Year: 1897

page_text: Date of Application, 9th Nov., 1897-Accepted, 24th Dec., 1897
20
97
82
41
PbS+ ZnCl₂ =PbCl₂ + ZnS.
The gain will be about 6000 calories. In the last case (in presence of water)
35 on the contrary heat will be liberated when zinc-sulphide and lead-chloride change
their acid radicals forming lead-sulphide and zinc-chloride:
$1
75
112
20

page_text: formation of each substance is stated in thousands. Silver-sulphide, when present
in the ore which is treated in the described manner, is also converted along with the
lead into halogen salt, while all of the other metals usually present in the ore
remain as sulphides and take no active part in the reaction. On the described
reaction the present invention is based, and one of its objects is to provide a prac-
tically efficient method for reducing sulphide ores containing lead or silver, or both.
To this end the invention, generally stated, consists in introducing the ore into a
molten bath of a halogen salt of a metal, especially into a molten chloride bath,
whereby the sulphides of lead and silver of the ore are decomposed, the sulphur
combining with the base of the salt of the molten hath and the halogen radical of
the bath combining with the lead and silver, so that there is produced in the bath
a sulphide of the base of the salt that constituted the bath into which the ore was
placed and halogen salts of lead and silver which may be recovered therefrom.
The process of systematic leaching is adapted to extract the zine and silver salts
from the cooled mass. The lead salt may be extracted by re-crystallization.
Silver and lead may be reduced to the metallic state by the introduction into the
fused mass of a metal, a zinc, all as is hereinafter more fully described and claimed.
Another object of this invention is to provide at the same time a method of pre-
paring the sulphides of most of the metals from their halogen compounds by means
of lead-sulphide or galena by stirring the latter into a molten bath of a halogen
compound of the metal, the sulphide of which is to be prepared.
The lead-zinc ores cannot be reduced by the ordinary processes which exist for
recovering lead and zinc on account of the interference of zinc with the ordinary
processes for smelting lead, as well as on account of the impossibility of distilling
the ores for zinc on account of corrosion of the retort by the lead. In the practice
of this invention the lead and silver are separated from the blende, the lead and
silver are recovered either as chlorides or in the metallic state, and the zinc-blende
is obtained as such even more concentrated, in a manner which I shall now
proceed to describe.
Ground ore is'stirred into a fused mass of a metal chloride free from water.
Zinc-chloride is well suited to this purpose. The reaction commences immediately
and double decomposition takes place between the lead and silver sulphides present.
in the ore and the fused zinc-chloride resulting, as stated above, in the formation
of zinc-sulphide or blende and lead and silver chlorides, both in amount substan-
tially equivalent to the quantity of galena and silver-sulphide present in the ore.
There is thus obtained instead of the original lead-zinc sulphide ore, what may be
called zinc-blende ore containing the amount of zinc-blende which was present in
the ore plus the zinc-blende formed in the reaction; all this mixed with the same
ingredients or impurities, for example, pyrites, FeS. and silicious compounds,
which were contained in the original ore. The lead and silver, which were present
in the ore as sulphides, are now combined with the chlorine that formed part of the
molten chloride of zinc bath thus forming lead and silver chlorides. In other
words, instead of the original lead-zine ore, there is obtained zine-blende in a fused
mass of chlorides of lead and silver together with some zinc-chloride in case the
latter was taken in excess of the equivalent of the lead and silver present in the
ore. The further treatment may be carried on in different ways: First, metallic
zine may be stirred into the fused mass and this metallic zinc reduces the lead-
chloride and silver-chloride to lead and silver, forming zinc-chloride. The lead
and silver thus separated are in a molten state and collect at the bottom of the
vessel and may be drawn off therefrom. Afterward the mass of zinc-blende and
zinc-chloride may be removed from the vessel and permitted to cool, whereupon the
mass may be broken up into comparatively small pieces and systematically leached
with water whereby the zinc-chloride is removed. The solution of zinc-chloride
thus obtained may be concentrated and evaporated to dryness and used again for
making the fused bath of zinc-chloride into which the ground ore is first placed.
Care should be taken that the fused bath of chloride of zinc into which the ground
ore is first placed is substantially free from water. The zinc-blende obtained after

