城市污泥尾矿陶粒的制备工艺及其性能与应用

Preparation Process of Municipal Sludge Tailing Ceramsite and Its Performance and Application

以城市污水处理厂污泥和德兴铜矿尾矿为主要原材料,经高温烧结制备陶粒,通过试验确定原材料配比和烧制工艺参数,分析陶粒的物理性能(堆积密度、表观密度、1 h吸水率、空隙率)、浸出液中重金属含量,以及陶粒对铅离子的吸附性;将陶粒以0%、20%、40%、60%、80%、100%(质量分数)的替代率替代普通混凝土中的碎石,研究混凝土的立方体抗压强度和劈裂抗拉强度变化。结果表明:按照m(污泥)∶m(尾矿)∶m(黏土)=2∶3∶1将原材料混合造粒,烧制工艺为(105±5)℃干燥3 h,400℃预热15 min,1000℃烧结12 min,制得陶粒的堆积密度为528 kg/m^(3),表观密度为1004 kg/m^(3),1 h吸水率为7.64%,空隙率为47.37%;陶粒浸出液中重金属含量均低于国家标准的限值;烧结温度为960℃的陶粒在30℃恒温水浴锅加热条件下对铅离子的吸附率达到93.57%;掺入陶粒之后,随着陶粒替代率的升高,陶粒混凝土立方体抗压强度和劈裂抗拉强度表现为先增大后减小的变化趋势,当陶粒替代率为60%时,标准养护28 d的立方体试块抗压强度达到最大(35.38 MPa),当陶粒替代率为40%时,劈裂抗拉强度达到最大(5.8 MPa)。

In this paper,municipal sewage treatment plant sludge and Dexing copper mine tailings were used as the main raw materials to prepare ceramsite by high temperature sintering.The ratio of raw materials and sintering process parameters were determined by experiments.The physical properties(bulk density,apparent density,1 h water absorption rate,void ratio)of ceramsite,heavy metal content in leaching solution,and the adsorption of lead ions by ceramsite were analyzed.The ceramsite was used to replace the gravel in ordinary concrete to varying degrees(0%,20%,40%,60%,80%,100%,mass fraction),and the changes of cube compressive strength and splitting tensile strength of concrete were studied.The results show that the raw materials are mixed and granulated according to m(sludge)∶m(tailings)∶m(clay)=2∶3∶1,and the sintering process is drying at(105±5)℃for 3 h,preheating at 400℃for 15 min,and sintering at 1000℃for 12 min.Then the bulk density of the prepared ceramsite is 528 kg/m^(3),the apparent density is 1004 kg/m^(3),the 1 h water absorption rate is 7.64%,and the void ratio is 47.37%.The content of heavy metals in ceramsite leaching solution is lower than the limit of national standard.The adsorption rate of lead ions by ceramsite sintered at 960℃reaches 93.57%under the condition of 30℃constant temperature water bath.After adding ceramsite,with the increase of ceramsite replacement rate,the cubic compressive strength and splitting tensile strength of ceramsite concrete increase first and then decrease.When the ceramsite replacement rate is 60%,the compressive strength of the cubic test block cured for 28 d reaches the maximum of 35.38 MPa.When the ceramsite replacement rate is 40%,the splitting tensile strength reaches the maximum of 5.8 MPa.