IMPROVEMENTS IN UTILISING BYE PRODUCTS OF THE SODA AND POTASH MANUFACTURES, AND IN APPARATUS THEPROD
Year: 1882

page_text: LETTERS PATENT to James Mactear, of Glasgow, in the County of Lanark,
North Britain, Chemist for an Invention of "IMPROVEMENTS IN UTILISING
BYE PRODUCTS OF THE SODA AND POTASH MANUFACTURES, AND IN APPARATUS
THEPROD"
PROVISIONAL SPECIFICATION left by the said James Mactear at the Office
of the Commissioners of Patents on the 22nd November 1882.
JAMES MACTEAR, of Glasgow, in the County of Lanark, North Britain, Chemist,
"IMPROVEMENTS IN UTILISING BYE PRODUCTS OF THE SODA AND POTASH MANU-
FACTURES AND IN APPARATUS THEREFOR
"
This Invention has for its object the economical and satisfactory utilisation of
what has been known as alkali waste and is a bye product of the soda and potash
manufactures.
In carrying out the Invention according to one modification the waste consisting
principally of sulphides of calcium is put into vessels capable of sustaining a
moderate pressure above the atmosphere, and after being mixed with sufficient
water, is treated with carbonic acid under pressure and aided by heat. Carbonate
of lime and sulphuretted hydrogen are formed; and the latter is subsequently
made to mingle with sulphurous acid in presence of water or a solution of chloride
of calcium the sulphur being thereby separated
The carbonic acid employed may be that formed from coal in ordinary furnaces,
or evolved from lime kilns or from any other economical source; and pumps or
equivalent mechanical means are employed to force it through the vessels con-
taining the alkali waste. Several of these vessels are by preference employed in
combination, and, the process being conducted so as to be at different stages in the
several vessels or sets of vessels, the carbonic acid (with the gases associated with
it) is made to pass in succession through vessels in which the operation is less and
less advanced so as to be finally exhausted as far as practicable. The sulphuretted
hydrogen evolved in the vessels will pass off with the unabsorbed gases and will
be led by pipes to the apparatus in which the next operation takes place. This
operation may be conducted in closed vessels fitted with mechanical agitators, or
wholly or partly in towers down which water or a solution of chloride of calcium

