The New Experiment Research Of Damped Lead Paste Desulfurization Based On The Particle Grinding Effect

Lead-acid battery recycling waste is an important part of national economy, fragmentized separation of the lead-acid battery to scrap lead paste for desulfurization process, and the low temperature melting is recognized as a clean recycling process of lead.Traditional desulfurization reaction in batch stirred tank, the effects of the hydraulic shear mixing to break the reactants lead sulfate particles surface parcel desulfurization layer. Although the reactor has the advantages of simple structure, but there is low conversion rate, the problem is not completely desulfurization, resulting in low temperature melting cannot be carried out.This paper presents a new pre-desulphurization process of the damped lead paste based on "Surface Update" model. "Surface renewal" mode is to add particles as grinding media, which grinds reaction particles in the reactor in high speed rotation and instantly damage the product of the lead carbonate layer, to achieve the surface of the reaction particles update. Thus we construct the experiment system and study the desulfurization performance of the sodium carbonate. According to the experimental results, the process can maintain the sulfur content of lead paste under 0.5% at the optimum reaction conditions:stirring rate 500r/min, temperature 50℃, the slurry concentration 30%-60%, the molar ration(Na2CO3):n(PbSO4)= 1.1:1, reaction time 40 min.In order to adapt to the large-scale industrial production,construction of desulphurization system in internal circulation grinding, slurry paste also arranged in the tank 2 grinding desulfurizer.Desulfurization device is arranged on the lower part of high speed stirring slurry as paste slurry circulating through the power source of the desulfurizer and desulfurizing device arranged spiral deflector, and the filler particles as the abrasive medium.Using (NH4)2CO3 as the sorbent, paste desulphurization experimental study on the performance of the internal circulation grinding desulfurization system.According to the experimental results, the process can maintain the sulfur content of lead paste under 0.3% at the optimum reaction conditions:stirring rate 600r/min, temperature 40℃, the slurry concentration 30%-60%, the molar ration(Na2CO3):n(PbSO4)=1.1:1, reaction time 30 min.Heavy metal impurities in the purification of the paste desulphurization by-product comprehensive utilization is of vital importance, using ammonium sulfate precipitation method to purify the desulfurization by-product ammonium sulfate solution of heavy metals.The effect of the excessive amount of ammonium bicarbonate on the purification of heavy metals was studied. The effects of temperature, pH and ammonium sulfide addition on the removal of heavy metals were studied. Under the following conditions, C (Mn+):C ((NH4)2S)=1:2.5、 25℃-3℃、 pH=8-9, reaction time 30 min, the total amount of heavy metal impurities is reduced to less than 0.94mg/L, which meets the standard of heavy metal content in the national wastewater.