CN101863674A - A corundum hollow sphere structure heat insulation integrated composite brick and its preparation method - Google Patents

Abstract

The invention discloses a corundum hollow sphere structure heat insulation integrated composite brick and a preparation method thereof. It includes a heavy support layer of dense high-alumina bauxite, and a lightweight heat insulation layer with corundum hollow spheres as lightweight aggregates, which are composited by vibration pressing or machine pressing. The heavy support layer and light weight The length-to-dimension ratio of the thermal insulation layer is 1-5:2-1. The invention overcomes the high thermal conductivity and short service life of corundum bricks and high-alumina bricks used in high-temperature kilns; and overcomes the problems of low load softening temperature of existing alumina hollow ball bricks and corundum hollow ball bricks, and easy kiln body protrusions and the like when used for a long time. The invention provides a structure and heat insulation integrated composite brick with high refractoriness, good structural strength and good thermal insulation performance.

Description

A corundum hollow sphere structure heat insulation integrated composite brick and its preparation method

technical field

The invention relates to a refractory composite brick and a preparation method thereof, in particular to a corundum hollow ball structure heat-insulating integrated composite brick and a preparation method thereof.

Background technique

High temperature resistant heat insulation material is a key part of thermal equipment such as various kilns. High temperature resistant heat insulation material is directly in contact with the flame, which requires both high temperature resistance and heat insulation and energy saving, and the performance requirements of the material are particularly high. Develop materials with light weight, high strength, good thermal shock stability, and high operating temperature that can meet the needs of high-temperature kilns with light structures, and change the traditional high-temperature kilns that use heavy materials that have large heat capacity, low heating rate, and high energy consumption. Short service life, large amount of construction and maintenance, etc., serve for building a resource-saving and environment-friendly society.

Alumina hollow spheres have been widely used in the field of refractory heat preservation and heat insulation. The hollow spheres take advantage of the large thermal resistance of the closed cavity, which has good heat insulation effect, high strength, high temperature resistance and peeling resistance. Lightweight alumina hollow ball products overcome the characteristics of low strength and poor high-temperature creep resistance of foamed alumina products. Not only can they be directly exposed to flames, but they can also be used as heat insulation layers, but their softening temperature under load needs to be further improved, especially After the furnace life is increased, due to the entry of low-melting volatile components in the flue gas and the long-term creep effect, the furnace lining is easily deformed and the furnace roof collapses. In order to further extend the life of the kiln and meet the requirements of energy saving and consumption reduction, the Inorganic Non-metallic Materials Research Institute of the Department of Materials, Zhejiang University, combined with its advantages in high-temperature material preparation and high-temperature energy-saving technology, developed corundum hollow balls using the proprietary technology of the research institute. Structural heat insulation integrated composite brick, the dense high alumina support layer is used for load bearing, while improving the kiln compactness and reducing high temperature creep, the light heat insulation layer is mainly used for heat insulation and improving thermal shock resistance, so as to further improve the furnace Age, to achieve the purpose of saving energy and reducing consumption. When building a kiln, pay attention that the light layer is in contact with the flame, otherwise it will not improve the service life.

Contents of the invention

In order to overcome the shortcomings of the existing high-temperature kiln heavy corundum brick structure and lightweight hollow ball brick structure, the purpose of the present invention is to provide a corundum hollow ball structure heat insulation integrated composite brick and its preparation method, using heavy and light A combination of ways to reduce heat capacity, overcome creep, and improve life.

The technical solution adopted by the present invention to solve its technical problems is:

1. A corundum hollow ball structure heat insulation integrated composite brick:

It consists of a heavy support layer of dense high-alumina bauxite, and a lightweight heat insulation layer with corundum hollow spheres as lightweight aggregates. It is 1～5:2～1.

2. A preparation method of corundum hollow sphere structure heat insulation integrated composite brick:

A. The raw material ratio of the heavy support layer and the light insulation layer is as follows:

1. In the dense high-alumina bauxite heavy support layer, the mass percentage of each component is:

1 ~ 3mm high bauxite 35 ~ 45%; less than mm high bauxite 20 ~ 35%; no more than 325 mesh high bauxite 20 ~ 35%; clay powder 5 ~ 10%; additional binder 3 ~ 5% ;

2. The lightweight insulation layer is a lightweight insulation layer with corundum hollow spheres as lightweight aggregates, and its technical indicators and content ratios are as follows:

In the corundum hollow sphere high-strength and light-weight insulation layer, the mass percentage of Al ₂ O ₃ is >92%, the particle size is 0.2-5mm, and the natural bulk density is 0.6-0.9g/cm ³ ; the mass percentage of each component It is: 34-60% of corundum hollow spheres, 40-66% of α-Al ₂ O ₃ micropowder, and 30-35% of the mass percentage of α-Al ₂ O ₃ micropowder as the added binder;

