RU2405760C1 - Engobe - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the industry of ceramics, specifically to decoration of single-burning ceramic tiles by for internal lining. The engobe contains the following, wt %: kaolin 10, frit 50-60; quartz sand 15-20, alkaline crude kaolin 15-20.

EFFECT: improved decorative properties of the obtained coating and improved physical and mechanical characteristics.

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Description

The invention relates to the ceramic industry, in particular to the production of single-fired ceramic tiles for internal cladding.

The known composition of engobe for the production of tiles with the following ratio of components [1]:

clay component 45-75;

silica sand 0-25;

glaze and / or frit 15-50;

pigment 0-10.

The disadvantage of this ceramic mass is the increased content of the clay component, which negatively affects the degree of whiteness of the resulting coating.

Closest to the proposed is the composition of engobe [1], taken as a prototype, which includes (wt.%):

white clay 45-75;

silica sand 0-25;

glaze and / or frit 15-35;

pigment 0-10.

The disadvantage of the prototype is the increased viscosity of the engobe slip, associated with a high clay content, which necessitates the use of expensive electrolytes, which in some cases lead to loosening of the sintered coating. The low density of the engobic layer determines the increased consumption of glaze, which is associated with its flowing into open pores. In addition, the use of white-burning clay does not allow to obtain a decorative coating of sufficient whiteness, which becomes a paramount task when decorating a ceramic crock, which includes red-burning clay.

The aim of the invention is to significantly increase the whiteness of the resulting engobe coating, which is especially relevant when using transparent glazes, overglaze decoration and the use of red-burning clay in a ceramic crock.

An engobe of this composition can be used in decorating ceramic tiles for internal cladding, produced by the technology of single firing. The composition of the engobe includes frit (50-60%), quartz sand (15-20%), kaolin (10%), alkaline unenriched kaolin (15-20%). Introduction to the composition of alkaline kaolin can significantly improve the decorative properties of the resulting coating. The engobe includes accessible and widespread components (Table 1).

Replacing clay in the engobe allows you to get a durable coating with enhanced aesthetic properties and low fire shrinkage. The introduction of unenriched alkaline kaolin into the mass also reduces the cost of production, since this component differs significantly from the traditional kaolin in mineralogical composition, it contains a large amount of alkaline and alkaline-earth oxides that intensify the sintering process (Table 2). In addition, alkaline kaolin has a low cost, and its deposits have a sufficient supply.

Preparation of engobe was carried out by the slip method in a ball mill, with a ratio of grinding media: material = 2: 1. The grinding was carried out to a residue on sieve No. 0063 of not more than 2%. The moisture content of the resulting slurry was 40%; application to the surface of the product was carried out by irrigation. Firing was carried out at a temperature of 1050 ° C. The proposed engobe has high physico-mechanical and aesthetic properties (Table 3) and can be used for ceramic tiles of various compositions.

Information sources

1. Application of Russia No. 2006133888/03, 09/22/2006.

Table 1 Engob compositions Component Name The content in the mixture,% by weight Proposed option Prototype one 2 White clay - - 45-75 Kaolin 10 10 - Frit fifty 60 15-35 Quartz sand twenty fifteen 0-25 Alkaline unenriched kaolin twenty fifteen - Pigment - - 0-10

table 2 The chemical composition of the raw materials used Materials Mass content,% Amount SiO ₂ Fe ₂ O ₃ Al ₂ O ₃ TiO ₂ Cao MgO K ₂ O + Na ₂ O Zno B ₂ O ₃ SO ₃ P.P.P. Kaolin 46.80 0.60 36,20 0.28 0.90 0.63 1.25 - - - 13.25 99.91 Alkaline unenriched kaolin 68.90 0.45 18.24 0.21 1.22 0.11 5.70 0.31 4.80 99.94 Quartz sand 99.14 0.04 0.70 - - - - - - - 0.12 99.99 Frit 58.67 - 7.96 - 9.66 2.80 7.83 4.08 8.82 - - 99.82

Table 3 Afterburning properties of engobe coating Name of characteristics Calcined Shard Characteristics one 2 Air shrinkage,% 1,50 1.58 Water absorption,% 2.12 2.01 Fire shrinkage,% 6.50 6.30 Porosity,% 4.80 4,55 Density, g / cm ³ 2.05 2.10 Reflection coefficient,% according to MS-20 76 78

Claims (1)

An engobe intended for decorating ceramic tiles of single firing using transparent glazes, overglaze pigments and / or incorporating red-burning clay into a ceramic shard, including kaolin, frit, quartz sand, characterized in that instead of clay it contains a mixture of kaolin and unenriched alkaline kaolin in the following the ratio of components, wt.%:
kaolin 10 frit 50-60 quartz sand 15-20 alkaline non-enriched kaolin 15-20