IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF STRONTIA "
Year: 1883

page_text: LETTERS PATENT to William Augustus Rowell of Jesmond Gardens Newcastle
on Tyne Chemical Manager for an Invention of " IMPROVEMENTS IN THE
MANUFACTURE OF CARBONATE OF STRONTIA "
PROVISIONAL SPECIFICATION left by the said William Augustus Rowell at
the Office of the Commissioners of Patents on the 14th April 1883.
"
WILLIAM AUGUSTUS ROWELL of Jesmond Gardens Newcastle on Tyne Chemical
Manager "IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF STRONTIA
This Invention has for its object Improvements in the Manufacture of Carbonate
of Strontia
Sulphate of Strontium or Celestine is treated in contact with Coal so as to form
Sulphide of Strontium in the usual manner
A strong solution of this Sulphide in hot water is obtained and the Coal ashos
and unreduced sulphate and other insoluble impurities separated by settling or
filtration
The clear Solution of soluble Strontium salts is transferred to a vessel preferably
of iron made air tight and provided with a pipe to convey away the gases given
off in the ensuing process. This vessel is provided with steam jacketing or other
suitable means for heating its contents as also with apparatus for stirring them.
The soluble strontium salts obtained from the sulphide of strontium as above, now
in solution are while in the vessel described, treated with a strong solution of
Magnesium Chloride.
This is best done by bringing the strontium solution to a boil and gradually
adding the Magnesium Chloride solution. The magnesium Chloride acting on the
sulphides of Strontium in presence of water drives off the sulphur as Sulphuretted
hydrogen leaving the strontium as Chloride of Strontium and Magnesium as an
oxide of magnesia suspended in the solution of Chloride of Strontium when an
excess of Magnesium Chloride has been added and the liquid kept for some time
at a boil under agitation to expel dissolved sulphuretted bydrogen this part of the
process is complete The sulphuretted hydrogen evolved can be used for making
sulphuric acid.

page_text: The solution of Chloride of Strontium and the suspended Magnesia obtained as
above are together run into another Vessel in which they are treated with Carbonic
acid in any form preferably under pressure
The carbonic acid acts in such a manner as to convert the Strontium Chloride
and Magnesia respectively into Strontium Carbonate which is precipitated as such
and Magnesium Chloride which remains in solution.
The mixed Magnesium Chloride solution and precipitated Carbonate of Strontium
are thoroughly separated by means of a filter press. The Magnesium Chloride
solution is concentrated and used again. The Strontium carbonate which is in
cakes in the filterpress is taken out and dried, when it is fit for making salts of
Strontia or for Sale the strong hot solution of sulphide of strontium etc is allowed
to cool, when it deposits crystals of hydrate of Strontium
When this has occurred to an extent which leaves the sulphur and Strontium
present in the solution approximately in the proportions to form Sulphydrate of
Strontium the solution is separated from the hydrate crystals and treated as above
with Magnesium Chloride as in paragraph 3 and Carbonic acid as in paragraph 4
yielding Carbonate of Strontia, Sulphuretted hydrogen and Magnesium Chloride

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Augustus Rowell in the Great Seal Patent Office on the
13th October 1883.
WILLIAM AUGUSTUS ROWELL of Jesmond Gardens Newcastle-on-Tyne Chemical
Manager “ImproveMENTS IN THE MANUFACTURE OF CARBONATE OF STRONTIA
"
This invention has for its object improvements in the manufacture of carbonate
of strontia.
Sulphate of strontium or celestine is heated in contact with coal so as to form
sulphide of strontium in the usual manner.
A strong solution of this sulphide in hot water is obtained and the coal ashes
and unreduced sulphate and other insoluble impurities separated by settling or
filtration,
The clear solution of soluble strontium salts is transferred to a vessel preferably
of iron, made air tight, and provided with a pipo to convey away the gases given
off in the ensuing process. This vessel is provided with steam jacketing or other
suitable means for heating its contents, as also with apparatus for stirring them.
The soluble strontium salts obtained from the sulphide of strontium as above, now
in solution are, while in the vessel described, treated with a strong solution of
magnesium chloride. This is best done by bringing the strontium solution to a
boil and gradually adding the magnesium chloride solution. The magnesium
chloride acting on the sulphides of strontium in prosence of water drives off the
sulphur as sulphuretted hydrogen leaving the strontium as chloride of strontium
and magnesium as an oxide of magnesia suspended in the solution of chloride of
strontium. When an excess of magnesium chloride has been added and the liquid
kept for some time at a boil under agitation to expel dissolved sulphuretted hydrogen
this part of the process is complete. The sulphuretted hydrogen evolved can be
used for making sulphuric acid.
The solution of chloride of strontium and the suspended magnesia obtained
as above are together run into another vessel in which they are treated with
carbonic acid in any form preferably under pressure.
The carbonic acid acts in such a manner as to convert the strontium chloride and
magnesia respectively into strontium carbonate which is precipitated as such, and
magnesium chloride which remains in solution.
The mixed magnesium chloride solution and precipitated carbonate of strontium
are thoroughly separated by means of a filter press. The magnesium chloride
solution is concentrated and used again. The strontium carbonate which is in
cakes in the filter press is taken out and dried, when it is fit for making salts of
strontia or for sale.
The process may be varied by allowing the solution containing sulphide of
strontiuin to cool before treating it with magnesium chloride. Crystals of hydrate
of strontia are then deposited, they are then removed and the liquor is then treated
in the manner above described.
What I claim is the manufacture of carbonate of strontia by the combined
processes herein described, that is to say (1) the conversion of the sulphate into
sulphide by heating it with carbonaceous matter (2) the conversion of the sulphide
into chloride by means of chloride of magnesium and (3) the conversion of the

page_text: chloride into carbonate by the action of carbonic acid in presence of magnesia
substantially as described
In witness whereof I the said William Augustus Rowell have hereunto set
my hand and seal this 12th day of October in the year of our Lord One thousand
eight hundred and eighty three