RU2266878C2 - Method of manufacture of building light-yellow ceramics and its composition - Google Patents

Abstract

FIELD: manufacture of ceramic materials on base of clay materials; manufacture of facing building bricks and facing tiles from red-burning low-melting clays.

SUBSTANCE: proposed method includes preparation of mineral additive, mixing this additive with clay, plastic molding of articles and burning. Additive is prepared according to slip process by grinding the clarifying component of additive with clay in the amount of 8-10% of mass of clarifying component; grinding is performed in ball mill to residue on sieve 0088 not exceeding 2-3%; then, hardening finely-dispersed component of additive is introduced into suspension. Slip thus obtained has density of 1.70-1.72 g/cm³. Slip is mixed with clay; part of clay is preliminarily dried to moisture content of 6-8%. Ceramic mass thus obtained is subjected to homogenization and aging for at least 24 h; burning is performed at temperature of 1020-1030°C. Marl at size of particles lesser than 2 mm and content of limestone no less than 75 mass-% is used as clarifying component and wollastonite concentrate at size of particles lesser than 0.063 mm and content of wollastonite no less than 80 mass-% is used as hardening finely-dispersed component.

EFFECT: enhanced mechanical strength, corrosion resistance and improved decorative properties of articles.

3 cl, 3 tbl, 1 ex

Description

The invention relates to the production of ceramic materials based on clay raw materials and can be used, for example, for the manufacture of facing ceramic bricks, tiles, ceramic tiles light yellow in color from red-burning low-melting clays.

A known method of obtaining a facial light-colored (from cream to yellow) ceramic brick by combining red-baked low-melting clay and light-baked refractory (or refractory) clay / Alperovich I.A. Clay brick production. - Overview of VNIIESM, M., 1978, p. 4-7, p. 14-17 /.

The disadvantage of this method is the difficulty of achieving in production conditions a high homogeneity of the ceramic mass, consisting of a mixture of plastic components with a large difference in properties. In addition, the real production of building ceramics is not always able to operate heterogeneous clay raw materials.

A known method of manufacturing a face brick from red-burning clay raw materials by mixing low-melting clay with 15-50 wt.% Dolomite (carbonate additive), molding, drying and firing / Lundina MG Additives in the mixture in the production of ceramic wall materials. Overview information VNIIESM, M., 1974, p. 70-71 /.

A known method of producing facial bricks of light tones from ordinary red-baked fusible clays by volumetric staining of the composition mass (vol.%): Cambrian clay - 45, quartz sand - 20, finely divided chalk - 35% / Alperovich I.A. New in the technology of ceramic facing brick volumetric painting. Building Materials, 1993, No. 7, p. 5-9 /.

The essence of the technology of bulk dyeing of the mass due to the introduction of carbonate additives (limestone, chalk, dolomite flour) in these methods consists in fine grinding the coloring (clarifying) additives in a ball or jet mill in a dry way to a fraction passing through a 0088 sieve in an amount of not less than 90% , and thorough mixing of the obtained powder with plastic clay mass on effective clay processing equipment / Alperovich I.A., Smirnov A.V. Front ceramic volumetric brick in modern architecture. Building Materials, 1990, No. 12, p. 4-6 /.

The disadvantage of these methods is the difficulty of achieving a homogeneous state under production conditions when a powdery finely dispersed additive is mixed with clay in a dough-like state due to a sharp discrepancy between the components in terms of humidity and plastic properties, which causes a constant danger of mixing heterogeneity and, as a consequence, incompleteness of the calcium oxide binding reaction, which sharply negatively affects on the operational properties of the product, leading in some cases even to its destruction and due to the hydration of free (unreacted) calcium oxide during storage or during operation of the product in building structures.

Closest to the proposed one is the composition and method of making face bricks of light yellow and cream colors from red-burning clays by joint dry grinding of 15-90 wt.% Low-melting clay with a carbonate additive in a ratio of 1: 1-3: 1 to a fineness of grinding with a residue of sieve 006 no more than 10% and subsequent mixing of finely dispersed clay carbonate powder with the remaining clay / Rybiev I.A., Seregin A.A., Skrylnikov D.K. A method of manufacturing a front brick. A.S. 874710, publ. 10.23.81, BI No. 39 /. The disadvantage of this method is, as in previous cases, the need for thorough homogenization of a mixture of moistened clay and dry, finely ground clay-carbonate additives.

The task of the invention is to increase the mechanical strength, frost resistance and decorative properties of products.

The invention consists in activating the processes of structure formation and color formation of a ceramic mass based on low-melting, red-burning clay in combination with a mineral additive, which is ensured by a set of operations consisting in the fact that the mineral additive is prepared by the slip method by grinding the clarifying component of the additive together with 8-10% clay from the mass of the clarifying component of the additive in a ball mill to the residue on a 0088 sieve of not more than 2-3%, followed by the introduction of a reinforcing thin code into the suspension component of the additive, then the resulting slip with a density of 1.70-1.72 g / cm ³ is mixed with clay, part of which is pre-dried to a moisture content of 6-8%, the ceramic mass is homogenized and aged for at least 24 hours.

