IMPROVEMENTS IN OBTAIN- ING COPPER, SILVER, TIN, AND SEVERAL OTHER METALS FROM THEIR ORES OR ANY OTHER NATURAL OR ARTIFICIAL COMPOUND CONTAINING ONE OR MORE OF THESE METALS
Year: 1860

page_text: LETTERS PATENT to William Henderson, Chemist, of Alderley Edge, in
the County of Chester, and Jonathan Down, Mine Agent, of Alderley,
in the County of Chester, for the Invention of "IMPROVEMENTS IN OBTAIN-
ING COPPER, SILVER, TIN, AND SEVERAL OTHER METALS FROM THEIR ORES OR
ANY OTHER NATURAL OR ARTIFICIAL COMPOUND CONTAINING ONE OR MORE OF
THESE METALS."
Sealed the 12th April 1861, and dated the 17th October 1860.
PROVISIONAL SPECIFICATION left by the said William Henderson and
Jonathan Down at the Office of the Commissioners of Patents, with
their Petition, on the 17th October 1860.
We, WILLIAM HENDERSON, Chemist, of Alderley Edge, in the County of
Chester, and JONATHAN DOWN, Mine Agent, of Alderley, in the County of
Chester, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN OBTAINING COPPER, SILVER, TIN, AND SEVERAL OTHER METALS FROM THEIR ORES
OR ANY OTHER NATURAL OR ARTIFICIAL COMPOUND CONTAINING ONE OR MORE OF THESE
METALS," to be as follows:-
In working out on, a large scale the details of the Invention, as particularly
described in the Specification for which Her Majesty's Letters Patent,
No. 2900, were granted to the said William Henderson on the 20th
December 1859, we have found that the process therein described (whereby
ores are treated with common salt, their metals converted into chlorides, and
the metallic chlorides thus obtained are sublimed and condensed,) is capable

page_text: of extension to other compounds of the metals, and that other substances
besides common salt can be advantageously used for that purpose.
These improvements consist of, 1st, mixing common salt or any chloride of
an alkali, alkaline earth, carth or metal whose chloride suffers decomposition
at a high heat, with not only the raw or calcined ores, but with reguluses,
matts, precipitate, or any compound or mixture, natural or artificial, whereby
the chloride mixed with or naturally existent in the mixture is decomposed,
and the valuable metals sublimed therefrom at a high heat.
2ndly, the precipitate of copper and silver obtained as described in the
before-mentioned Specification, by precipitating the metals from the solutions
of the chlorides of these metals by iron and galvanized iron is without washing
free from the adhering chlorides of iron, at once dried, and submitted, without
previous admixture with other chlorides, to a high heat, whereby the chloride
of silver is sublimed with small quantities of copper, iron, and other metals
which are condensed, and by this means separated from the great bulk of the
copper, which is converted into oxide, and remains in the furnace.
3rdly, the copper and silver precipitate, when very rich for silver, and a
sufficient quantity of chloride of iron not being present, we assist by an admix-
ture of common salt, or other suitable chloride, with which may be added
silica, sulphates, or sulphurets in small quantities, to assist the decomposition
of the added chlorides.
4thly, we employ the waste product, chloride of iron, as a substitute for
common salt, and if lime, magnesia, or other alkaline earth, alkali, or metal
has been used instead of iron as a precipitant, their resulting chlorides when
duly concentrated.
5thly, when the ores treated or to be treated are very rich in sulphur, and
it is necessary to burn them, either for the purposes of manufacturing sulphuric
acid or simply to get rid of the sulphur, we burn them in properly constructed
fire-places or furnaces under our close calcining furnaces, thereby saving
much fuel.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Henderson and Jonathan Down in the Great Seal
Patent Office on the 17th April 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
1ENDERSON, Chemist, of Alderley Edge, in the County of Chester, and

