Study On Leaching Behavior Of V And Fe In The Vanadium Extraction Process From Stone Coal Vanadium Ore

China is a large country with vanadium resources and its reserves rank first in the world.The stone coal vanadium ore is a characteristic vanadium resource in China with a wide distribution and simple associated components.It is an important raw material for the production of high-purity vanadium.The traditional sodium roasting process has the disadvantages of low vanadium recovery and serious environmental pollution,and has been classified as a phase-out technology.Sulfuric acid aging-water leaching and oxygen pressure acid leaching vanadium processes have the advantages of high vanadium recovery rate?cleanliness and environmental protection,and have received extensive research and attention in recent years.However,the iron in the vanadium ore of the stone coal enters the acid leaching solution with vanadium during the acid leaching process,resulting in a higher iron ion concentration in the leaching solution,which affects the recovery rate of vanadium and the purity of the vanadium product.To understand the leaching behavior of vanadium and iron during sulfuric acid aging-water leaching and oxygen pressure acid leaching is of great significance for regulating the leaching of vanadium and iron.This article takes the stone coal vanadium ore in Tongren area of Guizhou as the research object,deeply characterizes the mineralogical characteristics of the Tongren stone coal vanadium ore,focuses on the change of vanadium occurrence status during the sulfuric acid aging process of the Tongren stone coal vanadium ore,and analyzes the sulfuric acid aging material water.The leaching rules of vanadium and iron during leaching,Based on the above studies,this paper also discusses the selective leaching of vanadium and iron during the oxygen pressure acid leaching process of copper kernel decarburized stone coal,and explores the vanadium and iron Leaching mechanism.The paper has made the following progress:(1)The mineralogical characteristics of Tongren stone coal-vanadium ore were characterized.The results show that the Tongren stone coal-vanadium mine is a primary type coal mine,and the V2O5 grade is 0.80%,which is higher than the industrial mining boundary grade.The Fe2O3 content is 3.48%,which is 4 times the V content.84.10%of vanadium exists in silicate minerals in the form of V(?),mica,feldspar,pyrite,hematite,and vanadium in iron oxides,other minerals and organic matter are 8.80%,4.50%and 1.76%,the vanadium in the adsorbed state and calcite is less than 1.00%.(2)Exploring the change of vanadium occurrence state of Tongren coal-vanadium ore during sulfuric acid ripening.The results show that sulfuric acid curing can destroy the lattice structure of mica,iron oxide,calcite and other minerals,release vanadium and associated elements present in the above minerals,and simultaneously convert to soluble KV(SO4)2,KFe(SO4)2 and KAl(SO4)2.In the particle size of 160?250 mesh,the sulfuric acid addition amount is 32.46%,the curing temperature is 200?,the aging time is 50min,the water mixing amount is 1.00%,the leaching temperature is 50?,the leaching time is 2h,the liquid-solid ratio is 1.6:1.0,etc.The leaching rate was 86.65%,the leaching rate of Fe was 85.79%,and the leaching rates of V and Fe were basically the same.(3)Discussed the thermodynamics of oxidative decomposition of stone coal vanadium ore in H2SO4-O2 system.By analyzing the thermodynamic trends of possible reactions such as mica,pyrite and hematite in the H2SO4-O2 system,it is clarified that pyrite and hematite can be converted to KFe3(SO4)2(OH)6 under acidic conditions,under certain conditions.It can be submerged into the slag to achieve V and Fe separation.(4)The oxy gen leaching effect of Tongren stone coal vanadium ore and decarburized stone coal was compared.The results show that the decarbonization of stone coal is helpful for the separation of V and F.Under the optimal conditions such as leaching temperature of 210?,leaching time 2h,sulfuric acid concentration 18.60wt.%,Liquidsolid ratio 1.8:1.0,oxygen partial pressure 2MPa,and K2SO4 addition amount 7.00wt.%,The leaching rate of V is 83.67%,The leaching rate was 8.07%.Higher sulfuric acid concentration and leaching temperature are not conducive to the formation of KFe3(SO4)2(OH)6,resulting in a higher iron ion concentration in the leaching solution.