CN113173794B

CN113173794B - Corundum composite brick and preparation method thereof

Info

Publication number: CN113173794B
Application number: CN202110602388.2A
Authority: CN
Inventors: 蔡斌利; 占华生; 卫迎锋; 范明明; 高长贺
Original assignee: Beijing Jinyu Tongda Refractory Technology Co ltd
Current assignee: Beijing Jinyu Tongda Refractory Technology Co ltd
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2022-11-15
Anticipated expiration: 2041-05-31
Also published as: CN113173794A

Abstract

The invention provides a corundum composite brick and a preparation method thereof. The corundum composite brick comprises a corundum heavy layer and a heat insulation layer combined with the corundum heavy layer; the corundum heavy layer comprises the following raw materials: 35 to 75 weight percent of corundum, 10 to 30 weight percent of andalusite, 5 to 15 weight percent of alumina powder, 0 to 10 weight percent of chromium oxide powder, 0 to 10 weight percent of zirconia powder and 3 to 8 weight percent of bonding clay; the heat insulation layer comprises the following raw materials: 15-65 wt% of alumina hollow spheres, 15-65 wt% of mullite, 5-15 wt% of alumina powder and 3-8 wt% of combined clay. The corundum composite brick not only has excellent refractoriness and heat insulation effect, reduces heat loss, but also is convenient to construct, has stable structure, and can improve the use stability and the operation efficiency of equipment in a rotary kiln.

Description

Corundum composite brick and preparation method thereof

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to a corundum composite brick and a preparation method thereof.

Background

The rotary kiln is the main equipment in a hazardous waste incineration system, and the service cycle and the heat dissipation loss are greatly influenced by the performance of a surface refractory material.

The existing rotary kiln refractory brick generally comprises a single-layer brick structure and a double-layer brick structure, wherein the surface temperature of a rotary cylinder body with the single-layer brick structure is too high, so that the problems of deformation of the cylinder body, ignition of a transmission gear box and the like are easily caused. The heavy-weight brick and the light-weight heat-insulating brick are compositely built and applied to the rotary kiln, so that the temperature of the surface of the barrel can be reduced, the heat radiation loss of the rotary kiln barrel is effectively reduced, the deformation of the rotary kiln barrel is reduced, and the integral service life of the barrel and equipment is prolonged. But the heavy brick and the heat-insulating brick which are coaxially built have poor stability, a gap can be formed between the heavy brick and the heat-insulating brick in the later period of service, the heavy brick and the heat-insulating brick are mutually extruded, crushed, slid and the like, the brick falling phenomenon is easy to occur, and the construction requirement is high.

In order to solve the problems of crushing, slipping and the like in the composite masonry of heavy bricks and light heat-insulating bricks, the composite bricks are prepared by pressing, forming and sintering heavy layer pug and heat-insulating layer pug, but cracks are easy to appear at the joint of the two layers due to different materials, and the use risk is high.

Disclosure of Invention

The invention provides a corundum composite brick and a preparation method thereof, wherein the corundum heavy layer and a heat insulation layer have high bonding strength, and cracks can not occur.

Specifically, the invention provides the following technical scheme:

a corundum composite brick comprises a corundum heavy layer and a heat insulation layer combined with the corundum heavy layer;

the corundum heavy layer comprises the following raw materials: 35 to 75 weight percent of corundum, 10 to 30 weight percent of andalusite, 5 to 15 weight percent of alumina powder, 0 to 10 weight percent of chromium oxide powder, 0 to 10 weight percent of zirconia powder and 3 to 8 weight percent of bonding clay;

the heat insulation layer comprises the following raw materials: 15-65 wt% of alumina hollow spheres, 15-65 wt% of mullite, 5-15 wt% of alumina powder and 3-8 wt% of combined clay.

The inventor finds that the thermal expansion coefficient of the thermal insulation layer material can be matched with the thermal expansion coefficient of the working layer material by controlling the combination of the heavy layer and the thermal insulation layer under the raw materials with specific composition and content, the bonding strength of the interface of the two materials is improved, cracks cannot appear at the joint, the heavy layer can still keep excellent refractoriness, and the thermal insulation layer can still keep high porosity and has excellent thermal insulation effect.

Preferably, in the corundum composite brick, the corundum heavy layer comprises the following raw materials: 57-65 wt% of corundum, 18-25 wt% of andalusite, 6-7 wt% of alumina powder, 3-5 wt% of chromium oxide powder, 1-3 wt% of zirconia powder and 4-6 wt% of bonding clay.

