硝酸分解磷钾矿的浸出工艺及动力学

Leaching process and kinetics of phosphorus⁃potassium ore decomposition by nitric acid

针对硫酸法湿法磷酸工艺分解磷钾矿难以实现工业规模化连续生产的问题,提出了硝酸法加工磷钾矿的新技术。研究了反应温度、液固质量比、硝酸质量分数、颗粒细度等因素对硝酸浸出磷钾矿中磷浸出率的影响,结果表明:磷浸出率随着反应温度、液固质量比、硝酸质量分数的增加而增加,而随着磷钾矿粒度和磷酸浓度的增加而减小;在温度为50℃、液固质量比为7.3∶1、硝酸质量分数为40%、反应时间为1 h条件下,磷、钾浸出率分别为96.62%、2.45%,实现了磷的高效浸出和磷钾元素的分离。动力学分析表明,磷元素的浸出属于固体产物层扩散控制,活化能为4.77 kJ/mol,研究结果可为磷钾矿的利用提供新思路。

In order to solve the problem that it is difficult to achieve industrial scale continuous production of phosphorous⁃potassium ore by wet phosphoric acid process,a new technology of processing phosphorus⁃potassium ore by nitric acid method was investigated.The effects of reaction temperature,liquid⁃solid mass ratio,nitric acid concentration and particle fineness on phosphorus leaching rate of phosphorus⁃potassium associated ore by nitric acid leaching were studied.The re⁃sults showed that the leaching rate of phosphorus was increased with the increase of reaction temperature,liquid⁃solid mass ratio,nitric acid concentration,and decreased with the increase of phosphoric acid concentration and particle size.Under the optimized conditions of temperature of 50℃,liquid⁃solid mass ratio of 7.3∶1,nitric acid concentration of 40%and reac⁃tion time of 1 h,the leaching rates of phosphorus and potassium were 96.62%and 2.45%,respectively,realizing efficient leaching of phosphorus and separation of phosphorus and potassium elements.The kinetic analysis showed that the leaching of phosphorus was belonged to solid product layer diffusion control,and the activation energy was 4.77 kJ/mol.The research results could provide a new idea for the utilization of phosphorus⁃potassium ore.