Sammendrag
Bauxite residue (BR) contains typically 20 to 50% iron oxide. A full valorisation of
the BR requires that this iron is returned to the market. It is not difficult to recover
this iron as pig iron, but the market price for pig iron is too low to make this
economically viable. Iron alloys with high silicon content have higher value than pig
iron, and BR contains between 5 and 15% silicon oxide. Therefore, it is attempted
to produce iron alloys from BR with the maximum possible Si content, extracting as
much silicon as possible from the BR and increasing the value of the metal. Bauxite
residue sourced from 3 different alumina refineries and one legacy site have been
tested in both fluxed and unfluxed experiments, supported by thermodynamic
modelling. A maximum silicon-level of 17 wt% in the metal alloy has been achieved
in experiments with BR fluxed with quartz.
the BR requires that this iron is returned to the market. It is not difficult to recover
this iron as pig iron, but the market price for pig iron is too low to make this
economically viable. Iron alloys with high silicon content have higher value than pig
iron, and BR contains between 5 and 15% silicon oxide. Therefore, it is attempted
to produce iron alloys from BR with the maximum possible Si content, extracting as
much silicon as possible from the BR and increasing the value of the metal. Bauxite
residue sourced from 3 different alumina refineries and one legacy site have been
tested in both fluxed and unfluxed experiments, supported by thermodynamic
modelling. A maximum silicon-level of 17 wt% in the metal alloy has been achieved
in experiments with BR fluxed with quartz.