Preferably, in the corundum composite brick, the heat insulation layer comprises the following raw materials: 42-52 wt% of alumina hollow spheres, 17-22 wt% of mullite, 8-10 wt% of alumina powder and 6-8 wt% of combined clay. Further preferably, the 42-52 wt% hollow alumina spheres are specifically: 15 to 0.5mm of alumina hollow ball, 12 to 17wt of 0 to 1mm of alumina hollow ball and 15 to 20wt of 1 to 3mm of alumina hollow ball.

Preferably, in the corundum composite brick, the corundum heavy layer comprises the following raw materials: the grain size of corundum is less than or equal to 5mm, the grain size of andalusite is less than or equal to 3mm, the grain size of alumina powder is less than 10 mu m, the grain size of chromium oxide powder is less than 10 mu m, the grain size of zirconia powder is less than 10 mu m, and the grain size of combined clay is less than 0.074mm. Under the granularity, the good construction performance of the product can be ensured.

Preferably, in the corundum composite brick, the heat insulation layer comprises the following raw materials: the grain diameter of the alumina hollow ball is less than or equal to 3mm, the grain diameter of the mullite is less than or equal to 3mm, the grain diameter of the alumina powder is less than 10 mu m, and the grain diameter of the combined clay is less than 0.074mm. Under the granularity, the good construction performance of the product can be ensured.

Preferably, in the corundum composite brick, the thickness of the corundum heavy layer is 150-250 mm, and the thickness of the thermal insulation layer is 50-100 mm.

The invention also provides a preparation method of the corundum composite brick, which comprises the following steps:

mixing powder materials including alumina powder, chromium oxide powder, zirconia powder and combined clay according to the raw material composition of the corundum heavy layer to obtain first mixed powder material; mixing granules comprising corundum and andalusite to obtain a first mixed granule; adding a first binding agent into the mixed granular material, wet-mixing for 5-7 min, further adding the first mixed powder, wet-grinding for 15-30 min, and ageing mixture for 8-10 h to obtain corundum heavy layer pug;

mixing powder comprising alumina powder and clay according to the raw material composition of the heat insulation layer to obtain second mixed powder; mixing the granules comprising the alumina hollow spheres and the mullite to obtain a second mixed granule; adding a second binding agent into the mixed granular material, wet-mixing for 5-7 min, further adding a second mixed powder, wet-grinding for 15-30 min, and ageing for 8-10 h to obtain a thermal insulation layer mud material;

providing a mould with a partition plate, respectively adding the corundum heavy layer pug and the thermal insulation layer pug to two sides of the partition plate, removing the partition plate, performing machine-pressing molding, drying at 100-120 ℃ for 10-12 h, and firing at 1550-1650 ℃ for 8-12 h to obtain the corundum composite brick.

Preferably, in the above preparation method, the first binding agent is selected from a solution of aluminum dihydrogen phosphate having a specific gravity of 1.20 to 1.35g/mL, and the amount of the first binding agent is 3 to 5wt% based on the total mass of the raw materials of the corundum heavy layer.

Preferably, in the above preparation method, the second binder is selected from an aluminum dihydrogen phosphate solution with a specific gravity of 1.20-1.35 g/mL, and the amount of the second binder is 3-5 wt% of the total mass of the raw materials of the heat insulation layer.

Preferably, in the preparation method, two opposite sides of the partition plate are both in a sawtooth shape, so that the contact area between the corundum heavy layer and the heat insulation layer is increased, and the bonding strength is improved.

The invention has the following beneficial effects:

the corundum composite brick provided by the invention has excellent refractoriness and heat insulation effect, reduces heat loss, is convenient to construct, has a stable structure, and can improve the use stability and the operation efficiency of equipment when being used in a rotary kiln.

Drawings

FIG. 1 is a schematic structural view of the corundum composite brick obtained in example 1, wherein 1 is a corundum heavy layer, and 2 is a thermal insulation layer.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. The examples do not specify particular techniques or conditions, and are to be construed in accordance with the description of the art in the literature or with the specification of the product.

In the following examples, the equipment and the like used are not shown to manufacturers, and are all conventional products available from regular vendors. The process is conventional unless otherwise specified, and the starting materials are commercially available from the open literature.

Example 1

Embodiment 1 provides a corundum composite brick, as shown in fig. 1, which comprises a corundum heavy layer 1 and a heat insulation layer 2 combined with the corundum heavy layer, wherein the thickness of the corundum heavy layer is 250mm, and the thickness of the heat insulation layer is 50mm.

