| Lead-acid battery as an important energy battery has been widely used in all aspects of society,because it contains a large number of metal lead compounds and sulfuric acid,scrapped if not properly disposed of it will cause resource waste and environmental pollution problems.At present,the lead smelting process mainly adopts fire method and wet fire combined technology.Although the emission of sulfur oxides has been largely improved,problems such as high energy consumption and large scale,large amount of lead-containing fly ash and waste residue have not been effectively controlled.However,the main current wet lead refining processes are characterized by a large amount of chemical reagent consumption,long process flow and high operating costs.In this paper,a process of direct electrolysis of lead paste from waste lead-acid battery in acidic electrolyte was proposed.Through experimental study and scientific analysis,the process parameters were optimized to recover metal lead from waste lead-acid paste and recover high concentration of sulfuric acid at the same time.The research on the recovery of metal lead in waste lead-acid batteries and the reuse of waste acid can effectively avoid the harm of hazardous waste to human body and environment.To effectively improve electrolysis efficiency and lead recovery rate in the wet electrolysis,reduce energy consumption of the electrolysis,the design of the horizontal plate solid electrolytic device,uses the sulfuric acid electrolyte to electrolysis of lead paste,was created and studied th eeffects of the amount of lead paste,current density,sulfuric acid electrolyte density and plates distance on electrolytic power consumption and efficiencyThe test results showed that the electrolytic efficiency was the highest when the amount of waste lead paste was 30g,the current density was 637A/m~2,the sulfuric acid electrolyte density was 1.1g/cm~3-1.2g/cm~3,and the distance between anode and cathode plates was10mm.In the experiment of recovering high concentration of sulfuric acid,the influence of the amount of lead paste,electrolysis time and initial acid concentration on the concentration of sulfuric acid recovered at the end was studied by controlling single factor variable.The results show that,due to the acid-producing reaction and the concentration of electrolytic water in the process of electrolytic waste lead paste,the sulfuric acid density shows a continuous rising trend in the process.However,due to the dynamic change of conductivity,when the initial densiity of sulfuric acid is higher than 1.20 g/cm~3,it cannot maintain a long-term and significant concentration increase.Electrolysis of waste lead paste within the initial sulfuric acid density of 1.10g/cm~3-1.20g/cm~3 can maintain the steady rise of sulfuric acid concentration in the whole process of electrolysis,and ensure the high efficiency of electrolysis of metal lead.The obtained sulfuric acid concentration density is greater than1.20g/cm~3,which can be directly used for the manufacture of lead-acid battery.At the same time,it was found that the density of waste acid in the original lead-acid battery was about1.105 g/cm~3-1.17 g/cm~3,and the density of waste acid collected after disassembly and washing was even lower than 1.14 g/cm~3,which could be used back in the electrolysis process and further concentrated to improve the concentration.Therefore,in order to ensure the high efficiency and low energy consumption of metal lead recovery,as well as the recovery of high concen tration of sulfuric acid,the best process parameters are the amount of lead paste added of 30g,the current density of 637 A/m~2,the distance between anode and cathode plate is 10mm,the sulfuric acid density is in the range of1.10 g/cm~3-1.20 g/cm~3,the energy consumption can be controlled below 220Kgce/t lead paste,and the lead recovery rate is about 98%.The detection results of lead products show that electrolytic lead has a good crystallization state,purity as high as 99.7%,recovery acid concentration reaches the manufacturing standard of lead acid battery electrolyte,has a high economic value.Direct electrolysis recycling metal lead and sulfuric acid from waste lead acid battery in the technological process is simple,it is energy conservation and environmental protection,at the same time of efficient recovery of metallic lead,comprehensive utilization of waste sulfuric acid with the recycling concentrated sulfuric acid,have remarkable economic benefits and significant ecological value,provides a new way for lead-acid battery recycling use and waste treatment and disposal of hazardous waste. |
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