钾长石-磷酸钙-石墨体系提取钾的实验研究

Experimental research on potassium extraction from potassium feldspar-calcium phosphate-graphite system

文中研究了钾长石-磷酸钙-石墨体系焙烧提取钾的工艺,通过助熔剂焙烧-水洗浸出-钾盐结晶分离工艺提高钾的提取率。在热力学分析的基础上,考察了还原剂用量、焙烧温度、钙硅摩尔比、助熔剂加入量对钾挥发率和浸出率的影响。结果表明,当m(富钾板岩)∶m(磷酸钙)∶m(石墨)=3.2∶1∶0.9、助熔剂氯化钙的加入量为钾长石质量的40%、反应温度为1350℃、焙烧时间为2 h时,钾的提取率超过95%,且磷酸钙中大部分的磷被还原,该工艺具有良好的工业应用前景。

The process of roasting on potassium extraction from the potassium feldspar-calcium phosphate-graphite system was scrutinized,and the extraction ratio of potassium was improved by flux roasting,water immersion and potassium salt crystallization separation processes.Based on thermodynamic analysis,the effects of reducing agent dosage,roasting temperature,calcium-silicon molar ratio and flux addition on the volatilization rate and leaching ratio of potassium were investigated.The results show that when the mass ratio of reactants is m(potassium-rich slate):m(calcium phosphate):m(graphite)=3.2∶1∶0.9,CaCl_(2)is added as an auxiliary and roasted at 1350℃for 2 h,the extraction ratio of potassium can reach more than 95%,and most of the phosphorus in calcium phosphate is reduced.The process enjoys a good industrial application prospect.