AN IMPROVED MODE OF OPERATING IN THE SEPARATION OF ALL OR EITHER OF THE METALS, LEAD, ZINC, SILVER, OR COPPER, IN MIXED ORES OR METALLIC MIXTURES, BY MEANS OF ACIDS, BRINE, AND CERTAIN OTHER REAGENTS
Year: 1879

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, send greeting:
WHEREAS Her Most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty second day of January, in the year of our Lord
One thousand eight hundred and seventy nine, in the forty second year of Her
reign, did for Herself, Her heirs and successors, give and grant unto ine, 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
Isle of Man, an Invention for "AN IMPROVED MODE OF OPERATING IN THE
SEPARATION OF ALL OR EITHER OF THE METALS, LEAD, ZINC, SILVER, OR COPPER,
IN MIXED ORES OR METALLIC MIXTURES, BY MEANS OF ACIDS, BRINE, AND
CERTAIN OTHER REAGENTS:
"
And whereas, in pursuance and performance of a proviso in the said Letters
Patent contained, I, the said Farnham Maxwell Lyte did, within six 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 ascertained that the
description of the process and the claims made extend too far, particularly in
relation to the separation of antimony and bismuth from ores or metallic mixtures,
I am therefore desirous of confining the description and claims within narrower
limits, and of disclaining so much of the process as is described and claimed with
I Price Ad

page_text: of
reference to the extraction of antimony or bismuth, and of otherwise amending the
Specification to make it consonant with such alterations, and correcting two
clerical errors in the text of the Specification:
A
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, 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 from and including the words "the ultimate separation," at line 15,
page 3, down to and including the word "retained," on line 19, page 3.
I also strike out the whole of the sentence beginning at line 42, page 3, and
ending with the word "brine" on line 46, page 3. I also strike out the remainder
of the paragraph from and including the word "from," on line 1, page 4. I also
sirike out the whole of the paragraph commencing at line 36 and ending at line 48,
page 4. I also strike out the words "mixed with antimony or bismuth, if either of
these metals be present," at lines 42 and 43, page 6.
I also strike out the whole of the paragraph commencing at line 3 and ending at
line 12, page 7, and I strike out the word "antimonial" at line 15, page 7.
I also strike out line 52, page 7, and renumber the remaining advantages
consecutively. I also strike out the words "any traces of precipitated antimony as
well as from," at lines 2 and 3, page 8, and I substitute the word three" for the
word "four," at line 8, page 8.
"
I also strike out the whole of lines 15, 16, 17, and 18, on page 8. I also strike
out from the second claiming clause the words "antimony or bismuth mixed with
lead, or at lines 25 and 26, page 7.
"
word
I also substitute the word "fifteenth" for the "fifth," at line 49, page 5, and add
a final "8" to the word "Specification," at line 1, page 7.
shall
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 proceed to repeat (omitting preamble and testing clause) my said Specification
as 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, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement,
reference being had to the three accompanying Sheets of Drawings, and to the
letters and figures marked thereon, that is to say,
This Invention relates in part to improvements founded upon those described in
the Specifications of my former Letters Patent, dated respectively the Fifteenth
February, One thousand eight hundred and seventy seven, and the Twenty third
July, One thousand eight hundred and seventy seven.
is
It relates, firstly, to a process of continuous, methodical, and alternate treatment
as applied to minerals and certain metalliferous compounds, whereby metals
therein contained such as lead, zinc, silver, or copper may be ultimately separated
therefrom, as hereinafter more fully described; secondly, this Invention relates
to the application in the special manner about to be described of acids followed
by brine and certain other reagents.
.
In carrying my improved process into practical operation, I employ apparatus
consisting of a set of vessels suitably disposed, so as to be able to effect a series of
decantations in regular and successive order, and in such a manner that each lot of
acid may be made on the one hand to pass successively over two or more lots of
ore, the result of which is that the said acid becomes more completely saturated

page_text: are
.
and neutralized by the soluble and attackable constituents of the ore, while on the
other hand each lot of receives treatment by at least two acid solutions, that is
to say, first, when raw and more easily attacked it is treated by a partially
saturated acid which has been already used in a previous attack; and secondly,
when having lost part of its soluble constituents it has become less easily attackable,
it is treated a second time, but with fresh acid, which has not yet acted on any
previous lot of ore. The extraction of the metals is thus made more complete.
The insoluble sulphate or chloride of lead remaining with the gangue and retaining
the silver which the ore may contain is successively extracted by one or more
boilings or heatings in strong brine, which is made completely to take up and
carry over into another vessel, suitably disposed, all the dissolved lead and silver,
and deposit them there as crystralline chlorides on cooling.
In some cases the brine may be with advantage acidulated. About one or
two per cent. of acid relatively to the quantity of brine will usually be found
sufficient.
By this mode of treatment, while I obtain a considerable economy in the
quantity of acid employed, I also (which is very important) carry over with the
chlorides of zinc and other bases forming soluble chlorides or sulphates the least
possible proportion of lead or silver, these being only slightly soluble in well
neutralized solutions of zinc and other bases (which are conventionally, but perhaps
strictly speaking, rather improperly distinguished from the alkalies, or the alkaline
earths as metallic bases), and remaining consequently with the gangue in the
attacking vessel. These salts of lead and silver when treated with hot or boiling
brine dissolve therein as chlorides, no matter whether they may be originally.
present as sulphates or chlorides. It here becomes necessary to make a few remarks
relating to the solubility of silver and lead chlorides in brine, and the mode of
separating them.
BO
to
A
brino at 10° to 12° 0, about 000 of allver, to one thousand of
▲
I have ascertained that lead chloride is soluble in boiling saturated solution of
sodium chloride (brine) to the extent of about 1-35 parts (=1 part of metallic lead)
to twenty five of boiling brine, whereas on cooling down ordinary temperatures,
most of the chloride of lead crystallizes out, until no more than about one of
metallic lead to eight hundred or one thousand of brine remains in solution. Silver
on the other hand is soluble in the same liquid to the extent of about 0.75 parts of
silver under the form of silver chloride, to one thousand of brine at 25° to 26° C.,
and about double that quantity at a boiling temperature. The presence of lead
chloride in the brine seems rather to increase this rate of solubility of silver as silver
chloride. The solution of silver chloride in brine appears to be peculiarly liable to
what is termed supersaturation, so much that it will often be found that brine
saturated hot with silver chloride will remain clear on cooling, until some determining
cause, such as the addition of an atom of solid silver chloride, intervenes, when
immediately the whole liquid will turn milky from the separation of silver chloride.
This condition of eupersaturation seems less liable to occur when lead chloride is
present in the brine together with silver chloride. It thus becomes evident that when
lead and silver chlorides are together present they may be taken up together and held
in solution by boiling or hot brine, and the liquid being decanted off and cooled will
deposit most of the lead and silver together as chlorides. The supernatant liquid
being now drawn off may be made to take up a fresh portion of lead chloride or
lead and silver chlorides by boiling or heating it strongly in contact with a further
portion of these salts, and may be again decanted into the same cooling vessel as
before. On being again cooled it deposits its new charge of lead, or lead and silver
chlorides, with consequent regeneration of its solvent powers. Thus with one and
the same batch of brine any reasonable quantity of lead, and silver chlorides, may
be carried over by successive treatment, and be deposited in the cooling vessel by
again
A
or lead
A

