CN112811820A

CN112811820A - Microcrystalline glass

Info

Publication number: CN112811820A
Application number: CN202110069835.2A
Authority: CN
Inventors: 陈福; 续芯如; 冯建业; 闫亚琼
Original assignee: Qinhuangdao Glass Industry Research And Design Institute Co ltd
Current assignee: Qinhuangdao Glass Industry Research And Design Institute Co ltd
Priority date: 2019-02-25
Filing date: 2019-02-25
Publication date: 2021-05-18
Also published as: CN109704583A

Abstract

The invention discloses microcrystalline glass, which comprises the following main components in raw materials: SiO 2₂ 43％‑49.8％，Al₂O₃10.2％‑16％，CaO 5.5％‑9.9％，MgO 1.2％‑9.8％，Na₂O 3.1％‑6.5％，K₂O 2.3％‑7.7％，BaO4.2％‑8.8％，ZnO 4.5％‑10％，Sb₂O₃0.2-2%, nitrate 0.8-8%, P₂O₅ 0.3％‑1.8％,ZrO₂0.2-1.5 percent of fluoride, 0.1-0.7 percent of TiO₂0.7 to 3.5 percent. The microcrystalline glass is prepared from the tantalum-niobium tailings, so that blind mining of natural stones can be greatly reduced, the comprehensive utilization efficiency of the tantalum-niobium tailings is improved, and wastes are changed into valuables. The microcrystalline glass has few bubbles and high strength, and the finished product rate and the finished product quality are greatly improved; and the production utilizes idle tantalum-niobium tailings, so that resources are saved.

Description

Microcrystalline glass

The application is a divisional application of an invention patent application with the invention name of ' microcrystalline glass and a production method thereof ' and the application number of ' 201910137180.0 ', which is filed in the national intellectual property office of the people's republic of China on 25.2.2019.

Technical Field

The invention relates to the technical field of glass processing, in particular to microcrystalline glass.

Background

The microcrystalline glass is a glass which is prepared by taking natural inorganic materials as main raw materials and adopting a certain controlled nucleation and crystallization process and separating out a special microcrystalline phase from a glass liquid with special components, and the basic components are shown in table 1.

TABLE 1 basic composition of microcrystalline glass

Composition (I)	CaO	Al₂O₃	SiO₂	Sb₂O₃	ZnO+MgO	Na₂O
							Content/%	16-22	3-10	50-70	1-3	4-9	1-6

The microcrystalline glass has the triple advantages of glass, ceramic and natural stone, such as optical trafficability and surface optical performance of glass, mechanical and surface crystallization performance of ceramic, surface anisotropy and decoration of natural stone, and the like, and is superior to natural stone and ceramic in performance comparison shown in table 2.

TABLE 2 comparison of the properties of microcrystalline glass with ceramics and natural stone

As can be seen from table 2, the microcrystalline glass is superior to ceramics, natural marble and granite in dimensional stability (reflected by water absorption, since water absorption is related to thermal expansion coefficient, and materials with large water absorption are easy to deform, i.e. large thermal expansion coefficient and poor dimensional stability), frost resistance, durability of glossiness (i.e. weather resistance and durability of materials, represented by acid resistance and alkali resistance in table 2), strength (flexural strength and compressive strength), and the like. Therefore, the glass ceramics can be used as the decoration materials of inner and outer walls and floors of various buildings, and is an ideal material for a wash table board and a sanitary table board. The microcrystalline glass can be used as an outer wall of a building and high-grade decoration in a room, and can also be used as a mechanical structure, such as an insulating material in electronics and electricians, a bottom plate material of a large-scale integrated circuit, a microwave oven ovenware, a chemical and anticorrosive material, a mine wear-resistant material and the like, so that the microcrystalline glass has extremely wide application.

The existing production process of the microcrystalline glass mainly adopts a sintering method and is subjected to twice melting sintering. The sintering method comprises a melting water quenching sintering method and a direct sintering method, wherein the melting water quenching sintering method is used for melting glass, then water quenching is carried out on the glass to obtain small particles, then the particles are filled into a mould for nucleation and crystallization, and the specific procedures comprise: mixture preparation → glass melting → water quenching for preparing granules → molding → controlled crystallization → cold processing and the like; the process of the direct sintering method includes: mixture preparation → grinding and mixing → molding and sintering → cold working, etc.

