Effect Of Carbon On The Process Of Preparing Vanadium Alloys By Electrolysis Method

Metal vanadium has a high melting point,high hardness,good thermal conductivity and chemical stability,which is widely used in steel,non-ferrous metallurgy,aerospace,chemistry and new energy fields.China has abundant vanadium resources,accounting for19.6%of the world's recoverable reserves,but with a low comprehensive utilization level.The traditional preparation processes of vanadium and vanadium alloys have high energy consumption and high cost,limiting vanadium and vanadium alloys to a certain extent of use.The molten salt electrolysis method can realize the short-process preparation from metal oxide to metal,which is expected to reduce the production cost and promote the comprehensive utilization of vanadium resources.However,preparing metals and their alloys by molten salt electrolysis still has a problem of low current efficiency.In this paper,the molten salt electrolysis process is used to prepare vanadium alloys.Focus on the problem of low current efficiency and the negative impact of carbon in the process.studies have been carried out from two aspects:the interface effect of the electrolysis system and the improvement of the macro electrolytic cell structure.Further exploratory research on the use of carbon to prepare ceramic composite materials in the electrolysis process directly has been carried out on this basis.The main conclusions of the paper are listed as follows:(1)Molten salt electrolysis of vanadium and other metal oxide mixtures can directly prepare vanadium alloys.When the carbonaceous materials are used in the molten salt electrolysis method as the anode,it will cause serious molten salt and carbon pollution of the products.The accumulation of carbon on the surface of molten salt causes the short circuit,which reduces the current efficiency of the electrolysis process.(2)V₂O₅ electrolytic deoxidation process mainly has four stages.(?)V₂O₅ direct electron deoxidation to generate V₂O₃,the removal of O^2-is captured by Ca²⁺in molten salt to generate CaO,CaO will react with V₂O₃to form the mesophase CaV₂O₄;(?)CaV₂O₄ and V₂O₃ are further electrolytically deoxidized to produce VO_x;(?)VO_x gets electrons to deep deoxidize to form vanadium oxide solid solution(V-O);(?)V-O slowly deoxidizes.(3)CaCl₂-KCl mixed molten salt system can improve the wettability between molten salt and graphite electrode.The addition of 30 wt%of KCl to CaCl₂ molten salt is beneficial to reduce the carbon pollution of molten salt.The carbon content in the cathode product has been reduced by 68.64%,and the current efficiency has been increased by 38.99%.The CaCl₂-KCl system can suppress the cathodic carbon evolution reaction during the electrolysis process,reduce the influence of carbon on the cathode product and improve the current efficiency of the electrolysis process.(4)Improved cell structure can reduce the influence of carbon on the current efficiency of the process to a certain extent.The U-shaped electrolytic cell structure is more complex,which is not conducive to process and further enlarget.Although the cathode sleeve electrolytic cell can reduce molten salt carbon pollution and improve current efficiency,the structure is more complicated,and the operability is not strong.The electrolytic cell with a separator can avoid the short circuit,and reduce the molten salt carbon pollution,and the processing and amplification are relatively simple and easy to realize.The current efficiency increased 44.38%with a separator in the electrolytic cell(5)When the molten salt electrolysis process uses carbonaceous materials as the anode,the VC ceramic layer composite material can be directly prepared.The ceramic layer of the composite material is integrated with the matrix via the coupling of oxide electrolytic deoxidation and metal carbonization,provides a new idea for a carbide ceramic layer preparation.