JPH0333078A - Manufacturing method for lightweight refractories - Google Patents

Abstract

PURPOSE:To obtain the wollastonite-series lightweight refractories utilizable as brick by mixing a calcareous raw material contg. portland cement with a siliceous raw material in a specified ratio, subjecting the mixture to compacting and hardening as the slurry coexistent with water and bubbles, subjecting the slurry to steam curing and thereafter executing heat treatment. CONSTITUTION:Calcareous raw material powder contg. portland cement and siliceous raw material powder are mixed so that the mole ratio of CaO/SiO2 is regulated to 0.8 to 1.1. The calcium silicate taw material powder is mixed with water and bubbles or is mixed with water and metallic aluminum into the state of slurry. The slurry is poured into a molding flask, which is compacted to harden and is thereafter subjected to steam curing at the high temp. of 190 to 240 deg.C under high pressure to obtain the green compact of a calcium silicate hydrate contg. xonotlite. The green compact is cut out into a prescribed shape, e.g. by the dimension of 230X114X65mm and is subjected to heating treatment to 700 deg.C so that the bulk density of a manufactured article is regulated to 0.3 to 1.0, by which the wollastonite-series lightweight refractories can be obtd.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing a wollastonite-based lightweight refractory used as a brick with excellent heat insulation and fire resistance.

[Conventional technology]

It has long been recognized that wollastonite has sufficient properties to be effective as a refractory.
: After melting the mixture at a weight ratio of 50 in an electric furnace,
A product as a refractory was obtained by pouring the molten metal into a mold, allowing the product to slowly cool within the mold, and then removing the mold. On the other hand, as a method of converting xonotrite particles into wollastonite particles by heating and dehydrating the xonotrite particles, JP-A-53-146997 describes
It is proposed that the heat treatment be performed at 1000°C for 1 hour, and furthermore, JP-A-55-109217 clearly states that the heat treatment is performed at 1000°C for 3 hours.

[Problem to be solved by the invention]

One way to obtain wollastonite as a refractory for construction is to melt a mixture of lime and silica stone in a weight ratio of 50:50 in an electric furnace, then pour the molten metal into a mold and allow it to slowly cool. There are cases where the product is obtained by removing the mold, and cases where the product is obtained by heating and dehydrating the xonotlite. However, after melting a mixture of lime and silica stone in a weight ratio of 50:50 in an electric furnace, the molten metal is poured into a mold,
When a wollastonite product is obtained by removing the mold after slow cooling, the bulk specific gravity of the obtained wollastonite refractory is 2.
．． Since there are 5 or more, it was difficult to reduce the weight of the structure. In addition, when obtaining wollastonite products by heating and dehydrating xonotlite, the slurry obtained by adding a large amount of water is molded and dried to make a lightweight body, so the product's flexural strength, compressive strength, etc. Its mechanical strength was low, and its use in construction was limited. In light of the above circumstances, the industrial world has strongly desired the emergence of lightweight refractories that have a bulk specific gravity of 1.0 or less and have sufficient material strength when used as structures. In response to the above-mentioned demands from the industrial world, the present invention aims to provide a lightweight refractory that has a bulk specific gravity of 1.0 or less and has sufficient material strength when used as a structure. purpose.

[Means to solve the problem]

In order to achieve the above purpose, the inventors, etc., after intensive study,
Air bubbles are mixed into the calcium silicate raw material for the raw material powder mixed so that the Cab/5tO2 molar ratio of the mixture of calcareous raw material powder containing Voltland cement and silicate raw material powder is 0.8 or more and 1.1 or less. Select a slurry in either a slurry state or a slurry state in which metal aluminum powder and water are added, mold and harden it in a mold, and then mold and harden the molded product at a temperature range of 190°C to 240°C. A molded body of calcium silicate hydrate containing xonotlite is produced by steam curing under high temperature and high pressure in 0.3 or more1.
The purpose was achieved by heating in a temperature range of 700°C or higher so that the temperature was 0 or lower.

