An improved Process of Treating Pnospnatic Earths and Rocks for the Manufacture of Fertilisers therefrom.
Year: 1886

page_text: Date of Application, 10th Apr., 1886.
Complete Left, 10th Jan., 1887.
Complete Accepted, 11th Feb., 1887.
An improved Process of Treating Pnospnatic Earths and Rocks for
the Manufacture of Fertilisers therefrom.
I NATHANIEL BARRETT POWTER, of Kingston Jamaica (and temporarily care of
Leaycroft and Co. of 120 Pearl Street New York in the County and State of New
York United States of America) Mining Superintendent, do hereby declare the
nature of this invention to be as follows:-
This Invention relates to a process for the treatment of rocks containing phosphates
of alumina for the utilization of the phosphoric acid in a condition for application to
land as a plant food. The rocks and earths composed of phosphates of iron and
alumina, or of phosphates of lime mixed with other combinations of iron and alumina,
thus far have not been successfully worked by others on a commercial scale as super-
phosphates not because any difficulty has been found in rendering the phosphoric acid
available as a plant food, as it has for many years been known that the application of
sulphuric or other acid would effect that purpose irrespective of the strength or degree
of concentration of the acid as long as there was sufficient of the acid to enter into
the proper chemical combination with the bases to set free the phosphoric acid, hence
it is of no consequence, as claimed by different parties, whether the acid is above 66°
or below 47° Beaume. The great difficulty in working the phosphatic rocks with iron
and alumina compounds has arisen from the fact that after the rocks have been
ground and treated with sulphuric acid the mass formed remained in a sticky,
gummy, state and would not dry, and could not be ground, nor was it in condition for
application to the land as a plant food.
My present Invention relates to the treatment of the class of rocks named, and
consists of a process whereby the formation of the sticky gummy mass is prevented
and by which the mass is rendered dry and granular. The object is to dissolve the
phosphoric acid from the alumina and make it unite with a lime or other alkaline base
so that it will be in a soluble and what is known in the trade here as the reverted
form, and to form the alumina into such a compound (as alum) that it will not
revent the mass from drying.

page_text: over.
The process is as follows;-Take 1000 lbs of ground rock and mix it with 800 lbs
of water, being by weight double the amount of alumina in the composition and some
The addition of this water to the mass before the addition of the sulphuric
acid (in contradistinction to mixing it with the sulphuric acid and then adding them
together in the mass) is important for by adding the sulphuric acid afterwards it causes
a great deal of heat when it comes in contact with the water and this heat being con-
temporaneous with the chemical reactions that take place it very quickly stimulates
the same.
These reactions are rendered possible by the large quantity of water used.
After the water is added to the ground mass then add 200 to 300 lbs of caustic lime
or other alkaline base such as soda or potash. This is added to enable the alumina,
sulphuric acid, water, and lime, to form alum in granulated form. This is a very
important feature of the process.
It is well known that alums are the double
sulphate of alumina and an alkaline base and when this salt crystallizes out of solution
a large quantity of water (24 parts) is absorbed and crystallized as water of crystal-
lization. This ensures the success of the drying operation. The addition of the lime
serves also to give the phosphoric acid that has been set free a base to fly to and
prevents it from reuniting with the alumina and becoming insoluble again. These
substances are then all mixed in a usual mixer (employed in all the fertilizer factories)
and stirred for about five minutes that the water may be well mixed with the alumina.
Then I add about 750 lbs of sulphuric acid of about 50° Beaume, or an equivalent
proportion and strength of acid, and stir for 15 minutes. The mass will then be
thoroughly mixed and can be poured out and allowed to dry naturally when it will
granulate in a fine powder and be fit to apply as a fertilizer and will analyze as
phosphate of lime, double sulphate of alumina and lime (or alum) and sulphate of
lime, the other ingredients being too small to note.
N. B. POWTER.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: An Improved Process of Treating Phosphatic Earths and Rocks for
the Manufacture of Fertilizers therefrom.
I, NATHANIEL BARRETT POWTER, of Kingston, Jamaica, West Indies, 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:-
This Invention relates to a process for the treatment of rocks containing phosphates
of alumina for the utilization of the phosphoric acid in a condition for application to
land as a plant food.
The rocks and earths composed of phosphates of iron and alumina, or of phosphates
of lime mixed with other combinations of iron and alumina, thus far have not been
successfully worked by others on a cominercial scale as super-phosphates; not because
any difficulty has been found in rendering the phosphoric acid available as a plant
food, as it has for many years been known that the application of sulphuric or other
acid would effect that purpose, irrespective of the strength or degree of concentration
of the acid, as long as there was sufficient of the acid to enter into the proper
chemical combination with the bases to set free the phosphoric acid, hence it is of no
consequence, as claimed by different parties, whether the acid is above 66° or below
47° Beaumé. The great difficulty in working the phosphatic rocks with iron and
alumina compounds has arisen from the fact that, after the rocks have been ground
and treated with sulphuric acid, the mass formed remained in a sticky, gummy, state,
and would not dry, and could not be ground, nor was it in condition for application to
the land as a plant food.
My present Invention relates to the treatment of the class of rocks named ; and
consists of a process whereby the formation of the sticky, gummy, mass is prevented
and by which the mass is rendered dry and granular. The object is to dissolve the
phosphoric acid from the alumina and make it unite with a lime or other alkaline base,
so that it will be in a soluble, and what is known in the trade here as the reverted
form, and to form the alumina into such a compound (as alum) that it will not prevent
the mass from drying.
The process is as follows;-Take 1,000 lbs of ground rock and mix it with 800 lbs
of water, being by weight double the amount of alumina in the composition and some
over. The addition of this water to the mass before the addition of the sulphuric
acid (in contradistinction to mixing it with the sulphuric acid and then adding them
together in the mass) is important, for by adding the sulphuric acid afterwards it
causes a great deal of heat when it comes in contact with the water, and, this heat
being contemporaneous with the chemical re-actions that take place, it very quickly
stimulates the same. These re-actions are rendered possible by the large quantity of
water used. After the water is added to the ground inass, then add 200 to 300 lbs of
caustic lime or other alkaline base, such as soda or potash. This is added to enable
the alumina, sulphuric acid, water, and lime, to form alum in granulated form. This
is a very important feature of the process. It is well known that alums are the
double sulphate of alumina and an alkaline base, and when this salt crystallizes out of

