IMPROVEMENTS IN THE TREAT- MENT OF PHOSPHATES OF LIME, AND IN THE PRODUCTION OF VALUABLE PRODUCTS THEREBY.
Year: 1874

page_text: LETTERS PATENT to Benjamin Tanner, F.C.S., of North Strand,
Dublin, Ireland, for the Invention of "IMPROVEMENTS IN THE TREAT-
MENT OF PHOSPHATES OF LIME, AND IN THE PRODUCTION OF VALUABLE
PRODUCTS THEREBY.'
"
PROVISIONAL SPECIFICATION left by the said Benjamin Tanner
at the Office of the Commissioners of Patents, with his Petition, on
the 2nd June 1874.
I, BENJAMIN TANNER, F.C.S., of North Strand, Dublin, Ireland,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE TREATMENT OF PHOSPHATES OF LIME, AND IN THE PRODUCTION OF VALUABLE
PRODUCTS THEREBY," to be as follows:-
-
This Invention consists in certain improvements in the treatment of
phosphates of lime whereby valuable products are obtained in an
economical manner and of such character and composition as may be
desired.

page_text: For the, convenience of description and reference the following
paragraphs in which the processes embraced by this Invention are
described are numbered consecutively.
1. Any of the ordinary forms of phosphate of lime of commerce (such
as phosphorites, coprolites, apatite, phosphatic guanos, bone ash, or
animal charcoal), or any form of precipitated phosphate of lime, or any
other form of phosphate of lime, or any mixture thereof, is or are
treated with hydrochloric acid, either in the gaseous or liquid condition
and either with or without the assistance of heat. By preference
hydrochloric acid of 15° to 20° Twaddell's hydrometer is employed for
this purpose, and by these and similar arrangements solutions in
hydrochloric acid of any of the forms of phosphate of lime or mixtures
thereof are obtained.
2. The solutions obtained as described in the preceding paragraph, or
either of them are or is treated with sulphuric acid (in any more or less
dilute condition) in such quantity as to combine with the whole or any
part of the lime or calcium in the solution to be worked. By preference
and for the sake of example (but subject to the principle laid down in
the paragraph hereof numbered 4), the sulphuric acid is added in such
quantity as will combine with the whole of the lime present. By this
treatment the desired quantity of lime or calcium is precipitated from
the solution in the form of sulphate of lime, which is separated from the
liquid portion by means of filtration, decantation, or otherwise, and may
be subsequently washed by water.
-
Having separated the sulphate of lime the liquid portion is again
employed as a solvent for any of the before-named forms of phosphate
of lime, or any mixtures thereof, and the resulting solution is treated
with sulphuric acid (of any desired strength) in such quantity as will
combine (subject as above mentioned) with the whole of the lime or
'calcium present. The sulphate of lime is again removed from the
liquid portion by means of filtration, decantation, or otherwise, and may
subsequently be washed with water. The liquid portion thus obtained
is again employed as a solvent for any of the before-mentioned forms of
phosphate of lime or any mixtures thereof, and the resulting solution is
evaporated in suitably constructed furnaces.
Having ascertained by suitable tests the relative proportion of the
lime or calcium to the phosphoric acid, if the lime or calcium be in

