JPH0692257B2 - Method for producing pyroxene-based crystallized glass - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing pyroxene-based crystallized glass.

[Prior art] There is pyroxene-based crystallized glass as a building material such as wall material, but the desired hydroxyl group and the degree of redox change in the glass due to the working conditions at the time of melting, raw material type and brand, etc. Since it is difficult to obtain a rough stone pattern, there were many restrictions such as adjustment of the gas concentration in the glass during melting, adjustment of the gas concentration in the atmosphere, and specification of the raw material brand.

[Problems to be Solved by the Invention] The present invention is a problem in the production of crystallized glass by using pyroxene-based crystals, and is a target composition without any restriction such as the adjustment of the gas concentration in the glass and the melting furnace and the specification of the raw material brand. The present invention aims to provide a method for producing pyroxene-based crystallized glass having a natural stone pattern by melting and shaping the glass.

[Means for Solving Problems] In the present invention, SiO ₂ 55 to 68 and Al ₂ O _{3 3} to 1 are substantially expressed in weight%.
5, SiO ₂ + Al ₂ O ₃ 62-78, CaO3-8, MgO8-13, CaO + MgO
_{11~19, Na 2 O6~12, Li 2} O0~3, K 2 O0~5, Na 2 O + Li 2 O
_{+ K 2 O6~12, TiO 2 0~4} , ZnO0~10, B 2 O 3 0~6, P 2 O 5 0
~ 3, F0.1-1.5, TiO ₂ + F0.2-5, and a glass having a composition in which the weight ratio MgO / CaO is more than 2/3 are molded into a predetermined shape, and the molded body is heated to produce pyroxene-based crystals. A method for producing a crystallized glass that produces

In the present invention, the crystallized glass produced contains pyroxene crystals in an amount of about 20 to 50% by weight.

The main elements of this pyroxene crystal are the crystals of chemical composition MgSiO ₃ called ganka or pyroxene, and the chemical composition CaMg called pyroxene.
It is a crystal of Si ₂ O ₆ and a crystal in which a part of Mg and Si of pyroxene is replaced by Al.

The reasons for limiting the glass composition of the molded product used in the present invention are as follows.

SiO ₂ serves as a pyroxene crystal component and a glass phase component. Si
If O ₂ <55%, SiO ₂ > 68%, it is difficult to obtain a product of the crystallized glass, and it is difficult to form a plate by the roll-out method in terms of viscosity.

Al ₂ O ₃ is one of the action of improving the weather resistance, the action of promoting the formation of crystals, and one of the pyroxene crystal constituent components. Al ₂ O ₃ <3
%, These effects are insufficient. When Al ₂ O ₃ > 15%, other crystalline forsterite and cordierite are formed, and the meltability becomes poor.

When SiO ₂ + Al ₂ O ₃ > 78%, the glass meltability deteriorates and S
When iO ₂ + Al ₂ O ₃ <62%, the weather resistance of the glass decreases.

CaO is a component of pyroxene crystals. When CaO <3%, the generation of crystals is small, and when CaO> 8%, the generation of crystal nuclei is suppressed, and the crystal growth from the inside is not achieved.

MgO is a component of pyroxene crystals. When MgO <8%, it is difficult to form the crystal, crystals other than the crystal (wollastonite, anorthite) are generated, the generation of the crystal is suppressed, and crystal growth does not occur from the inside, so the strength decreases. To do. When MgO> 13%, enstatite is likely to be formed when the molten glass is molded into a plate shape, and the molding is difficult.

If CaO + MgO> 19%, cracks tend to occur, while CaO + M
When gO <11%, the amount of produced crystals is small and the strength is low.

Na ₂ O improves the meltability of the raw material and the formability into a plate, and accelerates crystal growth. When Na ₂ O <6%, the meltability is poor, ordinary tank melting is difficult, and moldability is also reduced. When Na ₂ O> 12%, the viscosity is too low, the moldability is adversely affected, and the weather resistance is degraded.

Similar to Na ₂ O, K ₂ O improves the meltability and plate formability, and improves the weather resistance by the combined alkali effect (Na ₂ O + k ₂ O). When k ₂ O> 5%, crystals are generated during molding and the price is high.

Like Na ₂ O, Li ₂ O improves solubility and plate formability, and improves weather resistance by the combined alkali effect (Na ₂ O + Li ₂ O). Prices are high for Li ₂ O> 3%.

In addition, if Na ₂ O + K ₂ O + Li ₂ O is less than 6%, the solubility decreases, and if it exceeds 12%, the weather resistance decreases. TiO ₂ and F described below are crystal nucleating agents. These components have a function of generating crystals from the inside of the glass and improving the strength of the crystallized glass. Of these, TiO ₂ has a function of growing crystals to a size excellent in appearance as a natural stone pattern. When TiO ₂ > 4%, the crystals are colored grayish purple.

ZnO is not an essential component, but its addition can improve chemical resistance and strength of the crystallized glass. When Zn0> 10%, the meltability deteriorates, so that other crystals (zinc spinel) are further formed and colored dark blue. ZnO is particularly preferably 0 to 8% in the above range.

B ₂ O ₃ is not an essential component, but promotes meltability and reduces viscosity. When B ₂ O ₃ > 6%, phase separation of the glass is likely to occur, which delays the crystallization treatment time after molding and, in addition, causes fine cracks in the product after crystallization. B ₂ O ₃ is 0 to 0 in the above range.
5% is particularly preferred.

