LT5834B - Clinker ceramics and method for obtaining thereof - Google Patents

Abstract

The invention could be applied to the production of facade wall ceramics, particularly to brick those facades, which are operated by aggressive conditions (eg., coastal zone). The formation mix of ceramic samples was made from such components: clay, quartz sand and firestone. After formation, drying and burning of samples by appropriate regime (the maximum burning temperature was 1075 1090oC) obtained ceramic body, which forecast frost resistance is more than 1000 cycles (by forecasting methodology 1413.12 BS: 1998), the average compressive strength is 25 MPa, density – 2092 kg/m3, water absorption, which was determined in the normal conditions after 72 hours – 2.1 %, reserve of porous volume - 59,7 %.

Description

The invention relates to clinker ceramic products and can be applied to the production of finishing products such as bricks or tiles. These products have extremely low water absorption and high frost resistance and can be used in aggressive environmental conditions (in the coastal area) where humid cold windy weather prevails.

The ceramic composition of International Application PCT / RU2008 / 0060 is 7581% clay, methyl methacrylate 1-3% and water. The prepared semi-finished products were burnt at a maximum temperature of 800 ° C. The entire combustion process took 20 hours. The authors state that the addition of methyl methacrylate to the molding mass allowed them to reduce the combustion temperature to 120 ° C and to obtain analogous ceramic properties. For example, such specimens have a compressive strength of 30 MPa but water absorption is about 19%.

The author of patent RU2358943, J. A. Shchepochkina, used paper, sawdust, glass waste and a ladder to make ceramic bricks. The specimens were burned at 1000 ° C. The product has a compressive strength of 8-10 MPa. Patent RU2358947 by the same scientist states the composition of pottery: 43-48% clay, nickel slag 36-38%, lead by 8-10% and water 6-11%. Such a mass was burned at 900 ° C and obtained a frost resistant ceramic (220 cycles).

International Application W00021902 discloses how to obtain sintered ceramics. Here, clay, ash and heavy metal oxides (40%) are used to prepare the formation mixture, and the combustion temperature is 1150-1200 ° C. The resulting ceramic has a density of 2,682,85 g / cm ³ . The use of steel slag, 50% by weight of the molding compound and fired at 1200 ° C, gives a product density of up to 3 g / cm ³ and a compressive strength of 6 MPa.

Highly frost resistant ceramics are described in patent SU1675275. Its frost resistance, established by long-standing standards, is 2600 cycles, but water absorption is as high as 13%. Products with these characteristics were obtained using the following composition of the formation mixture: 21-30% clay minerals, 0.005-0.05 mm particle size quartz and 0.051.25 mm particle size quartz sand.

Patent LT3792 discloses a mixture of frost-resistant ceramics (clay 66-86%, sand 10-20%, anthracite with a dispersion less than 0.005 mm 0.5-4% and calcite or dolomite or magnesite with a dispersion less than 0.05 -0.01 mm). For the purposes of this patent, one of the molding masses can be considered as a prototype of our invention because it was obtained from analogous clay 85% and sand 15%. Such a mass was molded in plastic and dried semi-finished products were burnt at 960 ° C. The test specimens have a soak of up to 15% and a resistance to frost of up to 350 cycles.

A method for obtaining clinker ceramics is described in patent RU2148564, having a water absorption of less than 2%. However, 20-30% of lime slag and 3-5% of nepheline-syenite are introduced into the formation mass without clay and quartz sand. The specimens were burned at 920-950 ° C.

RU2137731 was selected as an analog of the invention. Methods and characteristics of obtaining clinker brick and floor tiles are described herein. Clinker bricks were obtained using clay 40-60% and granodiorite (feldspar) 40-60%. Such blanks were burned at 1210 ° C. The water absorption was found to be 1.2-1.4%, but the frost resistance was only 60 cycles. The floor tile forming mass was 52.5-60% clay, 20-30% granodiorite and 17.5-20% kaolin. Specimens of this forming mass were burned at 1150-1180 ° C. The resultant ceramic has a water absorption of 2.8-3.2%, a compressive strength of 3436 MPa and a frost resistance of 40 cycles.

The object of the invention is to provide a clinker (water absorption determined after 72 hours is less than 3%) of frost resistant ceramics.

