Year: 1886

page_text: We ALPHONSE FOULD and PHILIPPE GENREAU both of Nancy in the Republic
of France, Engineers do hereby declare the nature of this invention to be as
follows:
.
This invention relates to the manufacture of refractory articles that are subjected
to high furnace heats, whether they are separate articles such as crucibles, or are
parts of furnace structures, such as bricks, tiles, tubes or linings.
.
Two classes of materials are employed, those of the one class forming the basic,
and those of the other class the agglomerating, material. In the former class are
quicklime, and magnesia, carefully calcined without excess of heat; also anhydrous
or dehydrated alumina, or mixtures of these materials, care being taken that, when
they are to be made up they should be quite free from carbonic acid and moisture.
The presence of small quantities of substances such as silica or iron oxide which
exist in the minerals employed for calcination is not injurious. The materials
employed for agglomerating are mixtures, approximately in the proportions of
their chemical equivalents, of calcium chloride 55 to 56 parts by weight with
28 parts of lime, or with 50 parts of carbonate of lime or with 53 parts of
carbonate of soda. In any of these mixtures there may be substituted for the
calcium chloride, a suitable equivalent of sodium or magnesium chloride, or. of
mixtures of these chlorides, care being taken to maintain a due proportion of
chlorine. Again, for the chlorides in whole or in part, certain fluorides may be
used such as calcium fluoride, or cryolite, which is a double fluoride of sodium and
aluminium, or other substances of the same character; also for carbonate of soda an
equivalent quantity of carbonate of potash may be used. Any of these mixtures
being made, it is fused and cast in the form of plates which when cool are broken
up into small fragments. If these fragments are not to be used at once they
should be carefully protected from moisture, and if they shew by efflorescence the
presence of moisture they should be again fused. About ten per cent of the
agglomerant fragments pulverised are then mixed with the basic material also
pulverised, and the mixture is moulded dry under such pressure as to render the

page_text: bricks, blocks or other articles moulded sufficiently coherent to be placed in the
baking oven or furnace, the bed of which should contain no silicious or other
matter capable of combining with the basic material at high temperature. After
three or four hours baking the articles are ready for use. Such of them as are
defective may be broken up and the material can be pulverised to be used again.
Linings, and other Articles Subjected to High Temperatures.
We, ALPHONSE FOULD and PHILIPPE GENREAU both of Nancy in the Republic
of France, Engineers 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:-
11 "
This invention relates to the manufacture of refractory articles that are subjected
to high furnace beats, whether they are separate articles such as crucibles or are
parts of furnace structures such as bricks, tiles, tubes or linings. According to our
invention we make such articles of a combination of refractory basic substances
such as quick lime, magnesia or alumina, and of certain compounds which we term
"agglomerants," to be hereinafter described, and which serve to bind together the
basic material under the action of heat to a hard and resisting mass.
The substances employed for the purposes of this invention are:
1, Quick lime, such as is obtained, by simple burning in the ordinary manner
without excess of heat from limestone, but so that it does not contain appreciable
quantities of either water or carbonic acid.
2, Magnesia, also in the anhydrous condition, and not containing appreciable
quantities of carbonic acid, such as may be obtained by suitable calcination, of
either carbonate of magnesia or of hydrate of magnesia.
3, Mixtures of these bases, lime and magnesia, which are obtained either directly
or by calcination, without excess of heat, of magnesian limestone or dolomites pro-
vided these two bases do not contain at the time of use, either water or carbonic
acid.
4, Alumina, either anhydrous or dehydrated.
5, A mixture of these several bases, also freed from water and carbonic acid by
suitable calcination.

