碱激发赤泥-粉煤灰-电石渣复合材料性能研究

Properties of Alkali-Activated Red Mud-Fly Ash-Carbide Slag Composites

采用(NaOH+Na_(2)SiO_(3))溶液、电石渣和粉煤灰来稳定赤泥,制备了碱激发赤泥-粉煤灰-电石渣复合材料.通过力学和微观性能测试,分析了复合材料的强度形成和发展机理,并通过重金属浸出试验评价了复合材料的安全性.结果表明:复合材料的强度随着赤泥掺量的降低和养护龄期的延长而提高,掺40%赤泥的复合材料在28 d龄期时的抗压强度最高可达20.1 MPa,致密的水化硅酸钙(C-S-H)和水化铝酸钙(C-A-H)的形成及赤泥颗粒的物理结合是复合材料强度增长的主要原因;赤泥中的重金属在养护28 d后形成了化合物而被固化在复合材料中,在浸泡28 d后的浸出液中未检测到重金属,证明使用强碱激发剂、电石渣和粉煤灰稳定赤泥是安全可行的.

Red mud was stabilized by using(NaOH+Na_(2)SiO_(3))solution,carbide slag and fly ash.Alkali-activated red mud-fly ash-carbide slag composite was prepared.The strength formation and development mechanism of the composite were analyzed by mechanical and microscopic property tests.The safety of the composite was evaluated by heavy metals leaching test.The results show that the strength of the composite increases with the decrease of red mud content and the increase of curing age.The composite containing 40%red mud reaches a maximum compression strength value of 20.1 MPa at the curing age of 28 d.The formation of dense calcium silicate hydrate(C-S-H)and calcium aluminate hydrate(C-A-H),and the physical combination of red mud particles are the main reasons for the increase in strength.The heavy metals in red mud formed compounds and are solidified in the composite after curing for 28 d.No heavy metals are detected in the leachate after immersion for 28 d,which proved the safety of stabilizing red mud with strong alkali activator,carbide slag and fly ash.