CN1180672A - A kind of glass-ceramic formula and its manufacturing process - Google Patents

Abstract

A formula of glass-ceramics and a manufacturing process thereof belong to the field of building materials. The formula of this glass-ceramic can be divided into two categories, the first category is slag: the raw materials used are: slag, quartz sand, feldspar, limestone, fluorite, dolomite, talc. The second type of sediment: the raw materials used are sediment, quartz sand, feldspar, soda ash, limestone, dolomite, barite, fluorite. Its manufacturing process has two kinds of integral crystallization method and sintered crystallization method. The crystallized glass of the present invention has the characteristics of high crystallization rate, no deformation, no cracking, few surface pores and high strength.

Description

A kind of glass-ceramic formula and its manufacturing process

The invention relates to the manufacture of a kind of multi-phase glass-ceramic decorative material characterized by high density, low porosity and resistance to cracking, and belongs to the field of building materials.

In the production of glass-ceramic materials, the prepared sintered glass-ceramic plates often contain more or less pores, which reduces the strength and other properties of the finished product; after grinding and polishing, the pores on the surface will seriously affect its appearance. And decorative effects, and reduce the yield of materials. How to reduce the porosity and increase the density of glass-ceramic products has actually become one of the main problems faced in the production of sintered glass-ceramics. For the purpose of devitrification of the glass matrix, a large amount of network adjustment and modifier ions and a large number of crystal nucleating agents are added, resulting in loose glass network structure and shortened material properties, so it is difficult to control the crystallization process, often due to excessive crystallization Uneven stress leads to cracking.

The purpose of the present invention is to provide a formula of glass-ceramics, which can make the glass less likely to crack during the production process of the glass-ceramics and reduce the porosity of the glass.

The purpose of the present invention is achieved by adjusting the composition formula of the glass. The prescription of crystallized glass of the present invention is to make the glass precursor of manufacturing glass-ceramic have at least two crystallization peaks (Tc ₁ , Tc ₂ ) and the temperature between the two crystallization peaks and between the glass transition temperature (Tg) The intervals are larger.

Specifically, the glass-ceramic formula of the present invention has two classes:

The first type of slag: its components are (% by weight):

SiO ₂ 44~60, Al ₂ O ₃ 3~10, CaO 10~21

MgO 3~7, ZnO 0.5~3.0, R ₂ O(Na ₂ O+K ₂ O) 3~7

FeO+ _{Fe2O3 0.1} ～24.0 S 0.2～1.5

B ₂ O ₃ 0~8, reducing agent carbon: 0~1, F ₂ 1~3

Cr ₂ O ₃ 0～1.5 Sb ₂ O ₃ 0～1

Among them, RO (CaO+MgO+ZnO+FeO) should account for 25-38%.

The Cr ₂ O ₃ or ZnS added therein acts as a coloring agent and crystal nucleating agent.

The raw materials used are: slag, quartz sand, feldspar, limestone, fluorite, dolomite, talc.

The second class of silt class: its component is (weight %)

SiO ₂ 44～65 Al ₂ O ₃ 4～11 CaO 10～20

MgO 0～4 ZnO 0～2.5 B ₂ O ₃ 0～6

R ₂ O(Na ₂ O+K ₂ O) 10～18 FeO+Fe ₂ O ₃ 0.1～2.0

A certain amount of ZnS or TiO ₂ can be added as coloring agent and crystal nucleating agent according to color requirements. The raw materials used are sediment, quartz sand, feldspar, soda ash, limestone, dolomite, barite, fluorite.

The technological process of producing glass-ceramics with the formula of glass-ceramic of the present invention, according to integral crystallization or sintering crystallization is respectively:

1. Overall crystallization method

According to the raw materials of the above formula, glass plates are made by melting, calendering, pressing or casting techniques, and then annealed at 550-620 ° C, and then gradually cooled to room temperature.

Raise the obtained glass plate at a rate of 150-350°C/hour to near T _C1 and keep it warm for 0.5-1 hour (it is not ruled out to keep it warm for a period of time near the softening point of the glass), and then raise it to Temperature higher than Tc ₂ 50-200°C for about 1.5 hours, and then cooling down to obtain a glass-ceramic plate.

2. Burning crystallization method:

The glass melt prepared according to the above formula is poured into water, quenched into slag, and the glass slag with a particle size of 1-15mm is put into and stored in a mold with an ideal shape, and the temperature is not higher than 400°C/hour. The rate rises to slightly lower than T _C1 and keeps warm for 0.5 to 1 hour (do not rule out keeping warm for a period of time near the softening point of the glass), and then rises to 1000 ℃ to 1120 ℃ at a rate not higher than 300 ℃ / hour The temperature is kept for about 1.5 hours, so that the glass frit softens and deforms and melts and combines with each other to form a whole. At the same time, crystals are precipitated from the surface of the glass slag, thereby obtaining crystallized glass.

According to the raw material formula designed by the inventive method, because the glass obtained contains at least two crystallization peaks, and the interval between the crystallization peaks and between the glass transition temperature Tg is relatively large, thus when we carry out crystallization treatment to it, in After keeping warm near Tc ₁ , due to the action of an appropriate crystal nucleating agent, the nucleation and precipitation of the first crystal phase will appear in the glass plate. After continuing to heat up, the first crystal phase will grow on the interface of the first crystal phase 2. The third type of crystal constitutes a complex phase structure. Because a large number of crystals are avoided in the glass at the same time, the glass has a relaxation process in each stage of the crystallization heat treatment process, and the generated crystal phases form a matching multi-phase structure, so the obtained glass-ceramic plate has a high crystallization rate. , not easy to deform, no cracking, high strength characteristics.

