Watson, Cole, Grindle & Watson
Method of treating the slag from a copper converter
 A method of treating the slag from a copper converter comprises introducing the molten slag from a copper converter into a furnace having tuyeres through which air can be blown into the molten slag, blowing into the slag through the tuyeres at least 6% by weight of pulverized coal with air or oxygen-enriched air having an oxygen content of 21 to 40% by volume to separate molten metallic copper from the slag, the amount of the air having a ratio of 0.3 to 0.7 to theoretical combustion of the coal, adding a source of sulfur to the separated copper to form a molten matte, maintaining the matte at a reduced pressure not exceeding 0.6 mm Hg for at least five minutes in a vacuum refining apparatus to remove impurities from the matte by volatilization, and treating the refined matte in a copper converter used for the treatment of a matte produced by a smelting furnace. 
Sumitomo Metal Mining Company Limited
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inventional inventional inventional inventional
Takayoshi Seiichi Yoshiaka
Kimura Tsuyuguchi Mori