Preparation of a lightweight calcium silicate board using chlorine-containing Ti-extraction blast furnace slag and diatomite

Abstract

Chlorine-containing Ti-extraction blast furnace slag (TEBFS) is a solid waste produced during titanium removal from high-titanium blast furnace slag. Large amounts of TEBFS affect the local environment and severely limit further process development. A lightweight calcium silicate board was successfully prepared via hydrothermal synthesis. When the mass ratio of TEBFS: Portland cement: diatomite: calcium hydroxide: quartz was 46∶15∶17∶13.9∶8.1, the bulk density, bending strength, and thermal conductivity of the sample were 1.23 g/cm³, 8.2 MPa, and 0.299 W/(m·K), respectively. The overall sample performance met the D1.3 category requirements in the national standard. After being immersed in water with stirring at 30 °C for 60 min, the sample exhibited a curing chlorine efficiency of 40.6%. Mechanical grinding increased slag activity and sample performance. Grinding for 3 min, the activity index of the slag was 72.74%, and the bending strength of the sample increased to 8.7 MPa. Increasing the pozzolanic activity of the slag and reducing the amount of aggregate produced between particles had a positive effect on optimizing sample performance. This paper provides a feasible method for the diversification and clean utilization of TEBFS.

Graphical Abstract