Improved Process relating to the Treatment and Production of Phosphates.
Year: 1897

page_text: Date of Application, 5th July, 1897
Complete Specification Left, 11th Mar., 1898-Accepted, 20th May, 1898
TRUVIDIUNAL DIECIFICATION.
Improved Process relating to the Treatment and Production of
Phosphates.
I, EUGÈNE MASSON-POLET of Hannut, Belgium, Manufacturer, do hereby declare
the nature of this invention to be as follows:-
The present invention relates to a process for treating natural phosphates,
whereby phosphated calcium carbonates-phosphates of lime containing carbon-
ates commonly called " gray chalk," such as is found in geological formations
are altered in such manner as to render them useful for agricultural purposes.
The process according to the present invention differs essentially from numerous
other processes suggested hitherto and mostly having for their purpose a trans-
formation by simple melting in the presence of certain fluxes, which failed to give
favourable results, as these processes do not bring about the requisite solubility,
which is essential for assimilation; in other words said processes do not transform
the phosphates into the condition of tetraphosphates or Thomas' phosphated slag.
In fact the phosphoric acid is not changed by the simple fusion of phosphated
calcium carbonates with fluxes so as to give a product equivalent to Thomas's
phosphated slag or tetraphosphate-for the production of this valuable bye-product
of metallurgical industries from phosphated calcium carbonates or natural phos-
phates more radical reactions are required.
As all the attempts to render natural phosphates assimilable have hitherto
failed, it was necessary to give up the idea of utilizing natural phosphates in their
original shape, that is to say with their calcareous gangue more or less transformed,
and to replace it by a process of transformation, which, according to the present
invention, consists in thoroughly extracting the phosphoric acid from the phos-
phates by melting them in furnaces in the presence of metals which will absorb
the whole phosphoric acid of the phosphates and afterwards in treating said metals
by ordinary de-phosphorising process, thus obtaining Thomas slag or tetraphos-
phates produced from gray chalk.
The process according to the present invention is therefore characterised by two
successive de-phosphorising operations: first, the de-phosphorising of natural
phosphates of lime in the presence of melted iron-ore and afterwards the de-
phosphorising of the product obtained by the Thomas process.
The first de-phosphorising stage of the process may be effected in ordinary fur-
naces for producing cast iron by using in them phosphated calcium carbonates
instead of the usual limestone-flux, which, beside bringing about the transforma-
tion desired, has the advantageous effect of avoiding the necessity of obtaining
special limestone flux and phosphorous slag which is often very expensive.
The phosphor cast-iron obtained by using natural phosphates is then treated
according to Thomas's process in which phosphorus passes into the slag forming
the desired assimilable tetraphosphates so that the transformation of phosphated
calcium carbonates or gray chalk according to this new process brings about at
once three technical results, viz.: the production of Thomas slag, the possibility of

page_text: dispensing with both the use of phosphorous slag in the furnace, and also ordinary
limestone flux.
BOULT & WADE,
Agents for the Applicant.
Improved Process relating to the Treatment and Production of
Phosphates.
I, EUGÈNE MASSON-POLET of Hannut, Belgium, Manufacturer, 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 present invention relates to a process for treating natural phosphates,
whereby phosphated calcium carbonates-phosphates of lime containing carbon-
ates commonly called ". grey chalk," such as is found in geological formations
are rendered useful for agricultural purposes. The process according to the pre-
sent invention differs essentially from numerous other processes suggested hitherto
and mostly having for their purpose a transformation by simple melting in the
presence of certain fluxes, which failed to give favourable results, as these processes
do not bring about the requisite solubility, which is essential for assimilation, in
other words said processes do not transform the phosphates into the condition of
tetraphosphates or Thomas' phosphated slag.
In fact the phosphoric acid is not changed by the simple fusion of phosphated
calcium carbonates with fluxes so as to give a product equivalent to Thomas' phos-
phated slag or tetraphosphates, for the production of this valuable bye-product of
metallurgical industries from phosphated calcium carbonates or natural phos-
phates more radical reactions are required.
As all attempts to render natural phosphates assimilable have hitherto failed,
it was found necessary to give up the idea of utilising natural phosphates in their
original shape, that is to say with their calcareous gangue more or less trans-
formed, and to replace it by a process of transformation, which, according to the
present invention consists in thoroughly extracting the phosphoric acid from the
phosphates by melting or fusing them in furnaces in the presence of metals which
will absorb the whole phosphoric acid of the phosphates and in afterwards treating
said metals by ordinary de-phosphorising process, thus obtaining Thomas slag or
tetraphosphates produced from grey chalk.
The process according to the present invention is therefore characterised by two
successive de-phosphorising operations: first, the de-phosphorising of natural phos-
phates of lime in the presence of melted iron-ore and afterwards the dephosphorising
of the product obtained by the Thomas process.
The first dephosphorising stage of the process may be effected in ordinary fur-
naces for producing cast-iron by using in them phosphated calcium carbonates
instead of the usual limestone-flux which, beside bringing about the transforma-
tion desired, has the advantage of avoiding the necessity of obtaining special lime-
stone flux and phosphorous slag which is often very expensive.
The phosphor cast-iron obtained by using natural phosphates is then treated
according to the Thomas's process in which phosphorus passes into the slag form-
ing the desired assimilable tetraphosphates so that the transformation of phos-
phated calcium carbonates or grey chalk according to this new process brings
about at once three important results, viz.: the production of Thomas slag, the

page_text: possibility of dispensing with both the use of phosphorous slag in the furnace and
also ordinary limestone.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:-
The process of transforming natural phosphated calcium carbonates or grey
chalk into Thomas slag or tetraphosphates consisting in melting them in the
presence of metals or ores so as to extract from them phosphoric acid which passes
into the metal and treating the phosphor metal thus obtained by the Thomas pro-
cess in order to transfer the phosphoric acid to the slag and form tetraphosphates
substantially as described.
Dated this 11th day of March 180º