The Romance of Modern Chemistry

THE VALUE OF THE BY-PRODUCT At length, after a series of abortive attempts, success was attained. By a process patented in England in 1888, 90 per cent, of the sulphur in alkali waste is recovered, and can be sold as pure sulphur. Even in 1893, only five years after the patent was taken out, 35,000 tons of sulphur were recovered by this method in England alone. From the public point of view also, this utilisation of alkali waste is welcome, for sulphur was the constituent of the waste which was responsible for its objectionable properties. Once the sulphur is removed, as is done nowadays, the residue is innocuous and unobjectionable, so that the nose of the community is no longer offended. Not always have private profit and public interest been served together as in this utilisation of alkali waste. With the economy thus effected, the Leblanc process has entered on a new lease of life. At the same time it is interesting to note that some manufacturers who use the Leblanc process turn out no carbonate of soda at all, but caustic soda, bleaching powder, and pure sulphur. It is in respect of these secondary products that the Leblanc process has an advantage over its rival. The story of the soda industry is interesting because of its varying fortune, and because of the illustration it furnishes of the value of the by-product. Even yet it is not quite certain that the industry is at the end of its vicissitudes, for the manufacture of alkali and bleach by electrolytic methods is being rapidly developed,and bids fair to be a formidable competitor. Time only can show whether these new methods will be able to overthrow the older processes of soda manufacture. 279