The corundum heavy layer 1 comprises the following raw materials: 65wt% corundum (< 5 mm), 18wt% andalusite (< 3 mm), 7wt% alumina powder (< 10 μm), 3wt% chromium oxide powder (< 10 μm), 2wt% zirconia powder (< 10 μm), 5wt% clay binder (< 0.074 mm).

The heat insulation layer 2 comprises the following raw materials: 15wt% of alumina hollow spheres (1-3 mm), 17wt% of alumina hollow spheres (0.5-1 mm), 15wt% of alumina hollow spheres (0-0.5 mm), 22wt% of 60 mullite (1-3 mm), 15wt% of andalusite powder (less than 0.088 mm), 10wt% of calcined alumina powder (less than 10 mu m) and 6wt% of bound clay (less than 0.074 mm).

The corundum composite brick is prepared by the following steps:

1) Mixing powder materials including alumina powder, chromium oxide powder, zirconia powder and combined clay according to the raw material composition of the corundum heavy layer 1 to obtain first mixed powder material; mixing granules comprising corundum and andalusite to obtain a first mixed granule; adding an aluminum dihydrogen phosphate solution into the mixed granules, wet-mixing for 6min, further adding the first mixed powder, wet-grinding for 20min, and ageing for 8h to obtain corundum heavy-weight layer pug; the specific gravity of the aluminum dihydrogen phosphate solution is 1.32g/mL, and the adding amount of the aluminum dihydrogen phosphate solution is 3% of the total mass of the raw materials of the corundum heavy layer;

2) Mixing powder materials comprising alumina powder, bonding clay and andalusite powder according to the raw material composition of the heat insulation layer 2 to obtain second mixed powder material; mixing the granules comprising the alumina hollow spheres and the mullite to obtain a second mixed granule; adding an aluminum dihydrogen phosphate solution into the mixed granules, wet-mixing for 6min, further adding the second mixed powder, wet-grinding for 20min, and ageing for 8h to obtain a thermal insulation layer mud material; the specific gravity of the aluminum dihydrogen phosphate solution is 1.32g/mL, and the adding amount of the aluminum dihydrogen phosphate solution is 3% of the total mass of the raw materials of the heat insulation layer;

3) Providing a mould with a partition plate, wherein two opposite sides of the partition plate are both in a sawtooth shape, respectively adding corundum heavy layer pug and thermal insulation layer pug to two sides of the partition plate, removing the partition plate, performing machine pressing, drying at 120 ℃ for 10h, and firing at 1620 ℃ for 10h to obtain the corundum composite brick, wherein the performance indexes of the corundum composite brick are shown in table 1.

Example 2

Embodiment 2 provides a corundum composite brick, including corundum heavy layer and the insulating layer that combines together with it, the thickness on corundum heavy layer is 230mm, the thickness of insulating layer is 70mm.

The corundum heavy layer comprises the following raw materials: 57wt% corundum (< 5 mm), 25wt% andalusite (< 3 mm), 6wt% alumina powder (< 10 μm), 5wt% chromium oxide powder (< 10 μm), 2wt% zirconia powder (< 10 μm), 5wt% clay binder (< 0.074 mm).

The heat insulation layer comprises the following raw materials: 20wt% of alumina hollow spheres (1-3 mm), 12wt% of alumina hollow spheres (0.5-1 mm), 15wt% of alumina hollow spheres (0-0.5 mm), 17wt% of 60 mullite (1-3 mm), 22wt% of andalusite powder (< 0.088 mm), 8wt% of calcined alumina powder (< 10 mu m) and 8wt% of bound clay (< 0.074 mm).

The corundum composite brick is prepared by the following steps:

1) Mixing powder materials including alumina powder, chromium oxide powder, zirconia powder and combined clay according to the raw material composition of the corundum heavy layer to obtain first mixed powder material; mixing granules comprising corundum and andalusite to obtain a first mixed granule; adding an aluminum dihydrogen phosphate solution into the mixed granules, wet-mixing for 6min, further adding the first mixed powder, wet-grinding for 20min, and ageing for 8h to obtain corundum heavy-layer pug; the specific gravity of the used aluminum dihydrogen phosphate solution is 1.32g/mL, and the adding amount of the aluminum dihydrogen phosphate solution is 3% of the total mass of the raw materials of the corundum heavy layer;

