Improvements in and relating to the Treatment of Complex Ores containing Zinc and Lead.
Year: 1899

page_text: Date of Application, 22nd Aug., 1899
Complete Specification 1 aft 21st June 1901-Accented. 18th Aug 1900
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Treatment of Complex Ores
containing Zinc and Lead.
We, GUY DE BECU, Chemical Engineer, of 17, Boulevard de la Madeleine,
Paris, France, and THE GENERAL METAL REDUCTION COMPANY LIMITED, Mer-
chants, of 85, Gracechurch Street, in the City of London, England, do hereby
declare the nature of this invention to be as follows:-
This invention relates to the treatment of ores, and more particularly to the
treatment of complex zinc bearing ores.
Ores of this kind are often treated by roasting them together with an alkaline
or earth alkaline chloride salt at a comparatively low temperature; but, besides
occupying a considerable time and requiring a large quantity of fuel, this treat-
ment is, in the case of most of the complex ores or of the ores rich in zinc
compounds, rendered difficult and inefficient owing chiefly to the formation of
fusible zinc chloride which, remaining with the ore, causes the ore to become
pasty and prevents a dead roast thereof.
Now the chief objects of our invention are to obviate these disadvantages and
to facilitate the separation and recovery of the zinc contained in the ores.
According to our invention we submit the mixture of ore and salt to a com-
paratively high temperature and thus drive off the zinc from the ore in the form
of vapours or fumes. For this purpose we smelt the ore and an alkaline or
earth alkaline chloride salt in a cupola furnace in the presence of an excess of
air. The ore prior to this treatment is preferably crushed or pulverized, mixed
with the chloridizing salt and an appropriate binding agent such as pitch or
clay, and compressed into blocks of suitable size for treatment in the cupola.
The vapours and fumes given off, which will contain most of the zinc, copper
and other metals, chiefly in the form of chlorides, and possibly a portion thereof
in the form of oxides, are collected in condensing towers, the metals being
subsequently separated by any convenient means. The greater part of the lead
contained in the ore is reduced to the metallic state, or to a matt, and falls to
the lower and cooler part of the furnace; and may carry with it any silver that
is present.
T: 001 day of August 1899
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: Improvements in and relating to the Treatment of Complex Ores
containing Zinc and Lead.
°
We, GUY DE BECHI, Chemical Engineer, of 17, Boulevard de la Madeleine,
Paris, France, and THE GENERAL METAL REDUCTION COMPANY LIMITED, Mer-
chants, of 85, Gracechurch Street, in the City of London, England, 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:-
This invention relates to the treatment of complex ores containing zinc and
lead chiefly in the form of sulphides for the recovery of metals.
Ores of this kind have sometimes been treated by roasting them together
with a chloride salt of an alkali or of an alkaline earth, at a comparatively low
temperature. Besides occupying a considerable time and requiring a large
quantity of fuel, this treatment by a chloridizing roast is, in the case of most
of the zinc-bearing complex ores, rendered difficult and inefficient owing chiefly
to the formation of fusible zinc chloride which, remaining with the ore, causes
it to become pasty and prevents a
dead roast thereof.
"
وو
Now the chief objects of this invention are to obviate these disadvantages,
to facilitate the separation and recovery of the zinc contained in the ores, and
to combine in one operation the roasting and the smelting of the ores.
"
According to this invention the ore is crushed or pulverized, and mixed with a
sufficient quantity of a chloride salt of an alkali metal or of an alkaline earth
metal to provide the chlorine required by the metals in the ore, (chiefly by the
zinc) for their volatilization as hereinafter described. The quantity of the
chloride salt required, largely depends upon the quantity of the zinc contained
in the ore and generally varies between 30 per cent. and 60 per cent. of the weight
of the ore. A suitable flux which varies according to the nature of the " gangue'
is also added to the mixture of the ore and the chloride salt for the purpose of
forming a proper slag when smelting as hereinafter described. The mixture is
then compressed into blocks of suitable size either with or without an appropriate
binding agent such as pitch, lime or clay. These blocks are then subjected to a
sufficiently high temperature to drive off the zinc from the ore in the form of
vapours or fumes. To effect this driving off the zinc in the form of vapours or
fumes the aforesaid blocks are smelted in a cupola furnace into which air is
introduced at different heights in such manner that in the higher part of the
furnace the mixture of ore and salt is heated in the presence of an excess of
air, whereas in the lower part of the furnace only such an amount of air is
introduced as will be necessary to burn the fuel and smelt the ore.
The vapours or fumes given off will contain most of the zinc together with
some of the lead and other metals, chiefly in the form of chlorides, and possibly
a portion thereof in the form of other salts or of oxides.
These fumes are collected in condensing towers or some other suitable device,
and the metals are subsequently separated from the condensed fumes in any
convenient manner.
"
"
A certain amount of the lead contained in the ore is reduced to the metallic
state or to a matte and falls to the lower part of the furnace. This metallic
lead or matte may carry with it most of the silver present in the ore.
If the amount of lead in the ore does not exceed about 10 per cent., most of it
is volatilized together with the zinc.
The use of the chloride salt is of great importance for the volatilization of the

page_text: metals contained in the ore and for the production of a good slag, as it provides
the necessary base for the formation of an easily fusible double silicate or slag,
and thereby reduces the loss of metals in the slag to a minimum.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is:-
The treatment of complex ores containing zinc and lead for the recovery of
metals by a process which consists in mixing the said ore with a chloride salt
of an alkali metal, or with a chloride salt of an alkaline earth metal, and sub-
jecting this mixture to a combined roasting and smelting operation substantially
as and for the purpose specified.
Dated this 21st der of Tune 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.