Improvements in or Appertaining to the Separation of Chlorate of Potash (and if Desirable the Chloride of Calcium or Magnesium, or other similar Salt in the Mother Liquor) from Solutions thereof.
Year: 1888

page_text: Date of Application, 20th Oct., 1888
Complete Specification Left 13th Apr 1889-Accented. 28th Sept. 1889
PROVISIONAL SPECIFICATION.
Improvements in or Appertaining to the Separation of Chlorate of
Potash (and if Desirable the Chloride of Calcium or Magnesium,
or other similar Salt in the Mother Liquor) from Solutions
thereof.
We, JOSIAH RIGBY WYLDE, MARTIN JOSEPH HAMMILL, and HARRY AUER, all of
the Widnes Alkali Company's Works, Widnes, in the County of Lancaster, Manu-
facturing Chemists, do hereby declare the nature of this invention to be as follows:-
This invention has for its principal object the extraction of the residual chlorate of
potash in the manufacture of that salt by means of chlorine and lime, or magnesia.
It can also be applied to the original liquor before separation of the chlorate of potash
by the existing process, and also is applicable, if desirable, for extracting the-chloride
of calcium, or of magnesium from the mother liquor.
In carrying out our invention, we refrigerate the residual liquors of the ordinary
processes for obtaining chlorate of potash, to from 5 degrees to 10 degrees Centigrade,
whereby a large additional crop of chlorate of potash crystals are precipitated. We
then, if it be desirable, still further refrigerate the liquor when the chloride also
separates as a crystalline powder (apparently a hydrate) and can be separated from
the water by running out and filtering or other means. The mode of refrigeration
we, at present, prefer is by the expansion of cooled compressed air, the same being
passed through pipes in the liquor, or even bubbled through it.
In either case the air can be used methodically, namely, the cold air can be caused
successively to re-act, first, on the nearly completed refrigerated solution, and after-
wards on less and less refrigerated liquor, and thus the refrigerating capacity of the
air be used to the utmost extent. The chloride or hydrated chloride obtained, can be
heated and fused in the usual manner.
Dated this 18th day of October 1888..
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or Appertaining to the Separation of Chlorate of
Potash (and if Desirable the Cloride of Calcium or Magnesium,
or other similar Salt in the Mother Liquor) from Solutions
thereof.
We, JOSIAH RIGBY WYLDE, MARTIN JOSEPH HAMMILL, and HARRY AUER, all of
the Widnes Alkali Company's Works, Widnes, in the County of Lancaster, Manu-
facturing Chemists, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
In the manufacture of potassium chlorate, either by the lime or magnesia process,
there is a considerable quantity of chlorate of potash left in the mother liquors of
the first crystallization, along with chloride of calcium or chloride of magnesium,
which chlorate is practically lost.
We have found that on lowering the temperature of the mother liquor by means
of refrigeration, a considerable additional quantity of chlorate of potash is obtained,
which may be contaminated, if the solution be too much concentrated, with chloride
of calcium or chloride of magnesium.
To prevent this contamination the mother liquors from the lime process ought to
measure not more than about 72 degrees Twaddle, and those from the magnesia process
not more than about 51 degrees Twaddle, at normal temperatures.

page_text: As the mother liquors from the lime process measure generally between 74 and
82 degrees Twaddle, it is obvious that they will either require to be diluted to the
desired degree of concentration, or else, the evaporation of the chlorate liquor stopped
at an earlier stage than usual, so as to obtain mother liquors of the strength required.
Mother liquors from the magnesia process will have to be treated similarly.
With liquors diluted to these specific gravities, namely, 72 degrees Twaddle for
liquors from the lime process, and 51 degrees Twaddle for liquors from the magnesia
process, it is possible to reduce the temperature to about 0 degrees Fahrenheit without
any chloride of calcium or chloride of magnesium crystallizing out.
To carry out our invention we prefer to use the following method:
A tank is provided capable of holding one week's liquors this tank is provided
with a coil of piping for the circulation of the medium, (brine or calcium chloride)
by which the heat is transferred from the mother liquor to the refrigerator. The
refrigerator may be on any known principle.
The chlorate of potash crystallizes out, rapidly at first, and more slowly afterwards,
and the refrigeration is continued as long as there is any substantial decrease in the
quantity of chlorate of potash in solution.
The operation may generally be finished within one week, and after running the
liquor off, the recovered crystals are collected and treated in the ordinary way.
The chloride of calcium or chloride of magnesium contained in the mother liquors
can be obtained, if required, by reducing the temperature of the liquors, from which
the chlorate has been recovered, to a still lower degree, or by refrigerating, in the
first instance, undiluted and preferably highly concentrated liquors to a temperature
at which the bulk of the chloride of calcium or magnesium crystallizes out (in
combination with six molecules of water); the remaining mother liquor may be
afterwards treated, in another vessel, for the recovery of potassium chlorate, substan-
tially as described above.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1st. The application of refrigeration to liquors resulting either from the lime or
magnesia processes of manufacturing potassium chlorate, to obtain an increased
production of potassium chlorate, under the conditions substantially above described.
2nd. The application of refrigeration to mother liquors resulting either from the
lime or magnesia processes of manufacturing potassium chlorate, to obtain chloride of
calcium or chloride of magnesia therefrom.
Dated this 24th day of July 1889.
GEORGE C. DYMOND,
Of 6, Lord Street, Liverpool, Patent Agent for the Applicants.