B. Preparation method of corundum hollow sphere structural heat insulation integrated composite brick:

(1) Preparation of heavy support layer: first mix the powder not larger than 325 mesh in proportion and mix it evenly in the ball mill, then add the mixed powder after the rest of the aggregate particles and the binder are mixed evenly, and stir for 10~ Ready after 30 minutes;

(2) Preparation of lightweight heat insulation layer: use corundum hollow spheres as lightweight aggregates, mix the lightweight aggregates with the binder in proportion, then add powder in proportion and stir for 10-30 minutes for later use;

(3) Molding: After the batching is completed, the material cavity of the forming mold is divided into two parts by a partition. Plates are formed by vibrating pressure or machine pressing;

(4) Firing: The shaped green body is taken out and dried at 80-150°C, then loaded into a kiln and kept at 1500-1650°C for 3-8 hours for firing.

In the lightweight heat insulation layer, the binder is phosphoric acid solution or aluminum dihydrogen phosphate solution.

In the dense magnesium high alumina heavy support layer, the binding agent is an organic binding agent or a phosphoric acid solution or an aluminum dihydrogen phosphate solution.

Corundum hollow spheres are electromelted blown hollow spheres with an alumina content of 92-98%. The crystal form is mainly α-Al ₂ O ₃ microcrystals. The spheres can still maintain good performance in kilns with temperatures as high as 1700°C. It is a new type of high temperature insulation material with excellent physical and chemical stability. Using it as an aggregate, introducing α-Al ₂ O ₃ fine powder, mullite fine powder, bauxite fine powder, clay and binders, etc., can prepare corundum hollow ball bricks or castables of various matrices, with a density of 1.2 to 1.8 g/cm ³ . If polystyrene microspheres or sawdust or foaming agent are introduced, the density can be lower than 0.6g/cm ³ . High and low shrinkage.

The beneficial effects that the present invention has are:

The invention can change the existing defects of the existing heavy brick structure or the hollow spherical brick lining structure kiln, prolong the service life of the kiln and reduce the cost.

Description of drawings

The accompanying drawing is a structure diagram of corundum hollow ball structure heat insulation integrated composite brick.

In the figure: 1. Heavy support layer, 2. Light heat insulation layer.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in the accompanying drawings, the present invention includes a heavy support layer of dense high-alumina bauxite, and a lightweight heat-insulating layer with corundum hollow spheres as lightweight aggregates, which are composited from the two, and the heavy support layer and light weight The length-to-dimension ratio of the thermal insulation layer is 1-5:2-1. The dense high-alumina bauxite heavy support layer is resistant to high temperature creep; the light insulation layer faces the flame for heat insulation and has high thermal shock resistance.

Example 1:

This embodiment is made of dense high-alumina bauxite refractory materials and corundum hollow spheres. The raw materials and mass percentages used for the heavy support layer are: 1-3mm high-alumina 35%, less than mm high-alumina 30%, No more than 325 mesh high bauxite 30%, clay 5%, plus 3% yellow dextrin solution; the raw materials and mass percentages used for the light heat insulation layer are: corundum hollow ball 65%, α-Al ₂ 35% of the O ₃ micropowder, and 35% of the mass percentage of the α-Al ₂ O ₃ micropowder as the added phosphoric acid binder.

The preparation process comprises the following steps:

(1) Batching: The batching process of the heavy support layer is to mix the powder not larger than 325 mesh in proportion and mix it evenly in the ball mill, and then add the mixed powder after the rest of the aggregate particles and the binder are mixed evenly , stirred for 10-30 minutes and then set aside; the batching process of the light heat insulation layer is to mix corundum hollow balls and phosphoric acid binder in proportion, and then add α-Al ₂ O ₃ in proportion and stir for 10-30 minutes and set aside.

(2) Molding: After the batching is completed, the size ratio between the heavy support layer and the light heat insulation layer is determined according to the use position, wear rate and service life of the material, and the material cavity of the molding mold is separated into parts according to the ratio. The two parts, after feeding materials, pull out the partition, and adopt vibration and pressure molding.

(3) Firing: The shaped green body is taken out and dried at 80-150°C, then put into a kiln and kept at 1650°C for 3 hours for firing.

Example 2:

This embodiment is made of dense high-alumina refractory materials and corundum hollow spheres. The raw materials and mass percentages used for the heavy support layer are: 1-3mm high-alumina 45%, less than mm high-alumina 25% soil, 15% bauxite not greater than 325, 15% clay, plus 5% lignosulfonate; the raw materials and mass percentages used for the light heat insulation layer are: corundum hollow ball 38%, α- 62% of the Al ₂ O ₃ micropowder, and 31% of the mass percentage of the α-Al ₂ O ₃ micropowder added with an aluminum dihydrogen phosphate binder.