For example, chinese patent application publication No. CN 1868946a discloses a waste residue glass ceramic and a method for preparing the same. The preparation method of the microcrystalline glass is a melt water quenching sintering method in a sintering method. The method has the advantages that the production energy consumption is low, the densification depth (namely the thickness of a formed microcrystalline layer) of the surface layer of the produced microcrystalline glass is about 2nm shallower than that of a direct sintering method, the thinner the microcrystalline layer is, the insufficient microcrystallization degree is shown, the poorer the performance of the obtained microcrystalline glass is, bubbles among glass particles are difficult to remove, the surface is rough, the porosity is high, deformation is easy to generate, the requirements on the high temperature resistance, the pressure resistance and the deformation resistance of a refractory mould used in subsequent forming are high, secondary processing and other processes need to be carried out on the surface of the microcrystalline glass, and the production energy consumption and the cost of the microcrystalline glass are further improved due to the secondary processing. The simultaneous use of magnesium oxide and calcium oxide is beneficial to the adjustment of the viscosity and the temperature performance of the glass, but the magnesium oxide is not used in the microcrystalline glass, and the high-content calcium oxide is used, so that the glass is brittle, and then the relatively high-price boron oxide is used for adjusting the melting temperature of the glass, so that the melting of the microcrystalline glass is promoted, and the production cost of the microcrystalline glass is increased.

The direct sintering method has the advantages that the crystal phase proportion depends on the integral crystallization capacity of the base glass when the microcrystalline glass is prepared, so that the crystallization process is difficult to control, the integral crystallization time is long, and the production efficiency and the yield are low.

At present, the rolling method can also be used for producing the microcrystalline glass, for example, the Chinese patent application with the publication number of CN 106746681A discloses the wear-resistant microcrystalline glass prepared by adopting industrial wastes. The microcrystalline glass is prepared by a rolling method, and the preparation process comprises the steps of preparing a mixed material → melting glass → rolling and forming → annealing → nucleating and crystallizing → cold processing and the like. The rolling method adopts the double rollers to rotate forwards to press glass for forming, the glass shrinks during forming, and simultaneously, the rough surface of the roller way causes unsmooth surface of the glass, so that polishing treatment is needed after forming, the process flow is increased, the yield is reduced, and the cost is increased. The microcrystalline glass comprises the raw materials of copper sulfate, nickel sulfide and magnesium diboride, and chromium sesquioxide is selected as a crystal nucleus agent for crystallization; wherein copper sulfate causes the glass to be colored blue, Cr₂O₃Middle Cr³⁺Belongs to heavy metal ions, can generate chromium pollution and poisoning phenomena, is unsafe and not environment-friendly, and is avoided in industry.

Disclosure of Invention

The invention aims to overcome the technical defects in the prior art, and provides bubble-free glass ceramics in a first aspect, which comprise the following main components in raw materials: SiO 2₂ 43％-49.8％，Al₂O₃ 10.2％-16％，CaO 5.5％-9.9％，MgO 1.2％-9.8％，Na₂O 3.1％-6.5％，K₂O 2.3％-7.7％，BaO 4.2％-8.8％，ZnO 4.5％-10％，Sb₂O₃0.2% -2%, nitrate (preferably NaNO)₃And/or KNO₃)0.8％-8％,P₂O₅ 0.3％-1.8％,ZrO₂0.2% -1.5%, fluoride (preferably CaF)₂And/or Na₂SiF₆)0.1％-0.7％,TiO₂ 0.7％-3.5％。

The main components of the raw materials comprise: SiO 2₂ 45％-47％，Al₂O₃ 11％-14％，CaO 6％-8％，MgO 3％-8％， Na₂O 4％-5％，K₂O 3％-6％，BaO 5％-7％，ZnO 5％-8％，Sb₂O₃0.5-1.5 percent of nitrate, 2-6 percent of nitrate and P₂O₅ 0.6％-1.5％,ZrO₂0.5-1.1 percent of fluoride, 0.2-0.5 percent of TiO₂1.2% -2.9%; preferably comprising: SiO 2₂ 46％， Al₂O₃ 12.5％，CaO 7％，MgO 5.5％，Na₂O 4.5％，K₂O 4.5％，BaO 6％，ZnO 6.5％，Sb₂O₃0.8%, nitrate 2.8%, P₂O₅ 0.8％,ZrO₂0.7 percent of fluoride, 0.4 percent of TiO₂ 2％。

The raw material comprises tantalum-niobium tailings (preferably Al)₂O₃Tantalum niobium tailings in higher content (e.g. more than 16%), the added mass of the tantalum niobium tailings is preferably 25% to 40%, more preferably 30% to 35%, most preferably 33% of the total mass of the raw material.

The product has less bubbles and high strength (for example, the compressive strength is not lower than 352MPa, and the flexural strength is not lower than 121 MPa).

The smooth finish is high (not less than 83.3), and polishing treatment is not needed after molding.

The water absorption rate is low and is not higher than 0.012 percent, so that the microcrystalline glass is not easy to deform.

The tantalum-niobium tailings are used as main raw materials and are produced by a float process, and the indexes of the tantalum-niobium tailings such as impact strength, compression strength and water absorption are superior to those of microcrystalline glass prepared by a sintering method.

The method for producing the microcrystalline glass sequentially comprises the steps of mixing raw materials, melting and clarifying molten glass, homogenizing and cooling the molten glass, forming the glass by adopting a float tin bath, nucleating the glass in the nucleating tin bath, crystallizing the glass in the crystallizing tin bath, annealing and the like.

