IMPROVEMENTS IN THE TREATMENT OF PHOSPHATE OF LIME
Year: 1881

page_text: LETTERS PATENT to Ernest Solvay, of Brussels, in the Kingdom of Belgium,.
Manufacturer, for an Invention of "IMPROVEMENTS IN THE TREATMENT
OF PHOSPHATE OF LIME."
PROVISIONAL SPECIFICATION left by the said Ernest Solvay at the
Office of the Commissioners of Patents on the 31st May 1881.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer.
"IMPROVEMENTS IN THE TREATMENT OF PHOSPHATE OF LIME."
Some native phosphates of lime, for instance, those found in the Ciply bed, near
Ciply, in Belgium, are very calcareous, the surplus lime in the Ciply native
phosphates being carbonate of lime.
The object of this Invention is the application of the said calcareous phosphates
of lime in the manufacture of soda and potash by the ammonia process (whether
ordinary ammonia or compound ammonia be used in the said process), firstly, for
the purpose of decomposing the hydrochlorate of ammonia produced in the said
manufacture, by means of the non-phosphated lime which accompanies the said
phosphates, and, secondly, to produce a residue of calcareous phosphate containing
very little lime in excess; the production of carbonic acid may also be combined
with the processes employed.
The said processes are as follows:-
The native phosphate of lime is reduced to powder and then lixiviated,
so as to carry off the lighter particles of carbonate of lime in connection therewith.
The phosphate of lime thus enriched is then calcined, and after being thus treated
the material is fit to be used in the regeneration of the ammonia contained in the
hydrochlorate of ammonia, produced in the manufacture of soda and potash; or
previously to its being thus used it may be lixiviated a second time so as to
remove still more of the lime, the light particles of which do not adhere to the
grains of phosphate. The phosphate of lime might be used in the regeneration of
the ammonia, as above described, without its being calcined, but then instead of
ammonia carbonate of ammonia would be produced. In either case the greater
part of the lime, or of the carbonate of lime in the material, is transformed into

page_text: chloride of calcium, which may be readily separated by means of water from the
insoluble, tribasic, calcareous phosphate (without any change taking place).
The phosphate of lime thus obtained contaios but little excess of lime, and may
be disposed of as an article of commerce.
The calcination of the powdered native phosphate of lime, whether enriched by
lixiviation or not, may be effected in two different ways, both about equally
advantageous. The first process consists in agglomerating the material with
clay, magnesia, and even pitch, or any other suitable agglutinating material in any
suitable apparatus; the agglomerated material is then calcined in the ordinary way
in a kiln such as is used for calcining limestone. The second. process consists in
mixing pulverised fuel with the pulverised phosphate of lime, and then by burning
the said fuel in suitable apparatus, effecting the calcination of the said phosphate.
This process of calcination may be effected in any of the well known furnaces
for roasting pulverized pyrites, for the purpose of obtaining sulphurous acid. The
two processes herein before just described being simple and practical will be readily
understood without further description. It should however be borne in mind that
in both cases the carbonic acid given off may be collected for use in the manufacture
of soda.
In order that in the regeneration of ammonia by means of the lime
contained in the phosphate of lime, the lime be transformed as completely as
possible into chloride of calcium, the process must be carried out in a special
manner.
In the process of regenerating the ammonia a notable excess of lime is generally
added to the hydrochlorate of ammonia in solution, so as to effect with certainty
the complete decomposition of the hydrochlorate of ammonia, and to prevent any
of the ammonia being lost. But the addition of such excess of lime is inapplicable
when for lime is substituted calcined calcareous phosphate, for a phosphate with
a considerable excess of lime would be produced of less value than a purer
phosphate.
To obviate this I treat the native phosphate systematically by means of the
liquid which is to be decomposed, that is to say, I cause the said phosphate to pass
through a solution of hydrochlorate of ammonia, richer and richer as the said
phosphate progresses, or I cause the said liquid to pass upon a phosphate containing
more and more surplus lime.
. These operations may be carried out in apparatus consisting of a tower or
vertical cylinder provided from top to bottom with a series of plates or shelves,
and with an agitator having arms upon it, and extending from top to bottom of
the said tower or vertical cylinder; the phosphate of lime is fed into the apparatus
upon the upper plate or shelf, and being acted upon by the agitator falls gradually
down, passing from shelf to shelf to the bottom whilst the liquid (hydrochlorate of
ammonia) is introduced at the bottom of the apparatus, and as it rises fills the
tower or cylinder completely. When the said phosphate has reached the bottom
of the tower or cylinder it is nearly free from lime, and may be removed by any
suitable means.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernest Solvay in the Great Seal Patent Office on the 24thN ovember
1881.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer.
"IMPROVEMENTS IN THE TREATMENT OF PHOSPHATE OF LIME."
Some native phosphates of lime, for instance, those found in the Ciply bed, near
Ciply, in Belgium, are very calcareous, the surplus limo in the Ciply native
phosphates being carbonate of lime. The object of this Invention is the application
of the said calcareous phosphates of lime in the manufacture of soda and potash by
the ammonia process (whether ordinary ammonia or compound ammonia be used in
the said process), firstly, for the purpose of decomposing the hydrochlorate of
ammonia produced in the said manufacture by means of the non-phosphated lime
which accompanies the said phosphates; and, secondly, to produce a residue of
calcareous phosphate containing very little lime in excess. The production of
carbonic acid may also be combined wish the processes employed.
The said processes are as follows:-
The native phosphate of lime is reduced to powder, and then lixiviated so as to
carry off the lighter particles of carbonate of lime in connexion therewith. The
phosphate of lime thus enriched is then calcined, and after being thus treated the
material is fit to be used in the regeneration of the ammonia contained in the
hydrochlorate of ammonia produced in the manufacture of soda and potash; or
previously to its being thus used it may be lixiviated a second time, so as to remove
still more of the lime, the light particles of which do not adhere to the grains of
phosphate.
The phosphate of lime might be used in the regeneration of the ammonia, as
above described, without its being calcined, but then, instead of ammonia, carbonate
of ammonia would be produced. In either case the greater part of the lime, or of
the carbonate of lime, in the material is transformed into chloride of calcium, which
may be readily separated by means of water from the insoluble tribasic calcareous
phosphate (without any change taking place).
The phosphate of lime thus obtained contains but little excess of lime, and may
be disposed of as an article of commerce. The calcination of the powdered native
phosphate of lime, whether enriched by lixiviation or not, may be effected in two
different ways, both about equally advantageous. The first process. consists in
agglomerating the material with clay, magnesia, and even pitch, or any other
suitable agglutinating material, in any suitable apparatus; the agglomerated
material is then calcined in the ordinary way in a kiln, such as is used for
calcining limestone.
The second process consists in mixing pulverised fuel with the pulverised phos-
phate of lime, and then, by burning the said fuel in suitable apparatus, effecting the
calcination of the said phosphate.
This process of calcination may be effected in any of the well known furnaces
for roasting pulverised pyrites for the purpose of obtaining sulphurous acid. The
two processes herein before just described being simple and practical, will be readily
understood without further description.
It should however be borne in mind that in both cases the carbonic acid given off
may be collected for use in the manufacture of soda.
In order that in the regeneration of ammonia by means of the lime contained in
the phosphate of lime the lime be transformed as completely as possible into
chloride of calcium, the process must be carried out in a special manner.
In the process of regenerating the ammonia a notable excess of lime is generally
added to the hydrochlorate of ammonia in solution, so as to effect with certainty
the complete decomposition of the hydrochlorate of ammonia, and to prevent any
of the ammonia being lost. But the addition of such excess of lime is inapplicable
when for lime is substituted calcined or uncalcined calcareous phosphate, for a

