总溶解固体(TDS)对白泥脱硫浆液氧化影响实验

摘要

为改善白泥湿法烟气脱硫工艺,研究白泥中总溶解固体(TDS)对白泥脱硫浆液氧化的影响,采用电感耦合等离子体质谱(ICP-MS)对浆液进行成分测定,研究浆液主要成分对浆液中亚硫酸钙氧化的影响,阐述了TDS对浆液氧化的影响机理,通过扫描电子显微镜(SEM)对实验产物和现场石膏样品进行分析.结果表明,高TDS对白泥脱硫浆液中亚硫酸钙氧化有明显的抑制作用,SEM结果表明,产物中生成簇状晶体,造成脱水困难.白泥脱硫石膏浆液中的可溶性盐,粒径在50～100μm,结晶效果较好,TDS抑制了白泥脱硫浆液的氧化,但是会提高溶液的过饱和度,使石膏晶体结晶良好.高TDS下Mn2+的催化作用已不再明显.白泥脱硫副产品石膏脱水困难的原因之一是浆液中CaSO3浓度过高,白泥应用于湿法烟气脱硫时应控制TDS,可保证白泥脱硫系统的正常运行,而不是只关注Cl-.%To improve white mud wet flue gas desulfurization technology, the influence of total dissolved solids (TDS) on desulfurization slurry oxidation was researched. The components of white mud slurry were measured by Inductively Coupled Plasma Mass Spectrometry(ICP-MS)and the experimental study on the effects of the main components in the slurry on sulfite calcium oxidation was carried out. The slurry oxidation mechanism of TDS was expounded and the experimental products and gypsum sample were analyzed by SEM. Results have confirmed the inhibition of TDS to calcium sulfate oxidation in white mud desulfurization slurry. The clusters of crystals were generated in experimental products,leading to dehydration difficulties. The soluble salt in the white mud slurry of plaster desulfurization gypsum is 50-100μm, with perfect crystallization effect. TDS inhibits the oxidation of the white mud desulfurization slurry, but will improve the supersaturation of the solution and hence enable the gypsum crystal. The catalysis of Mn2+ was on longer effective with high TDS. The excessive content of calcium sulfite in slurry causes difficultities to some extent for the dehydration of white mud desulfurization by-products. Besides the concern on Cl-, TDS should also be controlled in white mud desulfurization to gurantee the normal operation of the white mud desulfurization system.