IMPROVEMENTS IN THE MANUFACTURE OF THE SALTS, CARBONATES, AND HYDRATES OF BARYTA AND STRONTIA, AND ALSO FOR IMPROVED MODES OF MAKING BARYTA AND STRONTIA CAUSTIC
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Edward Thomas Hughes at the
Office of the Commissioners of Patents, with his Petition, on the
16th September 1872.-A communication from abroad by Louis
Gustave Ghilain Daudenart and Edmond Verbert, of 31, Rue du
Progrès, Schaerbeck, Brussels.
I, EDWARD THOMAS HUGHES, of the Firm of Hughes and Son,
Patent Agents, 123, Chancery Lane, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF THE SALTS, CARBONATES, AND HYDRATES OF BARYTA AND STRONTIA, AND ALSO
FOR IMPROVED MODES OF MAKING BARYTA AND STRONTIA CAUSTIC," a
munication to me from abroad by Louis Gustave Ghilain Daudenart
and Edmond Verbert, of 34, Rue du Progrès, Schaerbeek, Brussels, to
be as follows :—
com-
In order to produce the carbonates of baryta and strontia according
to our process we take alkaline earthly chlorides not only because they are
very soluble and that suphates of bartya and struntia are obtained from
them with facility and economy, but also that by means of our process

page_text: we obtain free hydrochloric acid at the same time that the carbonates
of a alkaline earths are produced.
The reactions which take place are explained by the following
equations made with regard to the obtaining of carbonate of baryta, and
the equations are the same for carbonate strontia, it being only necessary 5
to take chloride of strontium instead of chloride of barium.
The chlorides of barium and strontium whether obtained by one of
the following oridinary methods:-First, by the action of hydrochloric
acid on the carbonates of baryta and strontia in their material state.
Secondly, by the action of the same acid on the sulphurets of barium
and strontium procured by the decomposition of the sulphates of these
basis by carbon. Thirdly, by the reciprocal action indicated by
Monsieur Kuhlmann between the sulphates of bartya or strontia carbon
and the chloride of manganese or by any other method by which they
are dissolved in water to 12 or 15 degrees Baume.
The solution thus obtained, whether the chloride of barium or the
chloride of strontium, is mixed with hydrate of magnesia in any suitable
apparatus which can be afterwards closed. This mixture is kept in
continual agitation in the closed apparatus and subjected to the action of
a current of carbonic acid, which gas is absorbed by the magnesia forming
a carbonate of this base. In principle the carbonate of magnesia decom-
poses the alkaline earthly chlorides, but the employment of an excess of
carbonic acid causes the decomposition to be more rapid and at the same
time the carbonates of the alkaline earths are obtained, especially those
of baryta and strontia, free from carbonate of magnesia, a result that
cannot be obtained by the mixture of the carbonate of magnesia only.
This carbonate dissolves in water assisted by an excess of carbonic
acid, and thus a bicarbonate of magnesia is formed, and besides this a
double decomposition rapidly takes place between the alkaline carthly
chlorides and the bicarbonate of magnesia, carbonate of baryta is pre-
cipitated, the carbonic acid is regenerated, and the liquor holds in solution
of chloride of magnesium as expressed by the following notation :—
O,lBax(CO*)MgO×4qCO BaOxC1MẸ, CÓ Aq.

page_text: Carbonate of magnesia being but little less soluble in carbonate acid, or
in other words the solubility in water of the bicarbonate of magnesia being
feeble it was conceived that the current of carbonic acid should be
made to pass for a much longer time than would be required for the
simple carbonation of magnesia.
It is evident that the carbonation can be effected in any special or
distinct apparatus, and variations of minor importance may be made in
the manipulation, but the process before described is preferred on account
of its simplicity.
In practice the treatment of the alkaline earthly chlorides by magnesia
and carbonic acid should consist of two operations. In the first, the
magnesia is in excess which gives when the reaction is terminated a
liquor containing exclusively chloride of magnesium, which is decanted
and a precipitate obtained consisting of a carbonate of the alkaline
earth and the magnesia employed in excess in a carbonated state. In
the second operation an excess of alkaline earthly chloride is found on
the precipitate that is a quantity of the chloride equal. to that pre-
viously used, augmented by a little in addition to what is necessary for
the neutralization of the excess of the carbonate of magnesia. By the
action of the carbonic and the excess of the carbonate of magnesia is
transformed into chloride of magnesium, and is replaced in the prece-
pitate by an equivalent quantity of carbonate alkaline earth, the final
result being being carbonate of baryta strontia, which is obtained in a
pure state after a series of washings.
The liquor after this second operation is a mixture of chloride of
magnesium and of alkaline earthey chloride; the latter being in excess
should be again used, as it is superior to that employed in the first
operation, and by means of known reagents and tests it is to be ascer-
tained, first, that the liquor of the alkaline carthey chloride employed
the first time contains only chloride of magnesium when the reaction
has terminated; and, secondly, that the precipitate after the second
operation washed and dissolved in hydrochloric and does not contain
any magnesia.
The liquors which only contain chloride of magnesium are concen-
trated by evaporating to 44 or more degrees Baumé, and are then
passed into the crystallizers, or if allowed to cool they become hard
massers which are broken in pieces to remove them, and as will be seen

page_text: the hydrochloric acid revivifics the magnesia according to the following
equation,―
C, 1Mg×HO=C1H× Mg, O
It is of importance to remark that the hydrated chloride of magnesium
calcind at a low red heat in a reverbatory furnace or in crucibles is
not completely decomposed, one-fifth cscapes decomposition by the simple
disengagement of a part of the water it contains, besides all the magnesia
formed and submitted in this operation to a heat above 300 degrees
centigrade is when cold in an unfavorable condition for absorbing
carbonic acid, and it is hydrated with such slowness as to be incom- 1
patible with a rapid revification of the carbonate of magnesia, and it
is upon the revification that the whole of our manufacture is based.
Hydrated chloride of magnesium submitted to the action of a current
of steam superheated to about 300 degrees centigrade without pressure
becomes completely decomposed as is in the condition to be rapidly 1
hydrated and carbonated.
To manufacture caustre baryta and strontia from their carbonates
by our process we mix the carbonate of baryta or strontia with carbon
or chalk, and heat the mixture, whether subjected to the action of
superheated steam or not, in a regenerating or reverbatory furnace, a
which process is applicable not only to the carbonates of bartya and
strontia manufactured as before described, but also to the carbonate of
bartya and strontia manufactured as before described, but also to the
carbonates of baryta and strontia in their natural state or produced in
any other water, and we also employ the furnaces for the decomposition 2
of all salts that require a high temperature, especially the sulphates of
bartya and strontia mixed with carbon.
By these means we obtain such a temperature that the carbonates of
bartya and strontia, whether mixed with carbon or submitted to the action
of superheated steam, are rapidly decomposed with great facility and
therefore economically, and in our final Specification we will describe
other developments and details arising from the practical working of
the process.