[Effect]

In the present invention, the calcareous raw material powder containing Bortland cement and the silicic raw material powder are mixed so that the molar ratio of CaO/SiO2 is 0.8 or more and 1.1 or less. If the ratio is less than 0.8, the unreacted quartz portion will cause swelling due to phase transition during heat treatment, resulting in cracks on the product surface.
If it exceeds 1.1, amorphous C remains even after steam curing treatment.
This is because only SS togel is produced, and as a result, shrinkage during heating becomes large and the shape of the product cannot be maintained. The reason why we specified 190°C to 240°C as the processing temperature condition for steam curing is because if it is less than 190°C, the curing time will be longer and the productivity of the product will be lower, and if it exceeds 240°C, the pressure inside the autoclave will increase. Therefore, the equipment cost of the steam curing treatment device becomes unnecessarily high, and the effect of shortening the time required for the curing treatment becomes extremely small. The bulk specific gravity of the product was specified as 0.3 or more and 1.0 or less.
If the bulk specific gravity is less than 0.3, it will be difficult to obtain mechanical strength as a material for construction, and if it exceeds 1°0, the temperature will exceed 700°C.
This is because the dehydration process cannot be carried out smoothly during heating, resulting in cracks on the surface of the product. The reason for using Bolland cement is that it improves the moldability when the raw material slurry is molded and hardened, and furthermore, the work of cutting out the molded hardened body can be done smoothly, and the cost of raw materials can be significantly reduced. After cutting the molded calcium silicate hydrate containing xonotlite into a predetermined shape, the bulk specific gravity of the product is 0°3 or more and 1.0
The reason for heating in a temperature range of 700°C or higher as shown below is that heating below 700°C will not smoothly convert xonotlite to wollastonite.
This is because it is not sufficient to ensure the mechanical strength of the product. The bulk specific gravity of the product can be adjusted as appropriate by adjusting the amount of aluminum powder used as a blowing agent or by adjusting the amount of air bubbles to be mixed into the product. As described above, by carrying out the present invention, high quality lightweight refractories can be easily obtained in a short processing time.

