The invention concerns a method for producing a medium purity silicon comprising: preparing, by carbothermic reduction of silica in a submerged arc-furnace a silicon with low boron content; refining the liquid silicon with oxygen or chlorine; treating the refined silicon under reduced pressure from 10 to 100 Pa with neutral gas injection; segregated solidification. The invention also concerns a medium purity silicon designed to serve as raw material for making silicon of electronic or voltaic quality, and having (in weight fractions): a total of impurities ranging between 100 and 400 ppm, with the content in metallic elements ranging between 30 and 300 ppm; a boron content from 1 to 10 ppm; a phosphorus/boron ratio ranging between 0.5 and 1.5.