JMPROVEMENTS IN THE PROCESS OF AND APPARATUS FOR THE TREATMENT OF GOLD AND SILVER ORES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Lorentz Albert Groth at the Office
of the Commissioners of Patents on the 20th December 1882. A communi-
cation to him from abroad by the Campbell Mining and Reducing Company,
of the City,, County, and State of New York, United States of America.
LORENTZ ALBERT GROTH K.G.V, Civil Engineer and Managing Director of The
Universal Inventors and Patentees Financial Company Limited 30 Finsbury
Pavement, London E.C. "JMPROVEMENTS IN THE PROCESS OF AND APPARATUS
FOR THE TREATMENT OF GOLD AND SILVER ORES" A communication to me from
abroad by the Campbell Mining and Reducing Company, of the City, County, and
State of New York, United States of America.
This invention has reference to an improved process of treating ores containing
gold and silver, and the invention consists in subjecting the ores in a pulverized
state first to the roasting process of a desulphurizing furnace, in case it should be
necessary, and after they have been so treated, to the action of a bath of molten
lead not for the purpose of amalgamating the metals, but for the purpose of mixing
the mass of pulverized ores with the lead in order to prepare the ores for more
rapid and successful smelting in a smelting furnace.
When the ores are of poor quality, the lead containing the metals is run off from
the smelting furnace and returned to the lead bath, where it is mixed with a fresh
supply of ores, after which the ore charged with lead is subjected to the operation
of smelting, and the process of mixing and smelting is then repeated until the lead
becomes well charged with the precious metals, after which it is separated from the
metals by the operation of cupelling.
This process is adapted for treating refractory orès containing gold and silver
either singly or combined as the case may be.
If the ores to be treated contain a small quantity of sulphur and base metals,.
they are first pulverized and then subjected to the roasting action of a desul-
phurizing furnace
For this purpose the ores are passed once or twice through an oxidizing fire, they
being first thrown by an injector in an upward direction so that the lighter particles
are conducted off at the top of the shaft, while the heavier particles are dropped
and passed a second time through the flame and then deposited in the pit below.
The lighter ore particles are conducted from the main shaft of the furnace through
a connecting tube to a series of settling chambers, some of which are connected by
ntermediate vertical tubes, which are provided with water spray apparatus, the
inest particles being finally conducted through a channel, having an exhaust

page_text: apparatus and collected in a water tank at the end of the series or settling
chambers.
The oxidizing flame is obtained from a hydro-carbon injector of any improved
construction, which is fed with hydro-carbon from a suitable tank, and with steam
from a steam boiler.
The ores thus treated are conveyed by a spiral or other conveyer into a vessel.
containing molten lead, said vessel having a neck extending at one side of the
vessel.
The lead is kept in molten state in the vessel by a furnace arranged below it.
The ores are charged into the bath of molten lead through the neck by means of
a reciprocating piston by which the charge of pulverized ore is fully immersed into
the molten lead in the vessel, the charge being thus compelled to pass in a minutely
divided state through the body of the lead to the surface of the same, upon which
it floats and is then taken up by means of shovels and passed into a smelting
furnace, which is arranged close to the lead bath.
The smelting furnace is provided at the lower part with tuyeres and with a slag
hole just below the same.
The lead which has absorbed the precious metals during the process of smelting.
is run off through a discharge hole and is then returned to the lead bath where it
is again mixed with ore.
This operation is continued until the molten lead is well charged with, the
precious metals.
The lead is then taking to the cupelling furnace, where it is separated from the
other metals by the well known process of cupelling
The process just described is specially adapted for ores containing gold, together
with sulphur and base metals.
When the refractory ores contain gold and silver instead of gold alone, the same
process is gone through with; except that cupelling should be more frequent as the
lead will not hold as large per centage of gold and silver as of gold alone.
Owing to the affinity of the gold and silver for lead, refractory ores which do
not contain any or enough lead to make them good smelting ores can be treated
to greater advantage by thus adding lead to the pulverized ores preparatory to
smelting.
By this treatment the ores are put in such a condition as to be successfully treated.
in the smelting furnace so that nearly all the gold and silver contained therein can
be removed without difficulty
As the lead is regained after cupelling and can be used over and over again, the
process is not an expensive one.
Such ores as do not require to be passed through the roasting furnace are
pulverized & passed directly to the lead bath and from the same to the smelting
furnace and thence to the cupelling furnace..
•
In this connection it may be stated that the process of amalgamating ores by
means of molten lead and subsequently separating the metals by the process of
cupellation, is well known, but, this is not the object of this invention, which is
mainly intended to prepare refractory ores for successful treatment in the smelting
furnace so as to obtain as great a per centage of the precious metals as possible
therefrom
This can only be accomplished by the repeated mixing of the ore containing the
precious metals with molten lead and then subjecting the ore charged with lead to
the smelting operation then returning the lead containing the precious metal to the
bath and repeating said steps of mixing and smelting until the lead contains a
sufficient amount of precious metal to warrant the operation of cupellation.