RU2534875C1 - Mixture for producing tin sphene structured pink pigment - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to ceramic production, particularly to production of ceramic pigments. The mixture for producing pink pigment contains the following components in wt %: nepheline sludge 44.0-44.7, silicon oxide SiO₂ 15.4-15.6, tin oxide SnO₂ 38.6-39.2, chromium oxide Cr₂O₃ 0.5-2.0. Synthesis temperature of the pigment is 1150-1250°C. The pigment is used to produce underglaze and overglaze ceramic paints.

EFFECT: low synthesis temperature of the pigment, cheap ceramic pigments and recycling alumina wastes.

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Description

The scope of the invention is the production of ceramic products, pigments, paints. Currently, the construction industry requires decorative building materials, the production of which uses ceramic pigments, paints, decorative glazes. Usually, high-grade, expensive raw materials are used to produce pigments and paints. Mass construction requires inexpensive, affordable pigments based on unconventional raw materials - natural minerals and industrial waste.

Pink pigments are typically obtained in the CaO — SnO ₂ —SiO _{2 system} .

The pink pigment of optimal composition is known, mol: 0.4 CaO, 0.2 SnO ₂ , 0.4 SiO ₂ and 0.0023 Cr ₂ O ₃ . It was established that pink pigments have a crystalline structure similar to that of the natural mineral sphene CaTiSiO ₅ . The synthesis of this compound is carried out at a temperature of 1350 ° C from calcium stannate and calcium titanate (Filippova E.A., Bystrikov A.S. Study of chromium-containing ceramic pigments based on tin dioxide // Glass and ceramics. - 1973. - No. 2. - C . 26-27). The disadvantage of the invention is the high synthesis temperature, which leads to energy costs.

Also known is pink pigment composition, wt.%: Tin oxide - 45.6, chalk - 32.7, quartz sand - 14.6, chrompeak - 3.6, borax - 3.5. Chalk, quartz, tin oxide are thoroughly mixed, impregnated with a solution of chrompick, borax and calcined in an oxidizing medium at 1300 ° C. The pigment acquires the best color development upon repeated firing (Tumanov SG, Filippova EA. Study of the conditions for the formation and structure of pink pigments // Glass and Ceramics. - 1968. - No. 4. - S. 37-39). The disadvantage of this invention is also the high synthesis temperature and the need for additional firing (prototype).

The objective of the invention is to obtain a ceramic ceramic pigment with the structure of the Sn-sphene, improving the consumer properties of the pigments due to their cheapening.

The problem is solved as follows. In accordance with the prototype, the mixture for producing a ceramic ceramic pigment includes calcium-containing silicate raw materials, silicon oxide, tin oxide and a coloring substance chromium oxide Cr ₂ O ₃ . As a calcium-containing silicate raw material, alumina production waste - nepheline sludge is introduced into the charge. To ensure a stoichiometric composition of the sphene CaO · SnO ₂ · SiO _2, silicon oxides SiO ₂ and tin SnO ₂ are introduced. Moreover, these components are taken in the following ratio, wt.%:

nepheline sludge 44.0-44.7;

silicon oxide SiO ₂ 15.4-15.6;

tin oxide SnO ₂ 38.6-39.2;

chromium oxide Cr ₂ O ₃ 0.5-2.

This is followed by firing the mixture at a temperature of 1150-1200 ° C and grinding. Pigment is recommended for ceramic paints, staining of ceramic materials and glazes.

Coloring oxide Cr ₂ O ₃ is introduced into the pigment to obtain a pink color. The amount of introduced Cr ₂ O ₃ less than 0.5 wt.% Is not enough to obtain the desired color shade, and the introduction of this chromophore more than 2 wt.% Does not improve the color.

Firing at temperatures below 1150 ° C does not lead to the formation of a sufficient amount of the crystalline phase of tin sphene and ensuring a stable pigment color, and increasing the firing temperature above 1200 ° C does not contribute to improving the color properties of the pigment. Exposure at a maximum temperature of at least 0.5 hours allows you to finally complete the phase formation of the pigment crystal structure and color formation.

An advantage of the invention is the use of inexpensive raw materials - spent nepheline sludge, which contains in addition to the oxides CaO and SiO _{2 a} coloring oxide Fe ₂ O ₃ , which contributes to a more saturated pigment color.

Table 1 shows the chemical composition of nepheline sludge.

Table 2 shows the charge composition of the pigments.

Table 3 presents the color characteristics of the pigments.

Pigment Production Example

The components of the mixture, wt.%: Nepheline sludge, crushed to a residue on sieve No. 0063 no more than 2% - 44.5, silicon oxide SiO ₂ in the form of anhydrous silicic acid - 15.5, tin oxide SnO ₂ in the form of oxide - 39.0, chromium oxide Cr ₂ O ₃ in the form of oxide is 1.0, mixed wet, dried at a temperature of 100 ° C and fired at a temperature of 1200 ° C. After firing, the pigment is crushed to a residue on sieve No. 0063 of not more than 0.2%. The pigment compositions are shown in table 2.

The presented pigment compositions have the following physicochemical properties: the color of the pigment is pink, the additional wavelength is 497-499 nm, and the purity of the tone is 11-21%. The color characteristics of the pigments are shown in table 3. The obtained pigments can be used to obtain underglaze, overglaze paints (with the addition of flux), painted ceramic masses, glazes.

Table 1 Type of nepheline sludge The content of oxides, wt.% SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Na ₂ O K ₂ O Δm _prk Nepheline sludge from Achinsk Alumina Refinery 29.12 3.67 4,55 53.20 1.45 2.16 0.90 4.96

table 2 Pigment no. The composition of the pigments, wt.% Nepheline sludge SiO ₂ Sno ₂ Cr ₂ O ₃ one 44.7 39.2 15.6 0.5 2 44.5 39.0 15.5 1.0 3 44.0 38.6 15.4 2.0

Table 3 Pigment no. Color coordinates λ *, nm Tone purity p,% x y one 0.38 0.41 497 eleven 2 0.39 0.30 498 fifteen 3 0.41 0.29 499 21 λ * - additional wavelength

Claims (1)

A mixture for producing a pink pigment with a tin sphene structure, including silicon oxide SiO ₂ , tin oxide SnO ₂ and a coloring material, chromium oxide Cr ₂ O ₃ , characterized in that calcium-containing silicate feedstock, nepheline sludge, is additionally introduced into the mixture to obtain a stoichiometric composition of sphene while these components are taken in the following ratio, wt.%:
nepheline sludge 44.0-44.7, silicon oxide SiO ₂ 15.4-15.6, tin oxide SnO ₂ 38.6-39.2, chromium oxide Cr ₂ O ₃ 0.5-2.0.