TRANSFORMATION OF Cr CHEMICAL FORMS IN CEMENT KILNS CO-PROCESSING Cr CONTAMINATED SOIL
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摘要: 为了对水泥熟料中的水溶性类Cr(Ⅵ)化合物从源头入窑废物控制以达到合理处置铬污染土壤的目的,以生料中Cr(Ⅲ)转化为熟料中Cr(Ⅵ)及水溶性Cr(Ⅵ)转化率为切入点展开探究。采用实验室模拟实验结合现场实验分别对含Cr污染土壤(CCS)中Cr元素煅烧前后质量平衡,Cr(Ⅲ)转化为Cr(Ⅵ)的转化率以及水溶性Cr(Ⅵ)的转化率进行研究。结果发现:Cr总量在煅烧前后基本未发生改变;在模拟煅烧实验中,Cr(Ⅲ)→Cr(Ⅵ)的转化率仅为40%左右,但在现场实验中可达到90%左右;水溶性Cr(Ⅵ)仅在现场实验工况下的熟料中检测到,Cr(Ⅵ)中水溶性Cr(Ⅵ)占比为60%~69%,水溶性Cr(Ⅵ)的转化率为35.40%。水泥产品中的水溶性Cr(Ⅵ)检测结果中复合型硅酸盐水泥中水溶性Cr(Ⅵ)含量低于GB 31893-2015《水泥中水溶性铬(Ⅵ)的限值及测定方法》中的相应限值10 mg/kg。Abstract: To control water-soluble Cr(Ⅵ) compound in cement clinker from the waste source into the kiln, and make sure the reasonable co-processing of chromium contaminated soil, this paper put forward the conversion rate from Cr(Ⅲ) in raw materials to Cr(Ⅵ) and water soluble Cr(Ⅵ) in the clinker as the breakthrough point and then conduct a research. The experiments were carried out under simulated and field test conditions, and the results were calculated through mass balancing method and conversion rate of Cr(Ⅵ). It was found that the total amount of Cr changed slightly before and after calcination, and the conversion rates of Cr(Ⅲ) to Cr(Ⅵ) in simulated calcination experiment and field test were 40% and 90%, respectively. The water-soluble Cr(Ⅵ) was only detected in clinker in filed test, with a proportion of 60%~69% of total Cr(Ⅵ). Eventually, the conversion rate of water-soluble Cr (Ⅵ) was calculated to be approximately 35.40%. The mixing degree of air and raw material showed an significant impact on the conversion rate of Cr(Ⅲ) to water-soluble Cr(Ⅵ). The analysis of cement product revealed that the concentration of water-soluble Cr(Ⅵ) was slightly higher in composite Portland cement, but still below the allowable limit in China's nation standard GB 31893-2015.
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Key words:
- cement kiln /
- contaminated soil /
- co-processing /
- Cr(Ⅵ) /
- conversion rate
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[1] 江玲龙, 李瑞雯, 毛月强, 等. 铬渣处理技术与综合利用现状研究[J]. 环境科学与技术, 2013,36(增刊1):480-483. [2] 徐小希. 水泥基复合材料对铬污染土壤的固化/稳定化研究[D]. 杭州:浙江大学, 2012. [3] HAN R R, ZHOU B H, HUANG Y Y, et al. Bibliometric overview of research trends on heavy metal health risks and impacts in 1989-2018[J]. Journal of Cleaner Production, 2020,276:123249. [4] LIU G N, TAO L, LIU X H, et al. Heavy metal speciation and pollution of agricultural soils along Jishui River in non-ferrous metal mine area in Jiangxi Province, China[J]. Journal of Geochemical Exploration, 2013,132:156-163. [5] 丁琼, 彭政, 闫大海, 等. 欧盟水泥窑协同处置发展对我国的启示[J]. 环境保护, 2015,43(增刊1):89-91. [6] SHEN D S, HUANG M R, FENG H J, et al. Effect of waste addition points on the chromium teachability of cement produced by co-processing of tannery sludge[J]. Waste Management, 2017,61(Mar.):345-353. [7] 王益峰, 祝红梅, 蒋旭光. 水泥窑协同处置危险废物的研究现状及其发展[J]. 环境污染与防治, 2018,40(8):943-949. [8] CHEN X L, LI X M, XU D D, et al. Application of nanoscale zero-valent iron in hexavalent chromium-contaminated soil:a review[J]. Nanotechnology Reviews (Berlin), 2020,9(1):736-750. [9] 马雯, 呼世斌. 以城市污泥为掺料制备烧结砖[J]. 环境工程学报, 2012,6(3):1035-1038. [10] KARIUS V, HAMER K. PH and grain-size variation in leaching tests with bricks made of harbour sediments compared to commercial bricks[J]. Science of the Total Environment, 2001,278(1/2/3):73-85. [11] HU H Y, LIU H, SHEN W Q, et al. Comparison of CaO's effect on the fate of heavy metals during thermal treatment of two typical types of MSWI fly ashes in China[J]. Chemosphere, 2013,93(4):590-596. [12] 杨玉飞, 杨昱, 黄启飞, 等. 废物水泥窑共处置产品中重金属的释放特性[J]. 中国环境科学, 2009,29(2):175-180. [13] 兰明章, 张迪. 水泥熟料形成过程中重金属价态变化分析[J]. 