CA1070478A - Process of producing calcium aluminate trisulfate hydrate and the dehydration product thereof - Google Patents
Process of producing calcium aluminate trisulfate hydrate and the dehydration product thereofInfo
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- CA1070478A CA1070478A CA239,933A CA239933A CA1070478A CA 1070478 A CA1070478 A CA 1070478A CA 239933 A CA239933 A CA 239933A CA 1070478 A CA1070478 A CA 1070478A
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- Prior art keywords
- component
- reaction
- 3cao
- caso4
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-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/68—Aluminium compounds containing sulfur
- C01F7/74—Sulfates
- C01F7/76—Double salts, i.e. compounds containing, besides aluminium and sulfate ions, only other cations, e.g. alums
- C01F7/767—Alkaline earth metal aluminium sulfates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/06—Aluminous cements
- C04B28/065—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/32—Aluminous cements
- C04B7/323—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process of producing calcium aluminate trisulfate hydrate and the dehydration product thereof by reacting 3CaO.A?2O3.CaSO4.12H2O, 3CaO.3A?2O3.CaSO4, 3CaO.A?2O3.6H2O, or a mixture of a CaO component and an A?2O3 component with a CaSO4 component in the presence of water at temperatures below 120°C.
By the process of this invention, the aimed product having a high purity is obtained at a high yield without need of high-temperature reaction. The product of this invention is useful as building materials.
A process of producing calcium aluminate trisulfate hydrate and the dehydration product thereof by reacting 3CaO.A?2O3.CaSO4.12H2O, 3CaO.3A?2O3.CaSO4, 3CaO.A?2O3.6H2O, or a mixture of a CaO component and an A?2O3 component with a CaSO4 component in the presence of water at temperatures below 120°C.
By the process of this invention, the aimed product having a high purity is obtained at a high yield without need of high-temperature reaction. The product of this invention is useful as building materials.
Description
107V4', ~
1 R.~CKGRoUN~ OF THE INVENTION
l. Field of the Invention The present invention relates to calcium aluminate trisulfate hydrate (3CaO.A~203.3CaS04.3l-32H20) (hereinafter, the compound is referred to as TSH) and the dehydration product thereof.
1 R.~CKGRoUN~ OF THE INVENTION
l. Field of the Invention The present invention relates to calcium aluminate trisulfate hydrate (3CaO.A~203.3CaS04.3l-32H20) (hereinafter, the compound is referred to as TSH) and the dehydration product thereof.
2. Description of the Prior Art .
Hitherto, TSH has been prepared by mixing calcium oxide (CaO), aluminum oxide (AQ203), and calcium sulfate ~CaS04) at a suitable ratio and burning the mixture for 0.5 to 5 hours at 900 to 1,450C. However, the conventional process is accompanied by such faults that the process requires a large amount of energy since it requires a high-temperature burning, which makes the process uneconomical, the yield for the product is low (less than about 50%), and usually 3CaO.AQ203, 3CaO.AQ203.CaS04, CaO.AQ203, etc., are formed as by-products.
Furthermore, since in this case, the anhydrate of 3CaO.3AQ203.
CaS04 is obtained as a solid solution and thus for producing the aimed TSH, it is necessary to add necessary amounts of calcium sulfate, lime, and water to the solid solution and then subjecting the mixture to a hydration reaction (curing) for a long period of time (about 6 months) to crystallize the product.
SUMMARY OF THE INVENTION
An object of this invention is to provide a novel process of producing TSH and the dehydration product thereof suitable as building materials.
A further object of this invention is to provide a process of producing TSH and the dehydxation product thereof-having a hi~h purity at a high yield in a short reaction period ~7047~
1 of time without need of a high temperature ste?.
That is, according to the present invention, there is provided a process of producin~ TSH and the dehydration product thereof by reacting (i) 3CaO.AQ2O3.CaSO4.12H2O(MSH), (ii) 3CaO.3AQ2O3-CaSO4(C4A3S), (iii) 3CaO.AQ2O3.6H2O(C3AH6), or (iv) a mixture of a CaO component and an AQ2O3 component with a CaSO4 component in the presence of water at temperatures lower than 120C.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 - 7 are the X-ray diffraction charts of TSH.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
. . .
I. Production of TSH from MSH:
In the process of this invention, MSH may be prepared by any method. For example, MSH used in this invention as one of the raw material components ~i) is prepared by the following manners.
(1) A mixture of a CaO component, an AQ2O3 component, and a CaSO4 component at a mole ratio of 3 : 3 : 1 was burned for 0.5 to 5 hours at 1,100 to 1,500C to provide a solid solution of 3CaO.3AQ2O3.CaSO4 (or C4A3S), pulverizing the solid solution, adding further a CaO component and CaSO4 component to the reaction s~stem so that the total mole ratio of CaO, AQ2O3, and CaSO4 of the reaction system becomes almost
Hitherto, TSH has been prepared by mixing calcium oxide (CaO), aluminum oxide (AQ203), and calcium sulfate ~CaS04) at a suitable ratio and burning the mixture for 0.5 to 5 hours at 900 to 1,450C. However, the conventional process is accompanied by such faults that the process requires a large amount of energy since it requires a high-temperature burning, which makes the process uneconomical, the yield for the product is low (less than about 50%), and usually 3CaO.AQ203, 3CaO.AQ203.CaS04, CaO.AQ203, etc., are formed as by-products.
Furthermore, since in this case, the anhydrate of 3CaO.3AQ203.
CaS04 is obtained as a solid solution and thus for producing the aimed TSH, it is necessary to add necessary amounts of calcium sulfate, lime, and water to the solid solution and then subjecting the mixture to a hydration reaction (curing) for a long period of time (about 6 months) to crystallize the product.
SUMMARY OF THE INVENTION
An object of this invention is to provide a novel process of producing TSH and the dehydration product thereof suitable as building materials.
A further object of this invention is to provide a process of producing TSH and the dehydxation product thereof-having a hi~h purity at a high yield in a short reaction period ~7047~
1 of time without need of a high temperature ste?.
That is, according to the present invention, there is provided a process of producin~ TSH and the dehydration product thereof by reacting (i) 3CaO.AQ2O3.CaSO4.12H2O(MSH), (ii) 3CaO.3AQ2O3-CaSO4(C4A3S), (iii) 3CaO.AQ2O3.6H2O(C3AH6), or (iv) a mixture of a CaO component and an AQ2O3 component with a CaSO4 component in the presence of water at temperatures lower than 120C.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 - 7 are the X-ray diffraction charts of TSH.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
. . .
I. Production of TSH from MSH:
In the process of this invention, MSH may be prepared by any method. For example, MSH used in this invention as one of the raw material components ~i) is prepared by the following manners.
(1) A mixture of a CaO component, an AQ2O3 component, and a CaSO4 component at a mole ratio of 3 : 3 : 1 was burned for 0.5 to 5 hours at 1,100 to 1,500C to provide a solid solution of 3CaO.3AQ2O3.CaSO4 (or C4A3S), pulverizing the solid solution, adding further a CaO component and CaSO4 component to the reaction s~stem so that the total mole ratio of CaO, AQ2O3, and CaSO4 of the reaction system becomes almost
3 : 1 : 1, and then reacting the mixture at temperatures below 120C in the presence of a sufficient amount of water for forming water of crystallization.
In this process, examples of the CaO component are calcium oxide ~CaO), calcium hydroxide (Ca(OH~2), and a mixture of them. Also, as the AQ2O3 component, there are alumina 1070~7~
(~Q23)~ hydrated alu~ina ~23~.nH2O~ ~n is a positive integer), activated alumina, aluminum hydroxide ~Q(OH~3), and mixtures of them. Furthermore, examples of the CaSO4 component are anhydrous gypsum ~CaSO4), hemihydrate gypsum (CaSO4.1/2H2O), gypsum dihydrate (CaSO4.2H2O) and mixtures of them.
(2) A mixture of a CaO component and an AQ2O3 component at a mole ratio of about 3 : 1 was burned for about 0.5 to 5 hours at 1,100 to 1,500C to provide a solid solution of 3CaO.AQ2O3 (or C3A) as the main component, adding thereto a 1 mole of CaSO4 per 3 moles of CaO and more than 12 moles of water, and reacting the resultant mixture for about 5 to 168 hours at temperatures below 120C.
(3) A mixture of a CaO component, an AQ2O3 component, a CaSO4 component, and water at a mole ratio of 3 : 1 : 1 : at least 12 was reacted for about 1 to 8 hours at temperatures of about 100 to 200C.
The third process has been previously discovered by the inventors and since the purity of the product is high (higher than 98~), which results in requiring scarcely purifi-cation step, and thus the aforesaid process is particularlypreferable as the process of producing MSH. Furthermore, the third process is quite convenient since in the process, the same reaction apparatus as used in the step of producing TSH
by reaction MSH, CaSO4, and water can be used.
Thus, TSH is produced by adding a CaSO4 component to MSH prepared by the aforesaid processes or other processes and reacting the mixture in the presence of water at temperatures of lower than 120 ~. In this case, in case of preparing TSH
as a slurry state, a reaction promotor may be added to the reaction system as will be described below and in case of preparing 10~70478 1 shaped TSH, a filler, a rein~orcing agent, a pigment, a lubri-cant, etc., may be added to the reaction system as will also be described below.
In the embodiment of the process, there is no parti-cular limitation about the amount of calcium sulfate but it is preferred that the amount of it be about a theoretical amount or 0.7 to 1.2, more preferably 0.98 to 1.0 mole, per mole of MSH in the point of the purity and the yield for the product.
If the amount of calcium sulfate is less than 0.7 mole, MSH
remains and it affects the strength of the hardened product.
On the other hand, if the amount of calcium sulfate is more than 1.2 moles, CaSO4 remains and it affects water resistance.
