The Research On The Mechanism Of Reduction Concentration Of Vanadium In V-bearing Stone Coal

Vanadium and its oxides have excellent physical and chemical properties,and are widely used in various industrial fields.Therefore,the recovery of vanadium is particularly important.Vanadium mainly exists in low-grade minerals,for example:more than 70% of vanadium resources in China consists in stone coal mineral.However,because of the mineral with low vanadium content,traditional wet methods cause a lot of questions,such as serious environmental pollution and difficult tailings treatment.Therefore,it is necessary to upgrading before the vanadium extracts from the mineral.In view of this,the typical stone coal mineral is served as the research object to study the occurrence of vanadium in stone coal ore and migration law of vanadium under the condition of autoreduction and modification reduction,in turn analyzing vanadium enrichment mechanism under reduction conditions,through method of high temperature reduction,using SEM,XRD and XRF analysis method.Based on the above research,the following results are obtained:V-bearing stone coal mainly consist of SiO₂,Al2O3,C,and a small amount of alkali metals and alkaline earth metal oxides.The main mineral phases in the stone coal are quartz,mica,and a small amount of FeS2,calcite and so on.Vanadium in the stone coal mainly consists in sericite.Reduction concentration of vanadium in stone coal is not obvious when the temperature is below 1200?.Under the condition of self reduction or addition carbon reduction,mica stone in stone coal decomposed above 1200?,and the vanadium resolving in the mineral phase was released,forming vanadium-iron alloy and V2O3.Two vanadium concentrating phases bring the difficulty of vanadium rich phase separation.Modified reduction was carried out at 1300?,the vanadium oxide was reduced to formate FeV alloy,and P and S entering the alloy.The degree of enrichment of vanadium in the alloy is about 70%,the content of magnetic part of V and Fe is not high,there is about 2.5-4.5% V2O5,after magnetic separation.The results of the study on the formation of vanadium concentration phase inmolten slag with Fe equilibrating shows that when the basicity is much than 1.5,the calcium silicate and RO phase precipitate during the cooling of molten slag.Most of the vanadium in the slag dissolves in two phase,dicalcium silicate?Ca2SiO4·mCa3?V,P?2O8?,and the rest of the vanadium exists in calcium ferrite phase.When the basicity is lower than 1.5,the formation of calcium silicate and calcium ferrite is inhibited,and the majority of vanadium in the slag concentrates in vanadium-iron spinel??Fe,Mg?O??Fe,V?2O3?phase.Joint vanadium enrichment experiments on stone coal containing vanadium and slag containing vanadium show: when the basicity is less than 1,the spinel containing vanadium does not produce or produce a few,spinel phase has lower vanadium content;when basicity is between 1-1.4,the spinel phase has a high vanadium content;when basicity is 1.5,there are two phases containing vanadium,the tow phases have lower vanadium content,the results are consistent with the thermodynamic results.The results provide theoretical support for the enrichment of vanadium from stone coal,and provide a new direction for efficient and low pollution vanadium recycling from stone coal containing vanadium.