page_text: alternate heatings, decantations, and coolings, the solvent powers of the brine being
thus able to be regenerated by what is practically nothing more than mere cooling
any reasonable number of times. It is this carrying power of brine for lead, or
lead and silver chloride, which I have been able to utilize in my improved process
of separating metals in ores.
It should be observed in accordance with what has been above stated that the
silver does not precipitate entirely out of the brine, together with the lead, and
where present in small proportion, more or less or even the whole of the silver
may be retained in solution by the cooled brine; traces also of this metal will
generally be found in the solution of the chlorides dissolved by the acid treatment.
The best mode of extracting this silver, whether from the brine or the soluble
metallic chlorides taken up by the hydrochloric acid (should that acid have been
employed), is to immerse in the liquid some metallic lead. The spongy lead
formed by reducing lead chloride with zinc answers very well; or some of the
lead contained in the liquids themselves may be reduced by zinc, and left to digest
in or boiled in the liquid, when this lead will be observed to take on a peculiar
grey tint due to precipitation of silver, and will gradually collect all traces of
silver from the solutions.
It should also be observed that if metallic lead be digested with the hot brine
before the lead chlorides has crystallised at all, it will collect all the silver in a
similar manner, some of the lead passing into solution in replacement of silver
precipitated. By collecting all the silver by means of a small quantity of lead,
highly argentiferous lead can be produced, fit to go direct to the cupel without any
intermediate process.
and
I specially specify the employment of lead as being the most suitable and
convenient in these circumstances, and offering special facilities for the subsequent
separation and refining of the silver ▲ as being for this reason far superior to iron,
copper, or any other of the metals, the employment of which may have been
proposed for collecting silver from its solutions. In view of this fact of some of
the silver remaining in the brine, together with what lead is still retained in
solution after cooling, the advantage accruing from the employment of as retricted
a quantity of brine as possible and the using of the same brine over and over again
as a carrier and depositor of the lead, or lead and silver, will be obvious, for by this
means the least possible quantity of silver is retained by the brine; on the other
hand, if desirable, by so graduating the quantity of the brine as to make it
sufficient the whole of the silver in solution, this metal may be thrown down
and collected by boiling or digesting spongy or other metallic lead in the brine,
and the usually employed processes of desilverizing, or rather what should be
called concentrating the silver in the lead previous to cupellation, may be done
away with, the silver being thus once obtainable in a sufficiently concentrated
form for immediate cuppeliation.
to retain
at
.
I arrange the tubs in which the ore is to be attacked in such a manner as to be
able conveniently to decant the liquids from any one of these to any other, and I
perform in succession,―
1st. The drawing off of the saturated acid solutions of the soluble bases into a
reservoir.
2nd. The additions of fresh acid to the partially attacked ore, from which the
above saturated solutions have been decanted; and,
3rd. The subsequent extraction of the lead and silver from the gangue with brine
in such order that while the saturated or neutralized chloride of zinc or copper is
drawn off at one end of the series, fresh acid is poured on to the partially extracted
ore at the other end, fresh acid not on the one hand being poured on to fresh ore,
nor any solution on the other hand being decanted off into the reservoir until it has

