Experimental Study On Absorption Of Sulfur Dioxide By Lead Paste Slurry

Waste lead battery recycling enterprises will produce SO2 pollution in the production process.It is one of the most urgent needs of the secondary lead industry to seek a low-cost and non-secondary pollution-free green recycling flue gas desulfurization technology suitable for the long-term development of the industry.Based on the resource characteristics of the secondary lead industry,this paper proposes the use of lead paste slurry to absorb SO₂ in flue gas,and conducts research from three aspects:mechanism research,experimental research and economic analysis.The use of lead paste slurry to absorb SO₂ flue gas can not only remove low concentration SO₂ in flue gas to achieve pollution reduction,but also save the purchase cost of absorbent,and no problem of by-product treatment.The flue gas desulfurization technology can be applied in the industry well,and has theoretical research significance and practical application value.Firstly,the physicochemical properties of the experimental raw material lead paste were analyzed by particle size analyzer,X-ray diffractometer and chemical analysis method.The analysis results show that 83.97%of the lead paste particles have a particle size of less than 60 um,and the main components and contents are:PbSO4?50%⁵6%?,PbO2?30%³5%?,PbO?10%¹5%?and Pb?3%⁴%?.It is indicated that the lead paste particles have small particle size,good dispersion,and high content of desulfurization potential components,which is suitable for use as a desulfurizer.Secondly,the chemical reaction mechanism of SO₂ absorption in lead paste slurry was analyzed from the thermodynamic point of view by means of the E-pH diagram of SO2-Pb-H2O system.The analysis results show that the dominant desulfurization active component in lead paste is PbO₂,and the dominant reaction in the system is PbO₂+SO₂=PbSO₄,the?E of the reaction is 1.575,and the chemical equilibrium constant K value is 3.392×10⁵⁰.The reaction driving force is large and has development potential.Then,the macroscopic kinetic analysis of the reaction process by means of the double membrane model,the total resistance of the SO₂ absorption of the lead paste slurry is mainly affected by the resistance of the SO₂ dissolution and diffusion process and the resistance of the interface chemical reaction.The dissolved desulfurization product PbSO₄ is in the solid phase and liquid.The effect of the diffusion resistance in the phase body on the reaction rate is negligible.Next,the lead slurry absorption SO2 laboratory test and amplification experiment were performed.The desulfurization efficiency of the lead paste increases continuously with the increase of liquid-gas ratio,and the liquid-gas ratio is the biggest influencing factor of the absorption of SO2 by the lead paste slurry.The desulfurization efficiency of the lead paste increases first and then decreases with the increase of the liquid-solid ratio of the slurry,and the optimum liquid-solid ratio is 8:1L/kg.The desulfurization efficiency of the lead paste increases slightly with the increase of the reaction temperature,and the post-reduction trend is optimal at 40?.The desulfurization efficiency of the lead paste increases slowly with the increase of the initial pH value of the slurry.The desulfurization efficiency of the lead paste continuously decreases with the increase of the SO2 concentration at the inlet.Finally,combined with the amplification experimental data,the economic analysis of the lead paste slurry flue gas desulfurization process is carried out.Compared with the lime-gypsum flue gas desulfurization process,the initial investment of the lead paste slurry flue gas desulfurization process can save 34.89%,and the annual operating cost can save 75.65%.The lead paste slurry flue gas desulfurization process has better economic benefits and can be well promoted.