煤矸石在新型动态循环淋溶装置中的淋溶特性

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pH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NH₃-N出现波浪式变化，淋溶时间大于24h时，TON和NH₃-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 NH₄⁺离子，形成碱性环境.

Leaching characteristics of coal gangue in a new dynamic cyclic leaching device

The leaching rule of heavy metals in coal gangue was studied by 240 h sequential cyclic leaching experiments which were carried out in a new dynamic cyclic radial flow leaching device. CPAM was added to the leaching solution to investigate the sedimentation characteristics of the solid particles. Results showed that, Na in coal gangue was dissolved in the water and formed alkaline solution when the time of leaching reaction extended, leading to a higher pH at the beginning of the reaction. The concentration of As and Zn ions was increasing during the first 24h of leaching but decreased from the 24^th to 72^nd hours. The concentration of Cr, Pb and Ba was all increasing during the first 120h. The leaching rate of Cr irons increased by the alkalinity of the leaching solution from the 120^th hour to the 240^th, but the concentration decreased as the times of sample test increased. Pb ions were oxidized into smaller solubility of precipitation in the process of leaching, which decreased the migration ability of Pb ions to the leaching solution. The concentration of Ba irons in the leaching solution decreased as the solution diluted and sediments of Ba irons formed. During the period from the 120^th hour to the 240^th, the organics in the solution were decomposed by microorganism, and water was added. Therefore, the concentration of COD and BOD was diluted. In the first 24h, the values of TON and NH₃-N had a wave type change, both of which increased after 24h. The sedimentation rate of the solid particles in the leaching solution slowed down as the leaching time extended, and prolonged the sedimentation duration. Some nitrogen compounds in coal gangue were dissolved in water, and ionization of ammonium ions in the leaching solution formed the alkaline environment.