IMPROVE- MENTS IN THE TREATMENT OF ORES AND RESIDUAL PRODUCTS CONTAINING ZINC OR ZINC LEAD, SILVER, OR COPPER, SEVERALLY OR COMBINED, AND IN THE RECOVERY OF ZINC AND OTHER METALS THEREFROM
Year: 1877

page_text: LETTERS PATENT to Farnham Maxwell Lyte, of the Scientific Club, Savile
Row, in the County of Middlesex, Esquire, for the Iuvention of "IMPROVE-
MENTS IN THE TREATMENT OF ORES AND RESIDUAL PRODUCTS CONTAINING ZINC
OR ZINC LEAD, SILVER, OR COPPER, SEVERALLY OR COMBINED, AND IN THE
RECOVERY OF ZINC AND OTHER METALS THEREFROM."
aled the 15th May 1877, and dated the 15th February 1877.
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell Lyte at
the Office. of the Commissioners of Patents on the 15th February 1877.
FARNHAM MAXWELL LYTE, of the Scientific Club, Savile Row, in the County of
Middlesex, Esquire. "IMPROVEMENTS IN THE TREATMENT OF ORES AND RESIDUAL
PRODUCTS CONTAINING ZINC OR ZINC LEAD, SILVER, OR COPPER, SEVERALLY OR
COMBINED, AND IN THE RECOVERY OF ZINC AND OTHER METALS THEREFROM."
My Invention relates to improvements in treating ores and materials containing
metals, and obtaining metallic products therefrom.
In carrying my improvements into practical operation I proceed as follows:-The
ore, should it contain sulphurets, should be first calcined to a fairly sweet condition,
and should be finely pulverized; the pulverized materials are then placed in a pan
or vessel made of some material which resists the action of hydrochloric acid, such,
for instance, as pitch pine, stone, stoneware, timber injected with tar or petroleum,
or a stout lead-lined tub will answer, and lasts a very long time. The vessel or tub
should be furnished interiorly with a steam coil for heating purposes, and if large
should be furnished with a mechanical stirrer, also made of material capable of
resisting as much as possible the attacks of hydrochloric acid. Over the ore thus
placed in the vessel or tub the quantity of hydrochloric acid that may be considered
necessary in the particular case, having regard to the materials under treatment, is
then poured, and heat is applied by the steam coil, and the liquid is kept well
stirred or agitated...
1
The strength of the acid employed should be below that at which fumes are given
off in the cold, say 1.02 equal parts of strong commercial muriatic acid and water
answer well, and the quantity of acid to be employed is regulated according to the
quantity of matter capable of chloridization which the material to be operated on

page_text: may contain. When the action of the acid may be considered to be completed all
the zinc present should have passed into solution, together with iron, and also with
other metallic or with any earthy bases which may have become sufficiently
chloridized. The chlorides of lead and silver, if either of these metals were present,
will in some cases be found to have remained partially insoluble in the hot solution.
When the precipitates from the hot solution have been allowed to settle, the clear
solution containing the zinc and other soluble chlorides is decanted while still hot
into another vessel, where on cooling nearly the whole of the dissolved lead chloride
is deposited in a crystalline form. The supernatant liquid is then drawn off from
this deposit, and is introduced into the attacking vessel or tub, which is again
heated; the liquid then takes up a fresh quantity of lead chloride, and is again
decanted back hot into the depositing vat, where on cooling it gives up a fresh crop
of crystals of lead chloride. By this method the gangue or residue of the ore may
be exhausted by successive decantations, heating and cooling of all the lead and
silver chloride it may contain. The silver, if as is frequently the case any is
present, is taken up by and carried over with the lead chloride, and precipitates
with it. This process of decantation may not be always necessary, where for
instance the gangue may not be in such quantity or of such nature as to
interfere with the subsequent treatment of the undissolved precipitate left in the
vessel or tub for the extraction of the metallic lead.
In either of the above cases into the liquor containing the precipitate, whether
with or without the gangue, are plunged one or more bars or pieces of some filings
of zinc; lumps of what is known as hard spelter answer well and are cheaper than
any other form of zinc. Much hydrogen is now disengaged, the spelter dissolves,
augmenting the quantity of zinc chloride in solution, while the silver and lead are
reduced together to the condition of a spongy metallic precipitate.
