Brown fused alumina
Corundum (aluminium oxide) has been synthetically produced since the beginning of the 20th century. The synthetic corundum (normal corundum brown) is produced by reducing smelting of bauxite in an electric arc furnace at a temperature of over 2,000 °C. Unwanted accompanying substances are reduced by adding iron filings and coke. A brown corundum is produced. It is characterised by its blocky form and hardness which give it its high abrasive effect. Compared to aluminium oxide (fused alumina), brown fused alumina is tougher and not quite as brittle. This is due to its relatively high Ti02 content.