矿渣碳化硬化过程的研究

Process of Slag Carbonization and Hardening

将矿渣压制成2×2×2 cm^3的立方体试块,分别在30℃、60℃、90℃、120℃条件下于CO_2气氛中碳化。对碳化试块的质量、抗压强度变化进行了测定。采用X射线衍射仪(XRD)、热重-差热分析仪(TG-DSC)分析了碳化过程中的物相变化。用扫描电子显微镜(SEM)观察了碳化后产物的微观形貌。结果表明,矿渣试块的抗压强度及质量变化均随碳化温度的增加而增加,且随碳化龄期的延长而增加。矿渣在90℃条件下碳化6 h的抗压强度达41.2 MPa,质量增加9.9%,在此条件下1 kg矿渣可固化储存99 g的CO_2。矿渣的碳化产物主要为CaCO_3,未生成C-S-H凝胶和Ca(OH)_2。结果表明了矿渣在固碳的同时亦能硬化形成良好力学强度的块体材料,这是"以废治废"的良好途径。

Slag was pressed into blocks with 2 × 2 × 2 cm^3 cubic shape,and then they were carbonized in CO_2 at various temperature of 30,60,90,120 ℃. Mass and compressive strength of these test blocks before and after carbonization were measured. Phases changes during slag carbonization were characterized by XRD and TG-DSC. SEM was conducted to observe the microstructure of the carbonized products. The results indicate both compressive strength and mass increased with the increase of temperature,and increased with prolonging carbonization time. After carbonization at 90 ℃ for 6 h,compressive strength of the slag test block was up to 41. 2 MPa,and mass increased by 9. 9%; It also indicates 99 g CO_2 can be absorbed by 1 kg slag. The main carbonization product of slag was CaCO_3,and no C-S-H gel or Ca（OH）_2 was formed. This research indicates slag not only absorb CO_2 but also can form bulk material with good compressive strength,which means carbonization of slag is an efficient way to utilize slag and reduce CO_2 emission.