Research On Alkali Activated Cementitious Material Of Iron Tailings And Steel-making Slag

The preparation of alkali activated cementitious materials(AACMs)has become a hot spot of resource utilization of iron tailings in recent years.However,due to its complex mineral composition and high crystallinity,the components of Si and Al in iron tailings are difficult to form AACMs.Therefore,the alkali solution activation method is proposed to use high concentration alkali solutions dissolving a kind of high silicon iron tailings(HIT)and the low ones(LIT).The dissolved components,steel slag and alkali activator are combined in a certain proportion to prepare AACMs.The effects of alkali liquor type,concentration and temperature on the dissolution characteristics of iron tailings and the strength of AACMs were studied.The research contents are as follow:1)The iron tailings were soaked in 1 M,5 M,10 M and saturated Na OH/KOH solutions at 50℃.The dissolution of Si and Al in the two kinds of iron tailings increased with the add of concentration.The dissolution of Si and Al in the LIT and the dissolution rates of Al in the HIT increased significantly when the concentration above 10 M;2)The iron tailings were soaked in 10 M Na OH/KOH solution at 25℃,50℃,80℃,110℃ and 150℃.The dissolution rates of Si and Al in the two kinds of iron tailings increased with the add of temperature,and in the LIT increased significantly when the temperature above 80℃ and in the HIT increased above 110℃;3)Quartz,albite and augite in LIT and quartz and feldspar in HIT were largely dissolved with the add of concentration and temperature;Calcite from LIT was transformed into portlandite in high alkali concentration solution;Hematite was also partially dissolved under high temperature;4)The effects of steel slag content and iron tailings activation on the mechanical properties of AACMs were investigated.When the content of steel slag is 50%,the mechanical properties are better.The 28 d compressive strength of AACMs prepared by activation of two kinds of iron tailings can reach 19.44 MPa(LIT)and 27.56 MPa(HIT).Figure 24;Table 14;Reference 73.