IMPROVEMENTS IN THE SMELTING OF IRON
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by William Alexander Lyttle at
the Office of the Commissioners of Patents, with his Petition, on the
31st October 1874.
I, WILLIAM ALEXANDER LYTTLE, of the Grove, Hammersmith, in the
County of Middlesex, Engineer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE SMELTING OF IRON," to be as
follows:-
:-
In making this application for Letters Patent I do so chiefly with the
view of more perfectly and perhaps more legally fortifying certain claims
made in the final Specification of my Letters Patent, Numbered 1560, of
this year entitled "Improvements in the Process and Apparatus for
Smelting Iron."
In that Specification it will be found stated that clay or hydraulic
lime or cement can be advantageously employed as the means of con-
solidating into solid masses a thoroughly incorporated mixture of iron
ore and lime without any admixture of reducing carbonaceous matter,
and the following is the method of carrying this process into effect :-
The use of clay described in the Specification of my Letters Patent,

page_text: Numbered 1560 aforesaid, as the means of consolidating the mixture of
powdered iron ore, lime, and fuel, required in the preparation of my
"triplex compound," is equally available for rendering feasible the
consolidation of a mixture of quicklime or chalk and crushed or
powdered iron ore, without any admixture of fuel in the consolidated
mass.
The fuel required for the reduction and smelting of this consolidated
mixture should be either wholly interstratified with the consolidated
lumps in the common blast furnace, in order that those lumps may be
smelted in the ordinary way, or part of the fuel may be interstratified
with the lumps, as reducing fuel only in the ore chamber of my
"duplex furnace," referred to in my said Patent, Numbered 1560, whilst
the remainder of the fuel is consumed in the fuel chamber of that
furnace for the production of the requisite smelting heat.
The great object of this incorporation of lime and ore with fluxing
clay, to which silica or silicates may be added if necessary, are to enable
the lime in a finely divided state and finely incorporated with the
crushed ore, to exercise its well known de-sulphurizing power with
the greatest effect; also to prevent the reduction of any silica which may
exist in the ore to silicon, which would combine with and injure the
iron, because the intermixed lime combines with the silica of the ore, so
as to form silicate of lime long before the heat has risen to the point
necessary for the deoxidation of the silica. Hydraulic lime or cement,
never before employed for such a purpose, may also be adopted as the
means of converting the crushed or powdered ore into a concrete, as
described in my Letters Patent, Numbered 749 of this year, entitled
Improvements in the Means and Apparatus for Smelting Iron," but
without the admixture of any carbonaceous matter. If the ore to be
smelted requires the addition of silicious matter for the formation of a
flux, such matter should be added in the form of clean sharp sand or
burned clay, commonly known as "ballast." Common lime may also be
intermixed with the hydraulic lime or cement if desired.
When the iron ore is of a soft clay-like consistency, as is frequently
the case with hæmatite ore, it is desirable to prepare it for consolidation
as a concrete by working it up in a pug mill with plastic clay and then a
calcining it. By this means it acquires the character of the burned clay
above referred to and affords a stronger concrete.

page_text: If lime is thoroughly incorporated with such ore and clay before the
mixture is burned the resulting burned product will possess the
character of the well known Portland cement, and no cement or
hydraulic lime will be required in addition. In order to secure this
hydraulic character to the mixture various proportions of lime and clay
will have to be employed, according to the amount of silica or alumina
in the ore, but the proportions must be regulated so as to keep as nearly
as possible to those observed in making Portland cement, which are
about two to three parts of lime to one part clay. The same treatment
may be adopted with any crushed or powdered iron ore..
The hydraulic and ferruginous coment thus produced may be crushed,
mixed with powdered fuel, and consolidated without any additional
hydraulic lime or cement into lumps of the concreted triplex compound,
specified in my aforesaid Patent, Numbered 749, of this year.