响应曲面法优化MgO沉淀离子型稀土矿浸出液工艺

Optimization of Leaching Solution of Magnesium Oxide Precipitated Ionic Rare Earth Ore by Response Surface Methodology

为了对离子型稀土矿的浸出液进行探究,使用MgO作为稀土沉淀剂,在单因素试验的基础上采用响应曲面分析法及Box-Behnken的设计原理,在三因素三水平上建立了MgO沉淀离子型稀土矿浸出液的二次多项数学模型,并以反应生成的沉淀物中RE(OH)3含量和RE沉淀率作响应值,探究了镁与稀土的摩尔比、 MgO料浆加料速度和其中的MgO的质量占比对MgO沉淀离子型稀土矿浸出液的影响。结果表明, MgO沉淀离子型稀土矿浸出液的优化反应条件为:镁与稀土的摩尔比为3,加料速度为2 r·min^-1, MgO质量占比为0.5%。该条件下,模型预测的沉淀物中RE(OH)3含量为86.84%, RE沉淀率为97.43%,实验实际值为沉淀物中RE(OH)3含量为85.9%, RE沉淀率为97.51%,两者误差较小,方案可信。

In this experiment, ionic rare earth ore leachate was studied, and the magnesium oxide was used as rare earth precipitant. On the basis of the single factor test, the response surface analysis method and the principle of Box-Behnken were adopted to establish a quadratic mathematical model for the preparation of magnesia precipitation ion-type rare earth ore leachate on the three factors and three levels. The content of RE(OH)3 in the precipitate and RE precipitation rate were used as response values, and the effects of molar ratio of magnesium to rare earth, feed rate of magnesium oxide slurry, and mass fraction of magnesium oxide in magnesium oxide slurry on the precipitation of magnesia precipitation ion-type rare earth ore leachate were investigated. The results showed that the optimum conditions for the preparation of magnesia precipitation ion-type rare earth ore leachate solution were: molar ratio of magnesium to rare earth was 3, the feed rate was 2 r·min^-1, and the mass ratio of magnesium oxide was 0.5%. Under this condition, the RE(OH)3 content in the sediments predicted by the model is 86.84%, the RE precipitation rate is 97.43%, and the experimental actual value of RE(OH)3 content in the sediments is 85.9%, the RE precipitation rate is 97.51%. The error between the two is small and the scheme is credible.