A Method for Obtaining Uniform Products from the Thomas' Convertor, Siemens' Open Hearth, or other Basic Furnaces
Year: 1890

page_text: Date of Application, 10th Mar., 1890-Accepted, 12th Apr., 1890
COMPLETE SPECIFICATION.
A Method for Obtaining Uniform Products from the Thomas'
Convertor, Siemens' Open Hearth, or other Basic Furnaces."
1 LEOPOLD PSZCZOLKA of Graz in the Province of Styria, Austria, Engineer do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and. ascertained in and by the following
statement:
The object of this invention is to prevent the variations arising in the quality of the
metal produced from all kinds of furnaces prepared in the basic manner.
This object is attained by causing the combinations of oxides of iron which are
formed in the metal produced as aforesaid to be scorified by the addition of substances
containing silicic acid Si O, instead of reducing them by carbon, manganese or silicon
or like additions, by which a soft iron is made therefrom which can never be brought
to the same degree of carbonization as the main part of the metal producing inequality
or variation in the products of basic processes especially in the harder qualities.
The process thus improved is carried out in the following manner.
The metal, fined in the usual manner is poured in a liquid state whilst keeping back
the basic slag as far as possible into a suitable caldron previously heated or capable of
being heated from without or into a cistern made of fire proof material, a chamber
or similar reservoir or into an ordinary oxidizing smelting furnace, or a smelting
furnace the hearth of which forms a movable caldron which can be moved into or
form the furnace and can be fastened to it and to the inlet channels by means of
suitable hydraulic apparatus. During, before, or after the pouring in there is then
added to the metal substances containing considerable quantity of silicic acid Si O, as
for instance slag, glass, quartz, feldspar or other minerals containing silicic acid or
artificial mixtures of Si O, with alkalies or alkaline earths or the like in a melted or
hard condition, warm or cold, in a powdered state or in pieces of optional size, these
substances containing Si O, being allowed to act upon the metal until it is found by
examination of samples taken one after the other that the darkening or colouring of
the slag due to the taking up of combinations of oxides of iron has become stationary.
In proportion to the greater or less oxydation of the iron bath the duration of the
above treatment may vary from one hour to less than one minute. The quantity of
the substances containing silicic acid to be added can be only determined by practice
as the quantity of the combinations of oxides of iron to be scorified varies according
to the raw material treated and according to the process employed the maximum in
any case, will however not exceed for every 100 parts by weight of metal bath 25 parts
of a substance containing 60% of silicic acid, 13 parts of a 70% substance 9 parts
of an 80% substance, 7 parts of a 90% substance. When from trials before made it
is known that the action of the silicic acid on the iron bath is completed there may
either be added to the metal in an optional manner the quantity of material for
recarbonization necessary which with this improved process will be somewhat less
than with the process employed hitherto, and the casting be proceeded with, or the
metal, freed from protoxyde and oxide may be caused to flow into an ordinary pan,
proceeding here only with the recarbonization and then be cast. With a metal bath
containing only small quantities of combinations of oxides of iron, one can pass the
decarburated and dephosphorized metal into a sump or into a case (open or closed
above) and allow it to flow off at the same time into the casting pan through an
outlet opening located in the lower part or at the bottom, the outflow can be regulated
by a fire proof stopper so that the sump or the case which contains the substance
containing silicic acid can be more or less filled at option. The substances for
recarbonization are then added in any desired way to the metal in the casting pan.
For producing malleable iron the decarburated and dephosphorized metal is freed
D77

page_text: from oxides according to the above described process and then cast without the
addition of any recarbonizing materials.
The metal so made is not brittle as is generally the case with cast iron produced
heretofore in the usual manner and is perfectly malleable.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is
"
The process or method consisting in the addition of substances containing large
proportions of silicic acid (Si O₂) to metals produced from or in any kind of basic
furnace as for instance from the "Thomas convertor or the "Siemens "basic open
hearth for the purpose of scorification of the oxides of iron formed in the metal, and
economy of recarbonizing material.
Dated this 10th day of March 1900
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.