gold for the treatment of arthritis was due to the fact that in the early
decades of the 20 th century, arthritis was thought to have an infectious
origin while gold shows antimicrobial properties. Subsequently, the anti-
rheumatic efficacy of gold compounds was confirmed, independently of
their antibacterial action. Although there is also the gold sodium thiomalate
│ gold sodium thiomalate │sodium aurothiomalate salt (^) [ 76 ].
In the case of gold sodium thiosulphate (^) [ 77 ] it is a metal that is
commonly associated with allergic reactions and is linked to gold jewellery,
occupational exposure to gold, treatment of rheumatoid arthritis, dental
restorations and gold-plated intracoronary prostheses. Like other metals,
sodium gold thiosulphate can form soluble salts in the presence of sweat or
other biological fluids. The salts can be released or absorbed and cause an
immune reaction in certain individuals.
But within the extraction of gold from polysulphide ores using
ammoniacal solutions of sodium thiosulphate (^) [ 78 ] and the presence of
cupric ions it is a good non-toxic alternative to cyanidation. For this reason,
a comparison between cyanidation and leaching with ammoniacal
thiosulphate solutions was carried out to determine the effectiveness of
both methods. In cyanidation a gold recovery of 80. 6 % was obtained after
24 hours of agitation while in thiosulphate leaching 80. 9 % gold recovery
was achieved in one hour. The leachates obtained were subjected to five
techniques in order to extract the gold contained in these solutions. The
most successful technique was ionic flotation with a gold recovery of 84 %.
Subsequently, electrolysis of the ionic flotation concentrate (froth) was
carried out at a voltage of 1. 5 V for 3 hours, which allowed a gold recovery
of 82 %.
It is also important to mention that according to the technical
treatise "The Elements, Third Edition", written by John Emsley and
published by Clarendon Press, Oxford in (^1998) [ 79 ], the body of an