IMPROVEMENTS IN UTILISING BYE PRODUCTS OBTAINED IN THE MANU- FACTURE OF ALKALI, AND IN TREATING CUPREOUS AND OTHER METALLIC SOLUTIONS AND COMPOUNDS
Year: 1871

page_text: LETTERS PATENT to Thomas Rowan, of Glasgow, in the County of
Lanark, North Britain, Manufacturing Chemist, for the Invention
of "IMPROVEMENTS IN UTILISING BYE PRODUCTS OBTAINED IN THE MANU-
FACTURE OF ALKALI, AND IN TREATING CUPREOUS AND OTHER METALLIC
SOLUTIONS AND COMPOUNDS."
Sealed the 5th March 1872, and dated the 9th September 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Rowan at
the Office of the Commissioners of Patents, with his Petition, on
the 9th September 1871.
I, THOMAS ROWAN, of Glasgow, in the County of Lanark, North
Britain, Manufacturing Chemist, do hereby declare the nature of the
said Invention for. "IMPROVEMENTS IN UTILISING BYE PRODUCTS OBTAINED IN
the Manufacture OF ALKALI, AND IN TREATING CUPREOUS AND OTHER Metallic
SOLUTIONS AND COMPOUNDS," to be as follows, that is to say:-
This Invention has principally for its object the utilisation of certain
bye products known as "alkali waste," and obtained in the manufacture

page_text: of alkali, and also comprises a mode of treating cuprcous and other
metallic solutions and compounds with an agent obtained from such
waste, or with the same agent obtained otherwise.
In practising the Invention bydrochloric acid is added to the alkali
waste, and causes the separation of sulphuretted hydrogen, leaving
calcium chloride; or the sulphuretted hydrogen may be separated by
treating the alkali waste with steam, either saturated or superheated; or
of high pressure, leaving lime. The sulphuretted hydrogen thus obtained
is passed through the solutions of copper obtained in the wet process of
obtaining copper from its ores, instead of the copper being precipitated
by iron, as ordinarily practised, whereupon the copper, arsenic, and other
metals in solution will be precipitated as sulphides. It is preferred to
conduct this process under a pressure of a few pounds per square inch
above the atmosphere. The precipitated metallic sulphides may be
roasted, when copper oxide will be left, arsenic and other volatile metals
passing off with the sulphurous acid. When the copper solution has
been obtained by dissolving the mixture obtained by roasting copper ore
and common salt, sulphate of soda will be left after the metals are
precipitated, and may be crystalised out.
The process may be applied to the liquors obtained by condensing the 2
fumes arising from the roasting of copper ore and salt, in which case the
alkali waste may be added to the liquor, whereupon the acid present will
cause the separation of sulphuretted hydrogen, which will induce the
precipitation of the copper and other metals as sulphides as before.
In a similar way the sulphuretted hydrogen obtained as herein-before
described may be used for precipitating other metals as sulphides from
solutions, which may be alkaline or acid according to circumstances,
and in order to utilise the sulphur by roasting and converting into
sulphuric acid. Or, instead of roasting the copper or other metallic
sulphide, it may be treated with steam, whereby copper oxide will be
formed and sulphuretted hydrogen will be driven off, and the latter may
be used for precipitating fresh quantities of copper or other metal.
This last improvement is obviously applicable, whatever be the original
source of the sulphuretted hydrogen.

page_text: SPECIFICATION in pursuance, of the conditions of the Letters Patent,
filed by the said Thomas Rowan in the Great Seal Patent Office
on the 8th March 1872..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
ROWAN, of Glasgow, in the County of Lanark, North Britain, Manu-
facturing Chemist, send greeting.
4
}
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of September, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Rowan, Her special licence
that I, the said Thomas Rowan, my executors, administrators; and
assigns, or such others as I, the said Thomas Rowan, 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 UTILISING BYE PRODUCTS OBTAINED IN THE MANUFACTURE OF ALKALI,
AND IN TREATING CUPREOUS AND OTHER METALLIC SOLUTIONS AND COMPOUNDS,"
upon the condition (amongst others) that I, the said Thomas Rowan,
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.
1.
".
.
:
NOW KNOW YE, that I, the said Thomas Rowan, 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 in writing, that is to say:-
My said Invention has principally for its object the utilisation of
certain bye products known as "alkali waste," and obtained in the
manufacture of alkali, and also comprises a mode of treating cupreous

page_text: .
and other metallic solutions and compounds with an agent obtained from
such waste, or with the same agent obtained otherwise.
In practising my said Invention hydrochloric acid is added to the
alkali waste and causes the separation of sulphuretted hydrogen, leaving
calcium chloride; or the sulphuretted hydrogen may be separated by
treating the alkali waste with steam, either saturated or superheated, or
of high pressure, leaving lime. The sulphuretted hydrogen thus
obtained is passed through the solutions of copper, obtained in the wet
process of obtaining copper from its ores, instead of the copper being
precipitated by iron as ordinarily practised, whereupon the copper,
arsenic, and other metals in solution will be precipitated as sulphides.
I conduct this process under a pressure of five pounds or upwards per
square inch above the atmosphere. The precipitated metallic sulphides
may be roasted, when copper oxide will be left, arsenic and other
volatile metals passing off with the sulphurous acid. When the copper
solution has been obtained by dissolving the mixture obtained by
roasting copper ore and common salt sulphate of soda will be left after
the metals are precipitated, and may be crystalised out.
The process may be applied to the liquors obtained by condensing the
fumes arising from the roasting of copper ore and salt, in which case the
alkali waste may be added to the liquor, whereupon the acid present
will cause the separation of sulphuretted hydrogen, which will induce
the precipitation of the copper and other metals as sulphides as before.
In a similar way the sulphuretted hydrogen obtained as herein-before
described may be used for precipitating other metals as sulphides from
solutions, which may be alkaline or acid according to circumstances;
and in order to utilise the sulphur by roasting and converting into
sulphuric acid. Or, instead of roasting the copper or other metallic
sulphide it may be treated with steam, whereby copper oxide will be
formed and sulphuretted hydrogen will be driven off, and the latter may
be used for precipitating fresh quantities of copper or other. metal.
This last improvement is obviously applicable whatever be the original
source of the sulphuretted hydrogen.
In practically carrying it out the sulphide (of copper for example) is
allowed to settle and the supernatant liquor is run off. The precipitate
is washed once with water and is then well drained, after which it is
heated to redness in a revolving muffle or other suitable furnace, and the

page_text: steam is passed over it.
the heating operation it
Should any sulphate of the metal be formed in
may be dissolved out from the metallic oxide
and be added to fresh liquors to be precipitated by the sulphuretted
hydrogen. When manganese is the metal of the salt treated the
resulting oxide forms a useful pigment.
Having thus particularly described my said Invention and the manner
of performing the same I have to state that I do not restrict myself to
the precise details herein-before referred to, but that what I believe to
be novel and original, and claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,-
1. The treating of cupreous and other metallic solutions with sul-
phuretted hydrogen under pressure, as and for the purposes herein-
before described.
2. The treating of cupreous and other metallic solutions with sul-
phuretted hydrogen obtained repeatedly from the sulphides formed by
such treatment, as and for the purposes herein-before described.
In witness whereof, I, the said Thomas Rowan, have hereunto set
my hand and seal, this Second day of March, in the year of
our Lord One thousand eight hundred and seventy-two.
0
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
THOMAS ROWAN. (L.S.)