The glass nucleation comprises one-time transition cooling and nucleation, and specifically comprises the following steps:

adjusting the temperature of the transition product obtained after tin bath forming to 600-660 ℃, and then entering a nucleation tin bath for nucleation, wherein the nucleation temperature is 580-640 ℃, and the nucleation time is 30min-3h, so as to obtain the primary transition product.

The glass crystallization comprises secondary transition temperature rise and crystallization, and specifically comprises the following steps:

and adjusting the temperature of the primary transition product to 740-950 ℃, and then entering a crystallization tin bath for crystallization, wherein the crystallization temperature is 730-940 ℃, and the crystallization time is 2-8.5h, so as to obtain a secondary transition product.

The glass forming specifically comprises the following steps:

the homogenized and cooled glass liquid enters a forming tin bath and is formed under the action of an edge roller to obtain a transition product with the thickness of 2-15mm, the inlet temperature of the forming tin bath is 1250-.

The method further comprises a pretreatment process of the tantalum-niobium tailings before mixing of the raw materials, wherein the pretreatment process of the tantalum-niobium tailings specifically comprises the following steps: the tantalum-niobium tailings are subjected to the working procedures of grading, scrubbing, magnetic separation, acid washing and the like in sequence to obtain Fe₂O₃The content of (a) is less than 0.01% (100ppm), the particle size is 0.1-1.5mm, and the water content is less than 5%.

The melting and clarifying of the molten glass and the homogenizing and cooling of the molten glass are specifically as follows: melting the mixed glass raw materials into glass liquid at 1600-1660 ℃, and keeping the temperature of the glass liquid at 1620-1670 ℃ until the glass liquid is uniformly mixed, wherein no bubbles are emitted; or

Optionally, the annealing specifically comprises: and continuously annealing the crystallized secondary transition product at 600-700 ℃ for 2-8h or to below 100 ℃ to obtain the glass ceramics.

Compared with the prior art, the microcrystalline glass prepared by the float process has better indexes such as impact strength, compression strength, water absorption (namely dimensional stability) and the like than the microcrystalline glass prepared by the current sintering method, and the physicochemical property and the decoration effect can reach the level of the microcrystalline glass prepared by the current sintering method, thereby being beneficial to application and popularization. Meanwhile, the tantalum-niobium tailings are adopted to prepare the microcrystalline glass for architectural decoration, so that blind exploitation of natural stones can be greatly reduced, the comprehensive utilization efficiency of the tantalum-niobium tailings is improved, and waste is changed into valuable.

In the preparation process of the microcrystalline glass, the total oxygen combustion technology is adopted to melt the glass raw materials into the molten glass, so that the melting and clarification processes of the molten glass can be accelerated, the generation of bubbles and stripe knots of the glass can be reduced, and the defects of the inside and the surface of the glass can be reduced.

In addition, the microcrystalline glass adopts a secondary forming process during forming, firstly, glass liquid is formed in a tin bath to form a uniform and flat plate-shaped glass transition product with certain thickness and width, the transition product is subjected to temperature adjustment outside the tin bath and then enters the tin bath again for nucleation and crystallization, the obtained microcrystalline glass has few bubbles and high strength, and the yield and the finished product quality are greatly improved; in addition, idle tantalum-niobium tailings are utilized in production, resources are saved, and K contained in the tantalum-niobium tailings₂O、Na₂O、Rb₂O、PbO、Li₂The eutectic effect is generated by the fusible oxides such as O, the melting temperature is reduced, the energy consumption in the production of the glass ceramics is reduced, and the resource environment is effectively protected.

Drawings

FIG. 1 is a longitudinal section of the structure of the special apparatus for producing glass ceramics according to the present invention;

FIG. 2 is a top view of the structure of the special apparatus for producing glass ceramics according to the present invention;

the glass melting furnace comprises a glass melting furnace 1, glass liquid 2, a cooling pool 3, a top space 4, a forming tin bath 5, a glass belt 6, a first transition roller table 7, rollers 8, a nucleating tin bath 9, a second transition roller table 10, a crystallization tin bath 11, a baffle 12, an annealing furnace 13, an oxy-fuel combustion spray gun 14, molten tin 15 and an edge roller 16.

Detailed Description

The Jiangxi Yichun tantalum-niobium tailings are tailing sand remained after tantalum-niobium is selected from lithium feldspar minerals containing rare metals of tantalum-niobium.

The ore dressing analysis of Al in tantalum-niobium tailing sample₂O₃Higher, therefore, can be introduced into the preparation of glass ceramics for architectural decoration to provide Al required for preparing the glass ceramics₂O₃(ii) a At the same time, a small part of Na can be introduced₂O is used for reducing the consumption of the calcined soda; p of introduction part₂O₅，ZrO₂Fluoride and TiO₂The crystal nucleating agent can be used as the crystal nucleating agent to reduce the dosage of the crystal nucleating agent, which is beneficial to reducing the production cost of glass, and the chemical components in the tantalum-niobium tailings are determined after mineral separation tests and are shown in Table 3.

