Newbery–Vautin chlorination process

The Newbery-Vautin chlorination process is a method for extracting gold from its ore through the use of chlorination. This process was jointly developed by James Cosmo Newbery and Claude Vautin.

Chlorination process

A process for extracting gold from gold ores containing pyrite using chlorine gas was introduced by Karl Friedrich Plattner, around 1848.[1]

James Newberry and Claude Vautin began work on chlorination, at the United Pyrites Gold Extracting Co. in Bendigo, in 1878. They were awarded Victorian Patent No. 4484, in 1886, for their Newbery-Vautin chlorination process, which was faster than earlier chlorination processes.[2][3]

Roasted gold-bearing pyrite concentrates and water were combined in a barrel, which revolved during the extraction process. Calcium chloride and sulphuric acid were added. The barrel were then made airtight. Compressed air was used to raise the internal pressure to four atmospheres, and the barrel was set in rotation. The sulphuric acid and calcium chloride reacted to form chlorine gas. The gold contained in the concentrate reacted with the chlorine to form gold chloride, which is a salt soluble in water. Once the extraction had occurred—after around four hours—the liquid containing the gold chloride was separated from the solid residue, by vacuum filtration, and passed through a charcoal filter, where gold precipitated. The charcoal containing the gold precipitate was burnt and the ashes fused with borax to produce gold bullion.[2]

Successor processes

The Newbery-Vautin process and other processes based on chlorination were replaced by processes based on cyanidation, which used fewer reagents. Processes that are free of cyanide and emit less toxic byproducts have also been developed.[4]

References

  1. ↑ Marsden, John; House, Iain (2006). The Chemistry of Gold Extraction, Second Edition. ISBN 9780873352406. Retrieved 2 January 2013.
  2. 1 2 McQueen, Ken (October 2012). "Early Developments in Treating Pyritic and Refractory Gold Ores in Australia" (PDF). Journal of Australasian Mining History. 10: 93, 94.
  3. ↑ Birrell, Ralph W. (September 2004). "The Extraction of Gold by Amalgamation and Chlorination" (PDF). Journal of Australasian Mining History. 2: 26, 27.
  4. ↑ Liddell, K.S.; Adams, M.D.; Smith, L.A.; Muller, B. (June 2019). "Kell hydromettalurgical extraction of precious and base metals from flotation concentrates - Piloting, engineering, and implementation advances". Journal of the Southern African Institute of Mining and Metallurgy. 119 (6): 585. doi:10.17159/2411-9717/602/2019. S2CID 201080511.
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