IMPROVEMENTS IN TREATING SULPHURETS
Year: 1860

page_text: LETTERS PATENT to Andrew George Hunter, of 43, Dean Street, New-
castle-upon-Tync, for the Invention of "IMPROVEMENTS IN TREATING
SULPHURETS"
Sealed the 2nd April 1861, and dated the 19th October 1860.
PROVISIONAL SPECIFICATION left by the said Andrew George Hunter
at the Office of the Commissioners of Patents, with his Petition,
on the 19th October 1860.
I, ANDREW GEORGE HUNTER, of 43, Dean Street, Newcastle-upon-Tyne,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN TREATING
SULPHURETS," to be as follows:-
This Invention has for its object the conversion of sulphurets of potassium
and sodium into metallic oxides or carbonates of oxides, and the utilization of
the sulphur evolved. I effect this by means of steam, either alone or mixed
with other gases or substances capable of supplying either oxygen, hydrogen,
or carbonic acid, in such proportions as shall convert the sulphuret into an
oxide or carbonate of oxide without converting it into a sulphate, sulphite, or
hyposulphite, applied to the sulphuret either along or mixed with other
matters while at a high temperature, or by preference in a state of fusion. I
prefer forcing the steam or mixture of steam with other gases through and
among the sulphuret, either broken into small pieces and at a high temperature:
or in a state of fusion, and it is maintained at the high temperature or in a
Die d

page_text: state of fusion by the heat evolved from the decomposition and combinations
effected by the action of the gases introduced, and when the heat evolved from
this source is from any cause insufficient to maintain the sulphuret at a
sufficiently high temperature, or by preference in a state of fusion, artificial
heat must be applied, either by employing the steam or other mixture of gases
in a superheated state; or if this is not sufficient, additional artificial heat
must be applied to the sulphuret. When I desire to produce a metallic oxide,
I employ steam, or a mixture of steam with other gases free from carbonic
acid; and when I desire to produce a carbonate of the metallic oxide, I
employ steam, or a mixture of steam with other gases containing carbonic
acid; or I convert the previously formed metallic oxide into a carbonate, by
exposing it either in a dry or moist state, or dissolved in water to the action
or carbonic acid, or by roasting in contact with air a mixture of oxide and
carbonaceous matter, such as sawdust or small coal, and subsequently freeing
(when necessary) the carbonate so produced from mechanically adhering
impurities by any of the processes well known to chemists. The oxides of
potassium or sodium, or the carbonates of potash or soda produced by any of
these processes are available for any of the purposes to which these compounds
are usually applied. The gasses resulting from the decomposition of the
sulphuret are chiefly hydro-sulphuric acid, occasionally accompanied with
sulphurous acid and sulphuret of carbon, according to the gases applied. I
convert the hydro-sulphuric acid either by combustion into sulphurous acid,
and thence by means of nitre, as commonly practised, into sulphuric acid; or
I convert it and any sulphurous acid present into sulphur, by converting by
combustion a portion of it into sulphurous acid, and causing the said sulphurous
acid to act on the remainder of the hydro-sulphuric acid at such temperatures
and in such proportions as are suitable for their mutual decomposition into
water and sulphur without the formation of pentathionic acid. The sulphur
thus formed may be collected and used for any of the purposes in which
sulphur is ordinarily employed. In the decomposition of hydro-sulphuric acid
and sulphurous acid before mentioned it occasionally happens that there is an
excess of sulphurous acid employed, or that pentathionic acid is produced, in
either of which cases after I have obtained all the sulphur produced by
the decomposition, I pass the remaining gases through a layer of red-hot coke
or other carbonaceous matter, which deprives the sulphurous or pentathionic
acids of their oxygen, leaving the sulphur free, which I collect, care being
taken to avoid the formation of sulphuret of carbon; but which, if produced,
I utilize the sulphur it contains by reforming it into sulphurous acid by com-
bustion, and applying the sulphurous acid so produced to the decomposition of

