IMPROVEMENTS IN THE TREATMENT OF ORES AND METALLIC COMPOUNDS OR RESIDUAL PRODUCTS CONTAINING SILVER, LEAD, OR COPPER, SEVERALLY OR COMBINED, TOGETHER WITH CERTAIN OTHER METALS
Year: 1881

page_text: LETTERS PATENT to Farnham Maxwell Lyte, of the Science Club, Savile
Row, in the County of Middlesex, for an Invention of "IMPROVEMENTS IN
THE TREATMENT OF ORES AND METALLIC COMPOUNDS OR RESIDUAL
PRODUCTS CONTAINING SILVER, LEAD, OR COPPER, SEVERALLY OR COMBINED,
TOGETHER WITH CERTAIN OTHER METALS."
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell Lyte
at the Office of the Commissioners of Patents on the 22nd October 1881.
FARNHAM MAXWELL LYTE, of the Science Club, Savile Row, in the County of
Middlesex, "IMPROVEMENTS IN THE TREATMENT OF ORES AND METALLIC
COMPOUNDS OR RESIDUAL PRODUCTS CONTAINING SILVER, LEAD, OR COPPER,
SEVERALLY OR COMBINED, TOGETHER WITH CERTAIN OTHER METALS."
"
This Invention is nearly allied to that method for which former Letters Patent
were granted to me, No. 2807, 1877, and which I term my "sulphatation" process,
and is suited to the treatment of ores or metallic compounds containing silver, lead,
or copper, either severally or combined, the same being associated with antimony,
or such other metals as are capable of forming volatile chlorides in presence of
hydrochloric acid aided by heat. In my "sulphatation process I recommend
the addition of a small portion of brine or solution of sodium chloride to the ore
during sulphatation in order to fix the silver. I have found that this addition
causes, if the heat be properly moderated, a volatilization of all or any of those
metals having a tendency, like antimony or arsenic, for instance, to form volatile
chlorides with hydrochloric acid at high temperatures, while the other metallic
chlorides formed remain fixed, and that if the quantities of sodium chloride and
sulphuric acid be sufficient and rightly proportioned, all or nearly all of these
metals last referred to may be distilled off and separated.

page_text: The
According to my present improvements the operation is performed as in my
sulphatation process in an oven, stove, hot chamber, or reverberatory furnace.
ore may be calcined or not before treatment, some ores, such as galena containing
antimony, not requiring calcination; others, such as some arsenical and cupriferous
ores, being improved thereby. The ore should be in fine powder, and being mixed
with any suitable chloride, but preferably with common or ground rock salt, is
placed in a reverberatory or muffle furnace in a vessel lined with or made of brick
or some material capable of withstanding the acid and the high temperature, and
there treated with sulphuric acid, as in the sulphatation process. The sulphuric
acid employed need not be stronger than the ordinary chamber acid. The reaction
generates much heat, and antimonious or other volatile chlorides which may be
formed already commence to pass off, but the completion of this volatilization may
be aided by gentle firing. The quantity of salt to be employed should be con-
siderably in excess of that theoretically requisite to develop the hydrochloric acid
necessary for combining with the metals; a quantity equal to the weight of the ore,
or often much less, will generally suffice, but this will vary with the nature of the
ore and whether previously calcined or raw ore be treated. The salt should be by
preference rather in excess of the sulphuric acid employed, equivalent for equivalent.
The heat is applied till the volatile chlorides have escaped as far as may be, and by
this time the mixture having been raked about it will have become completely
dried up.
A like result may be obtained by heating these ores to from 200° to 300° C., whether
previously calcined or not, as may be advisable, and even in lumps or agglomerated
masses in a current of hydrochloric acid gas; or the ore may be treated in the
muffle or furnace by pouring aqueous hydrochloric acid over it under similar
conditions as those above mentioned. A strong solution of ferric or ferrous chloride
may also be used in place of the hydrochloric acid or sulphuric acid and common
salt. Care must be taken so far to moderate the heat as not to volatilize the lead
or silver chlorides whichever of these may be present. After the operation the ores
may be lixiviated if thought advisable with cold water to withraw any soluble
sults, and if sulphuric acid and common salt have been used much sodium sulphate
will thus be extracted. From the residue the lead and silver are obtained, by
brine or by a solution of alkalino-earthy chloride, as already described in the
Specification of my Patent, 1051-1880; or the residue may be smelted for the
metals it contains, as in the last or cold acid treatment No. 4932-1880.
