沉钒废水除硅制备冶金级氢氧化铬研究

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

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。

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 silicon 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.