Year: 1887

page_text: Date of Application, 5th Apr., 1887.
Complete Left, 18th June, 1887.
Complete Accepted, 19th July, 1887.
We, ROBERT HANNAN, of 14 Woodside Place, Glasgow, in the County of Lanark,
North Britain, Merchant, and MATTHEW MILBURN of 4 Cromwell Street, Glasgow
aforesaid, Chemist, do hereby declare the nature of this Invention to be as follows,
that is to say :-
This Invention has for its object the obtaining of zinc from its blende or sulphide
in an improved manner and with considerably less waste by volatilisation than occurs
in existing processes.
In carrying out the Invention the zinc blende or sulphide is not roasted or calcined
as heretofore, but is mixed in a suitably pulverised condition with scrap iron,
preferably malleable scrap iron, or with iron oxide. When iron oxide is used
sufficient carbon to reduce the iron to the metallic state must also be added or applied
in a solid liquid or gaseous form. The inixture is heated in retorts which may
be such as are at present used in smelting zinc but which are preferred to be vertical.
The temperature is gradually raised and causes the reduction of the zinc which
volatilises and may be condensed and collected in the usual way. The sulphur
combines with the iron and any copper present forming a matte or regulus which
may be drawn off in a melted state. With a suitable construction of retort and with
the addition of suitable fluxing materials to promote the fusion of the silicious matter
in the zinc blende, the process may be made continuous.
EDMUND HUNT,
Applicants' Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in Obtaining Zinc from its Blende or Sulphide.
We, ROBERT HANNAN, of 14 Woodside Place, Glasgow, in the County of Lanark,
North Britain, Merchant, and MATTHEW MILBURN, of 4 Cromwell Street, Glasgow,
aforesaid, Chemist, 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, that is to say:-
This Invention has for its object the obtaining of zinc from its blende or sulphide
in an improved manner, and with considerably less waste by volatilisation than occurs
in existing processes.
In carrying out the Invention the zinc blende or sulphide is not roasted, or calcined
as heretofore, but is mixed in a suitably pulverised condition with scrap iron,
preferably malleable scrap irou, or with iron oxide. When iron oxide is used,
sufficient carbon to reduce the iron to the inetallic state must also be added or
applied in a solid, liquid, or gaseous form. The mixture is heated in retorts which
may be such as are at present used in smolting zinc but which are preferred
to be vertical. The temperature is gradually raised and causes the reduction of
the zinc which volatilises and may be condensed and collected in the usual way.
The sulphur combines with the iron and any copper present forming a matte or.
regulus which may be drawn off in a melted state. With a suitable construction of
retort and with the addition of suitable fluxing materials to promote the fusion of
the silicious or other impurities in the zinc blende the process may be made continuous.
In working our improved process we use a retort communicating with a condenser
for collecting the zinc which comes off in vapor. The retort may be similar to those
at present in use for working with calcined zinc ore but the bottom of the retort
is sloped from all sides towards a tapping hole which is provided at the lowest point
for running off the fluid regulus of sulphide of iron and liquid slag in order that the
process may be carried on continuously. We prefer to use a retort provided with
a charging hopper closed with a bell cone like what is used in various metallurgical
furnaces. The retort is charged at intervals until a certain amount of slag and
regulus has accumulated at the bottom and then the tapping hole is opened and
the fluid contents are wholly or partly discharged. We do not restrict ourselves
to the use of any particular form of retort, and only refer to a retort as an example
and for the purpose of explaining clearly the rationale of the process.
The charge may consist of zinc blende in a suitable state of division, iron scrap
(preferably malleable iron) to the amount of about one pound of iron for every
one pound of zinc contained in the charge of ore. Sufficient lime, lime and alumina,
alumina alone, fluor spar, or other fluxing materials are added, the amount and kind
of fluxing material being determined by the quantities of lime, alumina, oxides
of iron, and silica, contained in the ores, and by the ratio in which the basic and acid
bodies stand to one another, the proportions added being in all cases such that the
resulting slag will be quite fluid at the working temperature of the retort.

page_text: Zinc blendes frequently contain varying quantities of lead and copper and in our
process these metals are obtained in forms which are commercially valuable. The
lead sulphide when it occurs in a blende is reduced to metallic lead which largely
collects at the bottom of the retort and lies below the sulphide regulus. The copper
which invariably finds its way into the sulphide regulus, when it is charged in an ore,
is in a form easily extracted by any of the wet processes, for the extraction of copper
from pyrites.
Silver and gold which sometimes accompany zinc blende, are reduced by metallic
iron, and are found in the metallic state below the sulphide regulus; and if lead
is also present these metals alloy with the lead from which they are easily separable.
When the quantity of lead is appreciable, a small quantity of any of the oxides of iron
may be added in quantity varying according to the lead sulphide contained in
the ore, the object being to oxidise a portion of the lead sulphide which then reacts
on the remaining sulphide of lead.
As hereinbefore stated the process may be so far modified that iron ores and such
reducing materials as will yield metallic iron may be used instead of the scrap iron.
In this case the iron ore is mixed with sufficient carbonaceous matter to reduce
the iron oxides, and sufficient fluxing material is added to make an easily fusible slag
with the silicious or other gangue. Excess of carbonaceous matter beyond that
necessary to reduce the iron oxides should be avoided.
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 :-
1 The improved process for obtaining zinc from its blende or sulphide in which
iron is used as a reducing agent substantially as hereinbefore described.
2
The use of iron ore or oxide in combination with carbonaceous matter in
obtaining zinc from its blende or sulphide substantially as hereinbefore described.
Dated this Seventeenth day of June 1887.
EDMUND HUNT,
Applicants' Agent.