Furthermore, the amount of water used in this reaction may ~e larger than 19 moles per mole of MSH, that is, may be the amount which can secure the necessary water of crystallization of TSH. If the amount of water is less than the aforesaid amount, it is neces3ary to supply the insufficient amount of water. However, this condition may be almost satisfied if there is water in an amount necessary for the shaping operation of the product.
In the process of this invention, the reaction temperature is defined to be lower than 120C since if the tem-perature is higher than 120C, the decomposition of TSH will occur. Furthermore, if the reaction temperature is in a range of 100 to 120C, the formation of TSH is comparatively slow and thus the reaction period of time required for forming TSH
becomes longer or a mixture of MSH, TSH, and gypsum is obtained.
The most preferred temperature for the reaction is 50 to 95 C
and in the temperature range the formation rate of TSH is higher.
If the reaction temperature is lower than 10C, the formation of TSH is delayed greatly.
47~
1 Thus, although the reaction period of time depends upon the reaction temperature and the desired purity of the product, it is generally from one hour to one month and, preferably, about 1 to 10 hours under ordinary preferred conditions.
The hardened product composed of MSH and TSH is superior in strength to the hardened products each composed of MSH or TSH. For preparing the hardened product of the mixture of MSH and TSH, the reaction temperature and the reaction period of time may be controlled as described above. Or a mixture may be prepared by reducing the compounding proportion of the CaS04 component.
The hardened product prepared from a mixture of 0.01 to 4 moles, preferably 0.02 to 0.7 mole, of MSH per mole of TSH
is particularly superior in strength.
In this process, the reaction system containing a large amount of MSH tends to reduce the strength of the hardened product of it while the reaction system containing a small amount of MSH tends to increase the expansibility thereof at the production of the hardened product. Thus, in the reaction system composed of MSH and TSH at a proper ratio, a hardened composition possessing a high strength is obtained by the platy crystals of the former and the acicular crystals of the latter.
II. Production of TSH from C4A3S:
C4A3S prepared by any methods may be used in this process. For example, the C4A3S prepared by the process as shown in I-(l~ is pulverized by means of a grinder such as a crusher, a sample mill, etc., and in this case the rate of the formation of TSH becomes higher as the grain size of C4A3S
107~)4~, ~
is finer. It is preferred to employ the powder of TSH of lO0 mesh (by the sieve of Taylor) under. If the powder of TSH
larger than lO0 mesh is present in the reaction system, the formation of TSH is delayed as much, which gives bad influences on the formation of the hardened product.
The powder of C4A3S thus prepared is mixed with a gypsum component and water together with, if necessary, additives such as fibrous reinforcing agent, etc., and they are reacted under a wet heat condition.
There is no limitation about the mixing ratio of the C4A3S powder and the gypsum component but it is preferred from the viewpoint of the yield and the purity of the product to use the mixing ratio of them near the theoretical amount. Thus, it is preferred that 1.5 to 2.5 moles of CaS04 be added to 1 mole of C4A3S. If the proportion of qypsum is low, a hardened product becomes inferior in strength, while if the proportion is higher than the aforesaid range, the water resistance of the hardened product tends to be lower.
Also, the amount of water employed is more than 32 moles including water of crystallization.
The reaction temperature should be lower than 120&
which is the d~composition point of TSH. However, the most preferred reaction temperature is from 50C to 95C. In the temperature range, the reaction period of time is about 3 to 8 hours.
III. Production of TSH from C3AH6:
C3AH6 used in this invention may be prepared by any processes but it can be, for example, prepared by the following process.
That is, a lime component is mixed with aluminum 1071~4~, ~
hydroxide at a ratio of 2.8 to 3.0 moles or t~e lime component and 1.6 to 2.6 moles of aluminum hydroxide. In this case, it is preferred to use a small amount of the lime component so that the unreacted lime component does not remain in the reaction product. That is, it is preferred to use less than 3 moles of the lime component per 2 moles of aluminum hydroxide. Then, more than 6 moles of water is added to the mixture to provide a reaction composition. In this case, the reaction components may be mixed in any order.
When the composition thus prepared is maintained in an autoclave or a reaction vessel at temperatures higher than 50C under a so-called wet heat condition for more than 20 minutes, C3AH6 is obtained. In addition,a suitable range of the temperature in the wet heat condition is 90 to 200C, and the upper limit is the decomposition temperature of C3AH6.
The C3AH6 prepared in the aforesaid step was ground and 1 mole of the powder of C3AH6 is mixed with 2.8 to 3.5 moles of the CaSO4 component. The mixing ratio does not mean any restriction but it is preferable to use the mixing ratio near the theoretical ratio.
The aforesaid mixture is mixed with a suitable amount of water to form a slurry or white water and by subjecting the slurry to a hydration reaction, an inorganic material of TSH
composed of 3CaO.A~2O3.3CaS04.31-32H20 is obtained. It is preferred to carry out the hydration reaction in the presence of water in an amount of more than 32 moles as total amount per mole of C3AH6 (that is, more than 26 moles per mole o~
C3A~6) at temperatures of lower than 100C, more preferably 5~ to 95C, which increases greatly the rate of reaction.
IV. Production of ~SH from a CaO component, an AQ2O3 component and a CaSO4 component:
107~)478 To a mix.ure of a CaO component, an AQ2O3 component, and a CaSO4 component at a mole ratio of 2.4 - 3.5 : 0.8 - 1 :
2.4 - 3.5, preferably 3 : l : 3 (although the mixing ratio of them is not limited to these range) is added water in an amount of larger than 32 moles per mole of AQ2O3 and a mixture is reacted for rrom one hour to one month at temperatures of usually 10 to 120C, preferably 50 to ~5C.
In the aforesaid processes of producing TSH, there are no limitations about the reaction pressures but in the reaction in which the escape of water from the reaction system must be prevented, the reaction is generally carried out at a pressure higher than the saturation vapor pressure at the reaction temperature.
According to the proce~s of this invention, a high-temperature reaction is not required and TSH having a high purity (higher than 98% under the optimum condition) can be obtained in a short period of time.
TSH prepared in this invention is useful as an expansive agent for cement as well as can be used as building materials such as ceiling materials, wall ma~erials, and flame retarding agents and further electric materials such as insulating plates by adding thereto a carbonation preventing agent, a reinforcing agent such as fibrous materials, resins, etc., and other additives such as fillers, pigments, lubri-cating agents. etc., followed by hardening.
The aforesaid additives may be added to the reaction system at any steps before the hardening of TSH. For example, the additives may be added to the mixture of the raw materials prior to the reaction and the hardening product o~ TSH can be obtained simultaneously with the production of TSH. Or, further, 107~47~
1 the additives may be added to the reaction system after the preparation of TSH and then TSH may be hardened.
The fillers are used for obtaining a caking effect, in particular, for preventing the stripping of layer of the plate hardened product and examples of the fillers are bentonite, kaolin, sericite, etc., and further calcium silicate is also used as a filler for reducing the weight of the hardened product. The amount of the filler is generally less than 35%
by weight of the total amount of the hardened product. The lubricating agent is used for enabling the release of the hardened product from a mold, etc., and as such lubricating agent, there are wax, a metal stearate such as salt of Ca, Zn, Cd and Pb, etc. They are used generally in an amount of less than 5~ by weight of the hardened product. Examples of the fibrous materials used in this invention are glass fibers, asbestos, etc., and examples of the carbonation preventing agent are fatty acids such as stearic acid, etc., and the derivatives of the fatty acids. Also, examples of the resins are polyvinyl alcohol, urea resins, etc., which are used as a binder.
Also, the dehydration product of TSH is useful for producing the hardened product thereof. The dehydrated TSH
can be produced by heating TSH to release a part or the whole of water of crystallization. It is undesirable to conduct the heating procedure under a severe condition and the tem-perature is usually lower than 900C, preferably 50 to 200C.
The treating period of time at the temperature range is from about 80 minutes to 10 hours. The product obtained by the treatment is shown by the formula 3CaO.AQ2O3.3CaSO4.nH2O (wherein n is a number of 0 to 31, preferably 10 to 20). In addition, the amount of water of crystallization is of statistical (i.e., the mean value of the number of water o' crystallization contained in the TSH dehydrates). IL n is less than 10, the dehydration tends to be reluctant to occur. If n is less than 20 (but larger than 10), the crystal of TSH once gets out of shape and the product is recrystallized by adding thereto water, which results in giving the hardened product possessing excellent strength. This tendency becomes lower as n becomes larger than 21.
Then, the product of the hardened product of TSH and 0 the dehydration product thereof will ~e explained.
The hardened product of TSH is prepared using MSH, a CaS04 component, and water. The curing temperature, that is, the reaction temperature is almost same as the condition of preparing TSH. That is, MSH, a CaS04 component, and water are mixed at a predetermined ratio and after adding, if necessary, additives such as fibrous re;nforcing agent, lubricating agent, etc., to the mixture, the resultant mixture is, with or without being shaped, cured in the presence of water necessary for the formation of wàter of crystallization of TSH. When the com-position is not shaped prior to curing, the composition ishardened in a bulk state and the hardened product is used as it is or is shaped into a desired shape.
The composition may be shaped by any desired manner.
The state of the composition to be hardened differs according to the amount of water used and thus a shaping method suitable for the state shall be selected. That is, if the amount of water is less, an extrusion molding method or a compression molding method is suitable while if the amount of water is large and the composition is in a slurry state, a pressing method or a casting method is suitable. Also, if the amount of water in a 107()47~
slurry is more larser, a paper ma.r~-acturing method (wet machine method) is suitably employed. In addition, in the case of employ-ing a casting method, it is preferred that the composition con-tains 60 to 100 parts by weight of water per 100 parts by weight of the sGlid components in the composition, while in the case of employing a paper manufacturing method, it is preferred that the composition contains 5 to 20 parts by weight of water per 1 part by weight of solid components.
