Verfahren zur Entfernung von Schadstoffen aus Abgasen.

Abstract

DE 3342816 A UPAB: 19930925 In a first stage, (I) are oxidised by spontaneous reaction with bromic or iodic acid or solns. or bromate or iodate salts or aq. or organic solns. of Br2 or I2 and converted completely to water-soluble acids. In a second stage, the Br2 or I2 formed in the first stage is converted to bromide and bromate or iodide and iodate and dissolved and H halides and pseudohalides are neutralised completely from the process waste gases, using a basic soln.. Pref. waste gas contains gp. V element hydrides, esp. triorganophosphanes. The HCl in the gas is neutralised in the second stage, pref. with a hydroxide soln. Several first stages are used, connected independently to process plants, and operate with a common second stage. The gases leaving the second stage are passed through carbon filters. USE/ADVANTAGE - Useful in conjuction with chemical processes, pref. those used in semiconductor mfr. (e.g. the CVD process). The gas can be freed almost completely from various harmful gases at room temp.. 0/