RHI fused minerals plant in South Africa. By. Published: Friday, 10 November 2006. 9 November 2006. RHI Refractories to build a new Mg-Cr and Al2O3 fusion plant in Isithebe, South Africa, in a bid to increase revenue. RHI Refractories has announced that it is to establish a 30,000 tpa magnesia chrome and alumina raw materials fusion plant in ...