South africa chrome ore lumpy is a highly fireproof sharpener for moulds and cores. Originally from South Africa. The sand is produced by crushing chrome ore and its washing in spiral concentrators, subsequent drying, dust cleaning, screening and sorting as per grain size. Chemical composition Cr2O3 46.0%min SiO2 1.0%max FeO 26.5%max CaO 0.3%max MgO 10.0%max Al2O3 15.5%max P 0.003%max S 0.003%max Cr/Fe 1.55/1 Physical composition Bulk Density 2.5-3g/cm3 Specific Gravity 4.0-4.8g/cm3 PH Value 7-9 The amount of the acid 2ML max Percent soil 0.1%max The sintered 1600 Filling Density 2.6g/cm3 melting temperature 2180°C