TABLE 3 chemical composition of tantalum niobium tailings sample after beneficiation test

Through a great deal of experiments and repeated researches, the basic composition of the microcrystalline glass provided by the invention is finally selected to comprise SiO₂、 Al₂O₃、CaO、MgO、Na₂O、K₂O and ZnO, etc. The main components in the glass and the functions of the glass in the high-strength microcrystalline glass are as follows:

silicon dioxide SiO₂Is the main body of the glass forming skeleton, SiO in soda-lime-silicate glass₂Can reduce the thermal expansion coefficient of the glass and improve the thermal stability, chemical stability, softening temperature, hardness and mechanical strength of the glass.

Aluminum oxide Al₂O₃The oxide belongs to an intermediate oxide of glass, can reduce the crystallization tendency of the glass, improve the chemical stability, the thermal stability, the mechanical strength, the hardness and the refractive index of the glass, and reduce the erosion of the glass to refractory materials. Al in the glass ceramics of the invention₂O₃The content of Al in the common glass ceramics is 10.2 to 16 percent₂O₃The content of the alumina is not more than 10 percent because the invention finds that the microcrystalline glass can have AlO when the content of the alumina is high₄]And [ AlO ]₆]The two structures have low requirements on environmental parameters when the glass product is directly applied and deeply processed, are beneficial to chemical toughening of glass and are beneficial to large-area popularization and application of products.

Sodium oxide Na₂O is an oxide of the external body of the glass network, can reduce the viscosity of the glass, enables the glass to be easily melted, and is a good fluxing agent for the glass. Na (Na)₂O increases the coefficient of thermal expansion of the glass, and decreases the thermal, chemical and mechanical strength of the glass.

Potassium oxide K₂O is also an exo-oxide of the glass network, its role in glass and Na₂O is similar. Potassium ion (K)⁺) Radius ratio of sodium ion (Na)⁺) Viscosity of the large, potassium glassLarger than sodium glass, can reduce devitrification tendency of glass, increase transparency and luster of glass, and can be mixed with Na₂O produces a mixed alkali effect, which is beneficial to the melting of glass.

Calcium oxide CaO is a divalent glass network exo-oxide. Its main function is as a stabilizer, i.e. to increase the chemical stability and mechanical strength of the glass. When the content is high, the glass tends to crystallize.

Magnesium oxide MgO is an exo-network oxide in soda-lime-silicate glasses. The glass has 10% or less MgO to replace partial CaO, so that the hardening speed of the glass is reduced, the crystallization tendency of the glass is reduced, and the chemical stability and the mechanical strength of the glass are improved.

The barium oxide BaO is also an external oxide of a glass network, can increase the refractive index, the density gloss and the chemical stability of the glass, can also prolong the material property of the glass, and can also accelerate the melting and crystallization of the glass by a small amount of barium oxide.

The zinc oxide ZnO is a glass intermediate oxide, so that the glass structure is more compact, the thermal expansion coefficient of the glass can be reduced, the thermal stability and the chemical stability of the glass are improved, the refractive index of the glass is increased, and the melting, phase separation and crystallization of the glass at high temperature can be accelerated.

Phosphorus pentoxide P₂O₅Is a glass forming oxide which is tetrahedral to phosphorus oxygen [ PO ]₄]The phosphate glass forms a structural network, improves the glass dispersion coefficient and the capability of passing ultraviolet rays, and can be used as a crystal nucleus agent in the process of preparing the microcrystalline glass.

Zirconium dioxide ZrO₂The glass is an intermediate oxide, can improve the viscosity, hardness, elasticity, refractive index and chemical stability of glass, reduces the thermal expansion coefficient of the glass, and can be used as a nucleating agent of microcrystalline glass.

Fluoride is a fluxing agent and an opacifier commonly used in the glass industry, and can also be used as a crystal nucleus agent of microcrystalline glass, and CaF is mainly selected₂And Na₂SiF₆。

Titanium oxide TiO₂Is an intermediate oxide, and can improve the refractive index and chemical stability of the glass, and increaseThe glass crystal nucleating agent can absorb X rays and ultraviolet rays and can be used as a crystal nucleating agent of aluminosilicate microcrystalline glass.

During the glass melting process, a large amount of gas can be separated out due to the decomposition of each component of the batch, the volatilization of volatile components and the like. Until the glass forming process is finished, a small part of gas can not completely escape from the molten glass and remains in the molten glass in the form of bubbles. Therefore, in order to obtain pure, uniform and high-quality molten glass, antimony trioxide (Sb) is added into the glass batch₂O₃) And nitrates (typically sodium and potassium nitrates) as fining agents to facilitate the removal of air bubbles from the molten glass. The present invention selects Sb as the sulfate fining agent₂O₃Nitrate is used as a clarifying agent, SO that secondary sulfate bubbles are not generated, and pollutants SO are not generated in flue gas₂The method is favorable for reducing the load of flue gas desulfurization and denitration and reducing the production cost of the microcrystalline glass. Simultaneously adding nano titanium dioxide (TiO) into the glass raw material₂) Phosphorus pentoxide (P)₂O₅) Fluoride and nano zirconium dioxide (ZrO)₂) As a crystal nucleus agent, the glass nucleating and crystallizing process is accelerated, the generation and growth of microcrystals are accelerated, namely the process of converting a glass body into crystals is accelerated, and surrounding tiny particles can be gathered together, so that the discharge of bubbles in molten glass is promoted.

