Carbonate of Strontium or of Barium.
Year: 1885

page_text: Carbonate of Strontium or of Barium.;
I, EUGENE FRANÇOIS TRACHSEL, of N° 45 Miranda Road, Holloway, in the
County of Middlesex, Chemist, do hereby declare the nature of my invention for
"AN IMPROVED METHOD OR PROCESS OF PRODUCING HYDRATE OR CARBONATE OF
STRONTIUM OR OF BARIUM" to be as follows:-
The object of my invention is the conversion of sulphate of strontium or of
barium into hydrate or carbonate of these bases. I obtain this result by means of
caustic soda or potash or carbonate of sodium or potassium, a suitable quantity of
which I repeatedly use and reconvert throughout the process.
I calcine the sulphate of strontium or of barium (alone or mixed with coal or
other carbonaceous matter) in a reducing flame to convert the sulphate into
sulphide.
I then lixiviate this sulphide preferably with boiling water, and treat the
solution of the sulphide as follows viz:
•
In the case of sulphide of strontium I prefer that the liquor should cool down
until it deposits about one half of its strontia as strontium hydroxide according to
the following equation
2 Sr S + 2 H2O = Sr (HS), + Sr (OH),.
The hydrate of strontium crystallizes out with 8 molecules of water of
crystallization; the crystals, after washing and purification, are ready for use or
sale. The mother liquor is treated as follows; that is to say,
I treat the solution of sulphydrate of strontium with caustic alkali and obtain
hydrate of strontium and sulphide or sulphydrate of sodium in solution as will
appear by the following reactions
Sr (HS), +2 Na OH
or Sr (HS), +4 Na OH
=
Sr (OH), 2 Na HS,
==== Sr (OH)2 + 2 Na, S + 2 H, O.
I sometimes treat the solution of sulphide of strontium directly with caustic
alkali and obtain a deposit of hydrate of strontium and a solution of alkaline
sulphide, as follows
Sr S2 Na OH
=
Sr (OH), + Na, S.
1. half the amount of it all.
L

page_text: The hydrate of strontium crystallizes out on cooling and I boil down the sulphide
of sodium because I have found that concentrated solutions of the sulphides are the
most easily converted by carbonic acid; that is to say, the greater the strength of
such solutions the more easily are they acted upon by carbonic acid.
If I wish to obtain a solution of carbonate of sodium, I boil the sulphide down
to about twenty (20) degrees Twaddell, but if I wish to obtain crystallized
carbonate of sodium I concentrate the sulphide liquor to obtain thirty (30) degrees
Twaddell.
Taking a solution of sulphide or sulphydrate of sodium of say twenty (20) degrees
Twaddell obtained as above described, I treat this solution in any suitable apparatus
by forcing or drawing through it gases rich in carbonic acid, and I.stop the action
of the gases when about half of the sulphide is converted. Its conversion takes
about 24 or 30 hours, more or less, according to the strength and the quantity of
the gases; the liquor then consisting of carbonate of sodium and sulphide of
sodium is treated with caustic lime to convert the carbonate of sodium contained
in it, into caustic soda. The sulphuretted hydrogen given off by the treatment of
the sulphide with carbonic acid is disposed of in any suitable manner.
The liquor,
after treatment with caustic lime, is again used for precipitating hydrate of
strontium. In the case of a stronger solution (say 30° Twaddell) the carbonate of
sodium formed crystallizes out during the treatment with carbonic acid, and
prefer separating the crystals from the mother liquor for further use after
causticising, but I may leave the crystals in the liquor and heat the whole with
caustic lime.
If hydrate of barium is to be obtained I use the same process but I prefer to
treat the monosulphide of barium direct as shown by the following reactions.
Ba S + Na OH + H, O = Ba (OH), + Na HS
or Ba S2 Na OH: = Ba (OH) + Na, S.
"
To obtain carbonate of strontium I treat the solution of sulphide or bydrosulphide
of strontium with carbonate of soda, thus
Sr S + Na, CO, = Sr 00, + Na, S
or 'Sr (SH), + Na₂ CO,
=
Sr CO, 2 Na HS
and the solution of sulphide or sulph-hydrate of sodium is converted into carbonato
as above described. But in this case the causticising with lime is not necessary.
Carbonate of barium is obtained in a similar manner, the soda being recovered
in the same way.
Instead of using carbonate of sodium or caustic soda in the above processes, I
may use carbonate of potash or caustic potash, with the difference that the
carbonate of potash crystallizes out with difficulty and therefore if crystals are to
be obtained the solutions of sulphide of potassium have to be much stronger than
the solutions of sulphide of sodium.
It is obvious that with the same quantity of alkali, I may obtain at one time
hydrate of strontium or of barium, and at another time carbonate of strontium or
of barium, using the alkali first as caustic alkali and then as carbonate, or vice
versa.
Instead of using the sulphate of strontium or of barium obtained as above
specified, I may convert sulphides of strontium or of barium, obtained by other
processes, or as bye-products, into hydrate or carbonate by the process above
described.

