Step 3. Reduction of metal oxide to metal
The batch is placed in the bell furnace when it has reached the desired temperature: around 550 °C. The internal atmosphere is flushed with nitrogen gas (N2) and thereafter evacuated. In this step, the main goal is to control the internal environment, where elimination of the oxygen gas (O2) is of great importance. Hot hydrogen gas (H2) is then introduced into the chamber and the reduction process starts.
Our only by-product, water, is formed during the reduction. The reduction process is designed to work with gravity and temperature as well as pressure changes. In addition, the process is internally circular: the incoming hydrogen is heated by the outgoing gas with minimal heat loss. Overall, it makes our process very energy efficient. Water continues to form in until all available oxygen in the material has been removed. This process is fuelled by three forces of nature, layering of hot/cold, gravity, and pressure difference, and takes approximately one hour.