Note: Descriptions are shown in the official language in which they were submitted.
65367 ~ Z~ 3
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~HERMOINSULATING REFRACTORY MASS
ThiQ invention relates to a thermoin~ulatlng mas~ used for
thermic lnsulation of heating aggregates~
Thermoinsulating refractory masse~ are known representing
mixture~ of natural ceramic raw-materials,oxides,and light. fil-
ler~.Their refractoriness depends on the chemical composition
of the initial components in the mas~ while the low thermocon-
ductlvity i~ d~termined by the foaming agents contained therein.
It i~ known that the porosity of thermoinsulating refractory
maQ8e9 i8 obtained ~6 a re~ult of adding to their content of
diatomite,foamed vermiculi~e or perlite,pellets of preliminary~ ~ :
.
burned and foamed ceramic ma~ses or burnlng out organic addi-
~tive~/1,2/.
A d~sadvant ge of the known thermoin~ulat1ng mas~e.s con~-:
taining vermicullte or diatomlte ;i~ their limited refractori~
ness.~he operational temperature up to which they can be u~ed
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does not ~urpa~s 1100C /2/.
A draw-back of the known high refractory thermoinsulating mass
i9 its high thermic conductivity /1/.
The object of -thls invention is to provide a thermoin~ulating
refractory mass having simultaneou~ly a high refractoriness,resp.
a high working temperature and a low thermic conduc~ivity.
This object is achieved by ~ynthesizing a thermoinsulating re-
fractory mass comprising refractory clay and/or kaolin in amount
30 to 50 weight parts,liquid or solid water-soluble inorganic
bond in amount 5 to ~0 weight parts,water from 5 to 50 weight parts
and a burning out organic sub~tance pxeviously imbibed with liquid
inorganic bond i~ amount 50 to 180 volume parts per ~00 parts in
relation to the remaining mixture.
As burning out organic substances can be used husks o~ rice,
wheat,oats,barley or rye,saw~dusts or cellulo~e pulp or a mixture
of these substances.
The solid or liquid water-soluble inorganic bond is a mixture
of acid metal phosphates of the type of aluminium,chromium or mag-
nesium phosphate or aluminium sulphate or a mixture of metal phos-
phates and sulphates or an organosilicate compound of the type of
ethylsilicate or alkaline metasilicate.
In order to broaden the range of the synthesized thermoinsula-
ting refractory masses and their field~ of applicatlon and use,the
refractory clay and/or kaolin comprised in the refractory mass are
replaced by fine-grained refractory inactive filler of the type o~
alumlna,alumosilicate chamotte~mulite chamotte9silica,chromic oxi-
de,magnesium oxide,magnesium silicate,zirconium silicate or a mix~
ture of the same substances,taken in an amount up to 50~r
~he raw ma8s is used for insulating thermic aggregate~ by
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casting or ramming by converting it from a raw mass in a ther-
moin~ulating refractory mass under the actlon of heat emitted
by the thermic aggregate.As a result the burning out organic
substance soaked with inorganic bond that is contained in the
mass is carbonized and burns out partially without lo~ing 1~B
form thus converting in pores with microcellular ~tructureO
~ he thermoinsulating refractory mas~ can be u~ed for for-
mlng furnace walls,blocks or bricks by casting in special moulds
or casings and ~etting at a~bient temperature by means of addi-
tives accelerating the setting.In this case the burning of the
~ass can be carried out or under the action of heat of the ther-
mic aggregate or by thermic treatment in an industrial furnace.
The thermoinsulating mass can be dried up to a residual hu-
midity 5-15% and then formed by pressing while the products thus
obtained are submitted to burning in an industria~ furnace.
The ad~antages of the thermoinsulating refractory ma~3 ac-
cording to the invention are the following:a simultaneous com-
bining of high refractoriness,respectively high ~orking tempera-
ture and low thermoconductivity,possibility for varying these
parameter~ in broad ranges~use of cheap and largely available
raw-materials.All the~e favourable factors en~ure a broad and
versatile application of the refractory ma~s for insulating va-
riou~ type6 of thermic aggregates as wéll as po3~ibilitie~ for
using the mass in the form of a raw mixture and as refractory
products.
