沉钒废水除硅制备冶金级氢氧化铬研究

研究了以石灰为脱硅剂,采用石灰+片碱（氢氧化钠）沉淀法脱除沉钒废水中的硅,以除硅液为原料制备冶金级氢氧化铬。结果表明,先用石灰调节pH为7.5~8.0,再用片碱调节pH为9.5以上,除硅温度为55~65 ℃,除硅时间为20~30 min,在此条件下除硅率达到67.9%。沉钒废水用石灰除硅后制备的氢氧化铬硅含量低,以二氧化硅质量分数计达到4.2%,可用于冶炼焊剂用、铝剂用金属铬的原料。

Study on preparation of metallurgical grade chromium hydroxide by removing silicon from vanadium wastewater

Using lime powder as the desiliconizing agent,and the metallurgical grade chromium hydroxide was prepared from vanadium precipitation wastewater by lime powder+sodium hydroxide precipitation method.The results showed that the sili-con removal rate reached 67.9% under the conditions of first adjusting the pH at 7.5~8.0 with lime powder,then adjusting the pH above 9.5 with sodium hydroxide,the silicon removal temperature of 55~65 ℃ and the silicon removal time of 20~30 min. The prepared chromium hydroxide had a silicon content（calculated as SiO₂ mass fraction） of 4.2% and a low silicon content by removing silicon with lime powder.Low-silicon chromium hydroxide can be used as chromium metal smelting raw materials for welding flux and aluminum.