Opacified glaze for dry-process production of post insulators, its preparation method and application

Abstract

The present invention relates to an opal glaze for dry production of post porcelain insulators, its preparation method and application, belonging to the technical field of dry preparation of post porcelain insulators. The opal glaze described in the present invention comprises raw materials with the following mass percentages: 13-17% of quartz powder, 5-9% of wollastonite, 22-26% of Korean feldspar, 14-17% of Datong clay, 4-7% of magnesite, 1.5-3% of barium carbonate, 0.5-2% of fluorite, 2-5% of spodumene, 6-9% of calcined talc, 12-17% of zirconium silicate, 5-10% of Longyan clay; additionally, 0.2-0.4% of self-made polyvinyl alcohol solution and 0.25-0.45% of dispersant are added. The formula design of the opal glaze of the present invention is scientific and reasonable, with high whiteness, good gloss, good high-temperature fluidity, uniform glaze layer thickness, smooth and flat surface, and no phenomena such as glaze shrinkage, orange peel glaze, and cracking, which can effectively improve the product strength; the present invention also provides a simple and feasible preparation method and application of the opal glaze.

Description

Technical Field

[0001] The present invention relates to an opal glaze for dry production of post porcelain insulators, a preparation method thereof and an application thereof, and belongs to the technical field of dry preparation of post porcelain insulators. Background Art

[0002] The glaze layer plays an important role in porcelain insulators. It can not only improve the strength, chemical stability and thermal stability of the insulators, but also improve the anti-pollution ability, etc. The glazed porcelain insulators have a pleasing luster. Different regions and countries have their own requirements for the glaze tone of insulators. In China, brown glaze products are basically used, and light-colored glaze porcelain insulator products such as opal glaze and blue-grey glaze are very commonly used in countries with less pollution such as Europe and America.

[0003] Domestic light-colored glaze products are mainly produced by wet processes. However, the wet forming process can only produce products with low voltage grades or low strength. Its forming process determines that the products cannot meet the requirements of high voltage grades and high strength. Porcelain insulator products with high voltage grades and high strength must be produced by dry processes.

[0004] In the traditional wet forming process, dipping glaze or pouring glaze is used for glazing. The glaze layer has a uniform thickness and generally does not have defects such as lack of glaze and shrinkage of glaze. However, the dry insulator forming process must use the method of manual spraying glaze, and it is very difficult to keep the glaze layer thickness uniform. The colorants used in traditional brown glazes play a fluxing role in the formula, reducing the high-temperature viscosity of the glaze and making it relatively easy to obtain a smooth and flat glaze surface. While the opal glaze is an opacifying glaze. Due to the introduction of the opacifier, the high-temperature viscosity of the glaze is increased, affecting the high-temperature fluidity of the glaze, and defects such as orange peel glaze, shrinkage of glaze or glaze cracks at the positions with thick glaze layers are likely to occur, seriously affecting the quality of the products.

[0005] CN201210309567.8 discloses a high-strength electroceramic grey glaze formula and a preparation method thereof, and CN201210151079.9 discloses a glaze material for grey glaze products in the dry forming process of electroceramics. The two patents are similar. Their basic glaze materials are white glaze bases, that is, basic glaze materials without adding colorants. Then, by appropriately adjusting the proportion and changing the colorants, grey glaze, sky blue glaze, brown glaze, etc. can be prepared. However, the above two patents only fire the basic white glaze, and the obtained products should be transparent or semi-transparent, and it is very difficult to obtain a smooth and flat surface. The colorants, in addition to having the ability to present color and cover, are also important fluxes.

[0006] After investigation, there are few reports at home and abroad on the production of high-voltage grade and high-strength opal glaze post porcelain insulator products by dry production processes. Summary of the Invention

[0007] The object of the present invention is to provide an opal glaze for dry production of post insulator porcelain, with a scientifically and reasonably designed formula, high whiteness, good glossiness, good high-temperature fluidity, uniform glaze layer thickness, smooth and flat surface, no phenomena such as glaze shrinkage, orange peel glaze, and cracking, and can effectively improve the product strength; the present invention also provides a simple and feasible preparation method and application of the opal glaze.

[0008] The opal glaze for dry production of post insulator porcelain according to the present invention comprises the following raw materials in mass percentage: quartz powder 13 - 17%, wollastonite 5 - 9%, Korean feldspar 22 - 26%, Datong clay 14 - 17%, magnesite 4 - 7%, barium carbonate 1.5 - 3%, fluorite 0.5 - 2%, spodumene 2 - 5%, calcined talc 6 - 9%, zirconium silicate 12 - 17%, Longyan clay 5 - 10%;

[0009] Based on the total mass of the above raw materials being 100% for measurement, additionally add 0.2 - 0.4% of self-made polyvinyl alcohol solution and 0.25 - 0.45% of dispersant.

