沉钒上层液用硫酸铝除硅制备低硅氢氧化铬研究

Preparation of low-silicon chromium hydroxide by removing silicon from upper liquid of precipitation vanadium with aluminum sulfate

钒渣提钒过程产生的沉钒上层液中六价铬质量浓度为0.3～6.5 g/L、硅质量浓度为0.3～0.9 g/L。沉钒上层液中含有铬(Ⅵ),若直接排放对人类的健康危害较大。以硫酸铝为脱硅剂,采用沉淀法脱除沉钒上层液中的硅制备低硅氢氧化铬。实验结果表明,在除硅温度为65～75℃、溶液pH为8.5～9.5、硅铝质量比为1∶0.4、除硅时间为20～30 min条件下,除硅率达到95%以上,制备的氢氧化铬中硅质量分数(以二氧化硅计)达到0.26%。制备的低硅氢氧化铬可以作为产品出售,也可以作为冶炼低硅金属铬的原料。

The mass concentrations of hexavalent chromium and silicon in upper solution of vanadium precipitation produced in vanadium extraction from vanadium slag are0.3~6.5g/L and0.3~0.9g/L,respectively.The vanadium precipitation upper solution contains hexavalent chromium,which is harmful to human health if it is directly discharged.Using aluminum sulfate as desilication agent,low silicon chromium hydroxide was prepared by precipitation method from the vanadium precipitation upper solution.The results showed that under the conditions of silicon removal temperature of 65~75℃,pH of 8.5~9.5,m(Si)∶m(Al)=1∶0.4and silicon removal time of 20~30min,the silicon removal rate reached over 95%.The prepared chromium hy droxide had a silicon content(calculated as SiO2mass fraction)of0.26%.Low silicon chromium hydroxide can be sold as a product,or as a smelting raw material of low silicon chromium metal.