钒渣中钒铬提取技术研究进展

钒钛磁铁矿中的有价伴生元素为钒、铬,在冶炼钒渣过程中,同时被氧化进入钒渣,得到含铬型钒渣。由于钒的提取价值较高,目前国内外钒化工产品生产工艺大多针对钒渣中的钒进行回收。针对钒渣多次焙烧钒回收率仍低于80%,且重要伴生重金属铬基本不能被提取的现状,中科院过程所与承钢联合开发的钒渣新型反应介质——亚熔盐高效非常规介质将传统的焙烧工艺中的气固传质过程转化为液固传质过程,从微观介质上改变了钒渣焙烧过程中氧传质的问题,使尖晶石相的氧化分解过程在液相中发生,避免了烧结包裹问题,钒铬可以实现同步清洁高效提取。反应温度为200～400℃时钒回收率由传统工艺的80%提高到95%以上,铬由基本不回收提高至回收率高于85%以上,且可以实现尾渣的综合利用。

Research Progress of Extraction Technology for Vanadium & Chromium from Vanadium Slags

Vanadium and chromium,coexisted in vanadium-titanium magnetite,are valuable elements.In the process of smelting vanadium slag,V and Cr were oxidized,getting the vanadium slag containing Cr.Because the vanadium is more valuable than other elements in vanadium slag,most of the production technology for chemical products of vanadium is for the recovery of vanadium.However,the leaching rate of vanadium,after roasting-leaching several times,was less than 80%.Moreover,the chromium couldn't be extracted.Aiming at above problems,the novel reaction medium for vanadium slags is explored by IPE,ACS and Chengde Iron&Steel Group Co.,Ltd..The mass transfer process of gas-to-solid in roasting process was converted to mass transfer process of liquid-to-solid in the novel reaction medium.The mass transfer process of oxygen was improved excellently from micro medium.Thus,the oxidation and decomposition process of spinel phase was presented in liquid medium,which prevented the occurrence of sintering and parcel phenomenon.By this method,the Vanadium&Chromium can be simultaneously extracted with clean and efficiency.When the reaction temperature is between 200℃ and 400℃,the recovery rate of vanadium is increased from 85%to 95%comparing traditional process and the recovery rate of chromium is more than 85%.Besides,the tailings from this process can be utilized synthetically.