The invention adopts tantalum-niobium tailings as main raw materials, and the indexes of the microcrystalline glass produced by the float process, such as impact strength, compression strength and the like, are superior to those of the microcrystalline glass obtained by a sintering method. However, the microcrystalline glass of the present invention contains Al in its glass component₂O₃The content is high, and the float production has two technical problems: firstly, the glass melting temperature is high, and clarification and homogenization are difficult; and secondly, the microcrystallization is difficult to control because the temperature difference between the melting temperature and the forming temperature is large when the float process is adopted to produce the glass ceramics, and meanwhile, the nucleation temperature and the crystallization temperature are different, so that the control in a tin bath is difficult. As for the first problem, the invention adopts the oxy-fuel combustion technology, so that the viscosity of the molten glass is reduced, the problem of difficult clarification and homogenization is solved, and air bubbles and ash bubbles in the molten glass can be reducedAnd streaks. Aiming at the second problem, P is added into the tantalum-niobium tailings₂O₅，ZrO₂Fluoride and TiO₂And the glass liquid is subjected to tin bath forming, leaves the tin bath after forming, enters the tin bath again after the temperature is adjusted by a transition roller table, and is subjected to nucleation and crystallization, so that the microcrystallization process is controllable, the generation of defects is prevented, the stability of the crystallization process is ensured, the continuous production is realized, the purposes of high efficiency and low cost are achieved, and the high-quality microcrystalline glass for architectural decoration is obtained.

The invention uses the float process to produce the microcrystalline glass, but is not similar to the float process to produce the ordinary glass. The float process of producing common glass includes feeding molten glass liquid into tin bath for forming, cooling in transition roller table and annealing in annealing kiln.

The invention uses float method to produce glass ceramics, which makes the melted glass flow into the molding tin bath to be molded, then the glass flow enters into the nucleation tin bath and the crystallization tin bath to be nucleated and crystallized respectively, and then the glass flow enters into the annealing kiln to be annealed after being cooled gradually in the crystallization tin bath, so as to eliminate the stress of the glass. During annealing, the glass ribbon is heated, soaked, heat preserved, slowly cooled, fast cooled, etc. according to certain temperature curve, so that the internal stress value produced during forming and cooling is reduced to reach the standard meeting the requirement of cutting and quality.

The glass ceramics of the present invention is prepared by the float process, and therefore, can be called as float glass ceramics, which is prepared by the steps of crushing, blending, melting, float forming, crystallizing, annealing, etc. of natural inorganic materials. The float glass ceramics has the excellent characteristics of glass ceramics obtained by a sintering method: such as no radiation, no water absorption, no corrosion, no oxidation, no fading, no color difference, no deformation, high strength, high glossiness and the like; in addition, the method has the advantages of no bubbles, natural and beautiful patterns, better physical and chemical properties, ultra-thin and ultra-wide product specification, no pores, easy cleaning, high yield, low cost and the like. The float glass ceramics can be used as high-grade building decorative materials, has very good flatness, surface gloss and excellent physical and chemical properties, and can replace natural granite to be used for decorating inner and outer walls, floors and table tops of various buildings. The popularization and application of the float glass ceramics can form a new economic growth point, and the advantages of high performance quality, low production cost and large-scale production are brought to the world. In addition, industrial waste residues can be used as main raw materials (such as tantalum-niobium tailings, gold tailings and the like) in the production of the float glass ceramics, which belongs to an environment-friendly project and is a first-choice new product for improving economic benefits by adjusting the structure of a float glass enterprise.

The method adopts the tantalum-niobium tailings as the raw material to prepare the float glass ceramics, the prepared glass has stable performance and wide application, is beneficial to the application and popularization of the glass ceramics, can accelerate the comprehensive utilization of the tantalum-niobium tailings, and reduces the pollution to the environment.

The present invention will be described more specifically and further illustrated with reference to specific examples, which are by no means intended to limit the scope of the present invention.

The process of heating the batch at high temperature to form uniform glass liquid which is bubble-free and meets the forming requirement is called melting of glass. The glass melting process is an important link in glass production. Many defects in glass (e.g., bubbles, stones, striae, etc.) are caused by non-uniformities in the molten glass during the melting process. The yield, quality, qualification rate, production cost, fuel consumption, the service life of a tank furnace for melting and the like of the glass are all closely related to the melting of the glass. Therefore, the reasonable glass melting is an important guarantee that the whole production process can be smoothly carried out and high-quality glass products can be efficiently produced.

