In order to relieve the equipment corrosion,reduce chlorine and increase phosphorus contents in leaching solution,theleaching behavior of potassium from phosphorus-potassium associated ore in the mixed acids of hydrochloric acid and phosphoricacid was investigated.The effects of various factors,such as mass fraction of hydrochloric acid,solid-to-liquid ratio,material ratio(CaF2dosage(g)/mass of ore(g))and leaching temperature were comprehensively studied.It was found that the dissolution fractionof potassium can reach more than86%under the optimum conditions of leaching temperature95°C,HCl concentration10%,leaching time6h,solid/liquid ratio1:5,and material ratio0.1.In addition,the leaching kinetics of potassium was successfullymodeled by a semi-empirical kinetic model based on the classic shrinking core model.The data showed that the leaching process ofpotassium was controlled by the product layer diffusion and the apparent activation energy for the process was found to be54.67kJ/mol over the temperature range from65to95°C.
Jia-yu MAXue-lan DUYuan-hang QINZai-kun WURu-an CHICun-wen WANG
研究了盐酸和萤石低温酸浸磷钾伴生矿提钾的工艺过程。探讨了各工艺参数对钾浸出率的影响,并采用响应面法对酸浸工艺进行了优化,得出最佳工艺条件为:m(萤石)/m(矿粉)为0.2,盐酸质量分数为22.5%,盐酸用量为79.7 m L,加热温度为92.2℃,反应时间为4.2 h。在此条件下模型预测的钾元素理论浸出率为92.8%,实验验证浸出率为91.3%。
