IMPROVEMENTS IN PREPARING FIREPROOF MATERIAL FOR CONVERTERS AND FURNACE-LININGS
Year: 1879

page_text: LETTERS PATENT to Friedrich Carl Glaser, of 92, Lindenstrasse, Berlin, in the
Kingdom of Prussia and Empire of Germany, Engineer and Patent Agent, for
the Invention of "IMPROVEMENTS IN PREPARING FIREPROOF MATERIAL FOR
CONVERTERS AND FURNACE-LININGS." A communication from the Vereinigte
Koenigs & Laurahuette (United Kings and Laura Ironworks), of Koenigshuette,
Ober-Schlesien Prussia. Germany.
PROVISIONAL SPECIFICATION left by the said Friedrich Carl Glaser at
the Office of the Commissioners of Patents on the 25th November 1879.
FRIEDRICH CARL GLASER, of 92, Lindenstrasse, Berlin, in the Kingdom of Prussia
"IMPROVEMENTS IN
and Empire of Germany, Engineer and Patent Agent.
PREPARING FIREPROOF MATERIAL FOR CONVERTERS AND FURNACE-LININGS."
communication from the Vereinigte Koenigs & Laurahuette (United Kings and
Laura Ironworks), of Koenigshuette, Ober-Schlesien, Prussia, Germany.
A
This Invention relates to improvements in the production of fire proof material
for basic converter and furnace lining.
According to the methods hitherto known for producing basic bricks and twyers,
the shaped objects are exposed during several days to an intense white heat, in
consequence of which they shrink very much, crack, warp, and bend, so that in
this way it is not possible to produce with certainty and free from fault, objects of
particular shape and dimensions.
This disadvantage will be done away with by means of the process hereinafter
described, and it consists of the following:
Magnesian or ordinary lime stone is burnt during such time until it combines
together in such manner that after cooling in the atmosphere the burnt pieces do
not again fall apart and are not, or only with difficulty, slaked with water. Such
burnt lime, generally termed dead burnt lime, is now ground, and from the resulting
powder (fire clay) the basic bricks, tuyers, and other material is produced in the
following manner :-
The limestone employed for the manufacture is dead burnt in such a manner as

page_text: not to be slakeable with water, and ground to powder mixed with from 8 to 10
per cent. in weight of animal blood, and the bricks, twyers, and other objects are
formed of this composition under considerable pressure. The said objects are well
dried and used in an unburnt state.
When there is a less dead burnt lime, which is somewhat, although with difficulty
slakeable, it is, before the addition of the blood, either well slaked and allowed for
some time to settle, or it is previously worked up with tar, asphalt solution, linseed
oil, or with a drying liquid free from water, and allowed to rest until it is
moderately dry.
In using such a less dead burnt lime the pressed objects must also be burnt, but
it suffices to expose them to great heat for some hours, and in the case of smaller
objects even for only one hour, in order to make them perfectly hard and firm
without appreciable shrinkage, crankling, or warping, and so that they give a clear
ringing sound when struck.
For this manufacture the debris from well burnt basic furnace linings may
be used.
The important feature of this process consists in not using crude or merely
ordinarily burnt limestone, in which case the objects made are burnt for several
days at a white heat, but in first dead burning the limestone at a high heat and
producing from the said dead burnt lime the special lining material in the manner
described, by which the pressed bricks and twyers are either not burnt at all or only
for one or more hours, thus diminishing the great shrinkage and warping of the
objects formed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Carl Glaser in the Great Seal Patent Office on the 21st
May 1880.
FRIEDRICH CARL GLASER, of 92, Lindenstrasse, Berlin, in the Kingdom of Prussia
and Empire of Germany, Engineer and Patent Agent. "IMPROVEMENTS IN
PREPARING FIREPROOF MATERIAL FOR CONVERTERS AND FURNACE-LININGS." A
communication from the Vereinigte Koenigs & Laurahuette (United Kings and
Laura Ironworks), of Koenigshuette, Ober-Schlesien, Prussia, Germany.
This Invention relates to improvements in the production of fire proof material
for basic converters and furnace linings.
When basic bricks, twyers, and such like objects are made from crude dolomite
or lime stone, and then burnt until they become bound up in one firm hard body,
as in the "Thomas" process they shrink nearly to one half of their original volume,
in consequence of which they become distorted and bent and are generally flawed
or cracked by reason of the high temperature, so that it is very difficult to obtain
basic bricks, twyers, and similar objects in this manner, free from faults.
This drawback is avoided by the process the subject of this Invention, which
consists substantially in that I first burn the crude dolomite or other ordinary lime
stone (dead), and then make the basic bricks, twyers, and such like objects from the
powder of this dead burnt lime.
This powder has the property that objects which are made therefrom by the aid
of organic binding media, as tar, oil, blood, etcetera, become perfectly hard and firm
after being subjected for about two or three hours to an ordinary white heat without
further shrinking, whilst the binding media are entirely burnt.
The process is as follows:-
Dolomite or ordinary lime stone is burnt at a high white heat until it presents a
perfectly black and faintly glistening fracture, and after becoming cool does not fall
to pieces on exposure to the air.
The stones should not however present any signs of melting in the process.
The more foreign matters contained in the lime stone, the easier it is to dead
burn the same; the purer the limestone, the higher the temperature and the
greater the length of time necessary for the burning process.
When the lime contains too much foreign matter it molts before it is dead
burnt.
The temperature usually employed is 2000° "Celsius" and upwards, the time of
burning about from 12 to 36 hours. It is advisable to obtain beforehand a chemical
analysis, and to make trials by burning to ascertain the properties of the materials
at disposal.
Pure lime stone may also be mixed with a very impure lime stone or with silicate
of magnesia, cryolite or fluor-spar, or with chromate of iron and sulphate of magnesia
and similar fluxes.
In such a case lumps are made of the pulverized mixture with the application of
thinned animal blood, or a solution of green vitriol; they are dried and then dead
burnt.
The dead burnt stones are pulverized, the powder intimately mixed with tar, a
solution of bitumen, or with linseed oil boiled with some litharge, or with syrup,
and thereupon the respective bricks, twyers, and such like objects are pressed from
it, or the composition may be allowed to rest until it has become somewhat dry,
and then mixed with blood thickened by the addition of a little sulphuric acid.
Care must be taken that the composition be not too thick, as for the purpose of
pressing it should be rather light and not plastic.
The pressed objects are either then at once or one or two days after being