青岛理工大学学报, 2009,30(4):31-33. [14] 范兴广, 杨玉飞, 黄启飞, 等. 水泥窑共处置含Cr废物中Cr在不同温度下的形态转化[J]. 环境科学研究, 2014,27(3):272-278. [15] MAO L Q, GAO B Y, DENG N, et al. Oxidation behavior of Cr(Ⅲ) during thermal treatment of chromium hydroxide in the presence of alkali and alkaline earth metal chlorides[J]. Chemosphere, 2016,145:1-9. [16] CHENG S K, SHUI Z H, YU R, et al. Durability and environment evaluation of an eco-friendly cement-based material incorporating recycled chromium containing slag[J]. Journal of Cleaner Production, 2018,185:23-31. [17] WU J N, LI C L, YANG F. The disposition of chromite ore processing residue (COPR) incorporating industrial symbiosis[J]. Journal of Cleaner Production, 2015,95:156-162. [18] SHI H S, KAN L L. Study on the properties of chromium residue-cement matrices (CRCM) and the influences of superplasticizers on chromium(Ⅵ)-immobilising capability of cement matrices[J]. Journal of Hazardous Materials, 2009,162(2/3):913-919. [19] 刘宇程, 陈文博, 陈媛媛, 等. 水泥窑协同处置掺加萃余钻屑对水泥熟料性能的影响[J]. 环境工程, 2020,38(11):157-162. [20] 李斌斌, 范海宏, 马增, 等. 水泥熟料对污泥中重金属的固化特性[J]. 硅酸盐通报, 2016,35(6):1891-1896. [21] KROBTHONG J, RACHAKORNKIJ M, SRICHAROENCHAIKUL V. Distributions of Cr, Ni, Cu and Zn in hazardous waste Co-processing in a pilot-scale rotary cement kiln[J]. Journal of Applied ences, 2012,12(1):22-31. [22] 张日旭, 蒋旭光, 池涌, 等. 酸洗污泥与煤共燃烧过程中重金属的迁移分布研究[J]. 燃料化学学报, 2015,43(7):790-797. [23] 李立园, 汤泉, 郑刘根, 等. 不同燃烧温度下煤中铬迁移和释放特性[J]. 环境化学, 2018,37(3):437-444. [24] 李静. 铬污染土壤替代硅质原料烧制水泥熟料研究[D]. 杭州:浙江大学, 2013. [25] HORSLEY C, EMMERT M H, SAKULICH A. Influence of alternative fuels on trace element content of ordinary portland cement[J]. Fuel, 2016,184(15):481-489. [26] PERES V, FAVERGEON L, ANDRIEU M, et al. High temperature chromium volatilization from Cr2O3 powder and Cr2O3-doped UO2 pellets in reducing atmospheres[J]. Journal of Nuclear Materials, 2012,423(1/2/3):93-101. [27] A P K, B E P, A S V, et al. Incineration of tannery sludge under oxic and anoxic conditions:study of chromium speciation[J]. Journal of Hazardous Materials, 2015,283:672-679. [28] CHEN J, JIAO F, ZHANG L, et al. Use of synchrotron XANES and Cr-doped coal to further confirm the vaporization of organically bound cr and the formation of chromium(Ⅵ) during coal oxy-fuel combustion[J]. Environmental Science & Technology, 2012,46(6):3567-3573. [29] LI Y Q, WANG H Z, ZHANG J, et al. The industrial practice of Co-processing sewage sludge in cement kiln[J]. Procedia Environmental Sciences, 2012,16:628-632. [30] FAN H D, LV M Q, WANG X S, et al. Effect of Cr on the mineral structure and composition of cement clinker and its solidification behavior[J]. Materials, 2020,13(7):1529. [31] TANG W W, ZENG G M, GONG J L, et al. Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials:a review[J]. Science of the Total Environment, 2014,468/469:1014-1027. [32] LI B D, JIAN S W, ZHU Q, et al. Effect of flux components of lightweight aggregate on physical properties and heavy metal solidification performance[J]. Waste Management, 2020,118:131-138. [33] ZHAO P D, ZHANG H, YU J, et al. Conditions for mutual conversion of Cr(Ⅲ) and Cr(Ⅵ) in aluminum chromium slag[J]. Journal of Alloys and Compounds, 2019,788:506-513. [34] PARIRENYATWA S, ESCUDERO-CASTEJON L, SANCHEZ-SEGADO S, et al. Comparative study of alkali roasting and leaching of chromite ores and titaniferous minerals[J]. Hydrometallurgy, 2016,165:213-226. [35] VERBINNEN B, BILLEN P, CONINCKXLOO M V, et al. Heating temperature dependence of Cr(Ⅲ) oxidation in the presence of alkali and alkaline earth salts and subsequent Cr(Ⅵ) leaching behavior[J]. Environmental Science & Technology, 2013,47(11):5858-5863.
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