煤矸石在新型动态循环淋溶装置中的淋溶特性

发布时间：2018-01-31 18:19

本文关键词： 煤矸石径向流循环淋溶淋溶液特性重金属　出处：《中国环境科学》2016年07期 　论文类型：期刊论文

【摘要】：采用新型循环淋溶装置对煤矸石进行连续240h的淋溶实验,研究了煤矸石中重金属在淋溶过程中的溶出规律,通过向淋溶液中添加聚丙烯酰胺(CPAM)考察了固体颗粒物的沉降特性.结果表明:随着淋溶反应时间延长,煤矸石中碱金属Na元素溶于水,形成碱性溶液,这两种因素导致淋溶反应初期淋溶液p H值升高.As、Zn离子浓度在淋溶时间为1~24h时呈上升趋势,而在24~72h,离子浓度呈下降趋势.淋溶液中Cr、Pb、Ba离子浓度在120h内均呈现上升趋势,而在120~240h,对于Cr离子来说,淋溶液的碱性环境促使Cr离子溶出率增大,但取样次数的增多也对Cr离子的浓度降低起到促进作用;淋溶液稀释和Ba离子的沉淀化合物形成,导致淋溶液中Ba离子浓度降低.120~240h,淋溶液中有机物被微生物的生化作用分解以及取样后外加塌陷区水体对淋溶液中COD和BOD起到稀释作用,使COD和BOD降低.在淋溶反应24h内,淋溶液中TON和NH_3-N出现波浪式变化,淋溶时间大于24h时,TON和NH_3-N总体呈升高趋势.随着淋溶时间延长,淋溶液中的固体颗粒物沉降速度逐渐变慢,延长了沉降时间.煤矸石中一些含氮化合物溶解于水中,使淋溶液中电离出NH_4~+离子,形成碱性环境.
[Abstract]:The leaching experiment of coal gangue was carried out for 240 hours with a new circulating leaching device, and the leaching law of heavy metals in coal gangue during leaching was studied. The sedimentation characteristics of solid particles were investigated by adding polyacrylamide (CPAM) to leaching solution. The results showed that Na in coal gangue dissolved in water with the prolongation of leaching time. The alkaline solution was formed. These two factors led to the increase of pH value of leaching solution at the initial stage of leaching reaction. The concentration of Zn ion increased when the leaching time was 1 ~ 24 h, but increased at 24 h. The concentration of Cr ~ (2 +) Pb ~ (2 +) in leaching solution increased within 120 h, but at 120 ~ 240 h, for Cr ~ (2 +). The alkaline environment of leaching solution promoted the dissolution rate of Cr ion, but the increase of sampling times also promoted the decrease of Cr ion concentration. The dilution of leaching solution and the formation of precipitated compounds of Ba ions resulted in the decrease of concentration of Ba ions in leaching solution for .120 ~ 240 h. The organic matter in leaching solution was decomposed by biochemistry action of microorganism and the water body in the collapsing area diluted the COD and BOD in the leaching solution after sampling. The COD and BOD were decreased and the leaching reaction was carried out within 24 hours. The changes of TON and NH_3-N in leaching solution were wave-like, and when the leaching time was longer than 24 h, ton and NH_3-N showed a general increasing trend, and with the prolongation of leaching time. The settling rate of solid particles in leaching solution became slower and the settling time was prolonged. Some nitrogen-containing compounds in coal gangue dissolved in water, so that NH _ 4 ~ + ions were ionized out from leaching solution and the alkaline environment was formed.
【作者单位】：中国矿业大学(北京)化学与环境工程学院;内蒙古工业大学能源与动力工程学院;
【基金】：国家自然科学基金项目(51074170) 新疆维吾尔族自治区科技攻关计划(201532108) 国土资源部煤炭资源勘查与综合利用重点实验室开放研究课题(KF2015-3)
【分类号】：X752
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