If necessary, the hardened product may be dried before use. The drying step is generally carried out at 60 to 100C
(the surface temperature of the hardened product), preferably at temperatures lower than 60C. If the content of water in the hardened product is high, the product may be dried at 60 to 100C but after the water content is reduced, water of crystallization is liable to be evaporated off and hence it is desirable to dry the component at temperatures lower than 60 C.
In the case of producing TSH, in particular, the hardened product of ît from MSH, a reaction controlling agent may be used.
Among the reaction controlling agents, examples of the retarding agents used in this invention for retarding the production rate of TSH are sodium gluconate, gluconic acid, sodium citrate, citric acid, sodium hexametaphosphate, starch, carboxymethyl cellulose, gelatin, calcium oxide, and calcium hydroxide. They may be used individually or as a mixture of them. They are materials having COOH group and OH group together or are high-molecular protective colloids. They are properly added to the reaction system and there is no particular limitation about the addition amount of them but the amount is preferably 0.03 to 0.5~ by weight of the total amount of MSH
10~0478 1 and the CaS04 component. If the amount is less than 0.03% by weight, the effect o. the addition of it is not obtained, while even if the amount is over 0.5~ by weight, no further effect does increase. In the case of using calcium oxide or calcium hydroxide for the purpose, the amount is 0.5 to 5% by weight (calculated as CaO), preferably 1 to 3~ by weight.
In the case of producing the hardened product of TSH
from a mixture of, for example, MSH, a gypsum component, and water, the pot life of the mixture is ordinarily short and the mixture begins to harden after about 5 to 10 minutes. This is inconvenient for carrying out the shaping operation, molding operation, etc., of the mixture. Thus, by adding the aforesaid reaction retarding agent to the mixture, the pot life of the mixture can be prolonged conveniently. In particular, when a shearing stress is applied to the mixture by kneading, molding, etc., a mechanochemical reaction is liable to occur and in such case the addition of the reaction retarding agent is quite effective for preventîng the occurrence of the mechanochemical reaction.
Also, as the reaction accelerators for hastening the formation rate of TSH, the aromatic carboxylic acids having the following general formula or anhydrides thereof can be used.
[~ [COOH~n wherein n represents an integer from 1 to 4; R represents ~ ~ ~ or They are, for example:
107(~478 Rl-COOH such as ,~COOH
R~ OOH such as I~COOH
\COOH ~OOH
HOOC ~COQH
R3 0 such as (~ \0 20 \ \1~/ sucl~ as O ~ /
HOOC ~ COOH HOOC COOH
R~; such as ~ and HOOC COOH HOOC ~~ COOH
HOOC ~COOH
HOOC~ COOH
107047~
6 ~f / such as ~ C
COOH HOOC~ f OOH
HOOC-R such as COOH ~
COOH
wherein Rl - R7 represent ~ , ~ or ~
In particular, the aromatic carboxylic acids which are insoluble or sparingly soluble in water (solubility of less than 0.5 g/100 g-water at 20C),such as isophthalic acid, terephthalic acid, o-phthalic acid, benzoic acid, phthalic anhydride,-and the like are preferred although the reaction accelerators used in this invention are not limited to them. They may be added individually or as a mixture of 20 them.
At use, the aromatic carboxylic acid or the anhydride may be added to the reaction system of MSH, a gypsum component, and water. In this case, it is preferred that the amount of the aromatic carboxylic acid or the anhydride be 0.2 to 5.0%
by weight to the total weight of MSH and the gypsum component although the value is not intended to limit the invention in any way. Even if the amount of the aromatic carboxylic acid is over 5.0% by weight, the reaction acceleration effect does not further increase in general and if the amount is too much, the effect sometimes decreases. On the other hand, if the amount is less than 0.2~ by weight, a remarkable reaction 107~)47~
acceleration effect will no~ be obtained.
The acceleration of the reaction is necessary in the case of forming some moldings, etc., of the product and also is convenient in the case of producing TSH directly since the reaction period of time can be shortened.
In other embodiment of preparing the hardened product of TSH, a mixture of a lime component, an alumina component, and a gypsum component at a mixing ratio corresponding to the composition of TSH is, after, if necessary, adding thereto additives such as fibrous reinforcing agents, etc., cured under the same wet heat condition as in the aforesaid case of producing TSH. In this case, the mixing ratio of these raw material components are 2.4 to 3.5 moles, preferably about 3 moles, of the lime component, 2.4 to 3.5 moles, preferably about 3 moles, of the gypsum component, 0.8 to 1 mole, preferably about 1 mole, of the alumina component, and more than 32 moles of water.
In still other embodiment of producing the hardened product of TSH, TSH is first prepared and after mixing the fine powder of TSH and a definite amount of water together with, if necessary, additives such as fibrous reinforcing agent, etc., the mixture is dried under the aforesaid condition. In this case, TSH is partially dissolved in water and then it is recrystallized in the drying step to provide a hardened product.
The amount of water employed may be properly changed according to the shaping manner to be employed.
When the dehydrated TSH is hardened, the aimed pro-duct can be obtained by adding a suitable amount of water to the dehydrated TSH, shaping the mixture into a desired shape, curing the shaped mixture at temperatures of lower than 120C
for 1 to 10 hours, and drying by the aforesaid manner. The 107047~
1 proper amount of water used in this case means the amount necessary for maintaining water of crystallization (31-32H20) of TSH, preferably the amount necessary for providing a state of the mixture or convenient for shaping it. Practically speaking, although the amount of water added may depend upon the amount of the residual water of crystallization kept in the dehydrated TSH, the amount of water is more than 30 parts by weight per 100 parts of the dehydrated TSH for shaping.
In addition, additives such as fibrous reinforcing agents, fillers, polymers, pigments, etc., may be added to the mixture of the dehydrated TSH and water.
The shaping operation can be practiced by the same manner as in the aforesaid case of producing the hardened product of TSH.
The hardened product prepared by the aforesaid manner is ~uite excellent in strength and water resistance.
When the deterioration in strength of the hardened product gives no serious problem to the purpose of using the product, the hardened product may be carbonated as the case may be since in such case the specific gravity of the hardened product is reduced by carbonation. In such case TSH is hardened and the hardened product may be forcibly carbonated.
It is desirable to carry out the carbonation at temperature of 20 to 100C, preferably 40 to 80C, and a humidity of 60 to 100% R.~. If the temperature is too low, the rate of the carbonation reaction is low and if the tem-perature is too high, the shaped product is sometimes accompanied by the formation of cracks. The reaction itself becomes faster as the temperature and humidity are higher (the reaction is faster when moisture exists). In this case, it is preferable to pass carbon dioxide gas at a constant speed so that the 1(~7V4'78 1 shaped product is always brought into contact with fresh carbon dioxide gas. In addition, the same object can also be attained by allowing to stand the shaped product in the air without need of the specific carbonation step.
TSH becomes a crystalline mixture of CaCO3, A~2O3.nH2O, and CaSO4.2H2O by carbonation. The extent of car-bonation can be selected desirably according to the purpose of using the hardened product.
Then, the invention will further be explained by the following examples, in which parts and percentages are all by weight. Also, the bending strength shown in the examples is the destruction load per unit cross section when a sample of 25 mm width having an optional thickness is formed into 50 mm spun.
The temperature of water used in measuring the bending strength and the weight 109s iS 25C unless the tem-perature is not ~hown specifically.
The particle sizes of materials which are shown in mesh are measured by the sieve of Taylor (100 mesh = 149 ~ of diameter, 325 mesh = 44 ~u of diameter).
A mixture of 168 g (3 moles) of calcium oxide, 156 g (2 moles) of aluminum hydroxide, 516 g (3 moles) of gypsum dihydrate, and 1400 g (77.8 moles) of water was placed in a three liter reaction vessel and then the mixture was reacted for 24 hours at 95C ~ 2C with stirring at 60 r.p.m. while refluxing water. After the reaction was over, the reaction mixture was allowed to cool to provide a pure white product.
The X-ray diffraction analysis of the product shows the chart shown in Figure 1, which showed the formation of TSH. In the 1 figure, the peak (a) is TSH, the peak (~! is -em~aining gypsum dihydrate, and the peak (c) is a small amount of calcium hydroxide. In addition, the yield for TSH was 98.5% and the pH
of the slurry was 10.6.
After uniformly mixing 222g ~3 moles) of calcium hydroxide, 156 g ~2 moles) of aluminum hydroxide, and 506 g (4 moles) of hemihydrate gypsum by means of a ribbon mixer, 1000 g (55.5 moles) of water was further added to the mixture and the resultant mixture was further kneaded by means of a universal mixer to form a slurry. The slurry thus formed was poured in a mold of 10 mm x 100 mm x 200 mm and after 20 minutes, a coagulated semi-hardened product was obtained. When the semi-hardened product was cured for 10 days at 50C +
2C under a wet heat condition, an inorganic hardened product of TSH was obtained. The properties of the product measured are shown in the following table, which shows that the product was an inorganic hardened product having high water resistance and high strength.
Bulk specific gravity 1.1 Bending strength 46 kg/cm Wet bending strength 2 (water content 30~) 34 kg/cm Weight loss when immersed in O
running water for 24 hours at 25 C 0.37% by weight After mixing uniformly 196 g (3.5 moles) of calcium oxide, 156 g (2 moles) of aluminum hydroxide, and 602 g (3.5 moles) of gypsum dihydrate for 20 minutes by means of a ribbon .
mixer, 1300 g ~72.2 moles) of water was added to the mixture 10~()47&
and the resultant mixture w s kneaded by means of a universal mixer to form a slurry. Tne slurry was poured in a mold OI
lO mm x lO0 mm x 200 mm and after 10 minutes, the slurry coagulated to provide a semi-hardened product. When the semi-hardened product was cured for 7 days at 80C + 2C, an inorganic hardened product of TSH was obtained. The properties of the product are shown in the following table, which shows that the product was a hardened product having high water resistance and high strength.
