IMPROVEMENTS IN THE TREATMENT OF PHOSPHORITES FOR THE MANUFACTURE OF MANURES AND OF THE REAGENTS EMPLOYED
Year: 1882

page_text: LETTERS PATENT to John Imray of N° 28 Southampton Buildings Chancery
Lane in the County of Middlesex for an Invention of IMPROVEMENTS IN THE
TREATMENT OF PHOSPHORITES FOR THE MANUFACTURE OF MANURES AND OF
THE REAGENTS EMPLOYED Communicated to him from abroad by General
Louis Daudenart of Brussels in the Kingdom of Belgium
PROVISIONAL SPECIFICATION left by the said John Imray at the Office
of the Commissioners of Patents on the 20th September 1882.
JOHN IMRAY of N° 28 'Southampton Buildings Chancery Lane in the County
of Middlesex "IMPROVEMENTS IN THE TREATMENT OF PHOSPHORITES FOR THE
MANUFACTURE OF MANURES, AND OF THE REAGENTS EMPLOYED." [Communi-
cated to him from abroad by 'General Louis Daudenart of Brussels in the Kingdom
of Belgium]
This invention relates to the treatment of phosphorites so as to separate from
them carbonate of lime, and obtain tricalcic phosphate suitable for being converted
into phosphate soluble in water or in organic ammoniacal salts so as to be readily
assimilated by vegetables; For this purpose the phosphorite is in the first place
decarbonated by subjecting it to heat in a kiln made in compartments which are
worked in rotation as in a Hoffman brick kiln. The calcined and cooled
phosphorite is then hydrated in an open semicylindrical steam cased vessel provided
with agitators working under a grating placed at some distance from the bottom.
On this grating the blocks of calcined phosphorite are placed and the vessel is
charged with water, which is heated to boiling point by the steam in the casing.
After about an hour of boiling the hydration is complete and the material is
washed in the same vessel so as to separate the lighter calcareous matter which
after agitation rises to the top, and which is run off by a flexible pipe attached to a
float by the movement of which its end is immersed in the liquid. When the
liquid becomes clear it is run off, and the solid residue is by means of a worm
arranged at the bottom of the vessel transferred to another vessel for subsequent
treatment. In cases where the material to be hydrated has been rendered very
hard and refractory by calcination, the hydration may be effected by steam, which
in uniting with the material produces a high temperature rising nearly to a red

page_text: heat, so that the most refractory portions become hydrated. This may be done in
a close vessel so that the steam which becomes superheated in passing through the
material may be employed for other heating purposes in the manufactory. After
hydration as above described the material has to be cleared of the hydrate of lime.
For this purpose it is treated at boiling heat with a soluble salt of magnesia,
preferably the chloride or sulphate, by which there is a reaction giving calcium
chloride and hydrate of magnesia. The mass is then cooled in a vacuum vessel
supplied with a small stream of water, and carbonic acid (which may be the gas
liberated during the calcination of the phosphorite) is passed through it. By this
in the course of a few hours the magnesium chloride is reproduced and the
carbonate of lime, and the substances arrange themselves so that at the bottom
there is a dense layer of tricalcic phosphate and above this a layer of carbonate of
lime so light that it can readily be separated from the phosphate by decantation,
and so pure and white that it is available for various uses; at the top there is
solution of magnesium chloride. The phosphate layer being separated is well
washed, and as it contains about 70 per cent of tricalcic phosphate it is easily
rendered soluble in water by treatment with acid. When it has to be rendered
soluble in ammonium citrate, it is dissolved in hydrochloric acid so diluted that the
resultant solution has a strength of about 18° Beaumé, and it is then treated not as
usual with lime produced by calcination of limestone, but with the calcined and
hydrated phosphorite preferably washed, or it may be treated with magnesian
hydrate by which soluble phosphate of lime is precipitated leaving magnesium
chloride in solution. It is of advantage to restore the hydrochloric acid engaged
in the calcium chloride by treating a solution of the chloride at a strength of about
16° Beaumé with hydrated magnesia or neutral carbonate of magnesia and carbonic
acid, thus producing magnesium chloride and carbonate of lime which can be
separated from the solution. The solution is then concentrated to about 44° Beaumé
and allowed to cool into a hard mass which is broken into fragments from which
the hydrochloric acid is disengaged by heat and steam, leaving a residue of magnesia
which is bydrated and can be used as above described either directly or after
carbonation. Instead of employing magnesium salts as above described, salts of
other metals, such as manganese, zinc or iron chlorides or zinc sulphate might be
employed, the resultant oxides having certain commercial value. In order to
economise the magnesian or other reagents employed, sea water which contains
suitable salts can be used for the hydration, the reaction and the washing. When
this water is mixed with phosphorite previously decarbonated and hydrated it
disengages a quantity of caustic lime leaving hydrate of magnesia which being very
light can be easily separated from the lime. For obtaining and applying the sea
water a reservoir is formed on the beach having its bottom above low water level
and its embankment above the highest tides, provided on the side next the sea
with sluices by which water at high tide is admitted till it attains a suitable depth
in the reservoir. On the land sides of the reservoir are formed basins in which is
placed the decarbonated and hydrated phosphorite. Water from the reservoir is
admitted by sluices to these basins to a suitable depth and the sluices are closed.
