响应面法优化含锰钛白废水制备碳酸锰的工艺

Process optimization of preparation of manganese carbonate from manganese-containing titanium dioxide wastewater by response surface methodology

以硫酸法钛白粉生产过程产生的含锰废水为原料,以碳酸氢铵溶液为沉淀剂,十二烷基硫酸钠为添加剂,采用液相沉淀法对废水中的锰进行资源化回收。在单因素实验基础上,采用响应面法中的Box-Behnken Design优化实验设计,分别考察了反应温度、过量系数、pH和陈化时间四因素对碳酸锰沉淀率的影响,建立了响应值与影响因素间的回归方程,并确定了优化条件为:反应温度33.3℃、过量系数1.06、pH=7.2、陈化时间2.0h,在该条件下锰的沉淀率预测值为99.30%,相应的实验值为98.90%,预测值与实验值相对误差仅0.4%,表明响应面法所建立的预测锰沉淀率的模型可靠;所得产品经电感耦合等离子体发射光谱仪(ICP-AES)分析锰含量为43.53%,符合工业碳酸锰(HG/T 4203-2011)质量标准中对碳酸锰纯度的要求。研究结果为含锰废水的资源化回收提供了新思路。

The method of liquid phase precipitation with ammonium bicarbonate solution as precipitant and sodium dodecyl sulfate as an additive was used to recover manganese from wastewaters produced from sulfate titanium dioxide preparation wastewater. Based on results of single factor tests, Box-Behnken Design, a kind of response surface methodology, was used to investigate the effects of reaction temperature, excess coefficient of ammonium bicarbonate(NH4 HCO3), pH of the solution and aging time on the precipitation of manganese precipitation rate. Based on the regression analysis, regression equations related to response values and factors were established. The optimal process conditions were determined as follows: reaction temperature of 33.3℃, excess coefficient of 1.06, solution pH of 7.2, and aging time of 2.0 h. The predicted precipitation rate of manganese was 99.30%, while the corresponding experimental result was 98.90%. The errors between the predicted and experimental value was 0.4%,which indicated that established models were accurate and reliable for the analysis and prediction of the process of the manganese precipitation rate. In the optimized conditions, the manganese content in the manganese carbonate was 43.53% by ICP-AES analysis method, which reached the standard of industrial grade product(HG/T 4203-2011). This study could provide a new idea for the resource reclamation of manganese-containing wastewater.