P ₂ O ₅ promotes meltability and promotes crystal nucleus formation. P ₂ O ₅ ＞
On the contrary, 3% delays the growth of crystals and delays the crystallization treatment time after molding.

F promotes meltability and is a crystal nucleating agent for pyroxene-based crystallized glass as described above. When F> 1.5%, the amount of F compound increases and the strength of the product decreases. In addition, by adjusting the F concentration in this range, it is possible to set the crystal grain size in the range from natural stone patterns to plain fine crystals. If it is less than 0.1%, the number of crystals growing from the surface increases and the product strength decreases.

If F + TiO ₂ is less than 0.2%, it is difficult to form crystals, and if it exceeds 5%, devitrification is likely to occur during glass molding.

If the MgO / CaO weight ratio is less than 2/3, wollastonite crystals are generated and cracks easily occur.

In the present invention, it is preferable that the total amount of the above components is 96% or more, and if the balance is less than 4%, powder of manganese, cobalt, iron, nickel, copper or the like or an oxide powder thereof is added as a colorant. , You can make it your favorite color.

In producing a glass molded product having such a composition, the respective raw materials are blended so as to obtain a target composition, a batch is prepared, and the mixture is heated to 1400 to 1500 ° C. in a melting furnace to be melted and clarified. Next, the molten glass is cooled to about 1300 ° C. and molded into a predetermined shape. When forming a sheet glass, although not particularly limited, a method of continuously forming a ribbon having a predetermined thickness by a roll-out method and then slowly cooling the ribbon into a predetermined size is a productivity method. It is desirable from the aspect.

In order to generate crystals in such a compact, it is desirable to perform the following heat treatment.

The temperature is raised to a temperature at which crystals grow so as not to damage the compact, and the temperature is maintained for 3 to 5 hours in a normal atmosphere. As a result, pyroxene crystals are formed as main crystals in the glass. The optimum temperature for growing the crystal is 950 to 1050 ° C. Hold the temperature at 650 to 780 ° C for 120 to 240 minutes during the temperature raising step or reduce the temperature raising rate in the temperature range to generate fine crystals. You can The size of the crystal plaque generated by this method is 0.1.
~ 4 m / m, and the amount of crystals finally produced is 30
~ 40% by weight.

[Example] According to a conventional method, silica sand was used as an SiO ₂ source so that the target composition shown in Table 1 was obtained.
Al ₂ O ₃ MinamotoToshi alumina powder, CaO source and limestone, MgO MinamotoToshi magnesium hydroxide, Na ₂ O MinamotoToshi soda ash, K ₂ O Shun Minamoto potassium carbonate, Li ₂ O Shun Minamoto lithium carbonate, TiO ₂ Shun Minamoto dioxide A batch was prepared according to the intended glass composition by using titanium powder, zinc oxide as a ZnO source, borax as a B ₂ O ₃ source, calcium phosphate as a P ₂ O ₅ source, and mirabilite and carbon as fining agents. 5 kg of this batch was put into a platinum crucible, melted at 1450 ° C. for 5 hours, press-formed into a plate and cooled. The formed plate glass was placed on a base made of a refractory material to which alumina powder was dispersed, placed in a heat treatment furnace, heated at 50 ° C / h, and crystallized at 1000 ° C for 4 hours.

Next, the surface of this plate glass was roughly polished with silica sand, and gloss was given with alumina powder. The devitrification temperature, the bending strength and the crystal size measured for these glasses are also shown in the table. As is apparent from the table, in the present invention, the crystal size of 0.1 to 4 m / m can be adjusted by adjusting the additive of F. You can operate freely between them. The other properties of the glass were the same as those of the crystallized glass material obtained by the conventional technique, and could be sufficiently used as a wall material.

[Effects of the Invention] Since the crystallized glass according to the present invention has crystals developed in various directions irrespective of the glass surface, it is produced by forming the glass melt into a plate shape by a roll-out method or the like, crystallizing it, and polishing it as it is. it can. Therefore, the step of granulating the glass and putting it into the mold can be simplified. In addition, by eliminating the above steps, bubble defects can be greatly reduced and the quality of the wall material is improved.

By using F as a nucleating agent in addition to TiO ₂ and P ₂ O ₅ and adjusting the amount thereof, the size of the crystal plaque can be freely set between 0.1 and 4 m / m.

Since the glass melting conditions can be set separately from the crystal grains of the final product, the internal bubble defect, which is one of the defects, can be greatly improved.

By allowing F to remain appropriately, it is possible to improve workability such as cutting and polishing of glass after crystallization by heat treatment.

Further, since the glass has a low devitrification temperature of 1250 ° C., it can be formed by an ordinary roll-out method, so that there are few restrictions on manufacturing conditions. In addition, since fine crystal grains are obtained even when vitrified due to oxidation, there is an advantage that colored crystallized glass can be easily obtained.

Claims (1)

[Claims] Claims: 1. SiO ₂ 55-68, Al ₂ O ₃ 3 substantially in weight percent.
_{~15, SiO 2 + Al 2 O} 3 62~78, CaO3~8, MgO8~13, CaO +
_{MgO11~19, Na 2 O6~12, Li 2} O0~3, K 2 O0~5, Na 2 O + L
_{i 2 O + K 2 O6~12,} TiO 2 0~4, ZnO0~10, B 2 O 3 0~6, P 2 O
Glass having a composition of 50 to 3, F0.1 to 1.5, TiO ₂ + F0.2 to ₅ and a weight ratio MgO / CaO of greater than 2/3 is molded into a predetermined shape, and the molded body is heated to produce pyroxene. A method for producing crystallized glass that produces a system crystal.