Ferric Oxide Causticising Process.
The principle of this process is the expulsion of the carbonic acid from sodium carbonate by ferric oxide at high temperatures; this oxide playing the part of a weak acid, entering into a loose combination with the soda, which is overcome by water in the subsequent lixiviation process, the ferric oxide being regenerated and a solution of caustic soda obtained.
The ferric oxide is therefore continuously available. The main features of the process, disregarding the question of commercial economy, are (1) that it leaves no by-products to be disposed of, (2) that it enables the manufacturer to produce directly, without evaporation, a highly concentrated caustic lye.
This process has been worked out under the auspices of Messrs. Brunner, Mond, & Co., and there is every reason to expect an extensive application of so simple a method.