page_text: Carbonate of Strontium or of Barium.
I, EUGENE FRANÇOIS TRACHSEL, of 45 Miranda Road, Holloway in the County
of Middlesex, Chemist, 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:—
The object of my invention is the conversion of sulphate of strontium or of
barium into hydrate or carbonate of these bases. I obtain this result by means of
caustic soda or potash or carbonate of sodium or of potassium, a suitable quantity
of which I repeatedly use and reconvert throughout the process.
I calcine the sulphate of strontium or of barium (alone or mixed with coal or
other carbonaceous matter) in a reducing flame to convert the sulphate into
sulphide.
I then lixiviate this sulphide, preferably with boiling water, and treat the
solution of the sulphide as follows, that is to say :—
To obtain hydrate of strontium, I, in some instances, cool down the sulphide
solution until it deposits about one half of its strontia in the form of strontium
hydroxide according to the following equation
2 Sr S + 2 H₂ O = Sr (HS), + Sr (OH),
The hydrate of strontium crystallizes out with eight (8) molecules of water of
crystallization; the crystals, after washing and purification, are ready for use or
sale. The mother-liquor, which is a solution of sulphydrate of strontium, I treat
with caustic alkali and obtain hydrate of strontium and sulphide or sulphydrate of
sodium in solution, as will appear by the following reactions:—
Sr (HS), 2 Na OH
=
Sr (OH) 2 Na HS,
or Sr (HS), + 4 Na OH = Sr (OH), + 2 Nª S + 2 H₂ O.
:
I find it more convenient, however, to treat the solution of sulphide of strontium
directly (that is to say, while hot) with caustic alkali. I thus obtain a deposit of
hydrate of strontium and a solution of alkaline sulphide as follows:-
Or,
Sr S2 Na OH =
Sr (OH) + Na S,
by using only half the amount of caustic alkali, thus:—
Sr S + NaOH + H2O = Sr (OH), + Na HS.
The hydrate of strontium crystallizes out partly during treatment and partly on
cooling, and I convert the sulphide of sodium into carbonate of sodium by means of
carbonic acid. I prefer to boil down the sulphide of sodium, because I have found
that concentrated solutions of the sulphides are the most easily converted by
carbonic acid, that is to say, the greater the strength of such solutions the more.

page_text: If I wish to obtain a solution of carbonate of sodium, I boil the sulphide down to
about twenty (20) degrees Twaddell, but if I wish to obtain crystallized carbonate
of sodium, I concentrate the sulphide liquor to about thirty (30) degrees Twaddell.
After boiling down the liquor, I allow it to cool and obtain another quantity of
crystals of hydrate of strontium, this hydrate being less soluble in a concentrated
solution of sulphide of sodium than in a weak solution. I then proceed to the
conversion of the sulphide of sodium into carbonate of sodium.
Taking a solution of sulphide or sulphydrate of sodium of say twenty (20) degrees
Twaddell obtained as above described, I treat this solution in any suitable apparatus
by forcing or drawing through it gases rich in carbonic acid and I stop the action
of the gases when about half of the sulphide is converted. I may, however, carry
on the conversion of the sulphide of sodium further than one half, or I may convert
all the sulphide into carbonate, but I find it more profitable to convert only about one
half or three-fourths of the sulphide of sodium into carbonate, as the last part of
this process of conversion takes considerably more time than the first part thereof,
and therefore renders the operation less profitable. This conversion takes from
about 24 to about 30 hours more or less according to the strength and the quantity of
the gases; the liquor then consisting of carbonate of sodium and sulphide of sodium
is treated with caustic lime to convert the carbonate of sodium which it contains
into caustic soda. The sulphuretted hydrogen given off by the treatment of the
sulphide with carbonic acid is disposed of in any suitable manner. The liquor, after
treatment with caustic lime, is again used for precipitating hydrate of strontium,
the sulphide of sodium in the liquor not affecting its action.
In the case of a stronger solution (say 30° Twaddell), the carbonate of sodium
formed crystallizes out during the treatment with carbonic acid, and I prefer
separating the crystals from the mother-liquor for further use after causticising, but
I may leave the crystals in the liquor and heat the whole with caustic lime.
If hydrate of barium is to be obtained, I use the same process, but I prefer to
treat the monosulphide of barium directly (that is to say, while hot), as shown by
the following re-actions.

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 method or process for the production of hydrate or carbonate of
strontium or of barium from sulphate of strontium or of barium by means of caustic
soda or potash or carbonate of sodium or of potassium, which are repeatedly used
and reconverted or recovered, substantially as, and for the purpose, specified.