材料期刊网

因活性低、体积稳定性差，钢渣在蒸压砖中的用量受到限制。以钢渣-尾矿-水泥蒸压体系为基础，增加旨在改善钢渣安定性的预养护阶段。同时，加入柠檬酸钠作为抑制剂，减少预养护阶段钢渣中胶凝成分的损失。结果表明，当柠檬酸钠掺量为钢渣掺量的2%时，钢渣在尾矿蒸压试块中的安全用量由未改性时的11%提高至45%，水泥用量由7%降低至4%，其抗压强度从10.6提高到30.1 MPa。借助化学结合水量、游离氧化钙质量分数及XRD分析了钢渣的水化特征，柠檬酸钠在大掺量钢渣-尾矿-水泥体系中既是钢渣改性过程中硅酸二钙和硅酸三钙水化的抑制剂，又是蒸压条件下激发钢渣的水化活性激发剂。机械磨细、湿热条件和柠檬酸钠的协同作用强化了体系的水化反应过程。

Because of low hydrate activity and poor volume stability,the use of steel slag in autoclaved brick is limited. Based on the autoclave system of steel slag-tailings-cement,the pre-curing period was used in order to improve the stabil-ity of steel slag. Meanwhile,sodium citrate was added as the retarder to reduce the loss of cementitious activity in slag. Main results indicated that when the dosage of sodium citrate was 2%(based on the mass of steel slag),the compres-sive strength of the autoclaved brick increased from 10.6 MPa(without modification)to 30.1 MPa while the amount of steel slag in brick increased from 11%to 45%and the amount of cement reduced from 7%to 4%. The hydration charac-teristics of steel slag were analyzed by measuring its chemically combined water and free-CaO and by using X-ray spec-trometer. For the autoclave process with high volume steel slag-tailings-cement,sodium citrate works as not only the re-tarder for hydration of dicalcium silicate and tricalcium silicate in the process of the steel slag modification,but also the activator in autoclave process. The hydration process was intensified by the synergistic effect of mechanical grinding,hy-grothermal treatment and sodium citrate.