硝酸浸出—沉淀法梯级提取磷精矿中的磷和稀土

Step extraction of rare earth and phosphorus from phosphorus concentrate by nitric acid leaching-precipitation method

采用硝酸浸出—沉淀法梯级提取磷精矿中的磷和稀土。采用硝酸溶液浸出磷精矿,并重点研究硝酸浓度和浸出温度对磷和稀土浸出的影响。针对硝酸浸出液,先后通过加入草酸和氯化钙沉淀剂分步梯级沉淀溶液中的稀土和磷,并重点研究草酸用量对稀土沉淀以及氯化钙用量对沉磷的影响。结果表明:在液固比5、硝酸浓度400 g/L、常温条件下浸出2 h得到硝酸浸出液,硝酸浸出液分步沉淀提取草酸稀土和活性磷酸钙;最终获得P_(2)O_(5)品位为38.54%的活性磷酸钙,P_(2)O_(5)回收率为99.04%,REO品位为1.673%的草酸稀土,REO回收率为95.28%,可实现磷和稀土的有效分离。

Phosphorus and rare earth in phosphorus concentrate were extracted by nitric acid leaching-precipitation step by step.Phosphorus concentrate was leached with nitric acid solution,and the effects of nitric acid concentration and leaching temperature on phosphorus and rare earth leaching were studied.For nitric acid leaching solution,the rare earth and phosphorus in the solution are precipitated step by step by adding oxalic acid and calcium chloride precipitator,and the effect of oxalic acid dosage on rare earth precipitation and calcium chloride dosage on phosphorus precipitation is emphasized.The results showed that the nitric acid leaching solution was obtained under the condition of liquid solid ratio of 5,nitric acid concentration of 400 g/L and room temperature decomposition for 2 hours.Rare earth oxalate and activated calcium phosphate was extracted by nitric acid leaching solution.Finally active calcium phosphate products with P_(2)O_(5) grade of 38.54%and P_(2)O_(5) recovery of 99.04%,and rare earth oxalate with REO grade of 1.673%and REO recovery of 95.28%were obtained.The separation of phosphorus and rare earth was realized at room temperature.