The invention determines that tantalum-niobium tailings are used for producing microcrystalline glass for architectural decoration through a large amount of researches, and the microcrystalline glass comprises the following raw materials in percentage by mass: SiO 2₂ 43％-49.8％，Al₂O₃ 10.2％-16％，CaO 5.5％-9.9％，MgO 1.2％-9.8％，Na₂O 3.1％-6.5％，K₂O 2.3％-7.7％，BaO 4.2％-8.8％，ZnO 4.5％-10％，Sb₂O₃0.2-2%, nitrate 0.8-8%, P₂O₅ 0.3％-1.8％,ZrO₂0.2% -1.5%, fluoride 0.1-0.7％,TiO₂0.7% -3.5%; wherein P is₂O₅，ZrO₂Fluoride and TiO₂As a composite nucleating agent;

preferably:

SiO₂ 45％-47％，Al₂O₃ 11％-14％，CaO 6％-8％，MgO 3％-8％，Na₂O 4％-5％，K₂O 3％-6％， BaO 5％-7％，ZnO 5％-8％，Sb₂O₃0.5-1.5 percent of nitrate, 2-6 percent of nitrate and P₂O₅ 0.6％-1.5％,ZrO₂0.5-1.1 percent of fluoride, 0.2-0.5 percent of TiO₂ 1.2％-2.9％。

More preferably:

SiO₂ 46％，Al₂O₃ 12.5％，CaO 7％，MgO 5.5％，Na₂O 4.5％，K₂O 4.5％，BaO 6％，ZnO 6.5％，Sb₂O₃0.8%, nitrate 2.8%, P₂O₅ 0.8％,ZrO₂0.7 percent of fluoride, 0.4 percent of TiO₂ 2％。

In the raw materials for producing the glass ceramics, the optimum introduced mass percentage content of the tantalum-niobium tailings is 25-40%, preferably 30-35%, and more preferably 33% of the total mass of the glass raw materials. The introduction proportion can utilize tantalum-niobium tailings to the maximum extent under the condition of ensuring the stable composition of the microcrystalline glass, and simultaneously, partial trace elements such as Li contained in the tailings₂O、Rb₂O, PbO, NiO and the like, and is also beneficial to melting and refining the glass.

The invention also provides special equipment for producing the microcrystalline glass, which has a structure shown in figures 1 and 2 and comprises a glass melting furnace 1, a cooling pool 3, a forming tin bath 5, a first transition roller table 7, a nucleating tin bath 9, a second transition roller table 10, a crystallization tin bath 11 and an annealing furnace 13 which are connected in sequence. Wherein:

the glass melting furnace 1 is used for melting the mixed glass raw materials into molten glass 2 and removing visible bubbles in the molten glass. The process of removing visible bubbles is called fining of the molten glass, i.e. both melting of the glass raw material and fining of the molten glass are carried out in the glass melting furnace 1.

The cooling tank 3 is used for homogenizing and cooling the clarified molten glass and adjusting the viscosity of the molten glass, namely: uniformly mixing the molten glass raw materials, adjusting the viscosity of the molten glass, and cooling to the forming temperature to ensure the subsequent forming of the molten glass;

the forming tin bath 5 is used for drawing the molten and uniformly mixed glass liquid into a glass product with a fixed geometric shape, the forming tin bath 5 comprises 6-12 pairs of edge rollers 16 which are arranged in pairs at two sides, the glass liquid 2 floats on the molten tin liquid 15 after entering the forming tin bath 5, and the glass liquid 2 is drawn into a glass ribbon 6 under the tension of the edge rollers 16 which are arranged in pairs at two sides of the forming tin bath 5, so that the forming is completed.

The first transition roller table 7 is used for adjusting the temperature of the formed glass ribbon 6 to 600-660 ℃, and then conveying the glass ribbon to the tin nucleating tank 9; the rollers 8 in the first transition roller table 7 are made of quartz ceramic.

The nucleating tin bath 9 is filled with molten tin liquid 15, the glass ribbon 6 floats on the surface of the molten tin liquid 15 after entering, and the molten tin liquid 15 regulates the temperature of the glass ribbon 6 to 580-640 ℃ for nucleating; the nucleated tin bath 9 differs from the profiled tin bath in that no edge rollers 16 are provided on both sides.

The second transition roller table 10 is used for adjusting the temperature of the nucleated glass ribbon 6 to 740 and 950 ℃, and then conveying the nucleated glass ribbon to the crystallization tin bath 11; the rollers 8 in the second transition roller table 10 are made of quartz ceramic.

The crystallization tin bath 11 is filled with molten tin liquid 15, the glass ribbon 6 floats on the surface of the molten tin liquid 15 after entering, and the molten tin liquid 15 adjusts the temperature of the glass ribbon 6 to 730-940 ℃ for crystallization; the crystallized tin bath 11 differs from the formed tin bath in that no edge rollers 16 are provided on both sides.

