Study On Technology Of Extracting Vanadium By Sodiumziation Melting Of Vanadium-titanium Magnetite

Vanadium-titanium magnetite is a kind of complex ore,with symbiosis of multi-metal elements,existence of multiple ore phases,and high comprehensive value and great potential for utilization,among which iron,vanadium and titanium are all important strategic resources.The contradictions in environmental load,process length and economic efficiency with resource utilization are common in the current process.In order to efficiently use the valuable metals,especially the rich vanadium element of a vanadium-titanium magnetite in a mining area in South Africa,the new coupling process of vanadium-titanium magnetite sodiumization-reduction-fusion is carried out that combines the sodiumization of vanadium,the reduction of iron,and the melting of the system in one step.Meanwhile,the conversion of vanadium in the slag to water-soluble sodium vanadate is realized,and the vanadium and titanium can be efficiently separated in the subsequent process by only water extraction of vanadium.Thus the thermodynamic analysis are carried out in the coupling process,a systematic study of effects of the anthracite blending amount,Na₂CO₃ blending amount,temperature,and roasting time on the degree of reduction and melting,rate of vanadium distribution,and yield of iron and vanadium element of the vanadium-titanium magnetite coupling process are carried out.The results obtained are as follows:?1?Based on the thermodynamic analysis of the possible reactions during the sodiumziation-reduction-fusion of vanadium-titanium magnetite in South Africa,the thermodynamic conditions of the oxidization and sodiumziation between vanadium oxide and Na₂CO₃ to form water-soluble vanadate and the reaction of reduction of iron oxide to form metallic iron can be satisfied.It must be emphasized that Vanadium compounds are easily reduced by solid carbon after being oxidized to V⁵⁺compounds.Therefore,during the smelting process,the reduction efficiency determined by the anthracite blending amount,the temperature,and the reaction time has an important influence on the distribution of vanadium.?2?It is obtained through single-factor variable experiments that increasing the temperature can promote the reduction melting degree of the reduction melting,but it is to the disadvantage of the enrichment of vanadium element in the slag.Under the conditions of anthracite blending amount of 25%and 35%,the vanadium element is highly enriched in the slag.But the degree of iron oxide reduction is low under the condition of low anthracite blending amount,and the slag and iron separation of the system is not ideal under the condition of high anthracite blending amount.Increasing the amount of Na₂CO₃ can promote the reduction of fusion.As the amount of Na₂CO₃increases,the degree of sodiumziation and extraction also increases.?3?Based on the Box-Behnken principle,an experiment is designed to study the main influencing factors of vanadium element distribution rate,leaching rate and sodiumation leaching index in the coupling process by response surface methodology.The corresponding mathematical model is obtained.It is concluded that the significance of the effect on index in sodium leaching is,from large to small,amount of Na₂CO₃>temperature>amount of anthracite.?4?According to the optimal value of the model of index of sodiumation leaching,when the index is at the optimal response level,the optimal parameters are obtained:anthracite blending amount is 25.00%,Na₂CO₃ blending amount is 58.29%,temperature is 1251?,and the sodium leaching index response value is 90.19%.Experiments are performed under the optimal parameters,the vanadium sodium leaching index is 87.17%.At the same time,the iron recovery rate is 86.21%,and titanium element is enriched in slag.