[0010] The main component of the quartz powder is SiO2, which can improve the viscosity and melting temperature of the glaze, enhance the hardness and wear resistance of the glaze glass, and endow the glaze product with good chemical stability. Therefore, it is an indispensable raw material in the glaze.

[0011] The Fe2O3 content in the wollastonite is ≤0.5, and IL ≤ 4.0%. Wollastonite contains a large amount of CaO. Besides substituting part of the quartz, it can also play a role in promoting melting, and no gas is discharged during decomposition, which can eliminate the bubbles or glaze surface pinholes generated during the melting process of the glaze during high-temperature firing.

[0012] The Korean feldspar, barium carbonate, and calcined talc are important flux minerals, mainly acting as fluxes in the formula to ensure that the glaze has sufficient high-temperature fluidity at high temperatures. However, the appropriate proportion needs to be controlled to ensure good fluidity while not causing the initial melting temperature to be too low, so as to prevent the reduction of opalescence and the deterioration of covering power.

[0013] The Datong clay is the raw material after high-temperature calcination. The introduction of Datong clay mainly provides the SiO2 and Al2O3 components required in the formula to form a framework structure.

[0014] The Fe2O3 + TiO2 in the magnesite < 0.5%, and IL ≤ 0.5%. Magnesite can introduce MgO, assist in melting in the formula, can improve the whiteness of the opal glaze, and at the same time can reduce the expansion coefficient of the glaze.

[0015] The zirconium silicate is an opacifier, and its main function is to provide the opacity of the glaze, increase the covering power of the porcelain body surface, and maintain the opacification in various atmospheres without forming glaze shrinkage due to excessive crystallization; the simultaneously introduced fluorite (CaF2>85% in fluorite; Fe2O3+TiO2<0.5%), in addition to reducing the high-temperature viscosity of the glaze and increasing the whiteness of the glaze, will also promote the amount of opacifier in the zirconium glaze, refine the crystal grains, and improve the opacification effect.

[0016] In addition to providing SiO2 and Al2O3 required in the formula, the appropriate addition of the Longyan clay can improve the suspension and viscosity of the glaze slurry, contribute to the stability of the glaze slurry performance, and prevent precipitation; at the same time, it can make the glaze layer and the green body combine well and prevent the glaze layer from peeling off before firing.

[0017] In the spodumene, Fe2O3+TiO2<0.3% and IL≤0.5%. Spodumene can reduce the expansion coefficient of the glaze and improve the high-temperature fluidity of the glaze, but the dosage needs to be controlled, and too much will increase the firing temperature.

[0018] The self-made polyvinyl alcohol (PVA) solution can improve the suspension of the glaze slurry, and at the same time improve the adhesion ability and firing strength of the glaze slurry and the green body.

[0019] Preferably, the dispersant is one or both of CMC or 9300. The dispersant is added to improve the fluidity and suspension performance of the glaze slurry.

[0020] When designing the formula of the present invention, the suspension and fluidity of the glaze slurry are fully considered. The suspension of the glaze slurry is ensured by matching the proportions of the Longyan clay, the self-made PVA solution, and the dispersant; the fluidity of the glaze slurry is ensured by adjusting the addition amounts of the dispersant and water; the uniformity of the glaze layer composition is ensured by controlling the fineness and particle size distribution of the slurry; the controllability of the glaze layer thickness is ensured by adjusting the high-speed atomization spraying process and operation methods.

[0021] When designing the formula of the present invention, factors such as the whiteness, covering ability, high-temperature viscosity and fluidity, bonding strength, and product strength of the opal glaze layer are also considered. The specific concept is as follows:

[0022] In addition to improving the whiteness by strictly controlling the amount of coloring oxides by using high-purity or calcined raw materials, the whiteness of the glaze layer is also improved by magnesite and fluorite. Considering that the commonly used glaze for ceramic insulators is feldspar glaze of silicate type, which is basically transparent or semi-transparent glaze with the addition of a colorless agent, by adding an opacifier thereto, fine crystals, bubbles or devitrification phenomena can be generated in the glaze, which have a scattering effect on light, thereby obtaining an opaque opacified glaze surface. Zirconium silicate is similar in nature to the raw materials in the formulation system and is inexpensive, so it is used as an opacifier, and its opacifying degree is improved by the action of fluorite, thereby improving the uniformity and covering ability of its color. By adding different types of fluxes and significantly increasing their addition amounts, allowing them to play their respective roles and balance each other, the high-temperature viscosity of the glaze during firing is reduced, and its high-temperature fluidity is improved, solving problems such as orange peel glaze, shriveled glaze and glaze crack caused by the introduction of the opacifier. By introducing self-made PVA, the bonding force between the glaze slurry and the green body is improved, the interfacial fusion during firing is effectively improved, and the bonding strength between the glaze layer and the porcelain body is improved. At the same time, combined with magnesite and spodumene, the performance of reducing the expansion coefficient of the glaze layer can be achieved, forming a compressive stress glaze and improving the strength of the product.

