IMPROVEMENTS IN THE TREATMENT OF CERTAIN PHOSPHATIC MATERIALS
Year: 1884

page_text: I, HENRY BRUNNER of Cliff House, Appleton, Widnes in the county of Lancaster,
Manufacturing chemist, do hereby declare the nature of my said invention for
"IMPROVEMENTS IN THE TREATMENT OF CERTAIN PHOSPHATIC MATERIALS," to be
as follows:-
Natural or artificial phosphatic materials containing such bases as lead, copper,
manganese, iron, or alumina (especially the two latter) in considerable quantity,
either alone or in conjunction with calcium or magnesium, or both, are of little
value for the manufacture of superphosphate, as the product obtained from most of
them is apt to "go back as it is called, that is, the phosphoric acid in it becomes
to a greater or less extent again insoluble in water, and hitherto no satisfactory
method has been discovered for separating the other bases in these phosphates and
obtaining calcic phosphates therefrom on a commercial scale.
"
The process hitherto known to me by which this result was sought, nearest
resembling present invention is as follows-
.
When ferrous, ferric or aluminium phosphates are intimately mixed with calcium
oxide, or calcium carbonate, and the mixture heated to redness for a considerable
time and the mass after cooling be treated with dilute hydrochloric or other acid,
the solution will be found to contain calcium phosphate together with more or less
of the bases with which the phosphoric acid was originally combined, and the
insoluble residue will consist of ferric oxide or alumina together with undecomposed
phosphate. In the case of ferrous phosphate it is of course necessary that air
should be admitted during the beating operation in order to convert the ferrous
into ferric oxide.
From the solution so made, an impure di-calcic phosphate can be obtained by
precipitation.
It will also be found that, if the phosphate employed contained silica, a portion
of this will have become soluble in the acid used, and will on precipitation be
found with the calcic phosphate.
If the temperature to which the mixture is heated be raised to such a point that
the mixture fuses, a smaller proportion of the phosphoric acid is made soluble
than if the mixture be calcined or roasted at a lower temperature,

page_text: But the difficulty of making a sufficiently intimate mixture, and the length of
time for which it must be 'heated, are so great that this process of converting the
above named phosphates into calcium phosphato. would not be practicable on a
large scale.
Now the first part of my invention consists in a modification of this process.
In place of lime or carbonate of lime I use chloride of calcium. By this means the
conversion is effected much more rapidly and completely. It is more easy to obtain
an intimate mixture, as the calcium chloride may be employed to commence with,
in form of solution, and as it fuses at a comparatively low temperature, the danger
of making insoluble phosphates by over-heating is avoided. Air is admitted
when necessary. When the mixture is heated, hydrochloric acid is given off and
may be condensed for after use.
The cooled mass on being treated with dilute hydrochloric or other acid gives up
the whole of its phosphoric acid in the solution. The solution contains calcic
phosphate and some portion of the bases with which the phosphoric acid was
originally combined, and if the phosphate used contained silica, some of it also will
be found in solution, but not so much as if calcic oxide or carbonate had been used."
In the case of normal aluminium phosphate the reaction appears to be:
Al, (PO) + 3 H, O + 3 Ca Cl, = 2 (Ca H. PO), Cn C₁₂ + Al, 0, + 4 H Cl.
a portion of the Ca Ol remaining undecomposed and insoluble in water.
In the case of ferrous and ferric phosphates it is complicated by the fact that
ferrous and ferric chlorides are formed, but these in the presence of air and vapour
of water are converted into insoluble ferroso-ferric and ferric oxides, with evolution
of hydrochloric acid. In the case of metals yielding after calcination with calcium
chloride, oxides soluble in hydrochloric or other acid, such oxides may be removed
"before precipitating the calcium phosphates by well known analytical methods, as
for example, lead and copper may be removed from their acid solution by
precipitation with sulphuretted hydrogen.
The second part of my invention consists in digesting the impure solution of
'calcic phosphate formed as above mentioned, when such impurity is due to the
presence of aluminium or iron phosphate, with a sufficient quantity of precipitated
di or tri-calcic phosphate. The operation may take place at ordinary temperature
or at any temperature up to boiling point, and the reaction proceeds more rapidly
at a higher temperature. It will then be found that the calcic phosphate added
goes into solution, while ferric (and) aluminium phosphate is precipitated, and
may be removed by filtration.
or
The calcic phosphates in the solution after decanting are precipitated preferably
by lime, and the chloride of calcium in solution evaporated and used over again to
convert, according to the first part of my invention, fresh quantities of crude
phosphatic material or the precipitated ferric (and) aluminium phosphates obtained
as already described.
The presence of calcium oxide, calcium carbonate, or calcium sulphate does not
materially affect the calcination process. Magnesium Chloride may be used in place
of calcium chloride, when the result will be the production of Magnesium
phosphate.