Bulk specific gravity 0.98 Bending strength 39 kg/cm2 Wet bending strength 24 kg/cm2 (water content 35%) Weight loss when immersed in 0.8% by weight running water for 24 hours at 25C
After mixing 170 g of calcium oxide, 160 g of aluminum hydroxide, and 145 g of hemihydrate gypsum for 20 minutes by means of a ribbon mixer, 400 g of water was added to the mixture to provide a slurry. The slurry was poured in a mold of lO mm x 200 mm x 200 mm and coagulated therein to provide a shaped product. The product was subjected to a hydration reaction for 120 minutes under a wet heat condition in an autoclave of 180C. Thus, a harde~ed product mainly com-posed of MSH was obtained, which was confirmed by X-ray diffraction as shown in Figure 2 of the accompanying drawings.
In addition, the peak 1 of the chart in Figure 2 shows MSH and the peak 2 shows remaining calcium hydroxide. Also, the yield of MSH was 97%.
The MSH hardened product thus obtained was ground into a fine powder OL less than lO0 mesh and then the powder 107(J~7~
was uniformly mixed with 340 g of gy?sum dihyd-ate and 800 g of water. The slurry Cormed was subjected to a hydration reaction in a mold of 10 mm x 100 mm x 200 mm for 3 hours at 90C and at a relative humidity of 30%. Thus, a hardened product mainly composed of TSH was obtained. The X-ray diffrac-tion chart of the product is shown in Figure 3, in which the peak 3 shows TSH. The yield of TSH was 96~ ~raw material basis) and the properties of the product were as follows:
Bulk specific gravity 1~23 Bending strength 45 kg/cm Wet bending strength 34 kg/cm2 (water content 35~ weight) Weight loss after immersing in O 0.47~ by weight running water for 24 hours at 25 C
Solubility 0.806 g/100 g-H2O
Dimension increase ratio 0.3%
~water content O ~ 36% by weight) A mixture of 170 g of calcium oxide, 135 g of aluminum hydroxide, 175 g of gypsum dihydrate, and 2000 g of water was subjected to a hydration reaction for 90 minutes at 200C in a five liter high-pressure reaction vessel with stirring at a rate of 60 r.p.m. Thus, MSH was obtained at a yield of 94%. The formation of MSH was confirmed by X-ray diffraction as in Example 4.
The product (slurry) thus formed was dried in a dryer at 100 C to remove 1000 g of water. Then, 340 g of gypsum dihydrate was added to the slurry and the mixture was placed in a three liter beaker, which was allowed to stand in a desiccator at 20C and a relative humidity of 100% for a week to cause the hydration reaction. Thus, a hardened product mainly composed 107()47~3 of TSH was obtained at a yield of 93~. The formation of TSH
was also confirmed by X-ray diffraction.
A mixture of 180 g of calcium oxide, 110 g of activated alumina, 170 g of gypsum dihydrate, and 2500 g of water was placed in a five liter high-pressure reaction vessel and the hydration reaction was carried out for 180 minutes at a temperature of 140C with stirring at a rate of 80 r.p.m. to provide MSH at a yield of 96%. The formation of MSH was confirmed by X-ray diffraction.
The MSH ~slurry) thus obtained was mixed with 340 g of gypsum dihydrate and the mixture was placed in a mold followed by suction by means of an aspirator to remove 1600 g of water. The product was allowed to stand for 7 hours in a vessel of 100~ humidity at 50C and then dried at 50C for 5 hours to provide a hardened product of TSH at a yield of 95%.
The formation of TSH was confirmed by X-ray diffraction. The properties of the product were as follows:
Bulk specific gravity 0.97 ~0 2 Bending strength 31 kg/cm Wet bending strength 23 kg/cm2 ~water content 31% by weight) Weight loss when immersed in 0.61%
running water for 24 hours at 25C
Solubility 0 0O09 g/100 g H2 Dimension increase ratio 1.8 (MSH ~ TSH) EX~MPLE 7 A mixture of 16.8 g of calcium oxide, 15.6 g of aluminum hydroxide, 17.2 g of gypsum dihydrate, and 100 g of water was reacted for 3 hours at 180~ in an autoclave to provide MSH.
1070~7~
1 On the other hand, to the slur~y of MSH thus obtained was added 2 moles of gypsum dihydrate per mole of the slurry and after adding water thereto, the reaction was carried out for 12 hours at 50C while preventing the escape of water from the system to provide a slurry of TSH.
The TSH slurry was mixed with the MSH slurry at a mole ratio of 2 : 1. The mixture formed was filtered by suction, shaped into a plate, and then dried at 5~C to provide a hardened product. The properties of the product obtained are as follows:
Bulk specific gravity 0.83 Bending strength 45 kg/cm2 Weight loss when immersed in 0.42%
running water for 24 hours at 25C
In addition, by carrying out the X-ray diffraction analysis about the hardened product, the chart as shown in Figure 4 of the accompanying drawings was obtained and the product was confirmed to be a mixture of TSH and MSH. In Figure 4, T stands for TSH and M stands for MSH.
~ EXAMPLE 8 After mixing 200 g (about 3.6 moles) o calcium oxide, 170 g (about 2.2 moles) of aluminum hydroxide, and 700 g (about 8.9 moles) of water for 30 minutes by means of a universal mixer, the mixture was subjected to a hydration reaction for 120 minutes at 95C to provide a first step product. The X-ray diffraction analysis of the product showed the chart as shown in Figure 5, and the peak ta) based on C3AH6 was confirmed.
The yield of C3AH6 was 98~. Then, the product was uniformly mixed with 516 g (about 3 moles) of gypsum dihydrate with stirring to provide a uniform slurry and the slurry was maintained )478 at 90C for 50 hours while prev~nting the escape of water from the system to provide a second step final product. The X-ray diffraction analysis of the final product showed the chart as shown in Figure 6, in which the peak ~b) is the peak based on TSH shown by 3CaO.AQ2O3.3CaS04.31-32H20. Also, the formation of an inorganic material mainly composed of TSH from the first step and second step was confirmed. The yield of TSH was 96~.
After mixing 230 g ~3.1 moles) of calcium hydroxide, 170 g ~about 2.2 moles) of aluminum hydroxide, and 2000 g (111.1 moles) of water for 50 minutes by means of a universal mixer, the mixture thus formed was subjected to a hydration reaction with stirring for 60 minutes at 180C in an autoclave to provide a first step product. The X-ray diffraction analysis of the product showed a chart as in Figure 5 of Example 8 and also the peak ~a) based on C3AH6 was observed. In addition, the yield for C3AH6 was 97%.
Then, the product was mixed with 435 g (3 moles) of hemihydrate gypsum with stirring to provide a uniform slurry.
The slurry was poured in a mold of 10 mm x 100 mm x 200 mm and then allowed to stand for 10 minutes to provide a coagulated molding. The product was maintained for 7 days at 50C + 2&
while preventing the escape of water to provide a shaped second step final product. The X-ray diffraction analysis of the final product showed a chart as in Figure 6 of Examp1e 8. In addition, the yield for the TSH obtained was 97%. The properties of the shaped final product were as follows:
Bulk specific gravity 0.96 Bending strength 31 kg/cm Weight loss when immersed in 0.61~ by weight running water for 24 hours at 25C
1070~7~
EX~lPLE 10 By following the same procedure as in Example 4 usins the retarders for plaster as shown in the following table, TSH
hardened products were prepared. 0.1 wt~ of the retarders based on MSH were used. The effect of the retarders are also shown in the same table.
Retarder for Plaster Retardation Time*
.
Sodium gluconate 180 minutes Sodium citrate 110 minutes Citric acid 87 minutes Sodium hexametaphosphate 75 minutes Starch 60 minutes Carboxymethyl cellulose 56 minutes Ca(OH)2 ~2.5 wt~ calculated300 minutes as CaO was used) * The retardation time was defined to be zero when no retarder was present.
After heating 600 parts by weight of the TSH powder to 80C for 5 hours to form the dehydration product of TSH, 800 parts by weight of water was added to the dehydrate and the mixture was then poured in a mold to provide a hardened pro-duct after 30 minutes. The product was dried. The bending strength of the dry product was ~0 kg/cm2 and the specific gravity thexeof was 0.90. The X-ray diffraction analysis chart of the dehydration product of TSH is shown in Figure 7.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modi-fications can be made therein without departing from the spirit and scope thereof.
In this process, examples of the CaO component are calcium oxide ~CaO), calcium hydroxide (Ca(OH~2), and a mixture of them. Also, as the AQ2O3 component, there are alumina 1070~7~
(~Q23)~ hydrated alu~ina ~23~.nH2O~ ~n is a positive integer), activated alumina, aluminum hydroxide ~Q(OH~3), and mixtures of them. Furthermore, examples of the CaSO4 component are anhydrous gypsum ~CaSO4), hemihydrate gypsum (CaSO4.1/2H2O), gypsum dihydrate (CaSO4.2H2O) and mixtures of them.
(2) A mixture of a CaO component and an AQ2O3 component at a mole ratio of about 3 : 1 was burned for about 0.5 to 5 hours at 1,100 to 1,500C to provide a solid solution of 3CaO.AQ2O3 (or C3A) as the main component, adding thereto a 1 mole of CaSO4 per 3 moles of CaO and more than 12 moles of water, and reacting the resultant mixture for about 5 to 168 hours at temperatures below 120C.
(3) A mixture of a CaO component, an AQ2O3 component, a CaSO4 component, and water at a mole ratio of 3 : 1 : 1 : at least 12 was reacted for about 1 to 8 hours at temperatures of about 100 to 200C.
