Bromine Extraction Process.

Te Aroha News, Volume XIV, Issue 2069, 18 January 1898, Page 2

Bromine Extraction Process.

Of the various processes now before the mining world for the treatment of refractory ores the Gold-extraction and Bromine Recovery Company, whose works are situated in Worship Street, in the City of London, claim that theirs is at once the oheapest, the quickest, and the most successful, and, we may add, the latest. It has certainly been most favorably reported upon, amongst others by Sir William Crookes, F.R.S, Professor William Ramsay, FR 8, Messrs Johnson and Sons, Mr Elwyn Waller, A,M, EM, Ph.D., Mr Peter T Austen, Ph D, Mr Parker O MoHhiney, A M, Ph D, Mr Horace F Brown, M E, Mr H P Walker, ME, and Mr F I Bicardo-Seaver, Assoc Inst CE. In this process the roasted ore is leaohed in open tanks with a solution made by adding bromine to oaiistio ores of varied composition, especially pyritio ores, may be thus treated without caeating noxious fumes, and that fine crushing is not essential. Previous to leaching the ore is made slightly aoid, and when the bromine lye oomes into oontaot with the acid bromine is set free, and attacks and dissolves the gold as bromide. The bromine liquor is then run off and the ore washed. The liquor and washings enter a tank without coming in contact with the air, any combined bromine is liberated by the addition of a mixture of bromate and chloride of sodium and an acid, and the bromine is removed by a current of air, which is blown through the heated liquid. This aircurrent passes through a tower, down whioh a stream of caustic soda is descending, and the bromine is completely absorbed, and the solution is in its initial condition, which serves for second extraction. The blown liquor is mixed with a solution of sodium, and the gold thrown down as sulphide ; from this compound the gold is easily recovered in the metallic state by roasting and fusing. Tellurides, especially, can be successfully treated by this process, whioh has one advantage which will recommend it to mine-managers and mine-owners in Western Australia, that it consumes only a minimum of water. The experiments made by Sir Wm Crookes and Professor Ramsay show that an extraction of from 99 to 95 per cent may be reckoned upon- -a result whioh it would'certainly be difficult to beat. British Australasian.