Study On The Overall Recovery Process Of Several Precious Metal Waste Liquids By Modified PVC Resin

This article focuses on the research on the overall recovery of precious metals in the three waste liquids produced by a factory in the actual production process,and proposes a recovery and enrichment process that combines the advantages of environmental protection and energy saving,high economic benefits,and fast processing efficiency.The main content is divided into the following parts:1.In the introduction,first introduce the properties of precious metals Pt,Pd,Rh,Ir and their applications in the fields of biology,medicine and catalysis.Secondly,it summarizes the methods of enriching precious metals such as Pt,Pd,Rh,Ir in the actual production process,and summarizes the research status and development process of enriching precious metal ions with resins.Finally,according to these application examples,in view of the actual situation of the factory waste liquid,a test plan for using modified PVC resin to enrich the precious metals in the waste liquid was designed.2.According to the experimental plan,the influence of control variables such as p H value,temperature,dosage,time,interfering ions,etc.on the adsorption of Pd(Ⅱ)by the two modified PVC resins was successively explored.Using SEM,elemental analysis and other analytical methods to characterize and analyze the modified PVC resin,the optimal reaction conditions of the two imidazole-modified PVC resins were obtained,and it was found that the modified PVC resin [PVC-im]Cl had an effect on Pd(Ⅱ)The enrichment effect is better than [PVC-Nim]Cl.These conclusions laid a theoretical foundation for the subsequent enrichment of precious metals in the actual factory waste liquid.3.Aiming at the three waste liquids of a certain factory,a process plan for enriching precious metals in the waste liquid was designed.Since the precious metal waste liquid belongs to a complex system with high salt content,high acidity,and different precious metal contents.Firstly,sodium dimethyldithiocarbamate was selected as a pretreatment precipitating agent,and the optimal p H,temperature,dosage and time conditions for precipitation of precious metals were explored.Time conditions.Secondly,the modified PVC resin [PVC-im]Cl was selected as the adsorbent to enrich the precious metals in the waste liquid after pretreatment,and the optimal p H value,temperature,dosage,and time conditions during adsorption were explored.After the workshop’s pilot test,it was found that there was another waste liquid containing organic matter that could not meet the discharge standard.Therefore,a packed column experiment was carried out on this waste liquid,and the filling material was modified PVC resin [PVC-im]Cl.The effect of the solution flow rate and the column height of the packed column on the adsorption of precious metals was explored,and the concentration of other interfering ions in the waste liquid was detected.The results showed that [PVC-im]Cl could not adsorb other metal hydrated positive ions and could only be combined with chlorine The platinum group precious metals existing in the form of anions can be quantitatively enriched and recovered,and the treated precious metal waste liquid can be discharged up to the standard.