Wet Process for Extracting Gold from Gold Ores or Gold Ore Waste.
Year: 1897

page_text: Date of Application (in United Kingdom), 11th Aug., 1897
Complete Specification Left, 11th Aug., 1897-Accepted, 11th Dec.,
189
Wet Process for Extracting Gold from Gold Ores or Gold Ore Waste.
I, JOHN LANDIN of 40 Drottningsgatan, Stockholm Sweden Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement.
The wet processes heretofore used for extracting gold from gold ore have chiefly
been based upon the solubility of the gold in materials which contain or develop
free chlorine or bromine, such for instance as nitro-muriatic acid, chloride of
lime, or muriatic or sulphuric acid or in cyanide compounds as for instance
cyanide of potassium.
The object of this present invention is to extract the gold by means of solutions
which while containing or developing chlorine or bromine also contain chlorine
or bromine compounds of such metals which with the chlorine or bromine are able
to form higher chlorine or bromine compounds, such as superchlorides which like
a kind of carriers cause the dissolving action of the chlorine upon the gold. Such
suitable metals are for instance lead and manganese, but even the higher chlorine
compounds of nickel or cobalt as well as iron and other metals have a favourable
influence upon the extraction of the gold.
Solvents of this kind, containing also higher chlorine or bromine compounds,
extract the gold more easily than the solutions containing only chlorine or
bromine. The gold is thus very easily extracted by means of a chloride of lime
solution acidulated with muriatic or sulphuric acid to which is added lead
chloride, Pb Cl₂, which is thereby transformed into superchloride, Pb Cl; the
case is analogous with regard to an addition of chloride of manganese, Mn Cl₂,
which by free chlorine is transformed into superchloride of manganese, Mn C₁₁,
and so also with the chlorine compounds of other metals which by free chlorine
are transformed into higher chlorine compounds.
The aforesaid favourable action of the higher chlorine or bromine compounds is
explained by that the chlorine or bromine thereby always acts as it were in a
nascent state, as the higher chlorine or bromine metals easily give off a part
of their chlorine or bromine to the gold, which is then extracted in the form of
chloride of bromine of gold, whereupon the lower chlorine or bromine compounds
thus formed are transformed in higher chlorine or bromine compounds by a new
accession of chlorine or bromine.

page_text: In order to describe the new process more fully I shall select chloride of lead as
an example of a chlorine or bromine metal acting in this manner, and as an
example of a chlorine (or bromine) developing solution a chloride of lime solution
acidulated by muriatic or sulphuric acid as an example of a chlorine or bromine
developing solution. Through treatment of the chloride of lime with water
a solution is first obtained the strength of which is chosen according to the condi-
tion of the ore. Thus for ores that do not contain more than 10 grammes of gold
per ton and not too large amounts of other chlorine consuming materials, a chloride
solution of 1 to 2%, strength will be suitable. With richer ores somewhat stronger
solutions should be used. This solution, together with muriatic acid somewhat
in surplus relatively to the amount of chloride of lime, and a solution of chloride
of lead to about 1/10th of the amount of chloride of lime, or some other lead com-
pound which with the muriatic acid and chloride of lime solution forms chloride
of lead, is then put into extracting vats with the finely ground ore; free chlorine
will then evolve, superchloride of lead is formed and the gold is extracted as
chloride.
From this chloride the gold is then separated in some known manner, such for
instance as by reducing agents or electrolysis. Similarly the process is carried
or if other chlorine metals than chloride of lead are used, but other chlorine
developing means are then used than chloride of lime and an acid, such for
instance as an electrolysed solution of chlorine metal.
The aforesaid extracting process may be adapted for other than water solutions
of chlorine or bromine compounds.
When the ores are rich in silver, special silver extracting chemicals such as
chloride of sodium hyposulphite etc. are added to the extracting medium.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
The process for extracting gold from gold ores or gold ore waste consisting in
Teaching same with chlorine or bromine-containing or chlorine or bromine-evolv-
ing solutions to which are added before or during the leaching chlorine or bromine
compounds of those metals which with free chlorine or bromine can form higher
and less constant chlorine or bromine compounds viz. superchlorides or super-
chloride.
Dated this Tenth day of August 1897