As a clarifying component, a marl with a particle size of less than 2 mm with a limestone content of at least 75% is used as a clarifying component, and a finely dispersed wollastonite concentrate with a particle size of less than 0.063 mm with a wollastonite content of at least 80% is used as a strengthening component with a ratio of ceramic mass of the composition (wt.%): fusible clay - 50-60, marl - 30-35, wollastonite concentrate - 10-15.

The preparation of the mineral additive by the slip method consists in finely grinding the marl with the addition of clay in an amount of 8-10% of the mass of marl in a ball mill by wet method to a residue on sieve 0088 of not more than 2-3%, followed by mixing the suspension with finely dispersed wollastonite concentrate. The introduction of clay when grinding the carbonate component in an amount of 8-10% by weight of marl is necessary to increase the sedimentation stability of the suspension. To regulate the viscosity of the slip, a complex diluent is used in an amount of 0.3% by weight of clay in the solid part of the slip, which is a mixture of water glass with a density of 1.45 g / cm ³ and soda ash in a ratio of 1: 2.

The addition of marl with a limestone content of at least 75% performs the function of a color-forming (clarifying) component in the composition of a ceramic mass based on red-burning clay.

The addition of wollastonite concentrate with a wollastonite content of at least 80% is used as a strengthening component of the ceramic mass and is an enrichment product of wollastonite rocks with a particle size of less than 0.063 mm.

The choice of marly rock as a color-forming mineral additive is determined by the peculiarities of the behavior of calcium carbonate in combination with red-burning clays during firing, which consist in clarifying the ceramic mass due to the synthesis of new iron-containing compounds that bind coloring iron oxide to minerals with a colorless or low-intensity color.

The use of marl supplements with a calcite content of at least 75% in amounts of less than 30% does not provide the required light yellow color, causing cream and orange shades of the product. An increase in the amount of marl additive by more than 35% leads to an increase in the porosity of the ceramic crock and the need to increase the firing temperature to intensify the sintering process.

The choice of wollastonite concentrate as a reinforcing component in the case of using limestone as a bleaching additive in ceramic brick technology is due to the need to increase the strength of the shard due to the reinforcement of the ceramic matrix. In addition, the use of wollastonite allows you to solve a set of issues to improve the quality of the masses, semi-finished products and, ultimately, finished products. In particular, to improve the drying properties of raw materials, reduce shrinkage, increase the strength and frost resistance of the finished product.

The use of additives of wollastonite concentrate in amounts of less than 10% does not ensure the achievement of the required level of strength properties. The introduction of additives of more than 15% leads to a deterioration in the plastic and molding properties of clay-carbonate masses due to an increase in the proportion of non-plastic components.

Grinding marl additives to a particle size of less than 0.088 mm by the wet method is necessary to create a homogeneous fine-grained mass that is evenly distributed throughout the clay mass and has a developed contact surface with clay particles, which ensures the maximum completeness of the process of binding of iron oxide into colorless compounds.

The aging of the mass in the charge reservoir for at least 24 hours is necessary to ensure the completeness of the mass transfer processes in the system "wet clay - dry clay - calcareous slip", consisting in the redistribution of part of the free water introduced with flooded clay rock and slip into a bound state during transition it into hydration shells as dry clay swells.

Example:

Products according to the claimed method are made according to the generally accepted technology for the production of ceramic bricks by plastic molding with firing at a temperature of 1020-1030 ° C.

As clay raw materials for ceramic bricks, fusible, red-burning clay of the Voroninsky deposit of the Tomsk region is used.

As a carbonate raw material as one of the components of the mineral additive, marl of the Kamensky deposit of the Tomsk region with a content of limestone proper of at least 75% is used.

Wollastonite concentrate is used as a reinforcing additive as an enrichment product of wollastonite-containing rocks of the Sinyukhinsky deposit in the Altai Territory, which is wollastonite-diopside raw materials (64.8% wollastonite and 26.6% diopside) with minor impurities of quartz (3.8%), calcite (3, 5%) and magnesite (1.3%).

The expediency of choosing wollastonite concentrate is determined by the needle habit of its particles with a needle length of 20 to 200 μm and a thickness of 2 to 10 μm, creating a spatial framework of mutually intertwined needles in the ceramic matrix and thereby giving the ceramic product dimensional stability and high strength. Annealing of wollastonite rocks at 1000 ° С has practically no effect on changes in the shape and geometric parameters of particles, which indicates the thermal stability of wollastonite up to 1000 ° С.

The characteristics of the raw materials in chemical composition are given in table 1.