The proposed clinker ceramic, (the water absorption determined after 72 hours is less than 3%), is new in the composition components of its formulation, in their amounts, dispersion and combustion conditions. The formation mixture used was 76-84% clay, 1218% quartz sand, 4-6% chamotte. In the production of clinker ceramics the combustion is carried out at a temperature of 1075-1090 ° C. The resulting clinkeric ceramics differ in their mineralogical composition. Ceramic minerals found have been quartz, hematite, anorthite, diopside, mullite, and quartz, mullite, crystabolite, and cordierite have been found in additives.

Brief Description of the Drawings In which:

FIG. presented radiograph of clay (X - chlorite, K - kaolinite, I - ilite, Do dolomite, C - calcite, Q - quartz);

FIG. - radiograph of chamotte (M - mulitas, Kr - crystobalite, Co - cordieritas);

FIG. - radiograph of the obtained clinkeric ceramic specimen (Q - quartz, H - hematite, A - anorthite, D - diopside, M - mullite).

The aim of the work was achieved by using the following composition of the forming mixture:

1) Clay (sieved through a 0.63 mm mesh sieve) 76-84%

2) quartz sand (sieved through a 0.63 mm mesh sieve) 12-18%

3) Chamotte (sieved through a 1.25 mm mesh sieve) 4-6%

The chemical composition of the clay is given in Table 1 and the granulometric composition in Table 2.

table. Average chemical composition of clay

Tent nys SiO ₂ AI2O3 + T1O2 Fe2OH CaO MgO K ₂ O Na2O Protective menu Dysnos 51.63 20.09 7.56 5.45 1.46 3.35 1.15 9.1

table. Average granulometric composition of clay

Campsite Content of sand fraction (particles larger than 0.05 mm),% Amount of dust fraction (particle size 0.05 to 0.005 mm),% Amount of molar fraction, (particles smaller than 0.005 mm),% Dysnos 1.76 16.34 81.90

A radiograph of the clay was obtained (Fig. 1).

X-ray analysis of clay (Fig. 1) shows that clay minerals are as follows:

kaolinite K (0.716, 0.450, 0.356) nm, chlorite X (1,420, 0.716, 0.356) nm, quartz Q (0.426, 0.335, 0.246, 0.228, 0.213.0.182, 0.167) nm, dolomite Do (0.289, 0.240,0.219) nm, calcite C (0.385, 0.304, 0.209, 0.191, 0.187) nm, ilite (0.998, 0.500,) and some feldspar F (0.324 nm). The following clays are formed from the initial clay minerals: hematite F (FeaCb), gelenite G (2CaO-Al2O3-SiO2), anorthite A (CaO-AhCb ^ SiCh), diopside D (CaO-MgO-2SiO2), cristobalite Kr (S1O2) ), mulite (3Al2O3'2SiO2), glass phase.

The chemical composition of the quartz sand used is given in Table 3.

table. Average chemical composition of quartz sand

Chemical composition,% SiO ₂ AI2O3 Fe 2 O 3 CaO MgO r ₂ o Injuries 88.16 3.85 0.75 3.20 0.49 1.4 2.15

FIG. a radiograph of the firecracker was provided.

The radiograph of the chamotte shows that the dominant mineral is mulite (0.542,

0.378, 0.339, 0.290, 0.270, 0.256, 0.243, 0.234, 0.230.0.221, 0.213, 0.209, 0.189, 0.185, 0.180, 0.172, 0.170, 0.161, 0.158, 0.153, 0.146, 0.145, 0.141) nm. Mullite and crystabolite (S1O2) are thermodynamically stable minerals, and the incorporation of chamotte from such minerals into the mixture must improve the final properties of the ceramic, especially its frost resistance. Also found in chamotte is cordierite (2MgO 2AI2O3 5S1O2), which is sufficiently inert for thermal expansion.

The obtained ceramic specimens were subjected to radiographic analysis and their phase composition was determined with a DRON-7 diffractometer (Fig. 3 radiograph).

