RU2740177C1 - Method of producing brick glaze - Google Patents

Abstract

FIELD: construction.SUBSTANCE: invention relates to the industry of construction materials and specifically to methods of making brick glazes applied on ceramic bricks used to make structural decorative functions, for finishing of internal walls of vestibules, staircases, passages, interiors of separate architectural elements of buildings and facades. In the method of producing brick glaze, mixture is used as a charge, containing, wt. %: low-melting clay 30–40; blast-furnace slag 17–20; microsilica 13–15; burning out of burnt rock 12–15; flue dust 13–15; water is the rest, and the glaze preparation process is carried out in three stages. At the first stage blast-furnace slag is crushed and burnt rock is screened with addition of water to particle size of 50–60 mcm. At the second step, the obtained suspension is mixed with silica, flue dust and low-melting clay pre-ground to 55–60 mcm. At the third stage, this suspension is sprayed into the upper part of the boiling layer furnace and is heat treated at temperature of 950–1100 °C for 30–40 minutes.EFFECT: technical result is possibility of using glaze for all types of ceramic bricks, as well as high strength and frost resistance.1 cl, 1 dwg, 2 tbl

Description

The invention relates to the building materials industry, in particular to methods for the preparation of brick glazes applied to ceramic bricks used to perform structural decorative functions, to decorate the interior walls of lobbies, staircases, walkways, interiors of individual architectural elements of buildings and facades.

A known method of producing brick glaze, in which the components of the charge are prepared and dispensed to obtain the glaze, then subjected to grinding (RF patent for invention No. 2301217, Brick glaze, IPC C04B 41/86, from 20.06.2007). The resulting suspension is applied to the brick after drying, and then dried again with the applied layer and fired. The method uses a charge for glaze, including light clay, chalk, lead litharge, pyrolusite, metallurgical slag, cullet, with the following ratio of components, parts by weight: low-melting clay 90-100; chalk 10-15; lead litharge 40-50; pyrolusite 6-10; metallurgical slag 10-30; cullet 10-15.

The disadvantages of this method are limited technological capabilities due to the fact that it is applicable only for tripoli bricks, as well as low glaze quality due to the fragile adhesion of the glaze to the tripoli ceramic brick, which is expressed in the formation of a network of cracks in the glaze layer or its rebound from the brick when cooled.

The closest in technical essence and the achieved effect, the proposed is a method of producing brick glaze, in which the components of the batch of brick glaze are crushed until they pass through a 1 mm sieve, thoroughly mixed and fritted at a temperature of 1200 ± 100C and kept for 1 hour (RF Patent for invention No. 2386606, Brick glaze, IPC C04B 41/86, dated 20.04.2010). The molten frit is granulated in running water. Next, the frit is mixed with pigment, white clay and ground to less than 63 microns. The method uses a charge for producing glaze containing low-melting clay, chalk, lead litharge, pyrolusite, metallurgical slag, cullet, tripoli, with the following ratio of components, parts by weight: low-melting clay 60-70; chalk 10-15; lead litharge 40-50; pyrolusite 6-10; metallurgical slag 10-30; cullet 10-15; tripoli 30-35 (in terms of mass%: low-melting clay 30-45; chalk 5-7; lead litharge 20-21; pyrolusite 5-7; metallurgical slag 6-14; cullet 5-6; tripoli 14-15) ... Blast furnace slag is preferably used as the metallurgical slag. The density of the resulting glaze is 1.6-1.7 g / cm ³ .

The disadvantage of the closest analogue, as well as the above mentioned analogue, is the limited technological capabilities associated with its use only for tripoli bricks, as well as low strength and frost resistance.

A technical problem at the present time is the difficulty of obtaining a durable and frost-resistant glaze for a wide range of ceramic bricks.

The technical result of the proposed solution is the possibility of using glaze for all types of ceramic bricks, as well as increasing its strength and frost resistance.

The technical result achieved is achieved by the fact that in the method for producing brick glaze, in which the components of the glaze mixture are prepared and dosed, they are crushed, fritted, heat treated and additionally crushed, according to the proposed solution, a mixture containing the following components, wt%, is taken as a mixture:

low-melting clay 30-40; blast furnace slag 17-20; microsilica 13-15; screening of burnt rock 12-15; carryover dust 13-15; water rest,

and the glaze preparation process is carried out in three stages, while at the first stage blast furnace slag and screening of burnt rock with the addition of water to a particle size of 50-60 microns are crushed, at the second stage the resulting suspension is mixed with silica, entrainment dust and pre-crushed to 55-60 microns with low-melting clay, in the third stage this suspension is sprayed into the upper part of the "fluidized bed" furnace and heat treatment is carried out at a temperature of 950-1100C for 30-40 minutes.

