IMPROVEMENTS IN THE MANUFACTURE OF CULORATE OF POTASH
Year: 1884

page_text: I, JAMES WILSON of Berwick-on-Tweed Manufacturing Chemist do hereby declare
the nature of the said invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CULORATE OF POTASH " to be as follows:-
:
This Invention which relates to improvements in the manufacture of Chlorate
of Potash consists in substituting Oxide of Magnesia, commonly known as
Magnesia, for lime which has hitherto been used as a re-agent in the process for
making the aforesaid Chlorate of Potash and the result of the said substitution is
that the Magnesia and Hydro-chloric acid are both recovered.
The process for manufacturing Chlorate of Potash under these improvements
consists in passing Chlorine gas through a mixture of magnesia and Chloride of
Potassium in water.-When the re-action resulting from the admixture of tho
aforesaid substances is completed I introduce steam thereinto so as to drive off the
uncombined chlorine, I then evaporate the resulting liquid to the crystallizing
point and discharge it into crystallizing vessels and allow the Chlorate of Potassium
to crystallize out, whilst the magnesia Chloride remains in solution.-When the
crystallization is completed I run the resulting mother liquor, that is to say the
magnesia chloride, into an iron pan and evaporate it until a sample, on cooling,
solidifies. This liquor is then run into a muffle furnace and reduced to dryness.-
The hydro-chloric acid which is given off being led to a condenser and collected.
In order to recover the residual Hydro-chloric acid this dried residue is broken
up and heated to redness in a current of steam.-The resulting Magnesia is then
ground for further use.
The proportions of substances used in the aforesaid process which I have found
to answer, are,
Potassium Chloride 1 part by weight
Magnesia
1.75 parts by weight.
In practising the Invention, by preference a series of vessels are employed.—The
Potassium Chloride and Magnesia with water are placed in the topmost vessel and
the chlorine is passed by a pipe into the bottom of the lowest vessel of the series so
that it passes upwards by other pipes through the liquor in the series, becoming
gradually absorbed.-The liquor in each of the vessels is isolated therein, being
allowed to descend from vessel to vessel as required until it reaches the lowest
vessel wherein it is saturated with chlorine.
The said vessels are furnished with agitators for the purpose of more rapidly
causing the absorption of the chlorine and with stop-cocks and pipes for discharging
the liquor from vessel to vessel.
Dated this fourth day of April 1884.
:
J. H. JOHNSON, DAY & JOHNSON,
Petitioner's Agents,
115, St. Vincent Street, Glasgow.

page_text: I JAMES WILSON, of Berwick-on-Tweed, Manufacturing Chemist do hereby declare
the nature of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CHLORATE OF POTASH," and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
My invention, which relates to improvements in the manufacture of Chlorate of
Potash, consists in substituting Magnesia for Lime which is generally used as a
re-agent in the process, and in the manner of carrying out the process whereby not
only is the Magnesia recovered in a state fit for use over again, but the Chlorine
which by the usual process is run away waste as Chloride of Calcium is also
recovered, partly as Chlorine and partly as Hydrochloric Acid, and likewise the
Potassium which remains in the mother-liquors as Chlorate is recovered as Chloride.
In carrying out the process under these improvements, Chlorine gas is passed
through a series of vessels containing water in which is suspended a mixture of
Magnesia and Chloride of Potassium in suitable proportions-1 part of Chloride of
Potassium to 175 part Magnesia I have found to answer well. These vessels
I prefer to have placed one above another so that their contents may be run from
one to another, the Chlorine being conducted into the lowermost one first and
passing upwards from vessel to vessel, whilst the liquor containing the Mixture of
Magnesia and Chloride of Potassium is run downwards from vessel to vessel as
required until it reaches the lowermost one wherein it is saturated with Chlorine.―
The vessels are furnished with agitators to cause the more rapid absorption of the
Chlorine.
When the re-action is complete, I blow steam into the mixture or otherwise heat
it so as to drive off any uncombined Chlorine.-This operation being conducted in
- a closed vessel so that the evolved Chlorine may be collected and utilized.―The
liquor is then evaporated and the Chlorate of Potash crystallized out.
The mother-liquor consisting of a solution of Chloride of Magnesium containing
a small quantity of Chlorate of Potash is concentrated until a sample, on cooling,
solidifies, and is then run into a muffle furnace and reduced to dryness. In carrying
out this part of the operation. I prefer that the concentrated liquor should be run
into the furnace in a constant stream, a small quantity of Magnesia having pre-
viously been placed therein, so as to absorb the liquor and prevent it adhering to
the bed of the furnace. The mixture of Magnesia and concentrated liquor rapidly
dries, and when a sufficient quantity of dried material has accumulated, it is
removed to a hotter part of the furnace and gradually heated to redness.—I find
that it is not essential to introduce steam into the furnace, as the decomposition of the
Chloride of Magnesium is sufficiently complete without it.--It is of course necessary
to run the mother-liquor into the concentrating vessel in a constant stream also,
so that the liquor therein may always be as nearly of the same strength as
possible.
The Chlorine of the Chloride of Magnesium is by this process, given off partly as
Chlorine and partly as Hydrochloric Acid, and any Chlorate of Potash remaining
in the mother-liquor is converted into Chloride of Potassium, and remains as such
along with the Magnesia.
said
Having now particularly described and ascertained the nature of my
Invention, and in what manner the same is to be performed, I declare that what
1 claim is :-
First In the manufacture of Chlorate of Potash, the passing of Chlorine through
a mixture of Chloride of Potassium and Magnesia in water, substantially as herein-

page_text: Second In the manufacture of Chlorate of Potash, the arrangement of vessels
for treating the mixture of Chloride of Potassium, Magnesia and water with
Chlorine substantially as hereinbefore set forth.
Third In the manufacture of Chlorate of Potash, the treating of the mother-
liquor by evaporating it until a sample, on cooling, solidifies, and then running the
said liquor preferably in a constant stream into a muffle furnace and subsequently
operating thereon substantially as hereinbefore set forth.
Dated this Third day of January 1885
J. H. JOHNSON, DAY & JOHNSON,
Applicant's Agents.