RU2191168C1 - Raw material mixture for preparing wall ceramic articles - Google Patents

Abstract

FIELD: production of right-side ceramic materials. SUBSTANCE: raw material mixture includes fly ash from burning of brown coal, microsilica from production of crystal silicon, 5-% emulsion of tall oil pitch in 2-% aqueous solution of Na₂CO₃ at the following ratio of components, mas.%: fly ash, 24.4-32.0; microsilica, 56.9-48.0; emulsion of tall oil pitch, 18.7-20.0. EFFECT: reduced water absorption, and increased reliability and resistance to cold. 2 tbl, 1 ex _

Description

 The invention relates to the production of building materials and can be used for the manufacture of fired facial ceramic products.

Closest to the proposed raw material mixture is a raw material mixture comprising 15-80 wt.% Silica fume produced by crystalline silicon and 20-85 wt.% High calcium ash from the burning of brown coal. The components are mixed in a dry state, moistened to 16%, molded by semi-dry pressing and calcined at a temperature of 1000 ^o C [RF Patent 2086517 C 04 V 35/14, 35/16].

 The disadvantage of this mixture is the relatively low compressive strength and frost resistance of the calcined products, as well as increased water absorption, which does not allow to make wall facing products from such a mixture.

 EFFECT: increased frost resistance and strength, reduced water absorption of the material.

The technical result is achieved by the fact that as the raw materials are used fly ash from burning brown coal, silica fume production of crystalline silicon and a 5% emulsion of tall pitch in a 2% aqueous solution of Na ₂ CO ₃ in the following ratio, wt.%:
Ash - 24.4-32.0
Silica fume - 56.9-48.0
Tall pitch emulsion - 18.7-20.0
The advantages of the proposed mixture are achieved by the inclusion in its composition of emulsion tall pitch. The latter is obtained as a result of self-emulsification of the pitch when it is heated in an aqueous solution of Na ₂ CO ₃ . Soda ash not only makes it possible to obtain tall pitch emulsion at minimal cost, but it is also a mineralizing additive that accelerates phase formation during firing. This contributes to the complete binding of free calcium and magnesium oxides to crystalline neoplasms, which determines the increase in strength and frost resistance of products.

Silica fume produced by crystalline silicon of the Bratsk aluminum smelter is a fine waste characterized by a high content of amorphous silica. The chemical composition of silica fume (in wt.%):
SiO ₂ - 90-95
Al ₂ O ₃ - Up to 0.8
Fe ₂ O ₃ - Up to 0.8
CaO - Up to 1.6
MgO - Up to 1.2
SiC - Up to 5
From _general - Until 9
K ⁺ - Up to 0.25
Na ⁺ - Up to 0.06
P.P.P. - Up to 20
Fly ash from burning brown coal of the Kansk-Achinsk basin (Irsha-Borodinskoye, Nazarovskoye, Berezovskoye deposits) are high-calcium and contain (in wt.%):
SiO ₂ - 21-55
Al ₂ O ₃ - 4-11
Fe ₂ O ₃ - 6-16
CaO - 20-46
MgO - 3-6
K ₂ O - 0.2-1.5
Na ₂ O - 0.2-0.6
SO ₃ - 0.9-9
St. CaO - 3-13
Combustible impurities - Not more than 2-2.5
Tall pitch is the bottom residue from the distillation of tall oil. This wood chemical product is currently mainly incinerated. Tall pitch contains (in wt.%):
Neutral Substances - 24-38
Oxidized Substances - 12-29
Resin acids - 6-26
Fatty Acids - 28-41
The presence of fatty and resin acids in tall pitch allows the emulsion to be prepared by self-emulsification by partially saponifying the above ingredients with a solution of soda ash with the formation of sodium salts of fatty and resin acids, which are surfactants. At the molding stage, the emulsion of tall pitch provides an increase in the plasticity and cohesion of dispersed technogenic raw materials. During the drying process, the thermal polymerization of tall pitch leads to hardening of the dried raw material to 5.4 MPa. During the firing process, the mineralizing effect of soda in combination with the favorable effect of the gas phase formed during the burnout of the organic component of the emulsion leads to the complete binding of CaO and MgO fly ash to the neoplasms, resulting in an increase in the strength and frost resistance of the material, as well as a decrease in its water absorption.

 The technical and economic effect of the production of material on the basis of the proposed mixture is combined with an environmental effect, since the main components of the charge are large-capacity waste, currently not widely used.

Example
To prepare the raw material mixture, silica fume is used to produce crystalline silicon, fly ash from burning brown coal and tall pitch emulsion.

A tall pitch emulsion is prepared as follows: a 2 percent aqueous solution of an alkaline component, for example, Na ₂ CO _3, is gradually introduced into a pitch heated to 40-50 ^{° C.} Heating is carried out with constant stirring until a homogeneous emulsion is obtained. The concentration of tall pitch in the emulsion is 5 wt.%.

Silica fume and fly ash are mixed in a dry state, after which a tall pitch emulsion is introduced to obtain a mass of molding moisture. From the resulting mass, samples are molded by the plastic method at a pressure of 2.5 MPa. The molded raw material is dried at 100-110 ^o C to constant weight and calcined at 1000 ^o C. Specific examples of compositions, physico-mechanical properties and calcined products are given in table. 12.

Claims (1)

The raw material mixture for the manufacture of wall ceramic products, including fly ash from burning brown coal, silica fume production of crystalline silicon and a mixing liquid, characterized in that a 5% tall pitch emulsion in a 2% aqueous solution of Na ₂ CO _{3 is} used as a mixing liquid in the following ratio of components wt. %:
Fly ash - 24.4-32.0
Silica fume - 56.9-48.0
Tall pitch emulsion - 18.7-20.0,

Images