page_text: These basic materials, in particular the lime and magnesia may be accompanied
without inconvenience by a certain quantity of argillaceous matter silica, and oxide
of iron such as occurs together with them in the natural rocks that are used. for
their production provided the basic elements, lime and magnesia, remain greatly
predominant.
We also prepare for the purposes of our invention, a second category of sub-
stances, consisting of artificial products or compounds which we designate by the
name agglomerants, as they serve to agglomerate and harden by suitable heating,
the various basic substances or mixtures thereof above mentioned.
For preparing these agglomerants we mix intimately in proportions correspond-.
ing to their chemical equivalents, or nearly so, the following ingredients.
One equivalent of chloride of calcium, or 55 parts by weight, with one equiva-
lent of lime, or 28 parts by weight, or one equivalent of calcium chloride 55 parts
by weight, with one equivalent of carbonate of lime, or 50 parts by weight.
Or again, one equivalent of calcium chloride, 55 parts, with one equivalent of
carbonate of soda 53 parts by weight.
In each of these mixtures the chloride of calcium can be replaced, equivalent for
equivalent, either by chloride of sodium or by chloride of magnesium or by a mix-
ture of these chlorides, whether binary or triple, provided that the total quantity of
chlorine remains substantially the same as in the first named compound.
We may also substitute for the chloride of calcium in the composition of the
agglomerants, equivalent for equivalent, either in whole or in part, fluoride of
calcium, eryolite, which is a double fluoride of sodium and aluminium, or any other
body of the same family, and the carbonate of soda may also be replaced wholly
or in part by an equivalent proportion of potash.
These mixtures are heated to the point of perfect fusion, and after casting them
in the form of slabs, they are broken up after cooling, into small pieces which are
then kept in hermetically closed vessels until required for use. Before using, the
substance is very finely pulverised, taking care first to ascertain that it has not
absorbed a notable quantity of moisture, in which case it is again melted down.
For the manufacture of the agglomerants as above described the ingredients are
melted down in iron crucibles; but when the fusion is difficult, as is the case with
the agglomerant formed with an equivalent of chloride of sodium, and an equiva-
lent of quick lime, the following method is employed.
The bed of a reverberatory furnace or gas furnace is covered with a strong sheet
iron plate resting on supports, and having its edges turned up to form a rim with
the exception of the charging opening, thus forming a sort of pan which is heated
to a red heat and into which is introduced the mixture of ingredients forming the
agglomerant.
;
Under the action of heat, this mass soon becomes covered with a crust, and when
it has become sufficiently heated it is carefully stirred all over, while the fire is
increased, whereby it will first become pasty and soon afterwards fluid, when it is.
removed by a rabble through the charging opening, being allowed to fall on a cast
iron floor, where it hardens into sheets which are broken up and ground.
The furnace is then charged with a fresh quantity and the above operation is
repeated..
For making bricks, slabs, pipes, crucibles and other refractory articles, we finely.
pulverise the first above described basic substances or mixtures thereof, which are
first re-calcined if found to contain an appreciable quantity of moisture or carbonic:
acid; we then intimately mix them with a certain proportion of one of the agglo-
merants, such proportion not to exceed 10 parts of the dry agglomerants for
100 parts of the basic anhydrous substances. The mixture is then pressed in
moulds, being filled in in successive layers and compressed, a final pressure being
applied after the mould is filled, whereby the mass becomes sufficiently coherent to
be removed from the mould and placed in the baking furnace.
The surface on which the moulded objects are placed in the furnace must not be.
of siliceous or acid composition such as would combine therewith at a high tempera-

