RU2484063C1 - Raw mix for manufacturing of ceramic thermal insulating building materials - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: raw mix contains the following components, wt %: argillites - 69.0-74.8; diopside-containing rock - 10-15; crushed glass - 9.5-10.5; building gypsum - 4.92-5.1; alumnium powder - 0.58-0.6; sodium hydroxide, 2H solution - 29.6-30.0% above 100%, of dry mixture, V/G - 0.42-0.45.

EFFECT: increased strength of porous items with preservation of their density and temperature of annealing.

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Description

The invention relates to the building materials industry and can be used for the production of heat-insulating ceramics.

Known raw mix, including in the composition of the components in the following ratio, wt.%: Loam 20-25; aluminum powder 0.06-0.10; ground lime 0.7-1.0; shale - waste from the processing of bitumen shale or waste 20-25; metallurgical carbonate-containing slag 22-23; superplasticizer based on sodium salts, polycondensation product of naphthalene sulfonic acid and C-3 formaldehyde 0.18-0.02; water - the rest (USSR Author Certificate No. 1678810 A1, priority date 04/27/1989, publication date 09/23/1991, authors G. Burlakov et al., RU).

A disadvantage of the known raw material mixture is the release of aggressive gases during the firing of ceramic mixtures using polymers, as well as the increased density of finished products - 640 kg / m ³ .

The closest in technical essence is the raw mix adopted as a prototype, consisting of a clay component - loam, a corrective additive - zeolite with a water-clay ratio W / G = 0.8-1.0, a binder, which simultaneously performs the role of an alkaline additive - finely ground lime and additives blowing agent - aluminum powder, in the following ratio of components, wt.%: loam - 83.3-75.4; zeolite 12.50-18.85; aluminum powder - 0.08-0.11; ground lime 4.12-5.64 (RF Patent No. 2281268 C2, priority date 04.11.2004, publication date 10.08.2006, authors Zavadsky V.F. et al., RU, prototype).

The disadvantage of the prototype is the low strength of the products at a density of 440-640 kg / m ³ after firing at a temperature of 950 ° C - 2-2.2 MPa, indicated in the abstract [Putro NB Porous porcelain building ceramics (composition, technology, properties): author. dis ... cand. tech. sciences / N.B. Putro. - Novosibirsk, 2004 - 24 p.].

The objective of the invention is to increase the strength of porous products while maintaining their firing temperature and density.

To solve this problem, the raw material mixture for the manufacture of ceramic heat-insulating building materials, including a clay component, a corrective additive, an alkaline additive, a binder and a blowing agent - aluminum powder, according to the invention, it contains mudstones as a clay component, and diopside-containing rock and cullet as a corrective additive , as an alkaline additive - 2 N. sodium hydroxide solution, as a binder - building gypsum, with a water-clay ratio of 0.42-0.45 and the following ratio of components, wt.%:

Mudstone 69.0-74.8 Diopside-containing rock 10-15 Cullet 9.5-10.5 Plaster of construction 4.92-5.1 Aluminum powder 0.58-0.6 Sodium hydroxide, 2N solution (in excess of 100%) 29.6-30.0%

To implement the invention in the raw material mixture, the following components were used.

Montenegrin mudstones (Khakassia) are used as clay rocks, the granulometric composition of which varies from coarse to dispersed with clay particles from 26.5 to 47.5%, sand - from 45 to 50%. The chemical composition of mudstones is in the following ranges, wt.%: SiO ₂ - 51.86-58.12; Al ₂ O ₃ - 15.7-20.35; Fe ₂ O ₃ - 5.57-6.01; CaO - 1.73-3.17; MgO - 2.21-1.66; Na ₂ O - 1.2-1.8; K ₂ O - 2.3-2.9, p.p.p. - 8.2-12. Mudstones are crushed, dried and milled before passing through a sieve with a mesh size of less than 0.16 mm.

As a corrective additive, diopside-containing rock and glass cullet are used from a mixture of window and container glass, crushed to a residue of not more than 5% on a sieve with a mesh size of 0.063 mm.

When fine-dispersed additives of diopside-containing rock and cullet are introduced into the clay suspension, the process of foaming is facilitated by the action of additives as cleaners, the process of gaining structural strength of foamed masses is accelerated, which helps to reduce the degree of sedimentation of the porous mixture after foaming and to reduce the average density of the products. In the process of firing products, the addition of diopside-containing rock, composed mainly of diopside (92-95%), exhibits the properties of a structure-forming additive that provides increased strength of the products while maintaining their high porosity, and the addition of cullet as a melt-forming component promotes low-temperature sintering of products.

Table 1 shows the chemical composition of the Montenegrin mudstones (Khakassia), diopside-containing rocks and cullet used in the raw mix.

