, in particular, the suitability of the Humphrey Charcoal kiln as a combustor. Instead, an opportunity arose to conduct combustion tests in the PEDCO Rotary Cascading-Bed Boiler (RCBB) commercial demonstration unit at the North American Rayon CO. (NARCO) in Elizabethton, TN. The tests focused on anthracite culm and had two objectives: (a) determine the feasibility of burning anthracite culms in a rotary kiln boiler and (b) obtain input for any further work involving the Humphrey Charcoal kiln combustor. A number of tests were conducted at the PEDCO unit. The last one was conducted on anthracite culm procured directly from the feed bin of a commercial circulating fluid-bed boiler. The results were disappointing; it was difficult to maintain sustained combustion even when large quantities of supplemental fuel were used. Combustion efficiency was poor, around 60 percent. The results suggest that the rotary kiln boiler, as designed, is ill-suited with respect to low-grade, hard to burn solid fuels, such as anthracite culm. Indeed, data from combustion of bituminous coal in the PEDCO unit suggest that with respect to coal in general, the rotary kiln boiler appears inferior to the circulating fluid bed boiler.

  3. Scrap tire ashes in portland cement production

    Directory of Open Access Journals (Sweden)

    Mónica Adriana Trezza

    2009-01-01

    Full Text Available Scrap tires are not considered harmful waste, but their stocking and disposal are a potential health and environmental risk. Properly controlled calcinations at high temperatures make tire combustion an interesting alternative due to its high calorific power, comparable to that of fuel-oil. Consequently, using them as an alternative combustible material in cement kilns makes it possible to give it a valuable use. However, it remains to be assured whether the impurities added to the clinker through these fuels do not affect its structure or properties.This paper shows the studies carried out on different clinkers under laboratory conditions with different levels of addition of scrap tire ashes, added by partially replacing traditional fuel in cement kilns.

  4. Combustion of solid alternative fuels in the cement kiln burner

    OpenAIRE

    Nørskov, Linda Kaare; Dam-Johansen, Kim; Glarborg, Peter; Jensen, Peter Arendt; Larsen, Morten Boberg

    2012-01-01

    I cementindustrien er der en øget miljømœssig og økonomisk motivation for at erstatte konventionelle fossile brœndsler med alternative brœndsler; biomasse og affald. Indførelsen af alternative brœndsler kan dog påvirke emissioner, cementproduktkvalitet, processtabilitet og -effektivitet. I kalcinatoren er substitutionen med alternative brœndsler nået tœt på 100% på mange cementanlœg, og for at øge anvendelsen af alternative brœndsler yderligere må substitutionen i roterovnen øges. Der er begr...

  5. Combustion of large solid fuels in cement rotary kilns

    OpenAIRE

    2012-01-01

    Cementindustrien har en stor interesse i at erstatte fossile brændsler med alternative brændsler, med henblik på at minimere omkostninger og reducere CO2-emissioner. Disse alternativebrændsler er primært faste brændsler som affaldsbaserede brændsler (RDF), brugte dæk (TDF), kød- og benmel (MBM), træaffald, kloakslam, papir, pap og plastic. Alternativ brændsels andelen af den totale energi varierer meget fra region til region, men generelt er der en tendens til stigende anvendelse af alternati...

  6. 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...

  7. Cement Conundrum

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China aims to streamline the crowded cement industry Policymakers are looking to build a concrete wall around the cement-making industry as they seek to solidify the fluid cement market and cut excessive production.

  8. Leaching of metals from cement under simulated environmental conditions.

    Science.gov (United States)

    Lu, Huixia; Wei, Fang; Tang, Jingchun; Giesy, John P

    2016-03-15

    Leaching of metals from cement under various environmental conditions was measured to evaluate their environmental safety. A cement product containing clinker, which was produced from cement kiln co-processing of hazardous wastes, was solidified and leaching of metals was characterized using the 8-period test. Concentrations and speciation of metals in cements were determined. Effects of ambient environment and particle size on leachability of metals and mineralogical phases of cement mortars were evaluated by use of XRD and SEM. Results indicated that metals in cements were leachable in various media in descending order of: sea water, groundwater and acid rain. Cr, Ni, As, Co and V were leached by simulated sea water, while Cu, Cd, Pb, Zn, Mn, Sb and Tl were not leached in simulated sea water, groundwater or acid rain. When exposed to simulated acid rain or groundwater, amounts of Cr, Ni, As and V leached was inversely proportional to particle size of cement mortar. According to the one-dimensional diffusion equation, Cr was most leachable and the cumulative leached mass was predicted to be 9.6 mg kg(-1) after 20 years. Results of this study are useful in predicting releases of metals from cement products containing ash and clinkers cement kiln co-processing of hazardous wastes, so that they can be safely applied in the environment.

  9. 预分解窑熟料煅烧%Burning Clinker in the Precalcining Kiln

    Institute of Scientific and Technical Information of China (English)

    冯晓梅

    2011-01-01

    Basic production proccss of the silicatc cement are to make raw meal;burning clinker and making into cement.The burning clinker is the core of cement preduction.The rotary kiln is main equipment of the burning clinker system,it consists of the tube-shaped object,support installation.driving installation and seal up installation etc.%硅酸盐水泥的基本生产过程是生料制备、熟料煅烧和水泥制成.熟料煅烧是水泥厂生产的核心,回转窑是熟料煅烧系统中的主要设备,回转窑主要由筒体、支承装置,传动装置、密封装置等组成.

  10. Analysis of Energy-Efficiency Opportunities for the Cement Industry in Shandong Province, China

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn; Hasanbeigi, Ali; Lu, Hongyou; Wang, Lan

    2009-10-01

    China's cement industry, which produced 1,388 million metric tons (Mt) of cement in 2008, accounts for almost half of the world's total cement production. Nearly 40% of China's cement production is from relatively obsolete vertical shaft kiln (VSK) cement plants, with the remainder from more modern rotary kiln cement plants, including plants equipped with new suspension pre-heater and pre-calciner (NSP) kilns. Shandong Province is the largest cement-producing Province in China, producing 10% of China's total cement output in 2008. This report documents an analysis of the potential to improve the energy efficiency of NSP kiln cement plants in Shandong Province. Sixteen NSP kiln cement plants were surveyed regarding their cement production, energy consumption, and current adoption of 34 energy-efficient technologies and measures. Plant energy use was compared to both domestic (Chinese) and international best practice using the Benchmarking and Energy Saving Tool for Cement (BEST-Cement). This benchmarking exercise indicated an average technical potential primary energy savings of 12% would be possible if the surveyed plants operated at domestic best practice levels in terms of energy use per ton of cement produced. Average technical potential primary energy savings of 23% would be realized if the plants operated at international best practice levels. Energy conservation supply curves for both fuel and electricity savings were then constructed for the 16 surveyed plants. Using the bottom-up electricity conservation supply curve model, the cost-effective electricity efficiency potential for the studied cement plants in 2008 is estimated to be 373 gigawatt hours (GWh), which accounts for 16% of total electricity use in the 16 surveyed cement plants in 2008. Total technical electricity-saving potential is 915 GWh, which accounts for 40% of total electricity use in the studied plants in 2008. The fuel conservation supply curve model shows the total

  11. Destruction of meat and bone meals in cement plants; Destruction des farines animales dans les cimenteries

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-10-01

    Following the crisis of the bovine spongiform encephalopathy disease ('mad cow' disease), the French cement industrialists have been requested by the government since 1996 to eliminate the forbidden meat and bone meals in cement kilns where they are used as fuel substitutes. This article presents the advantages of the cement industry file in the destruction of such wastes, the validation and the safety aspects of this process. Meat and bone meal represents a high-grade fuel that lowers the environmental impact of cement production and does not affect the quality of cement. (J.S.)

  12. 7 CFR 300.2 - Dry Kiln Operator's Manual.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Dry Kiln Operator's Manual. 300.2 Section 300.2... SERVICE, DEPARTMENT OF AGRICULTURE INCORPORATION BY REFERENCE § 300.2 Dry Kiln Operator's Manual. (a) The Dry Kiln Operator's Manual, which was published in August 1991 as Agriculture Handbook No. 188 by...

  13. Mass transfer in rolling rotary kilns : a novel approach

    NARCIS (Netherlands)

    Heydenrych, M.D.; Greeff, P.; Heesink, A. Bert M.; Versteeg, G.F.

    2002-01-01

    A novel approach to modeling mass transfer in rotary kilns or rotating cylinders is explored. The movement of gas in the interparticle voids in the bed of the kiln is considered, where particles move concentrically with the geometry of the kiln and gas is entrained by these particles. The approach c

  14. 27 CFR 9.27 - Lime Kiln Valley.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lime Kiln Valley. 9.27... OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.27 Lime Kiln Valley. (a) Name. The name of the viticultural area described in this section is “Lime Kiln...

  15. Comparative Analysis of Air Emission from Cement Plant Using TDF as Partial Substitute for Coal

    OpenAIRE

    2014-01-01

    Tyre derived fuel (TDF) has a potential advantage for its use as a co-fuel with coal in rotary kilns of cement plants.  In this study we analyzed the emissions of selected criteria pollutants; CO2, CO, NOx, SOx and PM to suggest suitable proportion of TDF to replace coal when different proportions of TDF and coal were used as cement kiln feed. Emissions of CO2, CO, NO, NO2, SO2 and total PM from stack and concentrations of CO, NOx, SOx and PM10 in ambient air were assessed using USEPA recomme...

  16. Design Robust Controller for Rotary Kiln

    Directory of Open Access Journals (Sweden)

    Omar D. Hernández-Arboleda

    2013-11-01

    Full Text Available This paper presents the design of a robust controller for a rotary kiln. The designed controller is a combination of a fractional PID and linear quadratic regulator (LQR, these are not used to control the kiln until now, in addition robustness criteria are evaluated (gain margin, phase margin, strength gain, rejecting high frequency noise and sensitivity applied to the entire model (controller-plant, obtaining good results with a frequency range of 0.020 to 90 rad/s, which contributes to the robustness of the system.

  17. Analysis on occupational exposure levels and control effectiveness of dust in cement production line of new dry method%新型干法水泥生产线粉尘职业暴露水平及控制效果

    Institute of Scientific and Technical Information of China (English)

    王德军; 隋少峰; 孔凡玲; 黄东海

    2012-01-01

    Objective To investigate the occupational exposure levels of dust in new suspension preheater dry process (NSP) cement production line and put forward rectification measures for dust-exposed posts,and to provide ideas for the modern cement production enterprises in dust control and occupational health management.Methods Occupational health field investigation combined with field test were used to measure the time-weighted average concentration (CTWA) of the dust in the workplace.Rectification measures were taken for the dust-exposed posts with unqualified dust concentration,and the protective effects of dustproof facilities in the rectified workplace were evaluated.Results The field investigation revealed incompletely closed dustproof facilities,improperly set dust hoods,excess of dust leakage points,and other problems in the dust-exposed posts of an NSP cement production line before rectification,and the dustproof facilities could hardly exert dust removal effect.The field test showed that the vast majority of dust-exposed posts had the dust concentrations exceeding the occupational exposure limits (OELs),with a qualified rate as low as 31.8%.A series of rectification measures were taken for these posts.After the rectification,the dust-exposed posts demonstrated dramatically dropped CTWA,and the qualified rate of dust concentration in the dust-exposed posts rose to 90.9%.Conclusion The dust hazards in NSP cement production line cannot be ignored.Taking appropriate protective measures are critical for curbing dust hazards in modern cement production.%目的 了解新型干法水泥生产线粉尘职业暴露水平,提出整改治理措施,为现代水泥生产企业的粉尘治理及职业卫生管理提供思路.方法 采用职业卫生现场调查和现场检测相结合的方法,测定工作场所粉尘时间加权平均浓度(CTWA),对粉尘浓度不合格的作业岗位进行整改治理,评估整改粉尘作业场所防尘设施的防护效果.结果

  18. Analysis on the source of raw material of the celadon bodies from Zhanggongxiang kiln and Qingliangsi kiln by PIXE

    Institute of Scientific and Technical Information of China (English)

    ZHAO Weijuan; GUO Musen; JIN Wenqing; LI Guoxia; XIE Jianzhong; Guo Min; Lu Xiaoke; GAO Zhengyao; CHEN Huansheng; Zhang Bin; SUN Xinmin

    2004-01-01

    The proton induced X-ray emission (PIXE) is used to measure the chemical ingredients of seven main elements of each sample of celadon body from Qingliangsi kiln in Baofeng County and Zhanggongxiang kiln in Ruzhou City.The PIXE data are then analyzed by fuzzy cluster method,and the trend cluster diagram is obtained to determine their relation of classification and provenance. The result shows that the producing area of raw material of Ru porcelain bodies is concentrated in Qingliangsi kiln, while that of celadon bodies is slightly scattered in Zhanggongxiang kiln. The raw material origin of Ru porcelain bodies from Qingliangsi kiln in Baofeng County is different from that of Zhanggongxiang kiln in Ruzhou City. The materials of Ru Guan porcelain bodies and Ru Civil porcelain bodies in Qingliangsi kiln are basically the same.

  19. Assessment of air pollutant emissions from brick kilns

    Science.gov (United States)

    Rajarathnam, Uma; Athalye, Vasudev; Ragavan, Santhosh; Maithel, Sameer; Lalchandani, Dheeraj; Kumar, Sonal; Baum, Ellen; Weyant, Cheryl; Bond, Tami

    2014-12-01

    India has more than 100,000 brick kilns producing around 250 billion bricks annually. Indian brick industry is often a small scale industry and third largest consumer of coal in the country. With the growing demand for building materials and characterised by lack of pollution control measures the brick industry has a potential to cause adverse effects on the environment. This paper presents assessment of five brick making technologies based on the measurements carried out at seventeen individual brick kilns. Emissions of PM, SO2, CO and CO2 were measured and these emissions were used to estimate the emission factors for comparing the emissions across different fuel or operating conditions. Estimated emission from brick kilns in South Asia are about 0.94 million tonnes of PM; 3.9 million tonnes of CO and 127 million tonnes of CO2 per year. Among various technologies that are widely used in India, Zig zag and vertical shaft brick kilns showed better performance in terms of emissions over the traditional fixed chimney Bull's trench kilns. This suggests that the replacement of traditional technologies with Zig zag, vertical shaft brick kilns or other cleaner kiln technologies will contribute towards improvements in the environmental performance of brick kiln industry in the country. Zig zag kilns appear to be the logical replacement because of low capital investment, easy integration with the existing production process, and the possibility of retrofitting fixed chimney Bull's trench kilns into Zig zag firing.

  20. Thermal monitoring at E-Sheng cement in China; Waermeueberwachung bei E-Sheng Cement in China

    Energy Technology Data Exchange (ETDEWEB)

    Idoux, Maurice [HGH Infrared Systems, Igny (France)

    2011-07-01

    The E-Sheng cement plant is situated 130 km South East of Chengdu, capital city of Sichuan Province. It is in an environmentally protected area and as such, it is subject to stringent regulations as far as pollution is concerned. The quarry is situated 5 km away on a hillside, 500 m above plant level. Transport of limestone is by one single conveyor. The plant has 5 identical kilns, each 5500 tpd, i.e. 27 500 tpd total output, making it the largest single plant in the southwest of China. The plant was designed by the Nanjing Cement Institute (NCDRI). Its specific heat consumption is 730 kcal/kg of clinker, 65% at the precalciner and 35% at the kiln. Each kiln is 4.8 m dia x 74 m long. Start-up fuel is oil, main fuel is coal, 5500 kcal/kg LHV. The coal mine is 25 km away; coal delivery to the plant is by road. The plant is checked regularly for emissions, management of the plant is particularly advanced and the staff is well trained, thus achieving at high quality product. The total number of employees is 3000. 15% of the production is sold in bags, the rest in bulk. Delivery to clients is by road or rail. The first line was commissioned in 2008, the last in 2010. Due to the 2008 earthquake 300 km away, local demand for cement remains high. Each kiln is equipped with a hig resolution scanner which warns the operator of any refractory lining/coating problems and possible malfunction of the kiln. (orig.)

  1. 2015年度石灰回转窑技术发展报告%Report of technical development of lime rotary kiln in 2015

    Institute of Scientific and Technical Information of China (English)

    乔斌; 张凯博

    2016-01-01

    简要论述了活性石灰的主要需求行业———钢铁行业和电石行业的2015年度发展状况,总结了2015年度石灰回转窑的技术创新情况及石灰回转窑发展中存在的主要问题,并对2016年的回转窑技术发展进行了展望。指出石灰回转窑在余热回收利用、水泥回转窑技术改造及石灰回转窑智能化工厂建设等方面的发展空间巨大。%This paper discusses the development of the major demand industries—iron and steel industry and calcium carbide industry of active lime in the year of 2015,and summarizes the technical innovation and major problems in the development of lime rotary kiln in 2015,then forecasts the tech-nical development of rotary kiln in the year of 2016. Meanwhile it points that there is significant room for recycling utilization of exhaust heat of the lime rotary kiln,technical improvement of cement rotary kiln and construction of intelligent factory of lime rotary kiln and so on.

  2. The impact of staged combustion on the operation of a precalciner cement klin

    OpenAIRE

    Tokheim, Lars-André

    1999-01-01

    In this thesis, the impact of staged combustion on the operation of a precalciner cement kiln, is considered. Mathematical modelling and full-scale experiments at the Norcem cement works in Brevik, Norway, is the basis for the thesis. The goal of the work was to characterize and explain operational disturbances related to the application of alternative solid fuels in staged combustion, and to take actions to avoid such disturbances. A mass and energy balance of a precalciner...

  3. Digital Kilns and Furnaces——the Development Direction of Industrial Kilns and Furnaces in the 21st Century

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaoming; HUANG Zhichu; ZHANG Jiafan

    2006-01-01

    The digital manufacturing theory is applied to the special manufacturing equipments--industrial kilns and furnaces; the concept of digital kilns & furnaces is put forward. The present status of research and application for digital technologies in fuel industrial kilns & furnaces is also introduced. Then, take the case of gas fuel kilns & furnaces, their main key technical issues are discussed. Digital kilns & furnaces as an important constituent of the digital equipments are the crucial base of the digital manufacturing. The value of research on digital kilns & furnaces and the application prospect are undoubted. It will improve product quality, reduce the manpower cost, enhance product market competitive ability, promote comprehensively tradition industries such as ceramics, metallurgy industry,and so on.

  4. Cement plant gaseous pollutant emission reduction technologies

    Directory of Open Access Journals (Sweden)

    Andrés Emilio Hoyos Barreto

    2010-10-01

    Full Text Available A brief description of SOX, NOX and CO2 formation is presented, these being the main pollutants emitted in the cement industry gas stream Several technologies for reducing NOX, SOX and CO2 emissions in long wet kilns are introduced: primary measures preventing contaminant formation and secondary/tube end emission reduction measures. Strategies for preventing CO2 (green-house effect gas formation are also addressed, such as fuel and raw material substitution and CO2 capture technologies which are still being developed.

  5. 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

  6. Impact of ancient charcoal kilns on chemical properties of several forest soils after 2 centuries

    Science.gov (United States)

    Dufey, Joseph; Hardy, Brieuc; Cornelis, Jean-Thomas

    2014-05-01

    Pyrogenic carbon plays a major role in soil biogeochemical processes and carbon budgets. Until the early 19th century, charcoal was the unique combustible used for iron metallurgy in Wallonia (Belgium). Traditional charcoal kilns were built directly in the forest: wood logs were piled into a mound and isolated from air oxygen with a covering of vegetation residues and soil before setting fire, inducing wood pyrolysis. Nowadays, ancient wood-charring platforms are still easy to identify on the forest floor as heightened domes of 10 meters in diameter characterized by a very dark topsoil horizon containing charcoal dust and fragments. Our goal is to assess the effects of wood charring at mound kiln sites on the properties of various forest soil types in Wallonia (Belgium), after two centuries. We sampled soil by horizon in 18 ancient kiln sites to 1.20 meter depth. The adjacent charcoal-unaffected soils were sampled the same way. We also collected recent charcoal fragments and topsoil samples from a still active charcoal kiln located close to Dole (France) to apprehend the evolution of soil properties over time. The pH, total carbon (C) and nitrogen (N) content, available phosphorus (Pav), cation exchange capacity at pH 7 (CEC), exchangeable cations (Ca++, Mg++, K+, Na+) and loss on ignition at 550°C (LI550) were measured on each soil sample. We separated the soil profiles in 5 groups based on the nature of soil substrate and pedogenesis for interpretation of the results. We show that the total carbon stock is significantly increased at kiln sites due to higher C concentrations and greater depth of the organo-mineral horizon. The C/N ratio in charcoal-enriched soil horizons is significantly higher than in the neighboring reference soils but clearly attenuated compared to pure wood-charcoal fragments. The CEC is higher in the charcoal-enriched soil horizons, not only due to higher C concentrations but also to increased CEC by carbon unit at kiln sites. The high

  7. By-product materials in cement clinker manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Gadayev, A. [ICS and E, Aurora, CO (United States); Kodess, B. [VNIIMS Gosstandart of Russia, Moscow (Russian Federation)

    1999-02-01

    The use of Cl- and SO{sub 3}-containing by-products from chemical industries for manufacturing Portland cement clinker using a wet process was examined. The chemical and mineralogical compositions of the by-products and raw materials were determined. Homogeneous raw mixes containing different concentrations of by-products (5--30%) were prepared and the influence of the by-products on all steps of burning the mixes in a kiln to form a cement clinker was investigated. It was shown that introducing Cl- and SO{sub 3}-containing by-products to the raw mixes significantly changes all the cement clinker producing stages and changes the chemical and mineralogical compositions at all intermediate stages and in the finished products, forming new minerals containing Cl and SO{sub 3} [CaO{sub x} (SiO{sub 2}){sub y} CaCl{sub 2}] or [CaO{sub x} (SiO{sub 2}){sub y} CaSO{sub 4}] and increasing the amount of well-known intermediate minerals. The presence of the chlorides and sulfates in the cement clinker burning processes removes alkali from the raw mixes, turning them to volatile forms, accelerating the raw mineral decomposition processes and accelerating the formation processes of cement minerals (C{sub 2}S, C{sub 12}A{sub 7}, C{sub 4}AF) and formation of chloride and sulfate cycles in the kiln, forming clinker liquids and decreasing the formation and growth of the main cement minerals (C{sub 3}A, C{sub 3}S). The cement clinker contains some quantity of minerals with Cl or SO{sub 3}. Their presence in the final product decreases cement quality by reducing the amount of active CaO (C) and reducing the active CaO/SiO{sub 2} ratio.

  8. CO2 REDUCTION OPTIONS IN CEMENT INDUSTRY - THE NOVI POPOVAC CASE

    Directory of Open Access Journals (Sweden)

    Gordana M Stefanović

    2010-01-01

    Full Text Available The cement industry contributes about 5% to global anthropogenic CO2 emissions, and is thus an important sector in CO2-emission mitigation strategies. Carbon dioxide is emitted from the calcination process of limestone, from combustion of fuels in the kiln, and from the coal combustion during power generation. Strategies to reduce these CO2 emissions include energy efficiency improvement, new processes, shift to low carbon fuels or waste fuels in cement production, increased use of additives in cement production, alternative cements, and CO2 removal from flue gases in clinker kilns. Increased use of fly ash as an additive to cement and concrete has a number of advantages, the primary being reduction of costs of fly ash disposal, resource conservation, and cost reduction of the product. Since the production of cement requires a large amount of energy (about 2.9-3.2 GJt-1, the substitution of cement by fly ash saves not only energy but also reduces the associated greenhouse gas emissions. The paper evaluates the reduction of CO2 emissions that can be achieved by these mitigation strategies, as well as by partial substitution of cement by fly ash. The latter is important because the quality of the produced concrete depends on the physical-chemical properties of the fly ash and thus partial substitution as well as the type of fly ash (e.g., the content of CaO has an effect not only on energy consumption and emissions, but also on the produced concrete quality.

  9. Community Geothermal Technology Program: Experimental lumber drying kiln. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Leaman, D.; Irwin, B.

    1989-10-01

    Goals were to demonstrate feasibility of using the geothermal waste effluent from the HGP-A well as a heat source for a kiln operation to dry hardwoods, develop drying schedules, and develop automatic systems to monitor/control the geothermally heated lumber dry kiln systems. The feasibility was demonstrated. Lumber was dried in periods of 2 to 6 weeks in the kiln, compared to 18 months air drying and 6--8 weeks using a dehumidified chamber. Larger, plate-type heat exchangers between the primary fluid and water circulation systems may enable the kiln to reach the planned temperatures (180--185 F). However, the King Koa partnership cannot any longer pursue the concept of geothermal lumber kilns.

  10. [Environment load from China's cement production].

    Science.gov (United States)

    Zhu, Tian-le; He, Wei; Zeng, Xiao-lan; Huang, Xin; Ma, Bao-guo

    2006-10-01

    Based on the life-cycle theory, a quantitative evaluation of the environment load caused by cement manufacturing in China was carried out with the application of the CML. environmental impact assessment method. The results show that global warming potential, energy depletion potential and abiotic depletion potential make the main contribution to the environment impact, their environmental loads corresponding to identical environmental impact sorts being 2.76%, 2.34% and 1.39% of the overall load of the whole world, respectively. In 2004, the environment load from cement manufacturing in China is roughly 1.28% of the overall load of the whole world, in which the environmental loads from the shaft kiln processing, wet rotary processing and new-type dry processing being 0.84%, 0.12% and 0.32%, respectively. And it can be reduced to about 1% by replacing backward production processes with the dry method production process.

  11. Experimental study on improving cement quality with oxygen- enriched combustion technology

    Science.gov (United States)

    Liu, Y. Q.; Zhang, A. M.; Qing, S.; Li, F. S.; Yang, S. P.; Yang, Z. F.

    2015-12-01

    With the intensification of the global energy crisis, the production cost of enterprises is continuously increasing because of the rising fuel prices and high requirements for environmental protection. As result, energy savings and environmental protection are vital considerations for a variety of enterprises. As a practical energy-saving technology, oxygen- enriched combustion has played a major role in energy saving and emissions reduction as its application in industrial furnaces has been popularized in recent years. This experiment was conducted in a cement rotary kiln with a capacity of 4000 t/d in a factory in China. Based on measured data in the oxygen-enriched combustion experiment, we determined the patterns of variation in the main parameters of the cement rotary kiln under oxygen-enriched production conditions. The results provide important theoretical and practical base for the cement building materials industry in energy saving and emissions reduction.

  12. The effect of fly ash and coconut fibre ash as cement replacement materials on cement paste strength

    Science.gov (United States)

    Bayuaji, R.; Kurniawan, R. W.; Yasin, A. K.; Fatoni, H. AT; Lutfi, F. M. A.

    2016-04-01

    Concrete is the backbone material in the construction field. The main concept of the concrete material is composed of a binder and filler. Cement, concrete main binder highlighted by environmentalists as one of the industry are not environmentally friendly because of the burning of cement raw materials in the kiln requires energy up to a temperature of 1450° C and the output air waste CO2. On the other hand, the compound content of cement that can be utilized in innovation is Calcium Hydroxide (CaOH), this compound will react with pozzolan material and produces additional strength and durability of concrete, Calcium Silicate Hydrates (CSH). The objective of this research is to explore coconut fibers ash and fly ash. This material was used as cement replacement materials on cement paste. Experimental method was used in this study. SNI-03-1974-1990 is standard used to clarify the compressive strength of cement paste at the age of 7 days. The result of this study that the optimum composition of coconut fiber ash and fly ash to substitute 30% of cement with 25% and 5% for coconut fibers ash and fly ash with similar strength if to be compared normal cement paste.

  13. Glass recycling in cement production--an innovative approach.

    Science.gov (United States)

    Chen, Guohua; Lee, Harry; Young, King Lun; Yue, Po Lock; Wong, Adolf; Tao, Thomas; Choi, Ka Keung

    2002-01-01

    An innovative approach of using waste glass in cement production was proposed and tested in a laboratory and cement production plant. The laboratory characterization of 32 types of glass show that the chemical composition of glass does not vary significantly with its color or origin but depends on its application. The alkali content of glass, a major concern for cement production varies from 0 to 22%. For the glass bottles mainly found in Hong Kong waste glasses, the alkali content (Na2O) ranges from 10 to 19% with an average around 15%. There is no significant change of the SO2 content in the gas exhaust of the rotary kiln when about 1.8 t/h of glass bottles were loaded along with the 280-290 t/h raw materials. The content of NOx, mainly depends on the temperature of the kiln, does not show significant change either. The SO3 content of the clinker is comparable with that obtained without the loading of glass. The alkaline content shows a slight increase but still within three times the standard deviation obtained from the statistical data of the past year. The detailed analysis of the quality of the cement product shows that there is not any significant impact of glass for the feeding rate tested.

  14. Effect of cement industry pollution on chlorophyll content of some crops at Kodinar, Gujarat, India

    OpenAIRE

    2013-01-01

    Study was carried out to assess the impact of cement industry pollution on some selected plant species around cement industry. Effect of cement dust on chlorophyll was studied in Arachis hypogaea, Sesamum indicum and Triticum species. Sampling was done at different distance like 0.5 km, 1.0 km and 2.0 km from the cement industry. The Chlorophyll pigments were reduced in dust-exposed plant species compared with control site Pransli (15 km away from the cement industry). Changes in chlorophyll ...

  15. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1994-12-01

    Full Text Available During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production, pipe corrosion and expensive well repairs. Cementing temperature conditions are important because bot-tomhole circulating temperatures affect slurry thickening time, arheology, set time and compressive strength development. Knowing the actual temperature which cement encounters during placement allows the selection of proper cementing materials for a specific application. Slurry design is affected by well depth, bottom hole circulating temperature and static temperature, type or drilling fluid, slurry density, pumping time, quality of mix water, fluid loss control, flow regime, settling and free water, quality of cement, dry or liquid additives, strength development, and quality of the lab cement testing and equipment. Most Portland cements and Class J cement have shown suitable performances in geot-hermal wells. Cement system designs for geothermal wells differ from those for conventional high temperature oil and gas wells in the exclusive use of silica flour instead of silica sand, and the avoidance of fly ash as an extender. In this paper, Portland cement behaviour at high temperatures is described. Cement slurry and set cement properties are also described. Published in literature, the composition of cement slurries which were tested in geothermal conditions and which obtained required compressive strength and water permeability are listed. As a case of our practice geothermal wells Velika Ciglena-1 and Velika Ciglena-la are described.

  16. Integrated Environmental Quality Assessments of Surface Water around Obajana Cement Production Area

    Directory of Open Access Journals (Sweden)

    E.G. Ameh

    2014-04-01

    Full Text Available Due to industrialization, there is enormous amount of heavy metals been released from anthropogenic sources into the environment. Heavy metals are considered as one of the main sources of environmental pollution since they have significant effect on the ecological quality and water in particular. These pollutants are hazardous to consumers of water that have significant quantity of these heavy metals. The population most exposed to cement polluted water includes workers in cement factories, families of workers living in Staff houses of factories like in Obajana and other neighborhood habitations. The Obajana cement factory consists of cement kilns/coolers with clinkers. The kilns are equipped with pre-heaters and Electro-Static Precipitators (ESP. The facility has raw mills, crushing operations, cement mills that are potential source of pollutants into the water bodies. Storage silos, conveyors, vehicular travel, and other unquantified fugitive source of water contamination exist in the factory. Monitoring the contamination of water with respect to heavy metals is of interest due to their influence on humans, animals and to some extent plants. A good approach to estimate how much of the water is impacted is by using the heavy metal pollution index and metal index for metal concentrations above the control points in water bodies around Obajana cement.

  17. Opportunities for Energy Efficiency and Demand Response in the California Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Daniel; Goli, Sasank; Faulkner, David; McKane, Aimee

    2010-12-22

    This study examines the characteristics of cement plants and their ability to shed or shift load to participate in demand response (DR). Relevant factors investigated include the various equipment and processes used to make cement, the operational limitations cement plants are subject to, and the quantities and sources of energy used in the cement-making process. Opportunities for energy efficiency improvements are also reviewed. The results suggest that cement plants are good candidates for DR participation. The cement industry consumes over 400 trillion Btu of energy annually in the United States, and consumes over 150 MW of electricity in California alone. The chemical reactions required to make cement occur only in the cement kiln, and intermediate products are routinely stored between processing stages without negative effects. Cement plants also operate continuously for months at a time between shutdowns, allowing flexibility in operational scheduling. In addition, several examples of cement plants altering their electricity consumption based on utility incentives are discussed. Further study is needed to determine the practical potential for automated demand response (Auto-DR) and to investigate the magnitude and shape of achievable sheds and shifts.

  18. Lunar cement

    Science.gov (United States)

    Agosto, William N.

    1992-01-01

    With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

  19. An assessment of gas-side fouling in cement plants

    Science.gov (United States)

    Marner, W. J.

    1982-01-01

    The cement industry is the most energy-intensive industry in the United States in terms of energy cost as a percentage of the total product cost. An assessment of gas-side fouling in cement plants with special emphasis on heat recovery applications is provided. In the present context, fouling is defined as the buildup of scale on a heat-transfer surface which retards the transfer of heat and includes the related problems of erosion and corrosion. Exhaust gases in the cement industry which are suitable for heat recovery range in temperature from about 100 to 1300 K, are generally dusty, may be highly abrasive, and are often heavily laden with alkalies, sulfates, and chlorides. Particulates in the exhaust streams range in size from molecular to about 100 micrometers in diameter and come from both the raw feed as well as the ash in the coal which is the primary fuel used in the cement industry. The major types of heat-transfer equipment used in the cement industry include preheaters, gas-to-air heat exchangers, waste heat boilers, and clinker coolers. At the present time, the trend in this country is toward suspension preheater systems, in which the raw feed is heated by direct contact with the hot kiln exit gases, and away from waste heat boilers as the principal method of heat recovery. The most important gas-side fouling mechanisms in the cement industry are those due to particulate, chemical reaction, and corrosion fouling.

  20. Potential for energy conservation in the cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Garrett-Price, B.A.

    1985-02-01

    This report assesses the potential for energy conservation in the cement industry. Energy consumption per ton of cement decreased 20% between 1972 and 1982. During this same period, the cement industry became heavily dependent on coal and coke as its primary fuel source. Although the energy consumed per ton of cement has declined markedly in the past ten years, the industry still uses more than three and a half times the fuel that is theoretically required to produce a ton of clinker. Improving kiln thermal efficiency offers the greatest opportunity for saving fuel. Improving the efficiency of finish grinding offers the greatest potential for reducing electricity use. Technologies are currently available to the cement industry to reduce its average fuel consumption per ton by product by as much as 40% and its electricity consumption per ton by about 10%. The major impediment to adopting these technologies is the cement industry's lack of capital as a result of low or no profits in recent years.