page_text: passed over fresh ore. It will be scon that my object is to obtain more perfectly
neutralized solutions of the bases soluble in acids.
meld
A
Where hydrochloric is employed, this form of treamtent is specially necessary
in order to prevent the lead or lead and silver chlorides from being retained in
solution and carried over in large quantity by the solution of zinc and other soluble
bases, it being desirable to retain the lead and silver as far as possible with the
gangue in order to be extracted afterwards by the brine.
I shall now, for better explanation, proceed to illustrate my process as applied
to a treatment of Anglesca bluestone under my acid chlorination process, Patent
dated Fifteenth February, One thousand eight hundred and seventy seven
(No. 633). It however must be understood that I also intend my Invention to be
applicable to all cases where it is intended to separate lead, or lead and silver, from
either or any of the above named metals, as, for instance, when using my sulpha-
tation and brine process, Patent dated July Twenty third, One thousand eight
hundred and seventy seven (No. 2807). For the better elucidation of my present
improved process, I will now describe its working with an example of its practical
application with the arrangement of apparatus which I have found most beneficial.
For the sake of simplicity I will suppose in my description that only two
attacking tubs are employed in series, as illustrated in Sheet One of the annexed
Drawings, though the same principle can be applied to any greater number in
series 3, 4, 5, or more, as illustrated in Sheets 2 and 3 of the Drawings
The ore
A and B are two attacking or dissolving tubs, they may be round, and heated
by means of a steam coil passing round the interior about 6 inches from the
bottom. If from a quarter to half a ton of calcined bluestone is to be treated at
a time, each tub may be, say, five feet diameter at the bottom and four feet six at
the top, by four fect to four feet six inches in depth. They should be placed on a
raised platform higher than the other tubs now to be described, and conveniently
fitted with tops or syphons for drawing off the liquors when required.
is agitated very conveniently by a steam jet blown into the liquid so soon as
it has been brought to boil by the steam coil, but any other form of agitation
may be employed. C is a large tank placed just lower than the bottoms
of A and B, and is to contain brine. It is furnished with a cooling coil
passing round its upper part, or some other arrangement of pipes through which
a stream of cold water can be passed for cooling purposes; but other forms of
refrigeration may be employed; D is another tank, which is empty, and may
conveniently be likewise furnished with a refrigerating apparatus, and may stand
on the same level as C. This tank or reservoir D serves to receive the acid
solution of the soluble bases which the ore may contain. Some pounded ore,
calcined or not as the case may require, is placed in A. This is wetted with a
little water to prevent its caking together on adding the acid and the quantity of
acid, which may be sufficient to combine with all the soluble and attackable bases
the ore may contain is then poured over it. If bydrochloric acid be used, acid of
a strength corresponding to 15° Twaddell answers well.
to be
A
The quantity of acid employed will vary with the composition of each kind
of ore.
The solution is then heated to about boiling point, and so soon as the intensity
of the reaction begins to diminish notably, the liquor, still very acid, is to bo drawn
over into B, in which has been placed a like quantity of pounded ore wetted with
water as above. Here the liquor is again boiled and stirred. This causes the acid
to become as nearly saturated as possible, by taking up a further quantity of the
more soluble metallic oxides contained in this new batch of ore. Having then
thus passed through these two tubs in succession and over two lots of ore, the
liquor after being let to settle is decanted into the reservoir D. Meanwhile a now
portion of acid is poured on to the ore remaining in A, and boiled, and decanted
into B as before. By this means all the soluble bases are taken out of the oro
in A. Some brine, say about the same quantity as that of the acid used, is to be

page_text: pumped from the tank C into A and brought to boil and agitated. This will
generally suffice to take up all the lead and silver at once. It is allowed to settle
as clear as possible, keeping the tub A covered to prevent cooling, and is then
drawn off back into C. If necessary, a further charge of brine is to be passed over
the residue in A, when all the lead and silver will almost inevitably have been
taken up and carried over into C.
from
The gangue is now removed. A and a supply of fresh ore is introduced and
wetted with water as before. The ore in B is now treated with a charge of acid
and boiled and this decanted into A, and thence as before into D, the residue in B
being now extracted with brine from C as before, and the gangue removed and a fresh
charge of ore introduced, and so on continuously. From this description it will be
understood how my improved process of separating metals by an alternately
conducted methodical treatment may be carried out in practice. The liquors in D
contain but little lead or silver, and as they cool, these for the most part crystallise
out, and may be removed and added to the brine in C, while in C the lead and
silver accumulated from the successive treatments, and these separate out in a
crystalline form as chlorides. So soon as a sufficient quantity of the chlorides of
lead and silver have accumulated in C, the brine may be drawn off, and into the
muddy deposit representing the crystalline chlorides lumps of zinc are to be
plunged, and these reduce the metals which may then be collected and melted into
ingots, as described in the Specification of my said former Patents: The chloride
of zinc produced may be added to that in reservoir D.
collectivo
A
In cases where we have to treat lead ores, or lead and silver ores, or residues, or
natural products containing these as sulphates or chlorides already formed (as for
instance, in treating fluo stuff from lead works, silver and lead ores, which have
been previously sulphated or chlorinated, residues from which soluble zinc, nickel,
or other chlorides or sulphates have been extracted by previous lixiviation), of
course the operation becomes so far simplified. The reservoir D) may be done
away with since the acid attack becomes no longer necessary, and only one heating
tub need be used to attack the material with brine. It suffices then in this case
to use the brine reservoir and one attacking tub. The brine acts better if it be
slightly acidulated; the same principle however of using brine as a carrier here
holds good. If the chlorination or sulphatation is incomplete, it should however bo
completed with more acid.
only
A
The lead or lead and silver may now be taken up, drawn over, and deposited by
brine, using over and over again the same brine for the carrying of successive
charges of theso metals, which are deposited as chlorides by cooling and then
reducing them to the inetallic state in the same way as above described in cases
where my complete process is employed. It will be seen then that the process in
this case thus remains virtually the same, the solo difference being the suppression
of the acid treatment where not requisite, and the use of the brine as a carrier for
the lead and silver continues as before described. Solutions of most of the other
soluble alkaline, earthy, and metallic chlorides might be substituted for the brine
in this process, but they are for the most part costly, and as their differential
* powers for lead, and for lead with silver when hot and cold are generally
less those of brine, their carrying powers are less complete. The latter then
is specially recommended as the carrying agent.
solvent
than
▲
moro
The following may be considered as a summary of the advantages accruing from
the above described mode of treatment.
(1.) Better saturation of the acid by the soluble constituents of the ore and
consequent economy of acid.
(2.) More complete attack of the ore and consequent better extraction of the
metals it contains.
(3.) More complete separation of the zinc and copper from the lead and silver.