PAP - 2 grade aluminum powder (GOST 5494-95) is used as a blowing agent for the porosity of the raw material mixture. The specific surface area of aluminum powder is 5500-6000 cm ² / g, the content of active aluminum in it is 87-98.5%.

Providing the alkaline environment of the mixture is achieved by changing the sodium hydroxide, which is introduced in the form of a 2N solution in excess of 100% of the dry mixture.

As a binder, which secures the porous structure of the mixture after foaming, gypsum gypsum grade G-6 is used, which meets the requirements of GOST 1308-81, the setting time of which is 3-11 minutes, the end - 7-15 minutes.

The manufacturing technology of the raw mix is carried out according to the following scheme.

Building gypsum with a standard fineness of grinding, finely ground diopside-containing rock and cullet are added to previously prepared mudstones and mixed in a dry state. Then, water heated to 50-60 ° C and in the required amount of 2 N are introduced into the mixture. sodium hydroxide solution, after which aluminum powder is added. Mixing is carried out until a uniform fluid mass is obtained. The obtained liquid-viscous mass is poured into the mold, filling its volume by 2/3 of the height to obtain samples and determine their properties. The process of porization and expansion of the mass lasts 30-40 minutes. Then the samples are dried at a temperature of 70-90 ° C for a duration of 10-12 hours. After drying, the molds are removed, and the products are fired for 8 hours at a temperature of 950 ° C.

The compositions of the inventive mixtures and prototype are shown in table 2.

table 2 Components Content, wt.% In the composition Prototype,% one 2 3 four 5 Mudstones 66.9 69.0 72,4 74.8 81.1 Diopside-containing rock 17 fifteen 12 10 5 Cullet eleven 10.5 10.0 9.5 8 Gypsum G-6 4,53 4.92 5.01 5.10 5.29 Sodium hydroxide, 2 N. 29.4 29.6 29.8 thirty 30,2 Aluminum powder 0.57 0.58 0.59 0.60 0.61 0.08-0.11 W / D 0.48 0.42 0.43 0.45 0.47 0.8-1.0 Loam 75.40-87.61 Zeolite rock 12.50-18.85 Ground lime 4.12-5.64

For example, to implement a technical solution - composition No. 2 of the mixture, crushed argillite in an amount of 69%, gypsum building grade G-6 - 4.92%, finely ground diopside-containing rock - 15% and finely ground cullet - 10.5% were mixed in the dry state for 5 minutes. Water heated to 50-60 ° C with a water-clay ratio of 0.42 and 2 N. a solution of sodium hydroxide in an amount of 29.6% was introduced into the mixture and stirred for 2 minutes, then 0.58% aluminum powder was added and mixed for another 2 minutes until a uniform fluid mass was obtained. Then the raw material mixture was poured into molds, filling at 2/3 of the height to obtain samples and their testing for mechanical strength and other properties. The process of porization and foaming lasted 35 minutes Next, the samples were dried at a temperature of 70 ° C for 10 hours, then they were calcined in a disassembled form for 8 hours at a temperature of 950 ° C. Finished samples were tested to determine their properties.

Physico-mechanical properties of products obtained from the compositions indicated in table 2 are shown in table 3.

Table 3 The properties Indicators for the composition Prototype one 2 3 four 5 Firing temperature, ° С 950 950 950 950 950 950 Density, kg / m ³ 600 550 500 440 560 440-650 Compressive strength, MPa 2.7 4.9 4.1 3,7 1.9 2.0-2.2

The results shown in table 3 show that the proposed compositions of the inventive raw mix have higher strength products at the same density than the known composition. From table 3 it is also seen that products from a mixture with a ratio of components different from the ratio of components in the proposed composition have lower strength and higher density (compositions No. 1 and No. 5).

Thus, the obtained raw material mixture of the optimal composition for the manufacture of ceramic heat-insulating building materials of increased strength at a density of 440-550 kg / m ³ .

Claims (1)

A raw material mixture for the manufacture of ceramic heat-insulating building materials, including a clay component, a corrective additive, an alkaline additive, an astringent and a blowing agent - aluminum powder, characterized in that it contains mudstones as a clay component, and diopside-containing rock and a cullet as a corrective additive, as alkaline additives - 2N sodium hydroxide solution, as a binder - building gypsum, with a water-clay ratio of 0.42-0.45 and the following ratio of components, wt.%:
Mudstone 69.0-74.8 Diopside-containing rock 10-15 Cullet 9.5-10.5 Building gypsum 4.92-5.1 Aluminum powder 0.58-0.6 Sodium hydroxide, 2N solution (in excess of 100%) 29.6-30.0