page_text: phosphate with a considerable excess of lime would be produced, of less value
than a purer phosphate.
To obviate this I treat the native phosphate systematically by means of the
liquid which is to be decomposed, that is to say, I cause the said phosphate to pass
through a solution of hydrochlorate of ammonia richer and richer as the said
phosphate progresses, or I cause the said liquid to pass up on a phosphate containing
more and more surplus lime.
These operations may be carried out in apparatus consisting of a tower or vertical
cylinder provided from top to bottom with a series of plates or shelves, and with
an agitator having arms upon it and extending from top to bottom of the said
tower or vertical cylinder.
The phosphate of lime is fed into the apparatus upon the upper plate or shelf,
and being acted upon by the agitator, falls gradually down, passing from shelf to
shelf to the bottom, whilst the liquid (bydrochlorate of ammonia) is introduced at
the bottom of the apparatus, and as it rises fills the tower or cylinder completely.
When the said phosphate has reached the bottom of the tower or cylinder it is
nearly free from lime and may be removed by any suitable means.
Having now described the nature of my said Invention, and the manner of
performing the same, I claim as my Invention,―
Firstly. The process herein before described of producing tribasic calcareous
phosphate containing very little excess of lime from native phosphate of lime, that
is to say, by utilizing the said native phosphate of lime for the regeneration of the
ammonia contained in the hydrochlorate of ammonia produced in the manufacture
of soda and potash by the ammonia process, such native phosphate of lime having
been previously prepared for the said process by its pulverization, lixiviation, and
calcination, or by its calcination, substantially as described.
✓ Secondly. The process of agglomerating pulverised native tribasic phosphate of
lime, whether previously enriched by lixiviation or not, with any suitable
agglutinating material in any suitable apparatus in order to be able subsequently
to calcine the said phosphate of lime in a kiln such as is used for calcining lime-
stone, substantially as described.
Thirdly. The process of mixing pulverised fuel with pulverised native tribasic
phosphate of lime in order to be able subsequently to calcine the said phosphate of
lime in any of the well known furnaces for roasting pulverised pyrites for the
purpose of obtaining sulphurous acid, substantially as described.
Fourthly. In the process of regenerating the ammonia contained in the hydro-
chlorate of ammonia produced in the manufacture of soda and potash by the
ammonia process, treating the said hydrochlorate of ammonia systematically by
means of native basic calcareous phosphates so as to cause the liquid to pass upon
a phosphate containing more and more surplus lime as the said liquid progresses,
or to cause the said phosphate to pass through liquid hydrochlorate of ammonia
richer and richer as the said phosphate advances, substantially as described.
Fifthly. For the purpose of dissolving systematically the excess of lime in the
calcareous phosphate by means of a solution of hydrochlorate of ammonia, the
application and adaptation of apparatus consisting of a tower or vertical cylinder
provided from top to bottom with a series of shelves or plates, and with an agitator
having arms upon it and extending from top to bottom of the said tower or
cylinder, substantially as described.
In witness whereof, I, the said Ernest Solvay, have hereunto set my hand
and seal, this Twenty third day of November, in the year of our Lord
One thousand eight hundred and eighty one.