RO107246B1 - Producing process of a decorative covering (coating) for porcelain objects - Google Patents

Abstract

The invention relates to a process of obtaining a decorative coating for objects of porcelain. A mixture of 25 ... 40% kaolin, 20 ... 30% calcined alumina and 40 ... 60% silicon carbide waste. it wet grinding at a material ratio: balls, water 1: 1.5: 0.60 in the presence of 0.12% Na, CO 3 and 0.03% NaOH. The resulting Barbotine is applied on surfaces of porcelain objects, biscuits after which is covered with transparent glaze. products glaze is heated to 1300 ... 132 ° C.

Description

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The invention relates to a process for obtaining a decorative coating, for porcelain objects, by wet milling, of a mixture of raw materials, which is applied, as a bubble, on the surfaces of porcelain objects, biscuits. Over the applied layer, a transparent glaze is superimposed, and the glazed products are finally burnt.

Methods of obtaining glazes and decorative coatings are known as artistic glazes. The effect of these coatings is achieved by the use of opacities, pigments or overlapping layers of glaze.

When making these artistic glazes, it is necessary, in most cases, the irritation of the raw materials, the use of opacifiers and pigments, which are inaccessible, is inevitable.

At the same time, in the layers of overlapping glazes, there is the danger of their detachment from the sieve.

To make a decorative coating, for porcelain objects, without the use of deficient opacifiers, mix 25 ... 40% kaolin, 20 ... 30% calcined alumina and 40 ... 60% silicon carbide waste, crushed in advance. The mixture is wet-milled at a ratio of balls and water of 1: 1.5: 0.58, in the presence of 0.12% Na ^ COj and 0.03% NaOH. The resulting bubble is applied to the surfaces of porcelain, biscuit, brush, immersion or spray objects. Over the applied bubble, a layer of transparent, unfriteed glaze is sprayed. The glazed products are then burned at 1300 ... 1320 ° C.

By applying the process described in the invention, the following advantages are obtained:

- decorative coatings are made, for porcelain objects, without inaccessible opacifiers;

- a higher reuse of the waste is realized, by introducing in the recipe some pieces of crushed silicon carbide;

- Crushed silicon carbide is used, in the raw material recipe, as both an opacifier and as a modifier of the viscosity of the mixture as compared to the viscosity of the transparent glaze, which leads to a specific decorative effect of snake skin;

- Silicon carbide also provides a pleasant color (various shades of gray), without the use of any dye, but does not prevent the introduction of pigments, to obtain other colors.

An example of the process is given below.

The following raw materials are used to obtain a decorative, specific coating: Aghireș kaolin (STAS 232 / 1-76 C or D quality), calcined alumina, technical (STAS 1272 - 76 AAO quality) and silicon carbide waste (damaged pieces of board or castings, ground to a residue of R 009 = 8 ... 12%). For the transparent glaze, ordinary, unfrite porcelain glazes having an oxide composition, consisting of 63 ... 66% SiO ₂ , 9 ... 11% A1 ₂ O ₃ , maximum 0.5% Fe ₂ O ₃ , maximum 1.5% MgO, 9 ... 11% CaO and 4.5 ... 6% alkaline oxides. The listed raw materials are used to prepare the manufacturing recipe. The dosing is done by weighing, taking into account their humidity. The ratio of raw materials, expressed as a percentage, varies as follows: 15 ... 25% kaolin Aghireș, 5 ... 15% kaolin Harghita, 20 ... 30% calcined alumina, 40 ... 60% carbide waste of silicon. The milling of the raw materials is done on a wet basis, at a dry material ratio: water balls of 1: 1.5: 0.58, in two stages, using fluidizers: 0.12% Na ₂ CO ₃ and 0.03% NaOH. By grinding, the aim is to obtain a bubble with the following characteristics: minimum lithic weight, 1.62 kg / 1, residue of 4 ... 6% on the 0.063 mm sieve, and a humidity of 35 ... 40%. These parameters of the mixture, for the coating layer, ensure a good adhesion on the surface of the biscuit porcelain object, and the higher viscosity compared to that of the transparent glaze gives rise, after burning, to a decorative effect. The pieces thus covered (partially or completely) are glazed over the entire surface with transparent glaze and burn at 1300 ... 1320 ° C.

The characteristics of the decorative coatings obtained are: light gray-to-dark color, depending on the silicon carbide content, and in the case of adding dyes, colored coatings are obtained, determined by the color of the pigments used; opaque appearance, with embossed surface, having a snake skin effect.

For the decoration of the flower pots, made of porcelain, a coating mixture of 20% Aghireș kaolin, 9% Harghita kaolin, 24% calcined alumina and 47% silicon carbide waste is used.

The characteristics of the decorative coating are: light gray color, opaque type appearance, snake skin. The presented properties provide decorative coating, a wide possibility of use in the field of decorative ceramics and for domestic use, with special effects.

Claims (4)

Claim Process for obtaining a decoctional coating, for porcelain objects, by wet grinding, of a mixture of raw materials, containing milled silicon carbide waste, applying the resulting bubble on the surfaces of the biscuit porcelain objects, followed by glazing with a transparent glaze, having an oxide composition, consisting of 63 ... 66% SiO ₂ , 9 ... 11% 5 A1 ₂ O ₃ , maximum 0.5% Fe /} ,, maximum 1.5% MgO, 9 ... 11% CaO and 4.5 ... 6% alkali oxides, as well as the burning, finally, of the glazed products, characterized in that a mixture consisting of 25 is carried out. 10 ... 40% kaolin, 20 ... 30% calcined alumina and 40 ... 60% silicon carbide waste, the obtained mixture is ground, at a ratio to the grinding balls and water of 1: 1.5 : 0.60, in the presence of 0.12% Na / ZO, and 0.03% NaOH, 15 and after applying the bubble obtained on the surfaces of the porcelain, biscuit objects, over which, by spray, the transparent glaze is superimposed and the glazed products are burned, at a temperature of 1300 ... 20 1320 ° C.