Since one of the indispensable conditions of volumetric staining technology is the need for fine grinding of coloring additives in a ball or jet mill to a fraction passing through a 0088 sieve in an amount of not less than 97-98%, the marl rock is subjected to primary crushing in a jaw crusher before passing through a sieve with a mesh size of 2 mm and subsequent fine grinding in a ball mill by a wet method with the addition of clay in the amount of 8-10% of the solid hour as a stabilizer to prevent separation of the suspension ty slip. The additive is crushed to a residue on sieve No. 0088 of no more than 2-3%.

The grinding product is a slip with a density of 1.70-1.72 g / cm ³ . To ensure the fluid state of the carbonate suspension, a complex fluidizing additive is introduced in an amount of 0.3% by weight of clay in the solid part of the slip, which is a mixture of water glass with a density of 1.45 g / cm ³ and soda ash in a ratio of 1: 2.

Since the technological additive for uniform distribution over the entire volume of the ceramic mass is used in a slip-like state, for the production of plastic ceramic mass with molding moisture of 19-21% from clay with career moisture, which is often more than 20-22%, the introduction of moisturizing raw materials is necessary. Therefore, the preparation of the clay component of the ceramic mass involves drying part of the clay in a drying drum to a moisture content of 6-8%, the other necessary part of the clay is used with storage (quarry) humidity.

Dosage of all components is carried out by weight. Component compositions of ceramic masses are given in table.2.

Raw brick is molded in the traditional way. Then the raw material is evenly dried in dryers to a moisture content of 4-6%.

The semi-finished product is fired at a temperature of 1020-1030 ° C for 36 hours with exposure at a final temperature of at least 2 hours. Lowering the firing temperature less than 1000 ° C does not ensure the completeness of the sintering process and the formation of the structure of ceramic bricks, firing at temperatures above 1020-1030 ° C is impractical for economic reasons due to the increase in energy costs. The properties of the calcined products are given in table.3.

The slip method of preparing and introducing a mineral additive ensures a homogeneous distribution of the additive components throughout the volume of the ceramic mass and, as a result, the completeness of the reactions of synthesis of iron-containing compounds with a colorless or low-intensity color, ensuring a uniform light yellow color of the products. The use of wollastonite concentrate in the additive ensures the creation of a spatial framework of mutually intertwined needles in the ceramic matrix and thereby gives the ceramic product dimensional stability, high strength and frost resistance.

A method of manufacturing building ceramics light yellow and its composition

Table 1
The chemical composition of raw materials Clay The content of oxides,% wt SiO ₂ Al ₂ About ₃ Fe ₂ About ₃ CaO MgO R ₂ O Δm _prk Clay Voroninsky 65.84 14.28 4.76 4.20 2.45 1.51 6.96 Mergel Kamensky 14.36 4.46 0.73 43,44 1.06 - 35.85 Wollastonite Concentrate 50.11 1,04 1.81 46.09 0.48 0.40 - table 2
The composition of ceramic masses Components The content of components in the compositions, wt.% 1 2 3 Outlawing compositions A B IN Clay Voroninsky 60 55 fifty 70 65 40 Mergel Kamensky thirty thirty 35 25 27.5 40 Wollastonite Concentrate 10 fifteen fifteen 5 7.5 twenty

A method of manufacturing building ceramics light yellow and its composition

Table 3
Ceramic properties of products Property metrics Prototype Compositions 1 2 3 Outlawing compositions A B IN Firing temperature, ° С 1020 1020 1020 1020 1020 1020 1020 Water absorption,% 11.5-12.2 13.5 13.9 13.9 12.1 12.3 14.3 Compressive strength, σ _{compression channel,} MPa 22.4-26.6 35.5 36.1 36.3 30.1 30.5 37.3 Frost resistance cycles 35 More than 35 More than 35 More than 35 More than 35 More than 35 More than 35 Shard color Light cream Light yellow Light yellow Light yellow cream Cream Light yellow

Claims (2)

1. A method of manufacturing building ceramics of light yellow color based on fusible red-burning clay, comprising preparing a mineral additive, mixing the additive with clay, plastic molding of products and firing, characterized in that the additive is prepared according to the slip method by grinding the clarifying component of the additive together with 8- 10% clay from the mass of the clarifying component in the ball mill to the residue on a 0088 sieve of not more than 2-3%, followed by the introduction of a hardening finely dispersed component of the additive into the suspension, We eat the resulting slip with a density of 1.70-1.72 g / cm ³ mixed with clay, part of which is pre-dried to a moisture content of 6-8%, the resulting ceramic mass is homogenized and aged for at least 24 hours, and fired at a temperature of 1020- 1030 ° C, while marl with a particle size of less than 2 mm with a limestone content of at least 75 wt.% Is used as a clarifying component, and wollastonite concentrate with a particle size of less than 0.063 mm with a wollastonite content of at least 80 wt. Is used as a hardening finely dispersed component .%. 2. The composition for the manufacture of building ceramics of light yellow color based on fusible red-burning clay by the method according to claim 1, containing fusible red-burning clay and an additive when they are contained in the ceramic mass, providing the following ratio of components, wt.%: Indicated clay 50-60 The specified marl 30-35 Indicated wollastonite 10-15