Filling nitrogen and hydrogen in the upper spaces 4 of the molding tin bath, the nucleation tin bath and the crystallization tin bath to prevent the tin liquid from being oxidized; the nucleation and crystallization of the glass automatically occur when the glass is adjusted to a certain temperature range, the crystal nucleating agent is uniformly mixed with other raw materials when the glass raw materials are added, and the mixture is uniformly distributed in molten glass liquid again at high temperature when the glass raw materials are melted, and after the temperature of the nucleation and crystallization is reached, the crystal nucleating agent promotes the formation of crystal nuclei in the glass and enables crystals to grow up to form the microcrystalline glass.

The annealing furnace 13 is for continuously reducing the temperature of the glass ribbon 6 having a certain thickness after the forming to below 100 ℃ in order to eliminate the stress in the glass ribbon; the annealing kiln 13 is separated from the crystallized tin bath 11 by a baffle curtain 12.

The invention also provides a production method of the microcrystalline glass, which comprises the steps of pretreatment of tantalum-niobium tailings, mixing of raw materials, melting and clarification of glass liquid, homogenization of the glass liquid, tin bath molding, primary transition cooling and nucleation, secondary transition heating and crystallization, annealing and the like; the steps are carried out in the special equipment for producing the microcrystalline glass, and specifically comprise the following steps:

1) and (3) pretreating tantalum-niobium tailings:

sequentially carrying out the working procedures of grading, scrubbing, magnetic separation, acid washing and the like on the tantalum-niobium tailings to obtain a tantalum-niobium tailings sample suitable for producing microcrystalline glass, wherein Fe in the tantalum-niobium tailings sample₂O₃Has a content of less than 0.01% (100ppm), a particle diameter of 0.1-1.5mm, and a water content of less than 5%.

2) And mixing the raw materials:

after detecting the chemical composition in the tantalum-niobium tailing sample, calculating to obtain SiO₂、Al₂O₃、CaO、MgO、Na₂O、 K₂O、B₂O₃、ZnO、Li₂Mixing one or more of O and MnO with the tantalum-niobium tailings sample obtained in the step 1) to obtain a mixture containing SiO₂43％-49.8％，Al₂O₃ 10.2％-16％，CaO 5.5％-9.9％，MgO 1.2％-9.8％，Na₂O 3.1％-6.5％， K₂O 2.3％-7.7％，BaO 4.2％-8.8％，ZnO 4.5％-10％，Sb₂O₃0.2-2%, nitrate 0.8-8%, P₂O₅ 0.3％-1.8％,ZrO₂0.2-1.5 percent of fluoride, 0.1-0.7 percent of TiO₂0.7 to 3.5 percent of glass raw material; in general industrial production, SiO₂From silica sand, Al₂O₃Feldspar from feldspar, CaO from limestone, MgO from magnesite, and Na₂O is derived from soda ash and K₂O is derived from potassium carbonate.

SiO is preferably contained in the glass raw material₂ 45％-47％，Al₂O₃ 11％-14％，CaO 6％-8％，MgO 3％-8％，Na₂O 4％-5％， K₂O 3％-6％，BaO 5％-7％，ZnO 5％-8％，Sb₂O₃0.5-1.5 percent of nitrate, 2-6 percent of nitrate and P₂O₅ 0.6％-1.5％,ZrO₂0.5-1.1 percent of fluoride, 0.2-0.5 percent of TiO₂1.2% -2.9%; more preferably SiO₂ 46％，Al₂O₃ 12.5％，CaO 7％，MgO 5.5％，Na₂O 4.5％，K₂O 4.5％，BaO 6％，ZnO 6.5％，Sb₂O₃0.8%, nitrate 2.8%, P₂O₅ 0.8％,ZrO₂0.7 percent of fluoride, 0.4 percent of TiO₂ 2％。

3) Melting and clarifying the molten glass:

melting the mixed glass raw materials in the step 2) at the temperature of 1600-1660 ℃ to form molten glass, which generally needs about 24 hours; when the obtained molten glass does not bubble out any more (about 12-25h is generally needed to carry out sufficient clarification), the clarification is finished;

4) homogenizing and cooling the molten glass:

the temperature of the clarified glass liquid is kept at 1620 ℃ and 1670 ℃ until all parts of the glass liquid are uniform in chemical composition (generally requiring 7-16h), and the homogenization is finished, wherein the homogenization is to eliminate stripes and inhomogeneities in the glass liquid; cooling the glass liquid to 1350-;

5) and forming a molten tin bath:

and 4) feeding the homogenized and cooled glass liquid into a tin bath for molding, so that the glass is molded uniformly and flatly to form a plate-shaped glass transition product with certain thickness and width, wherein the thickness is 2-15mm, the width is generally equal to the width of the tin bath, the inlet temperature of the tin bath is 1250-.

6) First transition cooling and nucleation:

and (3) the formed transition product enters a first transition roller table, the temperature is adjusted to be 600-.