page_text: excess of the desired proportions then at any stage of the evaporation,
but by preference (when the action of the phosphoric acid or the
chloride of calcium and the evolution of hydrochloric acid is getting
sluggish) sulphuric acid (of any desired strength) is added to the
mass in such proportion as to leave approximately (subject to the
principle laid down in the 4th paragraph hereof) for every 71 parts
of phosphoric acid 28 parts of lime or 20 parts of calcium. The
evaporation and drying is continued the temperature being regulated as
may be necessary. The dry product will be an artificial manure con-
taining a high percentage of phosphate of lime in a rapidly soluble
condition.
In some cases instead of employing sulphuric acid for combining with
the desired portion of the lime or calcium cither of the alkalies
(ammonia or. potash or soda) or their salts in any more or less pure
condition, or any mixtures thereof, either separately or in conjunction
with sulphuric acid may be employed. The dry product will then
contain in addition to the phosphate of lime (in the desired condition)
salts of the alkali or alkalies, varying according to the alkali or alkaline
salts or mixtures thereof used, and the proportion in which they have
been employed.
The liquor at any stage of the evaporation may also be intermixed
with any of the forms of phosphate of lime, varying the proportions
according to the character and composition desired for the product."
In like manner the solution of any of the forms of phosphate of lime
(obtained as described in the paragraph hereof numbered 1) is trans-
ferred direct to the evaporating furnace, and the relative proportion
of the lime or calcium to the phosphoric acid having been ascertained
it is treated at any stage of the evaporation with sulphuric acid, or
either of the alkalies or alkaline salts above mentioned or any mixtures
thereof regulating the proportions employed according to the character
and composition desired for the product.
:
3. On the same principle phosphoric acid of any degree of con-
centration (intermixed with hydrochloric acid) is obtained according to
the number of times the acid liquor is caused to dissolve any of the:
before-mentioned forms of phosphate of time or any mixture thereof, and
is subsequently mixed with sulphuric acid (in any more or less dilute
condition) in such proportion as to combine with the whole of the lime
་

page_text: or calcium present, the relative proportion of the phosphoric acid to
the hydrochloric acid being increased with each solution and pre-
cipitation. The sulphate of lime is separated as before described after
cach precipitation and may be washed with water. The solution of
phosphoric acid thus obtained and which is of any desired strength, is
mixed at any stage of or without evaporation with any of the before-
named forms of phosphate of lime or either of the alkalies or alkaline
salts or any mixtures thereof varying the proportion of the mixture
according to the character and composition desired for the product, and,
if required, the mixture may be subsequently evaporated or dried by
any suitable means. When the phosphoric acid is made to react on any
mixtures of the alkalies or alkaline salts with either of the forms of
phosphate of lime, the phosphoric acid is by preference first made to
decompose or combine with the alkaline salts or the alkalies employed,
and the resulting mixture then made to act upon the phosphate of lime
employed.
4. The character and composition of the products are also regulated
on the same principle by the proportion in which the sulphuric acid is
employed, the quantity added varying according as more or less of
the lime or calcium is desired to be combined with it, and also the a
number of times the solution of the phosphate of lime is precipitated
by sulphuric acid and the resulting acid liquor subsequently made to
dissolve more of the phosphate of lime. In some cases the solutions
arc evaporated and dried, either without the addition or with the
addition of more or less of sulphuric acid, or of the alkalics or alkaline
salts or any mixtures thereof (as set forth in the paragraph hereof
numbered 2), as may be desired, or they may be mixed in the desired
proportion with the solutions prior to being conveyed to the evaporating
furnaces, and either with or without filtration or separation of the
precipitate.
By the before-mentioned means phosphates of the alkalics or
phosphate of lime of any degree of solubility are or is obtained, either
separate or intermixed in any proportion and of such character and
composition as may be wished by the manufacturer, and the same
may in some cases be purified by solution in water and subsequent a
evaporation.

page_text: Die Comitions of the Letters atent,.
filed by the said Benjamin. Tanner in the Great Seal Patent Office
on the 2nd December 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
TANNER, F.C.S., of North Strand, Dublin, Ireland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of June, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Benjamin Tanner, Her special license
that I, the said Benjamin Tanner, my executors, administrators, and
assigns, or such others as I, the said Benjamin Tanner, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN THE TREATMENT OF PHOSPHATES OF LIME, AMD IN THE PRODUCTION OF
VALUABLE PRODUCTS THEREBY," upon the condition (amongst others) that
I, the said Benjamin Tanner, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Benjamin Tanner, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, that is to say :-