page_text: the leaching process and by the removal of the zinc-chloride and other soluble salts,
which may have been present in the mixture, may be treated for the recovery of
metallic zinc in any known or preferred manner. Second, after the reaction
between the sulphides of lead and silver present in the ore and the fused zinc-
chloride has taken place, as above described, the whole mass is removed from the
vessel and permitted to cool and is leached, whereby the zinc-chloride and silver-
chloride are extracted, it being borne in mind that zinc-chloride in solution
dissolves silver-chloride, and the silver may be recovered by usual or appropriate
methods, afterwards the lead-chloride may be separated from the insoluble matter
by re-crystallization of the former. The lead-chloride obtained by such re-
crystallization may be treated in any preferred or well-known manner for the
recovery of metallic lead. The zinc-blende left may be reduced in any usual or
preferred manner for the production of metallic zinc.
In the foregoing description reference has been made to the introduction of
powdered lead-zine ores into a fused mass or bath of zine-chloride which should be
free from water, but experiment demonstrates that the presence of other chlorides,
as sodium-chloride and potassium-chloride, does not prevent the action of the
fused zinc-chloride upon the lead and silver sulphides of the ore, and the presence
of such other chlorides increases the bulk of the solution and also increases the
fluidity of the fused mass or bath, which is an advantageous feature, because it
facilitates the operation of stirring the powdered ore into the fused mass or bath.
Moreover, zinc-chloride is more conveniently freed from water, which would be
present, for example, after the leaching operation hereinabove referred to, in the
presence of sodium-chloride and potassium-chloride.
In the foregoing description reference has been made particularly to the de-sul-
phurization of galena, but it has also been stated that the halogen salt or salts, as
chloride of zinc, which constituted the bath, was converted into sulphide. Such
conversion into sulphide is useful and the invention may be practiced primarily for
its accomplishment. For example, the introduction of lead-sulphide into a molten
mass or bath of cryolite (double fluoride of aluminum and sodium) results in the
production of lead and sodium fluoride and aluminum-sulphide, which is useful in
the arts.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:
1. The process of treating ores containing lead-sulphide or silver-sulphide or
both which consists in preparing a mass or bath of fused halogen salt capable of
being decomposed by said sulphides, and introducing the ore into, said fused bath
and thereby effecting double decomposition between said sulphides of the ore and
halogen salt of the bath whereby conversion of the lead and silver sulphides of the
ore into halogen salts of lead and silver, and of the base of the halogen salt of the
bath into a sulphide are effected, substantially as described.
2. The process of treating lead-zinc sulphide ores preparatory to the separation
of lead and silver compounds from zine compounds which consists in introducing
the lead-zinc sulphide ore into a mass or bath of fused chlorides capable of being
decomposed by lead and silver sulphides and thereby effecting double decomposition
between the lead and silver sulphides of the ore and chloride of the bath and con-
verting the lead and silver sulphides of the ore into chloride of lead and chloride
of silver and the chloride of the fused bath or mass into sulphide, and permitting
the zinc-sulphide of the sulphide ore to remain in the fused bath or mass, substan-
tially as described.
3. The method of treating ores in which galena is present which consists in
introducing the ore into a fused mass or bath containing zinc-chloride, and thereby
converting the galena into chloride of lead and forming a sulphide of zinc, and
then reducing the formed lead chloride to the metallic state by the introduction of
metallic zinc into the fused bath or mass, substantially as described.

page_text: 4. The process of forming sulphides of metals from such of their halogen com-
pounds as are capable when fused of being decomposed by galena which consists in
introducing galena into a fused bath of the halogen compounds of the metals, and
separating the halogen compound of the lead formed in the reaction from the
formed metal sulphide.
Dated this 22nd day of October 1907
SOLOMON GANELIN.
Boult & Wade,
Agents for the Applicant.