机械活化和不锈钢渣掺量对矿渣胶凝材料性能的影响

为了促进不锈钢厂废渣的资源化利用,以红土镍矿酸性高炉渣和不锈钢渣为主要原料制备胶凝材料,研究机械活化和不锈钢渣质量掺量对矿渣胶凝材料性能的影响,并利用XRD、SEM对胶凝材料的水化产物及微观结构进行分析。结果表明,机械活化主要通过改变原料的比表面积和颗粒级配来影响胶凝材料性能,且矿渣中细颗粒占比是影响其胶凝活性的关键因素,适宜的球磨时间为45 min,此时矿渣比表面积达到524.66 m²/kg。不锈钢渣与酸性矿渣之间存在协同作用,当不锈钢渣质量掺量为20%时,胶砂试块3 d、7 d、28 d抗压强度分别为17.8 MPa、24.3 MPa 和34.8 MPa,抗折强度分别为4.5 MPa、6.2 MPa和6.8 MPa,达到P·S 32.5R矿渣硅酸盐水泥强度标准。不锈钢渣的掺入在水化早期和后期都促进钙矾石及C-S-H凝胶的生成,对胶砂试块各龄期强度都有促进作用,而未水化的钢渣细颗粒也起着微集料填充作用,有利于胶凝材料早期强度的提高。

Effects of Mechanical Activation and Stainless Steel Slag Content on Properties of Slag Cementitious Materials

In order to promote the resource utilization of waste slag from stainless steel factory,the cementification materials were prepared with laterite nickel mine acid furnace slag and stainless steel slag as the main raw materials.The effects of mechanical activation and the mass addition amount of stainless steel slag on the properties of cementing materials were studied.The hydration products and microstructure of cementing materials were analyzed by XRD and SEM.The results show that mechanical activation is mainly through the changes of specific surface area and particle size distribution of raw materials to affect the properties of cementing materials,and the proportion of fine particles in blast furnace slag is the crucial factor affecting the cementing activity,the optimal ball milling time is 45 min,and the specific surface area of blast furnace slag is 524.66 m²/kg.There is a synergistic action between stainless steel slag and acidic slag.When the mass content of stainless steel slag is 20%,with curing ages of 3 d,7 d and 28 d,the compressive strength of mortar test block is 17.8 MPa,24.3 MPa and 34.8 MPa,and the flexural strength is 4.5 MPa,6.2 MPa and 6.8 MPa,respectively,which reaches the requirement of P·S 32.5 R slag Portland cement strength standard.The addition of stainless steel slag facilitates the formation of ettringite and C-S-H gel at the early and late hydration stages,which increases the strength of mortar test block at various ages.The fine particles of steel slag without hydration also play a micro-aggregate filling role,which is conducive to the improvement of the early strength of cementing materials.