IMPROVEMENTS IN THE MANU- FACTURE OF HYPOSULPHATES AND SULPHATES OF ALKALIES
Year: 1885

page_text: I, HENRY BOLLMANN CONDY, of Condy's Chemical Works, Battersea, London,
do hereby declare the nature of said invention for IMPROVEMENTS IN THE MANU-
FACTURE OF HYPOSULPHATES AND SULPHATES OF ALKALIES, to be as follows:-
These improvements consist in the conversion of the more soluble alkaline salts,
such as chloride, nitrate, or acetate of soda or potash, into hyposulphates of any
or either of these alkalies, by treating them with hyposulphate of manganese in
aqueous solution.
Experiments having led me to the conclusion that the hyposulphates of soda and
potash possess advantages, as medicinal agents, over sulphates, such as those of soda,
potash or magnesia, it becomes important that a practical method of obtaining these
salts, should be devised-And this importance is increased by the circumstance that
I have found the most practical way of making the purest kind of sulphate of soda
or potash (either when required as simple sulphates, or for subsequent conversion
into carbonates) is, first of all, to prepare hyposulphate of soda or potash by my
present process, and then by heating this salt at a low red heat, to drive off
the sulphurous acid (which can be re-utilised) and thereby obtain a nearly pure
sulphate.

page_text: Sulphates of Alkalies.
I, HENRY BOLLMANN CONDY, of Condy's Chemical Works, Battersea, London,
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:-
These improvements consist in the conversion of the more soluble alkaline salts,
such as chloride, nitrate, or acetate of sodium or potassium into byposulphates of
either of these alkalies by treating them with hyposulphate of manganese in
aqueous solution.
Experiments having led me to the conclusion that the hyposulphates of soda and
potash possess advantages, as medicinal agents, over sulphates, such as those of soda,
potash or magnesia, it becomes important that a practical method of obtaining these
salts, should be devised-and this importance is increased by the circumstance that
I have found the most practical way of making the purest kind of sulphate of soda
or potash (either when required as simple sulphates, or for subsequent conversion
into carbonates) is, first of all, to prepare hyposulphate of soda or potash by my
present process, and then by heating this salt at a low red heat, to drive off the
sulphurous acid (which can be re-utilized) and thereby obtain a nearly pure
sulphate.
The present process depends for its success on the small degree of solubility of
hyposulphate of potash or soda in the presence of a strong solution of chloride,
nitrate or acetate of manganese. The conversion of chloride of sodium or potassium
into hyposulphate of soda or potash is the more important object scientifically and
commercially, and the reaction involved in the production of a hyposulphate is
similar in the case of nitrate or acetate of soda or potash, the main difference being
that the mother liquor from which the hyposulphate is precipitated or crystallized
contains nitrate of manganese when alkaline nitrates are treated and acetate of
manganese when alkaline acetates are treated with hyposulphate of manganese.
I will now proceed to illustrate the nature of my process by a description of the
treatment of chloride of sodium for the production of hyposulphate of soda.
I make a solution of hyposulphate of manganese by the known process of treating
sulphurous acid in solution with peroxide of manganese, and I concentrate this
solution by evaporation till it attains the specific gravity of 1.50. Of this solution
I take 100 lbs, and I make a solution of common salt consisting of 25 lbs of chloride
of sodium in 67 lbs of water. I warm the solution of hyposulphate of manganese
to about 150° Fahrenheit, and I heat the solution of chloride of sodium to
about 200°. I then add the former to the latter, and allow the product to cool
and crystallize.
Nearly the whole of the soda contained in the chloride of sodium is obtained as
hyposulphate of soda, the rest amounting to about 6 per cent may remain in solution
at ordinary temperatures. This may be recovered by evaporating the mother
liquor, which consists principally of chloride of manganese, to of its volume, and
allowing it to cool, when the small quantity of hyposulphate of soda will crystallize

page_text: out. Another method by which I accomplish my object is by adding to the cold
solution of chloride of sodium the cold solution of hyposulphate of manganese,
both made as before described. I do not limit myself to the exact proportions or
strengths or temperatures, for I find in practice that an excess of either salt does
not materially interfere with the reaction, and the hyposulphate of manganese may
be used as a solution of half the strength named, and therefore double the volume,
by dissolving in it the dry chloride of sodium. The hyposulphate of soda should
be drained and washed in a hydro-extractor or otherwise, or if required it can be
re-crystallized. The mother liquor, consisting essentially of chloride of manganese,
can be used as a precipitating and antiseptic agent, or be employed for the recovery
of the peroxide of manganese by the well known plan of precipitating protoxide of
manganese by lime, and its subsequent peroxidation by atmospheric air.
It is unnecessary to describe the method pursued in the decomposition of chloride
of potassium, or nitrate or acetate of potash or soda, further than to state that it
is desirable to use these substances or either of them as nearly as possible in their
chemical equivalents, that instead of 25 lbs of chloride of sodium I would use 32 lbs
of chloride of potassium, or 43 lbs of nitrate of potash, or 36 lbs of nitrate of
soda, or 42 lbs of acetate of potash or 58 lbs of crystallized acetate of soda. When
nitrate or acetate of soda is employed, the mother liquor, after the production and
separation of the alkaline hyposulphate, will consist essentially of nitrate or acetate
of manganese, which may be employed for the recovery of the peroxide of man-
ganese by precipitation and atmospheric oxidation, or used for any other purpose
for which those salts may be required. For the subsequent conversion of hypo-
sulphate of soda or potash into sulphate of soda or potash, all that is necessary is
to dry them and heat them to redness.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. The production of hyposulphates of alkalies, by treating soluble alkaline
salts, such as chloride, nitrate, or acetate of sodium or potassium, with hyposulphate
of manganese.
2. The production of hyposulphates of alkalies and subsequent conversion of the
same into sulphates, in the manner substantially as described.