of Potassium and Hydrate of Strontium or of Barium.
Year: 1886

page_text: Date of Application, 10th Mar., 1886.
Complete Left, 9th Dec., 1886.
Complete Accepted, 11th Jan., 1887.
of Potassium and Hydrate of Strontium or of Barium.
I, EUGÈNE FRANÇOIS TRACHSEL, of 45 Miranda Road, Upper Holloway, in the
County of Middlesex, Chemist, do hereby declare the nature of this invention to be as
follows:-
In the well known "Leblanc" process, a large proportion of the sulphur used in
the conversion of the chloride of sodium into carbonate of sodium is lost, even when
known or existing processes for the recovery of the sulphur are resorted to. Morcover
considerable annoyance and inconvenience are caused by the unavoidable soda-waste
in the "Leblanc" process.
29"
My invention is designed to obviate these defects or inconveniences, and to provide
for the recovery of most of the sulphur as such, (with scarcely any inherent cost),
or for the use of the same for the making of the sulphuric acid required in the process.
The waste in my process is very small and is entirely harmless, it being only some
undecomposed sulphate of strontium or of barium mixed with the ashes of coal,
In carrying my invention into practice, I proceed as follows, viz. :-
I calcine an intimate mixture of sulphate of sodium and sulphate of strontium, or of
barium, and coal or other like carbonaceous matter in suitable proportions for the
reduction of the sulphates. I prefer to do this in a so-called "plus pressure furnace"
or in a common reverberatory furnace, and I lixiviate with hot water, the resulting
product which is a mixture of sulphide of sodium, with sulphide of strontium or of
barium, and with the ashes of the coal; I thus obtain a solution of sulphide of sodium
and sulphide of strontium or of barium.
This solution on cooling deposits (if sufficiently strong) most of its strontia or baryta
in the form of hydrate of strontium or of barium, according to the equation.
Tro
VOID
in the case of strontium, and
Nao S Ba S+ 2 H₂O
-
2 (Na HS) + Ba (OH)2
in the case of barium. This reaction of the sulphide of sodium upon the sulphide of
strontium or of barium is an important and essential feature of my invention, as it is
by this reaction that I am enabled to make my process commercially successful.

page_text: The hydrate of strontium or of barium is a valuable and readily saleable article,
which can easily be separated from the mother-liquor consisting of sulphydrate of
sodium. The mother-liquor is then boiled down, and, on cooling, deposits nearly all
the strontia or baryta still contained in it. I thus obtain a strong solution of sulp-
hydrate of sodium, which I subject to the action of carbonic acid by drawing or forcing
through it carbonic acid gas, or gases, more or less rich in carbonic acid. Strong
solutions of sulphydrate of sodium are readily acted upon by carbonic acid, the
reaction being as follows:-
2 Na HS + CO2 + H2O = Na, CO3 + 2 H₂S.
The small quantity of strontia or baryta still left in the liquor separates out as
carbonate of strontium or of barium during the carbonating process.
If the solutions are of a strength of about 30° Twaddell or more, which will depend upon
the previous boiling down, the soda crystallizes out as carbonate with five (5) molecules
of water of crystallization, but, if the solutions are weaker than say 20° Twaddell,
common soda crystals are obtained; or, if very weak solutions are used, no crystalli-
zation takes place. I prefer, however, to use the solution of sulphydrate of sodium as
strong as possible, and, in this case, I separate the crystals of carbonate of soda from
the remaining liquor and make the soda crystals ready for the market in the ordinary
manner, whilst the weak liquor from which these crystals are obtained is boiled down,
and, if not fully converted into carbonate, is returned into the carbonating apparatus.
The sulphuretted hydrogen given off during the carbonating process is easily converted
into sulphurous acid by passing it through a "Claus" kiln, and 'the sulphurous acid
can be used for making sulphuric acid. If the sulphuretted hydrogen is not mixed
with too great a proportion of oxygen, which depends on the composition of the gases
used for carbonating, it can readily be converted into sulphur by passing it through a
"Claus" kili, or by some other suitable process, thus not only recovering the sulphur
from the sulphate of sodium but also the sulphur from the sulphate-of-strontium used
in the process.
Instead of the sulphate of sodium, I sometimes use, in my process, sulphate of
potassium, which acts in the same manner as the sulphate of sodium.

page_text: An Improved Process for the Production of Carbonate of Sodium or
of Potassium and Hydrate of Strontium or of Barium.
1, EUGENE FRANÇOIS TRACHSEL, of 45 Miranda Road, Upper 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 :-
In the well-known "Leblanc" process, a large proportion of the sulphur used in the
conversion of the chloride of sodium into carbonate of sodium, is lost, even when
known or existing processes for the recovery of the sulphur are resorted to. Moreover
considerable annoyance and inconvenience are caused by the unavoidable soda-waste
in the "Leblanc " process.
My invention is partly designed to obviate these defects or inconveniences, and to
provide for the recovery of most of the sulphur as such with scarcely any inherent
cost, or for the use of the same for the making of the sulphuric acid required in the
production of the sulphate of sodium to be used in my process. The waste, in my
process, is very small and is entirely harmless, it being only some undecomposed
sulphate of strontium or of barium mixed with the ashes of coal.
In carrying my invention into practice I proceed as follows, that is to say
I calcine an intimate mixture of sulphate of sodium and sulphate of strontium or of
barium and coal or like carbonaceous inatter in suitable proportions for the reduction
of the sulphates. I have obtained good results. by using the following propor-
tions, viz. :-
9cwt. of sulphate of sodium,
10
cwt. of sulphate of strontium,
cwt. of coal,
8
but the proportions may be varied within very wide limits. I prefer to effect the
reduction in a so-called "plus pressure" furnace, or in a common reverberatory furnace.
The resulting product is a mixture of sulphide of sodium with sulphide of strontium or
of barium and undecomposed sulphate of strontium or of barium (if the decomposition
has not been carried far enough to decompose the whole of such sulphate) together
with the ashes of the coal. I lixiviate this product (after granulation or breaking up
thereof if necessary) with hot or warın water, and thus obtain a solution of sulphide of
sodium and sulphide of strontium or of barium.
This solution on cooling deposits (if sufficiently strong) most of its strontia or baryta
in the form of hydrate of strontium or of barium according to the equation.
Na, S+ Sr S + 2 H₂O 2 (Na HS) + Sr (OH)2
in the case of strontium, and
Na₂ S+ Ba S + 2 H₂O = 2 (Na HS) + Ba (OH)»
in the case of barium.
This reaction of the sulphide of sodium upon the sulphide of strontium or of barium
is an important and essential feature of my invention, as it is by this reaction that I
am enabled to make my proces commercially sunnantil