page_text: COMPLETE SPECIFICATION,
I, HENRY BRUNNER of Cliff House, Appleton Widnes, (now Ditton Iron Works,
Ditton) in the County of Lancaster, Manufacturing Chemist, do hereby declare the
nature of my said invention for "IMPROVEMENTS IN THE TREATMENT OF CERTAIN
PHOSPHATIC MATERIALS" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
Natural or artificial phosphatic materials containing such bases as lead, copper,
manganese, iron or alumina (especially iron) in considerable quantity either alone
or in conjunction with calcium or magnesium compounds or both, are of little
value for the manufacturer of super phosphates. The phosphoric acid in the super
phosphates made from them is apt to revert or change to a condition insoluble in
water, and no satisfactory method has been discovered of separating the other bases
in such phosphates and obtaining calcic or magnesic phosphate from them on a
commercial scale. Now my invention is designed to effect these desired results and
is performed as follows:
In treating natural or artificial phosphates of iron, alumina, or other bases which
contain three equivalents, or less than three equivalents of magnesium or calcium
for each equivalent of phosphoric acid present, I add to the finely ground materials,
hydrochloric acid in sufficient quantity to convert into the form of chloride all the
calcium and magnesium present in the material. I then add, if necessary, calcium
(or magnesium) chloride either in the form of concentrated solution or otherwise,
but so as to ensure an intimate mixture, and in such quantity that there shall not
be less than three equivalents of calcium or magnesium in the form of chloride for
each equivalent of phosphoric acid contained in the mixture.
.
The mixture is then dried, (if necessary) and calcined or roasted in a suitable
furnace.
The furnace employed for the calcination or roasting must be of such construction
as to allow of the admission of air in sufficient quantity to peroxidise the metallic
bases, and of vapor of water to aid in the formation of hydrochloric acid.
The bydrochloric acid (and also any chloride) evolved is condensed in any suitable
manner for after use.
The temperature of the furnace must be so regulated as to allow of the peroxidation
of the metallic bases, to ensure their becoming insoluble in dilute acids, and to
ensure the decomposition of the calcium (or magnesium) chloride within reasonable
time, yet not so high as to cause any fritting or fluxing. A dull to a moderate red.
heat will be found sufficient except in the case of aluminium phosphate, which
requires a temperature approaching a bright red heat to render the alumina
sufficiently insoluble.
The calcined mixture after cooling is lixiviated with dilute hydrochloric or other
acid.
In the case of metals yielding oxides which after calcination with calcium (or
magnesium) chloride are soluble in dilute hydrochloric acid as for instance copper,
such metals can be removed from the hydrochloric acid solution by treatment with
hydrogen sulphide or a soluble calcium or other sulphide,

page_text: . Should the hydrochloric acid solution be found to contain as it may do with
imperfect ronating or calcining iron or aluminium phosphate in any considerable
quantity, it or they may be removed therefrom by digesting the solution with a
sufficient quantity of di or tri calcic (or magnesic) phosphate using by preference
such phosphate as has been obtained by precipitation. The operation may take
place at ordinary temperature, or at any temperature up to boiling point, it will bo
found that the added calcic or magnesic phosphate goes into solution, while iron
and aluminium phosphate is precipitated and may be removed by filtration or
or
decantation.
The calcium (or magnesium) chloride solution remaining after the precipitation
therefrom of the calcic (or magnesic) phosphate may be concentrated to be used in
treating a fresh quantity of crude phosphatic material, or used in the condensing
apparatus in place of water,
4
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1st. The improvements in the treatment of phosphatic materials containing iron
or aluminium with or, without other bases, which consist in adding to the
pulverized material hydrochloric acid or calcium or magnesium chloride, or both
hydrochloric acid and calcium (or magnesium) chloride in such proportions that
there shall be present in the mixture at least three equivalents of calcium (or
magnesium) in the form of chloride for each equivalent of phosphoric acid contained
therein and calcining or roasting the material after thorough mixture and drying
and then lixiviating with dilute hydrochloric acid or its equivalent and separating
the precipitate.
L
2nd. The process of separating iron and aluminium phosphates from hydrochloric
acid solutions of calcium and magnesium phosphates by digesting with di or tri
calcic (or magnesic) phosphate, substantially as described.
Dated this 22nd day of Juno 1885,
WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
and 323, High Holborn, London,
Patent Agents for the Applicant.