Mechanism of Calcium Chlorate Formation in Wastewaters of Gas Purification during Chlorinated Gases Processing by Lime Milk

Abstract

There were presented results of investigation related to industrial wastewaters of enterprise, manufacturing process of which is accompanied by formation of chlorinated exhaust gases. Processing of exhaust gases is performed by means of lime milk’s spraying under two-stages gas purification. Industrial effluents’ analysis showed that average contain of calcium chlorate was 2 g/dm3. There was not determined calcium hypochlorite. There were determined the sources of calcium chlorate’s intake at enterprise’s wastewaters, that were gas purifying plants. During the process of exhaust gases processing by lime milk are generating oxygen containing chlorine compounds – calcium hypochlorite and calcium chlorate. Analysis of received data showed that the higher content of chlorine in purified gas, the higher content of chlorate-ion in spent milk. For reduction of calcium chlorate’s discharge the is the most adaptable with regard to availability to roll-out technology of catalytic processing, wherein calcium hypochlorite generating during the process of spraying is continuously dissipated with oxygen evolution, but not with generation of calcium chlorate. As catalyst is used mix of nickel, iron and copper salts/ One from ways that allows eliminate the problem of generation of oxygen containing chlorine compounds in spraying suspension, is substitution of lime milk for aqueous suspension of brucite – Mg(OH)2. There was established that during the processing of exhaust gases by brucite suspension is not generating oxygen containing compounds.