~ he ob~ect o~ the invention i9 lllustrated a~d explained in
detail by the following examples of use:
i
A mixture of following component~ i~ prepared:
refractory clay 20 weight parts
3~
kaoli~ 10 weight parts
alumina 20 weight parts
alumopho~phatlc bond 20 weight parts
water 30 weight parts
To 100 volumic parts of this mixture are added 150 volumlc
parts rice husks previously imbibed with alumophosphatlc bond,
then the mixture i9 homogenized in a mixer.The obtained plastlc
mass is applied i~ its raw form by ramming or casting on the fur-
nace roofs or by means o~' casings - on the vertical walls.Under
the action of the heat of the thermic aggregate is obtained the
thermoin~ulating refractory material with volume mas6 600 kg/m3,
thermic conducti~ity at 20C ~ 0,12 Bt/mX and maximal working
temperature - 1500C.
Examvle 2
~he same as example 1 with the only dtfference that instead
of rice husks are used wheat husks.
Example ~
The same as example 1 with the only difference that instead
of rice husks are used oats husks.
E~ample 4
~he same a~ example 1 with the only difference that instead
of rice husks are used equal parts of rice, rye and barley hu~ks.
ample 5
A mixture of following components i~ prepared:
Refractory clay . 15 weight parts
kaolln 15 weight part~
solution of sodium metasilicate
with ~olumic mass 1,7 g/cm3 30 weight parts
~ilica 20 weight parts
water 20 weight parts
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To 100 volume parts of this mixture are added 140 volu~e
parts saw-dust~,prealabl~ imblbed with aluminium sulphate.The
thus obtained plastic mas~ is u~ed in raw condition in apply-
ing it by ra~ming on the refractory brickwork of indu~trial
furnaces.The thermoinsulating mass is burned under the actlon
of heat of the furnace and ha~ ~ volume ma~s 550 kg/cm~ and
thermic conductlvity at 2CJC - 0,10 Bt/mK.
Example 6
As example 5 with the only difference that instead of saw-
dusts is used a mixture of equal parts rice husks,saw-dusts and
cellulose pulp.
Example 7
A mixture of following components is prepared:
kaolin ~0 weight parts
alumosilicate chamotte 20 weight parts
alumo-chromo-~hosphatic bond ~C weight ~arts
water 20 wei~ht parts
To 100 volume parts of this mixture are added 12~ volume
parts saw-dusts prealabl~ imbibed with alu~opho~phatic bond
and the mixture is homo~enized~Immediately before the use are
added to 95 weight parts of the mixture 5 weight parts alumi-
na cement.The new formed mixture is formed in a wood or metal
mould or in a metal casing and is allowed to set at ambient te~-
perature duri~g 1-2 twenty-four hour~he blocks obtained pO9-
ses~ a sufficient mechanical strength and are ready for use in
lining furnace wall~.The blocks are burned by thc heat of the
thermic aggregate.Thih thermoinsulating and refractory mass i~
suitable for insulating walls of stacks and other parts o~ in-
dustrlal ~urnaces.Its maximal working te-perature is 1350C.
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Exam~le 8
A mixture of following components i.~ prepared:
refractory clay 10 welght part~
silica 20 weight parte
kaolin tO welght parts
ethylsilicate 20 weight parts
water 30 welght part 9
To 100 volume parts of this mixture are added 150 ~olume
parts rice husks prealably imbibed with alumophosphatic bond~
The thus obtained plast;ic mass is applied in raw condition by
ramming on the roofs of the furnaces or by means of casings -
on the vertical walls.Under the action of heat of the thermic
aggregate is obtained the thermoinsulating refractory material
with volume mass 550 kg/m3,ther~ic conductivity at 20C-0,11
~T/m~ and maximal working temperature 1400C~
~e~
The mixture described in example 1 is dried to a residue hu-
midity 10% and then it is pressed in the form of bricks which are
submitted to drying and high-temperature burning.~he ready for
use bricks have a volume mass 600 kg~m3,compressive strength
5 MPa,coefficient of thermic conductiYity at 20C-0,12~t/mK and
they are intended for a working temperature of 1500C.
RE~ERENCES
/1/Refractorie~ and their u~eDtranslated from Japanesep
Moæoow,1984,p.2~8-304 : ; :
/2/High temperature insulation9Interceram Nr.4,1979,p.4i6-420
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