AN IMPROVED METHOD OR PROCESS FOR THE PURIFI- CATION OF ALKALINE SOLUTIONS
Year: 1883

page_text: LETTERS PATENT to Thomas Glover of Runcorn, in the County of Cheshire,
for an Invention of "
'AN IMPROVED METHOD OR PROCESS FOR THE PURIFI-
CATION OF ALKALINE SOLUTIONS
"
PROVISIONAL SPECIFICATION left by the said Thomas Glover at the Office
of the Commissioners of Patents on the 1st June 1883.
THOMAS GLOVER, of Runcorn in the County of Cheshire "AN IMPROVED
METHOD OR PROCESS FOR THE PURIFICATION OF ALKALINE SOLUTIONS
"
My invention relates to the purification of alkaline solutions which contain
sulphides.
Hitherto impure alkaline solutions or lyes have been freed from sulphides by
the addition thereto of solutions of zinc or of zinc oxide in caustic soda, or by the
direct introduction of the zinc or zinc oxide, in the solid form, into the lyes to be
purified. But according to my improved method or process I remove the said
sulphides by the addition of a native carbonate of zinc, such as calamine, to the
alkaline solutions or lyes until only a trace of sulphide remains, that is to say, I
use the native carbonate either in its ordinary state or after it has been washed
with water in order to remove any clayey matter which it may contain, or after it
is ground to a powder. Either the native carbonate is added to the liquors to be
purified, with or without the application of heat and agitation; or it is dissolved in
"vat liquor," the solution thus formed being added to the impure alkaline solutions
or lyes; or it is dissolved in caustic alkali and the solution thus formed is added
to the impure alkaline solutions or lyes, the native carbonate, or the solutions
thereof, being added until only a trace of sulphide remains.
In the purification of the alkaline solutions or lyes for the manufacture of the
caustic alkalies my improved process is carried on either in the vat liquors before
the causticising operation is commenced, or during the causticising operation, but
before the latter operation is concluded, I thus obtain the distinct advantages of a
cheap method of purifying alkaline solutions and, in the production of soda ash,
the impurity (sulphide of sodium) is converted into carbonate of soda, an advantage
not derived from other methods of purification.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Glover in the Great Seal Patent Office on the 1st December
1883.
THOMAS GLOVER, of Runcorn, in the County of Cheshire,
"AN IMPROVED
METHOD OR PROCESS FOR THE PURIFICATION OF ALKALINE SOLUTIONS
"
My invention relates to the purification of alkaline solutions which contain
sulphides.
Hitherto impure alkaline solutions or lyes have been freed from sulphides by
the addition thereto of solutions of zinc or of zinc oxide in caustic soda, or by the
direct introduction of the zinc or zinc oxide, in the solid form, into the lyes to be
purified. These processes or methods of purification are, however, expensive and
do not present any peculiar advantage. But by my invention I provide a cheap
method or process of purifying alkaline solutions or lyes, which method or process
has the advantage, over those heretofore employed, that, when used in the
production of soda-ash, the impurity (sulphide of sodium) will be converted into
carbonate of soda.
I accomplish this result by employing a native carbonate of zinc, such as
calamine, in the manner hereinafter described.
In carrying my improved method or process into effect, I take the native
carbonate of zinc, either in its ordinary state, or after it has been washed with
.water to remove any clayey matter which it may contain, or after it has been
ground to a powder, and dissolve the same in a solution of caustic alkali, preferably
free from sulphide. I add the solution thus formed to the impure alkaline solutions
or lyes until only a trace of sulphide remains. I might add a sufficient quantity
of the said solution to the impure alkaline solution or lye to entirely remove the
sulphide therefrom, but, in order to avoid the risk of introducing an excess of
zine, I prefer to leave a trace of sulphido in the said solution or lye.
In the purification of alkaline solutions or lyes for the manufacture of caustic
alkalies, my improved process is carried on either in the "vat-liquors" before the
causticising operation is commenced, or during the causticising operation, but before
the latter operation is concluded.
The native carbonate of zinc may, if desired, be added in its crude state to the
solutions to be purified, with or without the application of heat and agitation; or
it may be dissolved in "vat-liquor," the solution thus formed being added to the
impure alkaline solution or lye.
Having thus fully described my said invention and the manner of performing
the same I wish it understood that I claim :-
The improved method or process of purifying alkaline solutions by means of a
solution of a native carbonate of zinc, such as calamine, in caustic alkali, sub-
stantially as above set forth.
In witness whereof I the said Thomas Glover have hereunto set my hand and
seal this Twenty eighth day of November in the year of Our Lord One thousand
eight hundred and eighty three.
THOMAS
קיעים זו