Research On Vanadium Extraction From Vanadium-rich Resources By Selective Chlorination

Vanadium resources are abundant in China. Vanadium-bearing titanomagnetite in Panxi area has proven reserves of9.664billion tons. Vanadium-bearing titanomagnetite is a kind of multielements-coexistent (such as ferrous, vanadium, and titanium) iron ore with a high utilization value. About88%world annual vanadium production is refined from vanadium slag which is one of product of the smelting process of vanadium-bearing titanomagnetite. Therefore, vanadium-bearing titanomagnetite is the main source of vanadium extraction.The traditional process of vanadium extraction from vanadium-rich resources not only is low in recovery ratio, but also causes serious environmental pollution and resource waste. This thesis is based on the theories of thermodynamic calculations and the smelting process of vanadium extraction, proposes a novel selective chlorination of vanadium technology with high material adaptability, low energy consumption and less pollution. Based on the two different vanadium extraction methods,(1) roasting of vanadium-bearing titanomagnetite with rich oxygen-cold forming-extracting vanadium by selective chlorination and (2)vanadium slag cold forming-extracting vanadium by selective chlorination, some research achievements are obtained as follows.(1) The thermodynamic analysis of chlorination vanadium extraction by chlorination from vanadium-bearing titanomagnetite and vanadium slag shows that vanadium extraction by chlorination, based on thermodynamic calculation, from vanadium-rich resources is feasible. The higher valence of vanadium in vanadium resources, the easier for the selective chlorination of vanadium.(2) The thermodynamics analysis on relative system of compounds in vanadium resources shows that the chlorination order of various metal oxides in the chlorination process is K2O> Na2O> CaO>MnO>V2O5when FeCl2or FeCl3is selected as the chlorinating agent and the experimental temperature is higher than800K; The stable region of VOCl3will shrink gradually with the rising of the chlorination temperature, and the stable region of VOCl3enlarges with the reduction of its partial pressure.(3) These two vanadium extraction methods show that a higher ratio of vanadium extraction is reached using FeCl3than FeCl2as chlorinating agent under the same experimental conditions; The higher ratio of chlorinating agent, the higher ratio of vanadium extraction; Oxygen atmosphere is beneficial to a higher ratio of vanadium extraction; When vanadium-bearing titanomagnetite is used as the raw material, the ratio of vanadium extraction will reach to32%if chlorinating agent ratio is1:2, chlorination temperature is1100K, and chlorination time is2hours under oxygen atmosphere; When vanadium slag is used as the raw material, and the ratio of vanadium extraction will reach to57%if chlorinating agent ratio is1:2, chlorination temperature is1000K, and chlorination time is2hours under oxygen atmosphere.