Year: 1895

page_text: Date of Application, 26th Apr., 1895
Complete Specification Left, 25th Jan., 1896-Accepted, 25th Apr., 1896

page_text: :
their solution the sulphate is eliminated chemically by means of chloride of calcium
or the like, or preferably. by means of freezing it out. Thus pure sulphate is
obtained.
Or the residue containing the zine is subjected to the ordinary oxidizing roasting,
whereby oxide of zinc is formed. The latter is then again converted into chloride
of zinc either by hydrochloric acid or by other sources of hydrochloric acid such
as sulphuric acid or sulphurous acid in the presence of common salt or other suitable
chlorides or by any other solvent, for instance chloride of calcium.
Or the residue containing the sulphide of zinc is treated with nitric acid in the
presence of other acids such as hydrochloric acid.
The extraction of the chloride of lead is generally done by using warm solutions
from which the chloride of lead is again easily precipitated by slight cooling. Its
precipitation may, of course be also partially done as a sulphate by any soluble
sulphate.
As stated above the same quantity of CuCl, can be used over and over again
for the extraction of great quantities of lead from the ores. Together with the lead
or after the latter, also a certain amount of zinc will be dissolved, and therefore after
a certain time the solution of cuprous chloride will probably contain large quantities
of zinc.
In this case the solution or part of it which is richest in zinc is in the regular
course freed from its contents of copper and lead and of sulphate of soda and then
utilized for the electrolytical manufacture of ziuc. The precipitation of copper
can take place in different ways. Either by metals such as lead or zinc, or as oxide
by means of lime, for instance according to my former Patent No. 18900/1892 or as
Bulphide by means of a sulphide, such as sulphide of lead or as cuprous chloride by
dilution with water or preferably by electrolysis, as in my former Patents
No. 6736/1884, 4626/1888, and 13336/1893.
The chloride of lead obtained by this process is either directly decomposed by
electrolysis, according to my former Patent No. 13336/1893, or more conveniently
decomposed by zinc dust, impure or old zinc thereby forming metallic lead in a
finely divided state and chloride of zinc.
Or the chloride of lead may be converted into other lead combinations, such as
white lead or chromate of lead or peroxide of lead.
The silver contained in the ores is also dissolved and precipitated from its
solutions electrically or by finely divided copper or lead. From the residue of
the roasted ores the gold can also be extracted by free chlorine or by cyanides.
Under all circumstances the cooling of the solutions containing sulphates of
alkali or containing chlorides of lead, more especially of those containing also
chloride of copper can conveniently be effected by simply mixing these solutions
with snow or ice or with solutions of salts like calcium chloride refrigerated to a
very low temperature.
Like mixed sulphides, pure lead and zinc ores, preferably such as contains.silver,
can also be profitably treated as above described.
It is advisable to treat the sulphides first with acids, such as sulphuric, sulphurous
or hydrochloric acid in order to eliminate carbonates and soluble sulphides before
the ores are subjected to chlorination by cupric chloride.
In order to increase the effect of the cupric chloride in the described treatment
and to arrive at a complete lixiviation of ores and materials, especially of those
which contain copper and more especially other metals not forming protochlorides,
such as lead and zinc, or silver, I employ at a sufficiently high temperature a
solution of cupric chloride concentrated as much as possible with or without an
addition of other chlorides, bromides or iodides. After cooling or refrigeration of
the resulting solution the greater part of the copper precipitates in the form of
cuprous chloride. Cupric chloride, if such remains, is practically converted into
protochloride (cuprous chloride) or partially into protosulphide (Cu,S) by means of
fresh ore or readily soluble sulphides, metals, sulphurous acid or by electrolysis;
cuprous chloride, if any be present in the solution, can be precipitated as oxychloride

page_text: of copper preferably by means of warm air or oxygen. The precipitated chlorine
combinations of copper can be utilized for the purpose of further lixiviation by
treating such precipitates with chlorine or acids under assistance of oxygen, either
in the nascent state or not thereby obtaining concentrated lixiviating liquids.
Dated this 26th day of April 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in. and relating to the Treatment of Ores or Materials
Containing Zinc, Lead, and Silver.
I, CARL HOEFFNER, of 2 Helgoländer Ufer, Berlin, formerly of 36 Frank-
furterstrasse, Giessen, in the Empire of Germany, Doctor of Philosophy, do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
Zinciferous lead-ores produce tough or viscous slags in the usual smelting and
cause losses of lead and zinc. Plumbiferous zine ores destroy the muffles by
melting the same and a low percentage of lead (up to 5%) has hitherto been lost."
It is difficult to roast such ores, as the lead contained therein causes too early a
melting and scorifying of the ores so as to render difficult the access of air or gas
to all parts of the ores.
The present invention is designed to avoid such inconveniences by a combined
process.
This combined process consists, as hereinafter more fully explained, in extracting
from such sulphidic ores (containing lead and zinc, silver may also be present) as
much lead as possible and then roasting the ores freed as much as possible from the
lead in order to obtain therefrom the zinc.
Ores containing sulphides of lead and zinc and silver are treated in the following
manner.
The ores are powdered and treated in a stirring vessel with the solution of a
chloridizing agent such as a solution of free chlorine, or of perchloride of iron or
preferably and more advantageously a solution of cupric chloride (CuCl,) at a
moderate temperature so as to dissolve only the silver and lead.
The cupric chloride solution contains a solvent of cuprous chloride, for instance
chiloride of sodium in order to keep in solution the formed cuprous chloride. The
strength of the cupric chloride solution may be chosen so that the solution contains
so much cupric chloride (CuCl₂) as corresponds to a proportion of 4% Cu, and a
temperature of about 60-80° C. has given sufficient results. If ferric chloride
solution is to be employed, the same may contain a quantity of ferric chloride
corresponding to 4-10% Fe.; in this case a temperature of 60-80° C. is also
found suitable.
The cupric chloride is thereby converted into cuprous chloride (Cu,Cl₂) which
can be easily regenerated afterwards into cupric chloride for a continuous extraction
of ores.
The regeneration of the cupric chloride can be effected by free chlorine or by
direct electrolytic action, for instance according to my former Patents No. 6736/1884,
4626/1888 and 22030/1891, but the cheapest way to obtain it consists in bringing
cuprous chloride into contact with oxidizing agents such as nitric acid or more
economically with air or oxygen and acids such as hydrochloric acid or the sources
of the latter, such as sulphuric or sulphurous acid in the presence of suitable
chlorides such as common salt or chloride of potassium or of calcium.