page_text: down.
The copper is ootamed in a solution, from which it can be more easily thrown
(5.) With but a small quantity of brine, a large quantity of lead and silver
may be carried over by these systematic successive heatings, decantations, and
coolings.
(6.) The lead and silver are obtained together in the best available form, and
very pure.
(7.) The quantity of zinc used up in the reduction of the cblorides to the metallic
state is diminished to a minimum.
(8.) Greater rapidity of working is obtained, and the same amount of work is done
with the least possible quantity of plant.
(9.) The metallic sponge of lead remaining after the reduction of the chloride of
lead mud subsequent to decanting the supernatant brine is obtained in a more
dense coherent form, allowing thus of being more easily washed from any adherent
gangue than if it were precipitated from a larger quantity of brine.
The proportions and form of apparatus herein described, may, as will be apparent
to a person conversant with processes of a like naturo, be easily varied as in
practice may be found desirable.
It will be seen that this Invention divides itself naturally into three heads, viz :-
1st. The application of the methodic alternate and continuous treatment.
2nd. The obtaining well neutralized solutions of the more soluble bases, whereby
the least possible quantities of lead or silver are carried over when the acid
solution is decanted. 3rd. The utilization of the extraordinary differences of
solubility in hot and cold brine respectively, of chloride of lead, or of the mixed
chlorides of lead and silver, thus enabling the brine to be employed as a carrier for
these metals.
Having described the nature of my 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 separation of metals such as silver, lead, zinc, and copper, in ores
containing them by treating the ores with acid and brine, substantially as
herein before described.
the
2nd. I claim in the treatment of ores containing lead and silvor, the separation
of silver and lead by means of the hot brine treatment and the cooling thereof,
substantially as herein described.
A
3rd. I claim the mode of employing brine as a carrier and depositor of silver
and lead by means of alternate heatings, decantations, and coolings, substantiially
as herein described.
4th. I claim the use in my process of treating mineral ores or metallic mixtures
of apparatus arranged and employed, substantially in the manner and for the
purposes herein described.
5th. I claim that part of my improved process, herein referred to, which relates
to tho causing the lead or lead and silver to remain almost entirely in the
attacking vessels, and not to be carried over with the acid liquors employed, the
said acid liquors being carefully neutralized before decanting them finally into the
tank which receives them, thus retaining the lead or lead and silver with the
ganguo ready for extraction by the brine, substantially as herein described.
6th. The employment of metallic lead as a precipitant for the silver in the brine,
or the acid solution of the soluble chlorides, essentially in the manner above
described.
In witness whereof, I, the said Farnham Maxwell Lyte, have hereunto set my
hand and seal, this Second day of February, in the year of our Lord One
thousand night bundna
F. MAXWELL LYTE. (LS)

page_text: I hereby grant my fiat, giving leave to the above named Farnham Maxwell Lyte,
to file in the Office of the Commissioners of Patents 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 advertized in the
London Gazette, the Commissioners of Patents' Journal, the Times, the Standard,
the Daily Telegraph, and the Newcastle Daily Journal

page_text: LETTERS PATENT to Farnham Maxwell Lyte, of the Scientific Club, Savile
Row, in the County of Middlesex, for the Invention of "AN IMPROVED MODE
OF OPERATING IN THE SEPARATION OF ALL OR EITHER OF THE METALS, LEAD,
ZINC, SILVER, OR COPPER IN MIXED ORES OR METALLIC MIXTURES, BY MEANS
OF ACIDS, BRINE, AND CERTAIN OTHER REAGENTS."
Scaled the 25th March 1879, and dated the 22nd January 1879.
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell Lyte at
the Office of the Commissioners of Patents on the 22nd January 1879.
FARNHAM MAXWELL LYTE, of the Scientific Club, Savile Row, in the County of
Middlesex. "AN IMPROVED MODE OF OPERATING IN THE SEPARATION OF ALL OR
EITHER OF THE METALS, LEAD, ZINC, SILVER, OR COPPER IN MIXED ORES OR
METALLIC MIXTURES, BY MEANS OF ACIDS, Brine, and cerTAIN OTHER REAGENTS."
My Invention relates to the application of a methodical, alternate, and continuous
system of treatment of ores or metallic compounds by means of acid, wherein by a
convenient disposition of the vessels and a special order of decantations the same
acid is caused to pass successively over a series of two or more batches of ore, thus
becoming completely saturated with the zinc and copper the said ore may contain,
and becoming consequently as neutral as possible. Thus while the utmost possible
economy of acid is obtained the least possible quantities of lead or iron are carried
over in solution with the zine or copper (the said lead and silver and most of the
iron remaining behind with the gangue), so that the lead and silver which have
become converted into chlorides can be readily taken up with boiling brine and
precipitated together as usual with metallic zinc.
Q
I so arrange the attacking vats in which the ore is treated with the acid as to be
able to decant the liquids from oue of these to any other, and I so ordain the order
of the decantations, the withdrawal of the saturated liquors, and the additions of
fresh acid, that each time a batch of saturated zinc or zinc and copper chlorides are
withdrawn from one end of the series a fresh batch of acid can be added at the
other end.
I will proceed to explain the operation by illustrating the principle as applied
to the treatment of Anglesea bluestone according to the acid chlorination process,
patented by me, dated February 15th, 1877, No. 633; although I intend the principle