The fumes arising from the furnace treatment above described should be got rid
of by being conducted to a chimney or a suitable condenser, from which the
chloride of antimony may be collected and metallic antimony extracted. Compounds
containing copper and nickel with other metals capable of forming volatile chlorides
may also be treated in this manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Farnham Maxwell Lyte in the Great Seal Patent Office on the
22nd April 1882.
FARNHAM MAXWELL LYTE, of the Science Club, Savile Row, in the County of
Middlesex. "IMPROVEMENTS IN THE TREATMENT OF ORES AND METALLIO
COMPOUNDS OR RESIDUAL PRODUCTS CONTAINING SILVER, LEAD, OR COPPER,
SEVERALLY OR COMBINED, TOGETHER WITH CERTAIN OTHER METALS."
This Invention is nearly allied to that method for which former Letters Patent
were granted to me, No. 2807-1877, and which I term my "sulphatation" process,
and is suited to the treatment of ores or metallic compounds containing silver, lead,
or copper, either severally or combined, the same being associated with antimony,
or such other metals as are capable of forming, in presence of hydrochloric acid
aided by heat, chlorides, volatile at moderate temperatures. In my said "sulpha-
tation"
process I recommend the addition of a small portion of brine or solution of
sodium chloride to the ore during sulphatation in order to fix the silver. I have
since found that this addition may be made by properly moderating the heat to
bring about a volatilization of all or any of those metals having a tendency, like
antimony or arsenic, for instance, to form volatile chlorides with hydrochloric acid
at high temperatures while the other metallic chlorides formed remain fixed, and
that if the quantities of sodium chloride and sulphuric acid be sufficient and rightly
proportioned, all or nearly all of the metals forming the more volatile chlorides may
be distilled off and separated.
The operation is performed, as in my "sulphatation" process, in an oven, stove,
hot chamber, or reverberatory furnace. The ore may be calcined or not before
treatinent; some ores, such as galena, containing antimony not requiring calcination;
others, such as some arsenical and cupriferous ores, being improved thereby. The
ore should be in fine powder, and being mixed with any suitable chloride, but
preferably with common or ground rock salt, is placed in a reverberatory or muffle
furnace in a vessel lined with or made of brick, or some material capable of with-
standing the acid and heat, and is there treated with sulphuric acid as in the
"sulphatation" process. The sulphuric acid employed should not be stronger than
the ordinary chamber acid. The reaction generates some heat, the antimonious or
other volatile chlorides which may be formed already commence to pass off, and
the completion of this volatilisation is aided by gentle firing. The quantity of
salt to be employed should be considerably in excess of that theoretically requisite
to develop the hydrochloric acid necessary for combining with the metals; a
quantity equal to the weight of the ore, or often much less, will generally suffice,
but this will vary with the nature of the ore, and whether previously calcined or
raw ore be treated. The salt should be by preference rather in excess of the
sulphuric acid employed, equivalent for equivalent, and the sulphuric acid used
should be fairly dilute so as not to cause too sudden an evolution of the hydro-
chloric acid from the salt in the gaseous state. The heat is applied till the more
volatile chlorides have escaped as far as may be, and by this time the mixture
having been raked about it will have become completely dried up.
An essential feature of this Invention will therefore be seen to consist in the
utilisation of the different relative volatilities of the chlorides of the various metals,
so that the use of the final heating, whereby the more volatile chlorides are
completely expelled while the less volatile chlorides remain behind, becomes evident.
