Study On Comprehensive Recycling Of Vanadium Residue From Shihe Coal

The procedure of vanadium extraction from stone coal will result in generous stone coal tailings which leads to serious environmental problems and security risks.The most effective way to solve this problem is the comprehensive utilization of Stone coal tailings. This research discusses three methods to comprehensively utilize Stone coal acid-leaching vanadium slag,detemine the optimized condition,Main contents and results of the research are as follows:Stone coal acid-leaching vanadium slag was used to prepare portland cement clinker. Clinker of 11 different kinds of compositions was calcined at 1350,1400 and 1450℃. Differential thermal analysis(DTA)was used to study the formation mechanism of acid-leaching calcined clinker. X-ray diffraction(XRD) was used to determine the composition of clinker and hydrated cement. Crystallographic structure was confirmed by scanning electron microscope(SEM). The results demonstrate that adopting vanadium slag improves clinker’s burnability and contributes to the formation of clinker minerial. With 20% vanadium slag addition, the clinker was produced froms along with less than 1.0% free CaO. The hydration heat of cement meets the National Standards.Stone coal acid-leaching vanadium slag was used to prepare cement admixture. The composition of hydrated cement was determined by X-ray diffraction(XRD). Crystallographic structure was confirmed by scanning electron microscope(SEM).The results of mixed material experiment show that the stone coal acid-leaching vanadium slag is an active material of cement, when mixed percentage of stone coal acid-leaching vanadium slag changes between 10%-25%, the compressive strength of earlier experimental cement samples is lower than ordinary portland cement, while other performance indicators are approximately close, and the strength of the former cement can reach 32.5R degree,which meets the industrial standards.White carbon black was prepared by precipitating from stone coal acid-leaching vanadium slag incinerating at 750℃. Which can obtain products of white carbon black with large specific surface area. Silicon is dissolved into aqueous solution by alkali, and from the stone coal acid-leaching vanadium slag. After stirring, adjusting pH, precipitating still, filtering,washing and drying, the white carbon black is made. The optimum leaching conditions are as follows: sodium hydroxide concentration of 6mol/L, solid-liquid ratio of 1:4, leaching temperature of 95℃ and the reaction time of 4h. The production rate is 73.1%, the recovery rate of silicon is 43.2%, the content of silicon dioxide is 91.2%, and the products meet industry standards.This study indicates that stone coal acid-leaching vanadium slag can be used as portland cement clinker and cement admixture,as well as raw material of the precipitated silica. It will improve the resource recovery,in the meantime,avoid pollution. The results of the study can provide novel ideas and theoretical foundation related to the waste treatment of stone coal acid-leaching vanadium slag.