【Example】

(Example 1) 42 parts by weight of silica stone containing 94.5% by weight of SiO2, 12 parts by weight of quicklime containing 96.9% by weight of Ca0, and slaked lime containing 72.6% by weight of Ca0. 30
Part by weight, 64.8% by weight of Ca0 and sio
Voltland cement 1 containing 21° 5% by weight of
For 100 parts by weight of raw material powder composed of 6 parts by weight, A
0.030 parts by weight of I-grain powder and 67 parts by weight of water were added to make a slurry, and the slurry thus created was further adjusted to have a Cao/SiO2 molar ratio of 1.09, and then a 150 mm x 150 mm x 400 mm The above slurry was poured into a mold, foamed and hardened, and after curing in an autoclave at 200°C for 24 hours, a mold of 230 mm x 114 m
A sub-shaped brick cut out with dimensions of m x 65 mm was placed in an electric furnace, heated to 700°C, heated at a heating rate of 100°C/h to 900°C, held for 30 minutes, and heated for 1 hour. The mixture was returned to room temperature to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.7, a compressive strength of 40 kgf/cr+f, and the strength of wollastonite obtained using X-ray diffraction method is moderate, and there are no cracks on the surface of the product. was also not recognized. (Example 2) 46 parts by weight of silica stone containing 94.5% by weight of 8102 min, 15 parts by weight of quicklime containing 96.9% by weight of Ca0 min, and slaked lime 111i containing 72.6 wt% of Ca0 min.
0.170 parts by weight of AI granule powder for 100 parts by weight of raw material powder composed of 28 parts by weight of Voltland cement containing 64.8% by weight of 0% Ca and 21.5% by weight of 810□. and 64 parts by weight of water to form a slurry.
/SiO□ molar ratio was adjusted to 0189, then 1
The above slurry was poured into a mold of 50 mm x 150 mm x 400 mm, foamed and hardened, and after curing in an autoclave at 210°C for 24 hours, a mold of 230 mm x 114 mm x
A sub-type brick cut to a size of 65 nm was charged into an electric furnace, heated to 700°C, and heated to 90°C at a heating rate of 100°C/h.
After heating to 0° C. and holding for 30 minutes, the temperature was returned to room temperature over 1 hour to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.3 and a compressive strength of 15 K g f / cd
In addition, the strength of the wollastonite obtained using the X-ray diffraction method was strong, and no cracks were observed on the surface of the product. (Example 3) 48 parts by weight of silica stone containing 94.5% by weight of SiOx, 10 parts by weight of quicklime containing 96.9% by weight of Ca0, and 32 parts by weight of slaked lime containing 7266% by weight of Ca0.
0.028 parts by weight of AI granule powder for 100 parts by weight of raw material powder composed of 10 parts by weight of Bortland cement containing 64.8% by weight of Ca0 content and 21.5% by weight of Stow content. and 70 parts by weight of water to form a slurry, and furthermore, the Ca
After adjusting the o/5iOt molar ratio to 0.89,
Pour the above slurry into a 150mm x 150mm x 400mm mold, foam and harden it, and heat it at 200°C for 24 hours.
After autoclave curing for hours, 230mmX114
A sub-shaped brick cut out with dimensions of mm x 65 mm was placed in an electric furnace, heated to 700°C, then heated to 900'c at a rate of 100°C/h, held for 30 minutes, and heated for 1 hour. The mixture was returned to room temperature to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.7 and a compressive strength of 33 K g f /
CD, and the strength of the wollastonite obtained using the X-ray diffraction method was strong, and no cracks were observed on the surface of the product. (Example 4) 44 parts by weight of silica stone containing 94.5% by weight of SiO2, 11 parts by weight of quicklime containing 96.9% by weight of Ca0, and slaked lime containing 72.6% by weight of Ca0. 42
0.065 parts by weight of AI granule powder for 100 parts by weight of raw material powder composed of 3 parts by weight of Bortland cement containing 64.8% by weight of Ca0min and 21.5% by weight of 5in2min. and 64 parts by weight of water to form a slurry, and furthermore, CaO of the slurry thus prepared was added.
/ Si Ox molar ratio was adjusted to 1.10, the slurry was poured into a 150 mm x 150 mm x 400 mm mold, foamed and hardened, and after curing in an autoclave for 12 hours at 220 ° C., the mold was molded into a 230 mm x 114 m mold.
A sub-shaped brick cut out with dimensions of m x 65 mm was placed in an electric furnace, heated to 700°C, heated at a heating rate of 100°C/h to 900°C, held for 30 minutes, and heated for 1 hour. The mixture was returned to room temperature to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.5 and a compressive strength of 35 K g f /