When the precipitates are deposited they are collected, thoroughly washed with
plain water, and finally agglomerated by pressure into bricks or lumps fit for
smelting. Special care should be taken to thoroughly wash all the soluble chlorides
out of the lead sponge before pressing, and for this purpose it will be found highly
advantageous to perform the operation in a centrifugal machine, such as those used
in sugar refineries. Should much chloride remain with the lead it is liable to cause
waste by volatilization during the smelting, and to injure the furnace by fluxing the
bricks. It now remains to treat the zinc chloride solution, with a view to recover
the zinc in the metallic state. The liquid is first neutralized cold by adding chalk
or carbonate of lime; the liquid is allowed to settle, and the clear portion decanted
off; it is now to be heated to boiling or thereabouts, and carefully elutriated milk
of lime is to be run in, the liquid being kept constantly agitated. The following
points should be observed:-The lime should be added to the liquid zinc chloride
while the latter is kept hot; by this means a denser precipitate which settle more
easily is obtained. The lime should only be added in quantity barely sufficient to
precipitate all the oxide of zinc. It is indeed safer to leave a small trace of zinc
still in solution, so as to ensure there being no excess of lime; the greatest
care should be observed to avoid the formation of any lumps or clots during
precipitation.
The milk of lime should be itself smooth and free from clots, and for further
precaution may be fed through a fine sieve, while the hot zinc chloride should be
kept well stirred and agitated; naked steam from a blow-up driven into the liquid
much assists in this part of the operation. The zinc precipitate should now be well
washed with water by successive decantations, or may be washed in a centrifugal
machine or a filter press, and is finally to be pressed into lumps or bricks in any
machine adapted for this purpose. The principal aim of all this washing and
pressure is to get rid to the utmost extent of all the chloride of calcium contained
in the liquid thereby separated.
The pressed bricks or lumps, consisting of precipitates of more or less impure zinc
oxide, are to be used as a kind of artificial ore like calcined blende or calamine
for the distillation of metallic zinc.

page_text: The above process may be advantageously modified as follows for the treatment
of some silver ores, such as those of Nevada, &c. The ore, pulverized and
calcined or not, as may be found advisable, is placed in the attacking vessel, and
treated as above with hydrochloric acid, and a quantity of calcined galena lead,
sulphate lead, oxide, or other lead compound, in fine powder, and in quantity:
proportioned to that of the silver in the ore, say, 100 of lead to 2 of silver, should
be added. It is a good plan on adding the hydrochloric acid to add a certain
quantity of some material capable of generating chlorine, so as more rapidly to
decompose the sulphurets, and to chloridize any metallic silver or gold, and bring
those metals into solution. Red lead employed in place of or mixed with litharge
or other lead compound employed is a good addition in this respect, the lead
chloride being removed from the gangue by successive decantations, as above,
removes with it all the gold and silver. The lead chloride, and with it the gold and
silver, are reduced as above with metallic zinc, the precious metals are separated
from the lead by any of the usual methods, and the zinc may also be recovered as
above.
It will be found advantageous to use another modification where we have to treat
blende, but containing a low per-centage of galena, and perhaps traces of copper
sulphide. The ore is finely pulverized but not calcined, and is treated with hot
hydrochloric acid. Some kinds of blende hardly dissolve under this treatment,
while the galena with any silver it contains is chloridized, and the chlorides of lead
and silver removed by decantation as above. The copper sulphide and blende for
the most part remain intact, and being then separated and calcined can be treated
for distillation of the zinc, a residuary cupriferous matt remaining behind from
which the copper may be extracted.
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 11th June
1877.
.
FARNHAM MAXWELL LYTE, of the Scientific Club, Savile Row, in the County of
Middlesex, Esquire. "IMPROVEMENTS IN THE TREATMENT OF ORES AND RESIDUAL
PRODUCTS CONTAINING ZINC OR ZINC LEAD, SILVER, OR COPPER, SEVERALLY OR
COMBINED, AND IN THE RECOVERY OF ZINC AND OTHER METALS THEREFROM."
My Invention relates to improvements in treating ores and materials containing
metals, particularly zinc, lead, and silver, and obtaining metallic products therefroin.