The material in the basins is agitated by rakes until it is found by testing the
filtered liquid that it contains no magnesia. After subsidence, the liquid is run off
into secondary basins to a level somewhat higher than the primary basins so that
the deposited phosphate and lime are retained in the primary basins. After settle-
ment during about 24 hours the excess of liquid is run off into the sea, and the
magnesia is collected after filtration through sand or by filter presses. The most
suitable phosphate for agriculture being the ammoniaco-magnesian phosphate, it is
of advantage to produce it with cheapness and facility, for which purpose neutral
phosphate of magnesia may be added to any ammoniacal liquor, so as to produce
the insoluble ammoniaco-magnesian phosphate.constituting a valuable manure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the, said John Imray in the Great Seal Patent Office on the 20th March
1883..
28
"
JOHN IMRAY of N° 28 Southampton Buildings Chancery Lane in the County
of Middlesex "IMPROVEMENTS IN THE TREATMENT OF PHOSPHORITES FOR THE
MANUFACTURE OF MANURES AND OF THE REAGENTS EMPLOYED A communi-
cation to me from abroad by General Louis Daudenart of Brussels in the Kingdom
of Belgium.
This invention relates to the treatment of phosphorites so as to separate from
them carbonate of lime, and obtain tricalcic phosphate suitable for being converted
into phosphate soluble in water or in organic ammoniacal salts so as to be readily
assimilated by vegetables. For this purpose, the phosphorite is, in the first place,
decarbonated by subjecting it to heat in a kiln made in compartments which are
worked in rotation as in a Hoffinan brick kiln; each charge is thus made to
undergo gradual heating, decarbonisation and cooling, so that in about 15 days it
is ready for subsequent treatment. The calcined and cooled phosphorite is then
hydrated in an open semi-cylindrical steam cased vessel provided with agitators
working under a grating placed at some distance from the bottom On this grating:
the blocks of calcined phosphorite are placed, and the vessel is charged with water,,
which is heated to boiling point by the steam in the casing. After about an hour
of boiling, the hydration is complete and the material is washed in the same vessel,
so as to separate the lighter calcareous matter which, after agitation, rises to the
top; and which is run off. by a flexible pipe attached to a float so arranged as to
keep the mouth of the pipe submerged in the liquid. When the liquid becomes
clear, it is run off, and the solid residue is, by means of a worm arranged at the
bottom of the vessel, transferred to another semi-cylindrical vessel for subsequent
treatment. In cases where the material to be hydrated has been rendered very
hard and refractory by calcination, the hydration may be effected by steam, which,
in uniting with the material, produces a high temperature rising nearly to a red
heat, so that the most refractory portions become hydrated. This may be done in
a close vessel, so that the steam which becomes superheated in passing through the
material may be employed for other heating purposes in the manufactory. After
hydrations as above described, the material has to be cleared of the hydrate of lime.
For this purpose, it is treated at boiling heat with a soluble salt of magnesia,
preferably the chloride or sulphate, by which there is a reaction giving calcium
chloride and bydrate of magnesia, as indicated by the formula-
=
{Ph. 05. 3 Ca O, K (Ca. O. Ho)} + K (Cl. Mg.) + Aq.
(Mg O. H.O) + K (Cl. Ca) + Aq.
Ph. O. 3 Ca. O. + K
The mass is then cooled in a vacuum vessel supplied with a small stream of water,
and carbonic acid, (which may be the gas liberated during the calcination of the
phosphorite) is passed through it. By this, in the course of a few hours, the
imagnesium chloride is reproduced and the carbonate of lime and the substanese.