page_text: to be generally applicable to all cases where lead or silver have to be separated
from zine or copper by acids. I will presume for greater simplicity that only two
attacking tubs are used in series, though following the same principle any number,
say, 3, 4, or 5 might be employed.
Let A and B be two attacking tubs properly fitted with heating apparatus and
means for decanting. A is charged with the requisite quantity of ore. Over this
is to be poured the quantity of acid just requisite for taking up and entering into
combination with all the attackable constituents of the ore. This quantity will of
course vary with the composition of the said ore. So soon as the reaction in A
begins to notably diminish, the liquor is to be decanted off into B in which another
like quantity of ore has been placed. Here the acid becomes fully saturated at
once with the zinc, copper, and other soluble matters in this fresh batch of ore, and
by being passed succossively over both batches of ore is rendered as neutral as
possible. Part of the sesquioxide of iron also which the ore may have contained
and which may have passed into solution as sesqui-chloride becomes here precipitated
as hydrated sesquioxide.
After agitation and boiling as usual the liquid is allowed to settle. Meanwhile n
batch of fresh acid is poured over the residue in A and being again boiled and
agitated completes the attack of the ore, and while it takes up the last traces of
zinc and copper, chloridises completely the last traces of lead and silver. The clear
liquid should now be decanted from B into a tank C, and the still strongly acid
liquor from A is then decanted into B, and being boiled up and agitated completes
the attack of the ore in B. A store of brine may be kept in a tank D, and of this
a sufficient quantity, say, 15 or 20 parts for each one of lead chloride contained in
the residue in A as calculated from the quantity of lead in the ore treated is drawn
over cold into A, and heated to boiling when it will take up all the lead chloride
and being decanted back into D or into any other suitable vessel carries with it
the lead, leaving only the gangue and the greater part of the iron sesquioxide in A;
this exhausted residue may then be thrown away. A batch of fresh ore is now to
be placed in A and the hot liquor from B decanted onto it when, as in the former
case, it becomes saturated with the more soluble metals, and when settled this
liquid may be decanted off into C or any other receiving vessel. A is now treated
with a portion of fresh acid and this again decanted into B and the residue in A
extracted with brine as before, and so on continually by the same methodic alter-
nating system as long as may be required. Some of the lead chloride passes over
all the same with the zinc and copper chlorides, but this separates out almost
entirely as the liquor in C cools, and may be collected, drained, and added to the
chloride in the brine. As the brine cools it deposits most of its lead and silver
chlorides, and may be used over and over again to take up more successively from
each fresh batch of ore when it is decanted over and boiled up and agitated with
it, acting thus as a mere carrier of lead chloride which accumulates and becomes
deposited in the tank C.
This treatment it will be observed is somewhat similar in principle to that
followed for the lixiviation of black ash and many other industrial operations.
It will be observable that by this means we obtain, 1st, better saturation and
consequent economy of acid; 2nd, more complete solution and consequently
better extraction of the metals from the ore; 3rd, more perfect separation of tho
zinc and copper on the one hand from the lead and silver on the other, and of the
gangue and the largest part of the iron from all these said metals; 4th, the more
convenient precipitation of the copper apart and in a condition of comparative s
freedom from lead or silver; 5th, that the lead and silver are obtainable together
also in a purer condition; 6th, that the economy of the hard spelter or zinc used
in precipitating the metals is considerable owing to the more neutral condition of
the solutions; also that there is considerable economy of salt and acid with this
mode of working; 7th, that the operations are more rapidly conducted and that
the number of vessels employed may be reduced to a minimum.

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 July 1879.
FARNHAM MAXWELL LYTE, of the Sientific Club, Savile Row, in the County of
Middlesex. "AN IMPROVED MODE OF OPERATING IN THE SEPARATION OF ALL OR
EITHER OF THE METALS, LEAD, ZINC, SILVER, OR COPPER IN MIXED ORES OR
METALLIC MIXTURES, BY MEANS OF ACIDS, BRINE, AND CERTAIN OTHER REAGENTS."
This Invention relates in part to improvements founded upon those described in
the Specifications of my former Letters Patent, dated respectively the Fifteenth
February, One thousand eight hundred and seventy seven, and the Twenty third
July, One thousand eight hundred and seventy seven.
It relates, firstly, to a process of continuous methodical and alternate treatment
as applied to minerals and certain metalliferous compounds, whereby metals therein
contained, such as lead, zinc, silver, or copper, may be ultimately separated there-
from, the ultimate separation being in some cases preceded by an intermediato
separation of mixtures of one or more of these metals, as for instance, where ores
containing antimony are treated, and lead and silver mixed with antimony are
separated intermediately, and by an ultimate process of cooling, lead and silver are
separated from the solution wherein antimony is retained, as is hereinafter more
fully described; 2ndly, this Invention relates to the application in the special
manner about to be described of acids followed by brine, and certain other
reagents.
In carrying my improved process into practical operation, I employ apparatus
consisting of a set of vessels suitably disposed, so as to be able to effect a series of
decantations in regular and successive order, and in such a manner that each lot of
acid may be made on the one hand to pass successively over two or more lots of
ore, the result of which is that the said acid becomes more completely saturated
and neutralized by the soluble and attackable constituents of the ore, while on the
other hand each lot of ore receives treatment by at least two acid solutions, that is
to say, first, when raw and more easily attacked it is treated by a partially
saturated acid which has been already used in a previous attack; and secondly,
when having lost part of its soluble constituents it has become less easily
attackable, it is treated a second time but with fresh acid, which has not yet acted
on any previous lot of ore. The extraction of the metals is thus made more complete.
The insoluble sulphate or chloride of lead remaining with the gangue and retaining
the silver which the ore may contain is successively extracted by one or more
boilings or heatings in strong brine, which is made completely to take up and carry
over into another vessel suitably disposed all the dissolved lead and silver, and
deposit them there as crystalline chlorides on cooling.
In some cases the brine may be with advantage acidulated. About one or two
per cent. of acid relatively to the quantity of brine will usually be found sufficient.
If any antimony or bismuth are contained in the ore, these are either carried off
by the acid treatinent or become more or less dissolved together with the silver and
lead in the hot brine, and are carried over with the lead and silver, but the autimony
and bismuth do not, like the silver and lead, separate on cooling, but are retained in
the brine. By this mode of treatment while I obtain a considerable economy in
the quantity of acid employed, I also (which is very important) carry over with the
chlorides of zinc and other bases forming soluable chlorides or sulphates, the lenst
possible proportion of lead or silver, these being only slightly soluble in well
neutralised solution of zinc and other bases (which are conventionally but perhaps
strictly speaking rather improperly distinguished from the alkalies or the alkaline
earths as metallic bases), and remaining consequently with the gangue in the
attacking vessel. These salts of lead and silver when treated with hot or boiling brine
dissolve therein as chlorides, no matter whether they may be originally present as
sulphates or chlorides. It here becomes necessary to make a few remarks relating
to the solubility of silver and lead chlorides in brine, and the mode of separating

