高砷溶液中和脱砷过程  

Removal of Arsenic from High Arsenic Solutions by Scorodite Precipitation

作　　者：方兆珩[1] 石伟[1] 韩宝玲[1] 夏光祥[1] 

机构地区：[1]中国科学院化工冶金研究所,北京100080

出　　处：《化工冶金》2000年第4期359-362,共4页

基　　金：国家自然科学基金资助项目!(编号:59674023)

摘　　要：从热力学计算及实验两方面研究了酸性冶金废液中以砷酸铁形式中和沉淀脱砷过程。ＮａＯＨ中和沉砷时，溶液含砷量主要取决于终ｐＨ值，在ｐＨ＝５～６的范围内，溶液中砷含量最低。结果表明，采用ＮａＯＨ作中和剂时，为了达到低于０．５ｍｇ／Ｌ的排放标准，需要加入一定量氧化剂（如Ｈ２Ｏ２），使溶液中的砷完全转变成砷酸形式，并需严格控制ｐＨ＝６左右；采用ＣａＣＯ３和ＣａＯ作中和剂，ｐＨ≥６。A dearsenifying process from high concentration arsenate solution by formation of insoluble ferric arsenate is analyzed by thermodynamics and examined experimentally. Ambient temperature precipitation and hydrothermal precipitation as ferric arsenate are investigated. In the precipitating process with NaOH neutralization, the As concentration in solution decreases with pH increased up to pH=6, and then it turns to increase at higher pH. The As concentration in the process effluent is lowered below 0.5 mg/L, the regulatory limit, when the solution is neutralized to pH=6(8 with CaCO3 and CaO in two stages. In the thermal precipitation process, 80% of As in solution is removed and more than 95% of nonferrous metals remains in the solution.

关 键 词：脱砷 砷酸铁 沉淀 金矿 硫化矿 高砷溶液 热力学 

分 类 号：TF831.026[冶金工程—有色金属冶金] TF831.032