IMPROVEMENTS IN THE TREATMENT OF PHOSPHATES OF ALUMINA, OR PHOSPHATES OF ALUMINA AND IRON For THE PURPOSE OF OBTAINING USEFUL SUBSTANCES THEREFROM.
Year: 1876

page_text: LETTERS PATENT to George Edward Davis, of Runcorn, in the County of
Chester, Analytical Chemist, and James Bennett Aitken, of Manchester, in the
County of Lancaster, for the Invention of "IMPROVEMENTS IN THE TREATMENT
OF PHOSPHATES OF ALUMINA, OR PHOSPHATES OF ALUMINA AND IRON For
THE PURPOSE OF OBTAINING USEFUL SUBSTANCES THEREFROM.'
"
1
PROVISIONAL SPECIFICATION left by the said George Edward Davis and
James Bennett Aitken at the Office of the Commissioners of Patents on the
19th October 1876.
GEORGE EDWARD DAVIS, of Runcorn, in the County of Chester, Analytical Chemist,
and JAMES BENNETT AITKEN, of Manchester, in the County of Lancaster.
"IM-
PROVEMENTS IN THE TREATMENT OF PHOSPHATES OF ALUMINA, OR PHOSPHATES OF
ALUMINA AND IRON FOR THE PURPOSE OF OBTAINING USEFUL SUBSTANCES THERE-
FROM."
Our Invention relates to the treatment of such natural phosphates as are now
obtained in the West Indies and in other places for the purpose mainly of obtaining
a soluble alkaline phosphate substantially free from alumina and iron, and which
may be used direct in any of the known applications or utilized for the production
of phosphate of lime and caustic soda or a soda salt by further treatment with
caustic lime, or hydrate of lime, or a lime salt; and for the purpose of obtaining
the alumina and iron in a state separate from the phosphoric compound in an
insoluble form readily separated from the alkaline phosphate and which may be
used for the manufacture of alums or alum cakes, or for the manufacture of salts
of alumina or of salts of alumina combined with the corresponding salts of soda,
potash, or ammonia, and consists in operating upon the aforesaid phosphate or
phosphates with a mixture of silica or silicates and an alkaline compound, and with
or without slack or small coal. Thus, we use a mixture of the aforesaid phosphates
with silica or a silicate, sulphate of soda or "salt cake," and slack or small coal, or
we use a mixture of the aforesaid phosphates with silica or a silicate and carbonate
of soda or caustic soda; or we use a mixture of the aforesaid phosphate with silicate of
soda, with or without silica and with or without carbonate of soda or caustic soda, as
may be found necessary from the composition of the mineral; or we use a mixture of
[Price 4d.]

page_text: the aforesaid phosphate with silicate of soda, with or without silica, and with or
without sulphate of soda or "salt cake," together with slack or small coal if it be
found necessary to use the aforesaid sulphate of soda or "salt cake," as may be
required from the composition of the mineral. Any one or more of the said mixtures
we heat until the decomposition is complete, and the mass being now lixiviated
the solution obtained is phosphate of soda substantially free from alumina and iron,
and there remains an insoluble aluminous compound or soda residue consisting
chiefly of silica, alumina, a portion of the soda, and salts of iron.
The gaseous products evolved during the heating process may be. condensed in
the usual manner, or directly utilized for the manufacture of sulphates by known
processes or for the production of sulphuric acid.
The insoluble aluminous compound or soda residue may be utilized direct by
treating it with suitable acids, or it may be piled into heaps and the iron sulphide
oxidized into sulphate, which being then washed out may be collected by suitable
means. The insoluble aluminous compound or soda residue, after the extraction of
the sulphate of iron, may be manufactured into soda alum or soda alum cake by
treatment with sulphuric acid, such as that obtained from the gaseous products
evolved from the mixture during the heating thereof, and dissolving out from the
silica and other insoluble matter the sulphate of alumina and soda, the solution of
which may be evaporated to dryness to form soda alum; or the aluminous com-
pound, after the extraction of the iron, may be heated with sulphuric acid, and if
necessary dried or furnaced in order to form soda alum cake.
The insoluble aluminous compound or soda residue may be treated with any
necessary acid either before or after extraction of the iron in order to form salts of
aluminia or salts of alumina and soda, which may be dissolved out from the silica
and other insoluble matters, or the silica and such other matters may remain with
the salts of alumina or of alumina and soda. As an alternative of the above-
mentioned processes the following method may be adopted:-The said phosphates
are treated with any of the above mixtures, but without the silica.or silicate and
a solution obtained by any usual method of phosphate of soda and aluminate of
soda. The silica or silicate is then added to the solution when the insoluble
aluminous compound or soda residue is obtained, the phosphate of soda remaining
in solution to be used as formerly described. In this case the greater portion of
the iron is left behind when the solution of phosphate of soda and aluminate of
soda is dissolved out, the insoluble compound or soda residue is therefore nearly
free from iron, and in this condition, however produced, would be valuable for
pottery and other purposes, or it may be washed and made into soda alum or soda
alum cake with sulphuric acid or into other salts of soda and alumina.
The phosphates of alumina, or alumina and iron, may be further utilized for the
production of phosphate of soda (differing, however, from the ordinary phosphate
of soda, but into which it may be converted by well-known means) and the
insoluble compound by heating a mixture of the said phosphates with silica or a
silicate, and either chloride of sodium, or common salt, or nitrate of soda, or a
mixture of both, with or without the presence of steam and air, or with or without
steam alone, hydrochloric acid, or nitric acid, or chlorine being evolved, and phosphate
of soda soluble, and the insoluble compound or soda residue formed likewise.
In the foregoing description soda only has been referred to, but it will be evident
that potash may be substituted therefor.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Edward Davis. and James Bennett Aitken in the Great Seal 50
Patent Office on the 18th April 1877.
GEORGE EDWARD DAVIS, of Runcorn, in the County of Chester, Analytical
Chemist, and JAMES BENNETT AITKEN, of Manchester, in the County of Lancaster,