[0023] Based on the above design, through the reasonable combination of various raw materials, the present invention not only ensures the suspension and fluidity of the glaze slurry during use, but also meets the high-temperature fluidity of the glaze and the ideal initial melting temperature, solving various defects in the preparation and application of the opal glaze.

[0024] The main differences between the present invention and the publicly disclosed CN201210309567.8 and CN201210151079.9 are as follows:

[0025] (1) The present invention does not add a colorant. Especially when fired in a reducing atmosphere, it is necessary for the opacifier to jointly produce an opacifying effect with other components in the formulation to achieve the purpose of improving the whiteness and covering ability, so as to prevent the yellowing of the parts with a thinner glaze layer and generate color difference.

[0026] (2) The present invention does not add a colorant and needs to add a large amount of flux to reduce the high-temperature viscosity of the glaze and improve its high-temperature fluidity at the same time.

[0027] (3) The present invention adds a self-made PVA solution, which can not only improve the adhesion ability of the glaze slurry to the green body, but also give full play to the role of the compressive stress glaze in improving the strength. The strength of the product after firing is increased by more than 16%.

[0028] (4) Using the formulation described in the present invention, it can be used for the wet forming preparation of ceramic insulators only by adding water for dilution.

[0029] In summary, the present invention has outstanding substantive features.

[0030] The preparation method of the opal glaze for dry production of post porcelain insulators comprises the following steps:

[0031] (1) Weigh the raw materials according to the mass percentage content, and put the raw materials into a high-speed planetary ball mill for ball milling;

[0032] (2) Conduct particle size testing on the ball-milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve and put it back into the mill. The glaze slurry particle size control standard is: <10μm: 69 ± 2%, D50: 4.7 ± 0.5μm;

[0033] (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating sieve to remove ferromagnetic impurities, and put it into a test glaze tank for aging. The aging time > 48h, and the glaze slurry flow rate is controlled at (27 ± 2)s.

[0034] The application of the opal glaze for dry production of post porcelain insulators includes the following steps:

[0035] (1) Put the aged glaze slurry into a clean pressure glaze tank, and conduct glazing tests on basic test samples such as white blanks or test bars that have met the conditions. The basic test samples such as white blanks or test bars that have met the conditions are porcelain insulator formula materials that have been pressed by dry cold isostatic pressing, trimmed by a trimming machine and have been put into the oven;

[0036] (2) The glazing adopts a high-speed atomization spraying process, and the flow rate of the glaze slurry is controlled by controlling the spraying pressure. The spraying pressure is controlled between 0.23 and 0.39 MPa; the glazed blank test samples after glazing are put into the drying oven for baking. The thickness of the glaze layer is 0.5 - 0.7 mm, and the drying oven temperature is 50 ± 5°C;

[0037] (3) After 72h - 96h in the drying oven, the glazed blank test samples in step (2) are loaded into the kiln for firing to obtain high-voltage rod-shaped post opal glaze porcelain insulator products.

[0038] Preferably, in step (3), the firing atmosphere is a reducing flame, and the firing curve is: room temperature - 120°C, 400 - 550 min; 120 - 120°C, 150 - 190 min; 120 - 340°C, 500 - 580 min; 640 - 850°C, 400 - 480 min; 850 - 970°C, 290 - 320 min; 970 - 980°C, 900 - 990 min; 980 - 1060°C, 260 - 330 min; 1060 - 1190°C, 350 - 430 min; 1190 - 1220°C, 160 - 220 min; 1220 - 1235°C, 240 - 290 min; 1235 - 1235°C - 1250 - 1250°C (the firing temperature range is 1235 - 1250°C), 20 - 40 min; 1235 - 1220°C, 90 - 120 min; 1220 - 1150°C, 180 - 230 min; 1150 - 900°C, 180 - 240 min; 900 - 180°C, 450 - 500 min.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The formula is simple and uses conventional raw materials for ceramic glaze. The prepared opal glaze has the advantages of high whiteness (whiteness > 55%), good gloss, good high-temperature fluidity, and uniform glaze layer thickness (the glaze layer thickness range after firing for the same piece is 0.3 - 0.5 mm), and has no obvious defects such as glaze shrinkage and pinholes;

