Powder metallurgy | Britannica
Process. Direct reduction processes can be divided roughly into two categories: gas-based, and coal-based. In both cases, the objective of the process is to drive off the oxygen contained in various forms of iron ore (sized ore, concentrates, pellets, mill scale, furnace dust, etc.), in order to convert the ore to metallic iron, without melting it (below 1,200 °C (2,190 °F)).