Improvements in the Extraction of Lead with Silver, Gold, or other Metals, from Galena or Sulphides of Lead and Zinc, and from Mattes Refractory Ores. and ог
Year: 1895

page_text: Date of Application, 27th June, 1895
Complete Specification Left, 26th Mar., 1896-Accepted, 9th May, 1896
PROVISIONAL SPECIFICATION.
Improvements in the Extraction of Lead with Silver, Gold, or other
Metals, from Galena or Sulphides of Lead and Zinc, and from
Mattes Refractory Ores.
and
ог
We HENRY ERNEST FRY of 64 Billiter Buildings, Billiter Street, in the
City of London, Mineral Merchant and Smelter, JOHN DAVID, of Llwyndu,
Glais, near Swansea, in the County of Glamorgan, Metallurgical Chemist, and
CARL LE DOUX, of 20 Woodfield Street, Morriston, (R.S.O.) in the County of
Glamorgan, Metallurgist, do hereby declare the nature of this invention to be as
follows:-
or
Nitre cake or sulphate of soda or other salt or salts of soda or potash anthracite or
other carbonaceous matter together with oxide of iron or other ferrugineous matter
When in, a
are mixed in certain or varying proportions and fused in a furnace.
certain stage of fusion the ore or matte to be treated is added. When the separation
of lead has attained certain varying stages and is complete the furnace is tapped in
the usual way and recharged as before. The matte or residue produced is exposed
to the atmosphere for a greater or less length of time when it becomes more or less
completely disintegrated (obviating any crushing) and more or less completely
freed from slag. Before or after its exposure to the atmosphere it is calcined at a
very low temperature and is used over again with a fresh ore charge with or without
an addition of fresh nitre cake or other salt or salts of soda or potash.
Dated this 27th day of June 1895
HENRY E. FRY.
JOHN DAVID.
CARL LE DOUX.
Improvements in the Extraction of Lead with Silver, Gold, or other
Metals, from Galena or Sulphides of Lead and Zinc, and from
Mattes Refractory Ores.
and
or
We, HENRY ERNEST FRY of 64 Billiter Buildings, Billiter Street in the
City of London Merchant and Smelter, JOHN DAVID of Llwyndou, Glais,
near Swansea in the County of Glamorgan Metallurgical Chemist and CARL
LE Doux, of 20 Woodfield Street Morriston (R.S.O.) in the County of
Glamorgan Metallurgist, 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:-
This invention relates more especially to the treatment of those sulphuret ores of
lead which also contain zinc. Such ores, especially when the proportion of zinc is
at all considerable, are very refractory and difficult to deal with.
In the ordinary way ores of this class can only be advantageously treated, by

page_text: mixing them with other ores so that they form but a small part of the bulk,
otherwise in the smelting the losses both of lead and the precious metals, which
such ores frequently contain, becomes excessive.
By this invention sulphuret ores of lead may be smelted without undue loss even
when they contain large quantities of zinc. This is effected by the use of a special
flux prepared from sulphate of soda which is obtainable in the form of nitre cake
or salt cake and oxide of iron which may be in the form of burnt pyrites..
Sulphate of potash in lieu of sulphate of soda might in like manner be employed
excepting that its greater cost generally prohibits its use. The ferruginous matter
may also be in other form.
In the preparation of the flux it is preferred to proceed as follows:-
A charge of nitre cake or bisulphate or sulphate of soda in other form is fused on
the bed of a reverberatory furnace and to it is gradually added with constant
stirring, a certain amount of burnt pyrites in a finely divided state, the proportion
varying with the lead and zinc contents of the ore. A useful mixture being 7 parts
by weight of burnt pyrites to 10 parts by weight of sulphate of soda. The whole
is worked together until complete mixture is obtained and then the partially pasty
and partially fluid flux so formed is drawn out of the furnace and allowed to cool.
Afterwards the flux is broken up into suitably small lumps ready for use. The
furnace bed is preferably formed of basic bricks, though an ordinary fire brick or
slag bottom has been found to answer well.
When the flux is employed in the smelting operation it combines with the oxide
and other compounds of zinc contained in the charge and forms with it a very liquid
slag which is invariably remarkably free from lead and precious metals; it is this
property of fluxing the zinc which renders it particularly valuable in the smelting
of refractory lead ores. The lead ore is preferably treated in the following
manner-It is prepared by crushing it small so that it will pass through a sieve
having say eight holes to the linear inch. The ore thus pulverised is then roasted
at a heat regulated according to the nature of the ore in a reverberatory furnace on
the bed of which it is spread in as thin a layer as practicable.
Whilst it is roasting the ore is constantly turned over with paddles and exposed
to the air until sulphurous fumes cease to be evolved, this operation will usually
extend over many hours.
When the ore is ready it is gradually brought with the paddles up towards the
fire end of the furnace where the heat will cause the ore to cohere sufficiently
to admit of its being drawn out in lumps say from two to four inches long.
In this state the agglomerated ore is withdrawn from the furnace and allowed to
cool. Where the ore contains an excessively high percentage of zinc the calcined
ore may be rendered suitable for the cupola furnace by pressing it into bricks or by
the use of other means than heat to cause the ore to cohere sufficiently.
The smelting may be performed in a cupola furnace; the furnace is charged with
a mixture composed of the prepared ore and the flux already described. Together
with these materials the furnace is fed with fuel in sufficient quantity to melt the
charge. The proportion of flux to the ore varies with the nature of the ore under
treatment; usually for one hundred parts of an average ore of this class, it will be
suitable to employ from 10 to 25 parts of flux.
The object to be attained is that in the smelting operation the oxide and other
compounds of zinc contained in the charge should combine with the flux and pass
into the slag from which it may be recovered and that the resulting slag should be
sufficiently fluid to flow freely. The flux is to be used in sufficient quantity to
attain both these ends. In other respects the smelting operation is performed in
the ordinary manner. The lead is collected in the usual manner of cupola smelting.
Sometimes a little "matte "
separates from the metal; it forms a layer on the
surface of the molten lead. The matte when so formed consists for the most part
of a complex sulphide of iron, zinc and sodium together with a little lead and silver;
it is carefully collected and after a few days. when exposed to the atmosphere
disintegrates, and falls into powder.

page_text: This powder is roasted so as to oxidize the sulphides it contains, and it is either
passed again through the smelting furnace where it replaces an equal quantity of
flux or the zinc and other metals can be extracted as may be preferred.
The lead is treated in the usual way to recover any silver and precious metals
which it may contain.
Having now particularly described and ascertained the nature of our said inven-.
tion and in what manner the same is to be performed we declare that what we
claim is :-
:-
1. Smelting refractory complex lead ores with a flux prepared with nitre cake or
other form of bisulphate or sulphate of soda and burnt pyrites or other form of iron.
oxide.
2. Smelting refractory complex lead ores with a flux substantially as described.
which combines with the zinc of the ore and forms therewith a liquid slag.
Dated thin 97th don of Faba-- 1906
HENRY E. FRY.
JOHN DAVID.
CARL LE DOUX..