[0041] (2) The compressive stress glaze formed by the present invention (the glaze and the body combine to form "compressive stress glaze") can effectively improve the product strength; among them, the linear expansion coefficient of the glaze is 6.6851×10 -6 K -1 (25 - 800 °C), and the linear expansion coefficient of the body is 6.9537×10 -6 K -1 (30 - 800 °C), and the average strength is increased by more than 16%;

[0042] (3) The post insulator products prepared by the present invention can cover various series of low, high, extra-high and ultra-high voltage levels, and are no longer restricted to the low-voltage products produced by the wet method;

[0043] (4) The present invention provides a technical reference for the dry preparation of high-voltage light-colored glaze insulators, and at the same time, because it is favored by foreign customers, it adds impetus to the export of insulators in China to the world. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a graph of the whiteness and high-temperature fluidity of the opal glaze;

[0045] Figure 2 is a drawing of the post insulator product prepared by the dry method. DETAILED DESCRIPTION OF THE INVENTION

[0046] The present invention will be further described below in conjunction with the embodiments, but it does not limit the implementation of the present invention.

[0047] All raw materials used except the polyvinyl alcohol solution are commercially available.

[0048] The self-made polyvinyl alcohol solution is prepared by boiling polyvinyl alcohol with a solid content of 25 wt% at 80 ± 10 °C.

[0049] Example 1

[0050] A milky white glaze for dry production of post insulator, comprising raw materials with the following mass percentages: quartz powder 16%, wollastonite 6%, Korean feldspar 22%, Datong clay 16%, magnesite 5%, barium carbonate 2%, fluorite 1%, spodumene 3%, calcined talc 8%, zirconium silicate 13%, Longyan clay 8%, additionally 0.25% of self-made polyvinyl alcohol solution, and additionally 0.25% of dispersant (CMC).

[0051] The preparation and application process of the milky white glaze sample for dry production of post insulator is as follows:

[0052] (1) Weigh the raw materials and put them into a high-speed planetary ball mill for ball milling.

[0053] (2) Conduct particle size test on the ball-milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve and put it back into the mill. Glaze slurry particle size: <10μm: 67.3%, D50: 5.03μm.

[0054] (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating sieve to remove ferromagnetic impurities, and put it into a test glaze tank for aging. The aging time is 60h, and the glaze slurry flow rate is 28.7s.

[0055] (4) Put the aged glaze slurry in step (3) into a clean pressure glaze tank, and conduct glazing test on the white blank test strips with a diameter of 18mm that have met the glazing conditions. Each group of test strips is 7 pieces.

[0056] (5) The white blank test strips in step (4) are glazed by high-speed atomization spraying process. The spraying pressure is 0.30MPa. After glazing, the glazed blank test strips are put into a drying room for baking. The glaze layer thickness is 0.57mm, and the drying room temperature is 50°C.

[0057] (6) After 72h in the drying room, the glazed blank test strips in step (5) are loaded into the kiln for firing.

[0058] The firing curve of the milky white glaze test strips in step (6) is: room temperature to 120°C, 450min; 120 to 120°C, 180min; 120 to 340°C, 530min; 640 to 850°C, 450min; 850 to 970°C, 290min; 970 to 980°C, 900min; 980 to 1060°C, 300min; 1060 to 1190°C, 400min; 1190 to 1220°C, 180min; 1220 to 1245°C, 250min; 1245 to 1245°C, 20min; 1245 to 1220°C, 90min; 1220 to 1150°C, 180min; 1150 to 900°C, 200min; 900 to 180°C, 480min.

[0059] Test effects of applying the above formula and preparation method:

[0060] After firing, the glaze layer thickness distribution of the test strip is 0.34 - 0.45 mm; the whiteness of the opal glaze is 61%; it has good covering ability, no exposed bottom and yellowing phenomenon, and no glaze shrinkage and cracking phenomenon; through the flexural strength test, after removing the maximum and minimum values, the average strength of the porcelain strip with opal glaze is 183.7 MPa.

[0061] Example 2

[0062] An opal glaze for dry production of post porcelain insulators comprises raw materials with the following mass percentages: quartz powder 15%, wollastonite 7%, Korean feldspar 24%, Datong clay 16%, magnesite 6%, barium carbonate 1.5%, fluorite 0.5%, spodumene 4%, calcined talc 7%, zirconium silicate 14%, Longyan clay 5%, additionally 0.25% of self-made polyvinyl alcohol solution, and additionally 0.35% of dispersant (9300).