In the case of sintering and crystallization, a part of crystal phase 1 is formed in the glass slag when it is treated near T _C1 , but because it is uniformly nucleated and grown inside, and the proportion is relatively small, the majority of the slag is still glass. It can still flow during the subsequent heating and sintering, so that during the sintering process, the particles can fuse with each other through flow and mass transfer, clear the pores between the particles, and avoid the sintered glass-ceramics often due to its first surface devitrification The particles caused by the surface are prematurely solidified, difficult to sinter, and the pores are not easy to eliminate. At the same time, the crystalline phases grown on the embryo formed earlier and the crystalline phases grown on the surface form a tightly combined complex phase structure during the sintering and crystallization process, achieving a sintered type with high crystallization rate, less pores and beautiful appearance. Glass-ceramic.

Example 1:

A mixture of the following ingredients was melted at 1450 °C for 100 min to prepare a molten glass:

Lead-zinc slag Quartz sand Feldspar Fluorspar C ₂ O ₃ CuO Calcite weight% 56 20 10 6 ≤1 1 6

The resulting glass was annealed at 600°C. It is subjected to stage heat treatment, the first stage heat preservation temperature is 780 ℃, heat preservation for half an hour, at this time, a certain amount of chromite and ordinary pyroxene crystal phases are precipitated in the glass. Raise the temperature to 1040°C and keep it warm for 1 hour, and then anneal and cool to room temperature to obtain a glass-ceramic plate whose main crystal phase is pyroxene and wollastonite. Under the electron microscope, the complex phase structure of wollastonite crystals and various pyroxene phases can be observed after the second stage of heat preservation. After surface grinding and polishing, it presents a dark and shiny appearance similar to dark black marble, which can be used as a high-grade finishing material.

Example 2:

A mixture of the following ingredients was melted at 1530°C for 3 hours to prepare the glass:

Shandong Yellow River Sediment Feldspar Calcite Na ₂ CO ₃ % by weight 66 10 16 8

A certain amount of ZnS and TiO ₂ are added to the batch material as crystal nucleating agents, and the molten glass is water-quenched to obtain a small glass frit. Store the 1-15mm glass frit in the mold box and send it into the tunnel kiln to keep it at 800°C for 45 minutes, then raise the temperature to 1100°C and keep it for 1 hour, then gradually cool down to room temperature, grind and polish to get green crystal flowers A crystallized glass plate with almost no pores on the surface. The analysis shows that the crystalline phases precipitated in the first stage are devitrite and a small part of anorthite. After the second stage treatment, a large amount of wollastonite and a part of nepheline are precipitated in the plate. The radial and short columnar wollastonite and nepheline precipitated from the surface together with the previously precipitated short columnar and acicular devitrite form a high-density microcrystalline composite phase material. At the same time as the crystallization in the glass in the first stage, because it is basically uniform crystallization inside, most of the slag particles remain in the glass state, which avoids the difficulty of poor fluidity and difficult sintering to eliminate pores during the high temperature treatment in the second stage. A very dense glass-ceramic material.

Claims (2)

1, a kind of prescription of devitrified glass is characterized in that its composition is divided into:

First kind slag class: its component is (weight %):

SiO ₂?44～60， Al ₂O ₃?3～10， CaO 10～21

MgO?3～7， ZnO?0.5～3.0， R ₂O(Na ₂O+K ₂O)3～7

FeO+Fe ₂O ₃?0.1～24.0 S 0.2～1.5

B ₂O ₃0～8, the reductive agent charcoal: 0～1, F ₂1～3

Cr ₂O ₃?0～1.5 Sb ₂O ₃ 0～1

Wherein RO (CaO+MgO+ZnO+FeO) should account for 25～38%,

The second class silt class: its component is (weight %)

SiO ₂?44～65 Al ₂O ₃?4～11 CaO 10～20

MgO 0～4 ZnO 0～2.5 B ₂O ₃?0～6

R ₂O(Na ₂O+K ₂O)10～18 FeO+Fe ₂O ₃ 0.1～2.0。

2, a kind of manufacturing process of devitrified glass is characterized by:

(1) integrally crystallization method

By the raw material of above-mentioned prescription, make sheet glass through fusing, calendering, die mould or cast technique, then in 550～620 ℃ of annealing, cool to room temperature gradually again; The sheet glass that obtains is raised to T with 150～350 ℃/hour speed _C1Near insulation 0.5～1 hour is not got rid of elder generation and be incubated for some time near glass softening point; Then be raised to and be higher than Tc with the speed that is not more than 300 ℃/hour ₂50～200 ℃ are incubated about 1.5 hours; Cooling cooling then promptly obtains crystallizing glass sheet material;

(2) sintering crystallization method:

The glass melt that will make by above-mentioned prescription flows in the water, and shrend becomes the disintegrating slag shape, and the glass disintegrating slag of getting granularity 1～15mm is put into and preserved to be had in the mould of ideal form, rises to a little less than T with the speed that is not higher than 400 ℃/hour _C1Near insulation 0.5～1 hour, do not get rid of and near glass softening point, be incubated for some time earlier, the temperature insulation that rises between 1000 ℃～1120 ℃ with the speed that is not higher than 300 ℃/hour then is about 1.5 hours, makes the softening and distortion of frit and adhere is in aggregates each other.