NOVELTY - Preparing (M1) silicon for photovoltaic use starting from metallurgical-grade silicon involves preparing mixture of silica powder, carbon black and binding agent selected from saccharose, starch, cellulose, polyvinyl alcohol, and NaSiO3; preparing pellets of mixture; subjecting pellets to first thermal treatment; heat-treated pellets to carbon reduction, so as to obtain silicon in molten state; subjecting to directional solidification the silicon in molten state with directional solidification furnace, so as to obtain silicon for photovoltaic use.    USE - For preparing silicon for photovoltaic use starting from metallurgical-grade silicon (claimed).    ADVANTAGE - The method is highly reliable, relatively easy, competitive costs; allows reducing the energy consumption of the production of silicon for photovoltaic use.    DETAILED DESCRIPTION - Preparing (M1) silicon for photovoltaic use starting from metallurgical-grade silicon involves selecting silica powder containing (ppm by weight) boron (B) ( less than or equal to 0.1), phosphorus (P) ( less than or equal to 0.1) and metallic impurities not exceeding 30; carbon black having (ppm by weight) B ( less than or equal to 0.1), P ( less than or equal to 0.1) and metallic impurities not exceeding 30; and binding agent selected from saccharose, starch, cellulose, polyvinyl alcohol, and NaSiO3; preparing mixture of the silica powder, carbon black and binding agent; preparing pellets of the mixture; subjecting the pellets to first thermal treatment; subjecting the heat-treated pellets to carbon reduction, so as to obtain silicon in the molten state; subjecting the silicon in the molten state to first purification; subjecting to directional solidification the silicon in the molten state with directional solidification furnace, so as to obtain silicon for photovoltaic use, and where the steps are performed in devices that have internal surfaces made of silico-aluminous ceramic materials that have silica concentration of greater than or equal to 99 wt.% and are suitable to prevent silicon contamination.