Abstract: A process for producing silicon comprising reacting silica with a reducing gas comprising carbon monoxide, wherein the reducing gas does not contain elemental carbon. A reactor for producing silicon comprising a carbon combustion chamber for reacting carbon with oxygen to generate a reducing gas comprising carbon monoxide, wherein the reducing gas contains no elemental carbon; a reaction chamber for reacting the reducing gas containing no elemental carbon with silica, the reaction chamber communicating with the carbon combustion chamber; a temperature controller for controlling the temperature of the reaction chamber; a silica inlet port communicating with the reaction chamber for admitting the silica to the reaction chamber; and a silicon outlet port communicating with the reaction chamber for allowing the silicon to leave the reaction chamber.