page_text: ture, and we therefore make it of a basic material such as bricks of magnesia or of
other neutral matter such as retort carbon, or coke cut in slabs, or compressed coke
dust. The moulded objects should be placed at once in the baking furnace, as
exposure to the air should be avoided; they should therefore not be subjected first
to a drying process like other bricks &c, and as they are of anhydrous materials
they can at once be introduced into a highly heated furnace without danger of
deterioration by the sudden change of temperature. The hardening of the objects
is readily effected in less than three or four hours in a simple reverberatory furnace
or other furnace, even under direct action of the flame, but it is advisable that the
flame should not be too oxidizing when the surface on which the objects rest is of
carbonaceous material.
The moulded objects thus obtain a considerable degree of hardness, the edges
thereof being left very sharp. They can afterwards be preserved for a long time
in the air in a covered place, without deteriorating, notwithstanding the large
proportion of basic matter contained therein.
"
Any defective articles after baking can be pulverised and again treated and
moulded as described, so that there practically no loss in the manufacture.
The bricks and other objects produced as above described readily resist the
temperature of molten steel and are eminently of a refractory and basic nature:
The same mixtures of basic and agglomerant materials may be used for forming
pisé" structures of a refractory and basic nature in particular the beds of
metallurgical furnaces, by gradually building them up in layers of the form
required and then at once, baking them by means of the flames from a lateral
fire place. Similar refractory and basic objects may be produced by mixing the
primary basic materials directly with chlorides of sodium, calcium or magnesium,
or mixtures thereof, instead of with the agglomerant compounds described, taking
care that the proportion of chlorine compound does not much exceed eight per cent
of the weight of the anhydrous basic materials. It is preferable that these
chlorides should be in a dry condition, like the basic substances, and if they are
hydrated or in solution it is necessary to calcine the mixture to remove the
moisture, before moulding. This addition of chlorides can also be effected by
slaking the basic substances with solutions either simple or mixed, of the chlorides,
such solutions being either directly produced or consisting of residues of manu-
facturers, such as the mother liquors of saltworks or the calcium or sodium chloride
solutions resulting from the ammonia-soda process. But when this is done it is
necessary to remove the moisture by calcination before moulding and baking.
We greatly prefer however the first described method of preparing these
compounds by means of the agglomerants described, and in this mode of manu-
facture we have found it advantageous to use as the basic material, the mixtures of
lime and magnesia obtained by calcination without overheating, of the natural
rocks called dolomites, in particular the "Barrois" stone, these being mixed with
about eight per cent of their weight of a dry agglomerant. The said basic
materials may also be used when calcined at exceptionally high temperatures;
we do not however claim the use of these materials by themselves but only when
combined with the agglomerants or chlorides as above described, as a means of
hardening the basic substances and of obtaining refractory products of a more
compact and resisting nature than those made without these additions.
The moulded objects made of basic and refractory material according to our
above described invention are liable to shrink somewhat under a high degree of
heat; this may be diminished and even more or less entirely avoided by subjecting
the compound after, admixture of the agglomerant, but before moulding to a white
beat. For this purpose the compound is made into the form of small bricks or
balls, with a slight addition of petroleum; oil; or tar, sufficient for maintaining their
form, and is subjected to the requisite high degree of heat in a reverberatory
furnace, or in a gas cupola furnace; where the material will be made to shrink and
become very hard; it is then pulverised, and moulded as above described when it
will be found not, to shrink further to an appreciable extent,

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
:-
1. The herein described improved manufacture of refractory bricks, slabs, tubes,
crucibles, furnace linings, and other articles, consisting in mixing basic and
refractory bodies such as lime, magnesia and alumina with agglomerants and
subjecting the compound to a high heat whereby the basic materials will be bound
together so as to form a hard resisting mass.
2. The herein described manufacture of agglomerants composed of basic materials
with chlorides or fluorides, for use in combination with lime or magnesia or alumina,
or mixtures thereof, for the production of refractory articles such as bricks, tiles,
tubes, crucibles, furnace linings, and the like.
3. The use of chlorides of sodium, calcium or magnesium, either alone or mixed,
and either anhydrous, hydrated or in solution, or of fluorides of calcium, double
fluoride of sodium and aluminium, or other bodies of the same family having
analogous properties for mixing with basic bodies such as lime, magnesia alumina
or mixtures of these and rendering them hard when subjected to heat for the
production of bricks and other objects substantially as herein described.
°
4. The use of refractory articles such as bricks, tiles, tubes, crucibles, furnace
linings and the like composed of basic bodies such as lime, magnesia and alumina
combined in the manner herein described with agglomerants or substances whereby
they will be rendered hard when prepared and subjected to heat, substantially as
set forth.
5. Constructing the beds of furnaces for baking the refractory articles referred
to in the preceding claims of carbonaceous material such as retort carbon, coke
cut in slabs or compressed coke dust, substantially as herein described.
Dated this 27th day of October 1886.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings, London, W.C.