添加玻璃粉对掺混电镀污泥砖物理力学性能及浸出毒性的影响

Effects of glass powder on physical and mechanical properties and leaching toxicity of brick incorporating electroplating sludge

本文考察加入玻璃粉对掺有电镀污泥烧结砖物理力学性能及重金属浸出效果的提升效果.按照10%、20%、30%的质量比分别加入100目、300目、600目、800目的玻璃粉,烧成温度为950℃,测试了污泥砖的烧失量、显气孔率、吸水率、体积密度及抗压强度,并考察了掺加不同粒径玻璃粉对重金属浸出毒性的影响.研究表明,当掺加30%质量分数的300目玻璃粉时,砖体的各项性能最好,线性收缩率−7.55%、显气孔率10.07%、吸水率7.72%、体积密度2.01 g·cm^(−3);比表面积和平均孔径达到0.46 m2·g^(−1)和3060 nm.对砖体进行39 d的浸出毒性试验,浸出液中Cu^(2+)、Zn^(^(2+))、总Cr、Ni^(2+)的最大浓度分别为0.44、0.93、0.14、0.19 mg·L^(−1),远低于国家标准.研究还表明,除了熔融玻璃相与烧结砖的粘结外,砖体内部生成的尖晶石结构也对Cu、Zn、Ni、Cr的固定化起到重要作用.

The purpose of this study is to examine the improvement in the physical-mechanical properties of fired bricks containing electroplating sludge and the leaching performance of heavy metals.Three mass fractions(10%,20%and 30%)of waste glass powder with different particle sizes(100,300,600 and 800 meshes)were introduced in the production of the bricks,and these bricks were fired at 950℃.Mass loss of ignition,apparent porosity,water absorption,bulk density and compressive strength of fired bricks containing electroplating sludge were tested,and the influences of particle size of glass powder on the leaching toxicity of heavy metal were also evaluated.The results showed that the physical-mechanical properties of the bricks were relatively better when 30%of glass powder with particle size of 300 meshes was added.Physical properties,including linear shrinkage,apparent porosity,water absorption and bulk density,were−7.55%,10.07%,7.72%and 2.01 g·cm^(−3) respectively at this condition.Meanwhile,specific surface area and average pore diameter of fired bricks were 0.46 m2·g^(−1) and 3060 nm.The maximum concentrations of Cu^(2+),Zn^(2+),total Cr and Ni^(2+)in the leaching solution were 0.44,0.93,0.14 and 0.19 mg·L^(−1) when the leaching time was prolonged to 39 days.These concentrations of heavy metals in leaching solutions were far lower than that required in the national standard.The bonding between the molten glass and bricks played an important role in reducing the leachabilities of heavy metals.Additionally,the formation of spinel at high temperature also was an important factor for improving the immobilization of Cu,Zn,Ni and Cr.