2) Mixing powder materials comprising alumina powder, bonding clay and andalusite powder according to the raw material composition of the heat insulation layer to obtain second mixed powder material; mixing the granules comprising the alumina hollow spheres and the mullite to obtain a second mixed granule; adding an aluminum dihydrogen phosphate solution into the mixed granules, wet-mixing for 6min, further adding the second mixed powder, wet-grinding for 20min, and ageing for 8h to obtain a thermal insulation layer mud material; the specific gravity of the aluminum dihydrogen phosphate solution is 1.32g/mL, and the adding amount of the aluminum dihydrogen phosphate solution is 3% of the total mass of the raw materials of the heat insulation layer;

3) Providing a mould with a clapboard, wherein two opposite sides of the clapboard are both in a sawtooth shape, respectively adding corundum heavy layer pug and thermal insulation layer pug to two sides of the clapboard, removing the clapboard, performing machine pressing molding, drying at 120 ℃ for 10h, and firing at 1600 ℃ for 10h to obtain the corundum composite brick, and the performance indexes of the corundum composite brick are shown in table 1.

Example 3

Compared with the embodiment 1, the difference is only that the raw material composition of the heat insulation layer comprises: the heat insulation layer 2 comprises the following raw materials: 35wt% of alumina hollow spheres (1-0 mm), 27wt% of 60 mullite (1-3 mm), 25wt% of andalusite powder (< 0.088 mm), 8wt% of calcined alumina powder (< 10 mu m) and 5wt% of bound clay (< 0.074 mm). The performance index is shown in Table 1.

TABLE 1 Performance index

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, it is intended that all such modifications and alterations be included within the scope of this invention as defined in the appended claims.

Claims

1. A corundum composite brick is characterized by comprising a corundum heavy layer and a heat insulation layer combined with the corundum heavy layer; the thickness of the corundum heavy layer is 250mm, and the thickness of the thermal insulation layer is 50mm;

the corundum heavy layer comprises the following raw materials: 65wt% of corundum with the grain diameter of less than or equal to 5mm, 18wt% of andalusite with the grain diameter of less than or equal to 3mm, 7wt% of alumina powder with the grain diameter of less than 10 mu m, 3wt% of chromium oxide powder with the grain diameter of less than 10 mu m, 2wt% of zirconia powder with the grain diameter of less than 10 mu m and 5wt% of bonding clay with the grain diameter of less than 0.074 mm;

the heat insulation layer comprises the following raw materials: 15wt% of alumina hollow spheres with the particle size of 1-3mm, 17wt% of alumina hollow spheres with the particle size of 0.5-1mm, 15wt% of alumina hollow spheres with the particle size of 0-0.5 mm, 22wt% of 60 mullite with the particle size of 1-3mm, 15wt% of andalusite powder with the particle size of less than 0.088mm, 10wt% of calcined alumina powder with the particle size of less than 10 mu m and 6wt% of combined clay with the particle size of less than 0.074 mm;

the corundum composite brick is prepared by the following steps:

1) Mixing powder materials including alumina powder, chromium oxide powder, zirconia powder and combined clay according to the raw material composition of the corundum heavy layer to obtain first mixed powder material; mixing granules comprising corundum and andalusite to obtain a first mixed granule; adding an aluminum dihydrogen phosphate solution into the mixed granules, wet-mixing for 6min, further adding the first mixed powder, wet-grinding for 20min, and ageing for 8h to obtain corundum heavy-layer pug; the specific gravity of the aluminum dihydrogen phosphate solution is 1.32g/mL, and the adding amount of the aluminum dihydrogen phosphate solution is 3% of the total mass of the raw materials of the corundum heavy layer;

2) Mixing powder materials including alumina powder, bonding clay and andalusite powder according to the raw material composition of the heat-insulating layer to obtain second mixed powder material; mixing the granules comprising the alumina hollow spheres and the mullite to obtain a second mixed granule; adding an aluminum dihydrogen phosphate solution into the mixed granules, wet-mixing for 6min, further adding the second mixed powder, wet-grinding for 20min, and ageing for 8h to obtain a thermal insulation layer mud material; the specific gravity of the aluminum dihydrogen phosphate solution is 1.32g/mL, and the adding amount of the aluminum dihydrogen phosphate solution is 3% of the total mass of the raw materials of the heat insulation layer;

3) Providing a mould with a partition plate, wherein two opposite sides of the partition plate are both in a sawtooth shape, respectively adding corundum heavy layer pug and heat insulation layer pug to two sides of the partition plate, removing the partition plate, performing machine pressing molding, drying at 120 ℃ for 10 hours, and firing at 1620 ℃ for 10 hours to obtain the corundum composite brick.