page_text: paragraphs detailing the processes employed in carrying out my said In-
vention are numbered consecutively.
1. Any of the ordinary forms of phosphate of lime of commerce (such
as phosphorites, coprolites, apatite, phosphatic guanos, bone ash, or
animal charcoal) or any form of precipitated phosphate of lime, or any
other form or combination of phosphate of lime, or any mixtures thereof,
is or are treated with hydrochloric acid, either in the gaseous or liquid
condition, and either with or without the assistance of heat. By pre-
ference hydrochloric acid of 15° to 20° Twaddell's hydrometer, is
employed for this purpose. Solutions of any of the before-named
phosphates of lime, or any mixtures thereof, are obtained by passing
hydrochloric acid of any desired strength and temperature into any
convenient arrangement of tanks suitable for allowing the acid to pass
into, over, or through the phosphate to be operated upon. This can be
conveniently done by an arrangement of tanks similar to those adopted
for lixiviating "black ball," as well understood. In practice the tanks
are charged with the phosphate of lime to be worked in any more or less
divided condition, but it is found that pieces of the size of a walnut or
of broken "road stone" are well adapted for the purpose, as they allow
free passage for the acid. The hydrochloric acid is, by preference,
conveyed to a false bottom in the tank, over which the phosphate is
placed. From thence it percolates upwards through the phosphate,
dissolving and becoming more or less charged with it in its passage. It
is then conveyed to the bottom of the next tank and again made to
percolate upwards through the phosphate; this is repeated as often as
desired. But a tank with four cells or subdivisions is found to work
very satisfactorily, and to allow of a regular flow of liquor charged with
the phosphate being taken off for subsequent treatment. The same
results can be obtained by reversing the current so that the acid passes
downwards through the phosphate, or by passing the hydrochloric acid.
in a gaseous condition through the phosphate placed in a suitably con-
structed apparatus, as for example, the ordinary condensing tower, or a
slight modification thereof; at the same time either allowing water or
a weak solution of phosphate to percolate around or through the
phosphate of lime whilst it is being subjected to the action of the gas, or
by moistening the phosphate from time to time with water or a weak
solution, subsequently removing the soluble portion by washing, or by

page_text: any other suitable means for effecting the solution and removal of the
phosphate of lime. By these and similar arrangements solutions in
hydrochloric acid of any of the forms of phosphate of lime or any
mixtures thereof are obtained.
°
2. The solutions obtained as described in the preceding paragraph, or
either of them, are or is treated witli sulphuric acid (in any more or less
dilute condition) in such quantity as to combine with the whole or such
portion of the lime or calcium in the solution to be worked as may be
desired. By preference, and for the sake of example (but subject to the
principle laid down in paragraph hereof numbered 4), the sulphuric acid
is added in such quantity as will combine with the whole of the lime or
calcium present. This is accomplished by adding the sulphuric acid to
the solution of phosphate of lime in the proportion of 40 parts of
sulphuric acid (anhydrous) for every 28 parts of lime, or 20 parts of
calcium present in the solution to be worked. For example, 100 gallons
of the solution (containing 10 per cent. of lime) would be intermixed
with 143 pounds of anhydrous sulphuric acid, or its equivalent in any
more or less dilute condition. This can be conveniently effected in a
vessel fitted with rotating arms or by blowing air into the vessel, or by
other suitable means for keeping the solution in a state of agitation
during the mixing. By this treatment lime is precipitated. from the
solution in the form of sulphate of lime, which is separated from the
liquid portion by means of filtration, decantation, or otherwise, and
may be subsequently washed with water.
'
Having separated the sulphate of lime the liquid portion (containing
hydrochloric acid set free by the above treatment) is again employed
as a solvent for any of the before-named forms of phosphate of lime or
any mixture thereof, by cither of the methods set forth in paragraph
hereof numbered 1, and the resulting solution is again treated with
sulphuric acid (of any desired strength) in the manner above named, so
as to combine (subject as above mentioned) with the whole of the lime
or calcium present in the solution. The sulphate of lime is again
removed from the liquid portion by filtration, decantation, or otherwise,
and may subsequently be washed with water. The liquid portion thus
obtained, and containing the hydrochloric acid again set free by the
above treatment, is again employed as a solvent for any of the before-
named forms of phosphate of lime or any mixtures thereof, as above
described.

