低品位磷矿制取磷酸试验研究

Experimental Research of Preparation of Phosphoric Acid from Low-Grade Phosphate Rock

随着世界磷矿资源日渐枯竭,低品位磷矿的开发利用显得非常迫切.本研究采用硝酸分解低品位磷矿,以磷矿中P2O5的浸取率为指标,考察了硝酸的质量分数、酸比、反应温度、反应时间的影响,从而确定了硝酸分解低品位磷矿的最佳工艺条件为:硝酸质量分数29%、酸比8、反应温度60℃、反应时间45 min;在此最佳条件下,对磷矿P2O5的浸取率为98.1%;而且通过扫描电镜观察了不同反应时间下磷矿颗粒表面的形貌特征的变化.实验结果为两步法分解低品位磷矿制取磷酸并联产硫酸钙晶须的研究和可行性论证提供了基础数据.

As the phosphate rock resources exhausts gradually in the world,exploiting and utilizing low-grade phosphate rock is becoming very pressing.This study adopts nitric acid to decompose low-grade phosphate rock.Aiming at the improvement of the extraction rate of P2O5 from phosphate rock,the mass fraction of nitric acid,acid ratio,reaction temperature and reaction time are researched.The optimum technological conditions of using nitric acid to dissolve low-grade phosphate rock are thus obtained： the mass fraction of nitric acid is 29%,acid ratio 8,the temperature of reaction 60℃ and reaction time 45 min.With these optimum conditions,the extraction rate of P2O5 from phosphate rock reaches 98.1%.Scanning election microscope is then employed to observe the changes of morphology characteristics in the surface of phosphate rock at different reaction time.The experimental results provide the basic data and feasibility analysis for preparing phosphoric acid by using two-step method to decompose low-grade phosphate rock and jointly produce calcium sulfate whisker.