The third process has been previously discovered by the inventors and since the purity of the product is high (higher than 98~), which results in requiring scarcely purifi-cation step, and thus the aforesaid process is particularlypreferable as the process of producing MSH. Furthermore, the third process is quite convenient since in the process, the same reaction apparatus as used in the step of producing TSH
by reaction MSH, CaSO4, and water can be used.
Thus, TSH is produced by adding a CaSO4 component to MSH prepared by the aforesaid processes or other processes and reacting the mixture in the presence of water at temperatures of lower than 120 ~. In this case, in case of preparing TSH
as a slurry state, a reaction promotor may be added to the reaction system as will be described below and in case of preparing 10~70478 1 shaped TSH, a filler, a rein~orcing agent, a pigment, a lubri-cant, etc., may be added to the reaction system as will also be described below.
In the embodiment of the process, there is no parti-cular limitation about the amount of calcium sulfate but it is preferred that the amount of it be about a theoretical amount or 0.7 to 1.2, more preferably 0.98 to 1.0 mole, per mole of MSH in the point of the purity and the yield for the product.
If the amount of calcium sulfate is less than 0.7 mole, MSH
remains and it affects the strength of the hardened product.
On the other hand, if the amount of calcium sulfate is more than 1.2 moles, CaSO4 remains and it affects water resistance.
Furthermore, the amount of water used in this reaction may ~e larger than 19 moles per mole of MSH, that is, may be the amount which can secure the necessary water of crystallization of TSH. If the amount of water is less than the aforesaid amount, it is neces3ary to supply the insufficient amount of water. However, this condition may be almost satisfied if there is water in an amount necessary for the shaping operation of the product.
In the process of this invention, the reaction temperature is defined to be lower than 120C since if the tem-perature is higher than 120C, the decomposition of TSH will occur. Furthermore, if the reaction temperature is in a range of 100 to 120C, the formation of TSH is comparatively slow and thus the reaction period of time required for forming TSH
becomes longer or a mixture of MSH, TSH, and gypsum is obtained.
The most preferred temperature for the reaction is 50 to 95 C
and in the temperature range the formation rate of TSH is higher.
If the reaction temperature is lower than 10C, the formation of TSH is delayed greatly.
47~
1 Thus, although the reaction period of time depends upon the reaction temperature and the desired purity of the product, it is generally from one hour to one month and, preferably, about 1 to 10 hours under ordinary preferred conditions.
The hardened product composed of MSH and TSH is superior in strength to the hardened products each composed of MSH or TSH. For preparing the hardened product of the mixture of MSH and TSH, the reaction temperature and the reaction period of time may be controlled as described above. Or a mixture may be prepared by reducing the compounding proportion of the CaS04 component.
The hardened product prepared from a mixture of 0.01 to 4 moles, preferably 0.02 to 0.7 mole, of MSH per mole of TSH
is particularly superior in strength.
In this process, the reaction system containing a large amount of MSH tends to reduce the strength of the hardened product of it while the reaction system containing a small amount of MSH tends to increase the expansibility thereof at the production of the hardened product. Thus, in the reaction system composed of MSH and TSH at a proper ratio, a hardened composition possessing a high strength is obtained by the platy crystals of the former and the acicular crystals of the latter.
II. Production of TSH from C4A3S:
C4A3S prepared by any methods may be used in this process. For example, the C4A3S prepared by the process as shown in I-(l~ is pulverized by means of a grinder such as a crusher, a sample mill, etc., and in this case the rate of the formation of TSH becomes higher as the grain size of C4A3S
107~)4~, ~
is finer. It is preferred to employ the powder of TSH of lO0 mesh (by the sieve of Taylor) under. If the powder of TSH
larger than lO0 mesh is present in the reaction system, the formation of TSH is delayed as much, which gives bad influences on the formation of the hardened product.
The powder of C4A3S thus prepared is mixed with a gypsum component and water together with, if necessary, additives such as fibrous reinforcing agent, etc., and they are reacted under a wet heat condition.
There is no limitation about the mixing ratio of the C4A3S powder and the gypsum component but it is preferred from the viewpoint of the yield and the purity of the product to use the mixing ratio of them near the theoretical amount. Thus, it is preferred that 1.5 to 2.5 moles of CaS04 be added to 1 mole of C4A3S. If the proportion of qypsum is low, a hardened product becomes inferior in strength, while if the proportion is higher than the aforesaid range, the water resistance of the hardened product tends to be lower.
Also, the amount of water employed is more than 32 moles including water of crystallization.
The reaction temperature should be lower than 120&
which is the d~composition point of TSH. However, the most preferred reaction temperature is from 50C to 95C. In the temperature range, the reaction period of time is about 3 to 8 hours.
III. Production of TSH from C3AH6:
C3AH6 used in this invention may be prepared by any processes but it can be, for example, prepared by the following process.
That is, a lime component is mixed with aluminum 1071~4~, ~
hydroxide at a ratio of 2.8 to 3.0 moles or t~e lime component and 1.6 to 2.6 moles of aluminum hydroxide. In this case, it is preferred to use a small amount of the lime component so that the unreacted lime component does not remain in the reaction product. That is, it is preferred to use less than 3 moles of the lime component per 2 moles of aluminum hydroxide. Then, more than 6 moles of water is added to the mixture to provide a reaction composition. In this case, the reaction components may be mixed in any order.
When the composition thus prepared is maintained in an autoclave or a reaction vessel at temperatures higher than 50C under a so-called wet heat condition for more than 20 minutes, C3AH6 is obtained. In addition,a suitable range of the temperature in the wet heat condition is 90 to 200C, and the upper limit is the decomposition temperature of C3AH6.
The C3AH6 prepared in the aforesaid step was ground and 1 mole of the powder of C3AH6 is mixed with 2.8 to 3.5 moles of the CaSO4 component. The mixing ratio does not mean any restriction but it is preferable to use the mixing ratio near the theoretical ratio.
The aforesaid mixture is mixed with a suitable amount of water to form a slurry or white water and by subjecting the slurry to a hydration reaction, an inorganic material of TSH
composed of 3CaO.A~2O3.3CaS04.31-32H20 is obtained. It is preferred to carry out the hydration reaction in the presence of water in an amount of more than 32 moles as total amount per mole of C3AH6 (that is, more than 26 moles per mole o~
C3A~6) at temperatures of lower than 100C, more preferably 5~ to 95C, which increases greatly the rate of reaction.
IV. Production of ~SH from a CaO component, an AQ2O3 component and a CaSO4 component:
107~)478 To a mix.ure of a CaO component, an AQ2O3 component, and a CaSO4 component at a mole ratio of 2.4 - 3.5 : 0.8 - 1 :
2.4 - 3.5, preferably 3 : l : 3 (although the mixing ratio of them is not limited to these range) is added water in an amount of larger than 32 moles per mole of AQ2O3 and a mixture is reacted for rrom one hour to one month at temperatures of usually 10 to 120C, preferably 50 to ~5C.
In the aforesaid processes of producing TSH, there are no limitations about the reaction pressures but in the reaction in which the escape of water from the reaction system must be prevented, the reaction is generally carried out at a pressure higher than the saturation vapor pressure at the reaction temperature.
According to the proce~s of this invention, a high-temperature reaction is not required and TSH having a high purity (higher than 98% under the optimum condition) can be obtained in a short period of time.
TSH prepared in this invention is useful as an expansive agent for cement as well as can be used as building materials such as ceiling materials, wall ma~erials, and flame retarding agents and further electric materials such as insulating plates by adding thereto a carbonation preventing agent, a reinforcing agent such as fibrous materials, resins, etc., and other additives such as fillers, pigments, lubri-cating agents. etc., followed by hardening.
The aforesaid additives may be added to the reaction system at any steps before the hardening of TSH. For example, the additives may be added to the mixture of the raw materials prior to the reaction and the hardening product o~ TSH can be obtained simultaneously with the production of TSH. Or, further, 107~47~
1 the additives may be added to the reaction system after the preparation of TSH and then TSH may be hardened.
The fillers are used for obtaining a caking effect, in particular, for preventing the stripping of layer of the plate hardened product and examples of the fillers are bentonite, kaolin, sericite, etc., and further calcium silicate is also used as a filler for reducing the weight of the hardened product. The amount of the filler is generally less than 35%
by weight of the total amount of the hardened product. The lubricating agent is used for enabling the release of the hardened product from a mold, etc., and as such lubricating agent, there are wax, a metal stearate such as salt of Ca, Zn, Cd and Pb, etc. They are used generally in an amount of less than 5~ by weight of the hardened product. Examples of the fibrous materials used in this invention are glass fibers, asbestos, etc., and examples of the carbonation preventing agent are fatty acids such as stearic acid, etc., and the derivatives of the fatty acids. Also, examples of the resins are polyvinyl alcohol, urea resins, etc., which are used as a binder.
Also, the dehydration product of TSH is useful for producing the hardened product thereof. The dehydrated TSH
can be produced by heating TSH to release a part or the whole of water of crystallization. It is undesirable to conduct the heating procedure under a severe condition and the tem-perature is usually lower than 900C, preferably 50 to 200C.
The treating period of time at the temperature range is from about 80 minutes to 10 hours. The product obtained by the treatment is shown by the formula 3CaO.AQ2O3.3CaSO4.nH2O (wherein n is a number of 0 to 31, preferably 10 to 20). In addition, the amount of water of crystallization is of statistical (i.e., the mean value of the number of water o' crystallization contained in the TSH dehydrates). IL n is less than 10, the dehydration tends to be reluctant to occur. If n is less than 20 (but larger than 10), the crystal of TSH once gets out of shape and the product is recrystallized by adding thereto water, which results in giving the hardened product possessing excellent strength. This tendency becomes lower as n becomes larger than 21.
Then, the product of the hardened product of TSH and 0 the dehydration product thereof will ~e explained.