page_text: them from antimony or bismuth when those metals or either of them may be
present.
I have ascertained that lead chloride is soluble in boiling saturated solution of
sodium chloride (brine) to the extent of about 1.35 parts (= 1 part of metallic
lead) to twenty five of boiling brine, whereas on cooling down to ordinary tein-
peratures most of the chloride of lead crystallises out, until no more than about
one of metallic lead to eight hundred or one thousand of brine remains in
solution. Silver on the other hand is soluble in the same liquid to the extent
of about 0-75 parts of silver, under the form of silver chloride to one thousand
of brine at 10° to 12° C., about 0.90 of silver to one thousand of brine at
25° to 26° C., and about double that quantity at a boiling temperature. The
presence of lead chloride in the brine seems rather to increase this rato of
solubility of silver as silver chloride. The solution of silver chloride in brine
appears to be peculiarly liable to what is termed supersaturation, so much so that
it will often be found that brine saturated hot with silver chloride will remain
clear on cooling until some determining cause, such as the addition of an atom of
solid silver chloride intervenes, when immediately the whole liquid will turn milky
from the separation of silver chloride. This condition of supersaturation seems less
liable to occur when lead chloride is present in the brine, together with silver
"chloride. It thus becomes evident that when load and silver chlorides are together
present, they may be taken up together and held in solution by boiling or hot
brine, and the liquid being decanted off and cooled will deposit most of the lead and
silver together as chlorides. The supernatant liquid being now drawn off may be
made again to take up a fresh portion of lead chloride, or lead and silver chlorides
by boiling or heating it strongly in contact with a further portion of these salts, and
may be again decanted into the same cooling vessel as before. On being again
cooled it deposits its new charge of lead or lead and silver chlorides with consequent
regeneration of its solvent powers. Thus, with one and the same batch of brine
any reasonable quantity of lead or lead and silver chlorides may be carried over by
successive treatment, and be deposited in the cooling vessel by alternate heatings,
decantations, and coolings; the solvent powers of the brine being thus able to be
regenerated by what is practically nothing more than mere cooling and reasonable
number of times. It is this carrying power of brine for lead or lead and silver
chloride which I have been able to utilise in my improved process of separating
metals in ores.
Should antimony, bismuth, or other metals soluble in brine be present, they will
be found according to the forms in which they existed to have been more or less
taken up by the brine, and be transported with the lead and silver, but they will
still be retained in the brine solution, when on cooling it precipitates lead and silver
from the solution, in which however a certain portion of those last named metals
may be still retained. The presence of the antimony, bismuth, or other soluble
metals thus retained in solution does not appear materially to affect the solvent and
carrying powers of the brine for fresh charges of silver or lead chlorides. I utilise
these reactions then for separating lead and silver from other metals, for example,
in the treatment of lead, or lead and silver ores containing antimony. The crystalline
wet deposit of lead and silver chloride is washed with a little fresh cold brine if
requisite, and then may be reduced with zinc, when it will be found to yield soft
lead mixed with silver, but free from antimony, bismuth, or any other metals.
It should be observed in accordance with what has been above stated, that the
silver does not precipitate entirely out of the brine together with the lead, and
where present in small proportion, more or less, or even the whole of the silver may
be retained in solution by the cooled brine; traces also of this metal will generally
be found in the solution of the chlorides dissolved by the acid treatment. The best
mode of extracting this silver, whether from the brine or the soluble metallic
chlorides taken up by the hydrochloric acid (should that acid have been employed),
is to immerse in the liquid some metallic lead. The spongy lead formed by reducing
lead chloride with zinc answers very well, or some of the lead contained in the

