Frocess of Treatment of Lead Ores for Obtaining Metallic Lead.
Year: 1899

page_text: Date of Application (in United Kingdom), 18th Nov., 1899
10th Nov 1000
Accented
30th Dec
1000
COMPLETE SPECIFICATION
A Frocess of Treatment of Lead Ores for Obtaining Metallic Lead.
I, ANTONIN GERMOT, of No. 22, Avenue de Courbevoie, Asnières, near Paris,
in the Republic of France, Civil Engineer, 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:-
The object of this invention is a method of treatment of lead ores in order
to obtain, on the one hand, metallic lead containing the whole of the silver
which the ore may contain and, on the other hand, metallic lead free from
silver.
According to a process described in the Specification of British Patent
No. 2883 of 1893 in order to extract the whole of the metallic lead from a quantity
of lead ore it is necessary first to melt the ore in a converter, to blow air into the
melted mass for the purpose of converting it in part into sulphate of lead fumes
while the residuum remains in the form of metallic lead containing all the silver
in the ore.
It is then necessary to re-introduce into this mass of argentiferous
lead the powder of sulphate of lead which has been collected, adding to it fresh
ore and continuing the blowing in of air, or else to introduce the said powder
into another crucible already containing some melted ore.
In the first case white powder of sulphate of lead is again generated which is
afterwards treated like the first and all the sulphate which has been re-introduced
into the bath is transformed into lead together with a portion of the fresh ore
added to it. The result of this is that the whole of the first quantity of ore is
transformed into metallic lead but that lead contains all the silver which was
contained in the ore.
In the second case, the sulphate added to a bath of ore melted separately is
transformed into lead and by the same reactions transforms all the melted ore
into metallic lead. The whole of the first quantity of ore is therefore trans-
formed into metallic lead, but the result is on the one hand, a quantity of lead
containing all the silver of the original ore, and on the other hand, a quantity of
lead containing the silver of the ore to which the sulphate has been added. The
whole of the lead obtained therefore requires to be submitted to the process of
desilverization.
The aim of my invention is, on the contrary, to obtain, on the one hand, the

page_text: whole of the silver in the ore concentrated into a comparatively small quantity
of lead and, on the other hand metallic lead containing no silver.
To this end use is made of a crucible or converter the top of which is furnished
with an eduction pipe leading to a suitable collecting chamber or to several such
chambers the top of the crucible around the orifice of the said eduction pipe being
hermetically closed so as to prevent any entry of air instead of facilitating as much
as possible entry of air as is done in the above mentioned process for obtaining
sulphate of lead fumes.
At starting a first mass of galena is melted in the crucible, and through the
melted mass a current of air is blown either through the bottom or the side of the
crucible or by means of a vertical blast-nozzle entering the molten mass.
The galena rapidly becomes liquefied and the injected air burns part of its
sulphur, producing sulphurous acid and lead, according to the formula:
PbS+20 Pb + SO².
The combustion of the air injected raises the temperature which is maintained
by the continuous addition of fresh quantities of ore.
The lead separates from the sulphurous portion the latter occupying the upper
part and the former accumulating in the lower part of the crucible in a mass
containing the whole of the silver in the ore.
The sulphurous acid escapes from the upper portion carrying off without contact
of external air, a quantity of sulphide of lead free from silver which passes by
the eduction pipe into the collectors where it condenses in the form of a black,
heavy and very fine powder, which is easily collected, even during the course of
the operation, for re-introduction into the same crucible or for introduction into
a similar and separate crucible.
Where the ore treated contains no silver the eduction pipe may be carried
vertically upward to a sufficient height for the sulphide powder to fall back into
the molten mass, in the crucible.
Where the ore treated contains other metals beside lead such for instance, as
silver, the distilled and condensed galena contains no silver, the whole of that
metal remaining in the lead; if therefore the condensed galena be further
separately treated in the same way as the original galena, a very pure lead will
be obtained.
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
I claim is:
-
First: A process of treatment of lead ores for obtaining metallic lead there-
from, consisting in blowing air through a mass of molten sulphide of lead con-
taining contingently silver or other metals, in collecting without contact of
external air the fumes of sulphide of lead which separates from the mass, and in
introducing the said fumes after condensation thereof into another mass of lead
or of lead and sulphide of lead containing no silver or other metals through
which mass a current of air is blown.
Secondly: The modification of the process defined in the first claim the said
modification consisting in causing the fumes of sulphide of lead separated from
the molten mass by the blowing of air therethrough to fall back direct into the
said molten mass substantially as herein before discribed.
W. T. WHITEMAN,
Agent for the Applicant.