Study On Cooper-containing Waste Catalyst For Recovery Utilization

In this study, cooper-containing waste catalyst was treated by pyrolysis-ammonia leaching process. The process conditions were optimized and Cu2 O was prepared by evaporating ammonia reduction. First, the effects of heating rate, final temperature, residence time and air flow rate on pyrolysis were studied in tubular furnace. And then, the pyrolysis kinetics of cooper containing-catalyst was investigated by using TG-DTG at various heating rates and single heating rate. And the exhaust gas of the pyrolysis be processed by the alkaline absorption method, and the four kinds of absorption fluid, ratio of ammonia quality, exhaust velocity, the absorption liquid temperature were discussed. And conditions of ammonia leaching were optimized from ammonia temperature, ammonia solution, molar ratio of ammonia-ammonium, stirring rate,particle size. And the study of kinetics of ammonia leaching obtained the activation energy E and the reaction order n, at last Cu2 O was prepared by evaporating ammonia reduction. The optimum pyrolysis parameters result showed that: heating rate of 20℃·min-1,final temperature of 600℃,residence time of 90 min and the air flow rate of 3.0L·min-1. The process of decomposition included four stages, and the activation energy in the four stages were determined respectively 16.181 k J · min-1, 43.841 k J ? mol-1, 90.561 k J ? mol-1,52.313 k J ? mol-1, and pre-exponential factors 4.696×109s-1, 1.457×1013s-1,8.662×1012s-1, 4.939×105s-1. The decomposition action of the first stage controlled by the chemical reaction, belonged to Reaction order equation with f(α)=(1-α)2, g(α)=(1-α)-1-1, the second stage controlled by the nucleation and growth(n=3), belonged to Avrami-Erofeev equation with f(α)= 1/3(1-α)[-ln(1-α)]-2, g(α)=[-ln(1-α)]3, and the third and forth stages controlled by nucleation and growth(n=4), belonged to Avrami-Erofeev equation with f(α)=1/4(1-α) [-ln(1-α)]-3, g(α)= [-ln(1-α)]4. The best experimental condition of alkaline absorption were as follows: the ratio of ammonia quality was 1:2, the absorption rate was 0.6L·min-1, the absorption liquid temperature was 50℃and the rate of absorption was 99.95%. The optimum conditions to ammonia leaching were as follows: the NH4Cl-NH3-H2 O solution as leaching solution with4 mol · L-1of total ammonia concentration, molar ratio of ammonia-ammoniumwas 1:4, stirring rate was 300 r · min-1, particle size was 29.43μm, and the activation energy of ammonia leaching was 7.59 kJ·min-1,the reaction order was0.6158. The quality of Cu2 O product can meet the first grade standards of HGT2961-2010, and the yield was 97%.