The following minerals were detected in all batches: quartz Q ((SiO ₂ ) 0.154, 0.167, 0.182, 0.198, 0.213, 0.229, 0.246, 0.335, 0.424) nm), hematite H ((Fe ₂ O ₃ ) 0.157, 0.170, 0.184, 0.220 , 0.251, 0.270) nm), anorthiteX ((CaO [Al ₂ Si ₂ O ₈ ] or CaO-Al ₂ O 3-2 SiO ₂ ) 0.251, 0.321.0.324, 0.370, 0.376, 0.406) nm), diopside D ((CaO- MgO-2SiO ₂ ) 0.204, 0.289, 0.298) nm), mullite M ((3Al ₂ O ₃ -2SiO ₂ ) 0.342.0.540 nm) (Fig. 3).

Method of obtaining clinker ceramics:

1) preparation of raw materials (crushing, sieving),

2) mixing of components,

(3) wetting or drying the mixture to a suitable moisture content;

4) formation of semi-finished products,

5) drying and burning in optimum time and temperature mode.

The main characteristics of clinker ceramics and prototype and analogues are given in Table 4. In our case, the resistance to frost was predicted by the structural indicator method (MawjiaHTHc, P. 1997. Mopo3ocmouKocmb u domoeemiocmb U3dejiuū φαοαόηού KepaMUKU. and other finishes with one-sided refrigeration). The operational resistance to frost, as a physical indicator of facade ceramics, can be characterized by its ability to resist defect infiltration due to migration processes.

In the case of the analogue, the frost resistance was determined by the volumetric method and the prototype according to GOST 7025-91, Clause 2. The volumetric method does not meet the operating conditions and results are often unreliable because, depending on the structure of the specimens, the directional refrigeration (as during operation) may cause ceramics to decompose faster than freezing evenly on all sides.

table. Main features and advantages of the invention

Moderate resistance for cold, cycles 1067 350 09 O Average water absorption,% r - l no 15.72 00 no General shrink mas 14.8 1 3- r 'l 6.5 The composition of the forming mixture Kaolin quantity, % 1 1 1 17.5-20 Grana- diorito quantity, % 1 1 40-60 20-30 Chamotte content,% 4-6 1 1 1 Quartz sand content,% 12-18 m 1 1 Clay content,% 76-84 m 00 40-60 52.5-60 Maximum combustion temperature, ° C 1075-1090 960 1210 1180 Offered option Prototype Analogs 1 Analogs2

The resulting clinker ceramics have a relatively large porous space reserve of 59.7% (compared to only 21.4% in the prototype), which is the main indicator of the frost resistance in service. It shows the number of pores and capillaries that are very difficult to penetrate into the water. Offered o

for ceramics, the average density determined is 2092 kg / m, and the compressive strength is also quite high - 25 MPa.

Clinkeric ceramics were obtained using conventional raw materials and compared to the analogue at low burning temperatures. The researchers of the analogue of the invention obtained the clinker ceramic by burning samples at a maximum burning temperature of 1210 ° C, while our clinker ceramic was obtained by burning the samples at 1075-1090 ° C. This significantly reduces energy costs. The clinker pottery offered is also distinguished by the fact that it uses quartz sand and fireclay, which is fire resistant. In addition, all components were finely dispersed. Clay and quartz sand melted at high temperatures and solid phase sintering took place. The driving force for this sintering was the surface tension of the melt, which caused a negative pressure in the closed pore. Under this pressure, the pores of the ceramic material were filled with melt and the grains converged. The more liquid phases are formed and the finer the raw materials, the more intense the diffusion process in the sample. This process causes the grain to regroup, shrink open pores of irregular shape, and form smaller, more regular pores. Substances of this structure are difficult to penetrate into water, and when weather conditions change, water has no ability to change its state, migrate and thus cause internal stresses and material destruction.

Claims (2)

DEFINITION OF INVENTION 1. Clinkeric ceramics, whose molding mixture contains clay and sand, characterized in that the molding mixture consists of the following components and their amounts: clay - 7684%, quartz sand - 12-18%, chamotte - 4-6%. 2. A process for the production of clinker ceramics comprising the preparation of raw materials, the mixing of components, the formation of semi-finished products, drying and combustion, characterized in that the combustion takes place at 1075-1090 ° C. Intensity, imp / s Intensity, imp / s