The production process of ferronickel generates an abundance of the by-product slag which has potential for use as a fine aggregate in concrete. Ferro-nickel slag (FNS) is a useful resource acquired through smelting of nickel ore at a high temperature and separated from the ferronickel. Ferronickel slag has been used in diversified ways in advanced countries including Japan and New Caledonia in addition to Korea.
It is mainly constituted of a glossy magnesium silicate structure, Forsterite ((Mg,Fe)2SiO4) and Enstatite ((Mg,Fe)SiO3). This slag contains less than 0,1% Ni. One part of Ni is on nickel metal form (60 – 70%), the other part is in substitution of Mg in the glossy magnesium silicate structure. This slag does not contain any free magnesia nor crystalline silica (quartz, tridymite, cristobalite).
Application and Uses
As an environmentally friendly raw material with excellent physical and chemical properties it can be used as a substitute for natural resources such as concrete aggregates, molding sand, abrasives, and serpentine while contributing to preserving resources and the environment.
Technical papers have shown combining ferro-nickel slag with fly ash generates stronger properties such as good sorptivity, increased strength and excellent volume of permeable voids. Durability equivalent to conventional concrete may also be achieved when FNS partially substitutes sand and fly ash partially substitutes cement. The APozA is in the process of testing supplied materials from its members to facilitate a new Australian Standard AS3582.4 for the use of Pozzolans as a supplementary cementitious material.