CN1257050A

CN1257050A - Novel boron-containing raw material for glass, glaze or enamel glaze

Info

Publication number: CN1257050A
Application number: CN 99123790
Authority: CN
Inventors: 张喜凤
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-11-23
Filing date: 1999-11-23
Publication date: 2000-06-21

Abstract

The present invention uses calcium borate xCaO.yB2O3.zH2O as raw material, has no need of firstly making it into glass marble or frit, and adopts direct heating process to prepare such products as glass, glass fibre,ceramic glaze, coloured glaze and enamel, etc.. As compared with other borate, the calcium borate possesses the effects of reducing heating (melting, sintering and firing) temperature, saving fuel, reducing volatilizing rate of B2O3, increasing strength, raising finished product rate and yield and prolonging furnace and kiln life, but also can be substituted for lead glaze, so that its application range is extensive, it can resist oxidation for a long period, does not change colour, and its hardness and thermal stability are raised.

Description

Boron-containing raw material for glass, glaze or enamel glaze

The invention relates to a method for directly preparing an amorphous product by using chemicals in the form of calcium borate xCaO.yB 2O 3. zH2O (x, y is 1, 2, 3 … 20; z is 0, 1, 2, 3 … 20) or a mixture thereof as raw materials, so that the preparation process is simplified, and the performance is obviously improved.

The present invention belongs to the application of non-metal compound calcium borate in glass, glaze or enamel glaze.

The boron-containing raw material is borax Na which is often used in glass, glass fiber, enamel glaze, ceramic glaze, colored glaze and enamel₂B₄O₇·nH₂O (n ═ 0, 5, 10), boronic acid (H)₃BO₃). B, in the high-temperature melting process of the boric acid and the borax, the temperature is between 100 and 900 DEG C₂O₃The volatilization rate is as high as 6-8%, and the calcium borate is almost not volatilized below 1200 ℃. Boric acid and borax are easy to dissolve in water, are not convenient to be directly used as raw glaze powder, and are required to be melted into frits in advance, ground, mixed with other raw materials and melted again to obtain finished products.

CaO is often introduced into the non-metallic material industry by cheap limestone, calcite and dolomite. But at the temperature of between 70 and 1000 ℃, CaO melting point 2580 ℃ and CO₂Bubbles and pinholes tend to form in the formation of amorphous articles.

Fine ceramics made ofThe articles are often glazed with lead-containing compounds. Lead oxide has a melting point of 882 ℃ and is suitable for low-temperature firing, but it is necessarily required to be carried out in an oxidizing atmosphere. The lead compounds have high specific gravity and are easy to precipitate. For weathered kaolin and clay ore in south China containing many organic matters, the red Fe is used₂O₃The cyan FeO is required to adopt a high-temperature strong reducing atmosphere, and the use of lead compounds is inconvenient. Calcium borate is available in both oxidizing and reducing atmospheres. Lead oxide begins to volatilize at a temperature above 750 ℃ and is toxic to the environment. At room temperature, the lead-containing glaze is easy to dissolve in acidIn sexual media, people inevitably come into contact with the composition. The frit is also prepared in advance in order to reduce the poisoning of the lead compound.

So that the preparation of amorphous state from borax, boric acid, limestone and lead compound is not the best way. The calcium borate is usedas the raw material, the property is unique, the process is simple and convenient, the raw material and the fuel are saved, and the effect of the finished product is obviously improved.

B₂O₃CaO eutectic 870 ℃, e.g. containing alkali compounds B₂O₃～CaO～R₂The eutectic point of O is 760 ℃, the glass is prepared by solely taking calcium borate as a raw material, and the thermal expansion coefficient is 3-5 multiplied by 10^-7and/K. Introduction of B in the form of calcium borate₂O₃CaO than B alone₂O₃The potential for reaction with the CaO form is much lower. The borax is also reacted with other solid raw materials at the temperature of more than 1000 ℃, and the temperature is 1200-1350 ℃ when the fritted glaze is prepared.

The calcium borate synthesized by the invention can be made into an amorphous state, and an amorphous product is made by introducing an amorphous raw material, so that the potential energy is low. The crystalline boron-containing raw materials of boric acid, borax, ascharite and even natural colemanite are all in a crystal form, so that the potential energy is high inevitably in the process of generating an amorphous state, and more heat energy is consumed. Compared with the melting temperature of the two, the difference of the sintering temperature and the sintering temperature is 15-110 ℃, the difference of the sintering temperature and the sintering temperature is 10-84 ℃, the fuel can be saved by 12-42%, and the furnace life is correspondingly prolonged.

Calcium borate is slightly soluble in water, and the solubility in water is 0.2-0.24%, so the calcium borate is suitable to be directly used as a raw material, mixed with other non-metallic compounds, natural products and industrial wastes, and prepared into the calcium borate by one-time heating (melting, sintering and firing)Theproduct is heated for more than two times and is quenched to room temperature to become heated and quenched for one time, namely the most precious B₂O₃The volatilization is reduced by more than half. The fuel is also greatly reduced, and the secondary grinding powder is changed into primary grinding powder.