[0063] The preparation and application process of the opal glaze sample for dry production of post porcelain insulators is as follows:

[0064] (1) Weigh the raw materials and ball mill them in a high-speed planetary ball mill.

[0065] (2) Test the particle size of the ball milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve and put it back into the mill. Glaze slurry particle size: <10μm: 70.7%, D50: 4.61μm.

[0066] (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating sieve to remove ferromagnetic impurities, and put it into a test glaze tank for aging. The aging time is 48 h, and the glaze slurry flow rate is 26.9 s.

[0067] (4) Load the aged glaze slurry in step (3) into a clean pressure glaze tank, and conduct a glazing test on white blank test strips with a diameter of 18 mm that have met the glazing conditions. Each group of test strips has 7 pieces.

[0068] (5) The white blank test strips in step (4) are glazed by high-speed atomization spraying process. The spraying pressure is 0.30 MPa. After glazing, the glazed blank test strips are put into a drying oven for baking. The glaze layer thickness is 0.68 mm, and the drying oven temperature is 55°C.

[0069] (6) After 72 h in the drying oven, load the glazed blank test strips into the kiln for firing.

[0070] In step (6), the firing curve of the opal glaze test strip is as follows: room temperature to 120 °C, 450 min; 120 to 120 °C, 170 min; 120 to 340 °C, 530 min; 640 to 850 °C, 440 min; 850 to 970 °C, 300 min; 970 to 980 °C, 900 min; 980 to 1060 °C, 280 min; 1060 to 1190 °C, 370 min; 1190 to 1220 °C, 200 min; 1220 to 1240 °C, 260 min; 1240 to 1240 °C, 20 min; 1240 to 1220 °C, 90 min; 1220 to 1150 °C, 180 min; 1150 to 900 °C, 200 min; 900 to 180 °C, 450 min.

[0071] Test effects of applying the above formula and preparation method:

[0072] After firing, the glaze layer thickness distribution of the test strip is 0.39 - 0.48 mm; the whiteness of the opal glaze is 67%; the covering ability is good, there is no phenomenon of exposed bottom and yellowing, and no phenomenon of glaze shrinkage and cracking; through the flexural strength test, removing the maximum and minimum values, the average strength of the porcelain strip with opal glaze is 201.2 MPa.

[0073] Example 3

[0074] An opal glaze for dry production of post porcelain insulators, comprising raw materials with the following mass percentages: quartz powder 13%, wollastonite 8%, Korean feldspar 25%, Datong soil 15%, magnesite 4%, barium carbonate 2%, fluorite 2%, spodumene 2%, calcined talc 7%, zirconium silicate 14%, Longyan soil 8%, plus 0.30% of self-made polyvinyl alcohol solution, plus 0.40% of dispersant (9300).

[0075] The preparation and application process of the opal glaze sample for dry production of post porcelain insulators are as follows:

[0076] (1) Weigh the raw materials and put them into a high-speed planetary ball mill for ball milling;

[0077] (2) Conduct particle size testing on the ball-milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve and put it back into the mill. Glaze slurry particle size: <10 μm: 68.4%, D50: 4.81 μm;

[0078] (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating sieve to remove ferromagnetic impurities, and place it in a test glaze tank for aging. The aging time is 64 h, and the glaze slurry flow rate is 25.3 s;

[0079] (4) Load the aged glaze slurry in step (3) into a clean pressure glaze tank and conduct glazing tests on the white blanks of model 2865 that have met the glazing conditions;

[0080] (5) The green body in step (4) is glazed by a high-speed atomizing spraying process, the spraying pressure is 0.35 MPa, and the glazed green body test strip after glazing is put into a drying oven for baking. The thickness of the glaze layer is 0.62 mm, and the temperature of the drying oven is 50 °C;

[0081] (6) The milky white glazed green body product in step (5) is loaded into a kiln for firing after 80 h in the drying oven.

[0082] The firing curve of the milky white glazed green body product in step (6) is: room temperature to 120 °C, 530 min; 120 - 120 °C, 180 min; 120 - 340 °C, 580 min; 640 - 850 °C, 450 min; 850 - 970 °C, 300 min; 970 - 980 °C, 950 min; 980 - 1060 °C, 300 min; 1060 - 1190 °C, 400 min; 1190 - 1220 °C, 200 min; 1220 - 1248 °C, 275 min; 1248 - 1248 °C, 25 min; 1248 - 1220 °C, 120 min; 1220 - 1150 °C, 220 min; 1150 - 900 °C, 230 min; 900 - 180 °C, 480 min.

