摘要
Considering that copper mine tailings(CMTs)are commonly mixed with ordinary Portland cement,fly ash(FA),and kaolin to produce geopolymers,to make full use of CMTs,the properties of geopolymers manufactured under different material mass ratios and curing methods(standard curing,water bath curing,and 60℃curing)are evaluated with significantly increased dosage of CMTs.Porosity and unconfined compressive strength tests,X-ray diffraction,field emission scanning electron microscopy,and energy dispersive spectroscopy are used to determine the physical and mechanical properties,microstructure,and mineral composition of geopolymers.Finally,costs and CO 2 emissions of specimens with different material mass ratios during the preparation processes are compared.The results show that during the geopolymerization of low-calcium materials,various geopolymer gels,including calcium silicate,calcium silicoaluminate,and mainly sodium silicoaluminate gels,coexist.The solid waste,cost,and carbon dioxide emission reductions can reach 100%,166.3 yuan/t,and 73.3 kg/t,respectively.Under a curing condition of 60℃,the sample with a CMTs mass fraction of 70%and an FA mass fraction of 30%meets the requirements of porosity,compressive strength.The resource utilization of CMT and FA is realized in a more economical way.
考虑到铜尾矿(CMTs)通常与普通硅酸盐水泥、粉煤灰(FA)和高岭土混合制成地聚合物,为了充分利用CMTs,在显著增加CMTs用量的情况下,对不同材料质量配比和养护方式(标准养护、水浴养护和60℃养护)下制备的地聚合物的性能进行了评价.采用孔隙率和无侧限抗压强度测试、X射线衍射、场发射扫描电镜和能量色散光谱来确定地聚合物的物理力学性能、微观结构和矿物成分.此外,比较了不同材料质量配比的试样在制备过程中的成本和二氧化碳排放量.结果表明,在低钙材料地聚合过程中,多种地聚合物凝胶共存,包括硅酸钙、硅铝酸钙,主要是硅铝酸钠凝胶.固废消减、成本、二氧化碳排放量分别可达到100%、166.3元/t、73.3 kg/t.在60℃的养护条件下,含有质量分数30%FA和70%CMTs的试样可以满足砖孔隙率和抗压强度的要求,并且以更经济减碳的方式实现了铜尾矿和粉煤灰的资源化利用.
基金
The National Natural Science Foundation of China(No.41877240)
Scientific Research Foundation of Graduate School of Southeast University(No.YBPY1930).
