Improvements in the Treatment of Complex Sulphide Ores and Apparatus therefor.
Year: 1897

page_text: Date of Application, 15th July, 1897-Accepted, 30th Oct., 1897
COMPLETE SPECIFICATION.
Improvements in the Treatment of Complex Sulphide Ores and
Apparatus therefor.
I, FRANCIS ELLERSHAUSEN, of 24, Green Street, Blackfriars, in the County of
London, Gentleman, 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:
-
My invention relates to improvements in the treatment of complex sulphide ores.
Among the various methods for treating the said ores which have already been
patented may be mentioned those described in Bartlett's British Patent No. 12322
of 1889, Biewend's British Patent No. 15761 of 1894, Hannan's British Patent
No. 5029 of 1887 and Picher's United States Patent No. 554,725 of 1896. My
method, however, entirely differs from all these not only in the way of treatment
and in the apparatus employed but also in the nature of the products obtained. I
would here remark that by the term "complex sulphide ores "I mean such ores
which contain a considerable amount of lead and zinc sulphides and which for
reasons well understood by metallurgists cannot be smelted with any advantage
in the ordinary way not even after being roasted unless the zinc or nearly all of
it is eliminated before smelting.
The elimination of the zinc and simultaneous reduction of the metallic lead in
blast furnaces by the agency of metallic iron or iron ore has been attempted for
the last half century and from the above named patent of Biewend would appear to
be still under consideration. According to Hannan's Patent the refractory ore is
treated with an admixture of iron ore and carbon and heated in retorts so as to
drive off the zine vapours. While this method no doubt accomplishes the object
it cannot be held to do so commercially. However no method appears to be
practised to any large extent except the old one, viz.: roasting the ore and then
leaching it with an acid, to obtain a zinc salt in solution. Thus the elimination
of the zinc prior to smelting the ore has been effected.
The object of my invention is also the elimination of the zinc from complex
sulphide ores prior to the smelting of the lead.
My method of procedure is as follows: viz:
I charge a heated reverberatory, a revolving or other suitable furnace (that is to
say, a furnace in which the charge is heated by the flame of a fireplace) with the
refractory ore to be treated, mixed with oxide of iron or of manganese (or an ore
which contains either one or both of these oxides) and carbon, the proportions
depending on the constituents of the ore, the usual proportions being 100 parts of
ore, 50 parts of oxide of iron and 25 parts of carbon. Full bright red heat is
maintained the whole time the charge is in the furnace.
Fumes of lead and zinc as well as sulphurous acid are produced and leave
the furnace with the fire gases. These fumes are brought into contact with air and
water in suitable chambers or vessels, the result of which is that the zinc is sulphat-
ized and brought into a soluble form, whilst the lead is precipitated or deposited in an