[0083] Test effects of applying the above formula and preparation method:

[0084] After firing, the thickness distribution of the glaze layer of the product is 0.32 - 0.45 mm; the whiteness of the milky white glaze is 64%; the covering ability is good, there is no phenomenon of exposed bottom and yellowing, and there is no phenomenon of glaze shrinkage and cracking; the product is subjected to a bending failure test, the designed rated force value is 8 kN, and the actual force value is 13.73 kN.

[0085] Comparative Example 1

[0086] A milky white glaze for dry production of post porcelain insulators comprises raw materials with the following mass percentages: quartz powder 15%, wollastonite 7%, Korean feldspar 24%, Datong soil 16%, magnesite 6%, barium carbonate 1.5%, fluorite 0.5%, spodumene 4%, calcined talc 7%, zirconium silicate 14%, Longyan soil 5%, and additionally 0.35% of dispersant (9300).

[0087] The formula of Comparative Example 1 is based on Example 2 and removes the self-made polyvinyl alcohol solution.

[0088] The preparation and application process of the milky white glaze sample for dry production of post porcelain insulators are as follows:

[0089] (1) Weigh the raw materials and put them into a high-speed planetary ball mill for ball milling;

[0090] (2)Perform particle size testing on the ball-milled glaze slurry. After meeting the glaze slurry particle size control standard, sieve it and discharge it from the mill. Glaze slurry particle size: <10μm: 70.2%, D50: 4.68μm;

[0091] (3)Pass the glaze slurry obtained in step (2) through an iron-removing vibrating sieve to remove ferromagnetic impurities, and place it in a test glaze tank for aging. The aging time is 48h, and the glaze slurry flow rate is 27.5s;

[0092] (4)Load the aged glaze slurry in step (3) into a clean pressure glaze tank, and conduct glazing tests on white blank test strips with a diameter of 18mm that have met the glazing conditions. Each group of test strips consists of 7 pieces;

[0093] (5)The white blank test strips in step (4) are glazed by high-speed atomization spraying process. The spraying pressure is 0.30MPa. After glazing, the glazed blank test strips are placed in a drying oven for baking. The glaze layer thickness is 0.65mm, and the drying oven temperature is 55°C;

[0094] (6)Load the glazed blank test strips in step (5) into the kiln for firing after 72h in the drying oven.

[0095] The firing curve of the opal glaze test strips in step (6) is as follows: room temperature to 120°C, 450min; 120 to 120°C, 170min; 120 to 340°C, 530min; 640 to 850°C, 440min; 850 to 970°C, 300min; 970 to 980°C, 900min; 980 to 1060°C, 280min; 1060 to 1190°C, 370min; 1190 to 1220°C, 200min; 1220 to 1240°C, 260min; 1240 to 1240°C, 20min; 1240 to 1220°C, 90min; 1220 to 1150°C, 180min; 1150 to 900°C, 200min; 900 to 180°C, 450min.

[0096] Test effects of applying the above formula and preparation method:

[0097] After firing, the glaze layer thickness distribution of the test strips is 0.34 - 0.45mm; the whiteness of the opal glaze is 57%; the covering ability is strong, there is no yellowing phenomenon, and there is no glaze shrinking or cracking phenomenon; through the flexural strength test, after removing the maximum and minimum values, the average strength of the porcelain strips with opal glaze is 184.2MPa.

[0098] Comparative Example 2

[0099] A milky white glaze for dry production of post insulator porcelain includes raw materials with the following mass percentages: quartz powder 15%, wollastonite 7%, Korean feldspar 20%, Datong clay 16%, magnesite 6%, barium carbonate 1.5%, fluorite 0.5%, spodumene 4%, calcined talc 7%, zirconium silicate 14%, Longyan clay 9%, additionally 0.25% of self-made polyvinyl alcohol solution, and additionally 0.35% of dispersant (9300).

[0100] The formulation of Comparative Example 2 is based on Example 2, with a 4% reduction in the amount of Korean feldspar used and a 4% increase in the amount of Longyan clay used.

