RU2478590C1 - Slag fluxing agent - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of ceramic articles and can be used in making ceramic bricks as a fluxing component. The slag fluxing agent for coarse-grained ceramic mixtures contains barium carbonate, steel-smelting slag from the Rostov Electrometallurgical Plant and aluminium salt slag from the Alcoa Metallurg Rus plant, which are characterised by the following chemical composition, wt %: steel-smelting slag - SiO₂ - 40.48; Fe₂O₃ - 4.43; Al₂O₃ - 1.00; TiO₂ - 0.94; CaO - 44.80; MgO - 3.80; Na₂O - 0.61; loss on ignition - 3.70; aluminium salt slag - Al₂O₃ - 26.80; SiO₂ - 8.62; MgO - 21.04; KCl+NaCl - 38.21; other oxides - 0.31; Al - 3.42; loss on ignition - 1.60, with the following ratio of components, wt %: steel-smelting slag - 70-80; aluminium salt slag - 19.5-30; barium carbonate - 0-0.5.

EFFECT: high strength and frost resistance, reduced air shrinkage and water absorption of articles.

1 ex, 1 tbl, 1 dwg

Description

The invention relates to the production of ceramic products and can be used as a fluxing component in the technology of manufacturing ceramic bricks.

The known composition of glass-melt for ceramic masses of the following chemical composition, wt.%: SiO ₂ - 51.50-53.50; Fe ₂ O ₃ - 4.12-4.28; Al ₂ O ₃ - 11.51-11.97; TiO ₂ 0.45-0.47; CaO 11.85-12.30; MgO - 2.72-2.82; Na ₂ O - 13.03-16.26; K ₂ O - 1.57-1.63 [copyright certificate No. 1715722, publ. 02/29/92]. The disadvantage of this composition is the cooking of the raw material mixture at a high temperature of 1280 ° C, followed by grinding in a ball mill to a residue on sieve No. 0063 of 3-4%. These operations significantly increase the cost of flux.

As a prototype can serve as a melt, consisting of the following components, wt.%: Quartz sand - 19-36, soda ash - 31-42, cupola slag - 22-50, borax (in the form of additives over 100%) - 2-5 (patent No. 2087441, publ. 08/20/1997). The disadvantage of the prototype is the energy intensity of the process of cooking frits from these components, which is carried out at a temperature of 1450-1500 ° C, and the need for subsequent fine grinding.

The objective of the invention is the development of a composition of inexpensive and effective flux for the manufacture of high-quality ceramic materials, such as face and ordinary ceramic bricks, using waste from the metallurgical industry.

EFFECT: reduction of resource and energy intensity of firing of products of building ceramics by intensification of sintering and phase formation processes using effective flux obtained on the basis of technogenic raw materials. When designing the composition of slag melt, we took into account the comprehensive elimination of the negative properties of low-grade clay raw materials and the production of ceramic products, such as bricks, with a pronounced yellow (beige) color of the crock and with high strength characteristics, increased frost resistance and low air shrinkage and water absorption.

The essence of the invention lies in the fact that slag melt contains metallurgical waste - steelmaking slag from the Rostov Electrometallurgical Plant and aluminum salt slag from the Alcoa Metallurg Rus plant, which are characterized by the following chemical compositions, wt.%: Steelmaking slag - SiO ₂ - 40.48; Fe ₂ O ₃ - 4.43; Al ₂ O ₃ - 1.00; TiO ₂ 0.94; CaO - 44.80; MgO - 3.80; Na ₂ O - 0.61; p.p.p. - 3.70; aluminum salt slag - Al ₂ O ₃ - 26.80; SiO ₂ - 8.62; MgO - 21.04; KCl + NaCl - 38.21; other oxides - 0.31; Al - 3.42%; p.p.p. - 1.60, and also additionally includes barium carbonate in the following ratio of components, wt.%: Steelmaking slag - 70-80, aluminum salt slag - 19.5-30, barium carbonate - 0-0.5.

Depending on the type of product (ordinary or front ceramic), the percentage of components may vary.

The sequence of operations for the manufacture of slag flux is shown in the figure. Steelmaking and aluminum salt slags, barium carbonate are stored in bins. Next, steelmaking slag undergoes electromagnetic separation, which allows you to extract metal inclusions from it. Aluminum salt and steel slag are screened to produce grains of less than 0.14 mm. Larger grains of slag are subjected to additional fine grinding, after which, with the help of weighing batchers, the components of the melt are dosed in accordance with the established ratio. After that, the components are mixed to achieve a high degree of homogenization of the composition of the slag flux. The finished product enters the stock hopper.

Due to the fact that the slags that are part of the melt are characterized by the phase composition formed as a result of high temperature treatment, the presence of a high content of alkali and alkaline earth metal chlorides and fluorides and the predominance of particle size less than 0.14 mm in the particle size distribution, there is no need to cook it at elevated temperature and subsequent crushing. This achieves resource and energy conservation. After mixing the components, slag melt is introduced into the ceramic mass in the form of a powder.