page_text: insoluble form. The separation of the zinc can thus be effected in a most econom-
ical way by obtaining the lead compounds as a solid and the zinc compounds as a
liquid by this simple treatment.
I prefer to employ an exhauster, which draws the fumes, fire gases and air from
the furnace into an air-tight chamber or tank, partially filled with water and
secures a thorough agitation and commixture.
A suitable arrangement of tank for effecting this separation of the zinc and lead
is illustrated in the accompanying drawing, in whica:-
Figure 1 is a longitudinal section of the tank; and,
Figure 2 a section of the same on the line 2-2 Figure 1.
a is the tank which contains water and is entirely closed with the exception
of openings b, c at its ends, the opening 6 which is in the form of a rectangular slit
the width of the tank serving for the admission of the fumes from the furnace
and the opening c being connected to a fan or exhauster (not shown). d is a wall
or bridge for deflecting the fumes under the surface of the water.
The fan or exhauster draws the fumes and air from the furnace through the
opening b, underneath the bridge d and through the upper part of the water so as
to violently agitate the surface thereof and form a spray a circulation of the water
being at the same time created thereby causing the whole of the water to be
brought into contact with the fumes and air. The sulphurous acid in the fumes in
combination with the air and water produces acid and converts the zinc oxide into
soluble zinc sulphate, which remains in solution in the tank while the lead fumes
are condensed and precipitated and remain as insoluble compounds at the bottom
of the tank. The quantity of air drawn in by the exhauster should be sufficient
to fully oxidize the sulphurous fumes and form acid and if sufficient air cannot
be conveniently drawn in by the exhauster the water in the tank may be slightly
acidulated with sulphuric acid. The whole contents of the tanks are then drawn off
and the solid parts allowed to settle and the solution of zinc sulphate after being
removed may be treated by any known means for the production of a commercial
article. c is a pipe for supplying water to the tank and f is a pipe provided with
a cocky an opting into the tank at the bottom thereof for discharging the con-
tents when required. h is a pipe opening into the tank near the surface of the
water and having a glass tube i to serve as a water level indicator and is a pipe
connecting the pipes f and h, the said connecting pipe j being advantageously
employed for assisting the circulation of the water in the tank.
The deposit from any fume; that may have been condensed and deposited when
passing from the furnace before reaching the tank is collected and put into the
tank at any convenient time, but in such proportions as to secure their conver-
sion into soluble sulphate of zinc, that is to say, the quantity of deposit must be
in such proportion to the quantity of free sulphurous acid in the tank as will
ensure its sulphatization.
I am aware that many methods have been proposed and also practised by which
fumes have been brought into contact with water for the purpose of condensing the
same but the success of my process depends upon its being so conducted as to
secure the sulphatization of the zinc, so that it may be separated in a soluble form.
The insoluble precipitate consisting of lead compounds, some silver and a small
percentage of impurities after being dried, is 'mixed with the residue of a furnace
charge after the elimination of the lead and zinc fumes whilst the charge is in a
fused condition and it agglomerates with the charge and forms an excellent
material. containing all the valuable metals in the original ore except the zinc
ready for direct smelting in the blast furnace.
Instead of putting the charge previously mixed with oxide of iron or of man-
ganese (or an ore containing one or both of these oxides) and carbon in the furnace
as above mentioned I may put the ore into the furnace without any admixture
and then add the mixture of oxide and carbon as soon as the ore charge is heated. It
is preferable not to add the whole of the oxide of iron or of manganese and carbon

page_text: ecessary for the reaction of the whole charge but to add the same gradually as
equired for continuous reaction.
When the oxide of iron does not contain any silica and the refractory ore under
reatment contains less than is usually the case in such ores the residue cannot be
used per se.
In this case silica could be added and then fused for the purpose
of agglomerating the collected lead fumes, but I prefer to proceed as follows,-I
add to the unfused residue a fresh charge of ore and carbon the mixture being then
created as above described. Should the residue again remain unfused for want of
ilica, another charge of ore and carbon can be added by which time silica from the
re has probably collected in sufficient quantity to assist the fusion of the residue.
By conducting this process under conditions such as those mentioned, I not only
considerably reduce the quantity of iron used but I also enrich the residue in
valuable metals proportionately whilst the collected lead fumes from the previous
charges would double or treble their richness in lead and thereby save expense in
the subsequent smelting in the blast furnace in the same proportion.
my said
Having now particularly described and ascertained the nature of
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The described process for the treatment of complex sulphide ores, such proces:
consisting in heating an admixture of the ore with oxide of iron or of mangane w
(or an ore containing one or both of these oxides) and carbon in a reverberatory,
a revolving or other suitable furnace in which the charge is heated by the flame of
a fireplace so as to volatilize the lead zinc and sulphur, sulphatizing the zinc fumes
and obtaining a solution thereof and agglomerating the lead compounds obtained
with the fused residue, substantially as described.
2. In the treatment of complex sulphide ores, heating an admixture of the ore
with oxide of iron or of manganese (or an ore containing one or both of these
oxides) and carbon in a suitable furnace so as to 'volatilize the lead, zinc, and
sulphur, the zinc being then sulphatized so as to bring it into solution and separate
it, substantially as described.
3. In the treatment of complex sulphide ores agglomerating with the fused
residue the precipitated lead compounds, substantially as described.
4. In the treatment of complex sulphide ores sulphatizing the zinc and pre-
cipitating the lead compounds by causing the fumes generated by treatment in a
furnace to pass into a tank partially filled with water, substantially as described.
5. In a process for the treatment of complex sulphide ores substantially such as
described placing in the tank the deposit from any fumes which have been con-
densed and deposited whilst passing from the furnace, substantially as described.
6. The improved tank for sulphatizing the zinc fumes and precipitating the lead
compounds arranged for operating substantially as hereinbefore described.
T.... 1907
G. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.