carbon silica briquette used in the manufacture of silicon, ferro silicon and silicon carbide

coal and coke and briquettes made from coal or coke or with admixture of quartz, household fuel briquettes

coal, coke, ores, briquettes made from the said materials, together with admixture of quartz, more particularly household fuel briquettes

carbon silicon briquette used in the manufacture of silicon and thermal silicon in the production of silicon metal