The absence of energy-intensive costs for firing the raw materials of which fusion consists, and the use of industrial waste significantly reduces the cost of building ceramics technology. The use of the proposed slag flux allows you to implement the aspects of resource and energy conservation in the production of high-quality products. Along with this, a solution to the urgent environmental problem - the recycling of metallurgical slag.

The high content in the chemical composition of the steelmaking slag CaO promotes active clarification of the shard due to solid-phase firing reactions occurring with the formation of new light-colored phases such as anorthite, wollastonite, pyroxene, which, as a result of isomorphic substitutions, include iron ions according to the scheme Fe ⁺³ ↔Al ⁺³ ; calcium fluoride, contained as an impurity, intensifies the formation of a liquid phase. In this case, the coloring effect of the iron-containing phases is neutralized, giving the ceramic shard a traditional brick color.

Chlorides of alkali metals, which are part of aluminum salt slag, have a mineralizing effect on the sintering processes of a ceramic crock, significantly increasing the content of glass phase in the calcined product. Barium carbonate is added to the composition of slag melt only when used in face brick technology to eliminate efflorescence due to the high content of sulfate compounds in low-grade clay raw materials.

Examples

To identify the fluxing effect of slag melt and its effectiveness in coarse-grained ceramic masses, front and ordinary ceramic bricks were made.

Loam of the Vlasov deposit and a mixture of refractory clays from the Vladimirovsk deposit VKS-2 are used as clay raw materials. The sand of the Vladimirovskoye field was used as an abrasive agent in the base compositions.

The compositions of slag flux were used, are shown in table 1.

Table 1 Compositions of slag flux Component The content of the component for the compositions,% by weight SHP-R * SHP-L ** Steel Slag 70 80 Aluminum Salt Slag thirty 19.5 Barium carbonate - 0.5 * - ШП-Р was used for the manufacture of ordinary bricks; ** - ШП-Л was used for the manufacture of face bricks.

To obtain products from the developed ceramic mass, the traditional brick production technology was used. The ceramic mass was prepared in a plastic way. Molding was carried out by the plastic method with molding moisture of 22%. The molded brick was dried to a residual moisture content of 6%. The dried brick without the use of slag melt (compositions No. 1.0 and 2.0 according to table 2) was fired at a temperature of 1000 ° C, using ШП-Р and ШП-Л - at 950 ° С.

Table 2 shows the composition of ceramic masses as examples, and table 3 shows the physical, mechanical, operational, and aesthetic and consumer properties of ceramic bricks obtained from these masses.

table 2 The compositions of ceramic masses Component The content of the component for the compositions,% by weight 1.0 1.1 2.0 2.1 Loam Vlasovsky 85 85 68 68 Blend VKS-2 - - 12 12 Sand Vladimirovsky fifteen - twenty - SHP-R - fifteen - - SHP-L - - - twenty

Table 3 Physico-mechanical, operational and aesthetic and consumer properties of bricks Indicator Values for formulations 1.0 1.1 2.0 2.1 Water absorption,% 16,0 10.8 15,2 10.1 Tensile Strength, MPa: - for compression 15.3 20.8 19.3 25,4 - on a bend 2.6 6.5 3,5 9.1 Frost resistance cycle 28 46 36 60 Shard color red pink red yellow

The effectiveness of the proposed slag flux when used in the production of ceramic bricks is confirmed by the data in Table 3. For compositions using ШП-Р water absorption decreases by 3.2%, mechanical compressive strength increases by 36%, bending - by 2.5 times, frost resistance increases by 18 cycles compared to the base case (No. 1.0). For compositions using SHP-L, water absorption is reduced by 3.1%, mechanical compressive strength is increased by 32%, bending - by 2.6 times, frost resistance is increased by 24 cycles compared to the base case (No. 2.0). In this case, the firing temperature of products with slag melt is reduced by 50 ° C relative to the firing temperature of the base compounds. Thus, the introduction of slag flux into ceramic masses for the production of both ordinary and face bricks makes it possible to intensify the sintering process of the ceramic matrix at a lower temperature, which ultimately leads to a decrease in the energy intensity of firing products and the cost of the finished product and its quality.

Claims (1)

Slag melt for coarse-grained ceramic masses, including metallurgical waste, characterized in that the waste contains steelmaking slag from the Rostov Electrometallurgical Plant and aluminum salt slag from the Alcoa Metallurg Rus plant, which are characterized by the following chemical compositions, wt.%: Steelmaking slag - SiO ₂ 40 , 48; Fe ₂ O ₃ 4.43; Al ₂ O ₃ 1.00; TiO ₂ 0.94; CaO 44.80; MgO 3.80; Na ₂ O 0.61; p.p.p. 3.70; aluminum salt slag - Al ₂ O ₃ 26.80; SiO ₂ 8.62; MgO 21.04; KCl + NaCl 38.21; other oxides 0.31; Al 3.42; p.p.p. 1.60, and also additionally includes barium carbonate in the following ratio of components, wt.%:
Steel Slag 70-80 Aluminum Salt Slag 19.5-30 Barium carbonate 0-0.5

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