中低品位磷矿碳热还原工艺优化

Optimization in Carbothermal Reduction Process of Medium-Low Grade Phosphate Ore

以中低品位磷矿为原料,在1 250℃下,以反应时间、碳过剩系数及硅钙物质的量比为实验因子,磷矿还原率为实验指标,利用响应面法对磷矿碳热还原的工艺参数进行优化。结果表明,反应时间与碳过剩系数之间存在明显的交互作用。1 250℃下的优化工艺条件为:反应时间144 min、碳过剩系数2.28、硅钙物质的量比2.7,在此条件下,磷矿还原率可达95.22%,与模型预测值96.91%接近。采用组成不同的中低品位磷矿矿2进行验证实验,磷矿还原率为95.50%,接近预测值。响应面法优化得到的中低品位磷矿碳热还原工艺有助于热法磷酸工艺降低能耗。

Using medium-low grade phosphate ore as raw material,reaction time,carbon excess coefficient,and molar ratio of silicon and calcium as factors,and reduction rate of phosphate ore as an index,we optimized the carbothermal reduction process of phosphate ore by response surface methodology under 1 250℃.The results show that there is a significant interaction between the reaction time and carbon excess coefficient.Moreover,the optimal process conditions under 1 250℃can be determined as follows:the reaction time of 144 min,the carbon excess coefficient of 2.28,and the molar ratio of silicon and calcium of 2.7.Under above conditions,the reduction rate of phosphate ore reaches 95.22%,which is closer to the predicted value of 96.91%.In addition,the optimal process is verified by medium-low grade phosphate ore 2,and the reduction rate is 95.50%,which is closer to the predicted value.The carbothermal reduction process of phosphate ore optimized by response surface methodology is helpful to reduce energy cost of thermal process phosphonic acid.