  1. Leaching Behavior of Heavy Metals from Cement Pastes Using a Modified Toxicity Characteristic Leaching Procedure (TCLP).

    Science.gov (United States)

    Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali

    2016-03-01

    As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH cement rotary kiln co-processing products.

  2. Alternative Fuel for Portland Cement Processing

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Anton K; Duke, Steve R; Burch, Thomas E; Davis, Edward W; Zee, Ralph H; Bransby, David I; Hopkins, Carla; Thompson, Rutherford L; Duan, Jingran; ; Venkatasubramanian, Vignesh; Stephen, Giles

    2012-06-30

    The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burn characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were conducted

  3. Stochastic Modelling and Self Tuning Control of a Continuous Cement Raw Material Mixing System

    Directory of Open Access Journals (Sweden)

    Hannu T. Toivonen

    1980-01-01

    Full Text Available The control of a continuously operating system for cement raw material mixing is studied. The purpose of the mixing system is to maintain a constant composition of the cement raw meal for the kiln despite variations of the raw material compositions. Experimental knowledge of the process dynamics and the characteristics of the various disturbances is used for deriving a stochastic model of the system. The optimal control strategy is then obtained as a minimum variance strategy. The control problem is finally solved using a self-tuning minimum variance regulator, and results from a successful implementation of the regulator are given.

  4. Operating experience with CFB technology for waste utilization at a cement production plant

    Energy Technology Data Exchange (ETDEWEB)

    Wirthwein, R.; Scur, P.; Scharf, K.F. [Rudersdorfer Zement GmbH, (Germany); Hirschfelder, H. [Lurgi Energie und Entsorgung GmbH, (Germany)

    2002-07-01

    The Rudersdorf cement plant in Germany strives for high environmental standards, a high quality product and low production costs. The plant was the first to use circulating fluidized bed (CFB) technology in combination with a cement kiln. The following objectives were defined for the CFB: (1) use of waste as a low-cost raw materials and fuel for cement production, (2) ensure good combustion conditions even when using low quality fuels, and (3) produce raw material components which can be homogeneously integrated into the cement kiln feed stream. A gasification process was developed for processing a diverse waste stream to produce lean gas for use as a secondary fuel along with an inert ash that serves as a raw material component. The CFB unit was put into service in 1996. Since its launch, various plant components and waste pre-processing equipment have been optimized. The CFB unit has an availability of more than 90 per cent, and can process 120,000 tpa of secondary fuels, 150,000 tpa of ash, and 50,000 tpa of other mineral residues. Its use has contributed significantly to fuel costs savings and improved environmental performance at the cement production plant. 9 figs.

  5. Lime Kiln Modeling. CFD and One-dimensional simulations

    Energy Technology Data Exchange (ETDEWEB)

    Svedin, Kristoffer; Ivarsson, Christofer; Lundborg, Rickard

    2009-03-15

    The incentives for burning alternative fuels in lime kilns are growing. An increasing demand on thorough investigations of alternative fuel impact on lime kiln performance have been recognized, and the purpose of this project has been to develop a lime kiln CFD model with the possibility to fire fuel oil and lignin. The second part of the project consists of three technical studies. Simulated data from a one-dimensional steady state program has been used to support theories on the impact of biofuels and lime mud dryness. The CFD simulations was carried out in the commercial code FLUENT. Due to difficulties with the convergence of the model the calcination reaction is not included. The model shows essential differences between the two fuels. Lignin gives a different flame shape and a longer flame length compared to fuel oil. Mainly this depends on how the fuel is fed into the combustion chamber and how much combustion air that is added as primary and secondary air. In the case of lignin combustion the required amount of air is more than in the fuel oil case. This generates more combustion gas and a different flow pattern is created. Based on the values from turbulent reaction rate for the different fuels an estimated flame length can be obtained. For fuel oil the combustion is very intense with a sharp peak in the beginning and a rapid decrease. For lignin the combustion starts not as intense as for the fuel oil case and has a smoother shape. The flame length appears to be approximately 2-3 meter longer for lignin than for fuel oil based on turbulent reaction rate in the computational simulations. The first technical study showed that there are many benefits of increasing dry solids content in the lime mud going into a kiln such as increased energy efficiency, reduced TRS, and reduced sodium in the kiln. However, data from operating kilns indicates that these benefits can be offset by increasing exit gas temperature that can limit kiln production capacity. Simulated

  6. Lime Kiln Modeling. CFD and One-dimensional simulations

    Energy Technology Data Exchange (ETDEWEB)

    Svedin, Kristoffer; Ivarsson, Christofer; Lundborg, Rickard

    2009-03-15

    The incentives for burning alternative fuels in lime kilns are growing. An increasing demand on thorough investigations of alternative fuel impact on lime kiln performance have been recognized, and the purpose of this project has been to develop a lime kiln CFD model with the possibility to fire fuel oil and lignin. The second part of the project consists of three technical studies. Simulated data from a one-dimensional steady state program has been used to support theories on the impact of biofuels and lime mud dryness. The CFD simulations was carried out in the commercial code FLUENT. Due to difficulties with the convergence of the model the calcination reaction is not included. The model shows essential differences between the two fuels. Lignin gives a different flame shape and a longer flame length compared to fuel oil. Mainly this depends on how the fuel is fed into the combustion chamber and how much combustion air that is added as primary and secondary air. In the case of lignin combustion the required amount of air is more than in the fuel oil case. This generates more combustion gas and a different flow pattern is created. Based on the values from turbulent reaction rate for the different fuels an estimated flame length can be obtained. For fuel oil the combustion is very intense with a sharp peak in the beginning and a rapid decrease. For lignin the combustion starts not as intense as for the fuel oil case and has a smoother shape. The flame length appears to be approximately 2-3 meter longer for lignin than for fuel oil based on turbulent reaction rate in the computational simulations. The first technical study showed that there are many benefits of increasing dry solids content in the lime mud going into a kiln such as increased energy efficiency, reduced TRS, and reduced sodium in the kiln. However, data from operating kilns indicates that these benefits can be offset by increasing exit gas temperature that can limit kiln production capacity. Simulated

  7. Analysis of the elemental composition of Tang Sancai from the four major kilns in China using EDXRF

    Science.gov (United States)

    Ma, Bo; Liu, Long; Feng, Song-Lin; Xu, Qing; Feng, Xiang-Qian

    2014-01-01

    Tang Sancai was widely used in the Tang Dynasty, and the study of this pottery provides information about the sociocultural aspects of the Tang people. To understand the characteristics of the different kilns for the production of Tang Sancai, Energy Dispersive X-ray Fluorescence (EDXRF) was used to analyze 174 Tang Sancai shards. These specimens were selected from four production centers in the Tang Dynasty, namely, the Huangye Kiln, the Huangbu Kiln, the Xing Kiln and the Liquanfang Kiln. The results demonstrate that the clay bodies from different kilns have varying compositions, and each kiln has a unique elemental fingerprint. Of the 17 elements analyzed, TiO2 and Fe2O3 had distinctly different contents in the samples from the Huangye Kiln and the Huangbu Kiln. For the Xing Kiln and the Huangye Kiln, the characteristic elements are Fe2O3 and MnO. For the Xing Kiln and the Huangbu Kiln, the most dissimilar elements are TiO2, MnO and ZnO. When the Principal Component Analysis (PCA) was employed, the data points for the Huangye Kiln, the Huangbu Kiln and the Xing Kiln fell into distinct areas. For the Liquanfang Kiln, the contents of Al2O3 and Fe2O3 in white-bodied samples are different from those of other colors, which indicates that at least two types of raw materials were used. When compared with the white-bodied samples from the other three kilns, the white-bodied samples from the Liquanfang Kiln were found to have compositions similar to those of the samples from the Huangye Kiln, rather than the Huangbu Kiln, although the latter is much closer geographically than the former. All the obtained data provide valuable scientific criteria for provenance identification for Tang Sancai of unknown origin.

  8. Analysis of the elemental composition of Tang Sancai from the four major kilns in China using EDXRF

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Bo; Liu, Long [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Feng, Song-Lin; Xu, Qing [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Feng, Xiang-Qian, E-mail: fengxq@ihep.ac.cn [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-01-15

    Tang Sancai was widely used in the Tang Dynasty, and the study of this pottery provides information about the sociocultural aspects of the Tang people. To understand the characteristics of the different kilns for the production of Tang Sancai, Energy Dispersive X-ray Fluorescence (EDXRF) was used to analyze 174 Tang Sancai shards. These specimens were selected from four production centers in the Tang Dynasty, namely, the Huangye Kiln, the Huangbu Kiln, the Xing Kiln and the Liquanfang Kiln. The results demonstrate that the clay bodies from different kilns have varying compositions, and each kiln has a unique elemental fingerprint. Of the 17 elements analyzed, TiO{sub 2} and Fe{sub 2}O{sub 3} had distinctly different contents in the samples from the Huangye Kiln and the Huangbu Kiln. For the Xing Kiln and the Huangye Kiln, the characteristic elements are Fe{sub 2}O{sub 3} and MnO. For the Xing Kiln and the Huangbu Kiln, the most dissimilar elements are TiO{sub 2}, MnO and ZnO. When the Principal Component Analysis (PCA) was employed, the data points for the Huangye Kiln, the Huangbu Kiln and the Xing Kiln fell into distinct areas. For the Liquanfang Kiln, the contents of Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} in white-bodied samples are different from those of other colors, which indicates that at least two types of raw materials were used. When compared with the white-bodied samples from the other three kilns, the white-bodied samples from the Liquanfang Kiln were found to have compositions similar to those of the samples from the Huangye Kiln, rather than the Huangbu Kiln, although the latter is much closer geographically than the former. All the obtained data provide valuable scientific criteria for provenance identification for Tang Sancai of unknown origin.

  9. Mercury enrichment and its effects on atmospheric emissions in cement plants of China

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Wu, Qingru; Hao, Jiming

    2014-08-01

    The cement industry is one of the most significant anthropogenic sources of atmospheric mercury emissions worldwide. In this study of three typical Chinese cement plants, mercury in kiln flue gas was sampled using the Ontario Hydro Method (OHM), and solid samples were analyzed. Particulate matter recycling, preheating of raw materials, and the use of coal and flue gas desulfurization derived gypsum contributed to emissions of Hg in the air and to accumulation in cement. Over 90% of the mercury input was emitted into the atmosphere. Mercury emission factors were 0.044-0.072 g/t clinker for the test plants. The major species emitted into the atmosphere from cement plants is oxidized mercury, accounting for 61%-91% of the total mercury in flue gas. The results of this study help improve the accuracy of the mercury emission inventory in China and provide useful information for developing mercury controls.

  10. Research on Heating Problem of Rotary Kiln Axle Tile Care%回转窑托轮轴瓦发热问题的研究

    Institute of Scientific and Technical Information of China (English)

    和春梅; 杨晓杰; 罗玉银

    2011-01-01

    The rotary kiln, as the "heart" equipment of cement production, often appears the phenomenon of tile prop shaft heat in the using process,which lead to the low efficiency of rotary kiln.This article analyzes the main causes of heating problem of the rotary kiln tile axle from the two aspects of the lubrication and load distribution condition, and proposes the appropriate preventive measures.%回转窑作为水泥生产时的"心脏"设备,在使用过程中常常出现托轮轴瓦发热的现象,这是导致回转窑工作效率降低的最直接和最普遍的问题.本文主要从润滑状态和载荷分布情况与两个方面,分析了回转窑托轮轴瓦发热的主要原因,并指出了相应的预防措施.

  11. Particulate Matter Emissions Factors for Dust from Unique Military Activities

    Science.gov (United States)

    2010-06-01

    processes, together with evaporites (including artificially added potassium sulfate) serve to cement the silicate and other particles in the soils, so...processes. A sub-microscopic veneer (desert varnish) of clay minerals, with or without iron oxides generally coats the silicates, making the...dolomite, originally inter-granular cement in undisturbed dust Backscattered Electron Image (BEI) of same particle Appendix B

  12. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-07-30

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

  13. Guidebook for Using the Tool BEST Cement: Benchmarking and Energy Savings Tool for the Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Galitsky, Christina; Price, Lynn; Zhou, Nan; Fuqiu , Zhou; Huawen, Xiong; Xuemin, Zeng; Lan, Wang

    2008-07-30

    The Benchmarking and Energy Savings Tool (BEST) Cement is a process-based tool based on commercially available efficiency technologies used anywhere in the world applicable to the cement industry. This version has been designed for use in China. No actual cement facility with every single efficiency measure included in the benchmark will likely exist; however, the benchmark sets a reasonable standard by which to compare for plants striving to be the best. The energy consumption of the benchmark facility differs due to differences in processing at a given cement facility. The tool accounts for most of these variables and allows the user to adapt the model to operational variables specific for his/her cement facility. Figure 1 shows the boundaries included in a plant modeled by BEST Cement. In order to model the benchmark, i.e., the most energy efficient cement facility, so that it represents a facility similar to the user's cement facility, the user is first required to input production variables in the input sheet (see Section 6 for more information on how to input variables). These variables allow the tool to estimate a benchmark facility that is similar to the user's cement plant, giving a better picture of the potential for that particular facility, rather than benchmarking against a generic one. The input variables required include the following: (1) the amount of raw materials used in tonnes per year (limestone, gypsum, clay minerals, iron ore, blast furnace slag, fly ash, slag from other industries, natural pozzolans, limestone powder (used post-clinker stage), municipal wastes and others); the amount of raw materials that are preblended (prehomogenized and proportioned) and crushed (in tonnes per year); (2) the amount of additives that are dried and ground (in tonnes per year); (3) the production of clinker (in tonnes per year) from each kiln by kiln type; (4) the amount of raw materials, coal and clinker that is ground by mill type (in tonnes per

  14. Emissions from carpet combustion in a pilot-scale rotary kiln: comparison with coal and particle-board combustion.

    Science.gov (United States)

    Konopa, Stephanie Lucero; Mulholland, James A; Realff, Matthew J; Lemieux, Paul M

    2008-08-01

    The use of post-consumer carpet as a potential fuel substitute in cement kilns and other high-temperature processes is being considered to address the problem of huge volumes of carpet waste and the opportunity of waste-to-energy recovery. Carpet represents a high volume waste stream, provides high energy value, and contains other recoverable materials for the production of cement. This research studied the emission characteristics of burning 0.46-kg charges of chopped nylon carpet squares, pulverized coal, and particle-board pellets in a pilot-scale natural gas-fired rotary kiln. Carpet was tested with different amounts of water added. Emissions of oxygen, carbon dioxide, nitric oxide (NO), sulfur dioxide (SO2), carbon monoxide (CO), and total hydrocarbons and temperatures were continuously monitored. It was found that carpet burned faster and more completely than coal and particle board, with a rapid volatile release that resulted in large and variable transient emission peaks. NO emissions from carpet combustion ranged from 0.06 to 0.15 g/MJ and were inversely related to CO emissions. Carpet combustion yielded higher NO emissions than coal and particle-board combustion, consistent with its higher nitrogen content. SO2 emissions were highest for coal combustion, consistent with its higher sulfur content than carpet or particle board. Adding water to carpet slowed its burn time and reduced variability in the emission transients, reducing the CO peak but increasing NO emissions. Results of this study indicate that carpet waste can be used as an effective alternative fuel, with the caveats that it might be necessary to wet carpet or chop it finely to avoid excessive transient puff emissions due to its high volatility compared with other solid fuels, and that controlled mixing of combustion air might be used to control NO emissions from nylon carpet.

  15. 7 CFR 305.28 - Kiln sterilization treatment schedule.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Kiln sterilization treatment schedule. 305.28 Section 305.28 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH... sterilization treatment schedule. T404-b-4 Dry bulb temperature( °F) Wet bulb depression( °F)...

  16. USE OF SOLAR KILN FOR THE DRYING OF SAWN WOOD

    Directory of Open Access Journals (Sweden)

    Diego Martins Stangerlin

    2010-03-01

    Full Text Available This study aimed at evaluating the use of a solar kiln for the drying of woods of Eucalyptus tereticornis, Eucalyptus saligna and Corymbia citriodora, as well as comparing such a methodology to the air seasoning practice. In order to do so, it was built a solar kiln composed basically of wood structures, roofing with a double layer of PVC, sunlight internal collector and hot air circulation systems. The efficiency of the solar kiln was compared to the air seasoning in drying time and wood quality. In the same drying schedule, each species was submitted to the two drying approaches using a load of 55 boards in each method. Results indicated that the solar kiln was more efficient in drying time, around 2 to 5 times faster and final moisture content lower than the air drying. Adequate wood quality was observed in both drying methods, and no defects such as cup or collapse were observed. Furthermore, the correct piling up and drying process provided minimization of defects such as bow. The incidence of crook, end and surface checks were not significantly distinct between solar drying and air seasoning for the three woods studied.

  17. A Research into the Phosphogypsum as Cement Set- control ling Admixture%磷石膏作水泥缓凝剂的研究

    Institute of Scientific and Technical Information of China (English)

    蓝丽红

    2000-01-01

    After phosphogypsum is washed with water or sulphuric acid, it is used as set-controlling admixture of rotary kiln cement and shaft kiln cement. The experimental result shows that, the setting characteristics and strength of cement made of phosphogypsum processed with sulphuric acid accord with GB175-92 and can meet the needs of production.%磷石膏经过水洗或酸洗后用作立窑和旋窑的水泥缓凝剂,试验结果表明,酸处理的磷石膏配制的水泥凝结性能及强度符合GB175-92,并能满足生产的需要.

  18. Charcoal kiln relicts - a favorable site for tree growth?

    Science.gov (United States)

    Buras, Allan; Hirsch, Florian; van der Maaten, Ernst; Takla, Melanie; Räbiger, Christin; Cruz Garcia, Roberto; Schneider, Anna; Raab, Alexandra; Raab, Thomas; Wilmking, Martin

    2015-04-01

    Soils with incompletely combusted organic material (aka 'black carbon') are considered fertile for plant growth. Considerable enrichment of soils with black carbon is known from Chernozems, from anthropogenic induced altering of soils like the 'Terra Preta' in South America (e.g. Glaser, 2001), and from charcoal kiln relicts. Recent studies have reported a high spatial frequency of charcoal kiln relicts in the Northeastern German lowlands (Raab et al., 2015), which today are often overgrown by forest plantations. In this context the question arises whether these sites are favorable for tree growth. Here we compare the performance of 22 Pinus sylvestris individuals - a commonly used tree species in forestry - growing on charcoal kiln relicts with 22 control trees. Growth performance (height growth and diameter growth) of the trees was determined using dendrochronological techniques, i.e. standard ring-width measurements were undertaken on each two cores per tree and tree height was measured in the field. Several other wood properties such as annual wood density, average resin content, as well as wood chemistry were analyzed. Our results indicate that trees growing on charcoal kiln relicts grow significantly less and have a significantly lower wood density in comparison with control trees. Specific chemical components such as Manganese as well as resin contents were significantly higher in kiln trees. These results highlight that tree growth on charcoal kiln relicts is actually hampered instead of enhanced. Possibly this is a combined effect of differing physical soil properties which alter soil water accessibility for plants and differing chemical soil properties which may negatively affect tree growth either if toxic limits are surpassed or if soil nutrient availability is decreased. Additional soil analyses with respect to soil texture and soil chemistry shall reveal further insight into this hypothesis. Given the frequent distribution of charcoal kiln relicts in

  19. Prevalence and Determinants of Mucous Membrane Irritations in a Community Near a Cement Factory in Zambia: A Cross Sectional Study

    OpenAIRE

    2015-01-01

    Exposure to cement dust has been associated with deleterious health effects in humans. This study investigated whether residing near a cement factory increases the risk of irritations to the mucous membranes of the eyes and respiratory system. A cross sectional study was conducted in Freedom Compound, a community bordering a cement factory in Chilanga, Zambia and a control community, Bauleni, located 18 km from the cement plant. A modified American Thoracic Society questionnaire was administe...

  20. 回转窑托轮支承力测量方法%Support force measurement method for riding wheel of rotary kiln

    Institute of Scientific and Technical Information of China (English)

    翟敏辰; 达布希拉图; 刘珍; 包晓艳

    2015-01-01

    The rotary kiln is a core equipment in cement and some industrial production. It is important whether the roller support force is balanced and reasonable or not for service lifetime and safe operation of the equipment. As the complexity of the kiln structure and working conditions,it is very difficult to measure the actual load of each riding wheel. Taking a dry cement ro⁃tary kiln with three⁃support as an example,based on the analysis of riding wheel bearing seat structure and stress characteris⁃tics,the testing scheme of riding wheel load was designed,the validation measurement was carried out. The test results show that the method is feasible though the measurement sensitivity is insufficient.%回转窑是水泥等工业生产中的核心设备,托轮支承力是否均衡合理对设备的安全运行与寿命至关重要。由于窑体结构和工作条件的复杂性,使得通过测量获取每个托轮的实际载荷具有较大难度。以三档支撑的干法水泥生产回转窑为例,在分析托轮瓦座结构和受力特点的基础上设计了托轮载荷测试方案并进行了验证性测量。试验结果表明测试灵敏度偏低,但是方法可行。

  1. Development of cleaner-burning brick kilns in Ciudad Juarez, Chihuahua, Mexico.

    Science.gov (United States)

    Bruce, Charles W; Corral, Alba Yadira; Lara, Antonio S

    2007-04-01

    The following results provide a comparison between net airborne contamination produced by the traditional form of kiln used in Northern Mexico and by those modified according to a design by Dr. Robert Marquez. What has become known as the MK style kiln was intended to significantly reduce contaminant emissions. The concept involves covering the kiln with a dome and channeling the output of an active kiln through a second, identical loaded kiln for its additional filtration of the effluents. Kilns of a pair are connected via clay brick channels. The roles are reversed after the initial kiln is refilled. Significant reductions in the particulate and gaseous emissions were achieved in the prototype system, but a connectional problem with recent kiln pairs has also limited the degree of operational success. The problem did not mask the potential of the MK kiln, as will be shown. Additional anticipated benefits to the owners of MK kilns, such as reduced operating cycles and decreased quantities of fuel, also have been verified. Key measurements made during all of the burns were of aerosol densities and buoyancies in the flues, kiln temperatures, and, on a number of occasions, chemical analyses of both aerosol and gaseous effluents. Continuous time histories of aerosol densities for most burns (of a total of -40) provide a basis for examining features and the effects of differing styles of operation with respect to burn efficiency and net contaminant masses. Covering the active kiln with a dome produces a net reduction in dry aerosol effluent mass of a factor between 5 and 10, whereas the addition of a filter kiln produces a net reduction of about a factor of 2. The use of used motor oil as a fuel further reduced aerosol contamination by -1 order of magnitude.

  2. Application of Waste Heat Recovery Technology for Lime Shaft Kiln%白灰竖窑余热回收技术应用

    Institute of Scientific and Technical Information of China (English)

    李淑荣; 张岩峰

    2014-01-01

    Cast iron finned-tube radiator was adopted in the design with suitable fume flowrate, successfully solving the problem of waste heat recovery from higher dust content and lower temperature fumes of kilns and bringing significant economic and social benefits.%设计采用铸铁翼片管散热器,合理确定烟气流速,成功解决了炉窑类含尘浓度高温度相对较低烟气的余热回收问题,经济和社会效益显著。

  3. A study on respiratory problems and pulmonary function indexes among cement industry workers in Mashhad, Iran

    OpenAIRE

    Ehsan Rafeemanesh; Ashkan Alizadeh; Lahya Afshari Saleh; Hosein Zakeri

    2015-01-01

    Background: The respiratory system is the most vulnerable system in the cement industry. This study was conducted to determine the effects of occupational exposure to cement dust on the respiratory system more thoroughly. Material and Methods: In this cross sectional study an interviewer-administered questionnaire on socio-demographic characteristics and respiratory symptoms was completed and pulmonary function tests were carried out on 100 exposed and 120 non-exposed workers at the cement fa...

  4. Asphalt cement poisoning

    Science.gov (United States)

    ... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. If hot ... found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for other purposes.

  5. Multi-Objective Optimization of Mechanical Running Conditions of Large Scale Statically Indeterminate Rotary Kiln

    Institute of Scientific and Technical Information of China (English)

    Hu Xiaoping; Xiao Yougang; Wang Guangbin

    2006-01-01

    Combined with the second rotary kiln of Alumina Factory in Great Wall Aluminum Company, the mechanics characteristics of statically indeterminate large-scale rotary kiln with variable cross-sections is analyzed. In order to adjusting the runing axis of rotary kiln, taking the force equilibrium of the rollers and the minimum of relative axis deflection as the optimization goal, the multi-objective optimization model of mechanical running conditions of kiln rotary is set up. The mechanical running conditions of the second rotary kiln after multi-objective optimization adjustment are compared with those before adjustment and after routine adjustment. It shows that multi-objective optimization adjustment can make axis as direct as possible and can distribute kiln loads equally.

  6. Process optimisation on Maerz PFR lime kilns; Maerz optimise le process de ses fours a chaux PFR

    Energy Technology Data Exchange (ETDEWEB)

    Piringer, H. [Maerz Ofenbau, Zurich (Switzerland)

    2005-09-01

    A considerable proportion of the world production of high reactive lime is manufactured in Parallel Flow Regenerative kilns (PFR kilns). For many decades their unmatched features i.e. the lowest heat consumption of all types of lime kilns has been a known fact in the industry. Over 400 PFR kilns world-wide have provided extensive operating data which resulted in essential findings concerning practical kiln operation. PFR lime kilns can now be built with capacities ranging from 100 to 850 metric tons of lime per day using limestone grain sizes from 10 to 200 mm and almost all types of fuel. (author)

  7. Static analysis of masonry kilns built with fictile tubules bricks

    Science.gov (United States)

    Olivito, Renato S.; Scuro, Carmelo; Codispoti, Rosamaria

    2016-12-01

    Industrial archeology is a branch that studies all the testimony (tangible and intangible, direct and indirect) related to the process of industrialization since its origins. This technical field is based on an interdisciplinary approach, it has the task of deepening the story, understanding the technological development made by man over the centuries. The present work focused attention on the study and analysis of a masonry kiln, built with the technique of hollow clay fictile tubules. The study, in particular, has been carried out analyzing the stress state caused by the wind on the structure. The kiln is constituted by a particular geometric configuration that develops in height due to the presence of chimney over the dome.

  8. Mössbauer Study of a Celtic Pottery-Making Kiln in Lower Bavaria

    Science.gov (United States)

    Gebhard, R.; Guggenbichler, E.; Häusler, W.; Riederer, J.; Schmotz, K.; Wagner, F. E.; Wagner, U.

    2004-06-01

    In 1995 a well preserved 3rd century BC Celtic kiln for pottery making was excavated at Schmiedorf in Lower Bavaria. The firing chamber and the flue plate of the kiln were preserved, whereas the dome was not found. We report on a study of material from this kiln by neutron activation analysis, thin-section microscopy, X-ray diffraction and Mössbauer spectroscopy, all performed with the aim to learn more about pottery-making procedures in Celtic times.

  9. Moessbauer Study of a Celtic Pottery-Making Kiln in Lower Bavaria

    Energy Technology Data Exchange (ETDEWEB)

    Gebhard, R. [Archaeologische Staatssammlung (Germany); Guggenbichler, E.; Haeusler, W. [Technische Universitaet Muenchen, Physik Department E15 (Germany); Riederer, J. [Staatliche Museen Preussischer Kulturbesitz, Rathgen-Forschungslabor (Germany); Schmotz, K. [Kreisarchaeologie Deggendorf (Germany); Wagner, F. E.; Wagner, U. [Technische Universitaet Muenchen, Physik Department E15 (Germany)

    2004-06-15

    In 1995 a well preserved 3rd century BC Celtic kiln for pottery making was excavated at Schmiedorf in Lower Bavaria. The firing chamber and the flue plate of the kiln were preserved, whereas the dome was not found. We report on a study of material from this kiln by neutron activation analysis, thin-section microscopy, X-ray diffraction and Moessbauer spectroscopy, all performed with the aim to learn more about pottery-making procedures in Celtic times.

  10. Improved charcoal production methods using the casamance kiln in Uganda

    Energy Technology Data Exchange (ETDEWEB)

    Nturanabo, F. (Makerere Univ., Kampala (Uganda), Dept. of Mechanical Engineering), e-mail: mpazi@tech.mak.ac.ug; Tumuhimbise, J. (Ministry of Energy and Mineral Development, Kampala (Uganda))

    2010-07-01

    Uganda's energy mix depicts heavy reliance on biomass for most of the country's energy needs. Woodfuel is the major source of energy for heating, cooking and lighting. According to the Uganda Energy Balance 2008, biomass resources account for 91,5 % of Uganda's net energy supply. Consumption of wood has been rising at the same rate as the country's population (3,6 % per year as of 2008). The solution to check the rampant deforestation and environmental degradation that result from over-exploitation of the forest resources lies in harvesting the wood sustainably by using more efficient methods. The purpose of this research was to promote use of the casamance kiln as an efficient and environment-friendly charcoal production method. The study aimed at establishing a simpler version of casamance that involves minimal capital investment for low-income producers to adopt easily. The results show that the casamance kiln is easy to operate, takes a shorter cycle time and produces higher quality charcoal. Its efficiency of yield was in the range of 24-28 %, compared to the traditional earth mound whose range was 12-16 %. A 20 m3 casamance kiln operating at 28 % efficiency for 30 weeks a year can save 85 tonnes of wood. (orig.)

  11. 大型多支承变刚度回转窑支承载荷分配问题%Research on supporting load distribution of large-scale rotary kiln with multi-support and variable-stiffness

    Institute of Scientific and Technical Information of China (English)

    李学军; 蒋玲莉; 刘德顺

    2005-01-01

    回转窑是冶金、水泥、耐火材料生产中的核心设备,是一种重载、大扭矩、多支点、静不定运行系统,由于其载荷和刚度分布复杂、各支承存在偏移,作用在它托轮上的支承载荷分配严重不均.本文针对回转窑载荷和刚度分布的特点,建立支承载荷求解的力学模型和线性方程组,导出支承载荷分配与支承偏差的关系式;用该方法对现场回转窑进行计算,得出该窑支承载荷分配的线性公式和一些分析结论,为生产中回转窑的状态分析、优化调控提供依据.%Kiln are the key equipment in the production of metallurgy, cement and material of fire-fast. It is the statically indeterminate system with over load, large torque and multi-support. Because of the complexity of load and stiffness distribution of the rotary kiln, the deflection of supporting center, the supporting load distribution will become seriously non-uniform. To the characters of load and stiffness distribution of the rotary kiln, the mechanical model and equation group are established, which are used to solve the variable-stiffness beam upon complex load for kiln. The relation between the supporting load distribution and deflection is derived. Accordingly, the liner formulas for calculating the support force of the support wheels fixing on the rotate kiln are obtained from the practical calculation of rotary kilns, and some useful analysis conclusions are obtained. This will provide helpful guide to condition analysis and optimization control of rotary kiln.

  12. Feasibility study of the Portland cement industry waste for the reduction of energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    Bernardo, Ana Carla de Souza Masselli; Junqueira, Mateus Augusto F. Chaib; Jorge, Ariosto Bretanha; Silva, Rogerio Jose da [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Institute of Mechanical Engineering]. E-mails: anacarlasz@unifei.edu.br; mateus_afcj@yahoo.com.br; ariosto.b.jorge@unifei.edu.br; rogeriojs@unifei.edu.br

    2008-07-01

    The Portland cement industry demand a high specific consumption of energy for the production of the clinker. The energy consumption for clinker production varies between 3000 and 5300 kJ/kg of produced clinker. The clinker is produced by blending of different raw materials in order t o achieve precise chemical proportions of lime, silica, alumina and iron in the finished product and by burning them at high temperatures. The Portland cement is a mixture of clinker, gypsum and other materials. Due to need of high temperatures, tradition ally the fuels used in the cement industry are mineral coal, fuel oil, natural gas and petroleum coke. The fuel burning in high temperature leads to the formation of the pollutant thermal NOx. The level of emissions of this pollutant is controlled by environmental law, thus the formation of pollutants in process need be controlled. Moreover, industrial waste has been used by Portland cement industries as a secondary fuel through a technique called co -processing. Materials like waste oils, plastics, waste tyres and sewage sludge are often proposed as alternative fuels for the cement industry. The residues can be introduced as secondary fuel or secondary raw material. For energy conservation in the process, mineralizers are added during the process production of the clinker. The mineralizers promote certain reactions which decrease the temperature in the kiln and improve the quality of the clinker. The adequate quantity of constituents in production process is complex, for maintain in controlled level, the quality of final product, the operational conditions of kiln, and the pollutant emissions. The purpose of the present work is to provide an analysis of an optimal production point through of the optimization technique considering, the introduction of the fuels, industrial wastes as secondary fuels, and raw materials, for the reduction of energy in the process of Portland cement production. (author)

  13. Long-term sampling of dioxin-like substances from a clinker kiln stack using alternative fuels.

    Science.gov (United States)

    Rivera-Austrui, J; Martinez, K; Marco-Almagro, L; Abalos, M; Abad, E

    2014-07-01

    The aim of this work is to characterize atmospheric emissions of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) from a cement production plant where the existing clinker production line was completely replaced by a new state-of-the-art installation. The project started in April 2008 with the installation of a long-term sampling system in the stack of the clinker kiln that used petroleum coke as fuel; PCDD/PCDF and dl-PCB emissions were then evaluated for a two year period. To carry out the second part of the study, in 2010 the sampling system was moved to the new installation in which, apart from conventional fuel, recovered derived fuel (RDF) and WWTP sludge were used as alternative fuels. For both the old and new clinker kilns, PCDD/PCDF emission values were well below the limit established by the European Waste Incineration Directive 2000/76/CE (EWID) of 100 pg I-TEQ/Nm(3); values ranged from 0.43 to 2.02 and from 0.07 to 3.31 pg I-TEQ/Nm(3), respectively. dl-PCBs accounted for approximately 25% of the WHO-TEQ toxicity. These results prove that the installation is capable of reducing PCDD/PCDF and dl-PCB emissions when alternative fuels are integrated into the process. In the case of PCDDs/PCDFs, the major contributions to total TEQ were usually from 2,3,7,8-TCDD (owing to its relative abundance) and 2,3,4,7,8-PeCDF (due to its high I-TEF of 0.5); while for dl-PCBs, the major contribution was from PCB-126. The slight shift in the congener profile between the old and new installations was characterized and a regression model was proposed for dl-PCB emissions depending on the RDF flow rate in the clinker.