The calcium borate is prepared into a product containing CaO and B according to different purposes₂O₃Chemicals in different proportions or mixtures thereof. B is₂O₃The content of the superfine powder is 28-67%, and the superfine powder can be crystal or amorphous and can be less than 0.5 mu.

The calcium borate is a strong fluxing agent and has better fluxing effect than other boron-containing raw materials. If the charge level in the glass kiln is flat at more than 1500 ℃, the foam diameter is balanced, the liquid level is bright, the high-temperature liquid phase line moves forward, and the melting state is obviously improved. So that the formed glass phase is uniform, no crystallization occurs and the strength of the finished product is high. Such as the strength of the glass product is doubled. For example, the pressure resistance of a 5000 ml narrow-mouth bottle is 0.3MPa without cracks. The 1000 ml beaker is quenched three times from room temperature to 210 ℃ without cracking. The strength of the glass fiber is increased by 9.2-18.6%.

The invention aims to use calcium borate as a raw material for amorphous substances such as glass, glaze, enamel and the like.

The preparation process is simple and convenient and is traditional: the chemical components containing boron and calcium in the original formula are changed into calcium borate when being introduced into the raw materials, and lead compounds are PbO and B₂O₃The ratio of the amount of the compound (A) to the amount of the compound (B) is 1: 0.5 to 1.5mol (preferably 0.8 to 1.2 mol). The raw materials are changed, the process is changed from secondary heating to primary heating, the heating temperature is reduced, and the equipment, facilities, detection means, transparent glaze and non-transparent glaze, colored glaze and non-colored glaze, ground glaze and overglaze and glass varieties are all suitable and are not changed.

The alkali-free glass fiber is prepared by directly using colemanite in the tank furnace method. The borohard calcium stone natural mineral powder contains 0.3-5% of SO₃The arsenic trioxide and other impurities are contained, and the total amount of the impurities reaches 9-13%. Compared with the calcium borate and the colemanite, the melting temperature is 10-50% lower, the wire drawing temperature is reduced by 7-20 ℃, the volatilization rate is below 1600 ℃, the calcium borate is 5.7%, the colemanite is 6.5%, the ascharite is 8.9%, the boric acid is 14%, the tensile strength is improved by 9-15%, and the product yield is improved by 6-12%. Because of no sulfide, the temperature dropsLow cost, and can prolong the service life of the kiln.

Compared with the boron magnesium ore, the calcium borate has the characteristics of low heating (melting, sintering and sintering) temperature of 10-60 ℃, widened forming temperature, difficult crystallization and easy forming. Therefore, the amorphous product has limited MgO content in the formula, and is not suitable for being prepared more, and the finished product prepared from the boron-magnesium ore as the raw material has poor performance. For example, in the glass fiber industry, the difference between the tensile strength of glass fiber containing 4.5% of MgO and the tensile strength of glass fiber containing 2.5% of MgO is 10%, the difference between the fuel consumption is 16%, the glass fiber containing not less than 2.6% of MgO must be melted at about 1600 ℃ to prepareglass balls, and then the glass balls are melted at 1450-1350 ℃ to form drawn wires, so that the fiber quality is poor, and the price is much lower.

Reference is made to the following references in connection with the present text:

1. chinese patent: 88103561.0 method for preparing calcium borate

2. Chinese patent: 99110544.4 method for preparing calcium borate from boron ore

Example 1 glass fiber

Taking alkali-free glass fiber as an example, raw materials are melted in a water chestnut kiln and a transverse flame kiln at the temperature of 1590-1610 ℃ in China, and the raw materials are pyrophyllite, quartz sand, ascharite, boric acid and limestone, and are proportioned as follows:

melting, cooling to obtain glass balls, inspecting the indexes such as secondary bubbling temperature and fringe disappearance distance to remove waste balls containing more bubbles and impurities, melting at 1350-1450 deg.C, controlling the bushing temperature at 1160-1240 deg.C, and increasing the tensile strength at 270Kg/mm²。

The method comprises the following steps: pyrophyllite, quartz sand, calcium borate, no or little boron-magnesium ore (MgO is controlled to be 0.5-2.6 percent), wollastonite, the melting temperature is 1490-. The process of manufacturing glass balls is cancelled, and the glass fiber is directly drawn into the glass fiber with the tensile strength of 300-320 Kg/mm²The fuel is saved by 18-42%, and the yield is increased by 9.8% -12.6%.

Example 2 tank furnace method glass fiber

Such as colemanite (containing SO) for alkali-free glass fiber raw material in tank furnace₃0.3-5% and 9-13% of impurities in total), the calcium borate can be used instead, the melting temperature is reduced by 15-50 ℃, and can reach 1460-1540 ℃. The drawing temperature is reduced by 8-23 ℃ and can reach 1210-1160 ℃. The strength of the fiber is increased by 9-15% and can reach 320-350 Kg/mm². The yield is increased by 6-12%, and the ingredient MgO is 0.5-2.6%.

Example 3 glass article as a typical borosilicate glass

The first five raw materials are ground to 200 meshes and melted at 1540-1460 ℃, and the temperature is reduced by 30-60 ℃. After the glass product is prepared, the diameter is less than 300mm, the pressure resistance is 0.3MPa, and the application pressure is 0.196 MPa.

