Study On Thermodynamics And Process Of Carbothermal Reduction Of Alkali-boiled Black And White Tungsten Slag

China is not only full of abundant tungsten resources but also has great capacity in tungsten production.The current tungsten production technology is mainly alkali boiling and leaching process.About 80000 tons of tungsten slag is produced in the alkali boiling process every year,and the existing tungsten slag has reached millions of tons.Because of the harmful elements such as lead and arsenic in the slag,it has been listed in the national list of hazardous wastes.In addition,the slag also contains tungsten,tin,niobium,iron,manganese and other valuable elements.In this paper,the valuable elements and harmful elements in the alkali tungsten slag are treated innocuously and resource.The black and white tungsten slag is studied by carbon heat reduction treatment,and the harmful elements such as arsenic and lead are brought into the dust while tungsten,tin,niobium and other valuable elements are accumulated in the alloy.The contents and main results of the paper are as follows:The phase composition of the black and white tungsten slag was clarified by MLA,XRD and SEM EDS.The main elements iron and manganese in the alkali boiled black and white tungsten slag are mainly amorphous colloids,tungsten is mainly wrapped by ferromanganese colloid in the form of wolframite,scheelite and new calcium tungstate.Tin and niobium are mainly embedded in ferromanganese colloid in the form of cassiterite and niobium oxide,while bismuth,lead and arsenic are dispersed in ferromanganese silica colloid.The valuable elements were simplified to oxides,then HSC thermodynamic software was used to proceed the thermodynamic calculation of the carbon thermal reduction process of the black and white tungsten slag.The order of carbon thermal reduction of each element is:Sn O₂>WO₃>Fe₂O₃>Nb₂O₅>Mn O>Ta₂O₅.The effects of temperature and reducing agent on the preparation of alloy by carbon thermal reduction of black and white tungsten slag were studied.The best conditions for carbon thermal reduction were 10%of reducing agent,1500?melting temperature,and the alloying rate of Fe,Mn,W,Nb and Sn into the alloy reached99.1%,26.9%,96.04%,81.57%and 60.69%respectively.The effective enrichment and recovery of valuable metals were obtained,It laid the foundation for the follow-up utilization.The transformation law of the carbon thermal reduction process of the black and white tungsten slag by SEM analysis at different temperatures is expounded.That is,with the increase of temperature,the high price iron and manganese oxides are reduced gradually,and Mn O is reduced into the alloy at 1300?.