利用铬铁合金生产铬盐的新工艺研究

针对目前铬盐生产中存在的六价铬污染问题,介绍了“铬铁-三价铬冶金化工联合法”新型无污染的铬盐生产工艺。新工艺以铬铁合金为原料,用硫酸作为浸出剂,将合金中的铬和铁浸出,浸出后的硫酸铬溶液经过硫化除杂、草酸沉铁和萃取深度除杂、沉淀氢氧化铬及煅烧,制备出氧化铬。整个工艺过程中的铬都是以三价形态存在,彻底解决了传统铬盐生产工艺中存在的六价铬污染问题。对于铬铁合金中伴生的大量铁,通过除杂可以生产电池材料磷酸铁锂的原料——草酸亚铁,实现了资源的综合回收利用,并可以产生很好的经济效益。该工艺铬的浸出率可以达到99%,生产的氧化铬纯度可以达到99%以上,而且粒度分布很好,可以用于颜料行业及冶金行业,生产流程简单,易于实现产业化。

Study on new process of producing chromium salt with ferrochrome alloy

In view of the pollution problem of hexavalent chromium existing in the production of chromium salt at present,the new ferrochrome-trivalent chromic ion metallurgical-chemical combination method without hexavalent chromium pollution was introduced.In the new process,ferrochrome alloy was used as raw material and sulfuric acid was employed as leaching agent,the purified chromium sulphate solution was obtained after removing impurities with sulfide,precipitating iron with ox-alate and extraction,chromium oxide could be prepared with the purified chromium sulphate solution after precipitation of chromium hydroxide and calcination of chromium hydroxide.The chromium element existed with the form of Cr(Ⅲ) in the whole new process and the pollution problem caused by hexavalent chromium ion was completely resolved.The comprehensive uti-lization of resources could be realized in the new process.The iron associated with chromium in the ferrochrome alloy after leaching with sulfuric acid and removing impurities could be precipitated as ferrous oxalate with oxalate,ferrous oxalate was used as the raw material of preparation of lithium iron phosphate,the comprehensive utilization of resources and good econo-mic benefits could be achieved.The leaching rate of chromium could reach 99%,the purity of chromium oxide could be over 99% with good particle size distribution,chromium oxide could be used in the paint industry and metallurgy industry.The new process is simple and easy to realize industrialization.