Extracton Of Valuable Scandium Component From Baotou Rare Earth Tailings

Baotou rare earth tailings have a lot of scandium resources.It is an ideal raw material for scandium and has a very considerable economic value.Baotou rare earth tailings were comprehensively analyzed by means of chemical analysis,XRD,and SEM.The results show that the main mineral of earth tailings arc silica,magnetite,sodium amphibole and sodium pyroxene.Scandium content is small and dispersed.There is no obvious scandium-containing phase.Scandium is isomorphism with the occurrence of sodium amphibole,sodium pyroxene.Therefore,It is difficult to extract scandium from baotou rare earth tailings.First of all,the rare earth tailings to the separation of magnetic separation,the results show that in two different magnetic field strength 50 mt and 243 mt,In magnetic and non-magnetic tailings,the content of scandium were similar,so two parts are necessary to extraction of scandium.Combined with the Physical properties and chemical properties of the minerals.Three process schemes on the extraction of scandium from rare earth tailings were proposed,different conditions of experiment on leaching ratio of scandium were studied.Studying the process of separating scandium from tailings by alkali roasting-leaching method:Some conditions were studied to determine the optimal leaching conditions.They are calcination temperature,ratio of concentrate to alkali,reaction time and so on.We obtained that the better experimental conditions ratio of alkali to ore is 1.5:1,the calcination time is 2.5h,the calcination temperature is 500? the concentration of hydrochloric acid is 4mol/L,the leaching ratio is 1:3,leaching time is 4h,the leaching rate of scandium is 83.4%.After alkali calcination,the silicate structure in the tailings was turned into NaFeO2 and other silicate material,which is beneficial to the subsequent leaching of scandium.The process of separating scandium from tailings by chloridic roasting-leaching was studied,The effects of CaCl2 dosage,calcination time,calcination temperature and some other conditions on the scandium leaching rate were studied.The better schemes of leaching scandium arc amount of calcium chloride of 60%,calcination temperature of 850? and calcination time of 2h,concentration of hydrochloric acid of 4mol/L,leaching time of 4h and the solid-liquid ratio of 1:3.The leaching rate of scandium is 86.1%.After the chlorination,the silicate structure in the tailings was turned into calcium silicate,and the scandium element content increased,which laid a foundation for subsequent mention of scandium.The process of separating scandium from tailings by deoxidizing chlorination-leaching was studied.The effects of chlorination temperature,carbon ratio,chlorination time and chlorine flow rate on the scandium leaching rate were investigated.The berrerl conditions of chlorination process are temperature of 800?,chlorine flow of 60 ml/min,carbon content of 25%and time of 2h.The optimal conditions of the leaching process are the hydrochloric acid concentration of 2 mol/L,the solid-liquid ratio of' 1:2.the leaching temperature of 60? and the leaching time of'4h.Under the optimal conditions,the leaching ratio of scandium is 89.1%.Chlorinated tailings convert into sodium chloride or other chloride.Scandium content is much higher than rare earth tailings.Leaching residues are mainly silicon dioxide,sodium pyroxene and some other silicate.The research results indicate that there process schemes are feasible,in which,the method of reducing chlorination is the best.There process schemes can provide a reference to the rational utilization of Baotou rare earth tailings.