Study On The Valuable Metallic Elements Separation And Extraction Of Cr-bearing Vanadium Tailings

There are abundant vanadium-titanium magnetite resources in our country.But Large amounts of vanadium tailings were discharged after the sodium salt roasting-leaching process with vanadium slag,which both a waste of resources and environmentally hazardous.In this thesis,experiments of carbon thermal reduction reaction with Cr-bearing vanadium tailings,leaching and separating experiments with magnetic tailings tailings were conducted on the basis of former research,according to vanadium tailings composition and phase characteristics.Based on the research,a process was proposed combined pyrometallurgy and hydrometallurgy to acquire comprehensive treatment of Cr-bearing vanadium tailings.The research results could achieve innocent treatment of vanadium tailings and use provides reference for resource recycling.The paper’s main research results are as follows.(1)The main phase of vanadium tailings are hematite,spinel and augite phase.V is mainly dissolved in titanium spinel.Cr mainly exists in chromohercynite,a small amount in chromium manganese spinel.At 1200 ℃,spinel phase begins to be destroyed,and ferrochromium is formed after iron and chrome reduction.Titanium carbide and vanadium carbide are formed after vanadium and titanium reduction,which mainly in the phase interface between iron chromium alloy and augite phase at 1200℃.In the condition:reduction temperature 900℃,magnetic field intensity 100mT,after reduction roasting,wet grinding and magnetic separation process,magnetic iron power is acquire.The content of magnetic iron is 88.1%.Vanadium and chromium concentrate in magnetic tailings.(2)Magnetic tailings were leached with mass fraction 80%sulfuric acid,the leaching of V,Cr were effective.As 20%D2EHPA+80%sulfonated kerosene for extraction agent.Extraction experiments were conducted at different pH value in leaching liquid.Iron,titanium,and vanadium could be separated from leaching liquid.After striping raffinate,the titanium solution can be used for titanium dioxide.After striping raffinate,the vanadium solution can be used for ammonium vanadium.At pH=7,hydrolysis raffinate,after the calcination of the hydrolysis product,rough chromium trioxide product was acquired with the mass fraction of 89.6%.(3)Using the method "carbon thermal reduction roasting-magnetic separation-sulfuric acid leaching-D2EHPA stepwise solvent extraction-hydrolysis" dispose of Cr-bearing vanadium tailings,iron,chromium,vanadium and titanium could be comprehensive used.The iron recovery rate of magnetic iron is 57.7%.The chromium recovery of rough chromium trioxide product is 78.7%.The vanadium and chromium content is low in the leaching tailings and exists in the density of spinel phase.The damage of leaching tailings to the environment could be reduced greatly.