Study On The Resource Utilization Of Alkaline Slag From Tungsten Smelting

With the continuous advancement of China’s industrialization process and the increasing importance of resources,the resource utilization of industrial solid waste has gradually become a hot issue.Tungsten smelting slag is the smelting solid waste produced in the process of APT’s production of tungsten hydrometallurgy process.Its main body is the alkaline slag produced by high alkali pressure leaching process,which has the obvious characteristics of large storage,high environmental hazard and increasing output year by year.How to deal with it effectively is a common problem to be solved urgently in the tungsten smelting industry.In view of its composition characteristics,tungsten smelting alkaline slag is not only a hazardous solid waste,but also a secondary resource with important recycling value.In this paper,the mixed alkaline tungsten slag is taken as the research object,and the systematic research is carried out for its resource utilization.Firstly,in the research of valuable metals’recovery,through the comprehensive analysis of the original slag samples,it was found that the main metals with recycling value were tungsten and tin.On the basis of exploring the feasibility of the test,the experimental study of comprehensive recovery of tungsten and tin by gravity separation was carried out.Micro-fine gravity separation equipment Knelson centrifugal concentrator is used for first concentration.Under the optimized conditions of grinding fineness of 65%,pulp density of 20%,relative gravity multiple of 80g and backwash water flow of 2.75L/min,the acquired yield of crude concentrate is 18.25%,WO₃ and Sn grades are 3.14%and 2.78%respectively,and the recovery are 47.36%and 74.61%respectively.The results show that the effect of tailings discarding of concentrator is well,but the loss of tungsten is large,while the recovery rate of tin is high.Computational fluid dynamics simulation software ANSYS Fluent was used to simulate and analyze the separation process of a centrifugal concentrator,and the analysis results were consistent with the experimental phenomenon to a certain extent In order to improve the recovery effect furtherly,the experimental research of the cleaning process were conducted.Under the combined gravity concentration cut flow,the acquired concentrate yield is 9.12%,Sn grade is 4.13%,and the recovery is 55.43%.Concurrently,the WO3 grade of concentrate is about 4.7%,and the recovery is 36%.The effective recovery of metallic tin in tungsten slag and the partial recovery of tungsten are achieved.Based on comprehensive analysis,a feasible way for efficient comprehensive recovery of tungsten and tin from tungsten slag is proposed.Furtherly,an experimental study on the preparation of tungsten slag based high-strength sintered ceramsite was conducted.Under optimized conditions,high-strength ceramic particles with good comprehensive performance were prepared using recleaning tungsten slag as the main raw material,achieving efficient and harmless comprehensive utilization of tungsten slag without generating waste residue.Analysis show that the sintering condition is the key factor for the preparation of tungsten slag ceramsite.The organic matter contained in the tungsten slag and the composition of low melting point make the internal pores of ceramsite develop well.The phase analysis of ceramsite shows that its main phases are anorthite and plagioclase.Fe,Mn,Zn and other metals contained in it participate in the formation of spinel,and tungsten trioxide mainly exists in the framework structure of ceramsite in the form of melting uncertainty,All phases jointly promote the high strength of ceramsite.Under the optimized conditions:the ratio of tungsten slag to clay is 11:9,preheat temperature of 400℃,preheat time of 20 min,sintering temperature of 1150℃,and sintering time of 30 min,the comprehensive properties of ceramsite products are as follows:apparent density is 1713 kg/m³,bulk density is 892 kg/m³,single particle compressive strength is 15.64 MPa,cylinder compressive strength is 18.37 MPa,1h water absorption is 8.79%.The product conforms to the requirements of 900 density grade in GB/T 17431.2-2010"Lightweight aggregates and its test methods Part 1",and its heavy metal leaching toxicity conforms to the requirements of GB5085.3-2002"Identification standard for hazardous wastes".