In carrying my improvements into practical effect I proceed as follows:-The
ore, should it contain sulphurets, should be first calcined to a fairly sweet condition
and should be finely pulverized. The pulverized materials are then placed in a
pan or vessel made of some material which resists the action of hydrochloric acid,
such for instance as one of pitch pine, stone, stoneware, timber, or other material
varnished, silicated, or injected with tar or petroleum, or even a stout lead-lined
tub will answer and lasts a very long time. The vessel or tub should be furnished
interiorly with a steam coil for heating purposes, and if large should be furnished
with a mechanical stirrer, also made of material capable of resisting as much as
possible the attacks of hydrochloric acid. Over the ore thus placed in the vessel
or tub the quantity of hydrochloric acid that may be considered necessary in the
particular case, having regard to the materials under treatment, is then poured, and
heat is applied by the steam coil and the liquid is kept well stirred or agitated.
The strength of the acid employed should be below that at which fumes are
given off in the cold, say, 102. Equal parts of strong commercial muriatic acid
and water answer well so as to avoid inconvenience to the workmen, and the
quantity of acid to be employed is regulated according to the quantity and nature

page_text: .
of the matters capable of chloridization which the material to be operated on may
contain. When the action of the acid may be considered to be completed all the
zinc present should have passed into solution, together with iron or any other
metallic or earthy bases present which may have become sufficiently chloridized.
The chlorides of lead and silver, if either of these metals were present, will in some
cases be found to have remained partially insoluble in the hot solution.
When the precipitates from the hot solution have been allowed to settle, the
clear solution containing the zinc and other soluble chlorides is decanted while
still hot into another vessel, where, on cooling, nearly the whole of the dissolved
lead chloride is deposited in a crystalline. form. The supernatant liquid is then
drawn off from this deposit, and is redecanted back into the attacking vessel or
tub which is again heated. The liquid then takes up a fresh quantity of lead
chloride and is again decanted back hot into the depositing vat, where, on cooling,
it gives up a fresh crop of crystals of lead chloride. By this method the gangue or
residue of the ore may be exhausted by successive decantations, heating, and cooling
of all the lead and silver chloride it may contain. The silver, if, as is frequently
the case, any is present, is taken up by and carried over with the lead chloride and
precipitates with it. This process of decantation may not be always necessary
where, for instance, the gangue may not be in such quantity or of such nature as
to interfere with the subsequent treatment of the undissolved precipitate left in the
vessel or tub for the extraction of the metallic lead.
In either of the above cases into the liquor containing the precipitate, whether
with or without the gangue, are plunged one or more bars or pieces or some filings
of zinc. Lumps of what is known as hard spelter answer well, and are cheaper
than any other form of zinc. Much hydrogen is now disengaged, the spelter
dissolves, augmenting the quantity of zinc chloride in solution, while the silver and
lead are reduced together to the condition of a spongy metallic precipitate.
When the precipitates are deposited they are collected, thoroughly washed with
plain water, and finally agglomerated by pressure into bricks or lumps fit for
smelting; special care should be taken to thoroughly wash all the soluble chlorides
out of the lead sponge before pressing, and for this purpose it will be found highly
advantageous to perform the operation in a centrifugal machine, such as those used
in sugar refineries. Should much chloride remain with the lead it is liable to cause
waste by volatilization during the smelting, and to injure the furnace by fluxing
the bricks. It now remains to treat the zinc chloride solution with a view to
recover the zinc in the metallic state. The liquid is first neutralized cold by adding
chalk or carbonate of lime. The liquid is allowed to settle and the clear portion
decanted off. It is now to be heated to boiling, or thereabouts, and carefully
elutriated milk of lime is to be run in, the liquid being kept constantly agitated.
The following points should be observed :-The lime should be added to the liquid
zine chloride while the latter is kept hot. By this means a denser precipitate,
which settles more easily, is obtained. The lime should only be added in quantity
barely sufficient to precipitate all the oxide of zinc. It is indeed safer to leave a
small trace of zinc still in solution, so as to ensure there being no excess of lime.
The greatest care should be observed to avoid the formation of any lumps or clots
during precipitation.
The milk of lime should be itself smooth and free from clots, and for further
precaution may be fed through a fine sieve, while the hot zinc chloride should be
kept well stirred and agitated; naked steam from a blow-up, driven into the liquid,
much assists in this part of the operation. The zinc precipitate should now be well
washed with water by successive decantations, or may be washed in a centrifugal
machine or a filter press, and is finally to be pressed into lumps or bricks in any
machine adapted for this purpose. The principal aim of all this washing and
pressure is to get rid to the utmost extent of all the chloride of calcium contained
in the liquid thereby separated, as lime or lime salts will act injuriously on the
retorts.

page_text: The pressed bricks or lumps, consisting of precipitates of more or less impure
zinc oxide, are to be used as a kind of artificial ore, like calcined blende or calamine,
for the distillation of metallic zinc.
