Study On Resource Utilization Of Petrochemical Reforming Spent Catalyst

The spent catalyst produced in the petrochemical reforming process contains a variety of heavy metals,which is regarded as a kind of hazardous waste.The petrochemical enterprises in the Dongying Port Economic Development Zone produce a large amount of spent catalyst every year,and their disposal capacity is seriously insufficient.According to the requirements of a disposal center for hazardous wastes and local disposal in a disposal center in Dongying Port,this paper used the sodium roasting-water immersion method to carry out resource utilization and localization disposal of petrochemical reforming spent catalysts.The suitable separation and recovery conditions of valuable molybdenum and nickel in the catalyst were evaluated for the social and economic benefits of the study.The main research contents and conclusions are as follows:Firstly,the test methods of the main elements in the experiment were listed.The chemical and instrumental methods were used to analyze the composition of the reformed spent catalyst from a chemical enterprise in Dongying Port.By comparing the XRF test method with the chemical method for the spent catalyst,the test results of the target element nickel and molybdenum determined that the content of nickel in the raw material was in the range of 2.8%~3.2%,and the content of molybdenum was in the range of 12.5%~14.5%.Secondly,in the recovery experiment of molybdenum,the leaching rate of molybdenum was used as the indicator.The influence of various factors on the leaching rate of molybdenum was investigated by single factor experiment and orthogonal experiment.The optimum leaching conditions for molybdenum were as follows: calcination temperature 800 °C,the calcination time 1 h,the material ratio1:12,the leaching temperature 100 °C,the leaching time 2 h,and the solid-liquid ratio1:10.Under this condition,the leaching rate of molybdenum can reach over 99%.By adjusting the p H,most impurities have been removed and calcium salt was added to the filtrate to obtain calcium molybdate precipitate.The composition analysis of calcium molybdate precipitation shows that the content of molybdenum was more than40%,the content of calcium was less than 24%,and the remaining impurities were notmore than 2%,in line with the requirements of the secondary industry standard UMTY-4523-65 ROC after experimental verification.Thirdly,in the recovery experiment of nickel,the leaching rate of nickel was used as the indicator.The effects of various factors on the leaching rate of nickel were investigated by single factor experiment and orthogonal test.The optimum leaching conditions for nickel were as follows: sulfuric acid concentration 30%,the solid-liquid ratio 1:5,the acid immersion time 1 h,and the acid immersion temperature 70 °C.Under this condition,the nickel leaching rate can reach 94%.By adjusting the p H,most impurities have been removed and carbonate was added to the filtrate to obtain nickel carbonate precipitation.The composition analysis of nickel carbonate precipitation shows that the content of nickel was more than 45%,and the content of iron was less than 0.01%,which conforms to the industrial standard GB/T.Requirements for 26521-2011 after experimental verification.Fourthly,a brief analysis of the kinetics of the leaching process of molybdenum and nickel in the experiment was carried out.It was determined that the optimal leaching particle size of molybdenum was in the range of 74-100 ?m,and the leaching process of molybdenum was a mixed control kinetic model,the equation was (?);Stirring speed has little effect on nickel leaching and the nickel leaching process was a diffusion controlled kinetic model,the equation was (?).Finally,in practical application,the recovery of reforming spent catalyst makes the hazardous waste only flow and digest in the producing enterprises and industrial parks,avoids the risk brought by transfer disposal,and conforms to the principle of insitu disposal;The recycling of metals was of great significance for resource conservation and meets the disposal principles of hazardous waste resources.The economic analysis was carried out using the economic model of maximizing benefits.The economic simulation curve showed that with the support of national policies,the first year of project simulation operation can generate 681,300 yuan.An assessment using a clean production audit approach yields economically viable conclusions.