page_text: JONATHAN DOWN, Miue Agent, of Alderley, in the County of Chester, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of October, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-fourth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said William Henderson and Jonathan Down, Her special licence
that we, the said William Henderson and Jonathan Down, our executors,
administrators, and assigns, or such others as we, the said William Hen-
derson and Jonathan Down, our 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 "IMPROVE-
MENTS IN OBTAINING COPPER, SILVER, TIN, AND SEVERAL OTHER METALS FROM THEIR
ORES OR ANY OTHER NATURAL OR ARTIFICIAL COMPOUND CONTAINING ONE OR MORE OF
THESE METALS," upon the condition (amongst others) that we, the said William
Henderson and Jonathan Down, or one of us, our exccutors or administrators,
by an instrument in writing under our, or their, or one of our or their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said William Henderson and Jonathan
Down, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement thereof, that is to say :-
When treating ores containing copper and silver or either of these metals,
by calcining them with common salt, in close furnaces in connection with
condensers, whereby the chlorides of these metals are volatilized and con-
densed with water; the chlorides are thus obtained in solution, and precipitated
by iron, as particularly described in the Specification of an Invention for which
Her Majesty's Letters Patent, No. 2900, were granted to the said William
Henderson, bearing date the 20th December 1859, we find that the process
can be varied, and for some localities, where common salt and metallic iron,
or either of them, are expensive, other substances can be substituted. Some-
times the waste chloride of iron may be conveniently evaporated by the waste
heat from the calcining furnace in wrought or cast-iron pans, and the dry salt

page_text: (chloride of iron) may then be mixed with fresh ore, with or without any
fresh common salt.
a
The copper may also be precipitated from the chloride of copper solutions
by caustic lime or carbonate of lime at a boiling heat, and the resulting
chloride of calcium, when evaporated to dryness, or as a concentrated liquid,
may be mixed with fresh ores, so as partially or entirely to replace or
substitute the common salt. All the other alkalies or alkaline earths may
also be used in place of lime except magnesia and alumina, magnesia especially
possessing the characteristic when in a state of soluble chloride of parting with
its acid in the process of evaporation to dryness. It cannot, therefore, be
substituted for common salt in the furnace because it parts with its acid too
rapidly. We take advantage of this property when treating a different class
of ores, as presently described. These improvements also relate to the
separation of silver from reguluses, matts, precipitated copper, or any other
natural or artificial compound containing these metals, and from which it is
desirable to separate the silver. The precipitated copper obtained as has been
described generally contains a small quantity of chloride of iron or other
precipitant, and if the silver does not exceed 20 ounces to the ton of precipitate,
no other chlorides need be added, but the dry precipitate may be at once
transferred to the close calcining furnace, and subjected to high calcining
heat, with repeated stirring, until it ceases to smoke. The metallic copper is
by this means converted into oxide, and the whole or nearly the whole of the
silver is sublimed together with a small proportion of the copper, which pass
into the condenser, and are there condensed. When the precipitate is rich in
silver, it will be necessary to add chloride of sodium or other chloride together
with from 3 to 10 per cent. of copper regulus containing silver or rich
sulphuret ore, or any other substance containing sulphur or sulphuric acid or
silica, to assist in decomposing the added chloride. Reguluses or matts of
copper containing silver we treat as follows:-The regulus is reduced to fine
powder, and intimately mixed with from 5 to 25 per cent. of common salt,
chloride of calcium, chloride of iron, or any other chloride of the alkalies,
alkalino earths (except magnesia and alumina), or a mixture of one or more
of these chlorides, and we subject the mixture to a gradually increasing heat
in a close calcining furnace, which communicates with a condensing apparatus.
Instead of using common salt or other suitable chloride, we find it sometimes
convenient to calcine the regulus or other compound rich in copper, so as to
free it as nearly as possible from sulphur, and convert all the metals into
oxides; we then moisten the calcined ore or regulus while still warm with