The above processes may be advantageously modified as follows for the treatment
of some silver ores, such as those of Nevada, &c. :-The ore pulverized and calcined
or not, as may be found advisable, is placed in the attacking vessel and treated as
above with hydrochloric acid and a quantity of calcined galena lead, sulphate lead,
oxide, or other lead compound, in fine powder and in quantity proportioned to that
of the silver in the ore, say, 100 of lead to 2 of silver, should be added. It is a good
plan on adding the hydrochloric acid to add a certain quantity of some material
capable of generating chlorine, so as more rapidly to decompose the sulphurets and
to chloridize any metallic silver or gold and bring those metals into solution. Red
lead employed in place of or mixed with the litharge or other lead compound
employed is a good addition in this respect; but the peroxide of manganese
bleaching powder, chlorates, nitric acid, or nitrates, &c., may be more or less
advantageously employed. The lead chloride being removed from the gangue by
successive decantations, as above, removes with it all the gold and silver. The lead
chloride, and with it the gold and silver, are reduced, as above, with metallic zinc,
the precious metals are separated from the lead by any of the usual methods, and
the zinc may also be recovered as above.
Having described the nature of the said 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 mixed ores, containing lead, silver, and zinc, so as to effect
the separation of the lead and silver and also recover the zinc in the metallic state,
substantially as described.
2nd. I also claim the production of precipitated lead in the form of bricks and
the conversion into bricks of the crude oxide of zinc, excess of lime being prevented,
all substantially as described.
3rd. I further claim the modification of my improved process where employed
for treating silver ores, substantially as described.
In witness whereof, I, the said Farnham Maxwell Lyte, have hereunto set my
hand and seal, this Seventh day of June, in the year of our Lord One
thousand eight hundred and seventy-seven.
F. MAXWELL LYTE. (L.S.)

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FARNHAM
MAXWELL LYTE, of the Scientific Club, Savile Row, in the County of Middlesex,
Esquire, send greeting :-
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters Patent
bearing date the 15th February, in the year of our Lord 1877, in the 40th year
of Her reign, did for Herself, Her heirs and successors, give and grant unto me,
the said Farnham Maxwell Lyte, Her special license that I, the said Farnham
Maxwell Lyte, my executors, administrators, and assigns, or such others as I, the
said Farnham Maxwell Lyte, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use, exercise,
and vend within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and the Isle of Man, an Invention for "IMPROVEMENTS IN THE TREATMENT
OF ORES AND RESIDUAL PRODUCTS CONTAINING ZINC OR ZINC LEAD, SILVER, OR
COPPER, SEVERALLY OR COMBINED, AND IN THE RECOVERY OF ZINC AND OTHER
METALS THEREFROM."
And whereas, in pursuance and performance of a proviso in the said Letters
Patent contained, I, the said Farnham Maxwell Lyte, did within 6 calendar months
next after the date of the said Letters Patent cause a Specification in writing
under my hand and seal, particularly describing the nature of the said Invention,
and in what manner the same was to be performed, to be duly filed in the Great
Seal Patent Office:
And whereas, since the filing of the said Specification I have observed that the
title of the Patent is wider than the claims, and have discovered certain clerical
errors and errors of description, which obscure the meaning of parts of the
Specification :
I am therefore desirous of amending the title of the Patent so as to make it'
agree with the claims, and of correcting the errors in the Specification.
NOW KNOW YE, that I, the said Farnham Maxwell Lyte, by and with the
leave of Her Majesty's Attorney General, do hereby, for the reasons aforesaid and
for effecting the objects aforesaid, disclaim certain parts of the title of the said
[Price 4d1

page_text: Invention, and amend the Specification in manner more fully herein after appearing,
reference being had to the pages and lines of a copy of the Specification as
printed by the Queen's Printers, and published at the Great Seal Patent Office,
that is to say :-
I strike out the words " zinc or " and the words " or copper" from the title, and
insert the word "and" before the word "silver."
I add a final "s " to each of the words "heating" and "cooling" on line 15,
page 4.
"
I make the sentence ending with the word "contain on line 16, page 4, run on
by inserting the words "inasmuch as" in lieu of the full stop.
"at
I remove the words "for the extraction of the metallic lead" from the end of
the paragraph on line 21, page 4, and insert them after the word " treatment
the preceding line.
I commence a new paragraph with the words " It now remains" at line 35,
page 4.
