, and of Baryum
Year: 1887

page_text: of Strontium, and of Baryum.
I, ALEXANDER FELDMANN, chemist, residing at Linden near Hanover, in the
Kingdom of Prussia, do hereby declare the nature of this invention for "IMPROVE-
MENTS IN THE PRODUCTION OF THE FLUORIDES OF MAGNESIUM, OF STRONTIUM AND
OF BARYUM," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention has for its object the production of the fluorides of magnesium, of
strontium and of baryum, and it consists in treating the chloride of magnesium, of
strontium or of baryum, or the double chloride of magnesium and potassium, with
fluoride of calcium and application of heat, and separating the fluoride of magnesium,
of strontium or of baryum, thus obtained, which are insoluble, from the soluble chloride
or chlorides by lixiviation.
The production of the said fluorides may be carried out either in the dry or in the
wet way. In the first case the fluoride of calcium is mixed with anhydrous chloride
of magnesium, or chloride of strontium, or of baryum in excess, the substances
being finely powdered, and the mixture is melted at a red heat. A double
decomposition is thereby brought about, so that, on one hand, chloride of calcium
is formed and on the other hand, fluoride of magnesium, of strontium or of
baryum. After having cooled, the mass obtained is lixivated with water, whereby
the chloride of calcium and the residual chloride of magnesium, of strontium, or
of baryum are dissolved, the substance remaining after repeated washing with
fresh water being the fluoride of magnesium, of strontium, or of baryum.
Instead of the anhydrous chloride of magnesium, which is very expensive, the
double chloride of magnesium and potassium (carnallite) is with advantage
employed, the process remaining, for the rest, the same.
In case the process is to be carried out in the wet way, the powdered fluoride of
calcium is mixed with a concentrated solution of chloride of magnesium, of strontium,
or of baryum in excess and heated until the required double decomposition has taken
place, water being added at intervals to make up for loss by evaporation. The
resulting mass is allowed to cool, whereby it solidifies, and it is thereupon lixivated

page_text: in the same manner as stated above. The magnesium chloride may in this case also
be replaced by the double chloride of magnesium and potassium. If the simple
magnesium chloride is used, which in hydrated and dissolved state is apt to be
decomposed by heat into muriatic acid and magnesia, the mixture must not be raised
materially above the temperature at which the said decomposition begins; but
towards the end of the operation a somewhat greater heat may be applied. In view
of checking this decomposition it is advantageous to add some muriatic acid to the
mixture. Also during the lixivating operation muriatic acid may be used to dissolve
any magnesia that has separated out. If fluoride of calcium should have remained
behind in unaltered state, it may be removed by elutriation from the fluoride of
magnesium, which is much lighter than the former.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed, I declare that what I claim is :
1. The process of mixing calcium fluoride with double chloride of magnesium and
potassium, chloride of strontium, or chloride of baryum, melting the mixture and
lixivating the product, for the purpose of producing fluoride of magnesium, of
strontium, or of baryum, substantially as hereinbefore described.
2. The process of mixing calcium fluoride with chloride of magnesium, double
chloride of magnesium and potassium, chloride of strontium, or chloride of baryum,
dissolved in water, heating the mixture and lixivating the product, for the purpose
of producing fluoride of magnesium, of strontium, or of baryum, substantially as
specified.
T
1000