Improvements in the Manufacture of Nitro-phosphates.
Year: 1898

page_text: [Communicated from abroad by LA SOCIÉTÉ COIGNET ET CIE. of 114, Boulevard
Magenta, Paris, in the Republic of France, Manufacturers.]
Improvements in the Manufacture of Nitro-phosphates.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
The object of the superphosphate industry is to render soluble in either water,
alkaline citrate of ammonia or phosphoric acid, tri-basic phosphates of lime,
whether these phosphates are mineral or bone phosphates. This is effected by the
mixture of these phosphates with sulphuric acid whereby sulphate of lime is formed,
which constitutes a paste absorbing phosphoric acid or acid phosphate of lime, and
upon this paste setting it may be pulverised and a dry powder obtained.
The invention consists in substituting nitric acid for sulphuric acid, by replacing
it equivalent for equivalent. The phosphoric acid is rendered soluble in precisely
the same manner as by the action of sulphuric acid. But whilst sulphuric acid
possesses no value as a fertiliser, nitric acid, which has then become nitrate of lime,
affords nitrogen to the plants in the form which has been shewn to produce the
greatest fertilising effect.
The product thus obtained is a liquid paste which I bring to a pulverulent
condition by one of the following methods; I may, for example, mix it with quarry
plaster or with plaster which is residue of manufacture, or it may be brought to a
pulverulent condition by a simple desiccating process, effected by heating in any
suitable manner. By heating to a moderate extent and during a period which
is not too long, no loss of nitric acid occurs; this takes place, however, if the
desiccating process is carried too far.
Another method consists in employing a mixture of nitric acid and sulphuric
acid. The sulphuric acid forms sulphate of lime which absorbs in the condition
of water of crystallisation the water in excess of the nitro-phosphate. For each
phosphate employed, the proportions of nitric and sulphuric acid necessary for
obtaining a dry product, may be readily ascertained. The resultant product is
then a mixture of nitrophosphate and of superphosphate. It is rather less active
than nitro-phosphate alone, but, as it is obtained in a dry state in the first instance,
it can be supplied for agricultural purposes at a cheaper rate.
These three methods of desiccation may be employed either separately or
together.
The product thus obtained in a pulverulent condition, which I term nitro-
phosphate, is a manure which is both nitrogenated and phosphated, and is far
superior to the superphosphate mixed with nitrate of soda which are manufactured

page_text: at the present time, as it contains no soda, which is useless and even harmful when
employed in agriculture.
Dated this lat dor of Vav 1808
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
mprovements in the Manufacture of Nitro-phosphates.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 object of the superphosphate industry is to render soluble in either water,
alkaline citrate of ammonia or phosphoric acid, tri-basic phosphates of lime,
whether these phosphates are mineral or bone phosphates. This is effected by the
mixture of these phosphates with sulphuric acid whereby sulphate of lime is formed,
which constitutes a paste absorbing phosphoric acid or acid phosphate of lime, and
upon this paste setting it may be pulverised and a dry powder obtained.
The invention consists in substituting nitric acid for sulphuric acid, by replacing
it equivalent for equivalent. The phosphoric acid is rendered soluble in precisely
the same manner as by the action of sulphuric acid. But whilst sulphuric acid
possesses no value as a fertiliser, nitric acid, which has then become nitrate of lime,
affords nitrogen to the plants in the form which has been shewn to produce the
greatest fertilising effect.
The product thus obtained is a liquid paste which I bring to a pulverulent
condition by one of the following methods: I may, for example, mix it with quarry
plaster that is, ordinary plaster similar to that employed in building operations,
being merely a second quality of plaster; or with waste industrial plaster, which
is a residue of manufacture, being a sulphate of lime obtained by precipitation in
certain industries e.g. in the phosphorous, stearine, and citric acid industries; or
the said product may be brought to a pulverulent condition by a simple desiccating
process, effected by heating in any suitable manner. The desiccation of the nitro
phosphate should be effected at 100° during two hours about. A desiccation
continued longer than this would occasion loss of nitric acid.
Another method consists in employing a mixture of nitric acid and sulphuric
acid. The sulphuric acid forms sulphate of lime which absorbs in the condition
of water of crystallisation the water in excess of the nitro-phosphate. For each
phosphate employed, the proportions of nitric and sulphuric acid necessary for
obtaining a dry product, may be readily ascertained. The resultant product is
then a mixture of nitrophosphate and of super-phosphate. It is rather less active
than nitro-phosphate alone, but, as it is obtained in a dry state in the first instance,
it can be supplied for agricultural purposes at a cheaper rate.
These three methods of desiccation may be employed either separately or
together.
The product thus obtained in a pulverulent condition, which I term nitro-
phosphate, is a manure which is both nitrogenated and phosphated, and is far
superior to the superphosphates mixed with nitrate of soda which are manufactured
at the present time, as it contains no soda, which is useless and even harmful when
employed in agriculture.

page_text: Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is:-
1. The treatment of phosphates of lime by means of nitric acid, with a view to
rendering the phosphoric acid soluble and to forming nitrate of lime.
2. As a novel product, the nitro-phosphate obtained by this process and intended
to serve as a manure for agricultural purposes.
3. The production of this manure in a pulverulent condition by mixing it with
plaster, or by desiccating it or finally by preparing it with a mixture of sulphuric
acid and nitric acid.
Dated this 28th day of November 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.