Improved Process for the Production of Strontium Carbonate.
Year: 1899

page_text: Date of Application, 19th Dec., 1899-Accepted, 3rd Mar., 1900
COMPLETE SPECIFICATION.
Improved Process for the Production of Strontium Carbonate.
I, ALBERT WENCK, of No. 2, Frankestrasse, Magdeburg, in the German Empire,
Merchant, 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:-
This invention relates to an improved process for the production of strontium
carbonate from strontium sulphate and other strontium salts; this process is also
applicable to the production of strontium carbonate from celestine (the natural
mineral form of strontium sulphate) and from the residual products obtained
in the manufacture of sugar by the strontia process.
In proceeding according to the processes hitherto employed with this object, it
has not been possible by the use of equivalent amounts of alkaline carbonate to
convert strontium sulphate quantitatively into strontium carbonate. In fact, even
the double equivalent amount of alkaline carbonate has been found insufficient
in the ordinary conditions of working, to effect a quantitative conversion of
strontium sulphate into strontium carbonate.
Now this object, viz., the quantitative conversion of strontium sulphate into
strontium carbonate, is effected by my improved process which consists in treating
strontium sulphate, or other suitable strontium salt, with equivalent amounts of
alkaline carbonate at a pressure exceeding that of the atmosphere, and at a
corresponding higher temperature, under the simultaneous action of carbonic
acid.
My improved process greatly reduces the cost of producing strontium carbonate
from celestine and other strontium salts.
For the purpose of carrying out my improved process in a practical manner I
employ a closed jacketted vessel provided with a stirring or agitating device and
capable of withstanding internal pressure. Into this vessel I place the strontium
sulphate (celestine) or other strontium salt in a condition of fine powder, and
I stir up the salt well with water. The equivalent amount of alkaline carbonate,
preferably sodium carbonate, is introduced into the vessel which is then closed.
The contents of the vessel are then super-saturated with carbonic acid. Then
steam at a pressure of about eight atmospheres, is passed into the jacket of the
vessel so as to raise the temperature of the contents of the vessel to about 175
degress Celsius.
By these means a complete quantitative conversion of the strontium sulphate
or other strontium salt employed, into strontium carbonate is effected.
The strontium carbonate can then be separated from the dissolved sodium
sulphate by any suitable means.
An alternative mode of carrying out my improved process consists in first
introducing into the empty vessel a solution of the carbonate of an alkali, then
by the introduction of carbonic acid converting the carbonate solution into a solu-
tion of an equivalent amount of the bicarbonate of the alkali, and then intro-
ducing the strontium sulphate or other strontium salt employed into the same
with simultaneous stirring of the contents of the vessel which is then heated by
steam as above set forth.

page_text: 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:-
The improved process for the production of strontium carbonate from strontium
sulphate and other strontium salts, which consists in treating strontium sulphate
or other strontium salt with a carbonate of an alkali and carbonic acid, under
pressure and with heat, substantially as herein before described.
Dated this 19th day of December 1899.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.