IMPROVEMENTS IN THE MANUFACTURE OF STEEL FROM THE RESIDUUM OF PYRITE ROASTING FURNACES OR FROM IRON ORES
Year: 1882

page_text: A
PROVISIONAL SPECIFICATION left by William Thomas Whiteman at the
Office of the Commissioners of Patents on the 12th January 1882.
communication from abroad by Clément Martin of Bleyberg-Montzen in the
Kingdom of Belgium Analytical Chemist.
WILLIAM THOMAS WHITEMAN of No 7 Staple Inn in the County of Middlesex
Patent Agent.
"IMPROVEMENTS IN THE MANUFACTURE OF STEEL FROM THE
RESIDUUM OF PYRITE ROASTING FURNACES OR FROM IRON ORES." [A. communi-
cation from abroad by Clément Martin of Bleyberg-Montzen in the Kingdom of
Belgium Analytical Chemist.]
The importance of the manufacture of steel from the residuum of pyrite roasting
furnaces will be readily understood when it is considered that in France England
Belgium and Germany upwards of eight thousand tons of pyrites are annually
consumed producing after roasting in the furnaces upwards of five hundred and
twenty five thousand tons of peroxide of iron containing less than one per cent of
sulphur and which constitutes after being treated and purified according to this
Invention a very rich iron ore valueless for the manufacture of chemicals and which
has hitherto been neglected by iron manufacturers on account of its friability
which causes it to fall to a very fine powder and to obstruct the blast furnace
and especially on account of the metalloids it contains which render the iron
brittle.
The object of this Invention is to utilize the iron contained in the said residuum
by transforming it directly into steel of different degrees of carbonization and it
consists of the processes hereinafter described for the treatment purification and
reduction of the said residuum. When the residuum of the pyrite roasting furnaces
contains more than one per cent of sulphur it should be roasted again in presence
or not of oxidizing or desulphurizing agents to deprive it of its sulphur.
The residuum of the pyrite roasting furnaces containing less than one per cent of
sulphur is reduced to powder it is then placed upon sheet iron plates perforated
with holes of about one twenty fifth of an inch in diameter and is washed in a
trunk or vessel mounted upon fixed or shaking tables so as to enrich it or it may

page_text: be simply washed or cleansed in cases or tanks through which a stream of water is
caused to flow so as to enrich the residuum by depriving it of its earthy parts and
of those which are soluble in water.
The residuum or ore thus prepared is then mixed with coal or suitable carbon-
aceous matter in proportions varying according to the quantity of iron it contains
and the degree to which it is to be carbonized. To the mixture of ore and coal is
then added very unctuous clay and lime or any other like material capable of
forming a very fusible flux in proportions varying according to the physical state
and the chemical nature of the ore. The mixture or mass thus obtained is moistened
with water rendered alkaline or acid as required and then is converted into blocks
or cakes by being subjected to powerful hydraulic or other pressure in cylindrical or
other moulds. The said blocks or cakes having been dried are introduced into a
furnace hereinafter alluded to as the "calcinating and reducing furnace" in which
they are for a suitable time exposed to the influence of heat and a reducing
atmosphere. The iron contained in the said blocks or cakes under the influence of
the elevated temperature in the calcinating and reducing furnace is reduced a portion
of the lime combines with the sulphur and phosphorus whilst part of the unctuous
clay agglutinates and greatly hardens the mass and increases its density and parts
of the same are scorified with the gangue and lime forming with them a most
fusible scoria or slag which is removed to the melting furnace in which the next
operation is effected. The next operation is carried on in a melting furnace (or
other suitable apparatus) heated by ordinary fuel or in which the fuel is gasified
and used in the state of gas. The said furnace or apparatus the concave sole of
which has been previously charged with the highly fusible scoria or slag produced
in the calcinating and reducing furnace hereinbefore described is heated to a bright
red heat. The blocks or cakes also heated to a bright red heat are introduced into
the bath of melted scoria or slag by means of a self acting duct without any loss of
heat and sink into and are immersed in it by their own weight.
Under the influence of the elevated temperature of the furnace from which free
oxygen is excluded the reduction of the iron is completed whilst at the same time
it is carbonized by means of the surplus coal which has not served for the reduction.
The gangue forms with the lime and clay forming part of the blocks or cakes
introduced into the bath a basic scoria or slag which entirely covers the melted
metal and preserves it from oxidation and owing to the silica it contains and
also to its chemical properties it becomes a powerful agent of desulphuration and
dephosphoration.
When all the chemical reactions herein before described have been effected the
operation is terminated and the scoria or slag having been removed from the furnace
the steel is run into suitable ingot moulds for use as required.
The processes and operations hereinbefore described are also applicable to the
manufacture of steel from ordinary iron ores.