The specified charge has the following chemical composition, wt%:

low-melting refractory clay containing, wt%: SiO ₂ - 52; Al2O ₃ - 16; Fe ₂ O ₃ - 12; CaO - 4.8; MgO 3.4; Na ₂ O - 2.5; K ₂ O - 0.4; MnO 0.3; TiO ₂ - 0.76; P.p. - 8.2;

blast-furnace slag produced by the Satka Metallurgical Plant and containing, wt%: SiO ₂ - 35.3; Al ₂ O ₃ - 13.8; CaO - 29.5; MgO 16.7; FeO - 0.42; MnO - 0.7, used for the manufacture of cement and as a filler for the production of concrete products. However, in the slag yard of such slag, 208.4 thousand tons have been accumulated [Waste of JSC "SMZ" Drobyshev AA Dobrovolsky IP Collection of scientific articles "Condition and development of the raw material base of the construction industry in the Chelyabinsk region." - Chelyabinsk, 2001, p. 20-24];

microsilica is a waste from the production of ferrosilicochromium of JSC ChEMK, containing, wt%: SiO - 83-93; Al ₂ O ₃ - 0.8-1.5; CaO -1.0; MgO - 0.3; Cr ₂ O ₃ - 0.2-0.5 and Fe ₂ O ₃ - 0.5-4.9, partially used in the manufacture of concrete, but a significant amount of it is stored in the dumps of the association;

screening of burnt rock on a sieve with a mesh size of 1 mm from the dumps of the Krasnaya Gornyachka mine, having the following composition, wt%: pp. 1.61-5.66; SiO ₂ 40.17-56.47; Al ₂ O ₃ 8.74-19.74; Fe ₂ O ₃ 4.62-8.39; FeO 0.07-3.85; CaO 4.55-13.88; MgO 1.45-5.4; SO ₃ 0.94-2.37; K ₂ O 0.64-1.78; Na ₂ O 0.32-0.89, which contains active aluminate-dehydrated clay minerals (metakaolinite Al ₂ O ₃ ⋅SiO ₂ ) and active alumina y-Al ₂ O ₃ . Burnt rocks are used partially for the construction of roads [Gamaley E.A., Gorbunov S.P. Ways of utilization of burnt rocks of mine waste heaps in the production of building materials. Sat. Art. scientific. conf, Chelyabinsk: Ed. Center of SUSU. - Chelyabinsk, 2013, p. 150-153].

Carry-over dust obtained by calcining the sludge from the converter production at a special installation of Mechel OJSC, containing, wt%: Fe ₂ O ₃ - 42.3; SiO ₂ 2.1; ZnO 24-26; PbO - 3.6, until it finds use and is stored.

In connection with the use in the claimed method of the proposed mixture for obtaining glaze and conducting in the claimed manner the technological process of preparing the glaze allows the use of this glaze not only for facing bricks from tripoli, but for other types of ceramic bricks.

When obtaining a glaze in the composition used to obtain it, the following reactions occur (1-4) with the formation of calcium metakaolinite, calcium aluminate and, on its basis, alumina cement

CaO + H₂O = Ca (OH)₂ (one)

Al₂O₃+ 3Ca (OH)₂= 3CaO * Al₂O₃+ H₂O (2)

Al ₂ O ₃ * 2SiO ₂ + Ca (OH) ₂ + nH ₂ O = CaO * Al ₂ O ₃ * 2SiO ₂ * nH ₂ O (3)

3CaO * Al ₂ O ₃ + 6H ₂ O = 3CaO * Al ₂ O ₃ * 6H ₂ O (4)

The formation of active calcium metakaolinite and alumina cement in the glaze increases its strength and frost resistance. In connection with the use in the claimed method of the proposed charge for obtaining glaze by carrying out the developed 'technological process for preparing glaze with the formation of metakaolinite and alumina cement in it, it allows the use of such glaze not only for facing bricks from tripoli, but also for other types of ceramic bricks.

It is most rational to apply such glaze to a hot brick after it leaves the oven. The glaze is firmly sintered with the hot surface of the brick, and the lead of dust-entrainment in a molten form penetrates into the pores and cracks of the brick, further increasing the strength of the bond without micropores and cracks with high adhesion to the brick. A lower temperature of the glaze heat treatment is achieved due to the content of low-melting clay in it, which has a high flow coefficient, which simplifies the application of the glaze to the brick, making the protective and decorative coating of red color with iron oxide dust-entrainment and burnt rock.

The increase in the content of the used charge of low-melting clay more than 40 wt. % will lead to a decrease in the strength of the glaze, and a decrease in its content is less than 30 wt. % reduces the rate of reactions.

An increase in the content of blast-furnace slag over 20 wt.% Will lead to an excess of calcium, and a decrease in this content is less than 17 wt.%. % o will reduce the formation of metakaolinite and alumina cement, the strength and frost resistance of the glaze.

An increase in the content of microsilica more than 15 wt.% Will require an increase in the consumption of low-melting clay by more than 40 wt.%, And a decrease in this content to less than 13 wt.% Will lead to a decrease in the quality of the glaze.

