含镉烟灰在酸性介质中的浸出行为及过程优化

对含镉烟灰的物相组成进行了系统分析,并提出针对性的工艺流程。针对硫酸浸出含镉烟灰的过程,采用响应曲面设计方法对操作条件进行了优化,考察了反应温度、液固比、硫酸浓度及其交互作用对Cd、As、Zn浸出率的影响关系,构建了二阶数学模型和三维响应曲面图,确定了Cd、Zn、As的浸出率分别大于92%、95%和50%的优化浸出条件区域,即反应温度25~60℃,液固比6~8 mL/g,硫酸浓度0.3~0.4 mol/L。结果表明:该模型能够准确预测含镉烟灰在硫酸中的浸出效果;在最优区域内,As的浸出率较低,其主要原因是原料中的砷酸锌在低酸条件未分解。

Leaching behavior of Cd contained dust in acid medium and process optimization

A systematic analysis for Cd contained dust was conducted and a flow sheet for metal recovery was proposed.The central composite design was used to optimize the operating conditions of leaching process.Second-order polynomial models of high significance and 3D response surface plots were constructed to show the interaction effects of temperature,L/S ratio and H2SO4 concentration on the leaching efficiency of Cd,As and Zn.Optimum area of leaching efficiency of Cd,Zn and As bigger than 92%,95% and 50%,respectively,is obtained by the overlaid contours at temperature of 20?60℃,L/S ratio of 6?8 mL/g and H2SO4 concentration of 0.3?0.4 mol/L.The models are proved to be reliable and accurate in predicting the leaching process by the verified experiment in the optimal area.Within the optimal area,the leaching efficiency of As is lower and the main reason is attributed to the insolubility of zinc arsenate.