 Medium particle size is 2-6.5 mm and fine particle size is 1-2 mm.Components include silicon dioxide SiO2 42.7%, calcium oxide CaO 0.98%, magnesium oxide MgO 2.5%, manganese oxide MnO 0.15%, iron oxide Fe2O3 8.4% and aluminium oxide Al2O3 25.1%.A pH of 6.9 and conductivity of 0.052 ms/cm are used.