离子型稀土尾矿的氨氮淋洗去除

Removal of ammonia nitrogen from ion type tailings

针对离子型稀土尾矿中的氨氮残留污染问题,研究淋洗除铵对尾矿的影响,比较氯化钙、氯化镁和钙镁混合液分别在0.01、0.015和0.02 mol/L下的除铵效率,然后利用塔板理论分析除铵效率,优选除铵方案。结果表明:在不同浓度条件下,3种淋洗剂淋洗尾矿的除铵效率分别为62.49%~73.95%、58.64%~65.9%和53.22%~58.92%,除铵效率与淋洗剂中阳离子交换能力和浓度均呈正相关。基于塔板理论计算,3种淋洗剂下的理论塔板高度分别为10.00~11.10 mm、18.15~20.81 mm和12.72~18.77 mm,单块塔板的除铵效率分别为1.35%~1.23%、1.05%~0.88%、和1.10%~0.95%。理论塔板高度越小,单块塔板的平均除铵效率越高,尾矿整体氨氮去除效果就越好。考虑对矿山环境保护的要求,选用0.015 mol/L的氯化钙作为淋洗剂。

Aiming at the problem of ammonia nitrogen residual pollution in ion type rare earth tailings, the effects of flushing ammonium removal experiments on tailings were studied, and the ammonium removal efficiencies of calcium chloride, magnesium chloride and calcium magnesium mixture were compared at 0.01, 0.015 and 0.02 mol/L, respectively, then using the plate theory, the ammonium removal efficiencies were analyzed, and the ammonium removal scheme were optimized. The conclusions are as follows: firstly, the removal efficiency of three kinds of eluents are 62.49%-73.95%, 58.64%-65.9% and 53.22%-58.92% under three concentration conditions,respectively. The removal efficiency is positively related to cation exchange capacity and eluent concentration.Secondly, based on the plate theory, the theoretical plate heights under three kinds of eluents are 10-11.1 mm,18.15-20.81 mm and 12.72-18.77 mm, respectively, and the efficiencies of ammonium removal of single plate are 1.35%-1.23%, 1.05%-0.88% and 1.10%-0.95%, respectively. The smaller the theoretical tray height is, the higher the average efficiency of ammonium removal of single plate is, and the better the overall ammonia nitrogen removal effect of tailings is. Considering the requirements for mine environmental protection, 0.015 mol/L calcium chloride eluent was selected as the suitable eluent.