Hydrogen as reductant – What does that mean?
Metals exist in the earth’s crust mainly as oxides. It means that every metal atom is attached to one or more oxygen atoms. They form very strong bound, like a marriage. To break these bounds, we need a reductant to steal the oxygen atoms from the metal atoms. Normally carbon is used in combination with a lot of energy. Carbon will steel oxygen from the metal atoms and form CO2. The metal atoms are left alone – as pure metals.
The CO2 emission from this process is called direct emissions. There is also indirect emissions in connection with metal production, since it is an energy intense process. These indirect emissions will vary depending on the energy source used.
To eliminate the direct emissions, an alternative reductant is needed. In other words, we need another atom to steal the oxygen atoms from the metal. If we can get the hydrogen atoms to steal oxygen from metal atoms, we will produce H2O (water) and metals!
HARARE aim to utilise metal oxides from metal waste streams (bauxite residue from the aluminium industry and copper slag from copper production) and hydrogen to produce pure metals!
If we succeed, we will eliminate waste and produce metals without direct emissions of CO2.