Study On The Mechanism Of Stone Coal By Fluidized Roasting

Stone coal which is a unique vanadium resource has abundant reserves in ourcountry. Extraction of vanadium from stone coal is the most important means to thedevelopment and utilization of vanadium resources. At present the common processesof extraction of vanadium from stone coal still have many problems which mainlyinclude the high cost, low recovery rate and environmental pollution, etc. In order tomake the extraction of vanadium more efficient, low cost and clean, fluidized roastingof stone coal ore of Hubei was conducted to study the process of roasting reactionmechanism and simultaneously compare with the effect of static roasting.The result shows that0~6mm of Stone coal ore granularity is more appropriatefor the fluidized roasting pilot system used for the test. The leaching rate of vanadiumwas more than75.18%under the best condition of roasting for10min at800℃, andthen leaching with adding5%calcium fluoride and15%H2SO4for6h at98℃withsolid-liquid ratio of1.5mL/g. At the same time the loss rate of vanadium was only1.23%in the fluidized roasting pilot system.The existence of the carbon in the roasting process will inhibit the oxidation ofvanadium, but the heat generated by the combustion of carbon promoted the roastingprocess. And the time of decarburization and oxidation of vanadium in fluidizedroasting process is shorter. The degree of destruction of vanadium muscovite structureunder the condition of shorter roasting time and lower roasting temperature influidized roasting is more bigger than in the static roasting of longer roasting time andhigher roasting temperature. The vanadium of organic matter gets into the free oxide influidized roasting, most of the vanadium still exists in the muscovite type of silicateminerals. Under the action of acid leaching vanadium turned into the leach liquorbecause of the destruction of silicate minerals structure in fluidized roasting. Asmuscovite structure was not destroyed fully, a small amount of vanadium which stillexists in the muscovite type of silicate minerals is difficult to recycle.