cr rrr, and the strength of the wollastonite obtained using the X-ray diffraction method was moderate, and no cracks were observed on the surface of the product. (Actual Vaginal Example 5) 46 parts by weight of silica stone containing 94.5% by weight of SiO2, 10 parts by weight of quicklime containing 96.9% by weight of Ca0, and 72.6% by weight of Ca0. Slaked lime 26
Part by weight, 64.8% by weight of Ca0 and S L 0
2 minutes is 21.51! For 100 parts by weight of raw material powder composed of 18 parts by weight of Voltland cement containing % of
0.014 parts by weight of AI grain powder and 59 parts by weight of water were added to form a slurry, and further 1. After adjusting the CaO/SiO2 molar ratio of the slurry created in this way to 0.91, f 50mmX15QmmX400m
Pour the above slurry into a mold of m and allow it to foam and harden.
After autoclaving at 90℃ for 24 hours, 230℃
A sub-type brick cut out with dimensions of mm x 114 mm x 65 mm was charged into an electric furnace, heated to 700°C, and then heated to 100°C/
The refractory was heated to 900° C. at a heating rate of h, held for 30 minutes, and then returned to room temperature over 1 hour to obtain a light Ik refractory. This lightweight refractory has a bulk specific gravity of 0.9 and a compressive strength of 45.
K g f / cr d and the strength of the wollastonite obtained using the X-ray diffraction method was moderate, and no cracks were observed on the surface of the product. (Example 6) 50 parts by weight of silica stone containing 94.5% by weight of S i 02min, 9 parts by weight of quicklime containing 96.9% by weight of Ca0min, and 72°6% by weight of Ca0min. 0.021 parts by weight of A1 powder was added to 100 parts by weight of raw material powder composed of 30 parts by weight of slaked lime and 11 parts by weight of Bortland cement containing 64.8% by weight of 0% Ca and 21.5% by weight of 8102%. parts by weight and 71 parts by weight of water were added to form a slurry, and the Ca0
/SiO2 molar ratio was adjusted to 0.81, then 1
The above slurry was poured into a mold of 50 mm x 150 mm x 400 mm, foamed and hardened, and after curing in an autoclave at 210°C for 24 hours, a mold of 230 mm x 114 mm x 6
A sub-shaped brick cut to a size of 5 mm was charged into an electric furnace, heated to 700°C, and then heated to 900°C at a heating rate of 100°C/h.
After heating to ℃ and holding for 30 minutes, the mixture was returned to room temperature over 1 hour to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.8 and a compressive strength of 26 K g f / cr
t, the strength of the wollastonite obtained using the X-ray diffraction method was moderate, and no cracks were observed on the surface of the product. <Example 7> 46 parts by weight of silica stone containing 94.5% by weight of Si0w, 10 parts by weight of quicklime containing 96.9% by weight of Ca0, and 41 parts by weight of slaked lime containing 72.6% by weight of Ca0. part, 64.8% by weight of Ca0 min and 2 min of 5 in2 min.
30 parts by weight of water was added to 100 parts by weight of raw material powder composed of 3 parts by weight of Bortland cement containing 1.5% by weight, and the CaO/ S i 02 molar ratio is 1.01
At the same time, on the other hand, prepare air milk with a specific gravity of 0.05 by mixing 5 parts by weight of an algenyl succinic acid foaming agent and 100 parts by weight of water, and mix this air milk with the above. A slurry containing 2.5% of air bubbles by volume was obtained by mixing with the paste. And 150mmX
The above volume ratio is 2.5 in a 150mm x 400mm mold.
% of air bubbles was poured into the slurry and cured in an autoclave for 24 hours at 230°C.
A sub-shaped brick cut out with dimensions of 30 mm x 114 mm x 65 mm was charged into an electric furnace, heated to 700°C, and heated to 100°C.
The material was heated to 900° C. at a temperature increase rate of ° C./h, held for 30 minutes, and then returned to room temperature over 1 hour to obtain a lightweight and durable product. This lightweight refractory has a bulk specific gravity of 0.3 and a compressive strength of 1.
3 K g f / cr rd, and the intensity of wollast day 1 obtained using X-ray diffraction method is intense,
No cracks were observed on the surface of the product. (Example 8) 41 parts by weight of silica stone containing 94.5% by weight of 5i02min, 11! parts by weight of quicklime containing 96.9% by weight of Ca, 0min, and 72.61!% by weight of Ca0min. Slaked lime 15
parts by weight, 64.8% by weight of Ca0 and S i O
Boltland cement 3 containing 21° 5% by weight of
30 parts by weight of water was added to 100 parts by weight of raw material powder composed of
