Method for recycling metal in tungsten carbide waste through fluoride electrolysis

Abstract

The invention provides a method for recycling metal in tungsten carbide waste through fluoride electrolysis. The method is characterized in that the tungsten carbide waste is taken as an anode; high-temperature fluoride is taken as electrolyte; the high-temperature fluoride is one or more of NaF, KF, MgF2, RbF and CaF2; and the tungsten carbide waste is WC alloy waste or WC alloy waste containing Co with mass fraction being 2-20%. According to the method provided by the invention, a fluoride molten salt system has the characteristics of a relatively high electrochemical window at a high temperature, relatively great ionic conductivity, a relatively low molten salt loss rate and relatively strong corrosion; the fluoride molten salt system is taken as a molten salt dielectric medium, so that electrochemical activities, at a high temperature, of WC waste and a waste hard alloy are improved, and therefore, electrochemical dissolution speed of WC waste and the waste hard alloy is quickened.

Description

technical field [0001] The invention belongs to the technical field of molten salt electrolysis, and in particular relates to an electrolysis method for waste cemented carbide. Background technique [0002] Cemented carbide is generally a material with high hardness and high bending strength made of refractory metal tungsten carbide and bonding metal through powder metallurgy. It is used in machinery manufacturing, mining, transportation, energy exploration, It has been widely used in architectural decoration and other fields [1] . However, refractory metal tungsten and rare metal cobalt are recognized as extremely important strategic elements in the world, and have a very important impact on improving national economy and military competitiveness. At present, more than 50% of the world's tungsten resources are used to manufacture cemented carbide, and the tungsten content in waste cemented carbide has reached 74%-91%. China consumes about 27,000 tons of tungsten metal eve...

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Problems solved by technology

However, this method has the following disadvantages (1) the chloride medium used has a large volatilization loss at high temperature, which cannot ensure the stability and continuity of the electrolysis process; (2) the electrochemical window of the chloride medium is narrow, and cannot be improved during the electrolysis process. The larger voltage value and current value make the electrochemical dissolution rate of waste cemented carbide slower; (3) in the longer electrolysis process, the cathode material used in this method will be mixed with the molten salt medium or the cathode obtained by electrolysis. The product reacts, causing the cathode product to be impure; (4) This method proposes to use tungstate and tungsten chloride in the molten salt medium to accelerate the dissolution of tungsten carbide waste and waste cemented carbide, because tungstate ions are oxygen-containing complexes Ions, during the electrochemical reduction process, oxygen ions will be precipitated at the anode to generate oxygen. With the extension of the electrolysis process, the oxygen concentration in the electrolytic cell increases, and there are higher requirements for the purity of the cathode product and the life of the electrolytic cell at high temperature. , while the oxidation of oxygen ions consumes part of the current, reducing the current efficiency of the entire electrolysis process

At the same time, the cost of tungsten chloride is high, and it exists in gaseous form in a high temperature environment, so that tungsten chloride cannot be used as a liquid active substance to accelerate the dissolution of tungsten carbide waste and waste cemented carbide.

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