摘要:
研究了一种处理钢铁酸洗废液的新方法。在酸洗废液中加入适量钢铁废料，还原FeCl3及去除酸，然后将CaCl2加入到废液中，使Fe2+以FeCl2晶体析出。经过滤后得到FeCl2·4H2O晶体和滤液，FeCl2·4H2O晶体经干燥处理后密封保存。结果表明：酸的去除率大于92%，FeCl3的被还原率大于99%，FeCl2的回收率为71.2%，产品FeCl2·4H2O晶体中FeCl2含量为59%，主要杂质FeCl3和CaCl2含量分别为0.04%，0.33%，基本达到工业级水平。滤液中加入适量CaO以中和少量酸后，可回收CaCl2溶液或稀释后直接排放。整个过程不用加热，不产生酸气污染。此法虽然与焙烧法相比资源利用率略显不足，但与传统的中和法相比却得到了大大的优化。此法投资低，技术较简单，比较适合中小企业。
A new method for a treatment of steel picking liquid waste was researched. For reduction
of FeCl3 and removal of acid, a proper amount of iron and steel scrap were
added to the acid picking wastewater, then CaCl2 was added to the wastewater to make
Fe2+ precipitation by FeCl2·4H2O crystals. The FeCl2·4H2O crystals
and filtrate could be got with filter and the crystals were sealed after drying
treatment. Results of the experiments showed that: the removal rate of acid was
more than 92%, the reduction rate of FeCl3 was more than 99%, the recovery rate
of FeCl2 was 71.2%, the content of FeCl2 in FeCl2·4H2O crystals was 59%, the main impurities of FeCl3 and CaCl2 were 0.04% and 0.33%, respectively. The purity of the product FeCl2·4H2O
arrived at industrial grade. A proper amount of CaO was added to the filtrate
to neutralize the little acid, and finally CaCl2 solution could be recycled or
discharged directly. The whole process without heating and had no acid gas
pollution. Although the resource utilization rate of this method was slightly
insufficient compared with the method of roasting, it had been greatly optimized
compared with the traditional neutralization method. This method was of low
investment, and technology was relatively simple, suitable for small and medium
enterprises.