  14. 基于神经网络的回转窑建模及其优化控制设计%Model of Rotary Kiln Based on Neural Network and Design of Optimization Control

    Institute of Scientific and Technical Information of China (English)

    覃新颖; 佘乾仲; 彭奎; 杨晓娜

    2012-01-01

    Calcination process of cement clinker is a complex multi - variable large - disturbances and nonlinear system which is full of mass transfer, heat transfer, physical and chemical reactions. In order to reduce energy con sumption and ensure the quality of cement clinker burning, it is necessary to explore methods superior to the tradition al PID to stabilize the temperature of rotary kiln. PID control methods based on BP nerual network can adjust the con trol parameters of PID according to the operational status of the system, and achieve a performance optimization. It has many advantages such as small overshoot, good dynamics, fast convergence rate, high controlled resolution and so on. In this paper, rotary kiln model was established by Elman neural network, and an optimize controller was de signed with the PID control methods based on BP nerual network. The results show that, after the fluctuations in the early control period, the temperature of cement rotary kiln tends to be stabilized and realize the simulation control of cement rotary kiln.%实现水泥回转窑温度稳定性控制,水泥回转窑熟料煅烧是一个涉及传质、传热和物理化学反应的复杂多变量、多扰动非线性过程.为了稳定回转窑烧成温度以提高孰料烧成质量,降低能耗,传统的控制方法,存在干扰大,稳定时间长等问题.在分析水泥回转窑工艺的基础上,采用Elman神经网络建立回转窑系统的模型,提出BP神经网络的PID控制方法,根据系统的运行状态,调节PID控制器的参数,以达到性能指标,设计了回转窑温度优化控制器,具有超调量小、动态性好、收敛速度快和控制精度高等优点.进行仿真的结果表明,回转窑烧成带温度逐渐趋于稳定,实现了对水泥回转窑的优化控制.

  15. Air emission from the co-combustion of alternative derived fuels within cement plants: Gaseous pollutants.

    Science.gov (United States)

    Richards, Glen; Agranovski, Igor E

    2015-02-01

    Cement manufacturing is a resource- and energy-intensive industry, utilizing 9% of global industrial energy use while releasing more than 5% of global carbon dioxide (CO₂) emissions. With an increasing demand of production set to double by 2050, so too will be its carbon footprint. However, Australian cement plants have great potential for energy savings and emission reductions through the substitution of combustion fuels with a proportion of alternative derived fuels (ADFs), namely, fuels derived from wastes. This paper presents the environmental emissions monitoring of 10 cement batching plants while under baseline and ADF operating conditions, and an assessment of parameters influencing combustion. The experiential runs included the varied substitution rates of seven waste streams and the monitoring of seven target pollutants. The co-combustion tests of waste oil, wood chips, wood chips and plastic, waste solvents, and shredded tires were shown to have the minimal influence when compared to baseline runs, or had significantly reduced the unit mass emission factor of pollutants. With an increasing ADF% substitution, monitoring identified there to be no subsequent emission effects and that key process parameters contributing to contaminant suppression include (1) precalciner and kiln fuel firing rate and residence time; (2) preheater and precalciner gas and material temperature; (3) rotary kiln flame temperature; (4) fuel-air ratio and percentage of excess oxygen; and (5) the rate of meal feed and rate of clinker produced.

  16. Comparative Analysis of Air Emission from Cement Plant Using TDF as Partial Substitute for Coal

    Directory of Open Access Journals (Sweden)

    Syeda Fateeha Arshed

    2014-07-01

    Full Text Available Tyre derived fuel (TDF has a potential advantage for its use as a co-fuel with coal in rotary kilns of cement plants.  In this study we analyzed the emissions of selected criteria pollutants; CO2, CO, NOx, SOx and PM to suggest suitable proportion of TDF to replace coal when different proportions of TDF and coal were used as cement kiln feed. Emissions of CO2, CO, NO, NO2, SO2 and total PM from stack and concentrations of CO, NOx, SOx and PM10 in ambient air were assessed using USEPA recommended methods. Substitution such as 85% coal and 15% TDF, 80% coal and 20% TDF, 75% coal and 25% TDF and 70% coal and 30% TDF were applied in this study. Results of the current study revealed a rise in CO and TPM stack emissions with an increase in proportions of TDF and crossed standards at 80% coal and 20% TDF. Decline in NOx emissions up-till 15% proportion of TDF was observed and remained lower than the emission of NOx at 100% coal use in spite of an increase in its concentration at each increased proportion of TDF above 15% TDF use. No significant difference (p > 0.05 in ambient air pollutant concentration with and without TDF use was observed. The study suggested 15% TDF substitution as a preferable proportion for the selected cement plant. DOI: http://dx.doi.org/10.5755/j01.erem.68.2.6471

  17. Allergies, asthma, and dust

    Science.gov (United States)

    Reactive airway disease - dust; Bronchial asthma - dust; Triggers - dust ... Things that make allergies or asthma worse are called triggers. Dust is a common trigger. When your asthma or allergies become worse due to dust, you are ...

  18. Method and apparatus for maximizing throughput of indirectly heated rotary kilns

    Energy Technology Data Exchange (ETDEWEB)

    Coates, Ralph L; Smoot, Douglas L.; Hatfield, Kent E

    2016-06-21

    An apparatus and method for achieving improved throughput capacity of indirectly heated rotary kilns used to produce pyrolysis products such as shale oils or coal oils that are susceptible to decomposition by high kiln wall temperatures is disclosed. High throughput is achieved by firing the kiln such that optimum wall temperatures are maintained beginning at the point where the materials enter the heating section of the kiln and extending to the point where the materials leave the heated section. Multiple high velocity burners are arranged such that combustion products directly impact on the area of the kiln wall covered internally by the solid material being heated. Firing rates for the burners are controlled to maintain optimum wall temperatures.

  19. Method and apparatus for maximizing throughput of indirectly heated rotary kilns

    Science.gov (United States)

    Coates, Ralph L; Smoot, L. Douglas; Hatfield, Kent E

    2012-10-30

    An apparatus and method for achieving improved throughput capacity of indirectly heated rotary kilns used to produce pyrolysis products such as shale oils or coal oils that are susceptible to decomposition by high kiln wall temperatures is disclosed. High throughput is achieved by firing the kiln such that optimum wall temperatures are maintained beginning at the point where the materials enter the heating section of the kiln and extending to the point where the materials leave the heated section. Multiple high velocity burners are arranged such that combustion products directly impact on the area of the kiln wall covered internally by the solid material being heated. Firing rates for the burners are controlled to maintain optimum wall temperatures.

  20. 回转窑焚烧炉在某县危废焚烧处理中的应用%Application of Rotary Kiln Incinerator in Hazardous Waste Incineration in One Country

    Institute of Scientific and Technical Information of China (English)

    肖燕; 李军; 伍长青

    2015-01-01

    The engineering principle and performance characteristics of rotary kiln incinerator system were analyzed from the types and scale of hazardous waste incineration,process selection,the design of rotary kiln incinerator,and the analysis of engineering example with an example of hazardous waste incineration disposal engineering in one country. The results show that the process of rotary kiln,second combustion chamber,waste heat boiler,quench tower,semi-dry reaction tower, dry acid tower, and bag-type dust collector was adopted. It controls the rotary kiln temperature about 850 ℃,the residence time of haz-ardous waste in rotary kiln around 60 minutes,the speed of rotary kiln is 0.2~1.0 r/min,the angle of rotary kiln is 2°. The tem-perature of second combustion chamber is greater than 1 100 ℃,the residence time of smoke in the combustion chamber is greater than 2 seconds. Under this condition, clinker ignition loss is less than 5%,burned removal rate is greater than 99.99%, and the flue gas emission meets GB 18484—2001.%以某县危险废物焚烧处置工程为例,从危险废物焚烧处理种类及规模、工艺选择、回转窑焚烧炉设计、工程实例分析4个方面探讨回转窑焚烧炉系统的工程原理和性能特点,结果表明:采用“回转窑+二燃室+余热锅炉+急冷塔+半干反应塔+干式脱酸塔+布袋除尘器”工艺,回转窑温度控制在850℃左右,危险废物在回转窑停留时间60 min 左右,转速0.2~1.0 r/min,倾斜角度2°;二燃室温度>1100℃,烟气在二燃室内停留时间>2 s。在此条件下,炉渣热灼减率<5%,飞灰去除率>99.99%,烟气排放满足 GB 18484—2001。

  1. System of lower cogeneration in the cement industry; Sistema de cogeneracion inferior en la industria del cemento

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Vazquez, A; Ambriz, J. J.; Fosado, A.; Cedillo, D.; Sanchez, R. [Universidad Autonoma Metropolitana-Iztapalapa (Mexico)

    1999-07-01

    In this paper present work, the design of a cogeneration system was made, taking advantage of the waste thermal flows in a cement manufacturing industry. The costs by concept of energy sources in the cement industry represent between 30 and 60% of the production costs, reason why any diminution in its consumption, will be reflected considerably in the productivity of the company. In order to determine the available capacity of waste energy and to establish the dimension of the cogeneration system it was decided to initially conduct balances of matter and energy of a cement production train. For the evaluation and numerical simulation a case study of a national plant was taken. The analysis takes only into account the rotary kiln, the pre roaster, the gas cooler or conditioner, the cooler of clinker and the separators or dust recuperators. In this study the electrical mills nor the systems that operate all over the plant have been taken in consideration. The results show that in general a high potential of co-generation exists since in some cases the heat losses can reach up to a 50% of the calorific energy input. The capacity of electrical generation by means of a steam turbine when taking advantage of a fraction (in the order of 60%) the residual heat, can be between 200 and 300 watts per kilogram of clinker produced. In conclusion, when recovering by means of appropriate heat exchangers for each one of the mentioned equipment the wasted energy and a network of heat interchange optimized by means of modern technologies an important part of the electrical energy that a cement mill uses can be generated. The method used has been very attractive and with the possibility of applying it to any cement mill and thus evaluate the potentials of energy co-generation. [Spanish] En el presente trabajo, se realizo el diseno de un sistema de cogeneracion aprovechando las corrientes termicas de desecho en una industria de fabricacion de cemento. Los costos por concepto de

  2. 预分解窑系统在稳定运行条件下的用风%Air consumption of the pre- calcining kiln system under normal running conditions

    Institute of Scientific and Technical Information of China (English)

    考宏涛; 陆雷; 李敏; 胡道和

    2001-01-01

    根据预分解窑系统煤粉燃烧的特点,结合国内几家预分解窑的实际生产情况,探讨了窑炉在稳定运行条件下的用风量及其风量平衡问题,强调指出烧成系统风、煤、料的合理匹配对系统正常运转的重要性,为指导工厂的实际操作提供了参考。%Based on the characteristics of combustion of the pulverized coal in precalciner kilns, in combination with the actual production of a few domestic cement plants with the precalcining kiln, the gas flow rate and its equilibrium between the kiln and precalciner under the steady condition were discussed. The importance of the suitable arrangement of the gas, coal and raw real used in the sintering system was emphasized. Reference to conduct the actual operation of the plants was presented.

  3. Research on rotary kiln surface heat absorption refrigeration technology%水泥回转窑筒体表面余热吸收式制冷技术研究

    Institute of Scientific and Technical Information of China (English)

    陈华东

    2014-01-01

    Cement production industry is a high energy consumption industry, and the loss rate of rotary kiln surface in whole imput en-ergy is high up to 10%. By setting heat gathering cover on rotary kiln surface, 100℃hot water can be gained. Using the hot water in lithium bromide absorption refrigeration unit, cooling capacity of 1 516 kW can be obtained. Compared with ordinary air-conditioning and electric compressor refrigeration technology, refrigeration by lithium bromide absorption refrigeration technology using rotary kiln surface waste heat can save 200,000 RMB every summer.%水泥生产是一个高耗能的行业,回转窑筒体表面的余热损失可达输入能量的10%。通过在回转窑表面布置集热罩,可得到平均温度为100℃的热水。这些热水用于溴化锂吸收式制冷机组,可以得到制冷量1516 kW,相较于普通空调和电动压缩机制冷技术,采用溴化锂吸收式制冷技术回收回转窑表面余热进行制冷每年夏天可以节省20万元左右电费。

  4. On the Measurement of Cement Clinker‘s Adherence on Basic Refractories

    Institute of Scientific and Technical Information of China (English)

    GUOZongqi; MichelRigaud

    2001-01-01

    A new sandwich test has been developed to measure the adherence of cement clinker on basic refractories to test their coatability,Statistical desings of experiment method-ology were employed for evaluations of the sandwich test.Three fractional factorial tests and one full factorial test were executed to efficiently generate data that reveal the significance of the major factors and the ruggedness to the minor factors .Its repeatability and reproducibility have been statistically confirmed to be acceptable,Evaluations on various basic bricks by the sandwich test reflect their coating performance in rotary kiln.

  5. Review: Circulation of Inorganic Elements in Combustion of Alternative Fuels in Cement Plants

    DEFF Research Database (Denmark)

    Cortada Mut, Maria del Mar; Nørskov, Linda Kaare; Jappe Frandsen, Flemming

    2015-01-01

    Cement production is an energy-intensive process, which traditionally has been dependent on fossil fuels. However, the use of alternative fuels, i.e., selected waste, biomass, and byproducts with recoverable calorific value, is constantly increasing. Combustion of these fuels is more challenging......, compared to fossil fuels, because of a lack of experience and different chemical and physical properties. When complete oxidation Of fuels in the calciner and main burner is not achieved, they burn in direct contact with the bed material of the rotary kiln, causing local reducing conditions and increasing...

  6. 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.

  7. The dissolution of natural and artificial dusts in glutamic acid

    Science.gov (United States)

    Ling, Zhang; Faqin, Dong; Xiaochun, He

    2015-06-01

    This article describes the characteristics of natural dusts, industrial dusts, and artificial dusts, such as mineral phases, chemical components, morphological observation and size. Quartz and calcite are the main phases of natural dusts and industrial dusts with high SiO2 and CaO and low K2O and Na2O in the chemical composition. The dissolution and electrochemical action of dusts in glutamic acid liquor at the simulated human body temperature (37 °C) in 32 h was investigated. The potential harm that the dust could lead to in body glutamic acid acidic environment, namely biological activity, is of great importance for revealing the human toxicological mechanism. The changes of pH values and electric conductivity of suspension of those dusts were similar, increased slowly in the first 8 h, and then the pH values increased rapidly. The total amount of dissolved ions of K, Ca, Na, and Mg was 35.4 to 429 mg/kg, particularly Ca was maximal of 20 to 334 mg/kg. The total amount of dissolved ions of Fe, Zn, Mn, Pb, and Ba was 0.18 to 5.59 mg/kg and in Al and Si was 3.0 to 21.7 mg/kg. The relative solubility order of dusts in glutamic acid is wollastonite > serpentine > sepiolite, the cement plant industrial dusts > natural dusts > power plant industrial dusts. The wollastonite and cement plant industrial dusts have the highest solubility, which also have high content of CaO; this shows that there are a poorer corrosion-resisting ability and lower bio-resistibility. Sepiolite and power plant industrial dusts have lowest solubility, which also have high content of SiO2; this shows that there are a higher corrosion-resisting ability and stronger bio-resistibility.

  8. Development of a three-dimensional CFD model for rotary lime kilns

    Energy Technology Data Exchange (ETDEWEB)

    Lixin Tao; Blom, Roger (FS Dynamics Sweden AB, Goeteborg (Sweden)); Nordgren, Daniel (Innventia, Stockholm (Sweden))

    2010-11-15

    In the calcium loop of the recovery cycle in a Kraft process of pulp and paper production, rotary lime kilns are used to convert the lime mud, mainly CaCO3, back to quick lime, CaO, for re-use in the causticizing process. The lime kilns are one of the major energy consumption devices for paper and pulp industry. Because of the rising oil price and new emission limits, the pulp mills have been forced to look for alternative fuels for their lime kilns. One interesting alternative to oil, often easily available at pulp mills, is biofuels such as sawdust and bark. However the practical kiln operation often encounters some difficulties because of the uncertainties around the biofuel impact on the lime kiln performance. A deeper understanding of the flame characteristics is required when shifting from oil to biofuels. Fortunately recent advances in modern Computational Fluid Dynamics, CFD, have provided the possibility to study and predict the detailed flame characteristics regarding the lime kiln performance. In this project a three-dimensional CFD model for rotary lime kilns has been developed. To simulate a rotary lime kiln the developed CFD model integrates the three essential sub-models, i.e. the freeboard hot flow model, the lime bed model and the rotating refractory wall model and it is developed based on the modern CFD package: FLUENT which is commercially available on the market. The numerical simulations using the developed CFD model have been performed for three selected kiln operations fired with three different fuel mixtures. The predicted results from the CFD modelling are presented and discussed in order to compare the impacts on the kiln performance due to the different firing conditions. During the development, the lime kiln at the Soedra Cell Moensteraas mill has been used as reference kiln. To validate the CFD model, in-plant measurements were carried out in the Moensteraas lime kiln during an experiment campaign. The results obtained from the

  9. Effect of brick kiln emissions on commonly used vegetables of Kashmir Valley.

    Science.gov (United States)

    Skinder, Bhat M; Sheikh, Afeefa Q; Pandit, Ashok K; Ganai, Bashir A; Kuchy, Aashiq H

    2015-11-01

    To study the impact of brick kiln emissions on plant growth and productivity, a study was conducted on various biochemical parameters of three main vegetables Brassica oleracea L., Phaseolus vulgaris L., and Solanum melongena L. cultivated in the vicinity of the brick kiln area of the Panzan village of district Budgam (J&K). Plants in the vicinity of brick kilns are direct recipients of emissions and therefore important materials for assessing potential effects of kiln pollutants. The biochemical values of all the three vegetables of the brick kiln site when compared to the control site are significantly (P ≤ 0.05) different. The findings of the present work depict that the brick kilns are the prime reason for the deterioration of important consumable vegetables, which could lead to chaos in the food security of the area in concern besides a threat to local people in terms of health if proper pollution control devices or the replacement of brick kilns are not put in place with new technology.

  10. Mathematic simulation of heat transfer and operating optimization in alumina rotary kiln

    Institute of Scientific and Technical Information of China (English)

    易正明; 肖慧; 宋佳霖; 马光柏; 周孑民

    2013-01-01

    Based on the analysis of material motion in the axial direction, heat transfer and mass transport processes in a rotary kiln, and combining with pulverized coal combustion, material pyrogenation, cooling of furnace wall finally, and heat transfer and mass transport equations, the combined heat transfer mathematical model for alumina rotary kiln was built up. According to the in-site real operation parameters, the heat transfer mathematical model was solved numerically for an alumina rotary kiln to predict the temperature profiles of gas and material in the axial direction. The results show that as the excess air coefficient reduces from 1.38 to 1.20, the temperature of the sintering zone increases and the length decreases. However, as the excess air coefficient reduces from 1.20 to 1.10, the temperature of the sintering zone decreases and the length increases. When the mixed coal amount at the end of kiln is reduced from 68.6 kg/t to 62.0 kg/t and the burned coal amount at the head of kiln correspondingly increases from 155.3 kg/t to 161.9 kg/t, the sintering zone temperature increases and the length reduces. The suitable excess air coefficient and mixed coal amount at the end of kiln are recommended for the rotary kiln operation optimization.

  11. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-01-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

  12. Impact of Alkaline Dust Pollution on Soil Microbial Biomass Carbon

    OpenAIRE

    Kara, Ömer; Bolat, İlyas

    2007-01-01

    The effect of alkaline dust pollution emitted from Bartın cement plant on the soil microbial biomass carbon was investigated using the chloroform fumigation-extraction (CFE) method. Microbial biomass C (Cmic) values ranged from 157.82 to 1201.51 µg g-1 soils in the polluted area and from 726.70 to 1529.14 µg g-1 soils in the control area. Soils polluted with alkaline cement dust resulted in significant reductions in Cmic levels compared to control soils. Microbial biomass C correlated negativ...

  13. Impact of Alkaline Dust Pollution on Soil Microbial Biomass Carbon

    OpenAIRE

    KARA, Ömer; Bolat, İlyas

    2014-01-01

    The effect of alkaline dust pollution emitted from Bartın cement plant on the soil microbial biomass carbon was investigated using the chloroform fumigation-extraction (CFE) method. Microbial biomass C (Cmic) values ranged from 157.82 to 1201.51 µg g-1 soils in the polluted area and from 726.70 to 1529.14 µg g-1 soils in the control area. Soils polluted with alkaline cement dust resulted in significant reductions in Cmic levels compared to control soils. Microbial biomass C correlated negativ...

  14. Coal desulfurization in a rotary kiln combustor. Final report, March 15, 1990--July 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, J.T. Jr.

    1992-09-11

    The purpose of this project was to demonstrate the combustion of coal and coal wastes in a rotary kiln reactor with limestone addition for sulfur control. The rationale for the project was the perception that rotary systems could bring several advantages to combustion of these fuels, and may thus offer an alternative to fluid-bed boilers. Towards this end, an existing wood pyrolysis kiln (the Humphrey Charcoal kiln) was to be suitably refurbished and retrofitted with a specially designed version of a patented air distributor provided by Universal Energy, Inc. (UEI). As the project progressed beyond the initial stages, a number of issues were raised regarding the feasibility and the possible advantages of burning coals in a rotary kiln combustor and, in particular, the suitability of the Humphrey Charcoal kiln as a combustor. Instead, an opportunity arose to conduct combustion tests in the PEDCO Rotary Cascading-Bed Boiler (RCBB) commercial demonstration unit at the North American Rayon CO. (NARCO) in Elizabethton, TN. The tests focused on anthracite culm and had two objectives: (a) determine the feasibility of burning anthracite culms in a rotary kiln boiler and (b) obtain input for any further work involving the Humphrey Charcoal kiln combustor. A number of tests were conducted at the PEDCO unit. The last one was conducted on anthracite culm procured directly from the feed bin of a commercial circulating fluid-bed boiler. The results were disappointing; it was difficult to maintain sustained combustion even when large quantities of supplemental fuel were used. Combustion efficiency was poor, around 60 percent. The results suggest that the rotary kiln boiler, as designed, is ill-suited with respect to low-grade, hard to burn solid fuels, such as anthracite culm. Indeed, data from combustion of bituminous coal in the PEDCO unit suggest that with respect to coal in general, the rotary kiln boiler appears inferior to the circulating fluid bed boiler.

  15. Integrated Utilization of Sewage Sludge and Coal Gangue for Cement Clinker Products: Promoting Tricalcium Silicate Formation and Trace Elements Immobilization

    Directory of Open Access Journals (Sweden)

    Zhenzhou Yang

    2016-04-01

    Full Text Available The present study firstly proposed a method of integrated utilization of sewage sludge (SS and coal gangue (CG, two waste products, for cement clinker products with the aim of heat recovery and environment protection. The results demonstrated that the incremental amounts of SS and CG addition was favorable for the formation of tricalcium silicate (C3S during the calcinations, but excess amount of SS addition could cause the impediment effect on C3S formation. Furthermore, it was also observed that the C3S polymorphs showed the transition from rhombohedral to monoclinic structure as SS addition was increased to 15 wt %. During the calcinations, most of trace elements could be immobilized especially Zn and cannot be easily leached out. Given the encouraging results in the present study, the co-process of sewage sludge and coal gangue in the cement kiln can be expected with a higher quality of cement products and minimum pollution to the environment.

  16. Simulation and Analysis of Cement Clinker Subsection Firing%水泥熟料分段烧成模拟分析

    Institute of Scientific and Technical Information of China (English)

    封培然; 邢文杰; 齐砚勇

    2011-01-01

    By establishing the calculation of the mathematical model of NSP cement rotary kiln burning zone temperature ( BZT), this paper computed two types of different cement kiln BZT, analyzed two types of different kiln temperature distribution, then put forward the idealized burn clinker piecewise model. The study shows that short kiln in transitional zone has ordinary kiln type temperature gradient approximately 8 times, but in the burning zone both almost have no temperature change and subsection firing still have 15℃ heats up. Therefore subsection firing a has good clinker reaction temperature environment, which is beneficial to improving the quality of clinker.%通过建立新型干法水泥回转窑烧成带温度计算的数学模型,计算出两种不同水泥窑型的烧成带温度,分析了两种不同窑型的温度分布,进而提出熟料分段烧成的理想化模型。研究发现:短窑在过渡带具有普通窑型约8倍的温度梯度,但是在烧成带两者几乎没有温度变化,而分段烧成依然有15℃的升温,因此分段烧成具有良好的熟料反应温度环境,有利于熟料质量的提高。

  17. Ceiling (attic) dust: a "museum" of contamination and potential hazard.

    Science.gov (United States)

    Davis, Jeffrey J; Gulson, Brian L

    2005-10-01

    Ceiling or attic dusts provide an indirect measure of air pollution integrated over varying time periods. We undertook an investigation into the particle-size distributions and sources and exposure pathways of metals in ceiling dusts from 38 houses in the city of Sydney, Australia. The houses ranged in age from 4 to 106 years and were grouped into three settings: industrial, semi-industrial, and non-industrial. The main roof types were terracotta tile (n=23), cement tile (n=8), and corrugated iron (n=4), with two slate and one asbestos. Soils and rocks from the Sydney area were also analyzed to provide "background" values and allow the estimation of enrichment factors. The bulk of the dusts contained particles derived from soil of crustal origin and organic plant material, with an anthropogenic component estimated at up to 25%. Particle sizes from selected dust samples showed a bimodal distribution, and the volumes of fine dusts were 50% terracotta tile, cement, and iron, median regression analyses showed that there were no significant effects with respect to age. Median regression analyses for terracotta tile, cement tile, and corrugated iron roofs showed a "roof" effect for Cu and V. Significant correlations (P0.03) were observed between most of the metals As-Cd-Cu-Pb-Sb-Zn, especially from the industrial settings. Pathways of dust exposure in this study are classified as being passive or active based upon the probable route of dust infiltration. Ceiling dusts pose a probable health hazard if the dust is disturbed and allowed to plume within the living areas of a dwelling, thereby exposing the occupants, especially children, to elevated levels of metals and fine particulates. Modeling shows that exposure to the elevated levels of Pb in dust could give rise to blood lead concentrations exceeding current guidelines for the industrial and semi-industrial areas.

  18. Tympanoplasty with ionomeric cement

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    with isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those...... of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy...

  19. Cement and concrete

    Science.gov (United States)

    Corley, Gene; Haskin, Larry A.

    1992-01-01

    To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

  20. Review: Circulation of Inorganic Elements in Combustion of Alternative Fuels in Cement Plants

    DEFF Research Database (Denmark)

    Cortada Mut, Maria del Mar; Nørskov, Linda Kaare; Jappe Frandsen, Flemming;

    2015-01-01

    Cement production is an energy-intensive process, which traditionally has been dependent on fossil fuels. However, the use of alternative fuels, i.e., selected waste, biomass, and byproducts with recoverable calorific value, is constantly increasing. Combustion of these fuels is more challenging......, compared to fossil fuels, because of a lack of experience and different chemical and physical properties. When complete oxidation Of fuels in the calciner and main burner is not achieved, they burn in direct contact with the bed material of the rotary kiln, causing local reducing conditions and increasing...... the internal circulation of S, Cl, Na, and K. Compounds containing these elements, such as alkali salts, evaporate when exposed to high temperatures and subsequently condense in colder parts of the plant. The transformation of the volatile inorganic species at different locations in the cement plant...

  1. Interaction between pollutants produced in sewage sludge combustion and cement raw material.

    Science.gov (United States)

    Gálvez, Araceli; Conesa, Juan A; Martín-Gullón, Ignacio; Font, Rafael

    2007-09-01

    Nowadays the use of waste as secondary fuel in clinker kilns is an extensive practice, but the interaction between cement raw material (CRM) and the combustion gases of the fuels has not been extensively studied. Because of that, in this work the effect of the interaction of exhaust from the combustion of sewage sludge and CRM has been studied in a laboratory furnace. The experiments were performed at 300 degrees C, close to the temperature at the cyclones in a cement industry. The behavior of volatile compounds, polycyclic aromatic compounds (PAH) and polychloro dibenzo-p-dioxin and polychloro dibenzofurans (PCCD/F) were analysed in the presence or absence of CRM. The results obtained show that the presence of CRM at the outlet of the combustion gases is beneficial for the decrease of pollutant emissions.

  2. POZZOLAN AND CEMENTS WITH POZZOLAN

    OpenAIRE

    Hasan KAPLAN; Hanifi BİNİCİ

    1995-01-01

    Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, ce...

  3. Detection of hidden pre-industrial charcoal kilns by high-resolution LIDAR

    Science.gov (United States)

    Raab, Thomas; Raab, Alexandra; Nicolay, Alexander; Takla, Melanie; Rösler, Horst; Bönisch, Eberhard

    2013-04-01

    Over the last decade, systematic archaeological excavations in the open-cast mine Jänschwalde (Brandenburg, Germany) have revealed one of the largest, archaeologically excavated pre-industrial charcoal production area in Central Europe. Many of the charcoal kiln relics are easy to detect by survey as they lie close to the surface and charcoal pieces hint on their existence. In the excavations the remains of the charcoal kilns are distinct, black circles in the light-coloured sands. To date, in the former Königlich-Taubendorfer Forst c. 800 remains of charcoal hearths have been excavated and documented by archaeologists in an area of about 20 km2. Further c. 300 charcoal hearths are prospected by survey. Unfortunately, the spatial information about the charcoal kiln sites in Lower Lusatia (and elsewhere) is incomplete since we only have data from the archaeological excavation and prospection in the directly affected mining district. To fill this gap, we decided to test the applicability of Airborne Laser Scanning (ALS) data for charcoal kiln prospection. The particularly improved quality of the recent high-resolution light detection and ranging (LIDAR) data enabled the computer-aided detection of charcoal kilns and their evaluation using a geographical information system (GIS). Following data processing, the charcoal kilns are visible as buttons-like shapes in the shaded-relief maps (SRM). The characteristic shapes arise because the kiln plates are some centimetres to decimetres higher than the ditches around them. Numerous ground checks confirmed the applicability of the prospection by ALS data. But, we also assume that c. 10% of the charcoal kilns remain unidentified. A 26.6 km2 study area in the Tauerscher Forst, a forest about 10 km northwest of the open-cast mine Jänschwalde, was selected for prospection using a 1 m resolution ALS data set from the year 2011. Today, the area is forested with pine, and no archaeological excavation has been carried out so far

  4. Archaeological calibration of remagnetized volcanic rocks from pottery firing kilns in Cuentepec, Morelos, Mexico

    OpenAIRE

    L. M. Alva-Valdivia; J. A. González-Rangel; A. M. Soler-Arechalde; S. L. López-Varela; H. López-Loera

    2006-01-01

    Ethnoarchaeological research at the site of Cuentepec, Mexico includes experimental pottery dating in which social knowledge is obtained from archaeometric techniques. At Cuentepec, open kilns are used for firing pottery. Samples from volcanic rocks in the kilns were taken to verify the reliability of the magnetic direction in these rocks as compared with data from Teoloyucan Geomagnetic Observatory, near Mexico City. In the laboratory, forty-seven cores from eight hand oriented rock samples ...

  5. Do cement nanoparticles exist in space ?

    CERN Document Server

    Bilalbegovic, G; Mohacek-Grosev, V

    2014-01-01

    The calcium-silicate-hydrate is used to model properties of cement on Earth. We study cementitious nanoparticles and propose these structures as components of cosmic dust grains. Quantum density functional theory methods are applied for the calculation of infrared spectra of Ca4Si4O14H4, Ca6Si3O13H2, and Ca12Si6O26H4 clusters. We find bands distributed over the near, mid and far-infrared region. A specific calcium-silicate-hydrate spectral feature at 14 microns, together with the bands at 10 and 18 microns which exist for other silicates as well, could be used for a detection of cosmic cement. We compare calculated bands with the 14 microns features in the spectra of HD 45677, HD 44179, and IRC+10420 which were observed by Infrared Space Observatory and classified as remaining. High abundance of oxygen atoms in cementitious nanoparticles could partially explain observed depletion of this element from the interstellar medium into dust grains.

  6. Hydrogen fluoride damage to vegetation from peri-urban brick kilns in Asia: a growing but unrecognised problem?

    Science.gov (United States)

    Ahmad, Muhammad Nauman; van den Berg, Leon J L; Shah, Hamid Ullah; Masood, Tariq; Büker, Patrick; Emberson, Lisa; Ashmore, Mike

    2012-03-01

    The rapid urbanisation of many cities in south and south-east Asia has increased the demand for bricks, which are typically supplied from brick kilns in peri-urban areas. We report visible foliar damage to mango, apricot and plum trees in the vicinity of traditional Bull's Trench brick kilns in Peshawar, Pakistan. Visible injury symptoms, hydrogen fluoride concentrations in air, and foliar fluoride concentrations were all greater in the vicinity of brick kilns than at more distant sites, indicating that fluoride emissions from brick kilns were the main cause of damage. Interviews with local farmers established the significant impact of this damage on their livelihoods. Since poorly regulated brick kilns are often found close to important peri-urban agricultural areas, we suggest that this may be a growing but unrecognised environmental problem in regions of Asia where emission control in brick kilns has not been improved.

  7. Evaluation of the incorporation ratio of ZnO, PbO and CdO into cement clinker.

    Science.gov (United States)

    Barros, A M; Tenório, J A S; Espinosa, D C R

    2004-08-09

    Zinc, lead, and cadmium are minor elements that might be brought by wastes to the cement kilns. This work studies the incorporation ratio of ZnO, PbO, and CdO when they are added to the clinker raw material. The cement raw material used in this work was prepared by mixing pure compounds, this choice was made to avoid the effect of other elements and provide a better understanding of the behavior of these metals during the clinkering process. The samples contained additions of 0.05, 0.10, 0.30, 0.50, 0.80 and 1.00 wt.% of a specific oxide (ZnO, PbO, or CdO) to the clinker raw-meal. The chlorine influence in the ZnO incorporation ratio was also evaluated. A device to simulate the thermal cycle imposed on the charge during the clinker production was used to evaluate the incorporation ratio of these oxides as well as thermogravimetric tests. The products of the tests in the simulator device were submitted to X-ray fluorescence chemical analysis or energy disperse scanning (EDS) microprobe analysis. The results led to the conclusions that the evaporation of Zn in cements kilns is due to the chlorine content and the Pb and Cd incorporation ratio stands around 50 wt.%.

