METHOD FOR MAKING PHOSPHINE CONTAINING EXHAUST GAS HARMLESS

摘要

PURPOSE:To provide a method for making phosphine containing exhaust gas harmless with high reliability and safety with which a treatment operation to make innoxious is easy to perform. CONSTITUTION:Phosphine containing exhaust gas is brought into contact with a Fe (III)-EDTA containing liq. absorbent by a vapor-liquid contact mechanism 2 and treated. By performing the oxidation of a formed Fe (II)-EDTA, the reaction with a calcium compound at <=pH 10 and the solid-liquid separation in this order or in reverse order, the treated liq. absorbent is regenerated and a part or all of the regenerated liquid is returned by a regenerated liquid returning mechanism 6 to reuse it as a liquid absorbent.