微波强化焙烧铬铁矿液相氧化浸出研究

Study on liquid phase oxidation leaching of chromiteby microwave enhanced roasting

为了缩短铬铁矿在高浓度氢氧化钠水溶液中高压氧化浸出时间,通过微波焙烧铬铁矿矿石进行预处理。研究了微波焙烧对铬铁矿结构和浸出行为的影响,结果表明:在800℃下微波焙烧铬铁矿后,铬铁矿表面出现大量裂纹,结构不再致密,大大降低了铬铁矿粒径。在温度为240℃、氧分压为2.2 MPa、碱矿比(质量比)为4∶1、搅拌速度700 r/min、NaOH浓度为60 wt.%的条件下,反应120 min,铬浸出率达97.81%以上,表明采用微波焙烧铬铁矿进行压力氧化浸出可大大提高铬的浸出效率。

In order to shorten the high pressure oxidation leaching time of chromite in a high concentration of sodium hydroxide aqueous solution,this paper pretreats chromite ore by microwave roasting.The effect of microwave roasting on the structure and leaching of chromite is investigated.The results show that,after microwave roasting at 800℃,a large number of cracks appear on the surface of chromite,the structure is no longer dense,and the particle size of the chromite greatly reduces.Under the reaction conditions of a temperature of 240℃,O 2 partial pressure of 2.2 MPa,NaOH-to-ore ratio of 4∶1,stirring speed of 700 r/min and NaOH concentration of 60 wt.%,the chromium leaching rate reaches over 97.81%after a reaction time of 120 min.The results show that using microwave roasted chromite for pressure oxidation leaching can greatly improve chromium leaching efficiency.