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Патент USA US3079279

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Patented Feb. 26, 1963
PR‘SCESS FGR TEE 3,679,266
Andre Galy,
Grenoble, France, assignor to Pechiney,
Compagnie de Produits (Ihirniques et Electroinetel
lurgiques, Parts, France, a corporation of France
No Drawing. Filed July 7, 1959, Ser. No. 825,409
manufacture of refractory and insulating elements ac
cording to the invention; while this process, which is
described below, is the preferred procedure, it is not given
by way of limitation but only by way of example.
By mixing at a high temperature of the
C., there is prepared a ?ne water suspension of a com
Claims priority, application France July 18, 1958
Claims. (Cl. 106-56)
limitation, starch, 1
glue, etc., or of mixtures of such compounds.
The present invention, which is the result of ap 10 suspension, there is added an amount of porousT0solid
compounds such as, and without
plicant’s researches, relates to a new refractory and in
limitation‘, cellulose
derivatives, for example, wood chips,
sulating material and, more particularly, to a process for
straw, cellulose
There is obtained
in this Way, a pasty mixture which is very viscous at the
It is already known to classify refractory materials 15 mixing temperature and which tends to solidify on cool
to room temperature.
according to their chemical composition into
((1) Acid products, among which are included clay
The mixture, constituted of a porous solid skeleton
and siliceous, etc. compounds;
(/2) Basic products, which include magnesia, dolomite,
20 ‘,
(c) Amphoteric
corundum; and lastly
zirconia, etc. ;
(d) Neutral substances, such as carbon and chromite.
It is known, for example, to make refractories having
an amorphous or graphitic carbon base by
mixing clays
with bituminous or tar derivatives.
It is also known that the basic characteristics of every
progressively raised
C. and higher, preferably
in the neighborhood toof 490°
1200'0 C. Such heating
refractory material are its porosity, pyroscopic resistance,
can be
mechanical strength, chemical corrosion, etc.
Lastly, it is known that the refractory materials play a
role in the technology of furnaces ‘and metal
lurgical apparatus.
invention, the temperature is
' ‘However, to applicant’s knowledge, there does not exist
raised a few tens degrees
per hour and,
at present any refractory or insulating material capable
more particularly, about 20 degrees per
of withstanding temperatures equal to or higher than 35 hour.
1800“ C., or even 1500° C., in the presence of carbon
The constituents of the mixture are then totally coked
and under a vacuum.
and the refractory and insulating elements obtained in
this manner are progressively cooled.
The present invention has for its object a refractory
and, moreover, an‘ insulating material capable of with 40 However, if the maximum heating temperature has
standing without damage temperatures higher than 1800°
‘been only of the order of 1200° C. then, there still re
C. at normal pressure, or 1500“ C. under a vacuum in a
mains in the elements, besides carbon, a small quantity—
reducing or neutral atmosphere. The material of the
of the order of a few percent~of alkaline ashes originat
present invention is constituted of pure porous carbon.
ing from the starting products. In order to remove these
ashes completely, it is necessary to raise the temperature
facturing such a product and its applications.
of the elements above 1200” C. and preferably, in the
neighborhood of 1700° to 1800° C.
The other objects of the invention will be disclosed
in the course of the following description.
According to a preferred embodiment of the invention,
Applicant has discovered a new
the elements are allowed to cool progressively and slow
outstanding pyroscopic and chemical re 50 ly from‘ about 1200” C.—which is the temperature at
tained in the course of ?rst heating~to a temperature
sistance, the following remarkable characteristics: low
density, below 0.4 and close to 0.25; low thermal con
below 400 or 300°
again heated, under
ductivity, of the order
few tenths of a kilocalory
vacuum, to a temperature of the order of 1700°~l800°
per square meter of surface, per meter thickness, per de~
C. This second treatment has for its purpose ?rst, to
remove the ashes and,
a thermal con
than 10 kg./cm.2; and, ?nally, easy workability and ap
strength of the elements.
The following examples, which are in no way given
by way of limitation, will illustrate the process for ob
taining the refractory and insulating material of the pres
plication, as it can be machined by simple tools suitable
ent invention.
for wood and converted to any desired shape.
Applicant’s researches have established that the said
product can be obtained by heating to high temperatures,
above 400° C., and preferably of the order of 1200” C.
