IMPROVEMENTS IN THE TREATMENT OF IRON SLAG BY WHICH IT IS RENDERED SUITABLE FOR USE AS A MANURE
Year: 1878

page_text: LETTERS PATENT to William Pochin, of Salford, near Manchester, in the County
of Lancaster, for the Invention of "IMPROVEMENTS IN THE TREATMENT OF IRON
SLAG BY WHICH IT IS RENDERED SUITABLE FOR USE AS A MANURE."
Sealed the 28th March 1879, and dated the 24th October 1878.
PROVISIONAL SPECIFICATION left by the said William Pochin at the Office
of the Commissioners of Patents on the 24th October 1878.
WILLIAM POCHIN, of Salford, near Manchester, in the County of Lancaster.
IMPROVEMENTS IN THE TREATMENT OF IRON SLAG BY WHICH IT IS RENDERED
SUITABLE FOR USE AS A MANURE."
This Invention has for its object improvements in the treatment of iron slag by
which it is rendered suitable for use as a manure.
The slag which I employ is that obtained when iron is treated with lime in a
Bessemer converter or in a furnace in such manner as to separate phosphorus from
the iron.
This slag I crush to a powder, and in this state it has a manurial value, but to
concentrate the manure and to render it more active I proceed to remove the excess
of lime, and also the iron which the slag contains, which may be done by washing
with dilute hydrochloric acid. This having been done, I bring the phosphate con-
tained in the residue to the condition of superphosphate by the addition of acid,
by preference sulphuric acid, as when preparing superphosphate of lime from
coprolites. The manure thus prepared may be applied to the land as superphosphate
manures, and with like advantageous results.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Pochin in the Great Seal Patent Office on the 23rd April
1879.
WILLIAM-POCHIN, of Salford, near Manchester, in the County of Lancaster.
"IMPROVEMENTS IN THE TREATMENT OF IRON SLAG BY WHICH IT IS RENDERED
SUITABLE FOR USE AS A MANURE."
This Invention has for its object improvements in the treatment of iron slag by
which it is rendered suitable for use as a manure.
The slag which I employ is that obtained when iron is treated with lime--in-a
Bessemer converter or in a furnace in such manner as to separate phosphorus from
-the-iron.-This-slag Lcrush_to_a_powder, and in this state it has a manurial value,
but to concentrate the manure and to render it more active I proceed to remove the
excess of lime and also the iron which the slag contains.
I prefer to operate in the following manner :-The slag is first reduced to fino
powder, the lighter portion is then separated from the heavier by suspending the
powder in water and allowing the heavier portion to settle. The methods in
common use for washing ores may be resorted to for this purpose. The lighter
portion so obtained is treated with a small quantity of hydrochloric acid until effer-
vescence ceases. This can be then, used as manure either alone or in combination
with other fertilisers.
The heavier portion is treated in a closed vessel with hydrochloric acid, either
with or without heat, and the gas evolved is conducted into a lead or other suitable
chamber, and is there burnt. The products of combustion consist largely of
phosphoric acid. This is collected in a small quantity of water supplied to the
chamber and neutralized with lime or soda, or it is available as phosphoric
acid.
By a variety of known methods the phosphoric acid may be rendered available
as a manure. If lime be employed to precipitate it bone phosphate is obtained,
and after it has been collected I bring it to the condition of superphoshate by the
addition of acid, by preference sulphuric acid, as when preparing superphosphate of
lime from coprolites.
'
The manure thus prepared may be applied to the land as superphosphate manures
are now applied, and with like advantageous results.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I do not confine myself to
the exact details described, but I claim the production substantially as described of
products having manurial value from slag obtained when separating phosphorus
from cast iron by means of lime in a Bessemer converter or furnace.
In witness whereof, I, the said William Pochin, have hereunto set my hand
and seal, this Twenty-second day of April, in the year of our Lord One
thousand eight hundred and seventy-nine.
WILLIAM POCHIN. (L.S.)