page_text: "IMPROVEMENTS IN THE TREATMENT OF PHOSPHATES OF ALUMINA, AND PHOSPHATES
OF ALUMINA AND IRON FOR THE PURPOSE OF OBTAINING USEFUL SUBSTANCES
THEREFROM."
Our Invention relates to the treatment of phosphate of alumina or phosphates of
alumina and iron such as are obtainable in the West Indies and in other places, for
the purpose mainly of obtaining the phosphoric acid as an alkaline phosphate, and
the alumina and iron as an insoluble compound in a state easily separable from the
soluble phosphate.
The alkaline phosphate produced may be either a phosphate of soda or a
phosphate of potash, according to the alkali used, but in describing this Invention
it is more convenient to refer only to the compounds produced when sodium salts
are used, but all that relates to these compounds applies also to the compounds pro-
duced by using potassium salts which are equally applicable.
Our Invention consists in operating upon the aforesaid mineral phosphate or
phosphates, either calcined or uncalcined, with a mixture of silica or insoluble
silicates and a salt of sodium, and with or without slack or small coal, and all pre-
ferably in a state of fine division.
We preferably use a mixture of the mineral phosphate or phosphates with silica
or insoluble silicates and sulphate of soda or salt cake and slack or small coal; or
we use a mixture of the mineral phosphate or phosphates with silica or insoluble
silicates and sulphide of sodium or carbonate of soda or caustic soda; or we use a
mixture of the mineral phosphate or phosphates with silica or insoluble silicates and
any of the aforesaid sodium salts, separately or together, as may be found necessary
from the chemical composition of the mineral phosphate or phosphates to be operated
upon, and with or without slack or small coal, and in such quantities as will produce
a tri-basic phosphate of soda, and an insoluble double silicate of alumina & soda,
together with sulphide or oxide of iron, according to the per centage of phosphoric
acid, alumina, & iron the mineral phosphate or phosphates may contain.
Any one or more of the aforesaid mixtures we heat in a suitable apparatus (such
as the ordinary reverbatory or revolving black ash or salt cake furnaces used by
alkali manufacturers) until the required decomposition is complete and the mass
being lixiviated the solution obtained is tri-basic phosphate of soda, and there
remains an insoluble aluminous compound or soda residue consisting chiefly of silica,
alumina, a portion of the soda, and sulphide or oxide of iron; or the heated mass
may be allowed to cool and utilized without lixiviation for manure purposes.
Of all the afore-mentioned sodium salts we consider it more economical to use
sulphate of soda or salt cake, and when this salt of sodium is used the sulphurous
acid evolved during the heating process may be condensed in the usual manner by
any convenient means or directly utilized for the manufacture of sulphites, sulphates,
or sulphuric acid by known processes.
The tri-basic phosphate of soda dissolved out may be crystallised or used direct,
or converted into other forms of sodium phosphate and utilized by any of the
known applications of these salts; or utilized for the production of the phosphates
of the metals or the phosphates of the metals of the alkaline earths by precipitation,
and for the production of other salts of sodium, according to the acid or oxide com-
bined with the metal or alkaline earth employed, such as phosphate of lime and
caustic soda or carbonate of soda or other salt of sodium by treatment with caustic
lime or carbonate of lime or other calcium salt, but the methods or agents employed
in the utilization of the phosphate of soda form no part of our Invention.
The insoluble aluminous compound or soda residue, in whatever manner produced,
may be utilized by treating it direct with suitable acids when it will be found
useful for precipitating sewage and other foul liquids and for any other purposes to
which a crude salt of alumina or soda could be applied. When the insoluble
aluminous compound or soda residue contains sulphide of iron, the latter may be
oxidised into sulphate of iron, the copperas being washed out and collected by any
convenient method; and the remaining insoluble aluminous compound or soda
residue may be manufactured into soda alum or soda alum cake by treatment with