  8. Study on the property of the production for Fengdongyan kiln in Early Ming dynasty by INAA and EDXRF

    Energy Technology Data Exchange (ETDEWEB)

    Li, L. [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China); Huang, Y.; Sun, H.Y. [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China); University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049 (China); Yan, L.T.; Feng, S.L.; Xu, Q. [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China); Feng, X.Q., E-mail: fengxq@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China)

    2016-08-15

    A lot of official wares carved “Guan” or the dragon patterns were excavated on the strata of Ming dynasty of the Fengdongyan kiln site at Dayao County. The imperial porcelain was fired in Hongwu and Yongle eras. However, the emergence of this imperial porcelain has triggered academic debate about the property of Fengdongyan kiln in the Early Ming dynasty. Based on the differences of the official kiln management, some scholars have determined that the property of the production for this kiln was the civilian kiln. According to the historical textural records and typology, others preliminary confirmed that Fengdongyan kiln was the official kiln. In this paper, the elemental compositions of body and glaze in imperial and civilian porcelain are study by INAA and EDXRF for determining the property of the production for this kiln in Early Ming dynasty. After the processing of experimental data by geochemical analysis and principal component analysis, the result show that the raw materials for making body and glaze in imperial porcelain are similar with those of the civilian porcelain and the degrees of elutriation for body can be slightly different in HW-M period of Ming dynasty. The analytical results support the view that the Fengdongyan kiln is civilian not official.

  9. Study on the property of the production for Fengdongyan kiln in Early Ming dynasty by INAA and EDXRF

    Science.gov (United States)

    Li, L.; Huang, Y.; Sun, H. Y.; Yan, L. T.; Feng, S. L.; Xu, Q.; Feng, X. Q.

    2016-08-01

    A lot of official wares carved "Guan" or the dragon patterns were excavated on the strata of Ming dynasty of the Fengdongyan kiln site at Dayao County. The imperial porcelain was fired in Hongwu and Yongle eras. However, the emergence of this imperial porcelain has triggered academic debate about the property of Fengdongyan kiln in the Early Ming dynasty. Based on the differences of the official kiln management, some scholars have determined that the property of the production for this kiln was the civilian kiln. According to the historical textural records and typology, others preliminary confirmed that Fengdongyan kiln was the official kiln. In this paper, the elemental compositions of body and glaze in imperial and civilian porcelain are study by INAA and EDXRF for determining the property of the production for this kiln in Early Ming dynasty. After the processing of experimental data by geochemical analysis and principal component analysis, the result show that the raw materials for making body and glaze in imperial porcelain are similar with those of the civilian porcelain and the degrees of elutriation for body can be slightly different in HW-M period of Ming dynasty. The analytical results support the view that the Fengdongyan kiln is civilian not official.

  10. The Influence of the Supporting Wheel Deflection of Large-scale Rotary Kiln on Maximum Contact Stress

    Institute of Scientific and Technical Information of China (English)

    Li Xuejun; Qiu Weiliang; Yuan Yincai; Li Ping

    2006-01-01

    The relation between the maximum contact stress ratio and deflection angle is derived from Hertz contact theory when the deflection of rotary kiln supporting wheel happens. According to the analysis of practical example, the maximum contact stress ratio within the deflection range of rotary kiln supporting wheel is listed. The contact stress will increase largely when rotary kiln supporting wheel deflects with little angle,which probably will result in accidents correlating to safety. This will provide theory conference for the design,the operating condition analysis and adjusting of the rotary kiln.

  11. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  12. CO₂ capture from cement plants using oxyfired precalcination and/or calcium looping.

    Science.gov (United States)

    Rodríguez, Nuria; Murillo, Ramón; Abanades, J Carlos

    2012-02-21

    This paper compares two alternatives to capture CO(2) from cement plants: the first is designed to exploit the material and energy synergies with calcium looping technologies, CaL, and the second implements an oxyfired circulating fluidized bed precalcination step. The necessary mass and heat integration balances for these two options are solved and compared with a common reference cement plant and a cost analysis exercise is carried out. The CaL process applied to the flue gases of a clinker kiln oven is substantially identical to those proposed for similar applications to power plants flue gases. It translates into avoided cost of of 23 $/tCO(2) capturing up to 99% of the total CO(2) emitted in the plant. The avoided cost of an equivalent system with an oxyfired CFBC precalcination only, goes down to 16 $/tCO(2) but only captures 89% of the CO(2) emitted in the plant. Both cases reveal that the application of CaL or oxyfired CFBC for precalcination of CaCO(3) in a cement plant, at scales in the order of 50 MWth (referred to the oxyfired CFB calciner) is an important early opportunity for the development of CaL processes in large scale industrial applications as well as for the development of zero emissions cement plants.

  13. Development and comparison of neural network based soft sensors for online estimation of cement clinker quality.

    Science.gov (United States)

    Pani, Ajaya Kumar; Vadlamudi, Vamsi Krishna; Mohanta, Hare Krishna

    2013-01-01

    The online estimation of process outputs mostly related to quality, as opposed to their belated measurement by means of hardware measuring devices and laboratory analysis, represents the most valuable feature of soft sensors. As of now there have been very few attempts for soft sensing of cement clinker quality which is mostly done by offline laboratory analysis resulting at times in low quality clinker. In the present work three different neural network based soft sensors have been developed for online estimation of cement clinker properties. Different input and output data for a rotary cement kiln were collected from a cement plant producing 10,000 tons of clinker per day. The raw data were pre-processed to remove the outliers and the resulting missing data were imputed. The processed data were then used to develop a back propagation neural network model, a radial basis network model and a regression network model to estimate the clinker quality online. A comparison of the estimation capabilities of the three models has been done by simulation of the developed models. It was observed that radial basis network model produced better estimation capabilities than the back propagation and regression network models.

  14. 民窑之辩——石湾窑文化解析%Defence of Folk Kiln: Interpretation of Shiwan Kiln Culture

    Institute of Scientific and Technical Information of China (English)

    周彝馨; 吕唐军

    2013-01-01

    Shiwan kiln,a renowned folk kiln in China,had suffered negligence and misunderstanding in Chinese ceramic history and its representative position as "China Pottery producer" was belittled at the same time.Shiwan pottery traces back to the Neolithic age and reached the peak in Ming and Qing Dynasties.Culturally,Shiwan kiln has nine characteristics which can be summarized as follows:having a long history and extensive influence; fostering strengths and circumventing weakness; exploring original ways; assimilating the quintessence and discarding dregs; excelling at imitation and creation; deriving from life but going beyond life; endowed excellence by magic and rendered elegance by simplicity; poetic expression in treasure of art; embodying the character of Lingnan culture and the local feature of Guangdong region; masters coming forth continuously,carrying its heritage endlessly forward; skilled at craft but unconcerned about theory.The difference between official kiln and folk kiln lies in taste rather than art.Official kiln caters exclusively to the taste of the ruling class while the folk kiln aims to provide the pleasure of life to be enjoyed by common people.Simplicity makes pottery while delicateness makes porcelain.Therefore,a comparison is unable to be made between them.Shiwan kiln stands out from the famous kilns in China.The articles,shaped with common pottery clay,exceed the achievement of numerous famed kilns.They reflect Lingnan culture and succeed in pushing Chinese pottery to a summit.%石湾窑为中国著名民窑,但在中国陶瓷史上被忽略与误解,其作为“中国陶”代表的地位亦同时被贬低.石湾陶器起源于新石器时代,明清以来代表了广窑的最高水平.石湾窑的文化特点可总结为九点:源远流长,影响广泛;扬长避短,另辟蹊径;兼收并蓄,擅仿擅创;源于生活,高于生活;妙趣天成,大巧若拙;诗意表现,艺之大成;岭南风骨,广府特色;名家辈出,代代相

  15. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  16. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  17. Gas phase dispersion in a small rotary kiln

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, B.B.

    1981-07-01

    A study was made of nonideal flow of gas in a rotary kiln reactor. A rotating tube 0.165 m in diameter by 2.17 m long, with internal lifting flights, was operated at room temperature. Rotational speeds from 2.0 to 7.0 rpm, air flow rates from 0.351 to 4.178 m/sup 3//h, and solid contents of 0.0, 5.1, and 15.3% of tube volume were studied. Residence time distribution of the gas was measured by means of the pulse injection technique using a helium tracer. A model was developed based on dispersive flow that exchanges with a deadwater region. Two parameters, a dispersion number describing bulk gas flow and an interchange factor describing exchange between the flow region and the gas trapped in the solids bed, were sufficient to correlate the data, but these parameters are sensitive to experimental error. The model is applicable to analysis of other flow systems, such as packed beds.

  18. Cement Mason's Curriculum. Instructional Units.

    Science.gov (United States)

    Hendirx, Laborn J.; Patton, Bob

    To assist cement mason instructors in providing comprehensive instruction to their students, this curriculum guide treats both the skills and information necessary for cement masons in commercial and industrial construction. Ten sections are included, as follow: related information, covering orientation, safety, the history of cement, and applying…

  19. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Floyd, III, William C.; Spadaccini, Christopher M.; Vericella, John J.; Cowan, Kenneth Michael

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  20. Cementing a wellbore using cementing material encapsulated in a shell

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  1. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  2. Cement og politik

    DEFF Research Database (Denmark)

    Lund, Joachim

    2012-01-01

    as well as in the public sphere. Most of the extensive job creating measures he carried out as a minister for public works necessarily involved the use of great amounts of cement – the primary produce of F.L. Smidth & Co. Gunnar Larsen thus became an easy target for Communist propaganda, picturing him...... of the Soviet Union (including an F.L. Smidth & Co. cement plant in former Estonia). He spent the last 15 months of the occupation in Sweden and was arrested after having returned to Copenhagen in May, 1945. Although a Copenhagen city court prison sentence for economic collaboration was reversed, he had...

  3. Lung function reduction and chronic respiratory symptoms among workers in the cement industry: a follow up study

    Directory of Open Access Journals (Sweden)

    Zeleke Zeyede K

    2011-11-01

    Full Text Available Abstract Background There are only a few follow-up studies of respiratory function among cement workers. The main aims of this study were to measure total dust exposure, to examine chronic respiratory symptoms and changes in lung function among cement factory workers and controls that were followed for one year. Methods The study was conducted in two cement factories in Ethiopia. Totally, 262 personal measurements of total dust among 105 randomly selected workers were performed. Samples of total dust were collected on 37-mm cellulose acetate filters placed in closed faced Millipore-cassettes. Totally 127 workers; 56 cleaners, 44 cement production workers and 27 controls were randomly selected from two factories and examined for lung function and interviewed for chronic respiratory symptoms in 2009. Of these, 91 workers; 38 cement cleaners (mean age 32 years, 33 cement production workers (36 years and 20 controls (38 years were examined with the same measurements in 2010. Results Total geometric mean dust exposure among cleaners was 432 mg/m3. The fraction of samples exceeding the Threshold Limit Value (TLV of 10 mg/m3 for the cleaners varied from 84-97% in the four departments. The levels were considerably lower among the production workers (GM = 8.2 mg/m3, but still 48% exceeded 10 mg/m3. The prevalence of all the chronic respiratory symptoms among both cleaners and production workers was significantly higher than among the controls. Forced Expiratory Volume in one second (FEV1 and FEV1/Forced Vital Capacity (FEV1/FVC were significantly reduced from 2009 to 2010 among the cleaners (p Conclusions The high prevalence of chronic respiratory symptoms and reduction in lung function is probably associated with high cement dust exposure. Preventive measures are needed to reduce the dust exposure.

  4. Novorossiysk agglomeration landscapes and cement production: geochemical impact assessment

    Science.gov (United States)

    Alekseenko, A. V.; Pashkevich, M. A.

    2016-09-01

    The article deals with assessing the environmental impact of marl mining and cement production in Novorossiysk city (Krasnodar krai, Russia). The existing methods of studying the environmental effects caused by the cement industry have been reviewed. Soil and aquatic vegetation sampling has been carried out and the gross concentration of metals in the samples has been defined. The research has been conducted in the certified and accredited laboratory using emission spectral analysis. The external control has been carried out via X-ray fluorescence analysis. Based on the collected data, main chemical pollutants in soil cover and water area near the cement plant have been identified. The contaminants released by urban enterprises and motor vehicle emissions, as well as fugitive dust from dumps and the cement factory, lead to multi-element lithogeochemical anomaly at geochemical barriers in soils. Accumulation of pollutants in soil depends on the type of land use and the area relief. The most contaminated aquatic landscapes have been identified in the inner bay. According to this information, the technical proposals can be prepared for environmental safety management in strongly polluted city areas, as well as for the reclamation design in the areas currently experiencing the negative impact of cement production.

  5. The Development of the Clay Tobacco Pipe Kiln in the British Isles

    Directory of Open Access Journals (Sweden)

    Allan Peacey

    1996-09-01

    Full Text Available In 1982 Allan Peacey published a study in the form of a synthesis of two chronologically separated kilns used in the production of clay tobacco pipes (Peacey 1982, 3-17. The aims of the present work are: ◦to improve upon this framework ◦to establish how these type of structures fit into the broader picture; to fill the gaps, before, between and after these cameo views ◦to improve understanding of the technology employed and see the roots from which such technology developed. The primary objective is to catalogue all relevant material know to exist in museum and private collections. It is hoped that by this means an understanding of the varied physical characteristics will lead to the establishment of object or function categories around which reports may be structured. Contemporary source documents are also examined to shed further light upon the likely function of the archaeological material. Among the results achieved are the compilation of an extensive catalogue of material associated with tobacco pipe kilns; the establishment of type series for pipe kiln furniture and furniture supplements; a proposed development sequence for pipe kiln muffles; a pattern of consistency in kiln design throughout the study area, and details of the methods used for stem tipping. Readers will be able to view the archaeological evidence as distribution maps, and will be able to explore other aspects of the data through the timeline and site catalogues.

  6. CFD modeling using PDF approach for investigating the flame length in rotary kilns

    Science.gov (United States)

    Elattar, H. F.; Specht, E.; Fouda, A.; Bin-Mahfouz, Abdullah S.

    2016-02-01

    Numerical simulations using computational fluid dynamics (CFD) are performed to investigate the flame length characteristics in rotary kilns using probability density function (PDF) approach. A commercial CFD package (ANSYS-Fluent) is employed for this objective. A 2-D axisymmetric model is applied to study the effect of both operating and geometric parameters of rotary kiln on the characteristics of the flame length. Three types of gaseous fuel are used in the present work; methane (CH4), carbon monoxide (CO) and biogas (50 % CH4 + 50 % CO2). Preliminary comparison study of 2-D modeling outputs of free jet flames with available experimental data is carried out to choose and validate the proper turbulence model for the present numerical simulations. The results showed that the excess air number, diameter of kiln air entrance, radiation modeling consideration and fuel type have remarkable effects on the flame length characteristics. Numerical correlations for the rotary kiln flame length are presented in terms of the studied kiln operating and geometric parameters within acceptable error.

  7. CFD modeling using PDF approach for investigating the flame length in rotary kilns

    Science.gov (United States)

    Elattar, H. F.; Specht, E.; Fouda, A.; Bin-Mahfouz, Abdullah S.

    2016-12-01

    Numerical simulations using computational fluid dynamics (CFD) are performed to investigate the flame length characteristics in rotary kilns using probability density function (PDF) approach. A commercial CFD package (ANSYS-Fluent) is employed for this objective. A 2-D axisymmetric model is applied to study the effect of both operating and geometric parameters of rotary kiln on the characteristics of the flame length. Three types of gaseous fuel are used in the present work; methane (CH4), carbon monoxide (CO) and biogas (50 % CH4 + 50 % CO2). Preliminary comparison study of 2-D modeling outputs of free jet flames with available experimental data is carried out to choose and validate the proper turbulence model for the present numerical simulations. The results showed that the excess air number, diameter of kiln air entrance, radiation modeling consideration and fuel type have remarkable effects on the flame length characteristics. Numerical correlations for the rotary kiln flame length are presented in terms of the studied kiln operating and geometric parameters within acceptable error.

  8. German Cement Industry's voluntary efforts on the issue of climate change : a success story

    Energy Technology Data Exchange (ETDEWEB)

    Hoenig, V.; Schneider, M. [German Cement Industry (Germany)

    2001-07-01

    In 1995, the cement industry in Germany stated that it would reduce energy consumption by 20 per cent between 1987 and 2005. In 2000, this commitment was adapted to international agreements such as the Kyoto Protocol. The voluntary agreement now includes a reduction of the specific energy-related carbon dioxide emissions from 1990 to 2008/12 by 28 per cent. Burning and grinding facilities have been optimized in recent years and the cement industry in Germany is planning to increase the use of fossil fuels by using waste products and by promoting the marketing of blended cements. The energy related carbon dioxide emissions were reduced by 3.6 million tonnes per year from 1987 to 1999 in the German cement industry as a result of these efforts. The use of waste products has also been increased from 4 to 23 per cent during this same time period and the clinker portion in cement has been decreased from 86 to 80.6 per cent. Granulated blast-furnace slag and unburned limestone has become the main constituent in cement. This paper also discussed the extent to which other instruments such as emissions trading, joint implementation and the clean development mechanism will have on the future of the cement industry. This paper was divided into several sections entitled: (1) voluntary agreement on climate change, (2) improvement in manufacturing processes, (3) optimization of existing kilns, (4) waste heat recovery, (5) reduction of electric power consumption, (6) remaining energy reduction potentials, (7) promotion of blended cement consumption, (8) market development, (9) use of secondary fuels, (10) greenhouse gas emissions, (11) energy related carbon dioxide emissions, (12) carbon dioxide emissions from the calcination of limestone, and (13) other greenhouse gas emissions. 3 tabs., 9 figs.

  9. GREENHOUSE GASES FROM SMALL-SCALE COMBUSTION DEVICES IN DEVELOPING COUNTRIES, CHARCOAL-MAKING KILNS IN THAILAND

    Science.gov (United States)

    The report gives results of measurements of airborne emissions, during typical operating conditions, from charcoal-making kilns commonly used in the developing world. The kilns tested were of five types: brick beehive, mud beehive, earth mound, rice husk mound, and single (oil) d...

  10. Antioxidant enzymes status and reproductive health of adult male workers exposed to brick kiln pollutants in Pakistan.

    Science.gov (United States)

    Jahan, Sarwat; Falah, Samreen; Ullah, Hizb; Ullah, Asad; Rauf, Naveed

    2016-07-01

    The present study was designed to study the effect of brick kilns emissions on the reproductive health and biochemical status of brick kiln workers and people living in the area near brick kilns. Body mass index (BMI) was significantly reduced in brick makers, carriers, and bakers compared to the control. Red blood cells count and hematocrit (%) were significantly high in brick bakers while MCH was significantly reduced in brick makers and brick bakers. Heavy metals (lead, cadmium, and chromium) concentration in whole blood of the brick kiln workers were significantly higher as compared to the control. Antioxidant enzymes (CAT, SOD, POD, GSH, and GR) were significantly reduced in brick kiln workers as compared to the control while TBARS level were significantly high in brick bakers as compared to the control. Plasma leutinizing hormone (LH) was significantly high in brick bakers while testosterone concentrations were significantly reduced in brick makers, carriers, and bakers. The present study shows that brick kiln workers and people living in the brick kiln vicinity are exposed to heavy metals and other pollutants that is a serious threat to their health. Alternate technology is needed to be developed and brick kilns should be replaced.

  11. Guidelines for Controlling Indoor Air Quality Problems Associated with Kilns, Copiers, and Welding in Schools. Technical Bulletin.

    Science.gov (United States)

    Turner, Ronald W.; And Others

    Guidelines for controlling indoor air quality problems associated with kilns, copiers, and welding in schools are provided in this document. Individual sections on kilns, duplicating equipment, and welding operations contain information on the following: sources of contaminants; health effects; methods of control; ventilation strategies; and…

  12. Osteotransductive bone cements.

    Science.gov (United States)

    Driessens, F C; Planell, J A; Boltong, M G; Khairoun, I; Ginebra, M P

    1998-01-01

    Calcium phosphate bone cements (CPBCs) are osteotransductive, i.e. after implantation in bone they are transformed into new bone tissue. Furthermore, due to the fact that they are mouldable, their osteointegration is immediate. Their chemistry has been established previously. Some CPBCs contain amorphous calcium phosphate (ACP) and set by a sol-gel transition. The others are crystalline and can give as the reaction product dicalcium phosphate dihydrate (DCPD), calcium-deficient hydroxyapatite (CDHA), carbonated apatite (CA) or hydroxyapatite (HA). Mixed-type gypsum-DCPD cements are also described. In vivo rates of osteotransduction vary as follows: gypsum-DCPD > DCPD > CDHA approximately CA > HA. The osteotransduction of CDHA-type cements may be increased by adding dicalcium phosphate anhydrous (DCP) and/or CaCO3 to the cement powder. CPBCs can be used for healing of bone defects, bone augmentation and bone reconstruction. Incorporation of drugs like antibiotics and bone morphogenetic protein is envisaged. Load-bearing applications are allowed for CHDA-type, CA-type and HA-type CPBCs as they have a higher compressive strength than human trabecular bone (10 MPa).

  13. 邢窑的艺术成就%The Artistic Achievement of Xing Kiln

    Institute of Scientific and Technical Information of China (English)

    毕翼飞; 毕南海

    2013-01-01

    Xing kiln is the important kiln in China’s kiln history. It burns white, bright and smooth porcelain Production. It opens the door to firing white porcelain. The production has broad shape, excellent decorations and deep rich cultural elements. It is a wonderful art form in Chinese Porcelain history.%邢窑是我国历史上重要的烧瓷窑场。它烧造出洁白莹润的白瓷制品,开创了我国烧造白瓷的先河。其器物造型气势博大、装饰技艺精湛,富含深邃的文化元素,是我国陶瓷百花园中的一朵奇葩。

  14. Application of the dynamic model of Saeman to an industrial rotary kiln incinerator: numerical and experimental results.

    Science.gov (United States)

    Ndiaye, L G; Caillat, S; Chinnayya, A; Gambier, D; Baudoin, B

    2010-07-01

    In order to simulate granular materials structure in a rotary kiln under the steady-state regime, a mathematical model has been developed by Saeman (1951). This model enables the calculation of the bed profiles, the axial velocity and solids flow rate along the kiln. This model can be coupled with a thermochemical model, in the case of a reacting moving bed. This dynamic model was used to calculate the bed profile for an industrial size kiln and the model projections were validated by measurements in a 4 m diameter by 16 m long industrial rotary kiln. The effect of rotation speed under solids bed profile and the effect of the feed rate under filling degree were established. On the basis of the calculations and the experimental results a phenomenological relation for the residence time estimation was proposed for the rotary kiln.

  15. Colorectal cancer and non-malignant respiratory disease in asbestos cement and cement workers. Studies on mortality, cancer morbidity, and radiographical changes in lung parenchyma and pleura

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsson, K.

    1993-09-01

    Radiologically visible parenchymal changes (small opacities >= 1/0;ILO 1980 classification) were present in 20% of a sample of workers (N=174), employed for 20 years (median) in an asbestos cement plant. Exposure-response relationships were found, after controlling for age and smoking habits. In a sample of asbestos cement workers with symptoms and signs suggestive of pulmonary disease (N=33), increased lung density measured by x-ray computed tomography, and reduced static lung volumes and lung compliance was found. In a cohort of asbestos cement workers (N=1.929) with an estimated median exposure of 1.2 fibres/ml, the mortality from non-malignant respiratory disease was increased in comparison to a regional reference cohort (N=1.233). A two-to three-fold increase of non-malignant respiratory mortality was noted among workers employed for more than a decade in the asbestos cement plant, compared to cement workers (N=1.526), who in their turn did not experience and increased risk compared to the general population. In the cohorts of asbestos cement and cement workers, there was a tow-to three-fold increased incidence of cancer in the right part of the colon, compared to the general population as well as to external reference cohorts of other industrial workers (N=3.965) and fishermen (N=8.092). A causal relation with the exposure to mineral dust and fibres was supported by the findings of higher risk estimated in subgroups with high cumulated asbestos doses or longer duration of cement work. The incidence of cancer in the left part of the colon was not increased. Morbidity data, but not mortality data, disclosed the subsite-specific risk pattern. Both asbestos cement workers and cement workers has an increased incidence of rectal cancer, compared with the general population, and with the fishermen. The risk was, however, of the same magnitude among the other industrial workers. 181 refs.

  16. Plastics wastes as secondary fuel in a cement plant; Residuos plasticos como combustible secundario en una cementera

    Energy Technology Data Exchange (ETDEWEB)

    Miguel, R.; Irasarri, L.; Arnaiz, S.; Cacho, I.

    2000-07-01

    The use of secondary fuel derived from plastics wastes from municipal source has been tested in an industrial cement plant. The recovered materials have been conditioned in order to fulfill the texture, composition and energetic requirements of the cement kiln. The performed long-term trials have shown the stability of the industrial facility during the operation with this alternative fuels. Several controls carried out over gaseous emissions confirmed the absence of differences in the emitted pollutant levels when compared with normal operation. The quality of the obtained clinker, checked using the established standard measurements, was found identical to the one in a clinker prepared using conventional fuels. The LCA (Life Cycle Analysis) tool was applied to evaluate a series of environmental impacts and proved that the energetic valorization alternative is more favourable then the disposal practice. Finally, a positive economical balance reinforced the option of energy recovery previously supported by favourable technical and environmental considerations. (Author) 16 refs.

  17. Research progress on catalytic reduction technique for denitration of cement flue gas%水泥窑炉烟气催化还原脱硝技术研究进展

    Institute of Scientific and Technical Information of China (English)

    房晶瑞; 马忠诚; 汪澜

    2013-01-01

    Cement production is one of the highest NOx emission industries, where the post-combustion control technology should be utilized in future because the combustion control technology used is difficult to meet the enhanced demand of environmental protection and emission standard. Selective catalytic reduction technique is the most efficient denitration technology and has been widely used in the field of power plants. However, its utilization in cement industry is relatively few because the commercial SCR technique is not applicable to the condition and component of the exhausted gas from cement kilns. This paper briefly introduced the mechanism of selective catalytic reduction process, reaction mechanism, concluded the application of SCR in cement kilns and discussed the research focus on catalysts for denitration of cement kilns.%水泥工业是NOx的高排放行业,现有的燃烧控制技术难以满足日益提高的环保要求,因此烟气脱硝技术在水泥工业的应用将势在必行.选择性催化还原(SCR)脱硝技术是脱硝率最高的烟气脱硝技术,在燃煤电厂已有较大规模的应用,但是在水泥工业中的研究和应用相对滞后.简要介绍了SCR脱硝技术工作原理及其在水泥窑炉的应用现状,总结了催化材料研究和应用进展,探讨了水泥窑炉NOx减排用SCR脱硝技术和催化材料的研究方向.

  18. Reducing firing of an early pottery making kiln at Batan Grande, Peru: A Moessbauer study

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, U. [Technische Universitaet Muenchen, Physik-Department E15 (Germany); Gebhard, R. [Praehistorische Staatssammlung (Germany); Haeusler, W.; Hutzelmann, T. [Technische Universitaet Muenchen, Physik-Department E15 (Germany); Riederer, J. [Rathgen-Forschungslabor (Germany); Shimada, I. [Southern Illinois University (United States); Sosa, J.; Wagner, F.E. [Technische Universitaet Muenchen, Physik-Department E15 (Germany)

    1999-11-15

    Material from field firing experiments using a 2,700-year old Formative kiln at Batan Grande, Peru, was studied by X-ray diffraction and Moessbauer spectroscopy. The experiments explore the technology involved in producing the gray and black reduced ware for which Cupisnique and other Formative ceramics are justly known. During firing, the iron-bearing compounds in clays undergo characteristic changes which depend on kiln temperature and atmosphere. These changes can be observed in the Moessbauer spectra. By comparing spectra of an appropriate clay fired in field experiments and in the laboratory with the spectra of ancient ceramics, a description of Formative firing techniques in a reducing environment is attempted.

  19. Indications of the presence of Middle Neolithic pottery kilns at Magoula Imvrou Pigadi, SW Thessaly, Greece

    Directory of Open Access Journals (Sweden)

    Nina Kyparissi-Apostolika

    2012-12-01

    Full Text Available Red hot deposits were uncovered on the western edge of a Middle Neolithic settlement. With the extension of the excavation, a wide space of about 10m2, confined between two clay walls, very much affected by high temperatures, was uncovered. A number of vases almost totally complete after their preservation and a clay model of a kiln were unearthed. Additionally, clay remains of constructions were uncovered. The whole context suggests an area where pottery firing activities took place. The possibility that these kilns could have worked as a specialized craft workshop for other settlements in the area is discussed.

  20. Modeling of the combined heat exchanges in the ceramic firing kilns

    Energy Technology Data Exchange (ETDEWEB)

    El Hayek, M.; Lybaert, P.; Meunier, H. [Faculte Polytechnique de Mons (Belgium)

    1993-12-31

    A new methodology for the simulation of batch ceramic firing kilns is presented. A classical continuum approach is used in the free space and a quasi-continuum one in the load stacking area. This latter is replaced by an homogeneous porous medium with apparent equivalent characteristics. A flux model is used to take radiation heat transfer into account. The conduction in the load pieces is managed by the usual resistance scheme. The whole procedure is applied to a real refractory bricks firing kiln and shows promising features. (Authors). 8 refs., 4 figs.

  1. Study on trace element of Yue ware unearthed at different kiln sites

    Institute of Scientific and Technical Information of China (English)

    吴隽; 李家治; 郭景坤; 徐锴; 陈宝林

    1999-01-01

    The contents of trace element of Yue ware excavated in Shaoxing, Shanglinhu, Shangyu kiln sites and Hangzhou palace were analyzed by NAA technique. The data of trace element compositions were treated by statistical analysis. It is found that the sources of raw materials used in Shaoxing, Shanglinhu, Shangyu kiln sites are different and stable. Especially the discriminant function predicted for porcelain bodies provides high discriminatory power according to production site. It shows that Yue ware specimens excavated in Hangzhou palace were fired in Shanglinhu. It indicates the special function of trace element in the studies on site identification.

  2. TK7 High-Temperature Tunnel Kiln Computer Control System of SRIC Thailand

    Institute of Scientific and Technical Information of China (English)

    QIN Shukai; YANG Yinghua; CHEN Xiaobo; ZHANG Yazhong; BU Youkang; GUO Xiaojun

    2007-01-01

    Based on the TK7 high-temperature tunnel kiln computer control system, this article describes the control line system, the automatic loop control which has been realized in firing zone temperature, inner and bottom pressure and flow, and logic control of kiln doors and pusher, etc. In addition, this system integrates the product information management system of magnesite brick and efficiently ensures the important process parameters. During three months performance of the control system, all parameters and energy consumption have turned out a good result.

  3. 立窑水泥与回转窑水泥使用性能比较%The applying property contrast between vertical kiln cement and rotary kiln cement

    Institute of Scientific and Technical Information of China (English)

    周惠群

    2002-01-01

    立窑水泥与回转窑水泥在使用性能上存在差异,分析了两种水泥制成的混凝土在性能上的差别,通过大量的统计数据,从生产工艺特点对两种水泥使用性能差异的原因进行了分析。

  4. Mineral resource of the month: hydraulic cement

    Science.gov (United States)

    van Oss, Hendrik G.

    2012-01-01

    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  5. Evaluation of shredder residue as cement manufacturing feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Boughton, Bob [California Environmental Protection Agency, Department of Toxic Substances Control, Office of Pollution Prevention and Technology Development, 1001 I Street, P.O. Box 806, Sacramento, CA 95812 (United States)

    2007-09-15

    Metal recycling from automobiles, appliances and scrap steel occurs at over 200 dedicated metal shredding operations in the US. Shredder residue (SR) consists of glass, rubber, plastics, fibers, dirt, and fines that remain after ferrous and non-ferrous metals have been removed. Over 3 million tonnes of SR generated in the US each year are landfilled. The results of a previous end-of-life impact assessment showed that use of SR as a fuel supplement for cement manufacturing was environmentally beneficial to the current practice of landfilling and appears better in comparison to the other management methods studied. However, because many reuse and recycling options may not be cost effective, there is a need for further study. Simplistic methods to separate SR into energy and mineral rich streams may facilitate the use of a sizable fraction of SR. Due to the large scale of the cement industry in the US, a significant amount of SR is recoverable. The goal of this study was to identify the feedstock quality parameters needed to satisfy kiln operators and then to assess the mechanical means necessary to process SR into material acceptable as coal and mineral substitutes. Field tests were conducted to separate and beneficiate the coarse SR waste stream. Density separation techniques commonly used by shredders in the past were tested to separate rubber and plastics from non-combustibles and contaminants (e.g., PVC and copper wire). A fraction constituting about 30 wt% of the total SR had fuel characteristics mirroring those of coal. However, remaining levels of potentially problematic constituents (e.g., total chlorine and heavy metals) may limit use to a low relative addition rate at some kilns. An economic review of a full-scale separation system showed that processing SR appears to be economically marginal considering avoided landfilling costs alone. However, significant economic benefits would result from additional non-ferrous metals recovery (namely copper). The

  6. Cement from magnesium substituted hydroxyapatite.

    Science.gov (United States)

    Lilley, K J; Gbureck, U; Knowles, J C; Farrar, D F; Barralet, J E

    2005-05-01

    Brushite cement may be used as a bone graft material and is more soluble than apatite in physiological conditions. Consequently it is considerably more resorbable in vivo than apatite forming cements. Brushite cement formation has previously been reported by our group following the mixture of nanocrystalline hydroxyapatite and phosphoric acid. In this study, brushite cement was formed from the reaction of nanocrystalline magnesium-substituted hydroxyapatite with phosphoric acid in an attempt to produce a magnesium substituted brushite cement. The presence of magnesium was shown to have a strong effect on cement composition and strength. Additionally the presence of magnesium in brushite cement was found to reduce the extent of brushite hydrolysis resulting in the formation of HA. By incorporating magnesium ions in the apatite reactant structure the concentration of magnesium ions in the liquid phase of the cement was controlled by the dissolution rate of the apatite. This approach may be used to supply other ions to cement systems during setting as a means to manipulate the clinical performance and characteristics of brushite cements.

  7. POZZOLAN AND CEMENTS WITH POZZOLAN

    Directory of Open Access Journals (Sweden)

    Hasan KAPLAN

    1995-02-01

    Full Text Available Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, cement with pozzolan is produced by adding the pozzolan, which has a large reservoir in the country, in cement in sertain amount. However this type of cement is consumed in the construction sector, sortage of scientific investigation and speculative news on the subject.are worried the users and producers. In this paper, prior to an experimental study on the cements having pozzolan additive, historical development of pozzolan, reservoir of Turkiye, and comparison with portland cement is carried out. Advantages and disadvantages of pozzolan are also discussed in some points.

  8. Modern lining schemes for kilns in the lime industry with particular reference to standard shaft kilns. Neuzeitliches Zustellkonzept fuer die Oefen der Kalkindustrie unter besonderer Beruecksichtigung der Normalschachtoefen

    Energy Technology Data Exchange (ETDEWEB)

    Dobrowsky, F.; Steinwender, R.

