SU1730062A1 - Opacifier composition for porcelain glaze - Google Patents

Abstract

Use: manufacture of fine ceramic products, in particular, production of hard porcelain, calcined in the temperature range 1380-1410 ° C, and can be used in the manufacture of artistic and household porcelain. The essence of the invention: the silencer contains zircon 40.0-45.0%, BF ZrSiO, dolomite 55.0-60.0%, BF CaCO3 -MdCO3. Characteristics: sintering temperature 1320-1400 ° C, glaze preparation time 40 hours, glaze coated whiteness, 70%. 2 tab.

Description

The invention relates to the production of fine ceramic products, in particular, to the production of solid porcelain, calcined in the temperature range of 1380-1410 ° C, and can be used in the manufacture of artistic and household porcelain.

The known composition of the silencer for ceramic glaze, including zircon and calcium carbonate in the following ratio, wt.%:

Zircon Calcite

46.4-82.2 17.8-53.6

The disadvantages of this silencer are the need for pre-grinding; the whiteness of the glaze coating is not high enough;

The purpose of the invention is to increase the whiteness of the sintering temperature and shorten the cooking time of the stewed glaze.

The goal is achieved by the fact that the composition of the muffler contains dolomite as carbonate in the following ratio, wt.%:

Zircon Dolomite

40.0-45.0 55.0-60.0

The proposed muffler composition makes it possible to obtain with its use a high-temperature jammed coating with high whiteness while reducing the duration of the preparation of jammed glaze.

The silencer has the following chemical composition, wt.%:

with

WITH

vi

CJ

Ltd

hO

ZrOa Si02 CaO MgO

26.9-30.2 13.1-14.8 16.7-18.2 12.0-13.0

C02

26.3-28.8

These oxides are introduced into the silencer in the form of the zircon mineral ZrSi04 (Zr02 SiO.) And the dolomite mineral (CaCO3 -MdCO3).

Zircon serves as a coating for the main damping phase due to the formation of fine crystals in the glaze glass matrix, which have a high refractive index and cause diffuse scattering of the light incident on the surface, which in turn prevents light from passing to the surface of the ceramic shard and reflection of light from this surface . Dolomite, which is part of the jamming mixture, contributes (during sintering the silencer) to the formation of a series of compounds such as calcium and magnesium zirconsilicates, which during the preparation of the glaze (grinding of the charge and roasting) are destroyed to form extremely small zirconium crystals and zirconia. Thus, the presence of dolomite in the muffler composition increases the efficiency of killing glaze glass with zirconium compounds, and as a result, the whiteness of the glazed surface increases with the dispersion of the zircon silencing phase.

The given charge composition of the silencers, namely, the content of zircon and dolomite within the specified limits, is optimal. When the zircon content decreases below 40% and, accordingly, the dolomite content increases above 60%, the silencer introduces a large amount of calcined calcium and magnesium oxides into the glaze, which adversely affects the rheological properties of the glaze slurry and further degrades the quality of the glaze coating.

When preparing a silencer from a mixture of zircon with calcite (calcium carbonate) using the prototype technology, the sintering temperature of the silencer should not exceed 1250 ° C, since at a higher temperature the material of the container dissolves in the mixture. Replacing the calcite silencer with dolomite makes it possible to increase the sintering temperature of the silencer to 1320–1410 ° C due to the low reactivity of dolomite with respect to porcelain and thus makes it possible to produce a silencer in porcelain roasting furnaces and not install additional thermal units in the plants.

The increase in the total carbonate content in the charge composition of the muffler as compared with the prototype allows an increase in the efficiency of the process of destruction of zircon crystals and the formation of zirconsilicates during sintering. As a result, the silencer obtained during sintering does not require additional grinding, which makes it possible to shorten the preparation time of the glaze slurry by 40-45%.

The following raw materials are used for the preparation of the silencer: Zircon concentrate KCP, OST 48-82-81; dolomite lumpy for the glass industry. GOST 23672-79. The silencer is prepared as follows.

Lump dolomite is cleaned and sorted, then crushed on runners with granite or quartzite rollers and hearths with a vibrating sieve and magnetic separator. Zircon concentrate and dolomite are weighed and mixed either in a ball mill by dry mixing at a M: W ratio of 1: 0.8 for 2 h, or by double passing through a 37 hole sieve / cm. Mixed materials are loaded into fireclay or porcelain containers. The mixture is subjected to calcination at 1320-1400 ° C in any heating unit that provides exposure at a maximum temperature of at least 30 minutes. The calcined mixture of dolomite and zircon extracted from the containers is a ready-made muffler, suitable for further use for making jammed glaze.

PRI me R 1. Pre-crushed dolomite and zircon concentrate in quantities corresponding to the content, wt.%: Zircon 40; dolomite 60, loaded into a ball mill drum. Flint pebbles were also loaded there with the ratio M; W 1: 0.8. The mixture of zircon and dolomite was mixed in a ball mill for 2 hours. Then the mixture was discharged from the ball mill and put into porcelain containers or in chamotte boxes closed on top and placed in the bottom part of the porcelain roasting trolley. After calcining the mixture at 1320-1410 ° C, the finished muffler was removed from the containers and loaded into the ball mill drum along with the initial components of the porcelain glaze. After co-grinding of the mixture by wet grinding, the glaze slurry was subjected to sieve and magnetic enrichment and was applied to the glazing area of the products. Glazing and roasting of products were carried out according to the technology for producing porcelain products at a roasting temperature of 1380-1410 ° C. After firing, the products had a whiteness of 70-72% with a good quality glazed surface. Characteristics of the developed formulations silencers for porcelain glazes are presented in Table. 2

PRI mme R 2. Technology preparation of the muffler of example 1 in the following ratio of components, wt.%:

Zircon Dolomite

45.0; 55.0.

Example 3: Preparation technology for a silencer of Example 1 with the following ratio of components, wt%:

Zircon Dolomite

42; 58.

From the analysis of data table. 2, it can be concluded that using a developed silencer, calcined at a high temperature, it is possible to obtain porcelain glazed glazes with high whiteness and firing temperature, while.

The scaffold proposed in the prototype makes it impossible to obtain high-temperature glazes for porcelain with high whiteness while maintaining the initial glaze preparation time.

The expected economic effect from the implementation of the invention is obtained by increasing the quality of the glaze coating and the grade of the products.

Claims (1)

Invention Formula The composition of the silencer for porcelain glaze, including zircon and alkali metal carbonate, is from the fact that, in order to increase whiteness, sintering temperature and reduce the duration of glaze preparation, it contains dolomite as carbonate in the following ratio , wt.%: Zircon Dolomite 40.0-45.0 55.0-60.0 The composition of the silencers Table2 Characteristics of the developed formulations of silencers for forfor glazes Table 1