The hardened product of TSH is prepared using MSH, a CaS04 component, and water. The curing temperature, that is, the reaction temperature is almost same as the condition of preparing TSH. That is, MSH, a CaS04 component, and water are mixed at a predetermined ratio and after adding, if necessary, additives such as fibrous re;nforcing agent, lubricating agent, etc., to the mixture, the resultant mixture is, with or without being shaped, cured in the presence of water necessary for the formation of wàter of crystallization of TSH. When the com-position is not shaped prior to curing, the composition ishardened in a bulk state and the hardened product is used as it is or is shaped into a desired shape.
The composition may be shaped by any desired manner.
The state of the composition to be hardened differs according to the amount of water used and thus a shaping method suitable for the state shall be selected. That is, if the amount of water is less, an extrusion molding method or a compression molding method is suitable while if the amount of water is large and the composition is in a slurry state, a pressing method or a casting method is suitable. Also, if the amount of water in a 107()47~
slurry is more larser, a paper ma.r~-acturing method (wet machine method) is suitably employed. In addition, in the case of employ-ing a casting method, it is preferred that the composition con-tains 60 to 100 parts by weight of water per 100 parts by weight of the sGlid components in the composition, while in the case of employing a paper manufacturing method, it is preferred that the composition contains 5 to 20 parts by weight of water per 1 part by weight of solid components.
If necessary, the hardened product may be dried before use. The drying step is generally carried out at 60 to 100C
(the surface temperature of the hardened product), preferably at temperatures lower than 60C. If the content of water in the hardened product is high, the product may be dried at 60 to 100C but after the water content is reduced, water of crystallization is liable to be evaporated off and hence it is desirable to dry the component at temperatures lower than 60 C.
In the case of producing TSH, in particular, the hardened product of ît from MSH, a reaction controlling agent may be used.
Among the reaction controlling agents, examples of the retarding agents used in this invention for retarding the production rate of TSH are sodium gluconate, gluconic acid, sodium citrate, citric acid, sodium hexametaphosphate, starch, carboxymethyl cellulose, gelatin, calcium oxide, and calcium hydroxide. They may be used individually or as a mixture of them. They are materials having COOH group and OH group together or are high-molecular protective colloids. They are properly added to the reaction system and there is no particular limitation about the addition amount of them but the amount is preferably 0.03 to 0.5~ by weight of the total amount of MSH
10~0478 1 and the CaS04 component. If the amount is less than 0.03% by weight, the effect o. the addition of it is not obtained, while even if the amount is over 0.5~ by weight, no further effect does increase. In the case of using calcium oxide or calcium hydroxide for the purpose, the amount is 0.5 to 5% by weight (calculated as CaO), preferably 1 to 3~ by weight.
In the case of producing the hardened product of TSH
from a mixture of, for example, MSH, a gypsum component, and water, the pot life of the mixture is ordinarily short and the mixture begins to harden after about 5 to 10 minutes. This is inconvenient for carrying out the shaping operation, molding operation, etc., of the mixture. Thus, by adding the aforesaid reaction retarding agent to the mixture, the pot life of the mixture can be prolonged conveniently. In particular, when a shearing stress is applied to the mixture by kneading, molding, etc., a mechanochemical reaction is liable to occur and in such case the addition of the reaction retarding agent is quite effective for preventîng the occurrence of the mechanochemical reaction.
Also, as the reaction accelerators for hastening the formation rate of TSH, the aromatic carboxylic acids having the following general formula or anhydrides thereof can be used.
[~ [COOH~n wherein n represents an integer from 1 to 4; R represents ~ ~ ~ or They are, for example:
107(~478 Rl-COOH such as ,~COOH
R~ OOH such as I~COOH
\COOH ~OOH
HOOC ~COQH
R3 0 such as (~ \0 20 \ \1~/ sucl~ as O ~ /
HOOC ~ COOH HOOC COOH
R~; such as ~ and HOOC COOH HOOC ~~ COOH
HOOC ~COOH
HOOC~ COOH
107047~
6 ~f / such as ~ C
COOH HOOC~ f OOH
HOOC-R such as COOH ~
COOH
wherein Rl - R7 represent ~ , ~ or ~
In particular, the aromatic carboxylic acids which are insoluble or sparingly soluble in water (solubility of less than 0.5 g/100 g-water at 20C),such as isophthalic acid, terephthalic acid, o-phthalic acid, benzoic acid, phthalic anhydride,-and the like are preferred although the reaction accelerators used in this invention are not limited to them. They may be added individually or as a mixture of 20 them.
At use, the aromatic carboxylic acid or the anhydride may be added to the reaction system of MSH, a gypsum component, and water. In this case, it is preferred that the amount of the aromatic carboxylic acid or the anhydride be 0.2 to 5.0%
by weight to the total weight of MSH and the gypsum component although the value is not intended to limit the invention in any way. Even if the amount of the aromatic carboxylic acid is over 5.0% by weight, the reaction acceleration effect does not further increase in general and if the amount is too much, the effect sometimes decreases. On the other hand, if the amount is less than 0.2~ by weight, a remarkable reaction 107~)47~
acceleration effect will no~ be obtained.
The acceleration of the reaction is necessary in the case of forming some moldings, etc., of the product and also is convenient in the case of producing TSH directly since the reaction period of time can be shortened.
In other embodiment of preparing the hardened product of TSH, a mixture of a lime component, an alumina component, and a gypsum component at a mixing ratio corresponding to the composition of TSH is, after, if necessary, adding thereto additives such as fibrous reinforcing agents, etc., cured under the same wet heat condition as in the aforesaid case of producing TSH. In this case, the mixing ratio of these raw material components are 2.4 to 3.5 moles, preferably about 3 moles, of the lime component, 2.4 to 3.5 moles, preferably about 3 moles, of the gypsum component, 0.8 to 1 mole, preferably about 1 mole, of the alumina component, and more than 32 moles of water.
In still other embodiment of producing the hardened product of TSH, TSH is first prepared and after mixing the fine powder of TSH and a definite amount of water together with, if necessary, additives such as fibrous reinforcing agent, etc., the mixture is dried under the aforesaid condition. In this case, TSH is partially dissolved in water and then it is recrystallized in the drying step to provide a hardened product.
The amount of water employed may be properly changed according to the shaping manner to be employed.
When the dehydrated TSH is hardened, the aimed pro-duct can be obtained by adding a suitable amount of water to the dehydrated TSH, shaping the mixture into a desired shape, curing the shaped mixture at temperatures of lower than 120C
for 1 to 10 hours, and drying by the aforesaid manner. The 107047~
1 proper amount of water used in this case means the amount necessary for maintaining water of crystallization (31-32H20) of TSH, preferably the amount necessary for providing a state of the mixture or convenient for shaping it. Practically speaking, although the amount of water added may depend upon the amount of the residual water of crystallization kept in the dehydrated TSH, the amount of water is more than 30 parts by weight per 100 parts of the dehydrated TSH for shaping.
In addition, additives such as fibrous reinforcing agents, fillers, polymers, pigments, etc., may be added to the mixture of the dehydrated TSH and water.
The shaping operation can be practiced by the same manner as in the aforesaid case of producing the hardened product of TSH.
The hardened product prepared by the aforesaid manner is ~uite excellent in strength and water resistance.
When the deterioration in strength of the hardened product gives no serious problem to the purpose of using the product, the hardened product may be carbonated as the case may be since in such case the specific gravity of the hardened product is reduced by carbonation. In such case TSH is hardened and the hardened product may be forcibly carbonated.
It is desirable to carry out the carbonation at temperature of 20 to 100C, preferably 40 to 80C, and a humidity of 60 to 100% R.~. If the temperature is too low, the rate of the carbonation reaction is low and if the tem-perature is too high, the shaped product is sometimes accompanied by the formation of cracks. The reaction itself becomes faster as the temperature and humidity are higher (the reaction is faster when moisture exists). In this case, it is preferable to pass carbon dioxide gas at a constant speed so that the 1(~7V4'78 1 shaped product is always brought into contact with fresh carbon dioxide gas. In addition, the same object can also be attained by allowing to stand the shaped product in the air without need of the specific carbonation step.
TSH becomes a crystalline mixture of CaCO3, A~2O3.nH2O, and CaSO4.2H2O by carbonation. The extent of car-bonation can be selected desirably according to the purpose of using the hardened product.
Then, the invention will further be explained by the following examples, in which parts and percentages are all by weight. Also, the bending strength shown in the examples is the destruction load per unit cross section when a sample of 25 mm width having an optional thickness is formed into 50 mm spun.
The temperature of water used in measuring the bending strength and the weight 109s iS 25C unless the tem-perature is not ~hown specifically.
The particle sizes of materials which are shown in mesh are measured by the sieve of Taylor (100 mesh = 149 ~ of diameter, 325 mesh = 44 ~u of diameter).
A mixture of 168 g (3 moles) of calcium oxide, 156 g (2 moles) of aluminum hydroxide, 516 g (3 moles) of gypsum dihydrate, and 1400 g (77.8 moles) of water was placed in a three liter reaction vessel and then the mixture was reacted for 24 hours at 95C ~ 2C with stirring at 60 r.p.m. while refluxing water. After the reaction was over, the reaction mixture was allowed to cool to provide a pure white product.
The X-ray diffraction analysis of the product shows the chart shown in Figure 1, which showed the formation of TSH. In the 1 figure, the peak (a) is TSH, the peak (~! is -em~aining gypsum dihydrate, and the peak (c) is a small amount of calcium hydroxide. In addition, the yield for TSH was 98.5% and the pH
of the slurry was 10.6.
