75#ferro silicon Si 74.5%-80% Al 0.5%-2%max C 0.2%max P 0.04%max Mn 0.5%max Cr 0.5%max S 0.02%max 72#ferro silicon Si 72.5%-80% Al 0.5%-2%max C 0.2%max P 0.04%max Mn 0.5%max Cr 0.5%max S 0.02%max manganese silicon 6517,6514. magnesium99.95%min, 99.9%min