A Novel Method For Comprehensive Utilization Of Multiple Metals From Stone Coal Containing Vanadium And Molybdenum

As the separate deposits of vanadium,the carbonaceous shale (stone coal) has accountedfor most of the domestic reserve of vanadium.At present, a variety of metal elementsassociated have been found varying in degree in stone coal.If these metal elements could berecycled in the process of vanadium recovery,that would enhance the comprehensiveutilization rate of stone coal on one hand,on the other hand,relieve the consumption of relatedrich ore.In the present study,the stone coal mined from Shanxi province,is such a kind of orewith high comprehensive utilization value,that is mainly composed of vanadium and a certaingrade of molybdenum.Focus on the peculiarities of such a stone coal,a novel method forrecovering vanadium, molybdenum from it was developed,which contains a series ofprocedure of magnetic separation, roasting, flotation, two stage leaching, extraction,regrindand recleaning.Results of magnetic separation and reduction roasting procedures showed that bycontrolling the yield of concentrate in30.6%,67.73%iron，29.42%vanadium and25.04%molybdenum could be recovered after the stone coal was separated at the magnetic fieldintensity1.2T;After the concentrate of magnetic separation was roasted by conventional roastmethod at650℃together with5%carbon for2h,the consumption ofvitriol due to thehematite dissolving would lower about6%in the process of leach.The experiments on flotation showed that the suitable conditions of flotation weregranularity of concentrate was-200mesh85.5%,sodium sulfured800g/t, butyl xanthic acid50g/t, Dithiophosphate BA400g/t, flotation time30min and ore pulp concentration30%.Therecovery rates of flotating were vanadium44.59%, molybdenum62.77%, calcium10%andiron21.11%.Results of leaching procedure showed that86.45%vanadium and94.70%molybdenumcould be extracted after two-step leaching.The optimized leaching conditions of first phasewere as followed: sulfuric acid-raw ore ratio30%, sodium chlorate-raw ore ratio3%,leachingtemperature95℃, leaching time20h at liquid-solid mass ratio1:1;and the optimized leachingcondition of second phase were as fowllow: leaching temperature95℃,leaching time20h atliquid-solid mass ratio1:1.After the process of mineral separation-roasting-two stage leaching,the mineralseparating recovery of vanadium and molybdenum from raw ore reached upto,respectively,74.01%and87.81%.The leaching efficiencies of vanadium and molybdenum from concentrate products reached up to,respectively,86.45%and94.70%.So,it wascorrespond to that63.98%vanadium and83.16%molybdenum were leached from raw ore.In the metal recovery step from the filtrate containing vanadium and molybdenum,underoptimize conditions,both the extraction yield and stripping yield of vanadium andmolybdenum could reach up to99%;in the meanwhile,90%iron could be recovered after theleached residue which was-200mesh93%was separated at the magnetic field intensity0.12T.The grade of magnetic concentrate could reach up to52.3%. So,it was correspond tothat52.9%iron was recovered from raw ore.