Research On Thchnology For Separation Of Vanadium And Chromium From Sulfuric Acid By Solvent Extraction

With the development of the steel industry,vanadium,which is called "modern industrial MSG",is in short supply.The source of vanadium continues to be expanded,but it is a hard problem to purify vanadium from the vanadium chromium slag continuously.The accumulation of vanadium chromium slag not only has an impact on the environment,but also cause waste of resources.In the past few decades,the technology of purifying vanadium from vanadium chromium slag has been continuously improved such as chemical precipitation method,sodium roasting-water immersion method,ion exchange method and sintering-blast furnace smelting method.In recent years,environmentally friendly solvent extraction method and emerging roasting systems also appear.In general,there is a large market in this direction.In this paper,based on the O216,the vanadium and chromium in the slag was separated and purified by solvent extraction method.The whole process was in line with the environmental protection concept,and the purity of products was high.To analysis the content of metal ion,a combination of conventional redox titration and high frequency inductive plasma atomic emission spectrometry was used.First of all,a series of extractants was optimized,and the best one in them was O216 according to various indexes.The optimal extraction conditions are optimized as follows: 40% O216-5% 1#cosolvent-55% 3# thinner was as the extractant solution,the p H of the leachate was adjusted to 0.3,the A/O was 1.5,the extraction temperature was 30 °C,the extraction time is 5 min.The single-stage extraction rate was near100%,and the saturation capacity was determined to be 15.53 g/L.The loaded organic was washed three times,and then the stripping experiment was optimized and the single-stage stripping rate reached 100%.The stripping solution was used to produce chromium oxide.The product was analyzed with ICP and XRD.The purity of the chromium oxide is 91.22%.Next,the optimal extraction conditions of purifying vanadium are optimized as follows: 40% O216-40% 1#cosolvent-20% 3# thinner was as the extractant solution,the p H of the leachate was adjusted to 1.5,the O/A was 3,the extraction temperature was 30 °C,the extraction time is 7 min.The single-stage extraction rate was about70%,and the saturation capacity was determined to be 6.05 g/L.After 12 rounds of6-stage countercurrent extraction,the extraction rate wa above 98%.The loadedorganic was washed three times,and then the stripping experiment was optimized and the single-stage stripping rate reached 100%.The stripping solution was used to produce vanadium oxide.The product was analyzed with ICP and XRD.The purity of the chromium oxide is 99.98%.The mechanism of extracting vanadium and chromium with O216 was studied by coordination theory,equimolar concentration method,slope method and infrared spectroscopy.The extraction equations were obtained,which can provided a theoretical basis for the process.The prospect of vanadium-chromium slag vanadium extraction technology was predicted.After market economy analysis,gross profit was150,000 yuan/ton,and finally SWOT analysis was carried out.The innovation of this paper is mainly the self-synthesis of a new type of extractant,which has excellent extraction performance.With adjusting the p H,vanadium and chromium can be separated thoroughly.At the same time,the extractant is economical and environmentally friendly.The highlight of the paper is the study of new extractant mechanisms and the development of new extraction systems..