A like result may be obtained by heating these ores to from 200° to 300° C.,

page_text: whether previously calcined or not, as may be advisable, and even in agglomerated
masses in a current of hydrochloric acid gas; or the ore may be treated in the
muffle or furnace by pouring aqueous hydrochloric acid over it under similar
conditions as those above mentioned.
If a very large proportion of antimony be present in the ore, this process may
be advantageously varied as follows:-The ground ore may be first attacked with
hydrochloric acid aided by heat, which will dissolve the antimony and leave the
lead and silver chlorides for the most part mixed with the gangue. The anti-
monial, liquor which will still hold in solution some lead and silver chlorides, may
be decanted off, and on cooling these lead and silver chlorides become deposited
and may be collected, and if then heated in a muffle or reverberatory furnace
antimonious chloride is driven off if sufficient free hydrochloric acid be already
present. If not there may be added a little common salt and sulphuric acid or
some fresh hydrochloric acid, or the residue may be drained and dried and made
into lumps and heated in a current of hydrochloric acid gas, as above described,
whereby any still adherent antimonious chloride is driven off. A strong solution
of ferric or ferrous chloride may also be used in place of the hydrochloric acid or
sulphuric acid and common salt.
If heated in agglomerated masses in a current of hydrochloric acid gas, the raw
or calcined ore may be agglomerated by means of common salt, and may be
exposed to a current of the said gas in chambers or cylinders maintained at about
the temperature above mentioned, but not sufficiently heated to volatilise or fuse
the lead or silver chlorides.
It will be understood that in all cases care must be taken so far to moderate the
heat as not to volatilise the lead or silver chlorides whichever of these may be
present, but the difference between the temperatures at which these latter begin
to volatilise and those at which the more volatile chlorides of antimony, &c., pass
off is so wide that it is not difficult to prevent their volatilisation by regulating
the temperature. After the operation the ores may be lixiviated, if thought
advisable, with cold water to withdraw any soluble salts, and if sulphuric acid
and common salt have been used much sodium sulphate will thus be extracted.
From the residue the lead and silver are obtained by brine, or by a solution of
alkalino-earthy chloride, as already described in the Specification of my Letters
Patent, No. 1051, of 1880, or the residue may be smelted for the metals it contains,
as described in the Specification of my Letters Patent, No. 4932, of 1880.
The fumes arising from the furnace treatment above described should be got rid
of by being conducted to a chimney or a suitable condenser, from which the
chloride of antimony may be collected and metallic antimony extracted. The
antimonious chloride may be, if desired, condensed by means of a strong solution
of sodium or calcium chloride, or of any one of the soluble alkaline or alkalino-
earthy chlorides. In strong solutions of these chlorides the antimonious chloride
dissolves without precipitation of the oxychloride of antimony, and a clear solution
may thus be obtained from which the metallic antimony may be reduced by means
of zinc or iron, better and more economically than from an acid solution, or from
the muddy precipitate of the oxychloride formed by water. Compounds containing
copper and nickel, with other metals capable of forming in presence of hydrochloric
acid aided by heat chlorides, volatile at moderate temperatures, may also be treated
in this manner.
Having described the nature of my Invention and the manner of performing the
same, I declare that what I claim as my Invention to be protected by the herein-
before in part recited Letters Patent is,―
1st. The treatment of ores and metallic compounds or residual products
containing silver, lead, or copper, either severally or combined, the same being
associated with antimony or other metals capable of forming chlorides more volatile
than the said first mentioned metals, substantially as herein described, whereby
the more volatile chlorides are formed and then volatilised, leaving the less volatile
chlorides of silver, lead, or copper for further treatment.

page_text: 2nd. The condensation of the fumes of antimonions chloride resulting from the
furnace treatment, substantially as above described.
In witness whereof, I, the said Farnham Maxwell Lyte, have hereunto set my
hand and seal, this Twenty first day of April, A.D. 1882.
Witness,
T. W. KENNARD,
Clerk to A. M. & WH. CLARK,
Patent Agents,
53, Chancery Lane.
F. MAXWELL LYTE. (LS.)