IMPROVE- MENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1874

page_text: LETTERS PATENT to Henry Aitken, of Falkirk, in the County of
Stirling, North Britain, Coal Master, for the Invention of " IMPROVE-
MENTS IN THE MANUFACTURE OF IRON AND STEEL."
Sealed the 16th February 1875, and dated the 12th September 1874.
PROVISIONAL SPECIFICATION left by the said Henry Aitken at the
Office of the Commissioners of Patents, with his Petition, on the
12th September 1874.
-
I, HENRY AITKEN, of Falkirk, in the County of Stirling, North
Britain, Coal Master, do hereby declare the nature of the said Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL," to be as follows,
that is to say:—
This Invention which relates to improvements in the manufacture of
iron and steel, is a development of the Inventions for which Letters
Patent have been granted to James Henderson, and to Alfred Vincent

page_text: Newton, as a person to whom the said James Henderson had com-
municated certain of his aforesaid Inventions when residing abroad.
The Inventions referred to are those for which the following Letters
Patent have been granted, viz., Nos. 318, 1051, 1544, 2590, and 2940,
all of the year 1870; No. 688, 1871; and Nos. 554 and 2318, 1872.
According to the present Invention, the object of which is to remove
impurities from pig or crude iron so as to produce a superior cast iron,
malleable iron, or steel, the iron is cast over, around, upon, or among a
core or cores composed of fluor spar or fluorides and oxides, or over,
around, or upon cores formed of the other substances set forth in the
Specifications filed under the afore-mentioned Letters Patent, so that
the pig iron when cold contains the aforesaid core or cores.
The cores are produced by mixing together pulverised fluor spar or
fluorides and oxides with a mucilaginous cementing or adhesive
substance mixed therewith, such as glue, gum, lime, tarry, coaly, or
bituminous matter, and with or without fibrous matter such as hair,
which when dry cements the pulverised substances together into a mass.
These cores may be formed on bars of cast iron, and after being dried,
glazed, or hardened with heat are laid in the pig beds or moulds, into
which the iron is discharged from the blast furnace or cupola. When
cold the pig iron containing the afore-mentioned cores is broken up and
charged in the ordinary way of charging pig iron on the hearth of a
cupola, puddling, melting, or steel furnace, and thus the time and
labour of distributing the pulverized fluor spar or fluorides and oxides
over the furnace hearth as heretofore practised is avoided, the loss of
heat during the time of spreading the pulverised material and the
cooling of the furnace being also avoided.
In place of casting the pig iron with a core as herein-before described,
the fluor spar or fluorides and oxides or the other materials set forth in the
aforesaid Specifications, may be made into lumps or pieces by adhesive
matter, or glazed as before-mentioned and charged with the ordinary pig
iron on or into the furnace hearth, or alternately with the pig iron, or
on the bottom of the furnace, with the same advantages as those already
mentioned in the case of using it as a core in the pig iron. When the
pig iron melts the substances of which the aforesaid cores or lumps are
composed act with the impurities in the iron and remove them,

page_text: Under another mode of working this Invention the cores or lumps are
composed of carbonates, such as carbonates of iron or of lime, which
when the iron melts give up carbonic acid, which acts with and removes
the impurities; or the cores may be composed of titaniferous iron ore
and lime, or of lime or limestone alone; or the cores may be made of
fluor spar or fluorides alone, or one or more of these substances may be
stratified with the iron, and a proportion of salt may be used or not, as
required, to act upon the sulphur. In place of using these substances
as cores or lumps they may be stratified alternately with or in the pig
iron.