Dowa Mining Company

Dowa A flue-gas desulfurization process in which the sulfur dioxide is absorbed in a basic aluminum sulfate solution. The product solution is oxidized with air and reacted with limestone to produce gypsum. Developed by the Dowa Mining Company, Japan, in the early 1980s. In 1986 it was in use in nine plants in Japan and the United States. 

The Dowa Mining Company (K9) in Kosaka, Japan has developed a hydrometallurgical process shown in Fig. 15 to treat 2400 metric tons/ month of copper-zinc sulfide flotation concentrates. The microscopically fine mixture of copper and zinc sulfides was separated from lead sulfide and barite by flotation. The flotation concentrate analyzed 8.7% Cu,... 

Fig. 15. Flowsheet of the Kosaka hydrometalluigical plant, the Dowa Mining Company. Kurushima and Tsunoda (K9).

The process was developed by the Dowa Mining Company of Japan in the eariy 1980s and, by 1983, ten commercial systems were operating on a variety of smelters, sulfuric acid plants, and one oil-fired boiler (Nolan and Seaward, 1983). The process was dononstrated in the United States by UOP at TVA s Shawnee Steam Plant (Hollinden et al., 1983A). 

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