I strike out the word "barely "at line 43, page 4.
"
I strike out the whole of the sentence beginning "It is indeed "at line 43, and
ending with the words "excess of lime on line 44, page 4.
I strike out the words "contained in the liquid thereby separated" at lines 54
and 55, and insert the words "in some cases" after the word "will" at line 55,
page 4.
I insert a comma after the word "galena,” and a byphen between the words "lead
sulphate," and likewise between the words "lead oxide" at lines 7 and 8, page 5.
Lastly. I insert the word "injurious" before the word "excess" in the second
claiming clause at line 28, page 5.
'
And in order that it may be clearly understood what is the Invention which I
now consider to be secured by the hereinbefore in part recited Letters Patent, I
shall proceed to repeat (omitting preamble and testing clause) my said Specification
as proposed to be amended by this present Disclaimer and Memorandum of Alteration
as follows:-
:-
NOW KNOW YE, that I, the said Farnham Maxwell Lyte, do hereby declare
the nature of the said Invention for "Improvements in the Treatment of Ores
" and Residual Products containing Zinc, Lead, and Silver, severally or combined,
"and in the Recovery of Zinc and other Metals therefrom," 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 :-
tr
My Invention relates to improvements in treating ores and materials containing
"metals, particularly zinc, lead, and silver, and obtaining metallic products
"therefrom.
"
"
"
"In carrying my improvements into practical effect I proceed as follows:-The
"ore should it contain sulphurets should be first calcined to a fairly sweet
condition, and should be finely pulverized; the pulverized materials are then
placed in a pan or vessel made of some material which resists the action of
hydrochloric acid, such, for instance, as one of pitch pine, stone, stoneware,
" timber, or other material, varnished, silicated, or injected with tar or petroleum,
" or even a stout lead-lined tub will answer, and lasts a very long time. The
"vessel or tub should be furnished interiorly with a steam coil for heating purposes,
" and if large should be furnished with a mechanical stirrer also made of material
capable of resisting as much as possible the attacks of hydrochloric acid over the
ore thus placed in the vessel or tub. The quantity of hydrochloric acid that may
" be considered necessary in the particular case, having regard to the materials
"under treatment, is then poured and heat is applied by the steam coil, and the
liquid is kept well stirred or agitated.
"The strength of the acid employed should be below that at which fumes are
i given off in the cold, say, 1·02. Equal parts of strong commercial muriatic acid
and water answer well so as to avoid inconvenience to the workmen, and the

page_text: "
"quantity of acid to be employed is regulated according to the quantity and nature
" of the matters capable of chloridization which the material to be operated on may
"contain. When the action of the acid may be considered to be completed all the
"zinc present should have passed into solution together with iron or any other
"metallic or earthy bases which may have become sufficiently chloridized. The
"chlorides of lead and silver, if either of these metals were present, will in some
cases be found to have remained partly insoluble in the hot solution.
"When the precipitates from the hot solution have been allowed to settle the
"clear solution containing the zinc and other soluble chlorides is decanted while
"still hot into another vessel, where on cooling nearly the whole of the dissolved
"lead chloride is deposited in a crystalline form. The supernatant liquid is then
"drawn off from this deposit and is re-decanted back into the attacking vessel or
tub, which is again heated. The liquid then takes up a fresh quantity of lead
chloride, and is again decanted back hot into the depositing vat, where on cooling
"it gives up a fresh crop of crystals of lead chloride. By this method the gangue
"or residue of the ore may be exhausted by successive decantations, heatings, and'
coolings of all the lead and silver chloride it may contain, inasmuch as the silver
" if, as is frequently the case any is present, is taken up by and carried over with
"the lead chloride and precipitates with it. This process of decantation may not.
" be always necessary where, for instance, the gangue may not be in such quantity*
or of such nature as to interfere with the subsequent treatment for the extraction
"of the metallic lead of the undissolved precipitate left in the vessel or tub.
"
#t
"In either of the above cases into the liquor containing the precipitate whether
"with or without the gangue are plunged one or more bars or pieces or some filings
"of zinc. Lumps of what is known as hard spelter answer well and are cheaper
"than any other form of zinc. Much hydrogen is now disengaged; the spelter
" dissolves augmenting the quantity of zinc chloride in solution, while the silver
" and lead are reduced together to the condition of a spongy metallic pre-
cipitate.