page_text: a fresh quantity of hydro-sulphuric acid, as before explained, in which case
the sulphurous acid thus obtained substitutes to an equal amount that
obtained by the combustion of hydro-sulphuric acid, and thereby obviates
the necessity of producing a corresponding quantity from hydro-sulphuric
acid by combustion.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Audrew George Hunter in the Great Seal Patent Office on
the 19th April 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANDREW
GEORGE HUNTER, of 43, Dean Street, Newcastle-upon-Tyne, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth 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
me, the said Andrew George Hunter, Her special licence that I, the said.
Andrew George Hunter, my executors, administrators, and assigns, or such
others as I, the said Andrew George Hunter, 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN TREATING SULPHURETS," upon the con-
dition (amongst others) that I, the said Andrew George Hunter, 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 Andrew George Hunter, 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 thereof, that is to say :-
In following out my Invention several forms of apparatus and modifications
of process may be used without departing from the main features of my Inven-
tion, and among others I have found the following to do well:-I produce the

page_text: sulphurets either of potassium or sodium by heating the corresponding
sulphates in a suitable furnace in contact with carbonaceous matter in manner
as has been previously done by others, and when the sulphates are sufficiently
decomposed I remove the fluxed mass, consisting chiefly of sulphuret and
carbonaceous matter in a state of fusion into a previously heated vessel,
capable of standing the necessary heat, and provided with the means of
applying artificial heat, should such be necessary, to the sulphuret while in
progress, and provided with suitable pipes for the admission of steam, air, or
other gases capable of supplying either oxygen, hydrogen, or carbonic acid, in
such proportions as shall convert, the sulphuret into an oxide, or carbonate
of oxide without converting it into a sulphate, sulphite, or hyposulphite.
I prefer using steam in a superlicated state at as high a temperature as I can
conveniently obtain without volatilizing the caustic alkali to too great an
extent, and forcing it through and among the fused mass, and the decomposition
and combinations thereby produced are usually sufficient to maintain the mass
in a fused state. I find a vessel formed of cast-iron slabs or bricks very
suitable for this part of the process. When the sulphuret is all or nearly all
decomposed and converted into an oxide or carbonate of oxide, which may be
known by testing for sulphurets (as commonly practised by chemists) a small
portion of the fused mass removed for this purpose, and by the appearance
and smell of the gases evolved, I remove the fused product, and allow it to
cool either in moulds or in mass, and when cool it is ready for many of the
purposes to which caustic or carbonated alkalies are applied, but it is too
impure for some purposes, and when I desire to purify the product 1 either
do so by allowing the fused product to remain at a high temperature, and as
nearly at rest as its temperature will permit in a vessel provided with the
means of applying sufficient artificial heat to maintain the mass in a fused
state; and when the mechanical impurities have thus separated from thegreat
bulk of product, I remove the clear fused product and allow it to cool, and the
part containing the impurities I purify by the following process, which is also
applicable to purifying the whole mass without the settling just described:-
I dissolve the cooled product in water, filter the solution, or allow the
mechanical impurities to settle from the solution, remove and boil down to
dryness the clear liquor, and should the fused product have consisted chiefly of
an oxide, but contained any sulphates or carbonates, I remove these from the
solution in the boiling down by fishing the salts, so long as these consist chiefly
of sulphates, out from the liquor as it boils, and should it contain any
undecomposed sulphuret, I convert it into sulphate by acting on the liquor
with nitre, as commonly practised by others in making caustic alkalies by

page_text: the present methods. Should I desire to convert a sulphuret into a carbonate
of oxide I can do so by using steam mixed with carbonic acid for the
decomposition of the sulphuret; but I prefer to form the sulphuret into an
oxide, dissolve the product in water, and either expose the solution to the
action of carbonic acid by any of the means well known to chemists, or by
boiling it down mixed with sawdust or other carbonaceous matter,and roasting;
or, as this process which is well known is called "carbonating" the oxide.
The carbonate so produced may be used as such, or may be purified by any of
the meaus well known to chemists. I effect the utilization or recovery of the
sulphur evolved by any of the means well known to chemists for this object.
What I claim as new and forming the essential features of this Invention
is, the mode of decomposing sulphurets of potassium and sodium, and con-
verting them into oxides or carbonates of oxides by means of steam, air,
carbonic acid, and other gases, and carbonating the so formed oxide by means
of carbonic acid or carbonaceous matter.
In witness whereof, I, the said Andrew George Hunter, have hereunto
set my hand and seal, this Third day of April, in the year of our Lord
One thousand eight hundred and sixty-one.
ANDREW GEORGE HUNTER. (.s.)