Abstract: The water-granulated secondary Ni slag produced by iron increase with the smelting reduction of Jinchuan nickel smelting slag is made into cemented materials with desulfurization gypsum and carbide slag as main activator and sodium sulfate and cement clinker as auxiliary activator. Then together with milled sands at the cement-sand ratio of 1∶4, the cement materials with the mass fraction of 79% are produced so as to study the effects of activator's dosage on strength of cemented materials. The results show that when the mass fraction of the water-granulated secondary Ni slag, gypsum, calcium carbide slag, sodium sulfate and cement clinker in the cemented materials are 85%, 5%, 5%, 3% and 2% separately, the comprehensive strength and bending strength of the cement materials at 28 d reach 3.42 MPa and 1.96 MPa, which meet the strength requirements of the underground filling binder. It is observed by means of XRD and SEM that under the reaction of activator the glass phase and crystalline mass in the secondary nickel slag cementitious materials can occur the hydration reaction, and the main hydration products are ettringite and silicate (aluminate) gel containing Ca²⁺ and Mg²⁺.

Key words: Water-granulated secondary Ni slag, Activator, Cemented materials, Comprehensive strength, Bending strength