page_text: treatment with acid. When it has to be rendered soluble in ammonium citrate, it
is dissolved in hydrochloric acid so diluted that the resultant solution has a strength
of about 18° Beaumé, and it is then treated, not as usual with lime produced by
calcination of limestone, but with the calcined and hydrated phosphorite, preferably
washed. It is of advantage to restore the hydrochloric acid engaged in the calcium
chloride by treating a solution of the chloride at a strength of about 16° Beaumé
with hydrated magnesia or neutral carbonate of magnesia and of carbonic acid
made to pass through it, thus producing magnesium chloride and carbonate of lime
which can be separated from the solution. The solution is then concentrated by
evaporation to about 44° Beaumé and allowed to cool into a hard mass which is
broken into fragments, from which the hydrochloric acid is disengaged by heat and
steam, leaving a residue of magnesia which is hydrated and can be used as above
described, either directly or after carbonation. Instead of employing magnesium
salts as above described, salts of other metals, such as manganese, zinc or iron
chlorides, or zinc sulphate might be employed, the resultant oxides having certain
commercial value. In order to economise the magnesian or other reagents
employed, sea water which contains suitable salts can be used for the hydration,
the reaction and the washing. When this water is mixed with phosphorite
previously decarbonated and hydrated by hot water or steam, it disengages a
quantity of caustic lime, leaving hydrate of magnesia, which being very light,
remains long in suspension and can be easily separated from the lime. In this
case, in order to obtain phosphate soluble in citrate of ammonia, the solution of
tricalcic phosphate in hydrochloric acid should be neutralized by hydrate of
magnesia, by which the assimilable phosphate is precipated, leaving magnesium
chloride in solution as indicated by the formula-
2 (Ph 05. 3 CaO) + 3 Cl H = Ph 0%. 3 HO + 3 C1 Ca.
Ph 0, 3 HO + 3 Cl Ca + 2 Mg O = Ph 05. 2 Ca O. HO + 2 Cl Mg + Cl Ca.
For obtaining and applying the sea water, a reservoir is formed on the beach
having its bottom above low water level, and its embankment above the highe-t
tides, provided on the side next the sea with sluices by which water at high tide
is admitted till it attains a suitable depth in the reservoir. On the land sides of
the reservoir, are formed basins in which is placed the decarbonated and hydrated
phosphorite. Water from the reservoir is admitted by sluices to these basins to a
suitable depth, and the sluices are closed. The material in the basins is agitated by
rakes until it is found, by testing the filtered liquid, that it contains no magnesia.
After subsidence, the liquid is run off into secondary basins to a level somewhat
higher than the primary basins, so that the deposited phosphate and lime are
retained in the primary basins. After settlement, during about 24 hours, the excess
of liquid is run off into the sea, and the magnesia is collected after filtration
through sand or by filter presses. The most suitable phosphate for agriculture
being the ammoniaco-magnesian phosphate, it is of advantage to produce it with
cheapness and facility, for which purpose, neutral phosphate of magnesia may be
added to any ammoniacal liquor, so as to produce the insoluble ammoniaco-
magnesian phosphate constituting a valuable manure.
Having thus described the nature of the said invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent,
I claim,
:
First Effectng decarbonation of phosphorites by subjecting them to heat in
compartments of a kiln worked in rotation.
Second Hydrating decarbonated phosphorites by treating them under the
influence of heat with water or steam.
Third: Effecting separation of lime from phosphate by treating decarbonated,
hydrated and washed phosphorite with soluble salts of magnesia or of
manganese, zinc or iron.
Fourth: The application of sea water for enriching decarbonated and hydrated
phosphorite, and producing hydrated magnesia,

page_text: Fifth: The use of decarbonated phosphorites for precipitating from solution of
tricalcic phosphate in hydrochloric acid, a phosphate soluble in citrate of
ammonia, and therefore capable of assimilation by vegetables.
Sixth: The use of hydrated magnesia for precipitating from solution of tricalcic
phosphate in hydrochloric acid, a phosphate soluble in citrate of ammonia,
and therefore capable of assimilation by vegetables.
Seventh: The herein described process for reproducing the hydrochloric acid
employed for dissolving tricalcic phosphate, by transforming calcium chloride
into magnesium chloride and concentrating and decomposing the latter by
heat.
Eighth Treating liquids containing ammonia with neutral phosphate of magnesia,
for extraction of the ammonia, and the production of ammoniaco-magnesian
phosphate, available as manure.
In Witness whereof I the said John Imray have hereunto set my hand and
seal this Twentieth day of March in the year of our Lord, one thousand
eight hundred and eighty-three.