高钙矾石改性剂对污泥孔隙结构的影响  

Influence of pore structure change on high content of ettrigite modified sludge effect

作　　者：朱熙[1,2] 李飞[1,2] 宋永伟[1,2] 

机构地区：[1]中南财经政法大学信息与安全工程学院,武汉430073 [2]中南财经政法大学环境与健康研究中心,武汉430073

出　　处：《环境工程学报》2017年第7期4331-4336,共6页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(51308076;51178172;51509087);中南财经政法大学青年教师创新项目(31541311313)

摘　　要：污泥结构的改变有利于污泥资源化利用,采用硅酸盐改性污泥研究颇多,然而水化硅酸盐改变污泥孔隙结构的微观分析较少。用硅酸盐基高钙石改性剂S1(富硫型),S2(贫硫型)、常规硅酸盐水泥、石灰,在不同养护环境下改性脱水污泥,考虑改性剂水化生成物对污泥含水率、污泥孔隙率和孔隙结构特征的影响。结果表明,不同改性剂在污泥环境水化产物差别大,水化早期,S1可在污泥中快速大量产生完整针棒状结构钙矾石/铁钙矾石(长3μm左右),S2主要生成六面体型铝酸钙、铁铝酸钙产物(直径3μm左右),水泥早期产物钙矾石生长受到抑制、形态残缺短小(长13μm左右),石灰主要生成片状氢氧钙石(直径10μm左右)。针棒状钙矾石有利于污泥孔隙均匀分散、结构破坏。当投加20%(占污泥总量比例)S1改性污泥,在有氧条件下养护7 d,污泥孔隙率由32.64%增加至49.14%,含水率降到30%以下。研究表明高钙石改性剂可以有效改变污泥孔隙结构,利于污泥孔水分蒸发提高自然干化效率。Sludge resources can be effectively utilized by controlling the sludge structure,a process that is usu- ally realized using silicates as modifying agents. Much effort has been devoted to studying the mechanical effect and toxicity leaching of sludge solidified by silicates, whereas little attention has been paid to analyzing the sludge pore structure. In this study,the sludge was modified by four types of agents including High anorthite modifier S1 （Silicate Base,sulfur rich type）, Modified S1 agent （ S2, Silicate Base, low sulfur type）, SPortland cement, and Lime. The effects of the hydration products of these agents on the water content, porosity, and pore structure of the sludge were studied. Moreover, it was found that huge differences exists among hydration products once modi- fiers are added to the sludge. At the early stage of hydration,S1 produced complete needle-shaped ettringite or i- ron ettringite - 3 μm long. The hydration products of S2 were hexahedron-shaped calcium aluminate or calcium ferrite with diameter of - 3 μm. Ettringite,as the hydration product of cement,exhibited limited growth reflected by its incomplete,short shape （length -3 μm）. Lime had the hydration product Portlandite, with a sheet-like form and diameter around 10 μm. The needle-shaped ettringite promotes the uniform distribution of pores and structural damage in the sludge. When 20% S1 （in relation to total content of sludge） was added to modify the sludge,the porosity of the sludge increased from 32.64% to 49.14% ,while its water content dropped to 〈 30% after curing for seven days under aerobic conditions. According to the experimental results,Sl effectively changed the pore structure of the sludge to facilitate evaporation of water from the sludge pores, thus improving the effi- ciency of sludge drying under ambient conditions.

关 键 词：污泥 钙矾石 改性 孔隙结构 

分 类 号：X799.3[环境科学与工程—环境工程]