page_text: pressed, placed in the burning furnace or kiln for the purpose of effecting the
burning process.
For this finishing burning process the same temperature and duration of the
burning as is customary in the case of ordinary fire bricks suffices, as that such
basic bricks or twyers may if desired be also burnt at the same time in a kiln or
furnace with ordinary fire proof materials, if only care be taken that the acid and
basic materials do not come in contact with each other.
In the case of twyers, whole converter bottoms and large shaped stones, I enclose
the respective pressed objects within light sheet iron which must exactly fit to the
several forms, (for twyers and converter bottoms it is sufficient when the side
surfaces are encased) and the objects are burnt with their casings.
This process has for object the prevention of shrinkage in large or complex objects
during the first stage of burning when the objects are somewhat soft.
On the temperature being increased, the weak casing burns away when the
object under the process of burning has already been made firm by the heat.
In this manner large and difficultly shaped objects are produced without any
misshape, and with a perfectly clean exterior surface on which no traces of the
sheet iron are left.
The bricks, twyers, and such like articles produced in the manner described, are
after being burnt perfectly hard and firm without further liability to shrinkage,
therefore they do not warp or become distorted in shape. They are easily worked,
and as they have a somewhat rough surface similar to ordinary bricks, they may be
well bound together by mortar in the usual way.
In this process very great care must be taken that well dead burnt stones which
present a black faintly glistening fracture are used, and also that the powder shall
not by negligence become mixed with and be rendered impure by foreign matters;
if stones of exactly the same composition are used, but not sufficiently burnt, the
objects made therefrom fall to powder again upon subjection to the heat after the
binding media have burnt away.
Having now described and ascertained the nature of the Invention communicated
to me as aforesaid, and in what manner the same is or may be performed, what
I claim as secured to me by the herein before in part recited Letters Patent is,-
Firstly. The production of fireproof basic material for converters and furnace-
linings from a powder of so dead burnt lime, in the manner herein described.
Secondly. The finishing the burning of the articles made from a powder of such
dead burnt lime in a casing of sheet iron, substantially as specified.
In witness whereof, I, the said Friedrich Carl Glaser, have hereunto set my
hand and seal, this Eighteenth day of May, in the year of our Lord One
thousand eight hundred and eighty.
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