1, and on the other hand, prepare air milk with a specific gravity of 0.05 by mixing 5 parts by weight of an algenyl succinic acid foaming agent and 100 parts by weight of water. Mixed with the above paste to give a volume ratio of 0.1%
A slurry containing air bubbles was obtained. And 150mm
x 150mm x 400mm mold with the above volume ratio of 2.
The above slurry containing 5% air bubbles was poured and cured, and after curing in an autoclave at 200°C for 36 hours,
A sub-type brick cut out with dimensions of 230 mm x 114 mm x 65 mm was charged into an electric furnace, heated to 700°C, and heated to 100°C.
It was heated to 9QO°C at a heating rate of °C/h, held for 30 minutes, and then returned to room temperature over 1 hour to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 1.0 and a compressive strength of 60.
K g f / cr I? In addition, the strength of the wollastonite obtained using the X-ray diffraction method was strong, and no cracks were observed on the surface of the product. (Comparative Example 1) 100 parts by weight of raw material powder composed of 42 parts by weight of silica stone containing 94.5% by weight of Sin 2 and 9 parts by weight of raw Bortland cement containing 96.9% by weight of Ca 0. To the slurry, 0.102 parts by weight of AI grain powder and 63 parts by weight of water were added, and the CaO/SiO2 molar ratio of the slurry thus created was adjusted to 1.19. After, 150mmX150mmX400m
Pour the above slurry into a mold of m and allow it to foam and harden.
After autoclaving at 240°C for 18 hours, 23
A sub-type brick cut out with dimensions of 0 mm x 114 mm x 65 mm was charged into an electric furnace, heated to 700°C, and then heated to 100°C/
The sample was heated to 900° C. at a heating rate of h, held for 30 minutes, and then returned to room temperature over 1 hour to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.4 and a compressive strength of 14 K.
g f / c td, and the strength of the wollastonite obtained using the X-ray diffraction method was weak, and many cracks were observed on the surface of the product. (Comparative Example 5) SiOz content is 94.5! 52 parts by weight of silica stone containing 1% of j and 8 parts of quicklime containing 96.9% by weight of Ca0
20 parts by weight of slaked lime containing 72.6% by weight of Ca0 min, and 20 parts by weight of Bortland cement containing 64.8 wt% of Ca0 min and 21.5 wt% of 5if2 min. To 100 parts by weight of the powder, 0.107 parts by weight of AI grain powder and 60 parts by weight of water were added to make a slurry, and the CaO
/ S i O2 molar ratio was adjusted to 0.71, the above slurry was poured into a 150 mm x 150 mm x 400 mm mold, foamed and hardened, and heated at 230°C for 12
After autoclave curing for hours, 230mmX114
A sub-shaped brick cut out with dimensions of mm x 65 mm was charged into an electric furnace, heated to 700°C, heated at a heating rate of 100°C/h to 900°C, held for 30 minutes, and then brought to room temperature over an hour. A lightweight refractory material was obtained by returning it to This lightweight refractory has a bulk specific gravity of 0.4 and a compressive strength of 7 K g f/c
/, and the strength of the wollastonite obtained using the X-ray diffraction method was weak, and many cracks were observed on the surface of the product. (Comparative Example 6) Silica stone 521JLM containing 94.5% by weight of Sin2min
9 parts by weight of quicklime containing 96.9% by weight of Ca0 min, 36 parts by weight of slaked lime containing 72.6 wt% of Ca0 min, 64.8 wt% of Ca0 min and S i O2
0.044 parts by weight of AI granule powder and 70 parts by weight of water are added to 100 parts by weight of raw material powder composed of 3 parts by weight of Bortland cement containing 21.5% by weight to form a slurry, Furthermore, the Ca of the slurry prepared in this way
After adjusting the fI so that the b/SiO2 molar ratio was 0.79, the above slurry was poured into a 150 mm x 150 mm x 400 mm mold, foamed and hardened, and heated at 200°C for 4 hours.
After 8 hours of autoclave curing, 230mm x 11
A sub-shaped brick cut out with dimensions of 4rnm x 65mrn was charged into an electric furnace, heated to 700℃, heated at a heating rate of 100℃/h to 900℃, held for 30 minutes, and then heated to room temperature over 1 hour. A lightweight refractory material was obtained by returning it to This lightweight refractory has a bulk specific gravity of 0.6 and a compressive strength of 18 kg f.
/ crrf, and the strength of the wollastonite obtained using the X-ray diffraction method was weak, and many cracks were observed on the surface of the product. (Comparative Example 7) 52 parts by weight of silica stone containing 94.5% by weight of 5if2, 9 parts by weight of quicklime containing 96.9% by weight of Ca0, and 36 parts by weight of slaked lime containing 72.6% by weight of Ca0. part, 64.8% by weight of Ca0min and 21% of 5iOz