page_text: liquids themselves may be reduced by zinc, and left to
liquid, when this lead will be observed to take on
precipitation of silver, and will gradually collect all
solutions.
digest in or boiled in the
peculiar grey tint due to
traces of silver from the
It should also be observed that if metallic lead be digested with the hot brine
before the lead chloride has crystallised at all, it will collect all the silver in a
similar manner, some of the lead passing into solution in replacement of silver
precipitated. By collecting all the silver by means of a small quantity of lead,
highly argentiferous lead can be produced, fit to go direct to the cupel without any
intermediate process.
I specially specify the employment of lead as being the most suitable and conve-
nient in these circumstances, and offering special facilities for the subsequent
separation and refining of the silver, and as being for this reason far superior to
iron, copper, or any other of the metals, the employment of which may have been
proposed for collecting silver from its solutions. In view of this fact of some of
the silver remaining in the brine, together with what lead is still retained in solu-
tion after cooling, the advantage accruing from the employment of as restricted a
quantity of brine as possible, and the using of the same brine over and over again
as a carrier and depositor of the lead, or lead and silver, will be obvious, for by
this means the least possible quantity of silver is retained by the brine. On the
other hand, if desirable, by so graduating the quantity of the brine as to make it
sufficient to retain the whole of the silver in solution, this metal may be thrown
down and collected by boiling or digesting spongy or other notallic lead in the
brine, and the usually employed processes of desilverizing, or rather what should be
called concentrating the silver in the lead previous to cupellation may be done away
with, the silver being thus at onco obtainable in a sufficiently concentrated form for
immediate cupellation.
I arrange the tubs in which the ore is to be attacked in such a manner as to bo
able conveniently to decant the liquids from any one of these to any other, and I
perform in succession,-
1st. The drawing off of the saturated acid solutions of the soluble bases into a
reservoir.
2nd. The additions of fresh acid to the partially attacked ore, from which the
above saturated solutions have been decanted, and
3rd. The subsequent extraction of the lead and silver from the gangue with brine,
in such order that while the saturated or neutralized chloride of zinc or copper is
drawn off at one end of the series, fresh acid is poured on to the partially extracted
ore at the other end, fresh acid not on the one hand being poured on to fresh ore,
nor any solution on the other band being decanted off into the reservoir until it has
passed over fresh ore. It will be seen that my object is to obtain more perfectly
neutralized solutions of the bases soluble in acids.
Where hydrochloric acid is employed, this form of treatment is specially necessary
in order to prevent the lead or lead and silver chlorides from being retained in
solution, and carried over in large quantity by the solution of zinc and other soluble
bases, it being desirable to retain the lead and silver as far as possible with the
gangue, in order to be extracted afterwards by the brine.
I shall now, for better explanation, proceed to illustrate my process as applied to
a treatment of Anglesea bluestone, under my acid chlorination process Patent,
dated Fifth February, One thousand eight hundred and seventy seven (No. 633).
It however must be understood that I also intend my Invention to be applicable
to all cases where it is intended to separate lead or lead and silver from either or
any of the above named metals, as for instance, when using my sulphatation and
brine process Patent, dated July Twenty third, One thousand eight hundred and
seventy seven (No. 2807). For the better elucidation of my present improved process,
I will now describe its working with an example of its practical application with
the arrangement of apparatus which I have found most beneficial. For the sake of
simplicity I will suppose in my description that only two attacking tubes are.

page_text: employed in series, as illustrated in Sheet 1 of the annexed Drawings, though the
same principle can be applied to any greater number in series 3, 4, 5, or more, as
illustrated in Sheets 2 and 3 of the Drawings.
A and B are two attacking or dissolving tubs, they may be round and heated by
means of a steam coil passing round the interior, about 6 inches from the bottom.
If from a quarter to half a ton of calcined bluestone is to be heated at a time, each
tub may be, say, 5 feet diameter at the bottom, and 4 feet 6 at the top, by 4 feet to
4 feet 6 inches in depth. They should be placed on a raised platform higher than
the other tubs now to bo described, and conveniently fitted with taps or syphons for
drawing off the liquors when required. The ore is agitated very conveniently by a
steam jet blown into the liquid so soon as it has been brought to boil by the steam
coil, but any other form of agitation may be employed. C is a largo tank placed
just lower than the bottoms of A and B, and is to contain brine. It is furnished
with a cooling coil passing round its upper part, or some other arrangement of pipes
through which a stream of cold water can be passed for cooling purposes, but other
forms of refrigeration may be employed. D is another tank which is empty, and
may conveniently be likewise furnished with a refrigerating apparatus, and may
stand on the same level as C. This tank or reservoir D serves to receive the acid
solution of the soluble bases which the ore may contain. Some pounded ore,
calcined or not, as the case may require, is placed in A; this is wetted with a little
water to prevent its caking together on adding the acid, and the quantity of acid
which may be sufficient to combine with all the soluble and attackable bases the
ore may contain is then poured over it. If hydrochloric acid be used, acid of a
strength corresponding to 15° Twaddell answers well.
The quantity of acid to be employed will vary with the composition of each kind
of ore.
The solution is then heated to about boiling point, and so soon as the intensity of
the reaction begins to diminish notably, the liquor still very acid, is to be drawn
over into B, in which has been placed a like quantity of pounded ore, wetted with
water as above. Here the liquor is again boiled and stirred. This causes the acid
to become as nearly saturated as possible by taking up a further quantity of the
more soluble metallic oxides contained in this new batch of ore. Having then thus
passed through these two tubs in succession, and over two lots of ore, the liquor
after being let to settle is decanted into the reservoir D. Meanwhile a new portion
of acid is poured on to the ore remaining in A, and boiled and decanted into B as
before. By this means, all the soluble bases are taken out of the ore in A. Some
brine, say, about the same quantity as that of the acid used, is to be pumped from
the tank C into A, and brought to boil and agitated. This will generally suffice to
take up all the lead and silver at once. It is allowed to settle as clear as possiblo,
keeping the tub A covered to prevent cooling, and is then drawn off back into C.
If necessary, a further charge of brine is to be passed over the residues in A, when
all the lead and silver will almost inevitably have been taken up mixed with
antimony or bismuth, if either of those metals be present, and carried over into C.
The gangue is now removed from A, and a supply of fresh ore is introduced and
wetted with water as before. The ore in B is now treated with a charge of acid
and boiled, and this decanted into A, and thence as before into D, the residue in B
being now extracted with brine from C as before, and the gangue removed, and a
fresh charge of ore introduced, and so on continuously. From this description it
will be understood how my improved process of separating metals by an alternately
conducted methodical treatment may be carried out in practice. The liquors in Ď
contain but little lead or silver; and as they cool, these for the most part crystallizo
out, and may be removed and added to the brine in C, while in the lead and
silver accumulate from the collective successive treatments, and these separato out in
a crystalline form as chlorides. So soon as a sufficient quantity of the chlorides of
lead and silver have accumulated in C, the brine may be drawn off and into the
muddy deposit representing the crystalline chlorides, lumps of zinc are to be
plunged, and these reduce the metals, which may then be collected and melted into

