Hi Group
Some time ago in reply to a query re the "Cashcroft Process" ,I noted that I could not find any by that name...herewith however some information re the "Ashcroft Process".
This process was developed and patented by Edgar Arthur Ashcroft (1864-1938) an electrical engineer employed in Broken Hill NSW to install and supervise the electic lighting plant at the BHP Co's mine.
During his employment he observed the refractory nature of the sulphide ores and the large dumps that were of necessity discarded.
Ashcroft resigned from BHP in 1894 and devoted his time and finaces to researching the problem.
The following year, following erection of a pilot plant, he was able to interest financiers and the "Sulphide Corporation (Ashcroft's Process) Limited" was formed with a capital of more than one million pounds. A similar company was floated in the USA (I have no further knowledge of this)
The Corporation acquired the Central Mine at Broken Hill and in 1896, erected a large works at Cockle Creek near Newcastle NSW (close to coal supplies) with Ashcroft himself as Manager.
Commercial smelting commenced early the following year but proved unsucessful and after many modifications and great expenditure, within two years the plants had been converted to a conventional lead/zinc smelter.
Ashcroft was called upon to asked to resign and rerturned to Britain where he practiced as a consultant metallurgist.
The "Sulphide Works" works (not far from where I live) has successfully continued to operate as a major custom smelter it is still in production, (handling ore from Cobar) at the present time owned by Pasminco.
The Ashcroft process itself is most complex involving roasting - leaching - evaporation - filtration then electrolytic seperation ...and necessitating very accurate temperature and solution density controls....perhaps why the pilot plant proved more of a success than the commercial operation.
Regards
John
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