NEW OR IMPROVED MODES AND MEANS OF SMELTING THE IRON OF WASTE SLAGS AND OTHER SCORIA, AND UTILIZING THE IRON THEREFROM
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Thomas Thomson at the Office
of the Commissioners of Patents, with his Petition, on the 18th
November 1871.
I, THOMAS THOMSON, of the City of Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of the said
Invention for “NEW OR IMPROVED MODES AND MEANS OF SMELTING THE IRON OF
WASTE SLAGS AND OTHER SCORIA, AND UTILIZING THE IRON THEREFROM,” to be
as follows, that is to say :-
This said Invention consists of a new or improved mode and means,
(susceptible of some modifications to be herein-after specified) of
treating the slag, cinder, and such scoria, containing iron or oxide or salts
of iron, or the oxide or salts of manganese left in the treatment of iron or
iron ores from puddling and other furnaces used therefor, so as to extract
and utilize the iron contained in and frequently lost and thrown away
with such scoria. And the nature of this said Invention consists
substantially as follows:-Particularly in passing a stream or streams of
carbonaceous gas (or it may be of powdered carbon of charcoal or coal,
or of oils giving off carbon gases) into and through the said scoria or
oxide and salts of iron residues while in a melted state within a suitable

page_text: hollow heating hearth furnace or vessel, such as puddling furnaces, or
the vessels used for refining iron and steel with ducts, apertures, or
tuyers for the injection of the said carbon and gases so as to extract and
reduce the iron therein to a metallic state, either having a malleable
character ready for being forged into scrap blocks by itself, or for
mixing with other wrought iron, or of a cast iron character for mixing
with cast iron, or suitable for being used in the refining furnaces or
vessels for fine iron or for steel, and consists further in the modes and
means of performing or effecting the purposes of the said Invention.
The first and simplest of these consists in taking the said slags or
scoria (containing iron, or oxide, or salts of iron, or containing oxides or
salts of manganese,) and adding sufficient silica to enable and cause the
whole to fuse into a slag when heated; or when the said iron slags (to
be treated can be got) contain a large quantity of silicas it is only and
simply necessary to mix sufficient of the said oxide or salts of iron scoria
(to be treated) to enable the whole to be melted into a slag by heat;
then to extract and reduce the iron in the said molten charge or bath of
slag, a piece of wood or coal, or it may be other freely carbonaceous
burning and yielding substance is immersed, and by preference stirred in
it so as to blow the carbon evolved in gas and particles up through the
molten slag, when with the addition of a little lime to absorbe the silica
freed from the iron which is precipitated or thrown down (to the bottom
of the hearth or vessel) in the state of mineral malleable iron. The slag
containing the silicate of lime is then run off the top when the iron is
stirred, or "balled" up (as usual in puddling furnaces) and worked below
the hammer or in rolls into scrap or rough bars for the subsequent
preparation of malleable iron, or for mixing with other irons in the
refining of iron and steel.
Another or second means of producing and inserting the said carbon
in a gaseous or powdered state into the said molten iron slag, consists in
first distilling off the carbonaceous gas from coal or wood, shale, or other
carbonaceous substances or oils, and then blowing or injecting the said gas
from a receiver (by any ordinary suitable blowing or forcing machinery)
in a stream or streams through the said molten iron slags within the
hearth of the reducing or converting furnace, vessel, or crucible, used

page_text: or coal dust would also reduce and precipitate the iron in a molten
metallic state, as described in reference to the first simple mode, by the
immersion of wood or coal.
The oxides or salts of manganese (when contained in or used with the
scoria to be treated in the first operation of fusing the whole into an iron.
slag ready for the second operation of the process of forcing the carbon,
gas, or matters through them) may be converted into slags and then
mixed with the silicate of iron or iron slags to be treated when in
heating and smelting the whole to a slag, as before stated, it is found
that the manganese acts as a substitute for the deficiency of the carbon
in the iron produced by this means, herein-before described, and the iron
is thus extracted and reduced to a liquid state ready for being run off
from the furnace or vessel in the form of cast iron containing manganese
and a little carbon suitable for mixing with other irons for the making
and refining of steel.
A bath of molten cast iron in the bottom of the furnace or vessel,
having the slags to be treated placed over it in a liquid state, may also
be used for converting the iron in the latter, which when the carbon is
blown through it in the second manner described, the result obtained is
that the iron parts from the slags above and precipitates amongst the
liquid cast iron.
The iron thus made by this method of reduction, if extracted from
slags containing little impurities, is very good and valuable for mixing
with "speagle" for the making of steel, or with gray pig iron for
making refined pig iron.