Study on mechanically activated ferrous extraction tailing of nickel slag as cementitious materials: Physical and chemical properties, mechanical properties and reaction mechanism

Abstract

Mechanical activation is a solution to the problem of low reactivity of ferrous extraction tailing of nickel slag (FETNS). In this paper, FETNS was treated with different ball milling times (5 min, 10 min, 20 min). The effects of mechanical ball milling on the microstructure, mineral phase composition, and particle size distribution of FETNS were analyzed. The effects of mechanical ball milling on the properties, reaction products, and pore structure of the FETNS-OPC composite cementitious system were studied. The experimental results show that mechanical ball milling increases the fineness of FETNS and the amorphous phase content. The compressive strength of the composite cementitious system increases with the increase of ball milling time. The compressive strength of 3d, 7d, 28d, 60d, and 90d increases by 65.96%, 22.3%, 14.97%, 23.43%, and 9.12%, respectively. X-ray diffraction test and simultaneous thermal analysis show that the increase in ball milling time promotes the formation of reaction products. The hydration heat test shows that the increase in ball milling time increases the heat release rate of the early hydration reaction. N2 adsorption-desorption experiments show that the increase in ball milling time increases the number of fine pores in the slurry, reduces the number of coarse pores, and improves the compactness of the internal structure. Mechanical activation can stimulate the reactivity of FETNS, which is conducive to the application of FETNS in building materials.