Example 1
In a mixer provided with a heating device and ?tted
with temperature controls, there are introduced 200 liters
the order of 250 kg.) beet sugar molasses contain
bohydrate base,' such
as oses, holosides, heterosides, cellu 65 ing about
lose, etc.,
50% water. Mixing is effected for one half
hour at 120° C.; the evaporated water amounts to about
and having a carbohydrate base, such as oses, holosides,
50% of the initial water content.
heterosides, polyosides such as cellulose, stare , vegetable
There is then introduced 75 kg. chips, for example,
gums (gum of wood, gum arabic, gum of cherry wood)
of a resinous wood, produced by a planer and which have
etc. and/or proteins, such as gelatins, glues.
and higher, a mixture of solid compounds having a car
Applicant has also developed a process for the
been preliminarily screened on 5 to 20 mm. sieves in
order to retain only chips of a size between these two
dimensions. The mixture of chips and molasses is
re'ierlsiaee '}
> ‘They are then submitted to a second‘ treatment which
raises their temperature to 1800‘ C. under a high ,vacu-~
_ stirred ‘in the same manner for one hali.._hourl at 120° C.
There is then obtained a very viscous'paste which be
During this treatment, they are converted to pure
‘,"dé'privedo? ashes, and‘ lose 4% to 5% of their
comes almost solid if it be again allowed: to attain room ‘
This .paste is poured into ?re‘clay shells; (pipes) of
about 6 liters capacity-and is slightly tampedwith a'prés
sure of about 200 g./Crn.2.
. ‘_
'l r
5; weight.
,The.,character_istics ‘of’ the refractory and insulating
1 ‘bricks obtained inthis manner are substantially identical
with those oflthejbricks' obtained according to Example 1.
‘ '
, -_Ar'n'o‘ng_"thetrionaoitidizing, i.e. reducing or neutral, at
are then piled up in the trucks oi‘.attunnelfiurnacetoi the ;-. j'mospheif‘es whichcan be used for carrying out the ?rst
heat treatment according to the present invention, are for '
Protection“, against‘ ‘ L the heating .
ceramiceiurnace type.’
unstance neutral ‘atmospheres such as rare gas: argon,v
gases is secured by means ofa layerlot powderedc
, vellum‘ ornitrogenior-reducing atmospheres such as: car--'
silica sand placed on the upper part1‘; " ' ' '-' i" _ _
_ v
‘About 50 shells (pipes) are filled in this
. be monoiriderhydrogenyor methane, natural gas, crack
The temperature is raised about 20, degrees per'jyh'ou
until it reaches 1100° to 1200“ C.;‘v coolih'gjislgth’en' car_;._, .
C. or below is reached. ‘
‘ _ -. ..
The bricks obtained‘ in this way are athengsdbmi‘
to a second treatment at a high vacuum,‘
’ p
‘ '
Thelterm: ~“oses” refer to natural; sugars such as: glu
cos'e, mannose,‘ galactose,~ fructose.
‘ 1? Process for making refractory heat insulating product
consisting substantially of carbon comprising the steps of:
Thermal conductivity--. About 0.5 kcaL/mFYmJ
. v V '3
";_ f (1/11.;
. ‘
The termf‘heterosides” refer to natural extracts such
.as‘‘: tanin, salicin, amygdalin.
‘The term“‘holosides’ as used in the present speci?ca
' The bricks ?nally produced possess thejfollowing? rha'rj'
‘1:20 '- .tion referl for instance to 'saccharose, lactose, maltose. ‘
change in <51;
_ . '
"l?micronand 10-millirneters otlmercury;
-~ .
Speci?c gravity _____ ...._ About 0.25,.
the neighborhood
of the
of orderof
litters-after‘ the
of their weight Without any substantial’,
>_ Thersecorid heat'treatrnentetovrernove ashes and heavy
-_-t'ars-'—-isl_carried out ‘in a vacuum which may vary ‘between
ried out at the same slow rateuntil a temperature (if-300
intimately mixing‘, at a temperature of about 100° C.,
7 particles ofa ‘porous solid substance consisting substan
Compressive strength _..}_ About 10 to 12 kg./cm.2.y . _ ’
Ashes; ______ __‘_____‘_. <0.2%.