    1990-08-01

    Over the last 40 years lime shaft kilns have developed in many directions, the improvement in the lime quality, the extension of the particle size range and the saving in energy being predominant. These conversions had the effect that the refractory linings also had to be adapted to suit the requirements. High-grade insulating materials reduce the radiation from the kiln shell in spite of reduced wall thicknesses. Chromium-free periclase-spinel bricks are being used increasingly for the burning zone linings. Another advantage of the spinel bricks is that the broken brick material can be deposited in waste-disposal sites due to the absence of chromium, especially Cr{sup 6+}. (orig./HK).

  9. Energy Efficient Microwave Hybrid Processing of Lime for Cement, Steel, and Glass Industries

    Energy Technology Data Exchange (ETDEWEB)

    Fall, Morgana L; Yakovlev, Vadim; Sahi, Catherine; Baranova, Inessa; Bowers, Johnney G; Esquenazi\t, Gibran L

    2012-02-10

    MAT in the US lime industry. This estimate showed that 7.3 TBTU/year could be saved, with reduction of 270 MMlbs of CO2 emissions, and $29 MM/year in economic savings. Taking into account estimates for MAT implementation in the US cement industry, an additional 39 TBTU/year, 3 Blbs of CO2 and $155 MM/year could be saved. One of the main remaining barriers to commercialization of MAT for the lime and cement industries is the sheer size of production. Through this project, it was realized that a production size MAT rotary calciner was not feasible, and a different approach was adapted. The concept of a microwave post heat section located in the upper portion of the cooler was devised and appears to be a more realistic approach for MAT implementation. Commercialization of this technology will require (1) continued pilot scale calcining demonstrations, (2) involvement of lime kiln companies, and (3) involvement of an industrial microwave equipment provider. An initial design concept for a MAT post-heat treatment section was conceived as a retrofit into the cooler sections of existing lime rotary calciners with a 1.4 year payback. Retrofitting will help spur implementation of this technology, as the capital investment will be minimal for enhancing the efficiency of current rotary lime kilns. Retrofits would likely be attractive to lime manufacturers, as the purchase of a new lime kiln is on the order of a $30 million dollar investment, where as a MAT retrofit is estimated on the order of $1 million. The path for commercialization lies in partnering with existing lime kiln companies, who will be able to implement the microwave post heat sections in existing and new build kilns. A microwave equipment provider has been identified, who would make up part of the continued development and commercialization team.

  10. US cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  11. A Song Period Kiln-site at Chalu in Ninghai County, Zhejiang%浙江宁海县岔路宋代窑址

    Institute of Scientific and Technical Information of China (English)

    宁波市文物考古研究所; 宁海县文管会办公室

    2003-01-01

    In 1998, a kiln-site of the Song period was revealed at Chalu Town in Ninghai County, Zhejiang Province, in an excavation area of about 1,000 sq m. The vestiges discovered include a section of kiln-foundations, two sections of stone walls and six Ming period tombs. The kiln-site yielded a large amount of porcelain and a variety of kiln implements. The former belongs mainly to the type of bowl; the latter are for saggering, spurring and separating. The porcelain is largely coated with celadon glaze and decorated chiefly with incised, impressed and openworked dragon head and sea wave design. Some products and kiln implements bear inscriptions. The kiln must have functioned in the middle and late Northern Song period and belonged to the Yue system. The kiln implements unearthed in great numbers constitute valuable material to the study of firing technology.

  12. Application of Alternative Fuels in Cement Kiln%替代燃料在水泥窑中的应用

    Institute of Scientific and Technical Information of China (English)

    韩力

    2010-01-01

    @@ 1 水泥行业燃料发展趋势 水泥行业是高能耗、高污染的行业之一,同时也是我国节能减排的重点行业之一.我国水泥窑大都使用煤做燃料;众所周知煤是不可再生的自然资源,随着我国的工业快速发展,煤炭的供应压力越来越大,长期以来煤炭在一次能源消费比例中一直占首位.

  13. A SYSTEM AND A METHOD FOR PREDICTION OF NOx EMISSION AND/OR FREE LIME CONCENTRATION IN A CEMENT KILN

    DEFF Research Database (Denmark)

    2008-01-01

    representing a burning zone; wherein the method further comprises the step of performing partial least squares regression on said collected at least one process measurement and said collected at least one item of image data to calculate a soft sensor output. Hereby is achieved, among other things...

  14. Quantification of the Reduced Environmental Impacts with Use of Co-Processing in Cement Kilns in India

    OpenAIRE

    Ankur Tiwary; Garima Sharma; Gupta, P K

    2014-01-01

    Coupled with resource conservation and reduced carbon emissions, co-processing technology is a preferable alternative for sound and environmental friendly waste disposal over incinerators & non-scientific methods. It is not only solution to the waste disposal menace, but also reduces burden on secured landfills & TSDFs. Apart from using energy and material value of wastes, co-processing not only fixes the inorganic content of the wastes within the clinker, but also, it destroys the wa...

  15. Advances in Glass Ionomer Cements

    OpenAIRE

    KAYA, Dt. Tuğba; TİRALİ, Yard. Doç. Dr. Resmiye Ebru

    2013-01-01

    In recent years there have been a number of innovations and developments with respect to glass ionomer cements and their applications in clinical dentistry. This article considers some of the recent outstanding studies regarding the field of glass ionomer cement applications, adhesion and setting mechanisms, types, advantage and disadvantages among themselves and also to enhance the physical and antibacterial properties under the title of 'Advances in Glass Ionomer Cements'. As their biologic...

  16. Cement penetration after patella venting.

    Science.gov (United States)

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement.

  17. Pulmonary dysfunctions, oxidative stress and DNA damage in brick kiln workers.

    Science.gov (United States)

    Kaushik, R; Khaliq, F; Subramaneyaan, M; Ahmed, R S

    2012-11-01

    Brick kilns in the suburban areas in developing countries pose a big threat to the environment and hence the health of their workers and people residing around them. The present study was planned to assess the lung functions, oxidative stress parameters and DNA damage in brick kiln workers. A total of 31 male subjects working in brick kiln, and 32 age, sex and socioeconomic status matched controls were included in the study. The lung volumes, capacities and flow rates, namely, forced expiratory volume in first second (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC, expiratory reserve volume, inspiratory capacity (IC), maximal expiratory flow when 50% of FVC is remaining to be expired, maximum voluntary ventilation, peak expiratory flow rate and vital capacity were significantly decreased in the brick kiln workers. Increased oxidative stress as evidenced by increased malonedialdehyde levels and reduced glutathione content, glutathione S-transferase activity and ferric reducing ability of plasma were observed in the study group when compared with controls. Our results indicate a significant correlation between oxidative stress parameters and pulmonary dysfunction, which may be due to silica-induced oxidative stress and resulting lung damage.

  18. Beijing Bianyifang,No.1 of the 600-year "Kiln-roast Duck"

    Institute of Scientific and Technical Information of China (English)

    Ma Wei

    2006-01-01

    @@ The brand of Bianyifang was established in A.D.1416 (Yongle 14th, Ming dynasty), 590 years ago. It is one of the oldest restaurants in China, famous for its roast duck. Its unique method of kiln-roasting has been its trademark all throughout its history.

  19. Characterization, stability, and plant effects of kiln-produced wheat straw biochar.

    Science.gov (United States)

    O'Toole, A; Knoth de Zarruk, K; Steffens, M; Rasse, D P

    2013-01-01

    Biochar is a promising technology for improving soil quality and sequestering C in the long term. Although modern pyrolysis technologies are being developed, kiln technologies often remain the most accessible method for biochar production. The objective of the present study was to assess biochar characteristics, stability in soil, and agronomic effects of a kiln-produced biochar. Wheat-straw biochar was produced in a double-barrel kiln and analyzed by solid-state C nuclear magneticresonance spectroscopy. Two experiments were conducted with biochar mixed into an Ap-horizon sandy loam. In the first experiment, CO efflux was monitored for 3 mo in plant-free soil columns across four treatments (0, 10, 50, and 100 Mg biochar ha). In the second experiment, ryegrass was grown in pots having received 17 and 54 Mg biochar ha combined with four N rates from 144 to 288 kg N ha. Our kiln method generated a wheat-straw biochar with carbon content composed of 92% of aromatic structures. Our results suggest that the biochar lost impact on ryegrass yields.

  20. Palaeointensity determination on an early medieval kiln from Switzerland and the effect of cooling rate

    Science.gov (United States)

    Donadini, F.; Kovacheva, M.; Kostadinova, M.; Hedley, I. G.; Pesonen, L. J.

    The archaeomagnetic intensity reference curve for Western Europe lacks data during the period from 600 to 1000 AD. Baked clay from the walls of a pottery kiln at Reinach (Switzerland), archaeologically dated to the beginning of the 9th century AD, and having a 14C date of 1250 ± 50 BP, was investigated in order to refine the ancient geomagnetic field intensity during this period. A previous study to test the suitability of the material has shown that the magnetic properties of the baked clay from this Reinach kiln are appropriate for an archaeomagnetic study, and furthermore an archaeomagnetic directional date agrees well with the 14C date. A series of palaeointensity measurements was carried out in Sofia (Bulgaria). Here we present the results obtained from the same material, as performed in Helsinki (Finland) using different techniques. The comparison of the results shows significant differences between the two datasets. Based on the literature data, the discrepancy can be explained in terms of the different cooling rates of the samples used during the experiments in the two laboratories. Nevertheless, the results show that the geomagnetic field intensity had a high mean value of 86.85 ± 1.49 μT when the kiln was last used. This observation is consistent with recent studies from France covering the period during which the Reinach kiln functioned.

  1. Effect of kilning and milling on the dough-making properties of oat flour

    NARCIS (Netherlands)

    Londono, D.M.; Smulders, M.J.M.; Visser, R.G.F.; Gilissen, L.J.W.J.; Hamer, R.J.

    2015-01-01

    Oats are mostly used for porridges, flakes, and cereal breakfast. The current oat kilning and milling methods are suited for these purposes. Bread-making applications have been explored, but the bread quality results are far from optimal. The goals of this study were to determine whether infrared (I

  2. Energy efficiency of an innovative vertical axial rotary kiln for pottery production

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Forero Núñez

    2015-01-01

    Full Text Available Colombia is a remarkablecoal producer and exporter worldwide; several sectors use this resource for electricity and thermal energy production. Among them, the ceramic industry consumed 118,590 tons in 2011. Most of the pottery production companies in this country arelocated in rural areas and use old coal fired kilns with low energy efficiencies, generating environmental effects to the population nearby. Despite of the importance of these industries to the small rural economies, the government agencies have closed them due to the lack of development on cleaner devices. This work aims to analyze the thermal behavior of an innovative vertical axial rotary kiln for pottery production, and the energy efficiency varying operation mode. The kiln operated during seven hours needed three hours for stabilizing sintering temperature at 800°C. The mean temperatures of the loading, drying, sintering and cooling stage were 204°C, 223°C, 809°C and 321°C respectively. The convection and radiation heat losses were 15 % whereas the flue gas heat losses 18 %.During continuous operation, the kiln energy efficiency was about 60 %. This design proven to reach the temperatures required in the firing stage of the pottery production; moreover, a gas fuel was fuelled making the process cleaner and more efficient than coal-fired systems.

  3. Experimental and theoretical investigation on unburned coal char burnout in a pilot-scale rotary kiln

    Energy Technology Data Exchange (ETDEWEB)

    Federico Cangialosi; Francesco Di Canio; Gianluca Intini; Michele Notarnicola; Lorenzo Liberti; Giulio Belz; Pompilio Caramuscio [Technical University of Bari, Taranto (Italy). Department of Environmental Engineering and Sustainable Development

    2006-11-15

    Oxidation reactivity studies are imperative for improving carbon re-burn technologies and valuing the heat content of unburned carbon within coal combustion ashes. Non-isothermal, thermal gravimetric analysis (TGA) was used to examine the oxidation kinetics of unburned carbon in coal combustion fly ashes having different particle size distributions; TGA results were related to combustion efficiencies as measured in a bench-scale rotary kiln. The activation energy and pre-exponential factor were determined for the chemically-controlled reaction regime; the transition temperatures between chemically-controlled and partially diffusion-controlled combustion regimes were obtained for unburned carbon particles of different sizes. After the oxidation reaction rates were evaluated, the residence time distribution (RTD) of fly ashes in the rotary kiln were experimentally measured and the mean residence times related to process parameters, including the rotating velocity and kiln inclination. By comparing these results with an advective-dispersive model, the axial dispersion coefficient of fly ashes was determined. The reaction rates obtained by thermal analyses and the RTDs were used to predict combustion efficiencies within the kiln and oxidation conditions of unburned carbon using various processing options. 21 refs., 6 figs., 4 tabs.

  4. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE–RBS

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Z. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Zhang, K. [School of History and Culture, Sichuan University, Chengdu 610064 (China); Xia, C.D.; Liu, M.T.; Zhu, J.J. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); An, Z., E-mail: anzhu@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Bai, B., E-mail: baibin@scu.edu.cn [School of History and Culture, Sichuan University, Chengdu 610064 (China)

    2015-03-01

    Highlights: •We analyzed 61 unearthed porcelain shards in Yuan Dynasty by PIXE–RBS. •An electron gun was installed to solve the electric charge accumulations. •The factor analysis was performed for the element compositions. •The “exotic group” porcelain samples unearthed were produced locally. -- Abstract: A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271–1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB{sub 6} crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907–960 A.D.) had been

  5. The Health Costs of The Brick Kilns Emissions in Peshawar: A Policy Analysis.

    Directory of Open Access Journals (Sweden)

    Muhammad Rafiq

    2014-12-01

    Full Text Available Air Pollution especially resulting from Brick kiln is a major Environmental problem of Pakistan in general and Peshawar in Particular. World Health Organization in a recent document has declared Peshawar as the sixth most polluted city of the world. We in our latest study have tried to estimate the health cost related to the release of PM10 from these kilns. For the said purpose, we collected primary data pertaining to pollution and socio-economic of the brick producing and nearby areas. We collected socio economic data from respondents living within 3 kilometer of the kilns and also from a control group which were further away. Sample size was set at two hundred households, i.e. one hundred households were taken from the kilns group and another100 samples from the control group. We have used health diary method to collect health information from the respondents. We have estimated two reduced form equations, i.e., health production function and demand for mitigation cost using Poisson and Tobit regression models. The PM10 level in the kilns region was very high it was at average level is 415ug/m3, and the control group the PM10 level is low it was 180 ug/m3. Our regression analysis estimated that by reducing PM10 to safe level, every individual can save PKR 3315 (or USD 31 per annum through only mitigation cost. Total welfare gain to reduce air quality to safe level through mitigation cot for district Peshawar is PKR 6692.985 million or (PKR 6.7 billion per annum (USD 63.44 million. Besides, the productivity loss by individuals is estimated as .36 day per annum. The monetary benefit to avoid from the restricted day of working is PKR 198 for one household whereas for the city the monetary benefit of bringing down the PM10 level is PKR 107.935 million (or USD 1.023 million. The study is suggesting implementing of the ban on the use of rubber as a fuel in these bricks kiln. The study also recommends that these kiln owners be punished/ taxed as per

  6. Compacting of fly dusts from cupola and electric arc furnace

    Directory of Open Access Journals (Sweden)

    D. Baricová

    2012-01-01

    Full Text Available Recycling and utilization of dust waste is important not only from the point of view of its usage as an alternative source of raw materials, but regarding the environmental problems also. Dust emissions arise from thermal and chemical or physical processes and mechanical actions. Two kinds of fl y dusts from cupola furnaces (hot and cold blast cupola furnace and fl y dust from electric arc furnace were used by experiments. They were pelletized only with addition of water and briquetted with diff erent addition of water glass, bentonite and cement. Quality of briquettes was tested by compression – strength test and by break down test in green state, after drying and afterstoring (1 month.

  7. Eco-efficiency of the world cement industry: A data envelopment analysis

    Energy Technology Data Exchange (ETDEWEB)

    Oggioni, G., E-mail: oggioni@eco.unibs.i [University of Brescia, Faculty of Economics, Department of Quantitative Methods, IT-25122 Brescia (Italy); Riccardi, R., E-mail: riccardi@ec.unipi.i [University of Brescia, Faculty of Economics, Department of Quantitative Methods, IT-25122 Brescia (Italy); Toninelli, R., E-mail: roberta.toninelli@unifi.i [University of Pisa, Faculty of Economics, Department of Statistics and Applied Mathematics, IT-56124 Pisa (Italy)

    2011-05-15

    Chemical reactions and the combustion of dirty fuels, such as coal and petroleum coke (petcoke), that are used in cement production processes generate a significant amount of CO{sub 2} emissions. In this paper, we provide an eco-efficiency measure for 21 prototypes of cement industries operating in many countries by applying both a data envelopment analysis (DEA) and a directional distance function approach, which are particularly suitable for models where several production inputs and desirable and undesirable outputs are taken into account. To understand whether this eco-efficiency is due to a rational utilization of inputs or to a real carbon dioxide reduction as a consequence of environmental regulation, we analyze the cases where CO{sub 2} emissions can either be considered as an input or as an undesirable output. Empirical results show that countries where cement industries invest in technologically advanced kilns and adopt alternative fuels and raw materials in their production processes are eco-efficient. This gives a comparative advantage to emerging countries, such as India and China, which are incentivized to modernize their production processes.

  8. Effects on cement after partial replacement with burned joss paper ash.

    Science.gov (United States)

    Lin, D F; Huang, L S; Luo, H L; Weng, R S

    2012-12-01

    In the last ten years, as international environmental protection consciousness has increased, the study and applications of green building, green construction materials and energy savings as well as reduction of carbon dioxide have become urgent issues for governments. In Taiwan, joss papers are burned in more than 11,731 registered shrines or temples in traditional Chinese deity or ancestor worship ceremonies during special holidays or occasions. Instead of placing this large amount of burned joss paper ash (BJPA) in landfills, this study proposes recycling BJPA by replacing some cement with calcined BJPA (CBJPA) in mortar specimens. After BJPA samples were calcined at a high kiln temperature, mortar samples were created using CBJPA to replace cement at seven different levels: 0%, 5%, 10%, 15%, 20%, 25% and 30%. Tests like setting time and compressive strength were performed for macro-analyses; scanning electron microscopy-energy dispersive spectroscopy, X-ray diffraction and thermal gravimetric analysis/differential thermal analysis were carried out for the microstructure and chemical composition analyses. The test results showed that the compressive strengths of specimens with different levels of CBJPA replacement were apparently less than those of the control group (0% CBJPA) at all curing times. The compressive strength and setting time both decreased as the fraction of CBJPA in the mortar increased. Furthermore, because the hydration product did not cement and the mortar specimen structure was loose, the expected strength improvement from the pozzolanic reaction provided by the CBJPA was not clearly observed.

  9. Development of a monitoring scheme for preventive maintenance of the cement machinery.

    Science.gov (United States)

    Alhajjaji, Malek; Boubeker, Brahim; Eljoumani, Safia; Zamma, Abdellah; Idiri, Mohamed; Atik, Hafsa

    2016-01-01

    It was underscored that the optimization of policies of preventive maintenance has become a subject of much research. This article proposes a new optimal policy of preventive maintenance for the roller shaft system. It is divided into two main sections. The first proposes a new design of the shaft where the effect of preventive maintenance is integrated, and the second is developing a new control technique adapted to the new design. In this regard, we are interested in the shaft of rollers of the rotary kilns of cement. We have noted the stresses imposed to the axis of the roller. These constraints that have stemmed from the contact between tire and its support rollers. Currently the ultrasonic inspection method of the solid shaft in this situation poses disadvantages, for example, the obligation to stop the rotary Kiln and the difficulty of detecting and sizing defects (fatigue cracks). We propose in this study another approach, we recommend opting for a hollow shaft instead of a solid shaft with a minimum diameter that allows the control system to enter hollow shaft to show for inspection purposes. This will allow preventive control, in operation by the non-destructive technique of ultrasound. The analysis shows the different results of comparison between the axis of full and hollow cylinders, having the same dimensions and the same material and ultimately the most interesting is the same operation.

  10. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  11. Phosphate based oil well cements

    Science.gov (United States)

    Natarajan, Ramkumar

    The main application of the cement in an oil well is to stabilize the steel casing in the borehole and protect it from corrosion. The cement is pumped through the borehole and is pushed upwards through the annulus between the casing and the formation. The cement will be exposed to temperature and pressure gradients of the borehole. Modified Portland cement that is being used presently has several shortcomings for borehole sealant. The setting of the Portland cement in permafrost regions is poor because the water in it will freeze even before the cement sets and because of high porosity and calcium oxide, a major ingredient it gets easily affected by the down hole gases such as carbon dioxide. The concept of phosphate bonded cements was born out of considerable work at Argonne National Laboratory (ANL) on their use in stabilization of radioactive and hazardous wastes. Novel cements were synthesized by an acid base reaction between a metal oxide and acid phosphate solution. The major objective of this research is to develop phosphate based oil well cements. We have used thermodynamics along with solution chemistry principles to select calcined magnesium oxide as candidate metal oxide for temperatures up to 200°F (93.3°C) and alumina for temperatures greater than 200°F (93.3°C). Solution chemistry helped us in selecting mono potassium phosphate as the acid component for temperatures less than 200°F (93.3°C) and phosphoric acid solution greater than 200°F (93.3°C). These phosphate cements have performance superior to common Portland well cements in providing suitable thickening time, better mechanical and physical properties.

  12. Periclase spinel bricks in the cement industry. Periklas-Spinell-Steine in der Zementindustrie

    Energy Technology Data Exchange (ETDEWEB)

    Olbrich, M.; Dobrowsky, F.

    1989-10-01

    Intensified environmental requirements are leading some countries to abandon refractory products which contain chromium. The industry is being asked to develop corresponding products which are free from chrome ore so that substitution is possible without a break. In addition to spinel bricks which are produced by a reaction between Al{sub 2}O{sub 3} and MgO when the brick is fired there are also those containing spinel which has been prepared in advance. The present article makes a partial comparison of the two types with respect to their important physical test values. Details are also given of their thermomechanical and coating behaviours including a comparison with traditional magnesia chrome bricks. The comparison shows that the refractory industry is in a position to offer a complete, chrome-free, lining for rotary cement kilns which can even show improvements in quality. (orig.).

  13. Use of precalciners to remove alkali from raw materials in the cement industry. Final report, July 1978-July 1980

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, E.M.

    1980-07-01

    The objective of this work was to develop an efficient means of removing alkali metal compounds (alkalies) from high-alkali aluminosilicate raw materials of the type commonly used as part of cement raw mixes in order to increase the energy efficiency of cement manufacture. The intention of this project was to determine whether the high-alkali raw materials could be pyroprocessed separately to remove the alkalies before they entered the rotary kiln, where they would be mixed with the other raw feed components. If this could be achieved, considerable savings could be made in the energy required to remove alkalies, compared to conventional methods in which the cement raw mix must be treated as a whole. Two different methods of alkali removal were examined, namely, vaporization of alkalies at relatively low temperatures; and alkali-rich melt separation at relativey high temperatures. The results showed that the removal of alkalies by pyroprocessing of high-alkali raw feed components separate from the other cement raw mix components is not likely to be a practical alternative to the best available conventional precalciner technology. (LCL)

  14. Effect of Wood Dust on Respiratory Health Status of Carpenters

    OpenAIRE

    Mohan, Mamta; Aprajita; Panwar, Neeraj Kant

    2013-01-01

    Introduction: Occupational lung diseases form an important part of clinical medicine. Exposure to various chemicals or toxins which are manufactured or processed in industries are lethal for the workers in industries. Although these chemicals at workplace are known to invariably affect all body systems, lungs are most vulnerable to airborne hazards which are caused due to exposure to wood dust in welding, cement and wood industrial sectors.

  15. A study on respiratory problems and pulmonary function indexes among cement industry workers in Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    Ehsan Rafeemanesh

    2015-08-01

    Full Text Available Background: The respiratory system is the most vulnerable system in the cement industry. This study was conducted to determine the effects of occupational exposure to cement dust on the respiratory system more thoroughly. Material and Methods: In this cross sectional study an interviewer-administered questionnaire on socio-demographic characteristics and respiratory symptoms was completed and pulmonary function tests were carried out on 100 exposed and 120 non-exposed workers at the cement factory in Mashhad, Iran. The data was statistically analyzed by SPSS 16. Results: The mean of age and work duration in the exposed group was 37.5±6.3 and 10.7±5.4 years compared with the non-exposed group that was 36.1±7.1 and 10.1±5.7 years, respectively. Levels of exposure to inhalable cement dust in the exposed group were 23.13 mg/m3 (higher than national occupational exposure limits for such particles. Among the exposed group, respiratory symptoms as cough (6% vs. 0.8% of the non-exposed and sputum (7% vs. 0.8% of the nonexposed were significantly more prevalent (p < 0.05. Forced expiratory flow 25–75% (FEF25–75% was significantly lower in the exposed workers compared with non-exposed ones (p < 0.05. Also forced expiratory volume in 1 s / forced vital capacity (FEV1/FVC and FEF25–75% had a reverse correlation with the length of employment (p = 0.000 and p = 0.003, respectively. Conclusions: The findings of this study showed that occupational exposure to cement dust could be a significant factor of respiratory system dysfunction. Strict implementation of a respiratory protection program is recommended in cement industries. Med Pr 2015;66(4:471–477

  16. Cemented total hip arthroplasty with Boneloc bone cement.

    Science.gov (United States)

    Markel, D C; Hoard, D B; Porretta, C A

    2001-01-01

    Boneloc cement (WK-345, Biomet Inc, Warsaw, Ind) attempted to improve cement characteristics by reducing exotherm during polymerization, lowering residual monomer and solubility, raising molecular weight, and lowering airborne monomer and aromatic amines. To study the efficacy of this cement, a selected group of 20 patients were prospectively enrolled and followed up after hip arthroplasty. All components were cemented. During the enrollment period, approximately 70 other hip arthroplasties were performed. Clinical evaluation was based on the Harris hip score. Radiographic evaluation was based on assessment of position of the components, subsidence, and/or presence of radiolucencies. Patients had follow-up for an average of 42 months (11 to 58 months); 1 was lost to follow-up. Of these, 7 (35%) had failure at last follow-up. Despite its initial promise, Boneloc cement had an unacceptably high failure rate over a relatively short follow-up period and is not recommended for use. Despite the longevity and odor toxicity problems with conventional bone cement, new cement technologies must be approached with caution.

  17. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  18. PAH exposure biomarkers are associated with clinico-chemical changes in the brick kiln workers in Pakistan.

    Science.gov (United States)

    Kamal, Atif; Malik, Riffat Naseem; Martellini, Tania; Cincinelli, Alessandra

    2014-08-15

    In this study we investigated the clinico-chemical parameters and the level of exposure of brick kiln workers to polycyclic aromatic hydrocarbons (PAHs) in Punjab (Pakistan). The brick kiln workers and a non-occupationally exposed group were recruited for comparative analysis of urinary biomarkers of PAH exposure (i.e. 1-hydroxypyrene (1-OHPyr), α-naphthol and β-naphthol) and blood level of superoxide dismutase (SOD), as a biomarker of oxidative stress and other hematologic parameters. Questionnaires were used to document information on socio-demographic characteristics of all the subjects. The analysis of urinary biomarkers showed higher median concentrations of 1-OHPyr, and α- and β-naphthols in brick kiln workers (1.53, 3.65 and 1.53 μmol/mol-Cr, respectively) than non-occupationally exposed group (0.62, 0.64 and 0.66 μmol/mol-Cr, respectively). The 1-OHPyr in brick kiln workers was above the occupational exposure level. Among the clinical parameters of brick kiln workers, hemoglobin (Hb) and red blood cells (RBCs) were very low and closely associate with 1-OHPyr and β-naphthol. Additionally, the white blood cells (WBCs) and superoxide dismutase (SOD) were also elevated in brick kiln workers, which suggested inflammatory symptoms and high oxidative stress. The results show that regardless of possibly being affected by the poor nutrition, the anemic state and hematological changes observed in brick kiln workers may be associated with their exposure to smoke present in the environment of brick kilns.

  19. Kilns of Glass in Barcelona and its surroundings (14th-16th centuries

    Directory of Open Access Journals (Sweden)

    Cañellas i Martínez, Silvia

    2008-12-01

    Full Text Available In spite of the municipal regulations of the Middle Ages about the prohibition of setting up kilns of glass in the cities, some remained for a long time. Barcelona is a clear example. This article is about our kilns and the information has been taken from the Archives of Barcelona. The kiln of Viladalls worked in Barcelona from the early 14th century to the end of the 15th century. Other kilns of glass could be found on the outskirts of the city or some were linked with some glaziers masters of Barcelona who worked here. We can see it in the kilns of Mallorca (1352, Badalona (1360, St. Pere de Bigues (1407-1513, St. Vicenç de Vallromanes (1439-84, and Montcada (1486- 89. A new kiln set up in Pla d’en Llull, Barcelona, in the 15th century, was the only one which had the Royal permission until the mid 16th century.

    Malgrat les disposicions municipals medievals sobre la prohibició d’installar forns de vidre dins les ciutats, alguns establiments van estar actius durant un temps considerable. La ciutat de Barcelona n’és un clar exemple. El present article se centra en les dades documentals trobades en els arxius barcelonins. A la ciutat de Barcelona, el forn de vidre de Viladalls va funcionar des de les primeries del segle XIV fins a finals del XV. Altres forns de vidre van néixer a l’entorn de la ciutat o vinculats a mestres vidriers procedents d’aquesta. És el cas dels forns de Mallorca (1352, Badalona (1360, St. Pere de Bigues (1407-1513, St. Vicenç de Vallromanes (1429-84 i Montcada (1486- 89. Al segle XV, un nou forn de vidre, situat al Pla d’en Llull, tingué l’exclusivitat en la producció de vidre a Barcelona, situació que es va mantenir fins a mitjan segle XVI.

  20. Dust-off

    OpenAIRE

    Maycroft, Neil; Cheang, Shu Lea

    2015-01-01

    The fan of a motherboard switches on and off intermittently. It blows household dust, removed from the inside of a computer carcass, into the air. The dust then settles onto the motherboard, to be blown off again. This continual movement of dust is contained in the piece. However, it should remind us that the ceaseless creation and motion of unconfined dust accompanies all stages of the e-waste journey.

  1. Physics of interstellar dust

    CERN Document Server

    Krugel, Endrik

    2002-01-01

    The dielectric permeability; How to evaluate grain cross sections; Very small and very big particles; Case studies of Mie calculus; Particle statistics; The radiative transition probability; Structure and composition of dust; Dust radiation; Dust and its environment; Polarization; Grain alignment; PAHs and spectral features of dust; Radiative transport; Diffuse matter in the Milky Way; Stars and their formation; Emission from young stars. Appendices Mathematical formulae; List of symbols.

  2. Grout cement. ; Grout cement to fill ground/grout cement to fill cracks. Chunyuyo cement. ; Jiban chunyuyo cement /hibiware chunyuyo cement

    Energy Technology Data Exchange (ETDEWEB)

    Okaue, H. (Nittetsu Cement Co. Ltd., Hokkaido (Japan))

    1991-09-01

    Ground grout cement is grouted into the ground under high pressure in high water ratio (100 to 1000%) in the form of milk differing from concrete in terms of the water-cement ratio. The grouted milk is governed by characteristics of the cement the milk itself possesses, resulting in variable grouting modes, which are divided in fracture grouting, permeation grouting and boundary grouting. Their applications include cutting off of water in dams, ground reinforcement, prevention of water gushing in tunnel excavation, natural ground reinforcement, improvement of sandy soil and prevention of its collapse, and stabilization of ground for urban civil engineering works such as subway, water supply and sewerage constructions. Grout cement to fill cracks in concrete structures is so grouted into cracks that the slurry fills up contiguous cracks to a certain level and goes upward while pushing out air or water existing in the cracks. The slurry filled into the cracks solidifies and hardens while being absorbed into the concrete, and finally integrates with the concrete. The grout cement is used to rework such concrete structures as dams, tunnels, and bridge bases. 6 figs., 4 tabs.

  3. Dust in the Universe

    Science.gov (United States)

    Hemenway, Mary Kay; Armosky, Brad J.

    2004-01-01

    Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even dust is getting its due, but not the dust everyone is familiar with. People seldom consider the dust in…

  4. Properties of Portland cement concretes containing pozzolanic admixtures

    Science.gov (United States)

    Simmons, D. D.; Pasko, T. J., Jr.; Jones, W. R.

    1981-04-01

    A laboratory comparison was made of the properties of a concrete containing no pozzolan with several mixtures containing pozzolans. Used were a natural pozzolan (Lassenite), two fly ashes of different fineness and low carbon and an amorphous silica fume dust from a metal-producing plant. One cement, one coarse crushed limestone aggregate, and one fine river aggregate were used. Replacing a faster reacting binder with a slower one, produced lower early strengths and adversely affected the properties which are highly dependent on strength. The measures of durability were greatly affected by the air contents and aging or treatment prior to exposure. The amorphous silica fume dust increased the early strengths of a fly ash mixture.

  5. 21 CFR 888.4200 - Cement dispenser.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027)...

  6. 山东古代烧瓷窑炉结构分析%An analysis of the Structure of Ancient Porcelain-firing Kilns in Shandong

    Institute of Scientific and Technical Information of China (English)

    秦彧

    2002-01-01

    The ancient porcelain-firing kilns of Shandong belonged to the system of dome kilns in North China. The present paper analyzes the 24 ancient kilns discovered in this region as to their shape in plan, internal structure and changes in fuel. It divides them into five types, sums up the features of each type, and points out their advantages and shortcomings, as well as technical changes. In the light of difference in fuel, the author assigned these types to two stages respectively. At the earlier stage, i.e. from Type I to type III, the fuel was firewood, and the third type of kiln constituted the mature form among the firewood kilns. At the later stage consisting of Types IV and V, coal was used as fuel, and Type V became the mature coal kiln for its proper structural proportion.

