Abstract: The recycling of waste activated carbon is of great significance in environmental protection.Porous mullite ceramics were prepared by impregnating the mullite precursor with activated carbon,and adopting aluminum sulfate octahydrate,ammonia and silica micropowder as raw materials,waste activated carbon after heat treatment as the pore forming agent,and sodium polyacrylate (PASS) as the dispersant.The effects of the activated carbon addition (1.5%,3.0%,5.2% and 7.8%,by mass) and PASS addition (1%,2% and 3%,extra adding,by mass) on the physical properties,phase composition and microstructure of the porous ceramics were studied.The results show that:(1)as a pore forming agent,activated carbon promotes the formation of pores inside the sample,while the apparent porosity of the samples increases significantly with the increasing activated carbon addition;when the activated carbon addition is 7.8%,the apparent porosity of the sample is 65.7%,the cold crushing strength is 4.62 MPa,the peak pore size is around 3.5 μm,and the pore size distribution is uniform;(2) appropriate PAAS helps to improve the dispersion of activated carbon in the samples and the comprehensive performance of the porous mullite ceramics;when the PAAS addition is 2%,the apparent porosity of the sample is 71.8%,the cold compressive strength is 5.53 MPa,the peak pore size is around 3 μm,and the pore size distribution is optimized;however,excessive PAAS increases the liquid phase in the system,resulting in over sintering of mullite and a decrease in the porosity.

Key words: waste activated carbon, porous mullite ceramics, impregnating precursor, dispersant

摘要： 废弃活性炭的回收利用在环保方面具有重要意义。以十八水合硫酸铝、氨水及SiO₂微粉为原料,利用热处理后的废弃活性炭作为造孔剂,以聚丙烯酸钠(PASS)为分散剂,采用活性炭浸渍莫来石前驱体制备莫来石多孔陶瓷,研究了活性炭(添加质量分数分别为1.5%、3.0%、5.2%和7.8%)和PASS分散剂(外加质量分数分别为1%、2%和3%)对多孔陶瓷的物理性能、物相组成及显微结构的影响。结果表明:1)活性炭作为造孔剂促进了试样内部气孔的形成,并且随其加入量的增加,试样显气孔率显著提高;当活性炭加入量达到7.8%(w)时,试样的显气孔率达到65.7%,常温耐压强度为4.62 MPa,孔径峰值约为3.5 μm,孔径分布均匀。2)适量添加PAAS有助于改善活性炭在试样中的分散情况,提升多孔莫来石陶瓷的综合性能;当PAAS外加量为2%(w)时,试样的显气孔率为71.8%,常温耐压强度为5.53 MPa,孔径峰值约为3 μm,孔径分布得到优化;然而,过量添加PAAS会增加体系中的液相,导致莫来石过度烧结并使气孔率降低。

关键词: 废弃活性炭, 莫来石多孔陶瓷, 浸渍前驱体, 分散剂