RU2283291C1 - Charge for production of the blue color ceramic pigment - Google Patents

Abstract

FIELD: ceramic industry; production of ceramic pigments for decoration of the whiteware and majolica products.

SUBSTANCE: the invention is pertaining to ceramic industry, in particular to the field of production of the ceramic pigments for decoration of the whiteware and majolica products. The technical result of the invention is reduction of the temperature of the pigment synthesis and improvement of its color properties. The charge for production of the ceramic pigment contains: talcum, Al₂О₃, SiO₂, CoO, and additionally contains the topaz concentrate at the following contents of the components (in mass %): Talcum - 41.0-42.9; Al₂О₃ - 23.0-30.8; SiO₂ - 23.1-23.7; CoO - 2.1-8.4; the topaz concentrate - 2.0-3.0. The pigment synthesis temperature is 1100-1200°С. The pigment is recommended for production of the underglaze and overglaze ceramic paints used for the ceramic masses coloring.

EFFECT: the invention ensures production of the underglaze and overglaze ceramic paints used for the ceramic masses coloring.

1 ex, 3 tbl

Description

The scope of the invention is the production of ceramic pigments, paints.

In the synthesis of cordierite by means of solid-phase reactions, it was found that for the preparation of charge mixtures different starting materials can be used, the oxide content of which provides the stoichiometric composition of cordierite. Most often, mixtures of talc, high-quality refractory clays and industrial alumina are used to obtain cordierite under industrial conditions. When firing these mixtures, the onset of cordierite formation lies in the temperature range 1000-1270 ° C. Actively is the formation of cordierite at temperatures of 1200-1380 ° C. When the temperature rises to 1400-1450 ° C, cordierite melts with decomposition. The speed of the solid-phase reaction is regulated by the introduction of additives (Avvakumov E.G., Gusev A.A. Cordierite - a promising ceramic material // - Novosibirsk, 1999).

Cordierite after the introduction of the corresponding chromophore additives into it can be used as pigments.

A disadvantage of the traditional technology for producing ceramic pigments is the use of pure chemicals as raw materials, which leads to high temperatures for the synthesis of pigments and the high cost of their production.

The possibilities of obtaining pigments in the MgO-AL ₂ O ₃ -Cr ₂ O ₃ -SiO _{2 system} by substituting in equimolecular amounts of AL ₂ O ₃ for Cr ₂ O ₃ (Pyrkov V.P., Cherepanina L.I., Denisov A. N., Vizir L.A., Soldatova G.M. Ceramic Pigments of the Cordierite Type / Glass and Ceramics. 1981. - No. 5. - p.22-23). The starting raw materials were oxides MgO, AL ₂ O ₃ , Cr ₂ O ₃ , SiO ₂ . The pigments were fired in a neutral or slightly oxidizing environment at a temperature of 1320 ° C. The mineralizer was B ₂ O ₃ in an amount of 2% of the estimated weight of the pigments. After firing, the pigments have the properties of alexandrite: in daylight, their color is green or gray, with electric - pink and gray-green. X-ray phase analysis showed that the pigments of the MgO-AL ₂ O ₃ -Cr ₂ O ₃ -SiO _{2 system} are cordierite-spinel. The disadvantage of pigments is the use of pure chemicals as raw materials, high temperature synthesis of pigments.

Known are manganese-containing ceramic cordierite pigments synthesized by sequential equimolecular substitution of MgO in the composition of cordierite by MnO (Cherepanina L.I., Pyrkov V.P., Glebycheva A.I., Vizir L.A., Denisov A.N. Manganese-containing pigments cordierite type. / Glass and Ceramics. 1985. - No. 6. - p.22-23). As starting materials, oxides MgO, AL ₂ O ₃ , MnO ₂ , SiO _{2 were used} . The temperature of the firing of pigments 1300-1320 ° C. The color of pigments is dominated by pastel colors from pinkish-beige to beige with a brown tint. The lack of pigments can be considered a high synthesis temperature due to the absence of a mineralizer in their composition and color instability at different concentrations of MnO ₂ in the charge.

The prototype of the invention are cordierite-based pigments in which MgO was successively replaced by CoO in equimolecular amounts (Cherepanina L.I., Pyrkov V.P., Vizir L.A., Denisov A.N. Ceramic pigments of cordierite type MgO-CoO system -Al ₂ O ₂ -SiO _2. / Glass and Ceramics. 1978. - No. 12. - p. 27-28). The starting materials were oxides MgO, AL ₂ O ₃ , SiO ₂ . CoO was introduced using Co ₂ O ₃ , Co (NO ₃ ) ₂ · 6H ₂ O and CoCL ₂ · 6H2O. As a mineralizer used In ₂ About ₃ in the amount of 2% of the estimated mass of pigments. Firing was carried out at a temperature of 1320 ° C. The crystalline phase of all synthesized pigments is represented by cordierite (up to 40%), mullite, spinel, cristobalite. A significant effect of the mineralizer on the formation of cordierite has been established.

