Abstract The recovery of chromium from vanadium precipitated solution obtained by adding Ca(OH)2 into the chromium-containing vanadate solution and ball milling was investigated by precipitation with lead salt and leaching with sodium carbonate. It has been found that chromium can be effectively enriched by adding PbCO3. The precipitate is the mixture of PbCO3 and PbCrO4∙PbO. The concentration of Cr residue in the solution can be decreased to 16.0 mg/L by adding PbCO3 into vanadium precipitated solution according to Pb/Cr molar ratio 4.0 and adjusting the pH to 12.5 with NaOH stirring for 180 min at 20 °C. Then the precipitates were leached with hot Na2CO3 solution under pH 10.0 at 50 °C to obtain the leach solution containing Na2CrO4 and the leach residue containing PbCO3. After filtration, the leach residue was reused in Cr precipitation and the leach solution was used to circularly leach the Cr precipitate until Na2CrO4 near saturation. Finally, the product of Na2CrO4∙4H2O with purity 99.3% was obtained by evaporation and crystallization of the leach solution.

中文翻译：

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铅盐沉淀碳酸钠浸出钒沉淀液中铬的回收

摘要 以铅盐沉淀、碳酸钠浸出的方法，研究了在含铬钒酸盐溶液中加入Ca(OH)2，球磨制得的钒沉淀溶液中铬的回收。已经发现添加PbCO3可以有效地富集铬。沉淀物是 PbCO3 和 PbCrO4∙PbO 的混合物。将PbCO3按Pb/Cr摩尔比4.0加入钒沉淀溶液中，在20℃下用NaOH搅拌180分钟将pH值调至12.5，可使溶液中Cr残留物浓度降至16.0mg/L。然后将沉淀物用热的 Na2CO3 溶液在 pH 10.0 和 50°C 下浸出，得到含有 Na2CrO4 的浸出液和含有 PbCO3 的浸出残渣。过滤后，浸出残渣回用于Cr沉淀，用浸出液循环浸出Cr沉淀直至Na2CrO4接近饱和。最后通过浸出液蒸发结晶得到纯度为99.3%的Na2CrO4∙4H2O产物。