An increase in the content of rock screenings of more than 15 wt% will require an increase in the content of blast furnace slag of more than 20 wt%, and a decrease in this content to less than 12 wt%) will lead to a decrease in the formation of metakaolinite and cement.

An increase in the dust-entrainment content of more than 15 wt.% Will lead to an excess of cement in the glaze, and a decrease in this content to less than 13 wt.% Will lead to a decrease in lead in the glaze and, accordingly, its adhesion strength with bricks.

Reducing the size of particles when grinding blast-furnace slag with screening of burnt rock less than 50 microns is impractical, because the grinding time is significantly increased with a slight increase in the quality of the glaze, grinding to particles greater than 60 microns further reduces the rate of formation and quality of the frit. Pre-grinding low-melting clay less than 55 microns will lead to a significant increase in energy and process time, and an increase in this size above 60 microns will reduce the strength of the glaze.

Thermal treatment of the suspension at the third stage of glaze production below 950 ° C reduces the rate of formation of alumina cement, and at temperatures above 1100 ° C the rate of cement formation practically does not increase and energy consumption increases.

An increase in the heat treatment time in the third stage for more than 40 minutes will lead to energy consumption without increasing the quality of the glaze, and a decrease in this time less than 30 minutes does not provide a complete melt of the mixture.

The proposed method for producing brick glaze is illustrated by the flow diagram in Fig. one.

The method for producing brick glaze is carried out as follows.

The peculiarity of the technological scheme for the manufacture of brick glaze from the specified raw materials is carried out in three stages in the following sequence.

At the first stage in a bead mill 7, the calculated amount of blast-furnace slag is ground with screening of burnt rock, supplied, respectively, from bunkers 2 and 3 with the addition of water for 20 minutes to a particle size of 50-60 μm. In this case, the temperature of the mixture rises to 150-160 ° C, and reactions proceed with the formation of calcium aluminate and calcium metakaolinite (1, 2, 3).

After the end of the reactions, the suspension is transferred through the intermediate tank 8 by a slurry pump 9 to the second stage into a two-roll mixer 11, which is also fed with the calculated amounts of microsilica from the bunker 6, dust-carryover from the converter production from the bunker 5, pre-crushed to 55-60 μm in the dismembrator 10 low-melting refractory clay supplied from the hopper 1.

Next, the mixture, after mixing in a two-roll mixer 11, is transferred to the third stage by spraying into the upper part of the fluidized bed furnace 12, in which the mixture is subjected to heat treatment at a temperature of 950-1100C for 30-40 minutes with the formation of a glaze, which is collected in a container 13 of hot glaze ... In this case, reaction (4) simultaneously proceeds in the furnace with the formation of alumina cement. The dust removed from the furnace 12 is captured by the cyclone 14 and returned to the hot glaze tank 13, after which bricks 16 are covered with hot glaze on the stand 15, which are transferred to the storage 17.

According to the proposed solution, a brick glaze was made, which was applied to a ceramic brick. Four samples were tested in accordance with GOST 27180-2001 in the brick production laboratory of OJSC "Korkinsky Ceramic Plant". Samples 1 and 2 were made according to the claimed solution, samples 3 and 4 were made in accordance with the closest analogue. The test results are summarized in table. 12.

table 2

Glaze processing conditions and product quality

No.
p.p. Heat treatment conditions Glaze indicators Sample
# 1 Sample
# 2 Sample
No. 3 Sample
# 4 Temperature, ⁰ С 950 1100 1190 1210 Time, min. thirty thirty 60 60 one Water absorption
layer,% 1.27 1.09 3.12 2.86 2 Strength,
MPa 40 45 25 27 3 Frost resistance,
cycles 62 71 fifty fifty 4 Cracks,
cm * cm ² 0.008 0.006 0.054 0.035

From the data in the table it can be seen that the obtained glaze samples are characterized, in comparison with the closest analogue, not only by high strength and frost resistance, but also practically have no cracks and have a high quality protective and decorative red coating. The use of the proposed glaze will also improve the environmental situation in connection with the use of production waste.

The proposed method for producing brick glaze will find application in the construction industry for finishing work.

Claims (3)

A method for producing brick glaze, in which the components of the glaze mixture are prepared and dispensed, crushed, fritted, heat-treated and additionally crushed, characterized in that a mixture containing the following components, wt% is taken as the mixture: low-melting clay 30-40 blast furnace slag 17-20 microsilica 13-15 screening of burnt rock 12-15 carryover dust 13-15 water rest, and the glaze preparation process is carried out in three stages, while at the first stage blast furnace slag and screening of burnt rock with the addition of water to a particle size of 50-60 microns are crushed, at the second stage the resulting suspension is mixed with silica, entrainment dust and pre-crushed to 55-60 microns fusible clay, in the third stage this suspension is sprayed into the upper part of the "fluidized bed" furnace and heat treatment is carried out at a temperature of 950-1100 ° C for 30-40 minutes.

Images