page_text: ingots as described in the Specification of my said former Patents. The chloride of
zinc produced may be added to that in reservoir D.
When we have to deal with an ore containing antimony or bismuth mixed with
lead, or lead and silver, the antimony or bismuth is dissolved and taken up more or
less completely by the acid solutions, a small part of these will however remain in
the brine. If the ore has been treated by what I term my sulphatation Patent,
No. 2807, dated July 23rd 1877, much antimony and bismuth will go into the
brine. This however, as above stated, appears not to interfere with the carrying
powers of the brine, in which these metals are retained when the liquid is cooled,
while the lead and silver chlorides are deposited free from antimony. My improved
process, as is obvious, then affords an excellent means for the separation of antimony
and bismuth from lead, or lead and silver.
In cases where we have to treat lead ores, or lead and silver ores, or residues, or
natural products containing these as sulphates or chlorides already formed (as for
instance in treating flue stuff from lead works, antimonial silver and lead ores
which have been previously sulphated or chlorinated, residues from which soluble
zinc, nickel, or other chlorides or sulphates have been extracted by previous
lixiviation) of course the operation becomes so far simplified. The reservoir D may
be done away with since the acid attack becomes no longer necessary, and only one
heating tub need be used to attack the material with brine. It suffices then in this
case to use only the brine reservoir and one attacking tub. The brine acts better if
it be slightly acidulated; the same principle however of using brine as a carrier hero
holds good. If the chlorination or sulphatation is incomplete it should however be
completed with more acid.
The lead, or lead and silver may now be taken up, drawn over, and deposited
by brine, using over and over again the same brine for the carrying of successive
charges of these metals which are deposited as chlorides by cooling and then
reducing them to the metallic state in the same way as above described in cases
where my complete process is employed. It will be seen then that the process
in this case thus remains virtually the same, the sole difference being the sup-
pression of the acid treatment where not requisite, and the use of the brine as a
carrier for the lead and silver continues as before described. Solutions of most of
the other soluble alkaline, earthy, and metallic chlorides might be substituted
for the brine in this process, but they are for the most part more costly, and as their
differential solvent powers for lead and for lead with silver when hot and cold are
generally less than those of brine their carrying powers are less complete. The
latter then is specially recommended as the carrying agent.
The following may be considered as a summary of the advantages accruing from
the above described mode of treatment.
(1.) Better saturation of the acid by the soluble constituents of the ore, and
consequent economy of acid.
(2.) More complete attack of the ore, and consequent better extraction of the
metals it contains.
(3.) More complete separation of the zinc and copper from the lead and silver.
(4.) The copper is obtained in a solution, from which it can be more easily thrown
down.
(5.) With but a small quantity of brine a large quantity of lead and silver
may be carried over by these systematic successive heatings, decantations, and
coolings.
(6.) The lead and silver are obtained together in the best available form and very
pure.
(7.) The antimony may be eliminated.
(8.) The quantity of zinc used up in the reduction of the chlorides to the metallic
state is diminished to a minimum.
(9.) Greater rapidity of working is obtained and the same amount of work is
done with the least possible quantity of plant.
(10.) The metallic sponge of lead remaining after the reduction of the chloride

page_text: of lead mud subsequent to decanting the supernatant brine is obtained in a more
denso coherent form, allowing thus of being more easily washed from any traces of
precipitated antimony, as well as from any adherent gangue, than if it were
precipitated from a larger quantity of brine.
The proportions and form of apparatus herein descrihed may, as will be apparent
to a person conversant with processes of a like nature, be easily varied as in practice
may be found desirable.
It will be seen that this Invention divides itself naturally into four heads, viz.:-
1st. The application of the methodic, alternate, and continuous treatment.
2nd. The obtaining well neutralised solutions of the more soluble bases, whereby
the least possible quantities of lead or silver are carried over when the acid solution
is decanted. 3rd. The utilization of the extraordinary differences of solubility in
hot and cold brine respectively of chloride of lead or of the mixed chlorides of lead
and silver, thus enabling the brine to be employed as a carrier for these metals.
4th. The utilization of the fact that when lead and silver are dissolved in hot or
boiling brine, together with antimony, bismuth, or other metals as chlorides, the
lead or lead and silver alone separate out on cooling, leaving antimony, bismuth,
and the other metals in solution.
Having described the nature of my 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 separation of metals, such as silver, lead, zinc, and copper in ores con-
taining them by treating the ores with acid and brine, substantially as hereinbefore
described.
2nd. I claim in the treatment of ores containing antimony or bismuth mixed
with lead or lead and silver, the separation of the silver and lead by means
of the hot brine treatment, and the cooling thereof, substantially as herein
described.
3rd. I claim the mode of employing brino as a carrier and depositor of silver and
lend by means of alternate heatings, decantations, and coolings, substantially as
herein described.
4th. I claim the use in my process of treating mineral ores or metallic mixtures
of apparatus arranged and employed substantially in the manner and for the
purposes herein described.
5th. I claim that part of my improved process herein referred to which relates to
the causing the lead or lead and silver to remain almost entirely in the attacking
vessels and not to be carried over with the acid liquors employed, the said acid
liquors being carefully neutralized before decanting them finally into the tank
which receives them, thus retaining the lead or lead and silver with the gangue
ready for extraction by the brine, substantially as herein described.
6th. The employment of metallic lead as a precipitant for the silver in the brine
or the acid solution of the soluble chlorides essentially in the manner above
described.
In witness whereof, I, the said Farnham Maxwell Lyte, have hereunto set my
hand and seal, this Fifteenth day of July, in the year of our Lord One
thousand eight hundred and seventy nine.
Witness,
A. M. CLARK,
Patent Agent,
53, Chancery Lane,
London
F. MAXWELL-LYTE. (L.S.)

page_text: C Tank for Temporary use
lo receive Brine from Car-
C'when these are being
cleaned out or when the
Chloride of Lead is being
reduced by zinc.