细粒磷矿硫酸酸解过程的磷石膏结晶研究

Phosphogypsum crystallization in the decomposition process of fine-grained phosphate rock with sulfuric acid

本文以浮选后的细颗粒（55-60μm）马边磷矿为代表性矿样,通过正交实验设计及极差分析方法探讨反应温度、停留时间、液相SO3质量浓度、料浆液固比等因素对细粒磷矿分解及磷石膏结晶的影响。结果表明：细粒磷矿分解的实验室较佳工艺条件为：反应温度85℃、液相SO3质量浓度0.040 g/mL、液固比3.0∶1、反应时间4.0 h。在此工艺条件下,磷酸的萃取率为93.43%,磷石膏的平均粒径为74.47μm。同时对实验数据进行回归分析,得到细粒磷矿磷酸萃取率和磷石膏平均粒径的数学模型,该模型能较好地预测和优化细粒磷矿分解和磷石膏结晶的过程。

In this paper,the Mabian phosphate concentrate with average particle size of 55-60 μm was selected as the representative sample to study the influence of reaction factors on phosphate rock decomposition and phosphogymsum crystallization by Orthogonal Experiments and range analysis method.The reaction factors include reaction temperature,reaction residence time,SO3 concentration,liquid-solid ratio.The results showed that the optimal conditions were reaction temperature at 85 ℃,SO3 concentration at 0.040 g/mL,liquid/solid at 3.0 and reaction time for 4.0 h.Under the optimal conditions,the extraction rate of phosphoric acid from phosphate rock could be 93.43% and the average particle size of phosphogymsum crystal could be 74.47 μm.Through the regression analysis of experimental results,the mathematical model of the phosphate rock decomposition and average particle size of phosphogymsum could be obtained and the dynamic equations could predict and optimize the decomposition process of the fine-grained phosphate rock and the crystallization process of phosphogypsum.