．． 30 parts by weight of water for 100 parts by weight of raw material powder composed of 3 parts by weight of Boltland cement containing 51% by weight of E! ! The Cab/St2 molar ratio of the base thus prepared was adjusted to 0.79, and on the other hand, alkenyl succinic acid was added to make a paste. Prepare air milk with a specific gravity of 0.05 by mixing 5 parts by weight of foaming agent and 100 parts by weight of water, and mix this air milk with a specific gravity of 0.05 with the above paste to give a volume ratio of 0.9%. Obtain a slurry containing air bubbles and carry it for 150m.
The above slurry was poured into a mold of m x 150 mm x 400 mm, foamed and hardened, and after curing in an autoclave for 24 hours at 220 ° C., it was molded into a mold of 230 mm x 114 mm x 65 mm.
The sub-type bricks cut to the dimensions of are charged into an electric furnace, and 70
It was heated to 900°C at a rate of temperature increase f&100°C/h to 0°C, held for 30 minutes, and then returned to room temperature over 1 hour to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.5 and a compressive strength of 14K.
gf/crr? In addition, the strength of the wollastonite obtained using the X-ray diffraction method was weak, and many cracks were observed on the surface of the product. (Comparative Example 8) Silica stone 42 weight J containing 94.5% by weight of S i O2
i part and quicklime 11 containing 96.9% by weight of Ca0
Slaked lime 4 containing 72.6% by weight and Ca0 min.
5 parts by weight, 64.8% by weight of Ca0min and Si
30 parts by weight of water was added to 100 parts by weight of raw material powder composed of 2 parts by weight of Boltland cement containing 21.5 fjL of O2 content, and the paste prepared in this way was further added. CaO/5i02 molar ratio is 1
．． 19, and on the other hand, prepare air milk with a specific gravity of 0.05 by mixing 5 parts by weight of an alkenyl succinic acid foaming agent and 10011 parts by weight of water.
The above paste was mixed with this air milk with a specific gravity of 0.05 to obtain a slurry containing 0.7% of air bubbles by volume, and the slurry was poured into a mold of 150 m x 150 mm x 400 mm to foam and harden. 1 in °C
After 8 hours of autoclave curing, 230mm x 11
A sub-shaped brick cut out with dimensions of 4 mm x 65 mm was placed in an electric furnace, heated to 700°C, heated at a rate of 100°C/h to 900°C, held for 30 minutes, and then heated for 1 hour. The mixture was returned to room temperature to obtain a lightweight refractory. This lightweight refractory has a bulk specific gravity of 0.6 and a compressive strength of 16.
K g f / crtr, and the strength of the wollastonite obtained using the X-ray diffraction method was weak, and many cracks were observed on the surface of the product. Table 1 shows Examples 1 to 6 and Comparative Examples 1 to 6, and Table 2 shows Examples 7 to 8 and Comparative Examples 7 to 8. In addition, cracks on the product surface are determined by the visual inspection method of JI 5A5416 at a distance of 60cm1l? Those that were not noticeable when visually inspected were considered good. (Margins below this page)

【Effect of the invention】

By implementing the present invention, high quality lightweight refractories can be easily obtained in a short processing time, and bricks of any shape can be efficiently produced by manipulating the cut shape, contributing to the industry. There is something big to do.

Claims (1)

[Claims] Calcareous raw material powder containing Voltland cement and silicic raw material powder are mixed to form a powder with a CaO/SiO_2 molar ratio of 0.8.
Calcium silicate raw material powder adjusted to 1.1 or less is prepared, and the raw material powder is prepared in a slurry state in which water and air bubbles are co-mixed and in a slurry state in which water and metal aluminum powder are mixed. By making one of the slurry state appear, injecting the slurry into the mold and molding and hardening, and then curing the molded and hardened product with steam under high temperature and high pressure in the temperature range of 190 ° C to 240 ° C. , after producing a molded body of calcium silicate hydrate containing xonotlite and cutting the molded body of calcium silicate hydrate containing xonotlite into a predetermined shape, the bulk specific gravity of the product is 0.3 or more 1
．． A method for producing a lightweight refractory, characterized by heating in a temperature range of 700°C or higher so that the temperature is 0 or lower.