page_text: “The reactions thereby taking place are explained by the following equations:
CugCl + O + 2 HCl = 2 CuCl + HO

page_text: from which the chloride of lead is again easily precipitated by slight cooling. Its.
precipitation may of course be also partially done as a sulphate by adding any
soluble sulphate.
As stated above the same quantity of cupric chloride can be used over and over
again for the extraction of great quantities of lead from the ores. Together with
the lead or after the latter, always a certain small amount of zinc will be dissolved,
and therefore after a certain time the solution of cuprous chloride will probably
contain large quantities of zinc.
In order to utilize also this portion of the zinc the solution or part of it being
richest in zinc is regularly freed from its contents of copper and lead by precipita-
tion and then utilized for the electrolytical manufacture of zinc.
This precipitation of copper can take place in different ways. Either by more
electropositive metals such as lead or zinc in equivalent proportions, or as oxide by
means of lime, for instance according to my former Patent No. 18900/1892 or as
sulphide by means of a sulphide such as sulphide of lead or as a cuprous chloride
by dilution with water or preferably by electrolysis as in my former Patents
No. 6736/1884, 4626/1888 and 13336/1893. On the other hand the precipitation
of lead may take place by cooling or by addition of metallic zinc dust.
The chloride of lead obtained by this process is either directly decomposed by
electrolysis, for instance, in the molten state or according to my former Patent
No. 13336/1893 or more conveniently decomposed by zinc dust, impure or old zine
thereby forming metallic lead in a finely divided state and chloride of zinc.
Or the chloride of lead may be converted in any known manner by suitable
reagents, such as oxides, carbonates, chromates, sulphates into other lead combina-
tions, such as white lead or chromate of lead or peroxide of lead, or may be
utilized in any other way.
The silver contained in the ores is also dissolved. It is precipitated from the
cuprous chloride solutions electrolytically or by finely divided copper or lead.
Finally also the gold can be extracted by free chlorine or by cyanide from the
residues of the roasted mineral.
In order to save cupric chloride it is advisable to treat the sulphides first with
acids, such as sulphuric, sulphurous or hydrochloric acid in order to eliminate
easily soluble substances such as carbonates and soluble sulphides before the ores
are subjected to the wet chlorination preferably by cupric chloride.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. Process for the treatment of ores or materials containing both sulphide of
lead and sulphide of zinc in order to utilize also the zinc of such ores, which
process consists in the wet extraction of the lead from the said ores or materials by
means of a solution of a chloridizing and leaching agent, such as free chlorine,
cupric chloride or ferric chloride, so as to dissolve the lead and to leave as much as
possible of the zinc in the undissolved residue, from which the zinc is then extracted
in any known way, preferably by means of chloridizing or oxidizing roasting of
such residue substantially as and for the purpose set forth.
2. The manufacture of lead compounds or of metallic lead by treating the said
ores or minerals by means of the process characterized in Claim 1 and then
decomposing the chloride of lead thereby obtained after freeing it from the
copper (if copper is present)-electrolytically or chemically by suitable reagents,
such as oxides, carbonates, chromates, sulphates, or preferably precipitating the
chloride of lead from the said solution by cooling the same, which precipitate of
chloride of lead is utilized as such or converted electrolytically or chemically
into other lead compounds or into metallic lead substantially as and for the purpose
set forth.
3. In the process of treating solutions like those characterized in Claims 1 and 2
the utilization of the chloride of zinc accumulating in the solutions by first

page_text: eliminating the copper (if such is present) and lead and then decomposing the
remaining zine solutions substantially as and for the purpose set forth.
4. In the process according to Claims 1-3 the use of cupric chloride solution
for the wet extraction, thereby converting the cupric chloride into cuprous chloride
and then reconverting the latter by chemical action into cupric chloride so as to
repeatedly employ this regenerated solution for the said wet extraction substantially
as and for the purpose set forth.
5. In the process according to Claims 1-4 the extraction of metals other than
lead and zinc from the solution or residues thereby obtained substantially as and
for the purpose set forth.
6. In combination with the process according to Claims 1-5 in order to save a
proportion of the chloridizing solution for the wet extraction the treatment of the
said ores or minerals previously to the said processes with acids so as to dissolve
the easily soluble substances, such as carbonates and sulphides, substantially as and
for the purpose set forth.
11
T
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.