Ebara Manufacturing Co., Ltd.

Japan Atomic Energy Research Institute

Shoji Hashimoto

Sueo Machi

Keita Kawamura

Waichiro Kawakami

Shingi Aoki

Masao Taniguchi

Removal of gaseous pollutants such as nitrogen oxides and sulfur dioxide from effluent gases can be carried out advantageously from an industrial viewpoint by effecting irradiation of said gases under specifically selected conditions. High dose rate electron beam irradiation at a dose rate in the region of 10.sup.5 rad/sec or higher is, unexpectedly, remarkably effective and efficient for said purpose. Irradiation under increased pressure is also preferable. Wash of gases after irradiation or effecting irradiation in the presence of water vapor is effective especially for the removal of nitrogen oxides. Further, by carrying out the process in two-steps in which nitrogen oxides are removed from such gases almost completely by irradiation with the minimum dose of electron beams before sulfur dioxide is removed from the thus treated gases by conventional desulfurization means, the process can be carried out very economically. Thus, it has become industrially feasible to treat the effluent gases with irradiation, for the removal of nitrogen oxides and sulfur dioxide before releasing them into the atmosphere.

Process for removing nitrogen oxides and sulfur dioxide from effluent

Effluent gas containing SO.sub.2 and/or nitrogen oxides of various forms (referred to as NO.sub.x) are irradiated with an ionizing radiation to form aerosol. The aerosol is collected by a collecting means to form a collected material containing sulfur dioxide and nitrogen oxides. Effective components are recovered from the collected material by subjecting it either to steam-roasting with or without addition of ore of low grade, solid waste generated from smelting processes, copper-containing pyrite cinders or an alkali earth metal compound to the collected material, or to thermal decomposition.

Process for utilizing collected material removed from effluent gas

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Takasaki, Japan

Shoji Hashimoto