以提锂副产镁渣为原料,经预处理提纯、除杂后进行高温煅烧,煅烧后的产物与特定比例的氧化钙、萤石、硅铁球磨混合、压片,在高温真空环境下进行还原炼镁实验。采用正交实验法研究了不同工艺参数对镁还原率的影响,利用XRD、XRF、SEM和EDS对预处理镁渣、煅烧后镁渣、还原镁渣以及还原得到的粗镁的物相、结构、组分和微观形貌等进行研究。结果表明,影响镁还原率的工艺参数依次为:萤石添加量>氧化镁煅烧温度>钙镁摩尔比>氧化钙煅烧温度>制片压强。最优炼镁实验方案为:氧化镁煅烧温度为800℃、氧化钙煅烧温度为900℃、钙镁摩尔比为1.4、压力为6 MPa、萤石添加质量分数为5%,此时镁还原率达83.41%。

Waste magnesium slag generated during the extraction of lithium from salt lake is successively pretreated,purified and calcined at a high temperature.The calcined products are mixed with specific ratios of calcium oxide,fluorite and ferrosilicon for ball milling and pressing,and then used to refine magnesium under the high-temperature and vacuum conditions.The orthogonal experimental method is employed to study the effects of different process parameters on the magnesium reduction rate.The phases,structures,components,and microscopic morphology of pre-treated magnesium slag,calcined magnesium slag,reduced magnesium slag,and crude magnesium obtained from reduction are studied by means of XRD,XRF,SEM,and EDS.The results show that the process parameters affecting the magnesium reduction rate are in order of importance:fluorite addition amount>magnesium oxide calcination temperature>calcium-magnesium ratio>calcium oxide calcination temperature>pressing pressure.The optimal magnesium refining experimental scheme is determined as follows:magnesium oxide is calcined at 800℃,calcium oxide is calcined at 900℃,the molar ratio of calcium-magnesium is 1.4,the pressing pressure is 6 MPa,and the addition amount of fluorite is 5%,under which the reduction rate of magnesium reaches 83.41%.

乔小斌(1995-),男,硕士生,主要从事硅热法炼镁工艺研究,1439602293@qq.com。