page_text: sulphuric acid, and dissolving out the sulphates of alumina and soda from the silica
and other insoluble matters to form soda alum, the solution of which may be
evaporated to dryness, or after treatment with sulphuric acid we evaporate the
whole mass to dryness and, if necessary, furnace it to form soda alum cake.
The insoluble aluminous compound or soda residue, either before or after the
extraction of the sulphide of iron, may be treated with any necessary acid in order
to form soluble salts of alumina and soda. These soluble salts may be dissolved
out from the silica and other insoluble matters and utilized as required, and when
the acid used is sulphuric the soluble salts may be manufactured into sulphates of
alumina and sulphates of soda, or manufactured into alum corresponding to the
alkali used, or the silica & other insoluble matters may remain mixed with the
soluble salts so formed and utilized as already described.
As an alternative of the afore-mentioned processes by which tri-basic phosphate
of soda and our insoluble aluminous compound or soda residue are produced, we
take the mixture of phosphate of soda & aluminate of soda produced by many
well known methods from phosphate of alumina or phosphates of alumina and iron,
and heat this mixture in a furnace or other suitable apparatus with silica or
insoluble silicates in quantities sufficient to produce our afore-mentioned double
silicate of alumina and soda and phosphate of soda. The insoluble aluminous
compound or soda residue may be separated from the phosphate of soda by lixivia-
tion, subsidence, filtration, or other well known methods, and utilized by the
processes herein-before mentioned; and being practically free from iron may be
used for the manufacture of porcelain and pottery ware, glass, and other articles.
The phosphates of alumina or phosphates of alumina and iron may be further
utilized for the production of phosphate of soda, and our insoluble aluminous
compound or soda residue by mixing the mineral phosphate or phosphates, either
calcined or uncalcined, with chloride of sodium or common salt and silica, or sand
(all preferably in a state of fine division) intimately in such quantities as will
produce a pyrophosphate or metaphosphate of soda, and a double silicate of alumina
and soda. This mixture we treat in cylinders or furnaces or other suitable
apparatus, or in cylinders supplemented by the use of furnaces or other suitable
apparatus, and at the same time pass a current of steam, or a current of steam
and air (in either case preferably superheated) through the mixture when hydro-
chloric acid, or a mixture of hydrochloric acid and chlorine will be evolved, and
there remains behind in the apparatus used a mixture of phosphate of soda and
a double silicate of alumina and soda, together with the iron or undecomposed
phosphate and common salt. This mixture may be lixiviated and treated as
already described when produced by the former methods herein explained, or the
heated inass may be allowed to cool and utilized without lixiviation for manure
purposes. The hydrochloric acid or chlorine may be condensed or absorbed in the
usual manner.
The waste sand from glass works we consider specially applicable for all these
processes, thus affording an opportunity of utilizing this now waste material.
To prevent any misunderstanding of the words or terms used in this description
of our Invention, we here state that the words used to describe the insoluble
material produced by any of the processes refer to the same manufactured article,
and that the terms insoluble "aluminous compound or soda residue" and double
"silicate of alumina & soda" are synonimous terms, both applying to the same
product in whatever manner produced.
We do not claim as any portion of this our Invention that portion of the process
whereby phosphate of soda may be converted into phosphate of lime and caustic
soda or carbonate of soda, but having ascertained and thus described the nature of
our said Invention and the manner in which the same is to be performed, we claim
as our Invention,―
Firstly. The processes of manufacture whereby we obtain a soluble phosphate of
soda or potash, and the insoluble double silicate of alumina and soda or potash, by
heating phosphate of alumina or phosphates of alumina and iron with silica o

page_text: insoluble silicates in conjunction with salts of sodium or potassium (and slack or
small coal when requisite), substantially as herein-before described.
Secondly. The application of the mixture of phosphate of soda or potash and the
insoluble double silicate of alumina, and soda, or potash, for manure purposes.
Thirdly. The application of the insoluble aluminous compound, or soda or potash
residue (that is to say, the double silicate of alumina & soda or potash) for the
manufacture of alumina and soda or potash, salts or alums, or alum cakes, sub-
stantially as herein-before described.
In witness whereof, we, the said George Edward Davis and James Bennett
Aitken, have herewith set our hand and seals, this Seventeenth day of
April, in the year of our Lord One thousand eight hundred and seventy-
seven
GEORGE EDWARD DAVIS. (L.S.)
JAMES BENNETT AITKEN. (L.S.)