摘要
高比表面积氢氧化钙可以提升其在烟气脱硫过程中的反应效率.采用工业级生石灰为原料湿法消化制备高比表面积氢氧化钙,以二甘醇(DEG)和三乙醇胺(TEA)作为复配消化助剂(DEG/TEA),考察了 DEG/TEA复配质量比、DEG/TEA复配助剂添加量、消化温度、水灰比、消化时间和生石灰活性度对氢氧化钙比表面积及粒径的影响;利用比表面积分析仪、纳米粒度仪、扫描电镜、X射线衍射仪及红外光谱仪对氢氧化钙进行表征分析.结果表明,较佳的湿法消化反应条件:DEG/TEA复配质量比1∶2、DEG/TEA复配助剂添加量7.5％(质量分数)、消化温度为70 ℃、水灰质量比为4∶1、消化时间为40 min,所制备的氢氧化钙比表面积为64.44 m2/g,总孔容积为0.265 cm3/g,平均粒径为0.800 μm,其微观形貌为纳米片状层层堆叠而成的团聚体,且具有发达的狭缝孔结构.研究发现,同样消化条件下,生石灰活性度越高,所制得的氢氧化钙比表面积越大.最后,提出了高比表面积氢氧化钙可能的形成机理.
Abstract
High specific surface area calcium hydroxide can improve its reaction efficiency in the flue gas desulfurization process.Industrial quicklime was used as raw material to prepare high specific surface area calcium hydroxide by wet diges-tion.Diethylene glycol(DEG)and triethanolamine(TEA)were used as compound digestion additives(DEG/TEA),and the effects of DEG/TEA compound mass ratio,DEG/TEA compound additive amount,digestion temperature,water-to-lime ra-tio,digestion time and quicklime activity on the specific surface area and particle size of calcium hydroxide were investi-gated.Calcium hydroxide was characterized and analyzed by specific surface area analyzer,nano particle analyzer,scanning electron microscope,X-ray diffraction,and infrared spectroscopy.The findings indicated that the optimized wet digestion re-action conditions were as follows:DEG/TEA compound mass ratio of 1∶2,DEG/TEA compound additive amount of 7.5％(mass fraction),digestion temperature of 70 ℃,water-to-lime ratio of 4∶1,digestion time of 40 min.The specific surface area of the prepared calcium hydroxide was 64.44 m2/g,the total pore volume was 0.265 cm3/g,and the average particle size was 0.800 μm.Its micro-morphology was agglomerates formed by layer-by-layer stacking of nano-flakes,with well-developed slit pore structure.The research results revealed that the higher the activity of quicklime,the greater the specific surface area of calcium hydroxide produced under the same digestion conditions.Finally,the possible formation mechanism for high specific surface area calcium hydroxide was proposed.
维普
万方数据