page_text: Having ascertained by suitable tests the relative proportion of the
lime or calcium to the phosphoric acid in the resulting solution it is
evaporated in suitably constructed furnaces. If the lime or calcium be
in excess of the desired proportion then at any stage of the evaporation
(but by preference when the action of the phosphoric acid on the
chloride of calcium, and the evolution of hydrochloric acid are getting
sluggish) sulphuric acid of any desired strength is added to the mass in
such proportion as to leave approximately (subject to the principle
laid down in the 4th paragraph hereof) 28 hundredweights of lime or
20 hundredweights of calcium for every 71 hundredweights of phosphoric
acid present. The evaporation or drying is continued until the whole,
or as much as is desired of the chlorides present, is decomposed, and the
residue is as free from chlorine as. may be desired, or until hydrochloric
acid fumes cease to be evolved at the temperature employed. The
temperature is regulated so that (by preference) the mass is not exposed
(after it has become partially dried) to more than 280° Fahrenheit, when
dry heat is employed. When superheated steam or any mixture of
steam with hot air is used for this purpose a much higher temperature
may safely be employed, regulating the temperature so that it is
decreased as the proportion of hot air to the steam is increased.
In practice it will be found advantageous towards the end of the
process to pass a jet of steam into the furnace, as it will be found to
facilitate the completion of the reaction, and it is also desirable to avoid
allowing the mass to attain a higher temperature than from 250° to 280°
Fahrenheit. The dry product will be an artificial manure containing
a high per-centage of phosphate of lime in a rapidly soluble condition.
In some cases instead of employing sulphuric acid for combining with
the desired portion of the lime or calcium, either of the alkalies
(ammonia, or potash, or soda,) or their salts in any more or less pure
condition, or any mixtures thereof, either separately or conjointly with
sulphuric acid, may be added. The dry product will then contain in
addition to the phosphate of lime (in the desired condition) salts of the
alkali or alkalies varying according to the alkali, alkalics, or alkaline
salts or mixtures thereof used, and the proportion in which they have
been employed.
The liquor at any stage of the evaporation may also be intermixed

page_text: proportion employed according to the character and composition desired
for the product, as set forth in paragraph hereof numbered 4.
In like manner the solution of any of the forms of phosphate of lime
(obtained as described in paragraph hereof numbered 1) is transferred
direct to the evaporating furnace, and the relative proportion of the
lime or calcium to the phosphoric acid having been ascertained it is
treated at any stage of the evaporation with sulphuric acid, or either of
the alkalies or alkaline salts before named, or any mixture thereof,
regulating the proportion employed according to the character and
composition desired for the product, as set forth in paragraph hereof
numbered 4.
Το
3. On the same principle phosphoric acid of any degree of concen-
tration (intermixed with hydrochloric acid), is obtained according to
the number of times the acid liquor is made to dissolve any of the
before-named forms of phosphate of lime or any mixtures thereof, and
the resulting solution subsequently mixed with sulphuric acid (in any
more or less dilute condition) in such proportion as to combine with
the whole of the lime or calcium present in the solution.
accomplish this 143 pounds of anhydrous sulphuric acid or its equivalent
in any more or less dilute or pure condition, would be intermixed (as
before described), with 100 gallons of the solution, taking such solution
to contain 10 per cent. of lime, regulating the amount of sulphuric
acid employed according to its strength and also the per-centage of
lime or calcium contained in the solution to be worked, the relative
proportion of the phosphoric acid to the hydrochloric acid being in-
creased with each solution and precipitation. The sulphate of lime is
separated as before described, after each precipitation, and may be
washed with water. The solution of phosphoric acid thus obtained, and
which may be of any desired strength, is mixed at any stage of, or
without evaporation, with any of the before-named forms of phosphate
of lime, or either of the alkalies or alkaline salts, or any mixture
thereof, varying the proportion and composition of the mixture accord-
ing to the character and composition desired for the product, and if
required the mixture may be subsequently evaporated or dried by
suitable means. When the phosphoric acid is made to react on any
mixture of the alkalies or alkaline salts with either of the forms of
phosphate of lime, the phosphoric acid is, by preference, first made to
decompose or combine with the alkaline salts or the alkalies employed,