[0101] The preparation and application process of the milky white glaze sample for dry production of post insulator porcelain is as follows:

[0102] (1) Weigh the raw materials and put them into a high-speed planetary ball mill for ball milling;

[0103] (2) Conduct a particle size test on the ball-milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve and put it back into the mill. Glaze slurry particle size: <10μm: 71.3%, D50: 4.47μm;

[0104] (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating screen to remove ferromagnetic impurities, and place it in a test glaze tank for aging. The aging time is 48h, and the glaze slurry flow rate is 33s;

[0105] (4) Load the aged glaze slurry in step (3) into a clean pressure glaze tank, and conduct a glazing test on white blank test strips with a diameter of 18mm that have met the glazing conditions. Each group of test strips is 7 pieces;

[0106] (5) The white blank test strips in step (4) are glazed by high-speed atomization spraying process. The spraying pressure is 0.30MPa. After glazing, the glazed blank test strips are put into a drying oven for baking. The glaze layer thickness is 0.66mm, and the drying oven temperature is 55°C;

[0107] (6) After 72h in the drying oven, the glazed blank test strips in step (5) are loaded into the kiln for firing.

[0108] In step (6), the firing curve of the opal glaze test strip is as follows: room temperature to 120 °C, 450 min; 120 to 120 °C, 170 min; 120 to 340 °C, 530 min; 640 to 850 °C, 440 min; 850 to 970 °C, 300 min; 970 to 980 °C, 900 min; 980 to 1060 °C, 280 min; 1060 to 1190 °C, 370 min; 1190 to 1220 °C, 200 min; 1220 to 1240 °C, 260 min; 1240 to 1240 °C, 20 min; 1240 to 1220 °C, 90 min; 1220 to 1150 °C, 180 min; 1150 to 900 °C, 200 min; 900 to 180 °C, 450 min.

[0109] Test effects of applying the above formula and preparation method:

[0110] After firing, the thickness distribution of the glaze layer of the test strip is 0.33 - 0.49 mm, and the glaze layer distribution is uneven; the whiteness of the opal glaze is 57%; slight glaze shrinkage occurs; through the flexural strength test, after removing the maximum and minimum values, the average strength of the porcelain strip with opal glaze is 178.4 MPa.

[0111] Comparative Example 3

[0112] An opal glaze for dry production of post porcelain insulators comprises raw materials with the following mass percentages: quartz powder 15%, wollastonite 7%, Korean feldspar 24%, Datong clay 16%, magnesite 6%, barium carbonate 1.5%, fluorite 0.5%, spodumene 4%, calcined talc 7%, zirconium silicate 14%, Longyan clay 5%, with an additional 0.25% of self-made polyvinyl alcohol solution and an additional 0.35% of dispersant (9300).

[0113] Comparative Example 3 directly uses the formula and glaze slurry of Example 2 and changes the glaze layer thickness.

[0114] The preparation and application process of the opal glaze sample for dry production of post porcelain insulators are as follows:

[0115] (1) Weigh the raw materials and put them into a high-speed planetary ball mill for ball milling;

[0116] (2) Conduct particle size testing on the ball-milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve and put it back into the mill. Glaze slurry particle size: <10 μm: 70.7%, D50: 4.61 μm;

[0117] (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating screen to remove ferromagnetic impurities, and put it into a test glaze tank for aging. The aging time is 48 h, and the glaze slurry flow rate is 18 s;

[0118] (4) The aged glaze slurry in step (3) is filled into a clean pressure glaze tank, and a glazing test is carried out on the white blank test strips with a diameter of 18 mm that have met the glazing conditions. Each group of test strips consists of 7 pieces.

[0119] (5) The white blank test strips in step (4) are glazed by the wet method. Wipe the test strips with a wet cloth in a circle to keep the humidity, then immerse the white blank test strips in the glaze slurry for 3 s and then lift them up, and place them in a shady place to dry naturally. The thickness of the glaze layer is 0.62 mm, and the temperature of the drying room is 55 °C.

[0120] (6) The glazed blank test strips in step (5) are loaded into the kiln for firing after 72 h in the drying room.

[0121] The firing curve of the opal glaze test strips in step (6) is as follows: room temperature to 120 °C, 450 min; 120 to 120 °C, 170 min; 120 to 340 °C, 530 min; 640 to 850 °C, 440 min; 850 to 970 °C, 300 min; 970 to 980 °C, 900 min; 980 to 1060 °C, 280 min; 1060 to 1190 °C, 370 min; 1190 to 1220 °C, 200 min; 1220 to 1240 °C, 260 min; 1240 to 1240 °C, 20 min; 1240 to 1220 °C, 90 min; 1220 to 1150 °C, 180 min; 1150 to 900 °C, 200 min; 900 to 180 °C, 450 min.

[0122] Test effects of applying the above formula and preparation method:

[0123] After firing, the thickness distribution of the glaze layer on the test strips is 0.31 - 0.38 mm; the whiteness of the opal glaze is 63%; the covering ability is good, there is no phenomenon of exposed bottom and yellowing, and there is no phenomenon of glaze shrinkage and cracking; through the flexural strength test, removing the maximum and minimum values, the average strength of the porcelain strips with opal glaze is 195.7 MPa.

