Carbon Footprint Analysis And Carbon Emission Reduction Technology Of Lead Paste Regeneration Process

As an energy storage material,lead-acid batteries are widely used in the fields of automobiles,motorcycles,electric mopeds,communications,electric power,and national defense and military industries.There are more than 110 million scrap lead-acid batteries in my country each year,containing more than 3.5 million tons of lead.,Recycling the lead paste of used lead-acid batteries is the main way to realize the recycling of lead resources in my country.The traditional pyrometallurgical high-temperature smelting lead paste regeneration process has high energy consumption and heavy pollution.The development of"low temperature smelting or no smelting"clean production process to achieve pollution reduction,carbon reduction,energy saving and efficiency is an important guarantee for the sustainable development of my country’s recycled lead industry.Based on the research of sodium and ammonium carbonate pre-desulfurization low temperature smelting technology carried out by the research group in the early stage,this paper analyzes the carbon footprint of the process,finds out the feasible key links for further carbon reduction,and constructs the circulating pre desulfurization process of"carbonate lead paste desulfurization ammonia water absorption carbonate decomposition carbon dioxide carbonization ammonia lead paste desulfurization",To explore the feasibility of lead paste particles to enhance ammonia absorption of carbon dioxide and carbonized ammonia lead paste desulfurization,so as to provide technical support for carbon emission reduction in lead paste regeneration process.First,the thesis uses the life cycle method to compare the carbon footprint of the lead products produced by the three processes of sodium pre-desulfurization low-temperature smelting,ammonium pre-desulfurization low-temperature smelting,and high-temperature smelting.The results show that the carbon emissions of the lead paste sodium method and the ammonium method pre-desulfurization-low temperature smelting process are far lower than the carbon emissions of the high temperature smelting method.They are indeed clean processes and should be vigorously promoted and applied.But at the same time,in the sodium and ammonium pre-desulfurization low-temperature smelting processes,the carbon emissions generated by the decomposition of carbonates account for 17%and 34%of their carbon footprint,respectively.There is a lot of room for carbon emission reduction,which is a further step.The focus of carbon reduction.Secondly,the thesis studies the feasibility of lead paste particles to enhance the absorption of carbon dioxide in ammonia water,and investigates the influence of the particle size of the lead paste,the amount of lead paste and the operating parameters of the process after adding the lead paste on the CO₂ removal efficiency,the enhancement factor and the ammonia escape rate..The results show that the addition of lead paste particles significantly promotes the average absorption rate of CO₂absorbed by ammonia,and has a certain inhibitory effect on ammonia escape.When the particle size of the lead paste particles is 37μm and the addition amount is 0.9g/L,The enhancement factor reaches 1.167.The concentration of ammonia has the greatest impact on the rate of CO₂ absorption and ammonia escape,and both the absorption rate and ammonia escape rate increase significantly with the increase of ammonia concentration.Finally,the thesis conducted an experimental study on the use of carbonized ammonia water obtained by absorbing carbon dioxide in ammonia water for the desulfurization of lead paste,and investigated the effects of carbonization degree,reaction time,and surface renewal enhancement on the desulfurization of carbonized ammonia water lead paste,and integrated lead paste desulfurization and carbon dioxide absorption According to the requirements,a two-stage absorption process is designed.The results show that under suitable conditions,the desulfurization rate of the lead paste treated by carbonized ammonia water can reach more than 90%;the pulp concentration has a more significant influence on the desulfurization effect of the lead paste desulfurization reaction relative to the reaction time and the degree of carbonization.The greater the pulp concentration,the more the reaction The lower the conversion rate.The strengthening effect of the surface renewal device on the desulfurization of carbide ammonia was studied,and the XRD analysis of the lead paste before and after the reaction showed that almost all Pb SO₄ in the lead paste was converted to Pb CO₃,which proved the accuracy of the experiment.A secondary ammonia absorption tank for carbon dioxide absorption is designed.Under the condition of controlling the residence time of the solution in the primary and secondary pools,the clean production of carbonized ammonia lead paste pre-desulfurization can be realized,and the recycling of resources can be promoted.