A process for producing carbon from
carbon dioxide, in particular from
carbon dioxide obtained from
biomass, comprising the steps of: a) reacting
zinc oxide with
sodium hydroxide to form a solution of
sodium tetrahydroxide
zincate, in particular by dissolving
zinc oxide in
sodium hydroxide; b) using the solution from step a) to produce metallic
zinc by an alkaline galvanic process in which sodium tetrahydroxide
zincate is converted into
sodium hydroxide and metallic zinc, preferably using
sodium hydroxide obtained therefrom in step a); c) reducing the
carbon dioxide, in particular from carbon dioxide obtained from
biomass, to
carbon monoxide with metallic zinc from step b) as a
reducing agent, preferably using zinc
oxide obtained therefrom in step a), in particular without treatment;d) reducing the
carbon monoxide obtained in step c) and, if appropriate, the
residual carbon dioxide present after step c) with metallic zinc from step b), preferably using an iron-containing catalyst, to obtain a mixture of
solid carbon and zinc oxide and, if appropriate, the iron-containing catalyst; e) dissolving the zinc oxide in the mixture from step d) by adding
sodium hydroxide to form a dispersion comprising sodium tetrahydroxide
zincate,
solid carbon; f) separating the
solid carbon and, if appropriate, the iron-containing catalyst from the dispersion from step e);