  7. Structural ceramics containing electric arc furnace dust.

    Science.gov (United States)

    Stathopoulos, V N; Papandreou, A; Kanellopoulou, D; Stournaras, C J

    2013-11-15

    In the present work the stabilization of electric arc furnace dust EAFD waste in structural clay ceramics was investigated. EAFD was collected over eleven production days. The collected waste was characterized for its chemical composition by Flame Atomic Absorption Spectroscopy. By powder XRD the crystal structure was studied while the fineness of the material was determined by a laser particle size analyzer. The environmental characterization was carried out by testing the dust according to EN12457 standard. Zn, Pb and Cd were leaching from the sample in significant amounts. The objective of this study is to investigate the stabilization properties of EAFD/clay ceramic structures and the potential of EAFD utilization into structural ceramics production (blocks). Mixtures of clay with 2.5% and 5% EAFD content were studied by TG/DTA, XRD, SEM, EN12457 standard leaching and mechanical properties as a function of firing temperature at 850, 900 and 950 °C. All laboratory facilities maintained 20 ± 1 °C. Consequently, a pilot-scale experiment was conducted with an addition of 2.5% and 5% EAFD to the extrusion mixture for the production of blocks. During blocks manufacturing, the firing step reached 950 °C in a tunnel kiln. Laboratory heating/cooling gradients were similar to pilot scale production firing. The as produced blocks were then subjected to quality control tests, i.e. dimensions according to EN772-17, water absorbance according to EN772-6, and compressive strength according to EN772-1 standard, in laboratory facilities certified under EN17025. The data obtained showed that the incorporation of EAFD resulted in an increase of mechanical strength. Moreover, leaching tests performed according to the Europeans standards on the EAFD-block samples showed that the quantities of heavy metals leached from crushed blocks were within the regulatory limits. Thus the EAFD-blocks can be regarded as material of no environmental concern.

  8. Cements containing by-product gypsum

    Energy Technology Data Exchange (ETDEWEB)

    Bensted, J. [University of Greenwich, London (United Kingdom). School of Biological and Chemical Sciences

    1995-12-31

    Chemical by-product gypsum can readily replace natural gypsum in Portland cements and in blended cements like Portland pfa cement and Portland blast furnace cement without technical detriment in many instances. Indeed, sometimes the technical performance of the cement can be enhanced. The hydration chemistry is often changed, in that where there is at least some retardation of setting, more AFT phase (ettringite) is formed during early hydration at the expense of calcium silicate hydrates. By-product gypsum can also replace natural gypsum in speciality products like calcium aluminate cement-Portland cement mixes for producing quick setting cements and in calcium sulphoaluminate-type expansive cements. However, by-products gypsum have proved to be less successful for utilization in API Classes of oilwell cements, because of the greater difficulty in obtaining batch-to-batch consistency in properties like thickening time and slurry rheology. 11 refs., 3 figs., 5 tabs.

  9. Leaching from waste incineration bottom ashes treated in a rotary kiln

    DEFF Research Database (Denmark)

    Hyks, Jiri; Nesterov, Igor; Mogensen, Erhardt

    2011-01-01

    Leaching from municipal solid waste incineration bottom ash treated in a rotary kiln was quantified using a combination of lab-scale leaching experiments and geochemical modelling. Thermal treatment in the rotary kiln had no significant effect on the leaching of Al, Ba, Ca, Mg, Si, Sr, Zn, sulfate...... their detection limits; no effects of the thermal treatment on leachability of these metals were observed. The leaching of Cl, dissolved organic carbon (DOC), Cu and Pb decreased by at least one order of magnitude after the thermal treatment. This could be explained by evaporation (Cl) and by a better burnout...... of organic matter which then limited metal–DOC complexation and mobility. At the same time, leaching of Mo and Cr appeared to increase by a factor of 4 and more than two orders of magnitude, respectively. The large changes in Cr leaching may be explained by decreases in Al reduction capacity after...

  10. Solar Kilns: Feasibility of Utilizing Solar Energy for Drying Lumber in Developing Countries,

    Science.gov (United States)

    1977-01-01

    evaluation of shelf type solar driers. Sol. Energy 16(2):81-88. N Selcuk, M. K. 1967. Final report of the solar fruit dryer . Cooperation Medi- terraneenne...at one dryer orientation (long axis north-south) from 30 percent to 10 percent moisture content. 49 Table 15.--Greenhouse-type solar kiln capacity...out the success or failure of some design features, construction details, and applications of solar dryers . Feasibility _; estimates concluded that

  11. Indications of the presence of middle neolithic pottery kilns at Magoula imvrou pigadi, SW Thessaly, Grecce:

    OpenAIRE

    Nina Kyparissi-Apostolika

    2012-01-01

    Red hot deposits were uncovered on the western edge of a Middle Neolithic settlement. With the extension of the excavation, a wide space of about 10m2, confined between two clay walls, very much affected by high temperatures, was uncovered. A number of vases almost totally complete after their preservation and a clay model of a kiln were unearthed. Additionally, clay remains of constructions were uncovered. The whole context suggests an area where pottery firing activities took place. The pos...

  12. Continuous pyrolysis of biomass feedstocks in rotary kiln convertors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Jr, H. H.; Kimzey, J. R.; Turpin, J. L.; MacCallum, R. N.

    1979-08-30

    The biomass research program at the University of Arkansas has developed three experimental projects or tasks for the attainment of its objectives. They are: (1) utilization of the existing full scale convertor for testing and data acquisition at Jonesboro, Arkansas; (2) development of a scale model rotary pyrolytic convertor (bench scale research kiln); and (3) development of analytical laboratory services for the analysis of feedstocks and products, and for basic pyrolytic process studies. The project at Jonesboro, Arkansas, which aimed at testing the Angelo convertor concept through heat and material balances over the available range of operations, could not completely achieve this objective because of the severe mechanical and structural deficiencies in the full scale convertor. A limited number of data have been taken in spite of the deficiencies of the machine. The scale model rotary kiln has been the most successful of the three projects. The kiln has been completed as planned and successfully operated with a number of feedstock materials. Good qualitative data have been obtained on conversion rate capacities, charcoal yields, and off gas combustion product temperatures. In all, about one hundred test runs were made in the scale model kiln. About 90% of the results expected were attained. The laboratory services project was designed to provide analytical testing for the other two projects and to do basic studies in biomass material conversion processes. The project delivered the testing services, but was severely restricted in the area of basic studies because of the failure of the main instrument, the gas chromatograph, to operate successfully. In all it is estimated that this project attained about 80% of its expected goals.

  13. Toxicity of lunar dust

    CERN Document Server

    Linnarsson, Dag; Fubini, Bice; Gerde, Per; Karlsson, Lars L; Loftus, David J; Prisk, G Kim; Staufer, Urs; Tranfield, Erin M; van Westrenen, Wim

    2012-01-01

    The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of substantial research efforts, lunar dust properties, and therefore lunar dust toxicity may differ substantially. In this contribution, past and ongoing work on dust toxicity is reviewed, and major knowledge gaps that prevent an accurate assessment of lunar dust toxicity are identified. Finally, a range of studies using ground-based, low-gravity, and in situ measurements is recommended to address the identified knowledge gaps. Because none of the curated lunar samples exist in a pristine state that preserves the surface reactive chemical aspects thought to be present on the lunar surface, studies using this material carry with them considerable uncertainty in terms of fidelity. As a consequence, in situ data on lunar dust...

  14. Air pollution tolerance index of plants around brick kilns in Rawalpindi, Pakistan.

    Science.gov (United States)

    Achakzai, Khanoranga; Khalid, Sofia; Adrees, Muhammad; Bibi, Aasma; Ali, Shafaqat; Nawaz, Rab; Rizwan, Muhammad

    2017-04-01

    In any contaminated environment, the sensitive plant species can serve as bio-indicator of air pollution while tolerant plant species can act as a sink for air pollutants. Air pollution tolerance index (APTI) is an important tool to screen out plants based on their tolerance or sensitivity level to different air pollutants. The present study was aimed to identify the sensitive and tolerant plant species in the vicinity of brick kilns in the Rawalpindi city. To determine the susceptibility level of the selected plant species, four biochemical parameters, ascorbic acid, total chlorophyll content, relative water content and pH of leaf extract, were assessed and APTI was calculated. Plant sampling was carried out with increasing distance of 100, 300 and 500 m around three brick kiln sites and APTI values were calculated by following the standard methods. The results of the study revealed that among nine studied plant species, Calotropis procera (APTI = 20.05) and Althernanthera pungens (APTI = 17.13) were found to be the most tolerant species, whereas Malva neglecta (APTI = 8.83) was found to be the most sensitive species. Inconsistent trend of variations was seen in the APTI values at each site. The present study suggested that the most tolerant species, C. procera and A. pungens, could be grown in the vicinity of such pollution sources as a remedial measure of brick kiln pollution.

  15. Magnesium substitution in brushite cements.

    Science.gov (United States)

    Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López

    2013-01-01

    The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.

  16. Portland cement-blast furnace slag blends in oilwell cementing applications

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, D.T.; DiLullo, G.; Hibbeler, J. [and others

    1995-12-31

    Recent investigations of blast furnace slag cementing technologies. have been expanded to include Portland cement/blast furnace slag blends. Mixtures of Portland cement and blast furnace slag, while having a long history of use in the construction industry, have not been used extensively in oilwell cementing applications. Test results indicate that blending blast furnace slag with Portland cement produces a high quality well cementing material. Presented are the design guidelines and laboratory test data relative to mixtures of blast furnace slag and Portland cements. Case histories delineating the use of blast furnace slag - Portland cement blends infield applications are also included.

  17. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-03-01

    Full Text Available In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone, calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

  18. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  19. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  20. Study the air pollution due to Dorud Cement Plant (in Iran

    Directory of Open Access Journals (Sweden)

    Vahid Mokhtari

    2016-09-01

    Full Text Available Cement industry is one of the most important industries in the country. Dorud Cement Plant is one of the largest and oldest Iran's cement factories, which is working in the center of the city of Dorud. In this study, aimed to investigate air pollution resulting from Dorud cement plant, the parameters of CO, CO2, O2, NO, NO2, NOx, SO2, dry dust particles, particles weight and environmental particulates of PM10 and PM2.5 were measured with conventional methods of measuring emissions from industrial chimneys and by using automatic measuring equipment, and the rates of emissions from the chimneys of the plant were calculated during a working year. These measurements were made over three months, from February 20, 2015 to May 21, 2015, at 3 stations of Link1-k1, Link2-k1 and Link3-k1, which are the chimneys of the three-lines of the plant. It was found in this study that the chimney No. 3 enters the maximum contaminant into the environment. The results also showed that based on the standards defined for the cement industry, Dorud cement plant meets the relative optimal conditions in terms of comparing performance with the standards, and the emissions from the factory are less than the enacted standards for this industry. Also, the preventive measures and equipment for reducing emissions established in this industrial unit have a relative utility. In this study, the factors including type of raw materials used, old production lines and old factory equipment, type of producing cement and proximity to the city were determined as main reasons for the emissions produced by this industry. Also, some management solutions such as the use of environment designing inside the manufacturing process of the plant and outside the plant, using flame-reducing, construction of a new phase and relocating the plant were suggested to reduce emissions from Dorud cement plants.

  1. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.”...

  2. Cementation of Loose Sand Particles based on Bio-cement

    Institute of Scientific and Technical Information of China (English)

    RONG Hui; QIAN Chunxiang

    2014-01-01

    Loose sand particles could be cemented to sandstone by bio-cement (microbial induced magnesium carbonate). The bio-sandstone was firstly prepared, and then the compressive strength and the porosity of the sandstone cemented by microbial induced magnesium carbonate were tested to characterize the cementation effectiveness. In addition, the formed mineral composition and the microstructure of bio-sandstone were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The experimental results show that the feasibility of binding loose sand particles using microbial induced magnesium carbonate precipitation is available and the acquired compressive strength of bio-sandstone can be excellent at certain ages. Moreover, the compressive strength and the porosity could be improved with the increase of microbial induced magnesium carbonate content. XRD results indicate that the morphology of magnesium carbonate induced by microbe appears as needles and SEM results show that the cementation of loose sand particles to sandstone mainly relies on the microbial induced formation of magnesium carbonate precipitation around individual particles and at particle-particle contacts.

  3. Operational Dust Prediction

    Science.gov (United States)

    Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; Jones, Luke; Lu, Sarah; Menut, Laurent; Morcrette, Jean-Jacques; Mulcahy, Jane; Nickovic, Slobodan; Garcia-Pando, Carlos P.; Reid, Jeffrey S.; Sekiyama, Thomas T.; Tanaka, Taichu Y.; Terradellas, Enric; Westphal, Douglas L.; Zhang, Xiao-Ye; Zhou, Chun-Hong

    2014-01-01

    Over the last few years, numerical prediction of dust aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. Dust prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to dust. Another limiting factor is the paucity of suitable dust observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of dust with examples from systems that are currently providing dust forecasts in near real-time or are part of international efforts to establish daily provision of dust forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of dust prediction activities and a historical perspective. Assimilation and evaluation aspects in dust prediction are also discussed.

  4. Transverse flow of cohesive powders in rotating kilns: experimental study and modeling; Ecoulement transversal de poudres cohesives en four tournant: etude experimentale et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Debacq, M.; Patisson, F.; Ablitzer, D. [Ecoles des Mines de Nancy, Lab. de Science et Genie des Materiaux Metalliques, UMR 7584, 54 - Nancy (France); Houzelot, J.L. [Ecole Nationale Superieure des Industries Chimiques (ENSIC), Lab. des Sciences du Genie Chimique, UPR 6811, 54 - Villers-les-Nancy (France); Feugier, A. [Societe Franco-Belge de Fabrication Combustibles, F.B.F.C., Dir. Technique, 26 - Romans (France); Hartmann, D. [Cogema, 26 - Pierrelatte (France)

    2001-07-01

    The transverse flow of cohesive powders of uranium in a rotating kiln equipped with raising levers has been studied experimentally at ambient temperature and at the temperatures of the process. The simple laws obtained have permitted to calculate the average distribution of the powder in a straight section of the kiln. (J.S.)

  5. Stone dusting process advance

    Energy Technology Data Exchange (ETDEWEB)

    Matt Ryan; David Humphreys [Mining Attachments (Qld.) Pty Ltd. (Australia)

    2009-01-15

    The coal mining industry has, for many years, used dry stone dust or calcium carbonate (CaCO{sub 3}) in the prevention of the propagation of coal dust explosions throughout their underground mines in Australia. In the last decade wet stone dusting has been introduced. This is where stone dust and water are mixed together to form a paste like slurry. This mixture is pumped and sprayed on to the underground roadway surfaces. This method solved the contamination of the intake airways but brought with it a new problem known as 'caking'. Caking is the hardened layer that is formed as the stone dust slurry dries. It was proven that this hardened layer compromises the dispersal characteristics of the stone dust and therefore its ability to suppress a coal dust explosion. This project set out to prove a specially formulated, non toxic slurry additive and process that could overcome the caking effect. The slurry additive process combines dry stone dust with water to form a slurry. The slurry is then treated with the additive and compressed air to create a highly vesicular foam like stone dusted surface. The initial testing on a range of additives and the effectiveness in minimising the caking effect of wet dusting were performed at Applied Chemical's research laboratory in Melbourne, Victoria and independently tested at the SGS laboratory in Paget, Queensland. The results from these tests provided the platform to conduct full scale spraying trials at the Queensland Mines Rescue Station and Caledon Coal's Cook Colliery, Blackwater. The project moved into the final stage of completion with the collection of data. The intent was to compare the slurry additive process to dry stone dusting in full-scale methane explosions at the CSIR Kloppersbos explosion facility in Kloppersbos, South Africa.

  6. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  7. 76 FR 76760 - Gray Portland Cement and Cement Clinker From Japan

    Science.gov (United States)

    2011-12-08

    ... Portland Cement and Cement Clinker From Japan Determination On the basis of the record \\1\\ developed in the... antidumping duty order on gray Portland cement and cement clinker from Japan would be likely to lead to... the Commission are contained in USITC Publication 4281 (December 2011), entitled Gray Portland...

  8. Antibacterial potential of contemporary dental luting cements.

    Science.gov (United States)

    Daugela, Povilas; Oziunas, Rimantas; Zekonis, Gediminas

    2008-01-01

    The aims of this investigation were to evaluate the antibacterial activities of different types of dental luting cements and to compare antibacterial action during and after setting. Agar diffusion testing was used to evaluate the antibacterial properties of seven types of dental luting cements (glass ionomer cements (GICs), resin modified GICs, resin composite, zinc oxide eugenol, zinc oxide non-eugenol, zinc phosphate, zinc polycarboxylate cements) on Streptococcus mutans bacteria. Instantly mixed zinc phosphate cements showed the strongest antibacterial activity in contrast to the non-eugenol, eugenol and resin cements that did not show any antibacterial effects. Non-hardened glass ionomer, resin modified and zinc polycarboxylate cements exhibited moderate antibacterial action. Hardened cements showed weaker antibacterial activities, than those ones applied right after mixing.

  9. Freezing resistance of high iron phoasphoaluminate cement

    Science.gov (United States)

    Zhang, S. X.; Lu, L. C.; Wang, S. D.; Zhao, P. Q.; Gong, C. C.

    2017-03-01

    The influence of freeze-thaw cycle on the mechanical properties of high iron phoasphoaluminate cement was investigated in the present study. The visual examination was conducted to evaluate the surface damage. The deterioration considering the weight loss, modulus loss of relative dynamic elastic and strength loss of mortar were also investigated. The morphology of hydration products were analysed by SEM. Compared with ordinary Portland cement and sulphoaluminate cement, the frost resistance of high iron phosphoraluminate cement is better. Hydration products of high iron phoasphoaluminate cement contain sheet crystals, and a lot of gel form a dense three-dimensional network structure, which results in a lower porosity. Different from ordinary Portland cement, the hydration product of high iron phoasphoaluminate cement does not contain Ca(OH)2, and low alkalinity reduces its osmotic pressure. The lower porosity and osmotic pressure are the two main reasons which causes in the higher frost resistance of high iron phoasphoaluminate cement.

  10. Discussion on the Technical of Total Nitrogen Removal in Cement Industry%水泥行业脱硝工艺技术的探讨

    Institute of Scientific and Technical Information of China (English)

    曾佳敏; 邓燕琳

    2012-01-01

    "十二五"期间,国家将氮氧化物列为大气污染物总量控制约束性指标。其中,水泥行业是氮氧化物减排的重点领域之一,新型干法水泥窑要进行低氮燃烧技术改造,新建水泥生产线要安装效率不低于60%的脱硝设施。文章根据目前水泥行业现状,探讨应相应匹配的脱硝工艺技术。%The "12th Five-Year Plan",the state will nitrogen oxide as the total control of air pollutant binding targets.Among them,the cement industry is one of the key fields of nitrogen oxide emission,cement kiln to low nitrogen combustion technology,a new cement production line to install the efficiency of not less than 60 % of the DeNOx facility.According to the current situation of cement industry,the corresponding matching denitration technology.

  11. 76 FR 24519 - Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning...

    Science.gov (United States)

    2011-05-02

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United States... determine whether revocation of the antidumping duty order on gray portland cement and cement clinker...

  12. 76 FR 50252 - Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review...

    Science.gov (United States)

    2011-08-12

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United... cement and cement clinker from Japan would be likely to lead to continuation or recurrence of...

  13. Galactic dust properties

    Science.gov (United States)

    Paradis, D.

    2011-12-01

    Recent studies have shown evidence for variations in the dust emissivity law with temperature and wavelength. A recent dust emission model, called TLS model (for two-level systems), based on the description of the disordered internal structure of the amorphous dust grains has been developped to interpret observations in the far-infrared/submillimeter (FIR/submm) domain. A recent work focusing on the comparison between data of the diffuse interstellar medium seen by FIRAS-WMAP, as well as Archeops compact sources, with the TLS model allowed us to constrain the model parameters characterizing the general Galactic dust properties. Using the newly available Herschel/Hi-GAL data of the inner Galactic plane, we report a 500 μm emissivity excess in the peripheral parts of the Galactic plane, that can reach up to 20% of the emissivity. Results of the TLS modeling indicate significant changes in the dust properties from the central to peripheral parts of the Galactic plane.

  14. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  15. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns...

  16. Cementation in adhesive dentistry: the weakest link

    NARCIS (Netherlands)

    Jongsma, L.A.

    2012-01-01

    Het succesvol bevestigen van tandrestauraties is een belangrijke en veeleisende procedure. Met behulp van cement wordt het restauratiemateriaal aan de tandstructuur verbonden. Op die manier worden twee hechtvlakken gecreëerd: het raakvlak tussen tand en cement, en het raakvlak tussen cement en resta

  17. "宜兴窑"初论%A Discussion on Yixing Kilns

    Institute of Scientific and Technical Information of China (English)

    贺云翱

    2015-01-01

    Yixing Kilns refer to the porcelain products as well as production facilities and techniques in Yixing area from the pre-Qin period through the Qing dynasty and even the contemporary time. The origin of Yixing Kilns may be dated to the Zhou times featuring primitive porcelains and patterned hard potteries. With the development in the Eastern Han through the Six Dynasties and the Tang, kilns in Yixing were capa-ble of celadon production although potteries were also manufactured. When it came to the Song, Yuan and Ming dynasties, Yixing Kilns gradually formed their production strength in pottery manufacture, from which, two major variety–the unglazed"purple clay craftsmanship"and the color-glazed"Jun pottery craftsman-ship"–were developed. In modern time, craftsmanship in celadon, purple clay and Jun pottery production receive revitalization while purple clay potteries enjoy the most prosperity.%"宜兴窑"是江苏乃至中国重要的陶瓷业窑口,其所指应是宜兴地区内从先秦一直到清代乃至当代所存在的陶瓷生产工艺及产品系统."宜兴窑"的时代上限大约在先秦两周前后,以原始瓷和印纹硬陶为特色;发展到东汉时期到六朝、唐宋进入到较为成熟的青瓷系统,同时也存在陶器制作;进入到宋元明时期,逐渐形成以陶器为特色的体系,在陶器中又生长出素身素面的"紫砂陶工艺系统"和彩釉装饰的"均陶工艺系统";发展到现代,传统的青瓷、紫砂陶、均陶等工艺系统都得到了传承和复兴,其中紫砂一脉更是大放异彩.

  18. PURIFICATION OF LIME KILN GAS%石灰窑气的净化

    Institute of Scientific and Technical Information of China (English)

    蒋如铁

    2001-01-01

    论述了影响石灰窑气除CO2外其它物质含量的工艺因素。分析了窑气净化的方式及干扰窑气净化的因素,并讨论了净化应注意的其它问题。%The effects of impurities content on the CO2 content in limekiln gas described.The ways and interfering factors of kiln gas purification are analysed, and other notable problems of purification are also discussed.

  19. Ceramic kilns with improved environmental protection. Umwelttechnische Verbesserungen bei Keramik-Brennoefen

    Energy Technology Data Exchange (ETDEWEB)

    Sladek, R. (Riedhammer GmbH und Co. KG, Nuernberg (Germany))

    1994-09-01

    Modern materials have made a decisive contribution to energy saving during firing processes. This paper surveys the different types of kiln linings currently available. The contaminants - in particular fluorine and hydrocarbons - can be neutralized with dry sorption plants and purpose-built post-combustion systems. These systems are also presented. A further section deals comprehensively with the subject of ceramic fibres and their effect on the human body. Their advantage is that they do not split and fan out like asbestos fibres, but break up into sections, so that only small fractions can become harmful. The legally permissible fibre exposure limits are also given. (orig.)

  20. Charcoal kiln sites, associated landscape attributes and historic forest conditions: DTM-based investigations in Hesse (Germany

    Directory of Open Access Journals (Sweden)

    Marcus Schmidt

    2016-03-01

    Full Text Available Background: An examination of the distribution of ancient charcoal kiln sites in the forest landscape seems to be worthwhile, since general trends in the selection of suitable kiln site locations in the past might become obvious. In this way forest landscape elements with a more intense usage by charcoal burning can be identified. By doing this, we can expect to gain information on the former condition and tree species composition of woodland. Investigations on the spatial distribution of charcoal kiln sites in relation to landscape attributes are sparse, however, probably due to the high on-site mapping effort. The outstanding suitability of LiDAR-derived digital terrain models (DTMs for the detection of charcoal kiln sites has been recently proved. Hence, DTM-based surveys of charcoal kiln sites represent a promising attempt to fill this research gap. Methods: Based on DTM-based surveys, we analyzed the spatial distribution of charcoal kiln sites in two forest landscapes in the German federal state of Hesse: Reinhardswald and Kellerwald-Edersee National Park. In doing so, we considered the landscape attibutes "tree species composition", “water supply status”, “nutrient supply status”, “soil complex classes”, “altitude”, “exposition”, and “inclination”. Results: We found that charcoal kiln sites were established preferably on hillside locations that provided optimal growing and regeneration conditions for European beech (Fagus sylvatica due to their acidic brown soils and sufficient water supply. These results are in line with instructions for the selection of appropriate kiln site locations, found in literature from the 18th to the 19th century. Conclusions: We conclude that there were well-stocked, beech-dominated deciduous forest stands in northern Hesse before 1800, particularly at poorly accessible hillside locations. These large stocks of beech wood were utilized by the governments of the different Hessian

  1. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  2. Early Implementation of Large Scale Carbon Dioxide Removal Projects through the Cement Industry

    Science.gov (United States)

    Zeman, F. S.

    2014-12-01

    The development of large-scale carbon dioxide reduction projects requires high purity CO2and a reactive cation source. A project seeking to provide both of these requirements will likely face cost barriers with current carbon prices. The cement industry is a suitable early implementation site for such projects by virtue of the properties of its exhaust gases and those of waste concrete. Cement plants are the second largest source of industrial CO2 emissions, globally. It is also the second largest commodity after water, has no ready substitute and is literally the foundation of society. Finally, half of the CO2 emissions originate from process reactions rather than fossil fuel combustion resulting in higher flue gas CO2concentrations. These properties, with the co-benefits of oxygen combustion, create a favorable environment for spatially suitable projects. Oxygen combustion involves substituting produced oxygen for air in a combustion reaction. The absence of gaseous N2 necessitates the recirculation of exhaust gases to maintain kiln temperatures, which increase the CO2 concentrations from 28% to 80% or more. Gas exit temperatures are also elevated (>300oC) and can reach higher temperatures if the multi stage pre-heater towers, that recover heat, are re-designed in light of FGR. A ready source of cations can be found in waste concrete, a by-product of construction and demolition activities. These wastes can be processed to remove cations and then reacted with atmospheric CO2 to produce carbonate minerals. While not carbon negative, they represent a demonstration opportunity for binding atmospheric CO2while producing a saleable product (precipitated calcium carbonate). This paper will present experimental results on PCC production from waste concrete along with modeling results for oxygen combustion at cement facilities. The results will be presented with a view to mineral sequestration process design and implementation.

  3. Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters

    Directory of Open Access Journals (Sweden)

    S. Chowdhury

    2015-11-01

    Full Text Available In this study, Wood Ash (WA prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45 and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20% including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM, strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

  4. Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters.

    Science.gov (United States)

    Chowdhury, S; Maniar, A; Suganya, O M

    2015-11-01

    In this study, Wood Ash (WA) prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength) of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45) and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20%) including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM), strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

  5. 富氧燃烧在水泥生产中的应用%The Application of Oxygen-enriched Combustion to the Cement Production

    Institute of Scientific and Technical Information of China (English)

    杨志芳; 卿山; 王华; 邓文龙; 魏可

    2013-01-01

    随着全球能源危机的加剧,燃料价格的不断上涨及环保要求的不断提高,企业的生产成本越来越高,节能降耗和保护环境是每个企业发展的重要问题.富氧燃烧作为较新的燃烧技术在节能和减排方面的优良性能,在工业炉窑方面的应用得到了大力的推广.本试验在国内某4000 t/d水泥回转窑线上进行,根据富氧助燃试验所测定的数据,确定水泥回转窑在富氧生产工况下主要参数的运行变化规律,为水泥建材行业的节能减排工作提供重要理论和实践依据.%With the global energy crisis intensifies,rising prices for the fuel and environmental protection requirements continue to increase,causing the production cost of enterprises is more and more high,save energy and protect environment are the most important problems in the development of each enterprise.Oxygen-enriched combustion as a new combustion technology in saving energy and emission as the excellent performance,application in industrial furnaces has been strong promotion.This experiment in a domestic 4000 t/d cement rotary kiln line,according to the oxygen-rich combustion test measured data,determining the cement rotary kiln in oxygen-rich production conditions of main parameters of running changes,as the cement building materials industry energy-saving emission reduction work to provide an important basis for theory and practice.

  6. Gasification of secondary fuels in a circulating fluidized bed for energetic use in cement production; Vergasung von Sekundaerbrennstoffen in der zirkulierenden Wirbelschicht zur energetischen Nutzung fuer die Zementherstellung

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, J.; Gafron, B. [Lurgi Umwelt GmbH, Frankfurt am Main (Germany); Scur, P.; Wirthwein, R. [Ruedersdorfer Zement GmbH (Germany)

    1998-09-01

    Ruedersforf cement factory was commissioned a century ago as one of the first in Germany. After the plant was taken over by Readymix AG, a comprehensive sanitation concept was carried through. The plant has a production capacity of 8000 t/d of cement clinkers which are produced in a new kiln with a capacity of 6000 t/d and two modernized kilns each with a capacity of 1000 t/d. Reduction of energy consumption was the main goal of modernisation, with fuel gas generation in a circulating fluidized bed as a key element. The unit provides 40 % of the energy consumed by the clinker production process and is also used for selective ash production up to 25 t/h. The ash is used as a raw material for cement production. (orig./SR) [Deutsch] Bereits vor 100 Jahren wurde eine der ersten Zementfabriken in Deutschland am Standort Ruedersdorf in Betrieb genommen. Zum Erhalt der Wettbewerbsfaehigkeit wurde nach der Uebernahme des Werkes Ruedersdorf durch die Readymix AG ein umfangreiches Sanierungskonzept in die Wege geleitet. Bei einer Produktionskapazitaet von ca. 8 000 t Klinker pro Tag werden eine neue Ofenanlage mit einer Kapazitaet von 6 000 t/Tag sowie 2 sanierte kleine Anlagen zu je 1000 t/Tag betrieben. In der neuen Ofenanlage werden alle Moeglichkeiten genutzt, den Energiebedarf fuer die Klinkerproduktion zu senken. Eine wesentliche neue innovative Komponente ist dabei eine Brenngaserzeugung in einer Zirkulierenden Wirbelschicht, ueber die im folgenden berichtet werden soll. Die Anlage kann bis zu 40% des Energiebedarfes des Zementprozesses liefern. Weiterhin wird mit der ZWS eine gezielte Ascheproduktion, bis zu 25 t/h, betrieben. Diese Aschen sind Teil der Rohstoffrezeptur an der Rohmuehle. (orig./SR)

  7. Thoughts on the Current Cement Industry Development

    Institute of Scientific and Technical Information of China (English)

    Gan Zhihe

    2003-01-01

    According to the analysis of cement capacity andits relations with macro economy running index, the mainreasons for the present rapid development of cement capacityare the rapid development of economy and the shot up ofwhole society fixed asset investment. According to the presentspeed of economy development, cement still enjoys a po-tential increase, So here has not been an overall excessivepopularity of cement industry. The best way to prevent lowlevel repeated construction is to promote the development ofnew dry- process cement as well as try to get rid of blindness.

  8. Thermodynamic analysis of the selective chlorination of electric arc furnace dust.

    Science.gov (United States)

    Pickles, C A

    2009-07-30

    The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

  9. Thermodynamic analysis of the selective chlorination of electric arc furnace dust

    Energy Technology Data Exchange (ETDEWEB)

    Pickles, C.A., E-mail: pickles-c@mine.queensu.ca [Department of Mining Engineering, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada)

    2009-07-30

    The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

  10. Production of cements from Illinois coal ash. Final technical report, September 1, 1995--August 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.C.; Bhatty, J.L.; Mishulovich, A.

    1997-05-01

    The objective of this program is to convert Illinois coal combustion residues, such as fly ash, bottom ash, and boiler slag, into novel cementitious materials for use in the construction industry. These residues are composed largely of SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, MgO, and CaO, which are also the major components of cement. Since the residues are used as an integral component of the cement and not just as additives to concrete, larger amounts of the residues can be utilized. The process uses submerged combustion to melt blends of coal combustion residues with lime, clay, and/or sand. The submerged combustion melter utilizes natural gas-oxidant firing directly into a molten bath to provide efficient melting of mineral-like materials. Use of this melter for cement production has many advantages over rotary kilns including very little, if any, grinding of the feed material, very low emissions, and compact size. During the first year of the program, samples of coal combustion residues were blended and mixed, as needed; with lime, clay, and/or sand to adjust the composition. Six mixtures, three with fly ash and three with bottom ash, were melted in a laboratory-scale furnace. The resultant products were used in mortar cubes and bars which were subjected to ASTM standard tests of cementitious properties. In the hydraulic activity test, mortar cubes were found to have a strength comparable to standard mortar cements. In the compressive strength test, mortar cubes were found to have strengths that exceeded ASTM blended cement performance specifications. In the ASR expansion test, mortar bars were subjected to alkali-silica reaction-induced expansion, which is a problem for siliceous aggregate-based concretes that are exposed to moisture. The mortar bars made with the products inhibited 85 to 97% of this expansion. These results show that residue-based products have an excellent potential as ASR-preventing additions in concretes.

  11. Conversion of low density polyethylene into petrochemical feedstocks using a continuous screw kiln reactor

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, D.P.; Aguado, J.; Escola, J.M. [ESCET, Rey Juan Carlos University, c/Tulipan s/n, 28933 Mostoles, Madrid (Spain); Garagorri, E. [Chemical Engineering Department, Complutense University of Madrid, Av. Complutense s/n, 28040 Madrid (Spain)

    2001-04-01

    Thermal and catalytic degradation of low-density polyethylene (LDPE) has been investigated using a screw kiln reactor provided with two zones of reaction temperature. Thermal degradation experiments carried out at different temperatures and screw speeds have shown that this continuous system is suitable for the LDPE degradation, product outputs up to c.a. 100 g/h being obtained. Compared to a conventional batch reactor, the screw kiln system leads to a lower formation of gaseous products, whereas overcracking of the heavy fractions is also reduced. These differences are probably originated by the intimate contact and the same residence times for all the product fractions that exist within the screw reactor, which is in contrast with the selective and fast withdrawal of volatile products taking place in the batch system. In the catalytic experiments, a mesoporous MCM-41 type aluminosilicate has been used as catalyst, being continuously fed to the screw reactor mixed with the raw plastic material. In these conditions, yields up to 80% towards hydrocarbons within the gasoline range (C{sub 5}-C{sub 12}) have been obtained. Moreover, high amounts of C{sub 7} and C{sub 8} hydrocarbons are present in the gasoline fractions, which is assigned to catalytic oligomerization reactions that selectively affect to C{sub 3} and C{sub 4} gaseous hydrocarbons.

