Study On Recovery Of Platinum And Rhenium From Spent Catalysts

Platinum-rhenium catalysts are widely used in industrial catalysts because of its long life,the spent catalysts which contain high levels of platinum and rhenium is an important secondary resource of platinum and rhenium.Therefore,recycling and reuse of the spend catalysts have great significance.In this paper,?-Al2O3 supported platinum and rhenium catalysts were used as the research objects.Comparing the roasting-acid leaching-adsorption separation of platinum and rhenium,roasting-preimpregnation rhenium-acid immersion platinum,and direct acid-activated carbon adsorption platinum and rhenium,and found which one is the best for platinum and rhenium recovery.This paper investigated the influence of calcination temperature and time on the composition of the catalysts.The optimum technological conditions were obtained as follows:the calcination temperature was 550?;the calcination time was 2 h;the mass fraction of carbon dropped to 0.39%;the mass fraction of sulfur was 0.036%,and the volatilization loss of rhenium was low.The amount of concentrated sulfuric acid required to dissolve spent catalysts after roasting was 1.5 mL/g;the solid-liquid ratio was 1:6;the reaction temperature was 105?;the reaction time was 3 h,and the base dissolution rate was 95.55%.Dissolution system continued to add hydrochloric acid 0.025 mL/g,8%sodium chlorate was 0.5 mL/g,the temperature was 90?,the reaction time was 1 h;the leaching rate of platinum was 99.6%,and the leaching rate of rhenium was 99.7%.The spent catalysts after roasting,the amount of ammonia was 0.5 mL/g;the solid-liquid ratio was 1:8;the leaching temperature was 70?;the time was 1h and the rhenium leaching rate was 78%.Pretreatment temperature between 100 and 550?,the higher the temperature,and higher leaching rate of rhenium.Resin adsorption and desorption experiments showed that the adsorption time was 20 min;the adsorption temperature was 60?;pH was 0.9;the saturated adsorption capacity per ml of resin for platinum was 16.35 mg;the saturated adsorption capacity for rhenium was 37.33 mg.When the analytical solution was 10%NaOH and the amount of 2 times the volume of the resin,the desorption of platinum was completely,and the desorption rate of rhenium could reach 95%;while continuing to increase the concentration of the desorption,the rate was not affected.The results of acid-solubilization experiments show that the leaching temperature was 105?;the time was 3 h;the solid-liquid ratio was 1:6,and the concentration of H2SO4 is 1.25 mL/g.Under this condition,the base dissolution rate was 99.5%.The amount of activated carbon for per gram of spent catalysts acid solution is 0.03 g,and adsorption time was 3 h,the content of platinum and rhenium in the solution was lower than 1 ppm.