page_text: is made to descend, whilst the sulphuretted hydrogen and sulphurous acid are
introduced at the lower part. The sulphurous acid used may be obtained by
burning a part of the sulphur resulting from previous operations or from pyrites
burners or in any other suitable known way.
In a second modification of the processes the sulphur compounds may be dissolved
out of the alkali waste with the aid of heat and pressure, and the solution after
being separated may be treated with carbonic acid as herein before described or it
may be mixed with "yellow" "liquor" before being so treated.
The latter part of the processes may be modified by passing the sulphuretted
hydrogen and sulphurous acid gases into or through water which will cause the
sulphur to be separated and held in suspension in a finely divided state. The
sulphurous acid should in all cases be kept in excess; and in many cases it will be
convenient and advantageous for the improved processes herein before described and
which are applicable directly to the alkali waste, to be worked in combination
with the present applicant's well known process for recovering sulphur from
yellow liquor-one modification of which process is described in the Specification of
Letters Patent granted to him and dated 8 September 1871 (No 2374). The
sulphurous acid which has to be used in both processes is most conveniently pro-
duced in a continuous manner, and when employed in the new process the
surplus may be utilised in the old process, whilst between the separate charges
worke in the new process the entire production of sulphurous acid may be used in
the old process, or when sulphuretted hydrogen and sulphurous acid are passed
into or through water as herein before described so as to yield a solution of the
excess of sulphurous acid with sulphur in suspension, this mixture may be used
instead of the simple solution of sulphurous acid in the process described in the
Specification herein before referred to.
The carbonate of lime resulting from the first part of the new process has mixed
or associated with it coal or carbon remaining unconsumed in the earlier stages of
the manufacture together with some other matters; and by the present Invention
this circumstance is turned to account in utilising these residuary matters, or
similar matters obtained in otherwise dealing with alkali waste, by employing
them in the manufacture of a cement more or less like Portland cement.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Mactear in the Great Seal Patent Office on the 19th May
1883.
į
JAMES MACTEAR, of Glasgow, in the County of Lanark, North Britain, Chemist,
"IMPROVEMENTS IN UTILISING BYE PRODUCTS OF THE SODA AND POTASH MANU-
FACTURES AND IN APPARATUS THEREFOR
"
My said Invention has for its object the economical and satisfactory utilisation
of what has been known as alkali waste and is a bye product of the soda and
potash manufactures.
In carrying out my Invention the waste consisting principally of sulphides of
calcium is put into vessels capable of sustaining a moderate pressure above the
atmosphere, and after being mixed with sufficient water, is treated with carbonic
acid under pressure and aided by heat. A pressure of about 20 pounds per square
inch is what I prefer to use, but any pressure not less than five pounds per square
inch will answer the purpose more or less advantageously. Carbonate of lime and
sulphuretted hydrogen are formed; and the latter is subsequently made to mingle
with sulphurous acid in presence of water or a solution of chloride of calcium, the
sulphur being thereby separated.
The carbonic acid employed may be that formed from coal in ordinary furnaces,
or evolved from lime kilns, or from any other economical source; and pumps or
equivalent mechanical means are employed to force it through the vessels
containing the alkali waste. Several of these vessels are by preference employed
in combination, and the process being conducted so as to be at different stages in
the several vessels or sets of vessels, the carbonic acid (with the gases associated
with it) is made to pass in succession through vessels in which the operation is less
and less advanced, so as to be finally exhausted as far as practicable. The
sulphuretted hydrogen evolved, in the vessels will pass off with the unabsorbed
gases, and will be led by pipes to the apparatus in which the next operation takes
place. This operation may be conducted in closed vessels fitted with mechanical
agitators, or wholly or partly in towers down which water or a solution of chloride
of calcium is made to descend, whilst the sulphuretted hydrogen and sulphurous.
acid are introduced at the lower part. The sulphurous acid used may be obtained
by burning a part of the sulphur resulting from previous operations, or from
pyrites burners or in any other suitable way.
The first part of my improved process may be modified by dissolving out the
sulphur compounds from the alkali waste with the aid of heat and pressure, and
after separating the solution mixing with it what is known as "yellow liquor'
and treating the mixture with carbonic acid.
"
The latter part of the process may be modified by passing the sulphuretted
hydrogen and sulphurous acid gases into or through water, which will cause the
sulphur to be separated and held in suspension in a finely divided state. The
sulphurous acid should in all cases be kept in excess; and in many cases it will be
convenient and advantageous for the improved processes hereinbefore described, and
which are applicable directly to the alkali waste, to be worked in combination with
my well known process for recovering sulphur from yellow liquor, one modification
of which process is described in the Specification of my patent officially numbered
2374 of 1871. The sulphurous acid, which has to be used in both processes, is
most conveniently produced in a continuous manner, and when employed in my
new process the surplus may be utilised in the old process; whilst between the
separate charges worked in the new process the entire production of sulphurous

page_text: acid may be used in the old process. Or when sulphuretted hydrogen and
sulphurous acid are passed into or through water, as hereinbefore described, so as to
yield a solution of the excess of sulphurous acid with sulphur in suspension, this
mixture may be used instead of the simple solution of sulphurous acid in the
process described in my earlier Specification hereinbefore referred to.
The carbonate of lime resulting from the first part of my new process has mixed
or associated with it coal or carbon remaining unconsumed in the earlier stages of
the manufacture together with some other matters; and by my present Invention
I turn this circumstance to account in utilising these residuary matters, or similar
matters obtained in otherwise dealing with alkali waste, by employing them in the
manufacture of a cement more or less like Portland cement.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that what I believe to be novel and original
and claim as the Invention secured to me by and in terms of the herein before
in part recited Letters Patent is :—
1. The combination of processes for utilising alkali waste consisting in first
treating the waste mixed with water with carbonic acid aided by heat and pressure,
and in afterwards treating the resulting sulphuretted hydrogen with sulphurous
acid in the presence of water or a solution of chloride of calcium in order to
separate the sulphur substantially as hereinbefore described.
2. The combination of processes for utilising alkali waste consisting in first
obtaining from the waste by the aid of heat and pressure a solution of sulphur
compounds, in secondly mixing such solution with yellow liquor, in thirdly
treating the mixture with carbonic acid, and in fourthly treating the resulting
sulphuretted hydrogen with sulphurous acid in the presence of water or a solution
of chloride of calcium in order to separate the sulphur substantially as hereinbefore
described.
3. The combining of the processes for treating the sulphuretted hydrogen with
my older process for treating yellow liquor substantially as and for the purposes
herein before described.
In Witness whereof I, the said James Mactear, have hereunto set my hand
and seal this eighteenth day of May in the year of our Lord One
thousand eight hundred and eighty-three.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES MACTEAR. (L.S.)