  12. 焙烧短窑研制浅谈%Synopsis Discussing Manufacture of Short Calcining Kiln

    Institute of Scientific and Technical Information of China (English)

    段玉新

    2014-01-01

    介绍了红土镍矿资源现状、红土镍矿的处理工艺方法及焙烧短窑的研发背景。焙烧短窑作为新兴的环保设备,具有螺旋往返快速均匀给料、液压倾翻排料、还原时间可控、热效率高、利用率高的特点,在稀有贵重金属冶炼方面具有非常广泛的应用前景。%T his article briefly introduces present situation of nickeliferous laterites , the processes for pro-ducing nicheliferous laterites and background of inventing short calcining kiln . It is the newly arisen envi-ronmental protection equipments , It has the characteristics of quickly and evenly feeding , discharging with hydraulic pressure , controling deoxidize time ,supernal thermal efficiency and widely using . The short cal-cining kiln have widely using in smelting of the rare noble metal .

  13. The Concept, Design and Performance of a Novel Rotary Kiln Type Air-Staged Biomass Gasifier

    Directory of Open Access Journals (Sweden)

    Huiyuan Shi

    2016-01-01

    Full Text Available Tar formation is the main bottleneck for biomass gasification technology. A novel rotary kiln type biomass gasification process was proposed. The concept design was based on air staging and process separation. This concept was demonstrated on a pilot scale rotary kiln reactor under ambient pressure and autothermic conditions. The pilot scale gasifier was divided into three different reaction regions, which were oxidative degradation, partial oxidation and char gasification. A series of tests was conducted to investigate the effect of key parameters. The results indicate that under optimum operating conditions, a fuel gas with high heat value of about 5500 kJ/Nm3 and gas production rate of 2.32 Nm3/kg could be produced. Tar concentration in the fuel gas could be reduced to 108 mg/Nm3 (at the gasifier outlet and 38 mg/Nm3 (after gas conditioning. The cold gas efficiency and carbon conversion rate reached 75% and 78%, respectively. The performance of this gasification system shows considerable potential for implementation in distributed electricity and heat supply projects.

  14. CFD prediction of physical field for multi-air channel pulverized coal burner in rotary kiln

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5 m in diameter, 90 m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results.The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.

  15. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used...... as the sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone...... that raw meal could be used as a sorbent for the easy integration of the carbonate looping process into the cement pyro process for reducing CO2 emissions from the cement production process....

  16. Understanding cement mechanical behavior in SAGD wells

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J.; Zahacy, T. A. [C-FER Technologies (Canada)

    2011-07-01

    In the heavy oil industry, the steam assisted gravity drainage process is often used to enhance oil recovery but it can cause cracks in the cement sheath. These cracks are the result of high steam temperatures and thermal expansion. In order to mitigate this risk, improved well designs are required. The aim of this paper is to present the mechanical behavior of the cement sheath during the heating phase. An analysis of the impact of design and operating parameters was conducted through thermal hydraulic and thermal mechanical analyses to assess cement integrity. These analyses were then performed on an example of an SAGD project in the southern part of the Athabasca oilsands region to assess the performance of the cement sheath. Results showed that potential damage to the cement can be reduced by slow heating and a lower Young's modulus cement blend. This paper makes recommendations for optimizing cement design in thermal recovery wells.

  17. Biomonitoring of Air Pollution by Magnetic Measurements of Native and Transplanted Lichens; Two Case Studies Around Cement Plants

    Science.gov (United States)

    Winkler, A.; Paoli, L.; Kodnik, D.; Candotto Carniel, F.; Guttová, A.; Loppi, S.; Sagnotti, L.; Tretiach, M.

    2015-12-01

    A cement plant is a source of dust pollution and lichens are suitable biomonitors of the impact of airborne pollutants released during cement production. We investigated the magnetic and chemical properties of lichens exposed around two cement plants, located in SW Slovakia and in NE Italy, respectively. We characterized the magnetic properties of the lichen Evernia prunastri exposed for 180 days at selected sites around a Slovak cement plant in order to define the magnetic mineralogy and test the correlations between the concentration-dependent magnetic parameters and the content of heavy metals and crustal elements in the thalli. In addition, we compared the magnetic properties of the transplants to those carried by native thalli of the lichen Xanthoria parietina and neighboring soils, barks and rocks. The data indicated a substantial homogenous magnetic mineralogy, with the exception of a sample collected from a basalt quarry. The transplants showed an excellent correlation between the saturation remanent magnetization (Mrs) and the concentration of Fe; the concentrations of the elements linked to cement production also correlated to Mrs values, apart from the basalt quarry sample. In the second context, we characterized the magnetic properties of the lichen Pseudevernia furfuracea transplanted near a cement plant in NE Italy. The transplants were exposed for 2 months in 40 sites distributed in surrounding rural, urban and industrial areas. In this case, the agreement between the magnetic and elemental datasets pointed out a modest environmental impact of the cement plant compared to the neighboring industrial activities, which resulted in significantly higher values of the concentration-dependent magnetic parameters. Magnetic analyses on lichens can expand the dataset of passive dust collectors in environmental magnetism, with the advantage, for the transplants, of precisely knowing the exposure time and the initial conditions.

  18. Language Select Language Article Tools Print this article Indexing metadata How to cite item Email this article Email the author Information For Authors For Librarians p-ISSN: 2088-4842 e-ISSN: 2442-8795 Home > Vol 15, No 1 > Putri Penjadwalan Cement Mill Berbasis Minimasi Faktor Klinker dalam Proses Pembilasan dan Impor Klinker

    Directory of Open Access Journals (Sweden)

    Nilda Tri Putri

    2016-04-01

    Full Text Available PT Semen Padang is one of the cement companies in indonesia. Cement production influenced by the number of demand, raw materials and the number of available machine. The number of demand increases with a corporate capacity which keep the company had to set an optimal production schedule. Scheduling production should be followed by the availability of raw materials (clinker. The number of clinker required influenced by the number of demands and clinker elapsed to the flushing process. Flushing process happen if the transition products produced from Non OPC to a product OPC, for one flushing process causes clinker consumption 7% more that the existing capacity decreases. Deficient in capacity covered by importing clinker which causes high cost production. So, it necessary to make cement mill schedule by minimize flushing process, so clinker that will be used become optimized. Steps that will be done in this study began with the survey system, identify problems, and data collection. Data collected are machine cement mill and kiln capacity, demands, and flushing process. Then designed a formulation model that is minimize clinker factor and the number of clinker imports needed, so that obtained scheduling machine cement mill to produce OPC and Non OPC. Results obtained by reducing the number of flushing process because the cement mill designed to producing one type of product per day, so the flushing process could happen if there is transition cement production Non OPC on the day-i to cement OPC on the day i+1. Cement OPC produced by indarung II, III, and V. Indarung IV only produced cement Non OPC, so the flushing process happened in Indarung II, III, and V.

  19. Some durability aspects of hybrid alkaline cements

    Directory of Open Access Journals (Sweden)

    Donatello S.

    2014-04-01

    Full Text Available Blended cements that contain a high content of fly ash and a low content of Portland cement typically suffer from low early strength development and long setting times. Recently, one method of overcoming these problems has been to use an alkali activator to enhance the reactivity of fly ash particles at early ages. Such cements can be grouped under the generic term “hybrid alkaline cements”, where both cement clinker and fly ash, encouraged by the presence of alkalis, are expected to contribute to cementitious gel formation. The work presented here examines some of the durability aspects of high fly ash content hybrid alkaline cement. Specifically, the aspects investigated were: exposure at high temperatures (up to 1000°C, resistance to immersion in aggressive solutions and susceptibility to the alkali aggregate reaction. All tests were repeated with a commercially available sulfate resistant Portland cement for comparison. When exposed to high temperatures, the hybrid alkaline cement showed strikingly different behaviour compared to the control Portland cement, showing fewer micro-cracks and maintaining residual compressive strengths at least equal to original strengths. Beyond 700°C, the hybrid alkaline cement began to sinter, which resulted in shrinkage of around 5% and a 100% increase in residual compressive strengths. No such sintering event was noted in the control Portland cement, which showed a drastic loss in residual compressive strengths upon heating. In immersion tests, the hybrid alkaline cement possessed excellent resistance to sulfate and seawater attack, similar to the control sulfate resistant cement. Both cements were however severely degraded by immersion in 0.1M HCl for 90 days. Both binders complied with the accelerated alkali-aggregate test but when this test was extended, the hybrid alkaline binder showed much greater dimensional stability. Possible reasons for the differences in durability behaviour in both cements

  20. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting....... Consequently, a combination of carburizing and oxidizing conditions has a strong mutual catalyzing effect on the metal dusting corrosion....

  1. Structural ceramics containing electric arc furnace dust

    Energy Technology Data Exchange (ETDEWEB)

    Stathopoulos, V.N., E-mail: vasta@teihal.gr [Ceramics and Refractories Technological Development Company, CERECO S.A., 72nd km Athens Lamia National Road, P.O. Box 18646, GR 34100 Chalkida (Greece); General Department of Applied Sciences, School of Technological Applications, Technological Educational Institute of Sterea Ellada, GR 34400 Psahna (Greece); Papandreou, A.; Kanellopoulou, D.; Stournaras, C.J. [Ceramics and Refractories Technological Development Company, CERECO S.A., 72nd km Athens Lamia National Road, P.O. Box 18646, GR 34100 Chalkida (Greece)

    2013-11-15

    Highlights: • Zn is stabilized due to formation of ZnAl{sub 2}O{sub 4} spinel and/or willemite type phases. • EAFD/clay fired mixtures exhibit improved mechanical properties. • Hollow bricks were successfully fabricated from the mixtures studied. • Laboratory articles and scaled up bricks found as environmentally inert materials. -- Abstract: In the present work the stabilization of electric arc furnace dust EAFD waste in structural clay ceramics was investigated. EAFD was collected over eleven production days. The collected waste was characterized for its chemical composition by Flame Atomic Absorption Spectroscopy. By powder XRD the crystal structure was studied while the fineness of the material was determined by a laser particle size analyzer. The environmental characterization was carried out by testing the dust according to EN12457 standard. Zn, Pb and Cd were leaching from the sample in significant amounts. The objective of this study is to investigate the stabilization properties of EAFD/clay ceramic structures and the potential of EAFD utilization into structural ceramics production (blocks). Mixtures of clay with 2.5% and 5% EAFD content were studied by TG/DTA, XRD, SEM, EN12457 standard leaching and mechanical properties as a function of firing temperature at 850, 900 and 950 °C. All laboratory facilities maintained 20 ± 1 °C. Consequently, a pilot-scale experiment was conducted with an addition of 2.5% and 5% EAFD to the extrusion mixture for the production of blocks. During blocks manufacturing, the firing step reached 950 °C in a tunnel kiln. Laboratory heating/cooling gradients were similar to pilot scale production firing. The as produced blocks were then subjected to quality control tests, i.e. dimensions according to EN772-17, water absorbance according to EN772-6, and compressive strength according to EN772-1 standard, in laboratory facilities certified under EN17025. The data obtained showed that the incorporation of EAFD resulted in

  2. Nano Dust Analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a new highly sensitive instrument to confirm the existence of the so-called nano-dust particles, characterize their impact parameters, and...

  3. Composite circumstellar dust grains

    Science.gov (United States)

    Gupta, Ranjan; Vaidya, Dipak B.; Dutta, Rajeshwari

    2016-10-01

    We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5-25 μm. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18 μm. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-type and asymptotic giant branch stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes, shape, composition and dust temperature.

  4. Composite Circumstellar Dust Grains

    CERN Document Server

    Gupta, Ranjan; Dutta, Rajeshwari

    2016-01-01

    We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5--25$\\rm \\mu m$. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18$\\rm \\mu m$. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-Type \\& AGB stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes; shape; composition and dust temperature.

  5. Hydrogen fluoride effects on local mung bean and maize cereal crops from peri-urban brick kilns in south asia

    NARCIS (Netherlands)

    Ahmad, M.N.; Ahmad, S.S.; Zia, A.; Iqbal, M.S.; Shah, H.; Mian, A.A.; Shah, R.U.

    2014-01-01

    Increased urbanisation throughout South Asia has increased the number and output of the brick kilns that typically surround major cities, but the environmental and health impacts of their atmospheric emissions are poorly understood in Pakistan. We report the negative effects of hydrogen fluoride (HF

  6. Gaseous pollutants from brick kiln industry decreased the growth, photosynthesis, and yield of wheat (Triticum aestivum L.).

    Science.gov (United States)

    Adrees, Muhammad; Ibrahim, Muhammad; Shah, Aamir Mehmood; Abbas, Farhat; Saleem, Farhan; Rizwan, Muhammad; Hina, Saadia; Jabeen, Fariha; Ali, Shafaqat

    2016-05-01

    Gaseous pollutant emissions from brick kiln industries deteriorate the current state of ambient air quality in Pakistan and worldwide. These gaseous pollutants affect the health of plants and may decrease plant growth and yield. A field experiment that was conducted to monitor the concentration of gaseous pollutants emitted mainly from brick kilns in the ambient air and associated impacts on the growth and physiological attributes of the two wheat (Triticum spp.) cultivars. Plants were grown at three sites, including control (Ayub Agriculture Research Institute, AARI), low pollution (LP) site (Small Estate Industry), and high pollution (HP) site (Sidar Bypass), of Faisalabad, Pakistan. Monitoring of ambient air pollution at experimental sites was carried out using the state-of-art ambient air analyzers. Plants were harvested after 120 days of germination and were analyzed for different growth attributes. Results showed that the hourly average concentration of gaseous air pollutants CO, NO2, SO2, and PM10 at HP site were significantly higher than the LP and control sites. Similarly, gaseous pollutants decreased plant height, straw and grain yield, photosynthesis and increased physical injury, and metal concentrations in the grains. However, wheat response toward gaseous pollutants did not differ between cultivars (Galaxy and 8173) studied. Overall, the results indicated that brick kiln emissions could reduce the performance of wheat grown in the soils around kilns and confirm the adverse impacts of pollutants on the growth, yield, and quality of the wheat.

  7. Brick Kiln Emissions Quantified with the Aerodyne Mobile Laboratory During the Short Lived Climate Forcing (SLCF) 2013 Campaign in Guanajuato Mexico

    Science.gov (United States)

    Fortner, E.; Knighton, W. B.; Herndon, S.; Roscioli, J. R.; Zavala, M.; Onasch, T. B.; Jayne, J. T.; Worsnop, D. R.; Kolb, C. E.; Molina, L. T.

    2013-12-01

    Brick kiln emissions are suspected to be a major source of atmospheric black carbon (BC) in developing countries; and black carbon's role as a short lived climate forcing (SLCF) pollutant is widely recognized. The SLCF-Mexico brick kiln study was conducted from 12-17 March 2013 in Mexico's Guanajuato state. Three different types of brick kilns were investigated (MK2, traditional, and traditional three tier) providing data on the effects of different kiln designs on particle and gas phase emissions. The BC and gaseous combustion emissions from these kilns were measured during both the fire stage and the subsequent smoldering stage with real-time instruments deployed on the Aerodyne Mobile Laboratory, and quantified utilizing flux tracer gases released adjacent to the brick kiln. This method allows examination of the brick kiln plume's evolution as it transits downwind from the source. Particulate measurements conducted by the mobile laboratory included the multi angle absorption photometer (MAAP) to measure black carbon mass, cavity attenuated phase shift (CAPSext) monitor to measure extinction and soot particle aerosol mass spectrometer (SP-AMS) measurements of black carbon. The SP-AMS instrument combines the ability to measure black carbon with the ability to determine the chemical composition of the other particulate matter (PM) components associated with black carbon particles. The variance of PM chemical composition will be examined as a function of burning stage and kiln type and compared to other black carbon PM sources. Gas phase exhaust species measured included CO, CO2, NOx, SO2, CH4, C2H6, as well as a variety of VOCs (acetonitrile, benzene etc.) measured with a PTR-MS instrument. All of these measurements will be examined to construct emission ratios evaluating how these vary with different kiln types and different firing conditions. The evolution of particulate matter and gas phase species as they transit away from the source will also be examined.

  8. Emissions and Char Quality of Flame-Curtain "Kon Tiki" Kilns for Farmer-Scale Charcoal/Biochar Production.

    Directory of Open Access Journals (Sweden)

    Gerard Cornelissen

    Full Text Available Pyrolysis of organic waste or woody materials yields charcoal, a stable carbonaceous product that can be used for cooking or mixed into soil, in the latter case often termed "biochar". Traditional kiln technologies for charcoal production are slow and without treatment of the pyrolysis gases, resulting in emissions of gases (mainly methane and carbon monoxide and aerosols that are both toxic and contribute to greenhouse gas emissions. In retort kilns pyrolysis gases are led back to a combustion chamber. This can reduce emissions substantially, but is costly and consumes a considerable amount of valuable ignition material such as wood during start-up. To overcome these problems, a novel type of technology, the Kon-Tiki flame curtain pyrolysis, is proposed. This technology combines the simplicity of the traditional kiln with the combustion of pyrolysis gases in the flame curtain (similar to retort kilns, also avoiding use of external fuel for start-up.A field study in Nepal using various feedstocks showed char yields of 22 ± 5% on a dry weight basis and 40 ± 11% on a C basis. Biochars with high C contents (76 ± 9%; n = 57, average surface areas (11 to 215 m2 g-1, low EPA16-PAHs (2.3 to 6.6 mg kg-1 and high CECs (43 to 217 cmolc/kg(average for all feedstocks, mainly woody shrubs were obtained, in compliance with the European Biochar Certificate (EBC.Mean emission factors for the flame curtain kilns were (g kg-1 biochar for all feedstocks; CO2 = 4300 ± 1700, CO = 54 ± 35, non-methane volatile organic compounds (NMVOC = 6 ± 3, CH4 = 30 ± 60, aerosols (PM10 = 11 ± 15, total products of incomplete combustion (PIC = 100 ± 83 and NOx = 0.4 ± 0.3. The flame curtain kilns emitted statistically significantly (p<0.05 lower amounts of CO, PIC and NOx than retort and traditional kilns, and higher amounts of CO2.With benefits such as high quality biochar, low emission, no need for start-up fuel, fast pyrolysis time and, importantly, easy and cheap

  9. Dust Versus Cosmic Acceleration

    CERN Document Server

    Aguirre, A N

    1999-01-01

    Two groups have recently discovered a statistically significant deviation in the fluxes of high-redshift type Ia supernovae from the predictions of a Friedmann model with zero cosmological constant. This letter argues that bright, dusty, starburst galaxies would preferentially eject a dust component with a shallower opacity curve (hence less reddening) and a higher opacity/mass than the observed galactic dust which is left behind. Such dust could cause the falloff in flux at high-z without violating constraints on reddening or metallicity. The specific model presented is of needle-like dust, which is expected from the theory of crystal growth and has been detected in samples of interstellar dust. Carbon needles with conservative properties can supply the necessary opacity, and would very likely be ejected from galaxies as required. The model is not subject to the arguments given in the literature against grey dust, but may be constrained by future data from supernova searches done at higher redshift, in clust...

  10. Prevalence and determinants of mucous membrane irritations in a community near a cement factory in Zambia: a cross sectional study.

    Science.gov (United States)

    Nkhama, Emmy; Ndhlovu, Micky; Dvonch, J Timothy; Siziya, Seter; Voyi, Kuku

    2015-01-16

    Exposure to cement dust has been associated with deleterious health effects in humans. This study investigated whether residing near a cement factory increases the risk of irritations to the mucous membranes of the eyes and respiratory system. A cross sectional study was conducted in Freedom Compound, a community bordering a cement factory in Chilanga, Zambia and a control community, Bauleni, located 18 km from the cement plant. A modified American Thoracic Society questionnaire was administered to 225 and 198 respondents aged 15-59 years from Freedom and Bauleni, respectively, to capture symptoms of the irritations. Respondents from Freedom Compound, were more likely to experience the irritations; adjusted ORs 2.50 (95% CI: 1.65, 3.79), 4.36 (95% CI (2.96, 6.55)) and 1.94 (95% CI (1.19, 3.18)) for eye, nose and sinus membrane irritations respectively. Cohort panel studies to determine associations of cement emissions to mucous membrane irritations and respiratory symptoms, coupled with field characterization of the exposure are needed to assess whether the excess prevalence of symptoms of mucous membrane irritations observed in Freedom compound are due to emissions from the cement factory.

  11. Survey of the Baihe Porcelain Kiln-site in Gongyi City,Henan%河南巩义市白河瓷窑遗址调查

    Institute of Scientific and Technical Information of China (English)

    郑州市文物考古研究所; 巩义市文物保护管理所

    2001-01-01

    In October and November of 1998, Zhengzhou Municipal Institute of Cultural Relics and Archaeology undertook a survey on the porcelain kiln site in the upper valley of the Baihe river, Gongyi City, Henan Province, and a great number of porcelain shards and kiln implements have been found. The findings are mainly from the Tang Dynasty, while some of them might have been the remains of the Sui and the Song Dynasties. The kiln site was famous for its white porcelain items and some of them were tributes to the Tang Emperors.

  12. Research of magnesium phosphosilicate cement

    Science.gov (United States)

    Ding, Zhu

    Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The goal of this research is to investigate the composition, reaction products, reaction mechanism, microstructure, properties, durability and applications of the MPSC. MPSC sets rapidly and has high early strength. It reacts better with solid industrial waste when compared to Portland cement. Many solid industrial wastes, such as fly ash, steel slag, coal gangue, red coal gangue, red mud, barium-bearing slag, copper slag, silica fume, and ground granulated blast furnace slag, have been used as the main component (40% by weight) in MPSC. The research has found that these aluminosilicate (or ironsilicate, or calciumsilicate) minerals with an amorphous or glass structure can enhance the performance of MPSC. The disorganized internal structure of amorphous materials may make it possess higher reactivity compared to the crystalline phases. Chemical reaction between phosphate and these minerals may form an amorphous gel, which is favorable to the cementing. Borax, boric acid and sodium tripolyphosphate have been used as retardants in the MPSC system. It is found that boric acid has a higher retarding effect on the setting of cement, than borax does. However, sodium polyphosphate accelerates the reaction of MPSC. The hydration of MPSC is exothermic reaction. The heat evolution may prompt hydrates formation, and shorten the setting process. Modern materials characterization techniques, XRD, DSC, TG-DTA FTIR, XPS, MAS-NMR, SEM, TEM, MIP, etc. were used to analyze the phase composition, micro morphology, and microstructure of hardened MPSC. The main hydration product

  13. Magnetic characteristics of industrial dust from different sources of emission: A case study of Poland

    Science.gov (United States)

    Szuszkiewicz, Marcin; Magiera, Tadeusz; Kapička, Aleš; Petrovský, Eduard; Grison, Hanna; Gołuchowska, Beata

    2015-05-01

    Dust emission and deposition in topsoil have negative effect on individual components of the ecosystem. In addition to routine geochemical analyses, magnetic measurements may provide useful complementary information related to the type, concentration and grain-size distribution of the technogenic magnetic particles (TMPs) and thus the degree of contamination of the environment. The aim of this contribution is to use magnetic parameters in distinguishing dust from a wide range of sources of air pollution (power industry, cement, coke, ceramic industries and biomass combustion). We measured magnetic susceptibility, hysteresis parameters and thermomagnetic curves. Our results suggest that predominant component in tested samples is magnetite, only dust from coking plant and the combustion of lignite contained also maghemite and/or hematite. Mixture of sizes, ranging from fine single-domain to coarse multi-domain grains, was detected. Our results indicate that industrial dusts from various sources of emissions have different specific magnetic properties and magnetic measurements may provide very helpful information.

  14. Research on flux of dry atmospheric falling dust and its characterization in a subtropical city, Guangzhou, South China.

    Science.gov (United States)

    Zhao, Jinping; Peng, Ping'an; Song, Jianzhong; Ma, Shexia; Sheng, Guoying; Fu, Jiamo

    2010-09-01

    Guangzhou is the central city in the Pearl River Delta (PRD), China, and is one of the most polluted cities in the world. To characterize the ambient falling dust pollution, two typical sampling sites: urban (Wushan) and suburban (University Town) areas in Guangzhou city were chosen for falling dust collection over 1 year at time intervals of 1 or 2 months. The flux of dry deposition was calculated. In addition, mineral composition and morphology of atmospheric falling dust were studied by X-ray diffraction, scanning electron microscopy, and microscopic observation. The results revealed that the dust flux in Guangzhou city was 3.34-3.78 g/(m(2) month) during the study period. The main minerals in the dust were quartz, illite, calcite, kaolinite, gypsum, plagioclase, dolomite, and amorphous matter. The morphological types included grained and flaky individual minerals, chain-like aggregates, spherical flying beads, and irregular aggregates, with the chain-like and spherical aggregates indicators of industrial ash. The major dusts were derived from industrial and construction activities. The gypsum present in the dust collected in winter season was not only derived from cement dust but may also have originated from the reaction of calcic material with sulfuric acids resulting from photooxidation of SO(x) and NO(x), which confirmed serious air pollution due to SO(x) and NO(x) in Guangzhou. The abatement of fossil fuel combustion emissions and construction dust will have a significant beneficial effect on dust reduction.

  15. Crushed Limestone Dust Valorization for Eco Friendly non Fired Wall Tiles

    Directory of Open Access Journals (Sweden)

    Wangrakdiskul Ubolrat

    2016-01-01

    Full Text Available Utilizing crushed limestone dust; the by-product of crushing limestone plant for producing non-fired wall tiles is the objective of this research. The main raw materials of non-fired wall tiles consist of laterite soil, fluvial sand and Portland cement. The crushed limestone dust has been used as the substitute material of non-fired wall tiles for enhancing their bending strength. In this experiment, four groups of formulas have been constructed. Firstly, crushed limestone dust has been mixed into the basic formula for substitution of laterite soil. Secondly, crushed limestone dust has been used for substitution to river soil of the basic formula. Thirdly, it has been substituted to Portland cement in the basic formula. Finally, the best formulas of the first three groups has been selected and mixed up to make the new formulas. After mixing the raw materials of selected formula, forming specimens by uni-axial pressing at 100 bar has been performed. Then, they have been aged for 1 week at the room temperature. After that, testing the specimens’ properties has been carried out. They are bending strength and water absorption which comparing with Thailand Industrial Standard (TIS 614-2529. The experimental results show that adding the crushed limestone dust to the basic composition has an effect on the bending strength and water absorption. The compositions of the best formula are laterite soil 55%, fluvial sand 7.5%, Portland cement 22.5%, and crushed limestone dust 15%. It gives the bending strength by 2.32 MPa, water absorption 3.20%. The water absorption property can pass the TIS standard, but bending strength could not pass. The estimated cost of raw materials is 0.09065 THB/100 g.

  16. Alternative Fuels in Cement Production

    OpenAIRE

    2007-01-01

    Substitutionen af fossilt med alternativt brændsel i cement produktionen er steget betydeligt i den sidste dekade. Af disse nye alternative brændsler, udgør de faste brændsler p.t. den største andel, hvor kød- og benmel, plastic og dæk i særdeleshed har været de alternative brændsler der har bidraget med mest alternativ brændsels energi til den tyske cement industri. De nye alternative brændsler er typisk karakteriseret ved et højt indhold af flygtige bestanddele og adskiller sig typisk fra t...

  17. A Twofold Comparison between Dual Cure Resin Modified Cement and Glass Ionomer Cement for Orthodontic Band Cementation

    Science.gov (United States)

    Attar, Hanaa El; Elhiny, Omnia; Salem, Ghada; Abdelrahman, Ahmed; Attia, Mazen

    2016-01-01

    AIM: To test the solubility of dual cure resin modified resin cement in a food simulating solution and the shear bond strength compared to conventional Glass ionomer cement. MATERIALS AND METHOD: The materials tested were self-adhesive dual cure resin modified cement and Glass Ionomer (GIC). Twenty Teflon moulds were divided into two groups of tens. The first group was injected and packed with the modified resin cement, the second group was packed with GIC. To test the solubility, each mould was weighed before and after being placed in an analytical reagent for 30 days. The solubility was measured as the difference between the initial and final drying mass. To measure the Shear bond strength, 20 freshly extracted wisdom teeth were equally divided into two groups and embedded in self-cure acrylic resin. Four mm sections of stainless steel bands were cemented to the exposed buccal surfaces of teeth under a constant load of 500 g. Shear bond strength was measured using a computer controlled materials testing machine and the load required to deband the samples was recorded in Newtons. RESULTS: GIC showed significantly higher mean weight loss and an insignificant lower Shear bond strength, compared to dual cure resin Cement. CONCLUSION: It was found that dual cure resin modified cement was less soluble than glass ionomer cement and of comparable bond strength rendering it more useful clinically for orthodontic band cementation. PMID:28028417

  18. Influence of the temperature on the cement disintegration in cement-retained implant restorations.

    Science.gov (United States)

    Linkevicius, Tomas; Vindasiute, Egle; Puisys, Algirdas; Linkeviciene, Laura; Svediene, Olga

    2012-01-01

    The aim of this study was to estimate the average disintegration temperature of three dental cements used for the cementation of the implant-supported prostheses. One hundred and twenty metal frameworks were fabricated and cemented on the prosthetic abutments with different dental cements. After heat treatment in the dental furnace, the samples were set for the separation to test the integration of the cement. Results have shown that resin-modified glass-ionomer cement (RGIC) exhibited the lowest disintegration temperature (pcement (ZPC) and dual cure resin cement (RC) (p>0.05). Average separation temperatures: RGIC - 306 ± 23 °C, RC - 363 ± 71 °C, it could not be calculated for the ZPC due to the eight unseparated specimens. Within the limitations of the study, it could be concluded that RGIC cement disintegrates at the lowest temperature and ZPC is not prone to break down after exposure to temperature.

  19. The Paleozoic Dust Bowl: Dust Deposition in Tropical Western Pangaea (Midcontinent U.S.) at the Terminus of the Late Paleozoic Ice Age

    Science.gov (United States)

    Soreghan, G. S.; Heavens, N. G.; Benison, K. C.; Soreghan, M. J.; Mahowald, N. M.; Foster, T.; Zambito, J.; Sweet, A.; Kane, M.

    2012-12-01

    Atmospheric dust is well recognized and studied as both an archive and agent of climate change in Earth's relatively recent past. Archives of past dust include loess deposits and dust recovered from ocean- and ice-cores. Dust remains poorly known in Earth's past prior to the Cenozoic, but is increasingly recognized in the form of paleo-loess deposits, and (epeiric) marine strata that accumulated isolated from fluvio-deltaic influx. Here, we report on the growing recognition of voluminous dust deposits preserved in the Permian record of the U.S. Midcontinent (western tropical Pangaea). Fine-grained redbeds predominate in Permian strata throughout the U.S. Midcontinent, but notably in a swath extending from Oklahoma through South Dakota. These units consist predominantly of red mudstone and siltstone in commonly massive units, but sedimentary structures and bedding that signal aqueous processes (e.g. laminations, ripples) have led most to infer deltaic or tidal deposition. The absence of channel systems to deliver the sediment, as well as the predominantly massive and laterally continuous character and the uniform fine grain size signal wind transport, implying that these units record sustained dust deposition overprinted at times by sub-aqueous deposition in lakes, including ephemeral saline and acid lakes that led to evaporite cementation. Detrital zircon geochronology indicates that much of the dust originated in the relatively distant Appalachian-Ouachita orogenic systems, which formed part of the central Pangaean mountains (CPM), the collisional zone that sutured the supercontinent. Within the Anadarko basin of Oklahoma, Permian redbeds record >2 km of predominantly dust deposition, some of the thickest dust deposits yet documented in Earth's record. Yet the tropical setting is remarkably non-uniformitarian, as much Quaternary loess occurs in mid- to high-latitude regions, commonly linked to glacial genesis. We are currently investigating with both data and

  20. Center for Cement Composite Materials

    Science.gov (United States)

    1990-01-31

    pastes have shown that the matrix is microporous; mesopores are absent unless the material is allowed to dry out. This results in water adsorption at low...only to water. When subsequently dried a portion of3 the porosity is converted to larger mesopores . • Only about one third of the cement reacts in a...Frictional sliding, in this case was characterized by a decreasing slope in the loading curve followed by hysteresis in the unload/reloading curves

  1. Investigation and control measures of occupational hazards in grinding station of a cement enterprise of Aoxi%奥西某水泥公司粉磨站职业病危害调查及控制措施

    Institute of Scientific and Technical Information of China (English)

    卢建国; 朱春兰; 陈枨光

    2013-01-01

    目的 调查奥西某水泥公司水泥粉磨站的工艺特点、职业病危害因素的种类及浓(强)度,提出相应的控制措施.方法 对水泥粉磨站的工艺流程、职业病危害因素种类及现场检测的资料进行收集、整理与分析.结果 该水泥粉磨站工艺特点为采用新技术设备.职业病危害因素主要是粉尘(水泥尘、矽尘、石灰石粉尘、石膏粉尘和熟料尘)和噪声2类.粉尘时间加权平均(TWA)浓度范围0.3~44.4 mg/m3,超标率53.3%;短时间接触浓度(STEL)范围0.3~68.0 mg/m3,超标率19.0%.水泥粉尘浓度超标38.9%~58.3%,熟料尘浓度超标11.1%~33.3%,矽尘、石灰石粉尘和石膏粉尘浓度均在国家职业卫生限值范围内.作业岗位的个体噪声强度为78.9~ 86.4 dB(A),超标率为16.7%.结论 该项目职业病危害因素为水泥粉尘、熟料粉尘和噪声.对此提出了职业病危害预防控制措施和管理措施,以保护劳动者身体健康.%[Objective]To investigate the process characteristics, species and exposure levels of occupational hazards in grinding station of a cement enterprise of Aoxi, and put forward related control measures. [ Methods] The production process, species of occupational hazards and field detection data in the cement grinding station were collected and analyzed. [Results] The cement grinding station technology was characterized by adopting new technology and equipment. Noise and dust (cement dust, silica dust, limestone dust, gypsum dust and clinker dust) were primary occupational hazards. Dust TWA ranged from 0.3-44.4 mg/m3, with over standard rate of 53.3% ; The STEL ranged from 0.3-68.0 mg/m3, with over standard rate of 19.0%. Cement dust concentrations exceeded the standard from 38.9%-58. 3% ; clinker dust concentrations exceeded the standard from 11. 1%-33. 3% ; silica dust, limestone dust and plaster dust concentration were within the national occupation health limits. The individual noise

  2. WHITE CEMENT IN SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Y.C.P RAMANA BABU

    2013-04-01

    Full Text Available India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO and carbon dioxide (CO2 are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat tothe survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green house gases (i.e., CO and CO2 and also saves lot of money in the long run process. A small amount of these gases in environment can cause major problems over time. Use of white cement in composite pavement design where there is heavy traffic loads are acting as well as number of vehicles are more such as junctions, bus stops, check posts etc., can perform better and acts asenvironment friendly. Its light colour reflects more than bituminous pavement so that it can be easily identified and avoid accidents to some extent. White cement helps to lower the average bus stop, junction temperature providing comfort to the people because it has high solar reflectance there by reducing “urban heat island” effect. In addition to this it has some more advantages which increase the sustainability, durability and workability of the pavements.