page_text: muriatic acid, and allow it to dry by its own heat; we then calcine it, driving
off chlorides of copper, iron, silver, and other metals if present, which wo
condense, and afterwards separate, as will be hereafter described. Nearly the
whole of the copper is left in the furnace free or nearly freo from silver. The
charge is withdrawn from the furnace when it ceases to smoke.
Another improvement consists in placing between the tower or wet con-
denser and the furnace a series of flues, or one very long and capacious flue.
In this flue or flues, which should be kept dry, nearly the whole of the
sublimed chlorides deposit, and the perpendicular wet condenser condenses the
last traces, and maintains the draught. We remove the dry powder deposited
in these flues, consisting of chlorides, subchlorides, and oxychlorides of copper,
silver, and other metals, say once a week, and treat with very dilute muriatic
acid, which readily dissolves the copper, iron, arsenic, and other metals, leaving
the silver as insoluble chloride. We obtain the copper from these solutions by
precipitation with iron, lime, or other convenient precipitant, and the chloride
of silver is reduced to the metallic state by zinc and sulphuric acid, or any
other well-known means.
In localities where fuel is expensive, and when the ores to be treated are
rich in sulphur, and it is necessary to burn them either for the purpose of
manufacturing sulphuric acid, or simply to get rid of the sulphur, we burn
them in properly constructed furnaces or fire-places under our close calcining
furnaces. By this means fuel may in some cases be entirely dispensed with,
and in other cases very considerably reduced. The sulphur gases may after-
wards be converted into sulphuric acid by the well known means, or otherwise
utilized; or it may be suffered to escape through the chimney.
Another improvement consists in the use of magnesia to precipitate the
copper from chloride or muriatic acid solutions. The resulting chloride of
magnesium is then concentrated in wrought or cast-iron pans, and finally
evaporated to dryness in a cast-iron pan, domed over, and communicating with
a condensing apparatus. The whole or nearly the whole of the muriatic acid
is readily driven off during the evaporation. The dry salt, if moistened by a
jet of steam and again dried once or twice, may be completely freed from
muriatic acid. By this means the acid may be recovered to redissolve fresh
copper, and the magnesia may be re-used as a precipitant. This process may
be advantageously used to obtain muriatic acid, and keep up the supply.
Chloride of magnesia may be readily obtained in the first instance by dissolving
equivalent weights of Epsom salts and common salt, evaporating and crystal-
lizing out the. sulpbate of soda. The mother liquor is chloride of magnesia.

page_text: The corresponding salts of alumina may be substituted for those of magnesia.
When sulphuric acid or muriatic acid is used to dissolve the copper from
ores containing suboxide of copper, metallic copper, or from sulphuret ores of
copper that have been previously calcined to dissolve the suboxide metallic or
undecomposed sulphuret, we employ a small proportion of nitrate of soda,
potash, or other nitrate readily decomposable by sulphuric or muriatic acid.
The nitrate is mixed with the copper solution, and nitric acid being gradually
liberated, the metallic copper, suboxide, or sulphuret not soluble in the other
acid is immediately dissolved.
We have, for the sake of clearness, confined our description to ores and
products of copper and silver, but we do not confine ourselves to these ores,
but we claim the processes before described for treating ores of tin and other
metals.
And having now described the nature of our said Invention, and in what
manner the same is to be performed, we declare that we claim,-
First, the employment of chlorides of iron, manganese, calcium, sodium,
potassium, and the other alkalies or alkaline earths either singly or in con-
junction for the purposes herein described.
Second, the employment of nitrate of soda, potash, or other nitrate readily
decomposable by sulphuric or muriatic acid, for the purposes herein described.
Third, the methods herein particularly described for obtaining muriatic acid
and magnesia or alumina from their chlorides, and the use of these compounds
for the purposes herein described.
Fourth, the employment of dry flues or condensers, either alone or in
conjunction with a wet tower, for the purposes herein described.
And, lastly, the separation of silver from copper by the several methods
herein described.
In witness whereof, I, the said William Henderson, for myself and on
behalf of the said Jonathan Down, have hereunto set my hand and
seal, this Fifteenth day of April, One thousand eight hundred and
sixty-one.
W. HENDERSON. (L.S.)