After uniformly mixing 222g ~3 moles) of calcium hydroxide, 156 g ~2 moles) of aluminum hydroxide, and 506 g (4 moles) of hemihydrate gypsum by means of a ribbon mixer, 1000 g (55.5 moles) of water was further added to the mixture and the resultant mixture was further kneaded by means of a universal mixer to form a slurry. The slurry thus formed was poured in a mold of 10 mm x 100 mm x 200 mm and after 20 minutes, a coagulated semi-hardened product was obtained. When the semi-hardened product was cured for 10 days at 50C +
2C under a wet heat condition, an inorganic hardened product of TSH was obtained. The properties of the product measured are shown in the following table, which shows that the product was an inorganic hardened product having high water resistance and high strength.
Bulk specific gravity 1.1 Bending strength 46 kg/cm Wet bending strength 2 (water content 30~) 34 kg/cm Weight loss when immersed in O
running water for 24 hours at 25 C 0.37% by weight After mixing uniformly 196 g (3.5 moles) of calcium oxide, 156 g (2 moles) of aluminum hydroxide, and 602 g (3.5 moles) of gypsum dihydrate for 20 minutes by means of a ribbon .
mixer, 1300 g ~72.2 moles) of water was added to the mixture 10~()47&
and the resultant mixture w s kneaded by means of a universal mixer to form a slurry. Tne slurry was poured in a mold OI
lO mm x lO0 mm x 200 mm and after 10 minutes, the slurry coagulated to provide a semi-hardened product. When the semi-hardened product was cured for 7 days at 80C + 2C, an inorganic hardened product of TSH was obtained. The properties of the product are shown in the following table, which shows that the product was a hardened product having high water resistance and high strength.
Bulk specific gravity 0.98 Bending strength 39 kg/cm2 Wet bending strength 24 kg/cm2 (water content 35%) Weight loss when immersed in 0.8% by weight running water for 24 hours at 25C
After mixing 170 g of calcium oxide, 160 g of aluminum hydroxide, and 145 g of hemihydrate gypsum for 20 minutes by means of a ribbon mixer, 400 g of water was added to the mixture to provide a slurry. The slurry was poured in a mold of lO mm x 200 mm x 200 mm and coagulated therein to provide a shaped product. The product was subjected to a hydration reaction for 120 minutes under a wet heat condition in an autoclave of 180C. Thus, a harde~ed product mainly com-posed of MSH was obtained, which was confirmed by X-ray diffraction as shown in Figure 2 of the accompanying drawings.
In addition, the peak 1 of the chart in Figure 2 shows MSH and the peak 2 shows remaining calcium hydroxide. Also, the yield of MSH was 97%.
The MSH hardened product thus obtained was ground into a fine powder OL less than lO0 mesh and then the powder 107(J~7~
was uniformly mixed with 340 g of gy?sum dihyd-ate and 800 g of water. The slurry Cormed was subjected to a hydration reaction in a mold of 10 mm x 100 mm x 200 mm for 3 hours at 90C and at a relative humidity of 30%. Thus, a hardened product mainly composed of TSH was obtained. The X-ray diffrac-tion chart of the product is shown in Figure 3, in which the peak 3 shows TSH. The yield of TSH was 96~ ~raw material basis) and the properties of the product were as follows:
Bulk specific gravity 1~23 Bending strength 45 kg/cm Wet bending strength 34 kg/cm2 (water content 35~ weight) Weight loss after immersing in O 0.47~ by weight running water for 24 hours at 25 C
Solubility 0.806 g/100 g-H2O
Dimension increase ratio 0.3%
~water content O ~ 36% by weight) A mixture of 170 g of calcium oxide, 135 g of aluminum hydroxide, 175 g of gypsum dihydrate, and 2000 g of water was subjected to a hydration reaction for 90 minutes at 200C in a five liter high-pressure reaction vessel with stirring at a rate of 60 r.p.m. Thus, MSH was obtained at a yield of 94%. The formation of MSH was confirmed by X-ray diffraction as in Example 4.
The product (slurry) thus formed was dried in a dryer at 100 C to remove 1000 g of water. Then, 340 g of gypsum dihydrate was added to the slurry and the mixture was placed in a three liter beaker, which was allowed to stand in a desiccator at 20C and a relative humidity of 100% for a week to cause the hydration reaction. Thus, a hardened product mainly composed 107()47~3 of TSH was obtained at a yield of 93~. The formation of TSH
was also confirmed by X-ray diffraction.
A mixture of 180 g of calcium oxide, 110 g of activated alumina, 170 g of gypsum dihydrate, and 2500 g of water was placed in a five liter high-pressure reaction vessel and the hydration reaction was carried out for 180 minutes at a temperature of 140C with stirring at a rate of 80 r.p.m. to provide MSH at a yield of 96%. The formation of MSH was confirmed by X-ray diffraction.
The MSH ~slurry) thus obtained was mixed with 340 g of gypsum dihydrate and the mixture was placed in a mold followed by suction by means of an aspirator to remove 1600 g of water. The product was allowed to stand for 7 hours in a vessel of 100~ humidity at 50C and then dried at 50C for 5 hours to provide a hardened product of TSH at a yield of 95%.
The formation of TSH was confirmed by X-ray diffraction. The properties of the product were as follows:
Bulk specific gravity 0.97 ~0 2 Bending strength 31 kg/cm Wet bending strength 23 kg/cm2 ~water content 31% by weight) Weight loss when immersed in 0.61%
running water for 24 hours at 25C
Solubility 0 0O09 g/100 g H2 Dimension increase ratio 1.8 (MSH ~ TSH) EX~MPLE 7 A mixture of 16.8 g of calcium oxide, 15.6 g of aluminum hydroxide, 17.2 g of gypsum dihydrate, and 100 g of water was reacted for 3 hours at 180~ in an autoclave to provide MSH.
1070~7~
1 On the other hand, to the slur~y of MSH thus obtained was added 2 moles of gypsum dihydrate per mole of the slurry and after adding water thereto, the reaction was carried out for 12 hours at 50C while preventing the escape of water from the system to provide a slurry of TSH.
The TSH slurry was mixed with the MSH slurry at a mole ratio of 2 : 1. The mixture formed was filtered by suction, shaped into a plate, and then dried at 5~C to provide a hardened product. The properties of the product obtained are as follows:
Bulk specific gravity 0.83 Bending strength 45 kg/cm2 Weight loss when immersed in 0.42%
running water for 24 hours at 25C
In addition, by carrying out the X-ray diffraction analysis about the hardened product, the chart as shown in Figure 4 of the accompanying drawings was obtained and the product was confirmed to be a mixture of TSH and MSH. In Figure 4, T stands for TSH and M stands for MSH.
~ EXAMPLE 8 After mixing 200 g (about 3.6 moles) o calcium oxide, 170 g (about 2.2 moles) of aluminum hydroxide, and 700 g (about 8.9 moles) of water for 30 minutes by means of a universal mixer, the mixture was subjected to a hydration reaction for 120 minutes at 95C to provide a first step product. The X-ray diffraction analysis of the product showed the chart as shown in Figure 5, and the peak ta) based on C3AH6 was confirmed.
The yield of C3AH6 was 98~. Then, the product was uniformly mixed with 516 g (about 3 moles) of gypsum dihydrate with stirring to provide a uniform slurry and the slurry was maintained )478 at 90C for 50 hours while prev~nting the escape of water from the system to provide a second step final product. The X-ray diffraction analysis of the final product showed the chart as shown in Figure 6, in which the peak ~b) is the peak based on TSH shown by 3CaO.AQ2O3.3CaS04.31-32H20. Also, the formation of an inorganic material mainly composed of TSH from the first step and second step was confirmed. The yield of TSH was 96~.
After mixing 230 g ~3.1 moles) of calcium hydroxide, 170 g ~about 2.2 moles) of aluminum hydroxide, and 2000 g (111.1 moles) of water for 50 minutes by means of a universal mixer, the mixture thus formed was subjected to a hydration reaction with stirring for 60 minutes at 180C in an autoclave to provide a first step product. The X-ray diffraction analysis of the product showed a chart as in Figure 5 of Example 8 and also the peak ~a) based on C3AH6 was observed. In addition, the yield for C3AH6 was 97%.
Then, the product was mixed with 435 g (3 moles) of hemihydrate gypsum with stirring to provide a uniform slurry.
The slurry was poured in a mold of 10 mm x 100 mm x 200 mm and then allowed to stand for 10 minutes to provide a coagulated molding. The product was maintained for 7 days at 50C + 2&
while preventing the escape of water to provide a shaped second step final product. The X-ray diffraction analysis of the final product showed a chart as in Figure 6 of Examp1e 8. In addition, the yield for the TSH obtained was 97%. The properties of the shaped final product were as follows:
Bulk specific gravity 0.96 Bending strength 31 kg/cm Weight loss when immersed in 0.61~ by weight running water for 24 hours at 25C
1070~7~
EX~lPLE 10 By following the same procedure as in Example 4 usins the retarders for plaster as shown in the following table, TSH
hardened products were prepared. 0.1 wt~ of the retarders based on MSH were used. The effect of the retarders are also shown in the same table.
Retarder for Plaster Retardation Time*
.
Sodium gluconate 180 minutes Sodium citrate 110 minutes Citric acid 87 minutes Sodium hexametaphosphate 75 minutes Starch 60 minutes Carboxymethyl cellulose 56 minutes Ca(OH)2 ~2.5 wt~ calculated300 minutes as CaO was used) * The retardation time was defined to be zero when no retarder was present.
After heating 600 parts by weight of the TSH powder to 80C for 5 hours to form the dehydration product of TSH, 800 parts by weight of water was added to the dehydrate and the mixture was then poured in a mold to provide a hardened pro-duct after 30 minutes. The product was dried. The bending strength of the dry product was ~0 kg/cm2 and the specific gravity thexeof was 0.90. The X-ray diffraction analysis chart of the dehydration product of TSH is shown in Figure 7.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modi-fications can be made therein without departing from the spirit and scope thereof.
