| Waste lead-acid battery contains a lot of sulfuric acid and lead sulfate,which will inevitably cause sulfuric acid mist and SO2 pollution in the regeneration process.This paper systematically studies the new technology of sulfur pollution,control and sulfur resource utilization in various production links of the lead regeneration industry,providing reference for the industry.Taking 150000 t/a waste lead battery storage and crushing and sorting system as an example,the ventilation capacity is 36000Nm3/hh,and the acid mist content is30-60mg/Nm3.Using 1.0 mol/L sodium hydroxide solution as the absorption solution,the spray circulation amount is 30m3/h,the average concentration of sulfuric acid mist discharge a t the storage point of waste battery is reduced to 0.54mg/m3;the spray circulation amount is 30m3/h,and the average concentration of sulfuric acid mist discharge at the crushing and separation link is reduced to1.22mg/m3;the absorption efficiency of acid mist is up to 98%,and the total sulfuric acid discharge in the waste gas can be reduced by 25.29t/a.It is an effective method to control the sulfur dioxide pollution in flue gas of the regenerated lead enterprise to pre desulfurize the waste lead paste and remelt the desulfurized lead paste.Using sodium carbonate and ammonium bicarbonate as desulfurizer,the sulfur content of desulfurized lead paste can be reduced to 0.5%of the industrial demand.When sodium carbonate is used as desulfurizer,the reaction conditions are as follows:stirring speed of 40 rpm,liquid-solid ratio of 1.5:1,molar ratio n?Na2CO3?:n?Pb SO4?is 1.05:1,reaction time of 40 min,which can reduce the sulfur content from 5-7%to less than 0.5%.When ammonium bicarbonate is used as desulfurizer,the reaction conditions are as follows:stirring speed is 40 rpm,liquid-solid ratio is 2:1,molar ratio of n?NH4HCO3?:n?Pb SO4?of 2.1:1,reaction time is 60 min,the sulfur content of the material can be reduced from 5-7%to less than 0.5%at normal temperature.After purification crystallization drying,the purity of by-product sodium sulfate or ammonium sulfate can reach more than 99%,and meet the national standard quality of first-class products,so as to realize the utilization of sulfur resources.The method of ammonium bicarbonate desulfuration combined with lead paste desulfuration and low temperature smelting flue gas desulfuration can take into account the resource utilization of lead paste and the deep purification of flue gas sulfur dioxide.On the premise that the sulfur content of the lead paste is less than0.5%,the desulfurization rate of smelting flue gas can be kept at a high level.When the SO2 inlet concentration of flue gas is 2397-3714mg/m3,u=1.36m/s,and the liquid gas ratio is 2L/m3,the desulfurization efficiency of flue gas is more than 95%;the purity of by-product ammonium sulfate is more than 99%.Absorption and concentration of sulfur dioxide in flue gas and re catalysis for acid production is another widely used method for pollution control of sulfur dioxide in renewable lead enterprises.The technology of desulfuration and acid making of1-methyl-3-butylimidazole hydrogen sulfate(C8H16N2O4S)ionic liquid was studied.When the mass fraction of ionic liquid is 20%and the temperature is 50?,the desulfuration rate is the highest,which can reach 99.36%;the best regeneration temperature is 110?,the regeneration rate can reach 96.33%,and the purity of desorption sulfur dioxide is 99.12%-99.67%;at the same time,the 98%sulfuric acid prepared accords with the national standard Requirements for first-class domestic standard?GB/T534-2014?. |
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