7) Secondary transition temperature rise and crystallization:

and the nucleated primary transition product enters a second transition roller table, the temperature is adjusted to 740-940 ℃ and then enters a tin bath again for crystallization, the crystallization temperature is 730-940 ℃, and the crystallization time is 2-8.5h, so that a secondary transition product is obtained.

8) And annealing:

annealing the crystallized secondary transition product at 600-700 ℃ for 2-8h or below 100 ℃ in a continuous mode to eliminate the stress of the glass and obtain the glass-ceramic.

The microcrystalline glass of the embodiment 1 to the embodiment 7 is prepared by utilizing the special equipment for producing the microcrystalline glass and the glass raw material containing the tantalum-niobium tailings according to the method for producing the microcrystalline glass. The parameters and the raw material composition for producing the crystallized glasses of examples 1 to 7 are shown in table 4.

Table 4 raw material composition and production parameters of microcrystalline glass of example 1 to example 7

Experiment:

the bending strength of the glasses obtained in examples 1 to 7 and comparative examples 1 to 4 was measured, and a glass sample was cut, ground, polished, and formed into a 80X 10mm long strip by a three-point bending method using a DKZ-5000 type electric bending tester. The results of the performance tests are shown in Table 5.

Therefore, compared with the microcrystalline glass obtained by the sintering method, the microcrystalline glass has higher strength, is suitable for being used as a building decoration material requiring high strength, has good machining performance and can be widely applied.

TABLE 5 results of performance test of glasses of examples 1 to 7 and comparative examples 1 to 4

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be regarded as the content of the present invention.

Claims

1. The microcrystalline glass is characterized in that the raw materials comprise the following main components: SiO 2₂ 43％-49.8％，Al₂O₃10.2％-16％，CaO 5.5％-9.9％，MgO 1.2％-9.8％，Na₂O 3.1％-6.5％，K₂O 2.3％-7.7％，BaO 4.2％-8.8％，ZnO 4.5％-10％，Sb₂O₃0.2% -2%, nitrate (preferably NaNO)₃And/or KNO₃)0.8％-8％,P₂O₅ 0.3％-1.8％,ZrO₂0.2% -1.5%, fluoride (preferably CaF)₂And/or Na₂SiF₆)0.1％-0.7％,TiO₂ 0.7％-3.5％。

2. The microcrystalline glass according to claim 1, wherein the main components in the raw materials comprise: SiO 2₂45％-47％，Al₂O₃ 11％-14％，CaO 6％-8％，MgO 3％-8％，Na₂O 4％-5％，K₂O 3％-6％，BaO 5％-7％，ZnO 5％-8％，Sb₂O₃0.5-1.5 percent of nitrate, 2-6 percent of nitrate and P₂O₅ 0.6％-1.5％,ZrO₂0.5-1.1 percent of fluoride, 0.2-0.5 percent of TiO₂1.2% -2.9%; preferably comprising: SiO 2₂ 46％，Al₂O₃ 12.5％，CaO 7％，MgO 5.5％，Na₂O 4.5％，K₂O 4.5％，BaO 6％，ZnO 6.5％，Sb₂O₃0.8%, nitrate 2.8%, P₂O₅0.8％,ZrO₂0.7 percent of fluoride, 0.4 percent of TiO₂ 2％。

3. The method according to claim 1 or 2The microcrystalline glass is characterized in that the raw material comprises tantalum-niobium tailings (preferably Al)₂O₃Tantalum niobium tailings in higher content (e.g., more than 16%), the added mass of the tantalum niobium tailings is preferably 25% to 40%, more preferably 30% to 35%, and most preferably 33% of the total mass of the raw material.

4. The glass-ceramic according to any one of claims 1 to 3, characterized in that it has a low bubble content and a high strength (for example, a compressive strength of 352MPa or more and a flexural strength of 121MPa or more).

5. The glass-ceramic according to any one of claims 1 to 4, characterized in that it has a high degree of finish (not less than 83.3).

6. The glass-ceramic according to any one of claims 1 to 5, characterized in that it has a low water absorption of not more than 0.012%.

7. The glass-ceramic according to any one of claims 1 to 6, wherein the tantalum-niobium tailings are used as main raw materials and produced by a float process, and the indexes such as impact strength, compression strength and water absorption rate of the glass-ceramic are superior to those of the glass-ceramic prepared by a sintering method.

8. The microcrystalline glass according to claim 7, wherein the method for producing the microcrystalline glass comprises the steps of mixing raw materials, melting and clarifying molten glass, homogenizing and cooling the molten glass, forming the glass by using a float tin bath, nucleating the glass in the nucleating tin bath, crystallizing the glass in the crystallizing tin bath, and annealing.

9. The glass-ceramic according to claim 8, wherein the glass nucleation comprises a primary transition cooling and nucleation, specifically:

10. A glass-ceramic according to claim 7 or 8, wherein the glass crystallization comprises a second transition heating and crystallization, specifically: