AN IMPROVED MANUFACTURE OF REFRACTORY MATERIAL, COMPOUNDED OF LIMESTONE OR DOLOMITE, OR MIXTURES THEREOF, TOGETHER WITH OTHER SUBSTANCES APPLICABLE FOR FURNACE LININGS, CEMENT, BRICKS, CRUCIBLES, AND OTHER PURPOSES
Year: 1879

page_text: LETTERS PATENT to Ernst Friedrich Althans, of Breslau, in the German
Empire, for the Invention of "AN IMPROVED MANUFACTURE OF REFRACTORY
MATERIAL, COMPOUNDED OF LIMESTONE OR DOLOMITE, OR MIXTURES THEREOF,
TOGETHER WITH OTHER SUBSTANCES APPLICABLE FOR FURNACE LININGS,
CEMENT, BRICKS, CRUCIBLES, AND OTHER PURPOSES."
Sealed the 28th November 1879, and dated the 14th June 1879.
PROVISIONAL SPECIFICATION left by the said Ernst Friedrich Althans at
the Office of the Commissioners of Patents on the 14th June 1879.
ERNST FRIEDRICH ALTHANS, of Breslau, in the German Empire. "AN IMPROVED
MANUFACTURE OF REFRACTORY MATERIAL, COMPOUNDED OF LIMESTONE OR DOLO-
MITE, OR MIXTURES THEREOF, TOGETHER WITH OTHER SUBSTANCES APPLICABLE FOR
FURNACE LININGS, CEMENT, BRICKS, CRUCIBLES, AND OTHER PURPOSES."
According to the present Invention limestone or dolomite (as free as possible
from silicic acid) is burnt and pulverised, and then thoroughly mixed with a watery
solution of chloride of magnesium or chloride of calcium. After cooling the com-
pound is directly applied as a lining to furnaces, or is shaped into bricks, crucibles,
and the like, or it may be used as a cement. The quantity of the solution mixed
with the limestone or dolomite varies according to the nature of these substances
and the degree of consistency required for the particular use to which the compound
is to be applied.
The manufacture of bricks, crucibles, and other vessels with this compound is
effected in the same manner as with ordinary clay, the shaped articles being dried
and burnt. The material being hygroscopic the articles made therefrom should be
preserved from moisture as much as possible.
For forming or repairing linings for furnaces or Bessemer convertors the plastic
compound can be directly applied in layers, and burnt after drying and hardening.
According to a modification the pulverised limestone or dolomite, either burnt or
unburnt, is mixed with hydrochloric acid solution in the proper proportions, and
employed in the above described manner. According to another modification pure
limestone is mixed with dolomite or dolomitic limestone in the pulverised state
Prine Ad 1

page_text: until the compound contains from 2 to 3 per cent. of magnesia; it is then moistened
with such a quantity of chloride of magnesium solution as would constitute in the
dry state an addition of 3 to 4 per cent. of solid chloride of magnesium. This com-
pound is worked into a paste or mortar, and then applied as a furnace or convertor
lining, as before described. The lining thus prepared must first be dried slowly
and carefully by means of slightly heated air blast, then heated by a moderate fire,
and lastly heated to a high degree by means of a coke fire with air blast.
As furthermore the chlorine combinations of aluminium, iron, and manganese
when hented together with limestone or dolomite also produce chloride of calcium
and chloride of inagnesium, without affecting the refractory properties of the com-
pound by the presence of the bases that are forined; and as furthermore chloride
of potash frequently takes the place of the chlorides of the alkaline earths, it will
⚫ be evident that all such combinations of chlorine can be employed with the same
result in place of the chlorides of magnesium or of calcium in the above described
processes.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernst Friedrich Althans in the Great Seal Patent Office on the 3rd
December 1879.
ERNST FRIEDRICH ALTHANS, of Breslau, in the German Empire. "AN IMPROVED
MANUFACTURE OF REFRACTORY MATERIAL, COMPOUNDED OF LIMESTONE OR DOLO-
MITE, OR MIXTURES THEREOF, TOGETHER WITH OTHER SUBSTANCES APPLICABLE FOR
FURNACE LININGS, CEMENT, BRICKS, CRUCIBLES, AND OTHER PURPOSES."
According to this Invention limestone, marble, or chalk, dolomitic limestone, or
dolomite selected as free as possible from substances having acid reaction, such as
silicic acid, alumina, iron oxide, and other impurities, is ground to a fine powder,
over which is poured an aqueous solution of magnesium chloride, and the mass is
well mixed and kneaded to a plastic condition. This plastic mass is similar to a
potter's clay formed of clay and sand, as the adhesive magnesium chloride solution
in drying hardens to a glass like consistency, thus binding together the loose lime
or dolomitic powder or main body of the compound in a purely mechanical manner
to a solid mass, so that this can be stored in dry localities and used either burnt or,
preferably, unburnt as a refractory material.
At very high temperatures the sandstone like mass becomes fritted together to a
dark coloured lava like porous substance of a very hard and compact nature, with-
standing high temperatures perfectly. For ordinary building purposes in which it
would be exposed to the atmosphere this substance is not applicable, because it
remains soluble in water, and even in its fritted condition contains soluble magne-
sium chloride, and crumbles away in the open air. Bricks, tiles, crucibles, and
other vessels may be made of the material in the usual way, and dried and stored
if possible in an unburnt state, and applied to the construction of metallurgical

