IMPROVEMENTS IN THE TREATMENT OF COPPER PRECIPITATE, AND IN THE UTILIZATION OF IMPURITIES CONTAINED THEREIN
Year: 1872

page_text: LETTERS PATENT to James Hawke Dennis, of Liverpool, in the
County of Lancaster, Commission Merchant, for the Invention
of "IMPROVEMENTS IN THE TREATMENT OF COPPER PRECIPITATE, AND IN
THE UTILIZATION OF IMPURITIES CONTAINED THEREIN."
Sealed the 26th November 1872, and dated the 28th May 1872.
at the Oince of the Commissioners OT
the 28th May 1872.
I, JAMES HAWKE DENNIS, of Liverpool, in the County of Lancaster,
Commission Merchant, do hereby declare the nature of my Invention
for "IMPROVEMENTS IN THE TREATMENT OF COPPER PRECIPITATE, AND IN THE
UTILIZATION OF IMPURITIES CONTAINED THEREIN," to be as follows:-
The object of my Invention is to purify commercial copper precipitate
obtained by the wet method of extracting copper from its ores, and to
utilize some of the metallic impurities extracted therefrom.

page_text: For this purpose I, first, wash the precipitate with hot water to
remove soluble salts. If it is desired to wash out sulphate of lead a
little common salt is added, or the washings are used over and over
again until they contain sufficient salt to dissolve sulphate of lead.
The copper or copper and lead in the washings may be precipitated
by metallic iron or in any convenient way.
Second. To dissolve iron I wash the precipitate with weak sulphuric
or hydrochloric acid, the washings being used over and over again, with
the addition of a little strong acid, until the solution of sulphate or
chloride of iron is of sufficient strength to crystallize. After precipitating
any copper which may have been dissolved, I run the solution of sulphate
or chloride of iron into tanks and allow it to crystallize. After these
two operations the precipitate is sufficiently purified to be at once smelted
into metallic copper.
Third. Should the said copper precipitate contain sufficient silver to
pay for extraction, I thoroughly oxidize the precipitate after the second
operation in a box furnace, and then dissolve out the silver with hot
strong brine or hyposulphate of soda; the silver in solution is then
precipitated by copper, the copper in its turn being precipitated by iron.
The purified oxide of copper is now in a fit condition either to be smelted
at once to bring forward copper regulus, or otherwise to be employed, as
best suits the smelter.
Fourth. To produce sulphate of copper, the oxide of copper fresh from
the box furnace, mentioned in the third operation, is dissolved in
sulphuric acid in the ordinary way. The silver and gold, or either silver 2
or gold contained in the oxide, remain undissolved, their concentration
being great on account of the iron having been previously removed.
Any silver dissolved by the sulphuric acid is precipitated by hydrochloric
acid

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Hawke Dennis in the Great Seal Patent
Office on the 28th November 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
HAWKE DENNIS, of Liverpool, in the County of Lancaster, Commission
Merchant, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of May, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said James Hawke Dennis, Her special
licence that I, the said James Hawke Dennis, my executors, adminis-
trators, and assigns, or such others as I, the said James Hawke Dennis,
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 "IMPROVEMENTS
IN THE TREATMENT OF COPPER PRECIPITATE, AND IN THE UTILIZATION OF IM-
PURITIES CONTAINED THEREIN," upon the condition (amongst others) that
I, the said James Hawke Dennis, my executors or administrators, by
an instrument in writing under my, or their, or one of 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 I, the said James Hawke Dennis, do hereby
declare the nature of my said Invention, 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 :—
The object of my Invention is to purify commercial copper precipitate
obtained by the wet method of extracting copper from its orcs, and to
utilize some of the metallic impurities extracted therefrom.

page_text: For this purpose I,
remove soluble salts.
little common salt is
first, wash the precipitate with hot water to
If it is desired to wash out sulphate of lead a
added, or the washings are used over and over
again until they contain sufficient salt to dissolve sulphate of lead. The
copper or copper and lead in the washings may be precipitated by
metallic iron or in any convenient way.
Second. To dissolve iron I wash the precipitate with weak sulphuric
or hydrochloric acid, the washings being used over and over again with
the addition of a little strong acid until the solution of sulphate or
chloride of iron is of sufficient strength to crystallize. After precipitating
any copper which may have been dissolved, I run the solution of sulphate
or chloride of iron into tanks and allow it to crystallize. After these
two operations the precipitate is sufficiently purified to be at once smelted
into metallic copper.
Third. Should the said copper precipitate contain sufficient silver to
pay for extraction, I thoroughly oxidize the precipitate after the second
operation in a box furnace, and then dissolve out the silver with hot
strong brine or hyposulphite of soda; the silver in solution is then
precipitated by copper, the copper in its turn being precipitated by iron.
The purified oxide of copper is now in a fit condition either to be smelted
at once to bring forward copper regulus, or otherwise to be employed, as
best suits the smelter.
Fourth. To produce sulphate of copper, the oxide of copper fresh from
the box furnace, mentioned in the third operation, is dissolved in
sulphuric acid in the ordinary way. The silver and gold, or either silver
or gold contained in the oxide remain undissolved, their concentration
being great on account of the iron having been previously removed.
Any silver dissolved by the sulphuric acid is precipitated by hydrochloric
acid.
Ordinary metalurgical washing and precipitating apparatus is found
to answer well in the operations above mentioned.
Having now described the nature of my said Invention, and parti-
cularized the same, I claim, the treatment and purification of copper

page_text: precipitate and the several modes of utilizing the impurities, substantially
as herein set forth.
In witness whereof, I, the said James Hawke Dennis, have here-
unto set my hand and seal, the Twenty-sixth day of November,
in the year of our Lord One thousand eight hundred and seventy-
two
In the presence of
FRANCIS E. PENN,
2, Oriel Chambers,
Liverpool.
JAMES HAWKE DENNIS. (L.B.)