[0124] Summarize the test effects of applying the above formula and preparation method and collate the data into Table 1.

[0125] Table 1 Test data of applying the formula and preparation method

[0126]

[0127] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A milky white glaze for dry production of post porcelain insulators, characterized in that: The raw materials include the following mass percentages: quartz powder 13 - 17%, wollastonite 5 - 9%, Korean feldspar 22 - 26%, Datong clay 14 - 17%, magnesite 4 - 7%, barium carbonate 1.5 - 3%, fluorite 0.5 - 2%, spodumene 2 - 5%, calcined talc 6 - 9%, zirconium silicate 12 - 17%, Longyan clay 5 - 10%; Based on the sum of the masses of the above raw materials being 100% for measurement, additionally add 0.2 - 0.4% of self-made polyvinyl alcohol solution and 0.25 - 0.45% of dispersant; The self-made polyvinyl alcohol solution is made by boiling polyvinyl alcohol with a solid content of 20 - 30 wt% at 70 - 90 °C.

2. The opal glaze for dry production of post insulator according to claim 1, characterized in that: The content of Fe2O3 in wollastonite ≤ 0.5, IL ≤ 4.0%; the content of Fe2O3 + TiO2 in magnesite < 0.5%, IL ≤ 0.5%.

3. The opal glaze for dry production of post porcelain insulators according to claim 1, characterized in that: The content of CaF2 in fluorite > 85%; Fe2O3 + TiO2 < 0.5%; the content of Fe2O3 + TiO2 in spodumene < 0.3%, IL ≤ 0.5%.

4. A preparation method of an opal glaze for dry production of post porcelain insulators according to any one of claims 1-3, characterized in that: It includes the following steps: (1) Weigh each raw material according to the mass percentage, and put the raw materials into a ball mill for mixing and ball milling; (2) Conduct particle size testing on the ball-milled glaze slurry. After reaching the glaze slurry particle size control standard, sieve it and put it back into the mill; (3) Pass the glaze slurry obtained in step (2) through an iron-removing vibrating sieve to remove ferromagnetic impurities, and then put it into a test glaze tank for aging to obtain the opal glaze for dry-method production of post insulators.

5. The preparation method of the opal glaze for dry production of post porcelain insulators according to claim 4, characterized in that: In step (2), the glaze slurry particle size control standard: <10μm: 69 ± 2%, D50: 4.7 ± 0.5μm; in step (3), the aging time > 48h, and the glaze slurry flow rate is controlled at (27 ± 2) s.

6. Use of the opal glaze for dry production of post porcelain insulators according to any one of claims 1-3, characterized in that: It includes the following steps: (1) Load the opal glaze into a pressure glaze tank and conduct glazing tests on the basic test pieces that have met the conditions; (2) The glazing in step (1) adopts a high-speed atomization spraying process. Control the flow rate of the glaze slurry by controlling the spraying pressure. After glazing, put the glazed green body test pieces into a drying oven for baking; (3) Load into the kiln for firing to obtain high-voltage rod-shaped post opal glaze porcelain insulator products.

7. Use of the opal glaze for dry production of post porcelain insulators according to claim 6, characterized in that: In step (1), the basic test pieces that meet the conditions are the green bodies that have been dry cold isostatically pressed, trimmed by a trimming machine and have been put into the drying oven.

8. The application of the opal glaze for dry production of post porcelain insulators according to claim 6, characterized in that: In step (2), the glaze layer thickness is 0.5 - 0.7mm; in the high-speed atomization spraying process, the spraying pressure is controlled at 0.23 - 0.39MPa; the drying oven temperature is 50 ± 5 °C; the baking time is 72 - 96h.

9. The application of the opal glaze for dry production of post porcelain insulators according to claim 6, characterized in that: In step (3), the firing atmosphere is a reducing flame, the firing temperature is 1235 - 1250 °C, and the firing curve is: room temperature - 120 °C, 400 - 550min; 120 - 120 °C, 150 - 190min; 120 - 340 °C, 500 - 580min; 640 - 850 °C, 400 - 480min; 850~970 °C, 290~320 min; 970~980 °C, 900~990 min; 980~1060 °C, 260~330 min; 1060~1190 °C, 350~430 min; 1190~1220 °C, 160~220 min; 1220~1235 °C, 240~290 min; 1235~1235 °C - 1250~1250 °C, 20~40 min; 1235~1220 °C, 90~120 min; 1220~1150 °C, 180~230 min; 1150~900 °C, 180~240 min; 900~180 °C, 450~500 min.

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