Claims (30)
1. A process of producing calcium aluminate trisulfate hydrate (3CaO.A?2O3.3CaSO4.31-32H2O) which comprises reacting a raw material selected from the group consisting of (i) 3CaO.
A?2O3.CaSO4.12H2O, (ii) 3CaO.3A?2O3.CaSO4, (iii) 3CaO.A?2O3.
6H2O, and (iv) a mixture of a CaO component and an A?2O3 component with a CaSO4 component in the presence of water at temperatures of lower than 120°C.
A?2O3.CaSO4.12H2O, (ii) 3CaO.3A?2O3.CaSO4, (iii) 3CaO.A?2O3.
6H2O, and (iv) a mixture of a CaO component and an A?2O3 component with a CaSO4 component in the presence of water at temperatures of lower than 120°C.
2. The process as claimed in claim 1 wherein said CaO
component is at least one component selected from the group consisting of calcium oxide and calcium hydroxide.
component is at least one component selected from the group consisting of calcium oxide and calcium hydroxide.
3. The process as claimed in claim 1 wherein said A?2O3 component is at least one component selected from the group consisting of alumina, hydrated alumina, activated alumina, and aluminum hydroxide.
4. The process as claimed in claim 1 wherein said CaSO4 component is at least one component selected from the group consisting of anhydrous gypsum, hemihydrate gypsum, and gypsum dihydrate.
5. The process as claimed in claim 1 wherein said reaction is carried out at temperatures of 95 to 50°C.
6. The process as claimed in claim 1 wherein the theoretical proportions of the CaSO4 component and water in the reaction system are 2.0 moles and more than 19 moles, respectively, per mole of 3CaO.A?2O3?CaSO4?12H2O.
7. The process as claimed in claim 1 wherein said 3CaO.A?2O3.CaSO4.12H2O is prepared by reacting a CaO component, an A?2O3 component, a CaSO4 component, and water at temperatures of 100 to 200°C.
8. The process as claimed in claim 1 wherein the theoretical proportions of the CaSO4 component and water in the reaction system are 2.0 to 2.5 moles and more than 32 moles, respectively, per mole of 3CaO.3A?2O3.CaSO4.
9. The process as claimed in claim 8 wherein the reaction temperature is 50 to 95°C.
10. The process as claimed in claim 1 wherein the theoretical proportions of the CaSO4 component and water in the reaction system are 3.0 to 3.5 moles and more than 26 moles, respectively, per mole of 3CaO.A?2O3.6H2O.
11. The process as claimed in claim 10 wherein the reaction temperature is 50 to 95°C.
12. The process as claimed in claim 1 wherein the mole ratio of the CaO component, the A?2O3 component, the CaSO4 component, and water is 3.0 to 3.5 : 1 (calculated as A?2O3) :
3.0 to 3.5 : > 32.
3.0 to 3.5 : > 32.
13. The process as claimed in claim 12 wherein the reaction temperature is 50 to 95°C.
14. The process as claimed in claim 1 wherein the reaction is carried out in the presence of at least one additive.
15. The process as claimed in claim 1 wherein the 3CaO.A?2O3.3CaSO4.31-32H2O produced is further dehydrated by heating.
15. The process as claimed in claim 1 wherein the 3CaO.A?2O3.3CaSO4.31-32H2O produced is further dehydrated by heating.
Claim 15 continued:
to provide 3CaO.A?2O3.3CaSO4.nH2O, wherein n is a number of 0 to 31.
to provide 3CaO.A?2O3.3CaSO4.nH2O, wherein n is a number of 0 to 31.
16. The process as claimed in claim 15 wherein the heating temperature is lower than 900°C.
17. The process as claimed in claim 16 wherein the heating temperature is 50 to 200°C.
18. The process as claimed in claim 15 wherein n is 10 to 20.
19. The process as claimed in claim 1 wherein the reaction is carried out in the presence of at least one additive selected from the group consisting of a filler, a pigment, and a lubricating agent.
20. The process as claimed in claim 7 wherein the reaction is carried out in the presence of at least one additive selected from the group consisting of a filler, a pigment, and a lubricating agent.
21. The process as claimed in claim 7 wherein the reaction is carried out at 100 to 120°C and the reaction product contains 3CaO.A?2O3.CaSO4.12H2O.
22. The process as claimed in claim 1 wherein the reaction of 3CaO.A?2O3.CaSO4.12H2O, the CaSO4 component, and water is carried out using a compound having-COOH group and-OH group in the molecule or a high molecular weight protective colloid as a reaction retarding agent.
23. The process as claimed in claim 22 wherein said reaction retarding agent is at least one member selected from the group consisting of sodium gluconate, gluconic acid, sodium citrate,
23. The process as claimed in claim 22 wherein said reaction retarding agent is at least one member selected from the group consisting of sodium gluconate, gluconic acid, sodium citrate,
Claim 23 continued ......
citric acid, sodium hexametaphosphate, starch, carboxymethyl cellulose, and gelatin.
citric acid, sodium hexametaphosphate, starch, carboxymethyl cellulose, and gelatin.
24. The process as claimed in claim 23 wherein the pro-portion of said reaction retarding agent is 0.03 to 0.5% by weight to the total amount of 3CaO.A?Q2O3.CaSO4.12H2O and the CaSO4 component.
25. The process as claimed in claim 1 wherein the reaction of 3CaO.A?2O3.CaSO4.12H2O, the CaSO4 component, and water is carried out in the presence of at least one reaction retard-ing agent selected from the group consisting of calcium oxide and calcium hydroxide.
26. The process as claimed in claim 25 wherein the pro-portion of said reaction retarding agent is 0.5 to 5% by weight of the total amount of 3CaO.A?2O3.CaSO4.12H2O and the CaSO4 component.
27. The process as claimed in claim 1 wherein the reaction of 3CaO.A?2O3.CaSO4.12H2O, the CaSO4 component, and water is carried out in the presence of an aromatic carboxylic acid re-presented by the general formula:
or its anhydride, wherein n represents an integer from 1 to 4;
R represents , or .
or its anhydride, wherein n represents an integer from 1 to 4;
R represents , or .
28. The process as claimed in claim 27 wherein said aromatic carboxylic acid is at least one compound selected from the group consisting of isophthalic acid, terephthalic acid, o-phthalic acid, benzoic acid, and phthalic anhydride.
29. The process as claimed in claim 27 wherein the amount of the aromatic carboxylic acid is 0.2 to 5.0% by weight of the total amount of 3CaO.A?2O3.CaSO4.12H2O and the CaSO4 component.
30. The process as claimed in claim 1 wherein 3CaO.A?2O3.
3CaSO4.31-32H2O prepared is further carbonated to provide a carbonation product comprising a crystalline mixture of CaCO3, A?2O3.nH2O and CaSO4.2H2O.
3CaSO4.31-32H2O prepared is further carbonated to provide a carbonation product comprising a crystalline mixture of CaCO3, A?2O3.nH2O and CaSO4.2H2O.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP49132187A JPS5157693A (en) | 1974-11-15 | 1974-11-15 | Mukishitsuzairyono seiho |
| JP49133061A JPS5159094A (en) | 1974-11-18 | 1974-11-18 | Mukishitsuzairyono seiho |
| JP49142352A JPS5168625A (en) | 1974-12-10 | 1974-12-10 | Mukikeikokataino seiho |
| JP5179775A JPS51127117A (en) | 1975-04-29 | 1975-04-29 | Production method of inorganic cured object |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1070478A true CA1070478A (en) | 1980-01-29 |
Family
ID=27462692
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA239,933A Expired CA1070478A (en) | 1974-11-15 | 1975-11-17 | Process of producing calcium aluminate trisulfate hydrate and the dehydration product thereof |
Country Status (5)
| Country | Link |
|---|---|
| BR (1) | BR7507544A (en) |
| CA (1) | CA1070478A (en) |
| DE (1) | DE2551308B2 (en) |
| FR (1) | FR2291153A1 (en) |
| GB (1) | GB1535208A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4255398A (en) * | 1977-03-15 | 1981-03-10 | Hyogo Prefectural Government Of Japan | Novel ettringite whiskers, production and uses |
| JPS53137093A (en) * | 1977-03-15 | 1978-11-30 | Hiyougoken | Method of synthesizing ettringite |
| EP0006593B1 (en) * | 1978-06-22 | 1983-04-20 | Kubota Ltd. | Process for producing tobermorite and ettringite |
| JPS5590458A (en) * | 1978-12-26 | 1980-07-09 | Matsushita Electric Works Ltd | Manufacture of inorganic hardened body |
| DE2900613C2 (en) * | 1979-01-09 | 1988-01-21 | Mitsubishi Mining & Cement Co. Ltd., Tokyo | Process for the production of a fiber-reinforced, hardened plaster molding |
| FR2832401B1 (en) * | 2001-11-19 | 2004-12-10 | Carrieres Du Boulonnais | WHITE CEMENT, MANUFACTURING METHOD AND INSTALLATION |
| GB2586951B (en) * | 2019-06-12 | 2024-01-31 | Ardex Group Gmbh | A method and apparatus for processing water treatment residuals |
-
1975
- 1975-11-14 GB GB47007/75A patent/GB1535208A/en not_active Expired
- 1975-11-14 DE DE2551308A patent/DE2551308B2/en not_active Ceased
- 1975-11-14 BR BR7507544*A patent/BR7507544A/en unknown
- 1975-11-17 FR FR7535060A patent/FR2291153A1/en active Granted
- 1975-11-17 CA CA239,933A patent/CA1070478A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1535208A (en) | 1978-12-13 |
| BR7507544A (en) | 1976-08-10 |
| DE2551308A1 (en) | 1976-05-26 |
| AU8667775A (en) | 1977-04-07 |
| FR2291153A1 (en) | 1976-06-11 |
| FR2291153B1 (en) | 1980-05-30 |
| DE2551308B2 (en) | 1980-02-21 |
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