Asahi Glass Company, Limited

Mitsubishi Kakoki Kaisha Ltd.

Kenichi Shimizu

Hisashi Kakuta

Shigetada Matoba

Ryuichi Hirota

Shigetado Motoba

Mitsuaki Narita

Satoshi Yamashita

Ryoichi Kanno

Selenium is recovered from combustion waste gas, especially the combustion waste gas evolved from glass melting furnaces by a process in which the waste gas is contacted with an absorbing solution containing an alkali metal sulfite or bisulfite, whereby metallic selenium and selenium compounds are absorbed, the temperature of the waste gas is decreased and the humidity of the waste gas is increased. The treated waste gas in then passed through a moist glass fiber filter which collects the remaining amounts of selenium from the waste gas. The absorbing solution is combined with the solution used to wash the glass fiber filter and the combined solutions are treated with an acid which reduces all of the selenium present in the solution to metallic selenium which precipitates from solution.

Process for the recovery of selenium from waste gas

A process is described for the removal of oxides of sulfur, dust and mist from a combustion waste gas such as the waste gas evolved from a glass melting furnace in which the waste gas is contacted with an absorbing solution containing an alkaline absorbent such as NaOH, Na.sub.2 CO.sub.3 or Na.sub.2 SO.sub.3, whereby the oxides of sulfur are absorbed and the temperature of the waste gas is decreased and the humidity of the waste gas in increased. The treated waste gas is then passed through a glass fiber filter which is maintained under moist conditions in order to efficiently remove dust and mist particles from the waste gas. Crystalline sodium sulfate hydrate is recovered from the absorbing solution contacted with the waste gas.

Process for removing oxides of sulfur, dust and mist from combustion

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Yokohama, Japan

Kenichi Shimizu