A Process for Obtaining Mother Liquors Free from Magnesian Salts • in the Manufacture of Carbonate of Potash by Means of the. Double Carbonate of Potash and Magnesia.
Year: 1886

page_text: Date of Application, 22nd Nov., 1886.
Complete Left, 20th Aug., 1887.
Complete Accepted, 20th Sept., 1887.
A Process for Obtaining Mother Liquors Free from Magnesian Salts
•
in the Manufacture of Carbonate of Potash by Means of the.
Double Carbonate of Potash and Magnesia.
I EDWIN POWLEY ALEXANDER of 36 Southampton Buildings in the County of
Middlesex, Fellow of the Institute of Patent Agents do hereby declare the nature of
this invention (communicated to me from abroad by Etienne Joseph Louis Delsol
of Villeneuve, Lot, in the Republic of France Engineer) to be as follows:-
In the manufacture of Carbonate of Potash from a soluble salt of Potassium by
Engel's process under Letters Patent No. 184 dated Jany. 14th A.D. 1881, mother
liquors are obtained which in addition to the untransformed salts of Potash contain
Magnesian salts. These salts are formed at the expense of a part of the Magnesia or
Carbonate of Magnesia introduced in the manufacture.
In order to recover the salts of Potash contained in these liquors they may be
treated in two ways:-
1. The salts of Potash may be separated from the salts of Magnesia by the method
known in the manufacture of Stassfurt.
2. The mother liquors may be employed to manufacture salts of Potash such as Alum,
Saltpetre and the like.
But in the second case the Magnesian salts often create considerable difficulties
which entail heavy expenses particularly in the manufacture of Saltpetre.
It would therefore be doubly advantageous to obtain mother liquors free from
Magnesian salts.
For this purpose in the solution of the salt of Potash employed for the formation
of the double salt; a quantity of Carbonate of Soda may be introduced equivalent
to the quantity of Carbonate of Potash which it is desired to obtain. The Carbonate
of Soda precipitates the Magnesian Salt the moment it forms or prevents its
formation, and, at the end of the operation the mother liquors contain no Magnesian
Salt but the corresponding salt of Sodium.
If for example Chloride of Potassium and Magnesia is employed the following
equation is obtained :—

page_text: The Carbonate of Soda may obviously be replaced by bi-carbonate of Soda.
This process presents another advantage, it allows of the dispensing if desired with
the use of Magnesia in the state of oxyde, hydrate or carbonate, and of its replace-
ment by a soluble salt of Magnesium put in solution with the salt of Potassium.
For example with a solution of Chloride of Potassium and Chloride of Magnesium
the reaction represented by the following equation is obtained :-
The Carbonate of Soda may obviously be replaced by bi-carbonate of Soda.
This process presents another advantage, it allows of the dispensing if desired with
the use of Magnesia in the state of oxyde, hydrate or carbonate, and of its replace-
ment by a soluble salt of Magnesium put in solution with the salt of Potassium.
For example with a solution of Chloride of Potassium and Chloride of Magnesium
the reaction represented by the following equation is obtained :-
====
2 Mg Cl² + 2 K Cl + 3 Na³ CO³ + CO³ + 9 H² 0 =
2 [Mg KH (CO³)² + 4 H³0] + 6 Na Cl.
In this manner may be utilized the solutions obtained in treating by water the raw
salts of Stassfurt (Karnallite, Kainite &c.)-The foreign salts which these solutions
contain do not affect the reaction.
The following are the essential features of the said invention :-
1. Adding carbonate or bi-carbonate of Soda to the solution of Potassic Salt which
with the Magnesia in the state of Oxyde, Hydrate, or Carbonate, and free Carbonic
Acid serves to prepare according to the Engel process described in the specification
No. 184 A.D. 1881 hereinbefore referred to a double Carbonate of Potash and
Magnesia in order to obtain mother liquors free from Magnesian salts; the quantity
of carbonate or bi-carbonate of Soda employed is equivalent to that of the Carbonate
of Potash it is desired to obtain and may be added gradually or all at once.
2. Replacing in this preparation the Magnesia and Carbonate of Magnesia by a
soluble salt of Magnesium added gradually or all at once in a solid stato or in a state
of solution and consequently employing solutions containing beforehand the necessary
salts of Potassium and Magnesium the quantity of carbonate or bi-carbonate of Soda
employed being then three times greater.
Dated this 22nd day of November 1886.

