制备高品质磷石膏的湿法磷酸新工艺的开发

采用三级磷酸逆流萃取,然后加硫酸结晶的方法制备出高品质的磷酸和磷石膏。利用单因素实验法考察了温度、液固比、反应时间以及硫酸的用量对P₂O₅和各杂质萃取率的影响;通过实验确定最佳反应温度90℃,最佳反应时间2h,最佳液固比12:1,第三级硫酸的最佳用量为1.2%;萃取率达到98%以上;产品磷酸中的杂质CaO、Al₂O₃、Fe₂O₃、MgO含量分别下降到0.29%、0.11%、0.24%、0.431%;制备出白色的磷石膏,所得石膏采用水热法制备出晶形好和长径比较大的晶须;此法能运用到其他低品位的矿,适应性强,能够实现经济附加值,有广阔的推广前景。

Development of the new wet phosphoric process of preparing high-quality phosphogypsum

By level 3 phosphoric acid reflux extraction, then add sulfate crystallization method to make high quality phosphoric acid and phosphorus gypsum.Using the method of single factor experiment investigates the temperature, solid-liquid ratio, reaction time and the amount of sulfuric acid influence on extraction rate of P₂O₅ and each impurity. Determined by experiment, the best reaction temperature was 90℃, the best reaction time was 2h, best liquid-solid ratio was 12:1 and in the third level, the best dosage of sulfuric acid was 1.2%; Extraction rate reached 98% or more. The impurity in the phosphoric acid product,content of CaO, Al₂O₃, Fe₂O₃, MgO dropped respectively to 0.29%, 0.11%, 0.24% and 0.431%; Prepare white phosphorus gypsum, by hydrothermal method to make good crystal shape and length to diameter was larger whisker. This method can apply to other low grade ore, has strong adaptability, and can realize the economic value added with broad prospects for promotion.