The disadvantage of this prototype is the low content of cordierite phase and a high firing temperature when used as a mineralizer In ₂ About ₃ , which has an intensifying effect on the synthesis through the formation of a liquid phase.

The objective of the invention is to obtain a blue ceramic pigment with a cordierite structure based on talc.

The problem is solved by compiling a mixture on the basis of talc with the addition of oxides Al ₂ O ₃ , SiO ₂ , CoO, as well as using a topaz concentrate from the Kopna deposit as a mineralizer (the chemical composition is presented in Table 1), followed by roasting and grinding the mixture. The mixture to obtain a ceramic pigment contains talc, Al ₂ O ₃ , SiO ₂ , CoO, and also contains topaz concentrate in the following ingredients, wt.%:

Talc 41.0-42.9 Al ₂ About ₃ 23.0-30.8 SiO ₂ 23.1-23.7 Soo 2.1-8.4 Topaz Concentrate 2.0-3.0

The temperature of the synthesis of the pigment is 1100-1200 ° C, it is recommended for use in underglaze and overglaze ceramic paints, as well as for coloring ceramic masses and glazes.

The coloring CoO oxide is introduced into the composition of the mixture in order to obtain a blue color of the pigment. A quantity of CoO of less than 2.1 wt.% Is not enough to provide the desired color, and an increase in the content of this chromophore of more than 8.4 wt.% Is impractical because it does not lead to a visible improvement in color.

Temperatures below 1100 ° C do not lead to the formation of a sufficient amount of cordierite phase and ensure a stable pigment color, and raising the firing temperature above 1200 ° C is not economically feasible, since it does not improve the color properties of the pigment. Exposure at a maximum temperature of at least 0.5 hours contributes to the final completion of phase formation processes of the crystalline structure of the pigment.

A content of topaz concentrate of less than 2 wt.% Is not enough to provide a mineralizing effect on the synthesis of pigments, and with the introduction of topaz more than 3 wt.% It is involved in the synthesis process not as a mineralizer, but as a component of the charge.

Pigment Production Example

The components of the mixture, wt.%: Onotskiy talc (chemical composition is presented in table 1) - 42.2, AL ₂ О ₃ - 28.4, SiO ₂ - 23.3, CoO - 4.1, topaz concentrate - 2.0 is mixed wet, dried at a temperature of 100 ° С , then fired at a temperature of 1150 ° C. After firing, the pigment is crushed before passing through a sieve of 10,000 holes / cm. The pigment compositions are shown in table 2.

The presented pigment compositions have the following physicochemical properties: the color of the pigment is blue, the dominant wavelength is 468-474 nm (Table 3), and the purity of the tone is 18-29%. The resulting pigments have a color from light blue to blue, can be used to obtain underglaze, overglaze paints (with the addition of flux), painted ceramic masses, glazes.

An advantage of the invention is the use of topaz concentrate as a mineralizer in an amount of 2-3% of the estimated mass of pigments. When heat treatment is rearranged topaz structure to form volatile fluorides which have a more significant impact on the synthesis of mineralizing cordierite than B ₂ O _3, due to its greater diffusion capacity.

Table 1.
The chemical composition of talc and topaz concentrate Raw materials Sod. mineral% The content of components, wt.% SiO ₂ Al ₂ About ₃ Cao MgO TiO ₂ Fe ₂ About ₃ F ^- OH ^- Topaz Concentrate Seats. Kopna 90.3 35.89 48.19 0.13 0.10 0.19 0.39 8.01 7.10 Onotsky Talc 99 62.28 0.56 0.4 31.14 next 0.50 - 5.12 Table 2.
The composition of the pigments, wt.% Pigment number Talc AL ₂ O ₃ SiO ₂ Soo Topaz Concentrate one 41.0 30.8 23.1 2.1 3.0 2 42.2 28.4 23.3 4.1 2.0 3 42.9 23.0 23.7 8.4 2.0 Table 3.
Color characteristics of pigments Pigment number Color coordinates Dominant wavelength λ _house , nm Purity of tone
R, % X Y one 0.22 0.18 468 eighteen 2 0.21 0.18 472 22 3 0.20 0.18 474 29th

Claims (1)

The mixture for the manufacture of blue ceramic pigment, including talc, Al ₂ O ₃ , SiO ₂ , CoO, characterized in that it as a mineralizer additionally contains topaz concentrate with the following ingredients, wt.%: Talc 41.0-42.9 Al ₂ O ₃ 23.0-30.8 SiO ₂ 23.1-23.7 Coo 2.1-8.4 Topaz Concentrate 2.0-3.0