  3. Sustainable Development of the Cement Industry and Blended Cements to Meet Ecological Challenges

    OpenAIRE

    Konstantin Sobolev

    2003-01-01

    The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA) cement helps to improve its ecologi...

  4. Oblique dust density waves

    Science.gov (United States)

    Piel, Alexander; Arp, Oliver; Menzel, Kristoffer; Klindworth, Markus

    2007-11-01

    We report on experimental observations of dust density waves in a complex (dusty) plasma under microgravity. The plasma is produced in a radio-frequency parallel-plate discharge (argon, p=15Pa, U=65Vpp). Different sizes of dust particles were used (3.4 μm and 6.4μm diameter). The low-frequency (f 11Hz) dust density waves are naturally unstable modes, which are driven by the ion flow in the plasma. Surprisingly, the wave propagation direction is aligned with the ion flow direction in the bulk plasma but becomes oblique at the boundary of the dust cloud with an inclination of 60^o with respect to the plasma boundary. The experimental results are compared with a kinetic model in the electrostatic approximation [1] and a fluid model [2]. Moreover, the role of dust surface waves is discussed. [1] M. Rosenberg, J. Vac. Sci. Technol. A 14, 631 (1996) [2] A. Piel et al, Phys. Rev. Lett. 97, 205009 (2006)

  5. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  6. Pulmonary Cement Embolism following Percutaneous Vertebroplasty

    Directory of Open Access Journals (Sweden)

    Ümran Toru

    2014-01-01

    Full Text Available Percutaneous vertebroplasty is a minimal invasive procedure that is applied for the treatment of osteoporotic vertebral fractures. During vertebroplasty, the leakage of bone cement outside the vertebral body leads to pulmonary cement embolism, which is a serious complication of this procedure. Here we report a 48-year-old man who was admitted to our hospital with dyspnea after percutaneous vertebroplasty and diagnosed as pulmonary cement embolism.

  7. Application of coal-water slurry on the rotary calcining kiln of pedgion magnesium reduction process

    Institute of Scientific and Technical Information of China (English)

    LI Hua-qing; XIE Shui-sheng; LIU Jin-ping; WU Peng-yue; HUANG Guo-jie

    2006-01-01

    Energy saving has been an important concept in modern industry especially to the countries and regions with energy shortage such as China and Japan. Utilization of Coal-Water Slurry (CWS) can improve the burning efficiency of coal and reduce the pollutions of soot, sulfide and the nitride by burning lump coal directly. The CWS is a promising energy saving technique and the effectual substitute of oil. The study on the preparation and application of the CWS has made progresses in many aspects. The present paper studied the basal problems for applying the CWS on the rotary kilns during the calcining-dolomite process in the magnesium factory, summarized the key points for the application process of the CWS and gave the corresponding solutions.

  8. Torrefaction of cedarwood in a pilot scale rotary kiln and the influence of industrial flue gas.

    Science.gov (United States)

    Mei, Yanyang; Liu, Rujie; Yang, Qing; Yang, Haiping; Shao, Jingai; Draper, Christopher; Zhang, Shihong; Chen, Hanping

    2015-02-01

    Torrefaction of cedarwood was performed in a pilot-scale rotary kiln at various temperatures (200, 230, 260 and 290°C). The torrefaction properties, the influence on the grindability and hydroscopicity of the torrefied biomass were investigated in detail as well as the combustion performance. It turned out that, compared with raw biomass, the grindability and the hydrophobicity of the torrefied biomass were significantly improved, and the increasing torrefaction temperature resulted in a decrease in grinding energy consumption and an increase in the proportion of smaller-sized particles. The use of industrial flue gas had a significant influence on the behavior of cedarwood during torrefaction and the properties of the resultant solid products. To optimize the energy density and energy yield, the temperature of torrefaction using flue gas should be controlled within 260°C. Additionally, the combustion of torrefied samples was mainly the combustion of chars, with similar combustion characteristics to lignite.

  9. ENERGY AND MASS TRANSPORT PROCESSES IN THE GRANULAR BED OF AN INDIRECTLY HEATED ROTARY KILN

    Institute of Scientific and Technical Information of China (English)

    Wolfgang Klose; Arndt-Peter Schinkel

    2004-01-01

    The transport mechanisms of momentum, mass, species, and energy are investigated in detail for the rotary kiln process. The residence time prediction of the granular bed is well improved by considering different flow patterns in the drum. Introducing a mixed flow pattem of the basic slipping and slumping behaviour has the most important effect on the improvement of the residence time prediction. The granular bed is assumed to behave as a Bingham fluid in the active layer of the bed. The transport mechanisms of momentum, species, and energy are modelled on the basis of this assumption and using the kinetic gas theory. Additionally, a mathematical transformation is presented to save computational time. The model results of the temperature field are in very good agreement with experimental data.

  10. Flame image recognition of alumina rotary kiln by artificial neural network and support vector machine methods

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-liang; ZOU Zhong; LI Jie; CHEN Xiang-tao

    2008-01-01

    Based on the Fourier transform, a new shape descriptor was proposed to represent the flame image. By employing the shape descriptor as the input, the flame image recognition was studied by the methods of the artificial neural network(ANN) and the support vector machine(SVM) respectively. And the recognition experiments were carried out by using flame image data sampled from an alumina rotary kiln to evaluate their effectiveness. The results show that the two recognition methods can achieve good results, which verify the effectiveness of the shape descriptor. The highest recognition rate is 88.83% for SVM and 87.38% for ANN, which means that the performance of the SVM is better than that of the ANN.

  11. 某节能型套筒石灰窑生产线职业病危害评价分析%Evaluation and Analysis of Occupational Hazards in a Energy-saving Metallurgical Lime Kiln Project

    Institute of Scientific and Technical Information of China (English)

    曹贤文; 杨金星; 王多多; 董吉良

    2011-01-01

    目的 了解某公司新建节能型石灰窑存在的主要职业危害因素,为制定职业病的预防措施提供依据.方法 采用职业卫生学调查、工作场所职业病危害因素现场监测和职业健康检查进行综合评价.结果 该生产线主要存在粉尘、噪声、高温、热辐射、工频电磁场、一氧化碳、二氧化碳、氮氧化物等.粉尘和噪声存在超标,不符合GBZ2.1,2.2-2007的要求.结论 该节能型套筒窑超标岗位在目前生产工艺不能达到有效防护措施前提下应加强个体防护.%Objective To understand the main occupational hazards factors existed in the construction project of metallurgical lime kiln, and provide the basis for the prevention measure of occupational diseases.Methods The comprehensive evaluation was done by using on - site occupational hazard survey, detection of occupational hazards and occupational health check in the workplace.Results The main occupational hazards in the workplace are limestone dust, lime dust,noise, high temperature, heat radiation, frequency electromagnetic fields, carbon monoxide, carbon dioxide, nitrogen oxides.Dust and noise exceeded the standard, and does not meet the standard of Occupational exposure limits for hazardous agents in the workplaceGBZ2.1 and 2.2 - 2007.Conclusion Workers should strengthen individual protection to protect health when the current processing technique cannot reach the effective protective measures at overweight positions.

  12. Planar dust-acoustic waves in electron-positron-ion-dust plasmas with dust size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong-Yan; Zhang, Kai-Biao [Sichuan University of Science and Engineering, Zigong (China)

    2014-06-15

    Nonlinear dust-acoustic solitary waves which are described with a Kortweg-de vries (KdV) equation by using the reductive perturbation method, are investigated in a planar unmagnetized dusty plasma consisting of electrons, positrons, ions and negatively-charged dust particles of different sizes and masses. The effects of the power-law distribution of dust and other plasma parameters on the dust-acoustic solitary waves are studied. Numerical results show that the dust size distribution has a significant influence on the propagation properties of dust-acoustic solitons. The amplitudes of solitary waves in the case of a power-law distribution is observed to be smaller, but the soliton velocity and width are observed to be larger, than those of mono-sized dust grains with an average dust size. Our results indicate that only compressed solitary waves exist in dusty plasma with different dust species. The relevance of the present investigation to interstellar clouds is discussed.

  13. The influence of ultrasound on removal of prefabricated metal post cemented with different resin cements

    Directory of Open Access Journals (Sweden)

    Atiyeh Feiz

    2013-01-01

    Conclusion: Ultrasonic energy did not decrease the retention of posts cemented with Panavia or Maxcem Elite cements. Furthermore, it seems that there is no significant difference between removal force of self-etch (Panavia and the self-etch self-adhesive (Maxcem Elite resin cements.

  14. The mechanical effects of different levels of cement penetration at the cement-bone interface.

    NARCIS (Netherlands)

    Waanders, D.; Janssen, D.; Mann, K.A.; Verdonschot, N.J.J.

    2010-01-01

    The mechanical effects of varying the depth of cement penetration in the cement-bone interface were investigated using finite element analysis (FEA) and validated using companion experimental data. Two FEA models of the cement-bone interface were created from micro-computed tomography data and the p

  15. Mangrove community in an abandoned brick kiln: A structural and association analysis

    Directory of Open Access Journals (Sweden)

    Sumit Manna

    2012-03-01

    Full Text Available Background: The presence of brick kiln along the Hoogly rever sites of lower Bengal is very usual and this phenomenon is not only restricted to India alone but also to the other south Asian countries. The abandoned brick Kiln are important habitat for the formation of mangrove community due to tidal action, loose silty substratum and less anthropogenic interference. In this context, the aim of the present study is to visualize how the structural and association pattern regulate the community dynamics of a mangrove ecosystem. Materials and Methods: The entire study area was divided into 37 units (Quadrats of 27.31 sq m. Structural parameters like density, relative density, abundance, relative abundance, frequency, relative basal area were measured based on vegetation map, prepared through satellite image and ground truthing. Association indices (Ochiai, Dice and Jaccard were measured based on 2X2 contingency/species association table. Results: Out of 10 species under 10 genera and 9 families found in the present habitat, Sonneratia caseolaris is the only mangrove tree species with 155 individuals along with other mangrove associates like Cryptocoryne ciliata, Crinum viviparum, Acanthus ilicifolius and Derris scandens. The high importance value index of Sonneratia caseolaris, Cryptocoryne ciliata, and Crinum viviparum indicated their significant role in community formation. The strong positive association of these 3 species also suggests to help in developing community in stressed environment. Conclusion: Identification of such potential mangrove habitat and study of their community dynamics would be helpful to find out the nature of mangrove establishment for future afforestation programme of threatened mangrove species.

  16. Substantial global carbon uptake by cement carbonation

    Science.gov (United States)

    Xi, Fengming; Davis, Steven J.; Ciais, Philippe; Crawford-Brown, Douglas; Guan, Dabo; Pade, Claus; Shi, Tiemao; Syddall, Mark; Lv, Jie; Ji, Lanzhu; Bing, Longfei; Wang, Jiaoyue; Wei, Wei; Yang, Keun-Hyeok; Lagerblad, Björn; Galan, Isabel; Andrade, Carmen; Zhang, Ying; Liu, Zhu

    2016-12-01

    Calcination of carbonate rocks during the manufacture of cement produced 5% of global CO2 emissions from all industrial process and fossil-fuel combustion in 2013. Considerable attention has been paid to quantifying these industrial process emissions from cement production, but the natural reversal of the process--carbonation--has received little attention in carbon cycle studies. Here, we use new and existing data on cement materials during cement service life, demolition, and secondary use of concrete waste to estimate regional and global CO2 uptake between 1930 and 2013 using an analytical model describing carbonation chemistry. We find that carbonation of cement materials over their life cycle represents a large and growing net sink of CO2, increasing from 0.10 GtC yr-1 in 1998 to 0.25 GtC yr-1 in 2013. In total, we estimate that a cumulative amount of 4.5 GtC has been sequestered in carbonating cement materials from 1930 to 2013, offsetting 43% of the CO2 emissions from production of cement over the same period, not including emissions associated with fossil use during cement production. We conclude that carbonation of cement products represents a substantial carbon sink that is not currently considered in emissions inventories.

  17. Frozen delivery of brushite calcium phosphate cements.

    Science.gov (United States)

    Grover, Liam M; Hofmann, Michael P; Gbureck, Uwe; Kumarasami, Balamurgan; Barralet, Jake E

    2008-11-01

    Calcium phosphate cements typically harden following the combination of a calcium phosphate powder component with an aqueous solution to form a matrix consisting of hydroxyapatite or brushite. The mixing process can be very important to the mechanical properties exhibited by cement materials and consequently when used clinically, since they are usually hand-mixed their mechanical properties are prone to operator-induced variability. It is possible to reduce this variability by pre-mixing the cement, e.g. by replacing the aqueous liquid component with non-reactive glycerol. Here, for the first time, we report the formation of three different pre-mixed brushite cement formulations formed by freezing the cement pastes following combination of the powder and liquid components. When frozen and stored at -80 degrees C or less, significant degradation in compression strength did not occur for the duration of the study (28 days). Interestingly, in the case of the brushite cement formed from the combination of beta-tricalcium phosphate with 2 M orthophosphoric acid solution, freezing the cement paste had the effect of increasing mean compressive strength fivefold (from 4 to 20 MPa). The increase in compression strength was accompanied by a reduction in the setting rate of the cement. As no differences in porosity or degree of reaction were observed, strength improvement was attributed to a modification of crystal morphology and a reduction in damage caused to the cement matrix during manipulation.

  18. Hidration kinetics study of tlie mixed cements

    OpenAIRE

    Duque Fernández, Gabriel . L; Díaz Quintanilla, David; Zapata Sierra, Manuel; Rubio Frías, Ester

    1993-01-01

    A study of the hydration process of cements with 10% and 20% addition of a tuff from "Las Carolinas" quarry (Cienfuegos, Cuba) by different methods was done. The results obtained by different methods showed a good agreement. It was proved an increment of the hydration products, an acceleration of alite hydration and a swelling of the fixed water in mixed cements. The resistance of the cement with 10% addition is similar to that of the pure cement for ages of 28 days, whereas with 20% addition...

  19. Design, quality, and quality assurance of solid recovered fuels for the substitution of fossil feedstock in the cement industry.

    Science.gov (United States)

    Sarc, R; Lorber, K E; Pomberger, R; Rogetzer, M; Sipple, E M

    2014-07-01

    This paper describes the requirements for the production, quality, and quality assurance of solid recovered fuels (SRF) that are increasingly used in the cement industry. Different aspects have to be considered before using SRF as an alternative fuel. Here, a study on the quality of SRF used in the cement industry is presented. This overview is completed by an investigation of type and properties of input materials used at waste splitting and SRF production plants in Austria. As a simplified classification, SRF can be divided into two classes: a fine, high-calorific SRF for the main burner, or coarser SRF material with low calorific value for secondary firing systems, such as precombustion chambers or similar systems. In the present study, SRFs coming from various sources that fall under these two different waste fuel classes are discussed. Both SRFs are actually fired in the grey clinker kiln of the Holcim (Slovensko) plant in Rohožnik (Slovakia). The fine premium-quality material is used in the main burner and the coarse regular-quality material is fed to a FLS Hotdisc combustion device. In general, the alternative fuels are used instead of their substituted fossil fuels. For this, chemical compositions and other properties of SRF were compared to hard coal as one of the most common conventional fuels in Europe. This approach allows to compare the heavy metal input from traditional and alternative fuels and to comment on the legal requirements on SRF that, at the moment, are under development in Europe.

  20. The incorporation of wood waste ash as a partial cement replacement material for making structural grade concrete: An overview

    OpenAIRE

    2015-01-01

    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 alterna...

  1. Dust exposure in Finnish foundries.

    Science.gov (United States)

    Siltanen, E; Koponen, M; Kokko, A; Engström, B; Reponen, J

    1976-01-01

    Dust measurements were made in 51 iron, 9 steel, and 8 nonferrous foundries, at which 4,316 foundrymen were working. The sampling lasted at least two entire shifts or work days continuously during various operations in each foundry. The dust samples were collected at fixed sites or in the breathing zones of the workers. The mass concentration was determined by weighing and the respirable dust fraction was separated by liquid sedimentation. The free silica content was determined by X-ray diffraction. In the study a total of 3,188 samples were collected in the foundries and 6,505 determinations were made in the laboratory. The results indicated a definite difference in the dust exposure during various operations. The highest dust exposures were found during furnace, cupola, and pouring ladle repair. During cleaning work, sand mixing, and shake-out operations excessive silica dust concentrations were also measured. The lowest dust concentrations were measured during melting and pouring operations. Moderate dust concentrations were measured during coremaking and molding operations. The results obtained during the same operations of iron and steel foundries were similar. The distribution of the workers into various exposure categories, the content of respirable dust and quartz, the correlation between respirable dust and total dust, and the correlation between respirable silica and total dust concentrations are discussed. Observations concerning dust suppression and control methods are briefly considered.

  2. Analytical Study of Nonlinear Dust Acoustic Waves in Two-Dimensional Dust Plasma with Dust Charge Variation

    Institute of Scientific and Technical Information of China (English)

    LIN Chang; ZHANG Xiu-Lian

    2005-01-01

    The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation.

  3. Emissions of PCDD/Fs, PBDD/Fs, dioxin like-PCBs and PAHs from a cement plant using a long-term monitoring system.

    Science.gov (United States)

    Conesa, Juan A; Ortuño, Nuria; Abad, Esteban; Rivera-Austrui, Joan

    2016-11-15

    The aim of the present work was to assess the emission of different persistent organic pollutants from a cement plant over a period of one year, under normal operational conditions. Thus, a long-term sampling device was installed in the clinker kiln stack of the cement plant. The factory uses petroleum coke as primary fuel, but also alternative fuels such as solid recovered fuel (SRF), automotive shredder residue (ASR), sewage sludge, waste tires, and meat and bone meal (MBM) wastes, with an energy substitution level of about 40%. Both PCDD/Fs (together with dl-PCBs) and PBDD/Fs were continuously sampled, with a total of ten samples collected in 2-4week periods. Also, PAHs were sampled during one-week periods, in order to evaluate their emissions in three different samples. The emission levels throughout the year were much lower than the set legal limits in all substances, being cement sector, which were 8.5ng I-TEQ/ton clinker for PCDD/Fs and 3.2ng WHO-TEQ/ton clinker for PCBs. With respect to the congener distribution, 2,3,7,8-TCDF accounts for 60 to 68% of the total toxicity for PCDD/Fs, and in PBDD/F emissions, a clear predominance of octa-substituted species (both dioxin and furan) was found.

  4. Biomonitoring of industrial dusts on animals. II. Bioindication on alveolar macrophages.

    Science.gov (United States)

    Kaváciková, Z

    1986-01-01

    Rats and rabbits were exposed through the respiratory system to industrial dusts (magnesite emissions, solid wastes from nickel refinery dump, cement emissions) at biomonitory stations or in experimental chamber. Following exposure the animals were killed, the alveolar macrophages isolated and acid phosphatase and beta-glucuronidase estimated in the isolated cells. The activity of both enzymes was enhanced in the exposed animals in all cases. The enhancement was dependent on the length of exposure and amount of inhaled particles.

  5. Dust Devil Tracks

    Science.gov (United States)

    Reiss, Dennis; Fenton, Lori; Neakrase, Lynn; Zimmerman, Michael; Statella, Thiago; Whelley, Patrick; Rossi, Angelo Pio; Balme, Matthew

    2016-11-01

    Dust devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earth's surface. Dust devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between ˜1 m and ˜1 km, depending on the diameter of dust devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of dust devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial dust layers are removed to expose larger-grained substrate material (coarse sands of ≥500 μm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence leading to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also lead to albedo contrasts when dust is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550-850 nm on Mars and around 0.5 % in the wavelength range from 300-1100 nm on Earth. The removal of an equivalent layer thickness around 1 μm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand

  6. Dust during the Reionization

    CERN Document Server

    Elfgren, E; Elfgren, Erik

    2003-01-01

    The possibility that population III stars have reionized the Universe at redshifts greater than 6 has recently gained momentum with WMAP polarization results. Here we analyse the role of early dust produced by these stars and ejected into the intergalactic medium. We show that this dust, heated by the radiation from the same population III stars, produces a submillimetre excess. The electromagnetic spectrum of this excess is compatible with the FIRAS (Far Infrared Absolute Spectrophotometer) cosmic far infrared background. This spectrum, a Doppler spectrum times the $\

  7. Dust Devil Days

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 6 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. Dust devils, small cyclonic wind storms, are common in the American Southwest and on Mars. As the dust devil moves across the surface it picks up the loose dust, leaving behind a dark track to mark its passage. These dust devil tracks are in the Argyre Basin. Image information: VIS instrument. Latitude -46.6, Longitude 317.5 East (42.5 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the

  8. Removal of chromium from tannery effluents by adsorption.

    Science.gov (United States)

    Fadali, O A; Magdy, Y H; Daifullah, A A M; Ebrahiem, E E; Nassar, M M

    2004-01-01

    Tannery effluent is characterized not only by heavy loads but also with toxic heavy metals especially chromium ions. Chromium is considered an important source of contamination due to large volume of exhaust liquid discharged and solid sludge produced. Details on adsorption studies were carried out using synthetic chromium salts (chromium chloride) as adsorbate, and cement kiln dust (a waste from white cement industry) as adsorbent. Equilibrium isotherms have been determined for the adsorption of chromium ions on cement kiln dust. Kinetic study provided that the adsorption process is diffusion controlled. The experimental results have been fitted using Freundlich, Langmuir, and Redlich Peterson isotherms. The maximum adsorption capacity of cement kiln dust was found to be 33 mg/g. Industrial tannery effluent (22-mg/L chromium and COD 952 mg/L) was also treated by cement dust. The treated effluent (using 20 g cement dust per 1 L) contains only 0.6 mg/L chromium and COD 200 mg/L.

  9. A study on provisional cements, cementation techniques, and their effects on bonding of porcelain laminate veneers.

    Science.gov (United States)

    Vinod Kumar, G; Soorya Poduval, T; Bipin Reddy; Shesha Reddy, P

    2014-03-01

    Minimal tooth preparation is required for porcelain laminate veneers, but interim restorations are a must to protect their teeth against thermal insult, chemical irritation, and to provide aesthetics. Cement remaining after the removal of the provisional restoration can impair the etching quality of the tooth surface and fit and final bonding of the porcelain laminate veneer. This in vitro study examined the tooth surface for remaining debris of cement after removal of a provisional restoration. Determine the presence of cement debris on prepared tooth surface subsequent to the removal of provisional restoration. Determine the cement with the least residue following the cleansing procedures. Determine the effect of smear layer on the amount of residual luting cement. Eighty-four extracted natural anterior teeth were prepared for porcelain laminate veneers. For half of the teeth, the smear layer was removed before luting provisional restorations. Veneer provisional restorations were fabricated and luted to teeth with six bonding methods: varnish combined with glass ionomer cement (GIC), varnish combined with resin modified GIC, varnish, spot etching combined with dual-cure luting cement, adhesive combined with GIC, adhesive combined with resin modified GIC, and adhesive, spot etching combined with dual-cure luting cement. After removal of provisional restorations 1 week later, the tooth surface was examined for residual luting material with SEM. Traces of cement debris were found on all the prepared teeth surfaces for all six groups which were cemented with different methods. Cement debris was seen on teeth subsequent to the removal of provisional's. Dual-cure cement had the least residue following the cleansing procedures. Presence of smear layer had no statistical significance in comparison with cement residue. With the use of adhesive the cement debris was always found to be more than with the use of varnish. GIC showed maximum residual cement followed by dual-cure.

  10. A Model for Formation of Dust, Soil and Rock Coatings on Mars: Physical and Chemical Processes on the Martian Surface

    Science.gov (United States)

    Bishop, Janice; Murchie, Scott L.; Pieters, Carle M.; Zent, Aaron P.

    2001-01-01

    This model is one of many possible scenarios to explain the generation of the current surface material on Mars using chemical, magnetic and spectroscopic data From Mars and geologic analogs from terrestrial sites. One basic premise of this model is that the dust/soil units are not derived exclusively from local rocks, but are rather a product of global, and possibly remote, weathering processes. Another assumption in this model is that there are physical and chemical interactions of the atmospheric dust particles and that these two processes create distinctly different results on the surface. Physical processes distribute dust particles on rocks and drift units, forming physically-aggregated layers; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces and cohesive, crusted surface units between rocks, both of which are relatively permanent materials. According to this model the dominant components of the dust/soil particles are derived from alteration of volcanic ash and tephra, and contain primarily nanophase and poorly crystalline ferric oxides/oxyhydroxide phases as well as silicates. These phases are the alteration products that formed in a low moisture environment. These dust/soil particles also contain a smaller amount of material that was exposed to more water and contains crystalline ferric oxides/oxyhydroxides, sulfates and clay silicates. These components could have formed through hydrothermal alteration at steam vents or fumeroles, thermal fluids, or through evaporite deposits. Wet/dry cycling experiments are presented here on mixtures containing poorly crystalline and crystalline ferric oxides/oxyhydroxides, sulfates and silicates that range in size from nanophase to 1-2 pm diameter particles. Cemented products of these soil mixtures are formed in these experiments and variation in the surface texture was observed for samples containing smectites, non-hydrated silicates or sulfates

  11. Electrostatic Characterization of Lunar Dust

    Science.gov (United States)

    2008-01-01

    To ensure the safety and success of future lunar exploration missions, it is important to measure the toxicity of the lunar dust and its electrostatic properties. The electrostatic properties of lunar dust govern its behavior, from how the dust is deposited in an astronaut s lungs to how it contaminates equipment surfaces. NASA has identified the threat caused by lunar dust as one of the top two problems that need to be solved before returning to the Moon. To understand the electrostatic nature of lunar dust, NASA must answer the following questions: (1) how much charge can accumulate on the dust? (2) how long will the charge remain? and (3) can the dust be removed? These questions can be answered by measuring the electrostatic properties of the dust: its volume resistivity, charge decay, charge-to-mass ratio or chargeability, and dielectric properties.

  12. Microbial analysis of biofilms on cement surfaces: An investigation in cement-associated peri-implantitis.

    Science.gov (United States)

    Korsch, Michael; Walther, Winfried; Marten, Silke-Mareike; Obst, Ursula

    2014-09-05

    The cementation of implant-supported restorations always poses the risk of excess cement retained in the peri-implant sulcus despite careful clinical control. Excess cement can become the basis of colonization by oral microorganisms. As a result of the biofilm formation peri-mucositis or peri-implantitis may develop. Complications were observed in the routine prosthetic restoration of implants when a methacrylate-based cement was used. These developed a few weeks after cementation of the suprastructure and caused bleeding on probing as well as suppuration from the peri-implant tissue. In the revision therapy, excess cement in the peri-implant sulcus was found in many cases. This excess cement was sampled from ten patients and investigated for biofilm formation. For this purpose, the cement samples were collected and analyzed for bacterial in situ colonization by 16S rDNA-based methods. In laboratory experiments, the methacrylate-based cement and two other dental cements were then investigated for their proneness to form biofilm. The results of the in situ and in vitro investigations revealed a strong tendency towards bacterial invasion of the methacrylate-based cement by opportunistic species and pathogens.

  13. Identification of the exploatation dust in road dust

    Directory of Open Access Journals (Sweden)

    B. Gajdzik

    2012-01-01

    Full Text Available The aim of this publication is to determine models of explore dust from vehicle brake systems and the presentationof measurement results of the exploitation dust, which is separate from road dust. The following methods and measuring devices were used: T-01M device, screen analysis, analysis of chemical composition with the use of a scanning microscope with Energy Dispersive x-ray Spectroscopy (EDS analyser. The measurements for identifying this type of dust were conducted on marked sections of roads: motorway, city road and mountain road. The explored dust was distinguished in the following car systems: brakes, clutch plates, tyres and catalytic converters.

  14. Copper Slag Blended Cement: An Environmental Sustainable Approach for Cement Industry in India

    Directory of Open Access Journals (Sweden)

    Jagmeet Singh

    2016-04-01

    Full Text Available Indian cement industry is facing environmental issue of emission of carbon dioxide (CO2, a greenhouse gas. Blended cements including supplementary cementitious materials are substitute of Portland cement to reduce CO2 emission. The present paper investigates theappropriateness of copper slag (CS as supplementary cementitious material. Strength properties and hydration of mixes were determined at different replacement levels of CS with cement. Compressive, flexural and tensile strength of each mix was found out at different curing periods. The hydration of cement was investigated through X-ray diffraction (XRD. The strength test results showed that substitution of up to 20% of CS can significantly replace Portland cement.XRD test results were corresponding to strength test results. The present study encourages the utilization of CS as supplementary cementitious material to make economical and environmentally sustainable blended cement

  15. The influence of cement type and temperature on chloride binding in cement paste

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Korzen, Migge Sofie Hoffmann; Skibsted, Jørgen

    1998-01-01

    This paper describes effects of cement type and temperature on chloride binding in cement paste, which is an important subject in relation to life-time modelling of reinforced concrete structures. The influence of cement type on chloride binding is investigated by substituting cement with pure...... cement clinker. Both theoretical considerations and experimental data for chloride binding in cement pastes are presented. A physico-chemically based model to describe the influence of temperature on physical binding of chloride is presented. Solid-state 27Al and 29Si magic-angle spinning (MAS) nuclear...... magnetic resonance (NMR) spectroscopy has been used for quantification of the anhydrous and hydrated aluminate and silicate phases in the chloride exposed cement pastes. The 27Al isotropic chemical shift and nuclear quadrupole coupling is reported for a synthetic sample of Friedel's salt, Ca2Al(OH)6Cl×2H2O....

  16. Comparison of Domestic and International Calculation Methods of CO2 Emission from Cement Production and the Enlightenments for China%水泥生产碳排放测算的国内外方法比较及借鉴

    Institute of Scientific and Technical Information of China (English)

    魏丹青; 赵建安; 金迁致

    2012-01-01

    The comparison of domestic and international calculation methods of CO2 emission from cement production has important reference value for establishing national calculation standards of CO2 emission from cement production.At present,international organizations like Intergovernmental Panel on Climate Change(IPCC)and World Business Council for Sustainable Development(WDCSD)have promulgated a series of universally applicable methods,and a number of developed countries have also proposed their own calculation systems.In this paper,we first briefly introduced the domestic and international calculation methods of CO2 emission from cement production,and performed a comparison of these methods from four aspects,including operational boundaries,raw material calcination emissions,fuel combustion emissions and indirect emissions.Then we made a discussion about the accuracy and applicability of those methods.The conclusions are as follows:1)Those systems are approximately same in the framework of calculation process,but there are differences in operational boundaries,calculating methods and CO2 emission factors;2)WBCSD-Cement Sustainability Initiative provides the methods of setting operational boundaries for countries or enterprises to choose the scope of accounting and reporting;3)On plant level,calcination CO2 can be calculated in two ways:based on the quantity and composition of the raw mix consumed or based on the clinker produced plus discarded dust.The two approaches are,in theory,equivalent.On country level,the latter approach is usually adopted;4)CO2 from fossil kiln fuels(coal,fuel oil and natural gas)is calculated based on fuel consumption,net calorific values,and CO2 emission factors.For China,low calorific value is applicable;5)On country level,the emissions of external production of electricity consumption should be included in the gross emissions,while indirect emission savings such as heat and power exports should be subtracted from the

  17. Left in the Dust

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    NASA's Stardust spacecraft ended its seven-year voyage January 15 after a safe landing on earth, bringing back a capsule of comet particles and samples of interstellar dust that exceeded the loftiest of expectations of mission scientists. The ensuing studies of the cosmic treasure are expected to shed light on the origins of the solar system and earth itself.

  18. Cylindrically symmetric dust spacetime

    CERN Document Server

    Senovilla, J M M; Senovilla, Jose M. M.; Vera, Raul

    2000-01-01

    We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has new surprising features. The universe is ``closed'' in the sense that the dust expands from a big-bang singularity but recollapses to a big-crunch singularity. In fact, both singularities are connected so that the whole spacetime is ``enclosed'' within a single singularity of general character. The big-bang is not simultaneous for the dust, and in fact the age of the universe as measured by the dust particles depends on the spatial position, an effect due to the inhomogeneity, and their total lifetime has no non-zero lower limit. Part of the big-crunch singularity is naked. The metric depends on a parameter and contains flat spacetime as a non-singular particular case. For appropriate values of the parameter the spacetime is a small perturbation of Minkowski spacetime. This seems to indicate that flat spacetime may be unstable agai...

  19. Cylindrically symmetric dust spacetime

    Science.gov (United States)

    Senovilla, José M. M.

    2000-07-01

    We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has surprising new features. The universe is `closed' in the sense that the dust expands from a big-bang singularity but recollapses to a big-crunch singularity. In fact, both singularities are connected so that the whole spacetime is `enclosed' within a single singularity of general character. The big-bang is not simultaneous for the dust, and in fact the age of the universe as measured by the dust particles depends on the spatial position, an effect due to the inhomogeneity, and their total lifetime has no non-zero lower limit. Part of the big-crunch singularity is naked. The metric depends on a parameter and contains flat spacetime as a non-singular particular case. For appropriate values of the parameter the spacetime is a small perturbation of Minkowski spacetime. This seems to indicate that flat spacetime may be unstable against some global non-vacuum perturbations.

  20. Dust devil dynamics

    Science.gov (United States)

    Horton, W.; Miura, H.; Onishchenko, O.; Couedel, L.; Arnas, C.; Escarguel, A.; Benkadda, S.; Fedun, V.

    2016-06-01

    A self-consistent hydrodynamic model for the solar heating-driven onset of a dust devil vortex is derived and analyzed. The toroidal flows and vertical velocity fields are driven by an instability that arises from the inversion of the mass density stratification produced by solar heating of the sandy surface soil. The nonlinear dynamics in the primary temperature gradient-driven vertical airflows drives a secondary toroidal vortex flow through a parametric interaction in the nonlinear structures. While an external tangential shear flow may initiate energy transfer to the toroidal vortex flow, the nonlinear interactions dominate the transfer of vertical-radial flows into a fast toroidal flow. This secondary flow has a vertical vorticity, while the primary thermal gradient-driven flow produces the toroidal vorticity. Simulations for the complex nonlinear structure are carried out with the passive convection of sand as test particles. Triboelectric charging modeling of the dust is used to estimate the charging of the sand particles. Parameters for a Dust Devil laboratory experiment are proposed considering various working gases and dust particle parameters. The nonlinear dynamics of the toroidal flow driven by the temperature gradient is of generic interest for both neutral gases and plasmas.