page_text: apparatus or furnaces, so that those portions which are not directly exposed to
heat may retain the carbonic acid of the limestone or dolomite, and not be affected
injuriously by the atmosphere. For building such bricks or tiles a mortar con-
sisting of the same plastic substances thinned down with water is used. In its
pasty condition the material can be used for lining furnaces or Bessemer convertors,
or for repairing such linings, it being applied in layers, stamped, and slowly dried,
and then gradually heated up to the degree required in working. The dolomite
employed should only contain a small admixture of magnesium carbonate, otherwise
unburnt limestone should be added to correct the proportion, as an excess of the
magnesium carbonate impairs the refractory qualities of the material. Pure lime-
stone, such as marble, might be employed, but the resulting mixture is less durable
in the absence of magnesium carbonate, which by fritting under the heat increases
the cohesion of the mass. Instead of dolomite, magnesite or artificial magnesium
carbonate can be added to the lime.
Instead of magnesium chloride, calcium chloride or hydrochloric acid, separately
or mixed in any proportions with each other or with the magnesium chloride, may
be used as binding material, but in such cases the proportion of magnesium car-
bonate should be correspondingly increased. Burnt limestone, dolomite, or
magnesite might obviously be added to the principal mass, consisting of limestone
and magnesium carbonate, producing under certain circumstances "sorels " cement,
but this is not to be recommended, as it renders difficult the working of the plastic
mass, and diminishes its durability under heat. It is essential to produce the
cohesion of the pulverulent main body under varying temperatures by means of a
cement acting as long as possible mechanically, which becomes gradually trans-
formed, first from a tough watery condition to a hard state, and then to a tough
fusible condition, so that during the expulsion of the carbonic acid from the lime-
stone, &c., the material does not break or crack, but when heated retains a tough
consistency.
As the chlorine compounds of aluminium, iron, and manganese when heated with
limestone or dolomite produce calcium or magnesium chlorides, whilst the separated
bases do not materially impair refractoriness, and as the alkaline chlorides in many
respects take the place of chlorides of the alkaline earths, these chlorine compounds
might obviously be used with some advantage in various proportions as substitutes
for part of the magnesium or calcium chloride in the above described compound.
In particular the alkaline chlorides might be used when it is desired to render the
material softer in the fire, or even fusible, as an addition of only 1 per cent. suffices
for this purpose.
In producing the refractory material, according to this Invention, the following
process and proportions will be found advantageous:
-
The main ingredient, ground very fine so as to pass through a sieve of about
20 meshes to the inch, is obtained by mixing very pure limestone, or marble, or
chalk with dolomite or dolomitic limestone, and a proportion of magnesium car-
bonate equal to about four per cent.
This mixture is moistened to a doughy consistence, such as will ball in the haud,
with a concentrated solution of magnesium chloride (which may be prepared from
the mother lye of salt), and the doughy mass being thoroughly kneaded is ready
for direct application as a lining of furnaces or metallurgical apparatus, or for
moulding bricks or other articles, as first above described. For 1000 lbs. of the
mixture are employed about 50 lbs. of the solid magnesium chloride of commerce.
For lining a converter the tuyere holes may be filled with wooden pegs during the
ramining of the bottom and the surrounding surface, or they may be ran.ned in
with the material, and afterwards bored out, or they may be formed in a separate
piece, dried, and placed in the bottom unburnt before ramming. The lining or
moulded articles should be slowly dried at a temperature of 280° to 300° Fahr., at
which they acquire sufficient hardness. If the material is too moist, bricks and
the like moulded from it are apt to become bellied at the sides in drying, and
require somewhat troublesome manipulation with a knife to rectify them, which

page_text: may be entirely avoided by proper moistening of the mass, in which case the bricks
undergo little or no change of form in drying, and they can readily be built with
their jointings of the material thinned as a mortar. They do not crack with long
firing, nor does the rammed material, the only effect being the production at the
exposed surfaces of a thin skin of cohesive glaze, behind which the material retains
its sandstone like structure. Bricks and the like articles can be burnt in the usual
way in kilns on a bed of burnt lime, but require a strong long continued heat, as
they are very imperfect conductors. These bricks are however not recommended
for building furnaces in preference to other material, partly on account of their
greater cost, partly on account of the difficulty of building them, but principally
because they suffer, as stated above, from exposure to the air. In the process recom.
mended above for the magnesium chloride, may be substituted in part or wholly
calcium chloride or hydrochloric acid, so long as the proportion of magnesium
carbonate in the main body is increased correspondingly. Dolomite or dolomitic
limestone containing even a small proportion of magnesium carbonate can be
employed without addition of lime in the manufacture of refractory material.
Having thus described the nature of the said Invention and in what manner the
same is to be performed, I claim,―
In the manufacture of refractory material applicable for furnaces, crucibles, and
metallurgical apparatus and structures, the use of hydrochloric acid, or of magnesium
and calcium chloride, or mixtures of these, with or without admixture of alkaline
chlorides, as the binding material for a compound of limestone, marble, or chalk,
and dolomite, either mixed or separately, as herein describe♪
In witness whereof, I, the said Ernst Friedrich d, have hereunto set
my hand and seal, this Twenty seventh day of November, in the year of
our Lord One thousand eight hundred and seventy nine.