page_text: solution, a large quantity of water (24 parts) is absorbed and crystallized as water of
crystallization. This insures the success of the drying operation. The addition of the
lime serves also to give the phosphoric acid that has been set free, a base to fly to, and
prevents it from re-uniting with the alumina and becoming insoluble again. These
substances are then all mixed in a usual mixer (employed in all the fertilizer factories)
and stirred for about five minutes, that the water may be well mixed with the alumina.
Then I add about 750 lbs of sulphuric acid of about 50° Beaumé, or an equivalent
proportion and strength of acid and stir for fifteen minutes. The mass will then be
thoroughly mixed and can be poured out and allowed to dry naturally, when it will
granulate in a fine powder, and be fit to apply as a fertilizer, and will analyse as
phosphate of lime, double sulphate of alumina and lime (or alum) and sulphate of
lime, the other ingredients being too small to note.
Having now particularly described and ascertained the nature of the said Invention,
and in what manner in which the same is to be performed, I declare that what I
claim is
1. The herein described process of eliminating the phosporic acid from rock con-
taining phosphate of alumina, and rendering it available as a dry soluble fertilizing
phosphate; which consists in adding to the ground rock a proportion of water to
permit the reaction to take place, then adding separately, an alkaline base and
sulphuric acid whereby alum (a double salt of alumina and the alkaline base) is formed,
and the drying facilitated by the absorption of water as water of crystallization, and
a base given to the phosphoric acid to make a soluble phosphate, substantially as
described.
2. The herein described process of eliminating the phosphoric acid from rocks con-
taining phosphate of alumina, and rendering it available as a dry soluble fertilizing
phosphate which consists in adding to the ground rock double the amount (by
weight) of water that there is of alumina in the rock to permit the reaction to take
place, and then adding an alkaline base, and sulphuric acid, whereby alum (a double
salt of alumina and the alkaline base) is formed, and the drying facilitated by the
absorption of water as water of crystallization, and a base given to the phosphoric
acid to form a soluble phosphate, substantially as described.
3. The process herein described of eliminating the phosphoric acid from rocks con-
taining phosphate of alumina, and rendering it available as a dry soluble fertilizing
phosphate; which consists in adding to the ground rock the water before the addition
of the sulphuric acid and then adding an alkaline base, and sulphuric acid, whereby
the heat generated by the admixture of the acid and water is made contemporaneous
with the reaction between the ingredients and the following reaction stimulated ;
namely the formation of alum and concomitant absorption of water, and the union of
the phosphoric acid with the alkaline base to form a soluble phosphate, as set forth.
N. B. POWTER.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.