Improvements in and in the Method of Manufacture of Fertilizers.
Year: 1892

page_text: Date of Application, 10th May, 1892-Accepted, 11th June, 1892
COMPLETE SPECIFICATION.
Improvements in and in the Method of Manufacture of Fertilizers.
1, THOMAS MARSHALL SMITH, of 17 North Street, Baltimore, Maryland,
United States of America, Merchant, 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 :-
My invention relates particularly to the manufacture of fertilizer out of animal
substances such as leather scrap, hair, bones, muscles and horn. These are the
materials ordinarily used for such purposes, but my invention is also applicable to
any animal substance such as fish and substances of the same class.
The object of my invention is to secure in a product the greatest amount
of nitrogenous and other valuable volatile ingredients of which under the processes
heretofore used, a large proportion escapes. At the same time my object also is to
reduce animal substances to a condition fit for application to the soil as fertilizer,
this condition requiring that the substances shall be readily absorbed by the plants.
To this end it is not only necessary that the substances should be in a finely
pulverized condition, but also that their organic texture should be destroyed.
Herctofore such substances have been reduced to pulverised condition, or some at
least, by grinding but this does not destroy the organic texture and is in a greater
or less degree (varying with the different substances) difficult to accomplish.
Heretofore also, such supstances have been reduced to a liquid form by the
application of heat with moisture. A fertilizer in the liquid form is impracticable
to handle and to apply to the soil. If the liquid be evaporated down to a solid, the
evaporation at the same time carries off with the water, all or a great portion of the
valuable volatile ingredients.
My invention consists of a process of treating refuse animal substances and of
the product obtained by such treatment. The process consists in subjecting the
animal substances to heat in a closed vessel in the presence of water or some
equivalent liquid in a proportion to the amount of solid animal substances just
sufficient to reduce the mass to a solid form or condition, which, while hot is soft,
but readily hardens and becomes friable when cool. This process being carried on
in a closed vessel, none of the volatile elements can escape. The animal substances
being subjected to heat in the presence of water, and the heat being of sufficient
intensity and continued the proper length of time (as hereinafter explained)
destroys the texture and reduces the mass to homogeneous form without decom-
position. At the same time the amount of moisture remaining in the mass is so small
that when the mass is removed from the vessel in which it is treated and exposed
to the atmosphere and cooled it hardens and becomes friable. The amount of
water which escapes being inconsiderable, the hardening is effected without any, or
with very slight loss, of the volatile ingredients. In fact after repeated chemical
tests, I have found that the amount of nitrogenous substances obtainable from the
dry material, after the treatment above indicated, is practically the same as that
existing in the raw materials before the treatment. The vessel containing the
animal substances and the water being tight, there is no change in the amount of
moisture contained therein during the heating. The steam applied in the jacket
of the kettle or boiler gradually brings up the temperature to the desired point.
The aforesaid process may be performed in a closed jacketed vessel or boiler
with suitable steam pipe communicating with the space in the jacket and suitable
steam generator. The boiler should have a grate a little raised above the bottom
to sustain the crude material, separate from the water underneath. Application of
the heat generates steam which rises up through the crude materials. The water
and steam are retained in the boiler and the steam in the jacket is not permitted to

page_text: enter the boiler where the materials are. It being desirable for the best effect in
the use of the invention to apply a higher degree of heat than that applied by
steam at atmospheric pressure, the apparatus should be designed for the application
of steam in the jacket under a high pressure. Into this vessel or boiler I introduce
the animal substances, for example hair. If this substance is in ordinary condition
I first introduce into the boiler, water under the grate, the amount of water being
just sufficient to convert the solid animal substances, when hot, into a soft but not
liquid condition. The quantity of water necessary to reduce the substance
depends upon the amount of moisture contained in said substance, which can be
readily determined by skilled workmen. Material originally containing greater
amount of moisture necessarily requires less water in the boiler. I have found that
an amount equal to fifty gallons of water is sufficient for 2000 pounds of hair
having six per cent. of moisture with hair. When substances to be heated in the
vessel have in themselves a large percentage of moisture the amount placed under
the perforated bottom is proportionately diminished. Slight variation would not
materially effect the produce so long as the amount of water is not so great as to
convert the product into a liquid on the one hand nor so little as to permit burning
on the other. A liquid condition would require boiling in the open air in order to
reduce it to a solid, and the boiling would expose, by reason of the circulation
thereby caused, all the particles to the atmosphere and would expel,, with the
moisture, the greater part of the volatile ingredients of the animal substances.
Steam pressure for the purpose above named, of 60 to 80 pounds per square inch, is
sufficient to reduce the crude material to the required soft, solid or pasty form, in
about 20 or 30 minutes. A higher pressure and heat may be used to hasten the
process, but it must not be so high as to cause decomposition of the animal sub-
stances under treatment. When the substances have been treated as above explained,
they are dumped upon the floor in a cohesive mass which will spread slightly
and soon become cool and pulverisable.
When hair, scraps of hide or leather etc. are so treated the product retains all the
original albumenoids and nitrogenous ingredients, and has this special mark of
distinction that it is not hard like glue and when pulverized the particles are soft
and is ready for assimilation by plants. Hair so treated retains at first something
of its original form, but crumbles readily.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is;-
1. In the manufacture of fertilizers, the improvement which consists in first
placing animal substances within a suitable vessel with a definite amount of water
(sufficient only to reduce said materials to a soft or pasty mass while hot); then
closing said vessel, and subjecting the contents thereof to the action of heat until
the texture of the crude material has been destroyed and the material has been
reduced to a mass soft while hot and brittle and pulverisable substantially without
further desiccation when cold, as and for the purpose set forth.
2. An improved fertilizer consisting of animal substances such as hair, reduced
to a soft friable condition and retaining substantially all its original elements
substantially as set forth.
Dated this Ninth day of May 1892.
SLOAN & LLOYD BARNES,
Castle Street, Liverpool, Agents for the Applicant.