磷矿在磷酸中的浸出行为

为改进湿法磷酸生产工艺,提高副产石膏的品质,缓解湿法磷酸中固体副产物磷石膏带来的环保压力,进行了磷-硫两步法酸解磷矿制磷酸的研究。着重对贵阳某磷矿在磷酸中的浸出行为进行研究。结果表明,磷矿粒度小于75 μm、搅拌速度为500 r/min、反应温度为70 ℃、五氧化二磷质量分数为40%、反应时间为60 min时,磷矿分解率达到98.5%。德罗兹多夫动力学经验模型能够较好地描述40%五氧化二磷中磷矿反应速率的变化规律,且阻缓系数较大,表观活化能为6.048 kJ/mol,表明40%五氧化二磷中磷酸分解磷矿的反应速率受扩散控制。酸解渣SEM和EDS分析表明反应产物磷酸二氢钙结晶析出是影响扩散的主要因素。

Leaching behavior of phosphate ore in phosphoric acid

In order to improve the production process of wet-process phosphoric acid,improve the quality of by-product phosphogypsum,and relieve the environmental pressure caused by the solid by-products in the wet-process phosphoric acid,the research on phosphorus-sulfur two-step decomposition of phosphate ore to produce phosphoric acid was conducted.The leaching behavior of a phosphate ore in GuiYang in phosphoric acid was especially studied.The results showed that when the particle size of phosphate ore was less than 75 μm,the stirring speed was 500 r/min,the reaction temperature was 70 ℃,the w（P₂O₅） was 40% and the reaction time was 60 min,the decomposition rate of phosphate ore reached 98.5%.The decomposition rate of phosphate ore in 40% P₂O₅ could be described by the Drozdov kinetic empirical model well.The reaction retardation coefficient was large,and the apparent activation energy of the reaction was 6.048 kJ/mol.It was shown that the decomposition of phosphate ore by 40% P₂O₅ was controlled by diffusion.SEM and EDS analysis of the residues showed that the crystallization of calcium dihydrogen phosphate was the main factor affecting the diffusion.