Example 4 ceramic glaze

For example, glaze materials in porcelain or stoneware, fine porcelain and industrial porcelain are taken as examples: the mole fractions were as follows:

note: b is₂O₃And (3) ingredient calculation: 0.53+0.33(PbO) ═ 0.86, to reduce volatilization, so 0.8 was used as the ingredient.

The original formula is prepared from borax.

Grinding, mixing, spraying or coating on the blank to ensure that the fired product is brighter, uniform and smooth, has no crack when rapidly cooled and rapidly heated (20-220 ℃) for three times, has the bending strength of 20MPa and the Mohs hardness of 7.6. Now it has become a porcelain with lead-free glaze.

Example 5 ceramic glaze

The frit is prepared by adding lead compound with the concentration of 6-31.4% of boraxor boric acid into the original glaze of the inner wall brick and the floor tile. The scheme is changed into that calcium borate, feldspar, powder and pulp are milled and mixed to directly prepare raw glaze, the raw glaze is directly sprayed to form overglaze, and the contained PbO and calcium borate are replaced by equimolar components.

The firing temperature is changed from original 1060 ℃ to 950-1050 ℃.

The finished product meets the GB/T4100-94 standard: the whiteness is 89, the water absorption is 18, and the quenching and rapid heating (no crack at 20-220 ℃ and the bending strength is 19 MPa).

Example 6 enamel frit

The base glaze of the original cast iron, steel and enamel glaze comprises the following components: the mole fractions were as follows:

b must be considered in the raw ingredients₂O₃The volatility is 4.0 percent, and the invention is not considered any more. CoO + NiO0.06, MnO of raw material₂0.08 was still introduced in the original conventional manner from a pre-made frit to a green powder. HCL corrosion resistance of product is 0.6g/m²D, NaOH corrosion resistance 3.5g/m²D, mechanical impact resistance 280X 10^-3J, the temperature difference is rapidly changed, and the temperature difference reaches or exceeds the standard issued by the Ministry of chemical industry.

Claims

1. This patent uses xCaO yB₂O₃·zH₂The amorphous (or noncrystal-containing) product is prepared by directly heating (melting, sintering and sintering) crystalline or noncrystal calcium borate formed by O (x, y is 1, 2, 3 … 20; z is 0, 1, 2, 3 … 20) as a raw material, and has a series of unique effects with other borate by two times of heating: energy saving, simplified process, increased strength of the finished product and replacement of lead compound.

2. The calcium borate of claim 1 wherein 28-67% B is₂O₃And 42-67% of crystals, and also comprises less than or equal to 0.5 mu of superfine calcium borate, and also comprises a mixture consisting of the amorphous body and the crystals.

3. The amorphous or amorphous-containing article according to claim 1 is glass, glass fiber, ceramic glaze, enamel glaze, colored glaze, enamel, or the like.

4. The method of claim 1 wherein the calcium borate source is introduced without first heating (melting, sintering, firing) to form glass spheres, frits, and then heating the resultant product; and directly heated (melted, sintered and sintered) at one time, and then quenched to form amorphous products such as glass, glaze, enamel glaze and the like.

5. The calcium borate of claim 1 is introduced into an amorphous state, the melting temperature is reduced by 15-110 ℃, and the sintering and firing temperatures are reduced by 10-74 ℃; b is₂O₃The volatilization is reduced by 3-10%, and the dosage is reduced; meanwhile, 12-42% of fuel is saved; so the service life of the kiln is prolonged.

6. The article of manufacture of claim 1 having increased strength: the glass product is increased by 9-100%, the tensile strength of the glass fiber is increased by 9.2-18%, the hardness of the ceramic glaze and the enamel glaze is increased, the thermal expansion coefficient is small, a glass pressure bottle with the pressure of 0.3MPa can be manufactured, and a glass container, a ceramic product and an enamel product which are rapidly cooled at the temperature of 210-room temperature can be manufactured.

7. Calcium borate also has the function of replacing lead compounds or lead compound-containing compounds, natural minerals, industrial waste residues and the like. The product can be applied in oxidizing and reducing heating atmospheres, and is resistant to oxidation and free of color change for a long time; substituted PbO: B₂O₃The ratio of the amount of the compound (A) to the amount of the compound (B) is 1: 0.5 to 1.5mol (preferably 0.8 to 1.2 mol).

8. The calcium borate is used as raw material to replace boric acid and boron magnesium ore and is directly used for drawing glass fiber in a horseshoe kiln and a transverse flame kiln, and glass balls are not required to be manufactured firstly.

9. The glass fiber can be prepared in a tank furnace and a batch furnace by using calcium borate to replace colemanite and colemanite, the melting temperature is reduced by 15-50 ℃, the wire drawing temperature is reduced by 7-20 ℃, the fiber strength is increased by 9-15%, and the yield is increased by 6-12%.

10. The invention includes the complete substitution and the partial substitution of boric acid, borax, lead compounds, ascharite, colemanite and the like.