3° tially era compound selected ‘from the group consisting
of oses, holosides, hetero‘sides, and polyosides, with a
liquid binder capable of forming a'gel consisting‘substan
’ These bricks are easily cut and "shaped with t'rife usual.
t-ially of an aqueous suspension-of a material selected
tools for wood. They ‘can be used ‘as refractory, andjine‘
from-.1 the group consisting of oses, holosides, heterosides,
sulating materials in the constructionfof industrial tur-'
naces, and/ or any metallurgicaliequipment orjth'e ‘like, 35 polyosides, gelatine, and glues, to form a pasty mixture at
vthemixing temperature of a porous solid skeleton thor
which require the use of relractory'or insulating prod=
:oughly- impregnated with the gel-forming binder; placing
ucts capable of withstanding temperatures higher than
thispasty mixture into molds corresponding to the shape
1800" C. at normal pressure in a neutral or reducing‘
atmosphere, for example, in the presence of carbon; ' of the desiredrefractory product; submitting this paste to
moreover,v they are‘ quite-adapted for work under a high‘ 40
vacuum and'at temperatures higher than 1500° vC.
Example '2
A manioc meal’ slurry is prepared by boiling a sus-,
pension of 10 kg. meal in 100 liters Water. ' This slurry
is introduced into a mixer in which there isralso added
a slight‘pressure of about l00~200 grams/cm.2 to thereby
iiisurethe-uniform ?lling ofthe entire mold without sub
stantially increasingrthe bulkdensity ofvthe mass; heating
the mixture progressively in anon-oxidizing atmosphere
up to a temperature of about 1200” C. vwhereby the pasty
mixture is coked and transformed into carbon.
‘ 2.", A process according to claim 1, wherein said prod
uct is‘ subsequently vprogressively heated in a vacuum to
100 kg. (that is, about.250 liters) edible pastes of the
a temperature range between about 1200D C. and about
commercial type, in the form of grooved cylinders hav
ing roughly,‘ the [following dimensions: a diameter of 50 ratio ‘0.
3. ,A process according to claim 1, wherein the heating
12-15 mm, a length of 50 mm; '
. _
is carried outprogressively so- as to raise the temperature
, The'mixture is stirred for about 20 to 30 minutes at a
temperature of the order of 40° to 60° C.v
oi the paste at the rate oft'about'i20° C. per hour.
i The resultant paste is then poured into sheet iron molds
4. A process according to claim 1, wherein the product
having the following dimensions: 33 X 17 X 9 cm. The 55 is‘co'oled to about 300° C. and subsequently progressively
paste is slightly tamped therein under a pressure of about
heated to a temperature up to 1800° C. l
100 to 200 .g./cm.2. The'molds containing the paste are
75. A process according to claim 1, 'wherein'the product
introduced into an electrically heated tunnel-furnace, the V
is progressively cooled to about 300° C. at the ‘rate of
‘ temperature of its hottest section being controlled to 400°
C. By the use or a mechanical conveyor belt, the inolds~
about 20*’. (3.. per hour, and subsequently progressively
to atemperature up to 1800‘? C.
advance in the ‘furnace. at a rate corresponding to a rise 60 heated
6. A refractory heat insulating product produced by the
in temperature of 20 to 25 degrees C. per hour. The
temperature of 400° C. is high enough to insure the col -
process of c1 aim
ctory heat insulating product produced by the
7. A refra
ing of the mixture, and is low enough to permit sweep
process of claim 2.
References Cited in the ?le of this patent '
ing of the furnace by .a current of air which‘ assists in
the removal of water and hydrocarbon vapors, liberated
from the bricks, without inducing‘ combustion.‘ ’
After cooling at the same rate as they. wereheated',
the bricks almost attain their ?nal shape. Their volume
has been reduced about 50%. ‘The dimensionsiare those
of standard bricks, 22 x 11 X 6 cm.
Nevertheless, these bricks have still retained some
heavy tars and the total amount of alkaline ashes con
tained in the initial products,
Pearce _______________ __ Nov. 1, 1921
.l-lamister _____________ .__ July 15, 1924
.Atkinson ____________ __ May 19, 1925
Harak __...._> _________ __ Aug. 23, 1932
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