page_text: In carrying on my process, I have found that, in some cases, especially if the
mixture has not been sufficiently calcined, the sulphate of strontium is only partially
reduced to sulphide, and the consequence is that, besides sulphydrate of sodium, there
is a proportion of sulphide of sodium left in the liquor. It is obvious that this sulphide
of sodium, or sulphide of sodium obtained by other processes, can be used to decompose
sulphide or sulphydrate of strontium according to the above mentioned reaction, and
that the sulphide of strontium or sulphydrate of strontium can be obtained either from
the residue of undecomposed sulphate of strontium from a foriner operation, or by the
reduction of a fresh quantity of sulphate of strontium, without the admixture of
sulphate of sodium or with only a small quantity of sulphate of sodium.
The sulphydrate of strontium can be easily obtained by cooling a hot and concen-
'trated solution of sulphide of strontium as mentioned in the specification of former
Letters Patent dated 11th June A.D. 1885, No. 7136, and the action of the sulphide
of sodium upon the sulphydrate of strontium would then be expressed by the following
equation :--
2 Na, S Sr (HS), + 2 H₂O =4 (NaHS) + Sr (OH)2
The hydrate of strontium or of barium is a valuable and readily saleable article,
'which can easily be separated from the mother-liquor consisting of sulphydrate of
sodium. The mother-liquor is then boiled down and, on cooling, deposits nearly all
the strontia or baryta still contained in it. I thus obtain a strong solution of
.sulphydrate of sodium, which I subject to the action of carbonic acid, by drawing or
forcing through it carbonic acid gas, or gases more or less rich in carbonic acid, and
thus produce carbonate of sodium. Strong solutions of sulphydrate of sodium are
readily acted upon by carbonic acid, the action being as follows:-
2 Na HS + CO2 + H₂O = Na₂ CO3 + 2 HS.
The small quantity of strontia or baryta still left in the liquor separates out as
carbonate of strontium or of barium, during the carbonating process.
If the solutions are of a strength of about 30° Twaddell or more, which will depend
upon the previous boiling down, the soda crystallizes out as carbonate with five (5)
molecules of water of crystallization, but, if the solutions are weaker than say 20°
Twaddell, common soda-crystals are obtained, or, if very weak solutions are used, no
crystallization takes place. I prefer, however, to use the solution of sulphydrate of
sodium as strong as possible, and, in this case, I separate the crystals of carbonate of
soda from the remaining liquor and make the soda-crystals ready for the market in the
ordinary manner, whilst the weak liquor, from which these crystals have been obtained,
is boiled down, and, if not fully converted into carbonate, is returned into the
carbonating apparatus.
The sulphuretted hydrogen given off during the carbonating process is easily
converted into sulphurous acid by passing it through a "Claus" kiln, and the sulphu-
rous acid can be used for making sulphuric acid. If the sulphuretted hydrogen is not
mixed with too great a proportion of oxygen, which depends on the composition of the
gases used for carbonating, it can readily be converted into sulphur by passing it
through a "Claus" kiln or by some other suitable process; I thus recover (either as
sulphur or as sulphur dioxide) not only the sulphur from the sulphate of sodium, but
also the sulphur from the sulphate of strontium or of barium used in my process.
Instead of the sulphate of sodium, I sometimes use, in my process, sulphate of
potassium, which acts in the same manner as the sulphate of sodiuin.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I wish it understood that I claim :-
:
First. The production of hydrate of strontium or of barium and sulphydrate of
sodium or of potassium by the reduction of a mixture of sulphate of strontium or of
barium and sulphate of sodium or of potassium and the mutual decomposition of the
sulphides thus obtained, substantially as hereinbefore described.
Second. In the production of hydrate of strontium or of barium and sulphydrate
of sodium or of potassium by my process, the use of the solution of sulphide of sodium

page_text: or of potassium obtained in the said process for the decomposition of a solution of
sulphide or sulphydrate of strontium or of barium, substantially as hereinbefore
described.
Third. The production of hydrate of strontium or of barium and carbonate of sodium
or of potassium by reducing a mixture of sulphate of strontium or of barium and
sulphate of sodium or of potassium and treating with carbonic acid the solution of
sulphydrate of sodium or of potassium obtained from the product of such reduction,
substantially as hereinbefore described.
Fourth. The production of hydrate of strontium or of barium and carbonate of
sodium or of potassium by mixing with a solution of sulphide or sulphydrate of
strontium or of barium a solution containing sulphide of sodium or of potassium (with
or without sulphydrate of sodium or of potassium) and decomposing the resulting
sulphydrate of sodium or of potassium by carbonic acid, substantially as hereinbefore
described.
Fifth. The recovery of the sulphur both from the sulphate of strontium or of barium
and from the sulphate of sodium or of potassium as hereinbefore described.