page_text: COMPLETE SPECIFICATION.
A Process for Obtaining Mother Liquors Free from Magnesian Salts
in the Manufacture of Carbonate of Potash by Means of the
Double Carbonate of Potash and Magnesia.
I EDWIN POWLEY ALEXANDER of 36 Southampton Buildings in the County of
Middlesex, Fellow of the Institute of Patent Agents do hereby declare the nature
of this invention (communicated to me from abroad by Etienne Joseph Louis Delsol
of Villeneuve Lot in the Republic of France, Engineer) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
In the manufacture of Carbonate of Potash from a soluble salt of Potassium by
Engel's process under Letters Patent No. 184 dated January 14th A.D. 1881 mother
liquors are obtained which in addition to the untransformed salts of Potash contain
magnesian salts. These Salts are formed at the expense of a part of the Magnesia or
Carbonate of Magnesia introduced in the manufacture which have afterwards to be
replaced.
In order to recover the salts of Potash contained in these mother liquors they may
be treated in two ways:-
1. The salts of Potash may be separated from the salts of Magnesia by the method
known in the manufactures of Stassfurts.
2. The mother liquors may be employed to manufacture Salts of Potash such as
Alum, Saltpetre, and the like.
But in the second case the Magnesian Salts often create considerable difficulties
which entail heavy expenses particularly in the manufacture of Saltpetre.
It would therefore be doubly advantageous to obtain mother liquors free from
magnesian salts.
For this purpose there may be introduced into the solution of the Salt of Potash
employed for the formation of the double salt, a quantity of Carbonate of Soda
equivalent to the quantity of Carbonate of Potash which it is desired to obtain. The
Carbonate of Soda precipitates the Magnesian Salt at the moment of its formation or
prevents its formation and, at the termination of the operation the mother liquors
contain no Magnesian salt but the corresponding salt of Sodium.
If for example Chloride of Potassium and Magnesia be employed the following
equation is obtained
2 Mg O+ 2 K Cl + Na² CO³ + 3 CO³ + 9 H³ ( =
2 [Mg KH (CO³)² + 4 H³ 0] + 2 Na Cl.
The Carbonate of soda may obviously be replaced by Bicarbonate of Soda.
This process presents another advantage, it allows of the dispensing if desired, with
the use of Magnesia in the state of Oxide, Hydrate, or Carbonate, and of its
replacement by a Soluble Salt of Magnesium in solution with the salt of Potassium.

page_text: For example with a solution of Chloride of Potassium and Chloride of Magnesium
the reaction represented by the following equation is obtained :-
the reaction represented by the following equation is obtained :—
2 Mg Cl² + 2 K Cl + 3 Na³ CO³ + CO² + 9 H² 0 =
2 [Mg K H (CO3)2 + 4 H³ 0] + 6 Na Cl.
In this manner may be utilized the solutions obtained in treating by water the raw
salts of Stassfurt (Karnallite, Kaïnite and the like). The foreign salts which these
solutions contain do not affect the reaction.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. The hereindescribed process consisting in the addition of Carbonate or Bi-
carbonate of soda to the solution of potassic salt which, with the magnesia in the state
of oxide, hydrate, or carbonate, and free carbonic acid, serves to prepare, according to
the Engel process described in the specification No. 184 A.D. 1881 a double carbonate
of Potash and Magnesia with a view to obtaining Mother liquors free from Magnesian
Salts the quantity of Carbonate or Bicarbonate of Soda employed being equivalent
to that of the Carbonate of Potash it is desired to obtain and being added either
gradually or at one time.
2. Replacing in this preparation the Magnesia and Carbonate of Magnesia by a
soluble salt of Magnesium added either gradually or at one time in a solid state or
in a state of solution and consequently employing solutions containing beforehand the
necessary salts of Potassium and Magnesium, the quantity of Carbonate or Bicarbonate
of Soda employed being then three times greater.
I 100
EDWIN P. ALEXANDER, Fel. Inst. P.A.