"
"
"When the precipitates are deposited they are collected, thoroughly washed
"with plain water, and finally agglomerated by pressure into bricks or lumps fit
for smelting. Special care should be taken to thoroughly wash all the soluble
chlorides out of the lead sponge before pressing, and for this purpose it will be
"found highly advantageous to perform the operation in a centrifugal machine,
"such as those used in sugar refineries. Should much chloride remain with the
lead it is liable to cause waste by volatilization during the smelting and to injure
"the furnace by fluxing the bricks.
"
"
"
It now remains to treat the zinc chloride solution with a view to recover the
"zinc in the metallic state. The liquid is first neutralized cold by adding chalk
or carbonate of lime. The liquid is allowed to settle and the clear portion
"decanted off. It is now to be heated to boiling or thereabouts and carefully
"elutriated milk of lime is to be run in the liquid, being kept constantly agitated.
"The following points should be observed:-The lime should be added to the liquid
"zinc chloride while the latter is kept hot. By this means a denser precipitate,
"which settles more easily is obtained. The lime should only be added in
quantity sufficient to precipitate all the oxide of zinc. The greatest care should
" be observed to avoid the formation of any lumps or clots during precipitation.
"The milk of lime should be itself smooth and free from clots, and for further
precaution may be fed through a fine sieve, while the hot zinc chloride should
" be kept well stirred and agitated; naked steam from a blow-up driven into the
liquid much assists in this part of the operation. The zinc precipitate should
now be well washed with water by successive decantations, or may be washed in
a centrifugal machine or a filter press, and is finally to be pressed into lumps or
"bricks in any machine adapted for this purpose. The principal aim of all this
washing and pressure is to get rid to the utmost extent of all the chloride of
"calcium, as lime or lime salts will in some cases act injuriously on the retorts.
"The pressed bricks or lumps consisting of precipitates of more or less impure
"
<f
<
65
rs
tr

page_text: " zinc oxide are to be used as a kind of artificial ore like calcined blende or
"calamine for the distillation of metallic zinc.
"
"
"
"The above processes may be advantageously modified as follows for the
" treatment of some silver ores, such as those of Nevada, &c. The ore pulverized
" and calcined or not, as may be found advisable, is placed in the attacking vessel
" and treated as above with hydrochloric acid and a quantity of calcined galena,
lead-sulphate, lead-oxide, or other lead compound in fine powder and in quantity
proportioned to that of the silver in the ore, say 100 of lead to 2 of silver
"should be added. It is a good plan on adding the hydrochloric acid to add a
"certain quantity of some material capable of generating chlorine so as more
rapidly to decompose the sulphurets and to chloridize any metallic silver or
gold and bring those metals into solution. Red lead employed in place of or
"mixed with the litharge or other lead compound employed is a good addition in
"this respect, but the peroxide of manganese, bleaching powder, chlorates, nitric
acid, or nitrates, &c., may be more or less advantageously employed. The lead
"chloride being removed from the gangue by successive decantations as above
removes with it all the gold and silver. The lead chloride, and with it the
gold and silver, are reduced as above with metallic zinc, the precious metals
are separated from the lead by any of the usual methods, and the zinc may also
"be recovered as above.
"
"
«
"
"
"
"
<
Having thus described the nature of the said Invention, and the manner of
performing the same, I declare that what I claim as my Invention to be protected
by the hereinbefore in part recited Letters Patent is,―
"1st. The treatment of mixed ores containing lead, silver, and zinc, so as to
" effect the separation of the lead and silver, and also recover the zinc in the
"metallic state, substantially as described.
"2nd. I also claim the production of precipitated lead in the form of bricks and
" the conversion into bricks of the crude oxide of zinc, injurious excess of lime
being prevented, all substantially as described.
"
"3rd. I further claim the modification of my improved process where employed
" for treating silver ores, substantially as described.
In witness whereof, I, the said Farnham Maxwell Lyte, have hereunto set my
hand and seal, this Twenty ninth day of November, in the year of our Lord
One thousand eight hundred and eighty one.
I hereby grant my fiat, giving leave to the above named Farnham Maxwell
Lyte, to file in the Office of the Commissioners of Patents for Inventions, with
the Specification to which the same relates, the above written Disclaimer and
Memorandum of Alteration. And I hereby certify that notice of the application
for leave to file the said Disclaimer and Memorandum of Alteration has been
advertised in the London Gazette, the Commissioners of Patents Journal, the
Times, the Daily Telegraph, the Standard, and the Newcastle Daily Journal.
Dated this second day of December 1881.