page_text: and the resulting mixture then made to act upon the phosphate of lime
employed..
4. The character and composition of the product are also regulated
on the same principle. 1st. By the proportion in which the sulphuric
acid is employed, the quantity being varied according as more or less
of the lime or calcium is desired to be combined with it. 2ndly. By
the number of times the solution of the phosphate of lime is mixed
with any desired quantity of sulphuric acid and the resulting acid
liquor subsequently made to dissolve more of the phosphate of lime,
each precipitation and subsequent solution varying the composition and
character of the product obtainable on evaporation. 3rdly. By abstain-
ing from, or by regulating the addition of sulphuric acid or of the
alkalies or alkaline salts or mixtures thereof to the mass in the
evaporating furnace, as in some cases the solutions are evaporated and
dried, cither with or without the addition of more or less of sulphuric
acid, or of the alkalies or alkaline salts or any mixtures thereof (in the
manner set forth in paragraph hereof numbered 2), as may be desired,
or they may be mixed in the desired proportion with the solution prior
to being conveyed to the evaporating furnaces, either with or without
filtration or separation of the precipitate. 4thly. By varying the
relative proportion of the phosphoric acid added to any of the forms of
phosphate of lime, or either of the alkalies or alkaline salts or any mixture
thereof (as set forth in paragraph hereof numbered 3), or vice versa.
ร
It will be obvious to any one conversant with chemical manu-
factures that where it is desired to have a product containing ammonia
as one of its constituents ammoniacal guanos may be treated by either of
the methods herein-before named for the treatment of any of the forms
of phosphate of lime or any mixtures thereof.
Hydrochloric acid gas given off in any of the before-named processes
may be conveyed away to any suitable condensing arrangement, by
which it is recovered, and may be subsequently again employed in the
processes.
By the before-mentioned means phosphates of any of the alkalies, or
phosphate of lime of any composition or degree of solubility, are or is
obtained, either separate or intermixed in any proportion, and of such
character and composition as may be wished by the manufacturer, and.
the same may, in some cases, be purified by solution in water and
subsequent evaporation.

page_text: And I would have it observed that the proportion of the substances
employed for the purposes of my said Invention are not in all cases
precisely such as are herein-before named, as such proportions may (as
will be well understood by persons conversant with the manufacture of
analogous chemical products), in some instances, be varied, according
to the state of materials used in regard to admixture of impurities
without departing from the principle of my said Invention.
Having thus declared and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I would observe
in conclusion that what I consider novel and original, and therefore
claim as constituting the Invention secured to me by the said herein-
before in part recited Letters Patent are,―
First. The production of the several products resulting from the
treatment of phosphates of lime, herein-before mentioned in the manner
and for the purposes herein-before described and set forth.
Secondly. The treatment of the prepared solutions (at any stage of
the evaporation) with sulphuric acid' or any of the alkalies or alkaline
salts or any mixtures thereof, in the manner herein-before described and
set forth.
And, Thirdly. The methods of treating solutions of phosphate of lime
in hydrochloric acid, so as to liberate, in whole or in part, such acid,
and the subsequent employment thereof as a solvent, substantially as
herein-before described and set forth, or any mere modifications thereof.
In witness whereof, I, the said Benjamin Tanner, have hereunto
set my hand and seal, this Twenty-eighth day of November, in
the year of our Lord One thousand eight hundred and seventy-
four.
Witness,
EDWARD PURDON,
23, Bachelors Walk,
Dublin.
BENJAMIN TANNER. (L.S.)