GB688206A - Improvements in and relating to the production of chlorine dioxide - Google Patents

Abstract

<PICT:0688206/III/1> In the process of preparing chlorine dioxide and chlorine by reacting an alkali metal chlorate and a suitable acid or acids, the aqueous chlorate and acid solutions are continuously fed as separate streams to a first unheated chamber and allowed to mix therein, while gaseous products are removed therefrom, the mixed liquids flow through the first chamber and pass, after a time, e.g. 1/2 min., not more than sufficient to allow the whole heat evolution to take place, into and through a second heated chamber in a time of 4-6 mins., while gaseous products are removed therefrom. Solutions of sodium chlorate and chloride from tank 1 and sulphuric acid from tank 2 are pumped by pumps 5, 6 through filters 3, 4 and pipes 12, 13 to first chamber 14, having an inclined bottom. The liquid mixture flows from chamber 14 through pipe 16, having glass packing which forms the liquid into a plurality of streams, into tower 22. The liquid flows over helical glass bodies 17, through which thermostatically controlled heated water at 120 DEG -160 DEG F flows, in an elongated path, so that the liquid from one stage is not mixed with that from a later stage. Spent liquid from tower 22 passes through float valve 18. Air from blower 19 passes from distributer 20 to the bottom of tower 22 and thence upwardly, saturated with water vapour through tower 22 and chamber 14, sweeping out chlorine dioxide at a partial pressure below 12 mm. Hg. and chlorine, to outlet 23. From outlet 23 the gases are passed with more air from distributer 20 to flowmeters 28, 29 for use. U-pipe 35 connected to water tank 34 is provided to flood the apparatus should the air pressure fail. A water injector may be placed at 23 if a solution of chlorine dioxide is required when the air circulation is dispensed with. Specifications 510,678 and 546,282 are referred to.