The preparation process comprises the following steps:

(1) Batching: The batching process of the heavy support layer is to mix the powder not larger than 325 mesh in proportion and mix it evenly in the ball mill, and then add the mixed powder after the rest of the aggregate particles and the binder are mixed evenly , stirred for 10-30 minutes and then set aside; the batching process of the high-strength light-weight insulation layer is to mix corundum hollow balls with aluminum dihydrogen phosphate binder in proportion, and then add α-Al ₂ O ₃ in proportion and stir for 10-30 minutes spare.

(2) Molding: After the batching is completed, the size ratio between the heavy support layer and the light heat insulation layer is determined according to the use position, wear rate and service life of the material, and the material cavity of the molding mold is separated into parts according to the ratio. The two parts are drawn out after adding materials, and are formed by machine pressing.

(3) Firing: The shaped green body is taken out and dried at 80-150°C, then loaded into a kiln and kept at 1500°C for 3-8 hours for firing.

Example 3:

This embodiment is made of dense high-alumina refractory materials and corundum hollow spheres. The raw materials and mass percentages used for the heavy support layer are: 1-3mm high-alumina 45%, less than mm high-alumina 20% soil, 25% bauxite not larger than 325 mesh, 10% clay, plus 3% polyvinyl alcohol solution; the raw materials and mass percentages used for the light heat insulation layer are: corundum hollow ball 60%, α- 40% of Al ₂ O ₃ micropowder, and 35% of the mass percent of α-Al ₂ O ₃ micropowder as the binder of aluminum dihydrogen phosphate solution.

The preparation process comprises the following steps:

(1) Batching: The batching process of the heavy support layer is to mix the powder not larger than 325 mesh in proportion and mix it evenly in the ball mill, and then add the mixed powder after the rest of the aggregate particles and the binder are mixed evenly , stirred for 10-30 minutes and then set aside; the batching process of the high-strength light-weight heat insulation layer is to mix the corundum hollow spheres with the aluminum dihydrogen phosphate solution binder in proportion, and then add α-Al ₂ O ₃ in proportion and stir for 10-30 minutes to spare.

(2) Molding: After the batching is completed, the size ratio between the heavy support layer and the light heat insulation layer is determined according to the use position, wear rate and service life of the material, and the material cavity of the molding mold is separated into parts according to the ratio. The two parts are drawn out after feeding, and formed by vibrating pressure or machine pressing.

(3) Firing: The shaped body is taken out and dried at 80-150°C, then put into a kiln and kept at 1650°C for 3-8 hours for firing.

Example 4:

In this embodiment, dense high-alumina bauxite refractory material is used. The aggregate of the light insulation layer is made of corundum hollow spheres. The raw materials and mass percentages of the heavy support layer are: 1-3mm high-alumina bauxite 40%, less than mm high bauxite 30%, no more than 325 mesh high bauxite 20%, clay 10%, plus 4% yellow dextrin solution; the raw materials and mass percentages used in the light heat insulation layer It is: 50% of corundum hollow spheres, 50% of α-Al ₂ O ₃ micropowder, and 33% of the mass percentage content of α-Al ₂ O ₃ micropowder as a phosphoric acid solution binder.

The preparation process comprises the following steps:

(1) Batching: The batching process of the heavy support layer is to mix the powder not larger than 325 mesh in proportion and mix it evenly in the ball mill, and then add the mixed powder after the rest of the aggregate particles and the binder are mixed evenly , stirred for 10-30 minutes and then set aside; the batching process of the high-strength and light-weight heat insulation layer is to mix corundum hollow balls with phosphoric acid solution in proportion, and then add α-Al ₂ O ₃ in proportion to stir for 10-30 minutes and set aside.

(2) Molding: After the batching is completed, the size ratio between the heavy support layer and the light heat insulation layer is determined according to the use position, wear rate and service life of the material, and the material cavity of the molding mold is separated into parts according to the ratio. The two parts are drawn out after feeding, and formed by vibrating pressure or machine pressing.

(3) Firing: The shaped green body is taken out and dried at 80-150°C, then loaded into a kiln and kept at 1600°C for 3-8 hours for firing.

Claims (4)

1. corundum hollow sphere structure heat-insulating integrated composite brick, it is characterized in that: the heavy supporting layer that comprises the compact high-alumina alumina, and be the light heat insulation layer of aglite with the corundum bollow ball, be composited by both, the length dimension ratio of heavy supporting layer and light heat insulation layer is 1～5: 2～1.

2. by the preparation method of the described a kind of corundum hollow sphere structure heat-insulating integrated composite brick of claim 1, it is characterized in that:

The proportioning raw materials of A, heavy supporting layer and light heat insulation layer is as follows:

One, in the compact high-alumina alumina heavy supporting layer, the quality percentage composition of each component is:

1～3mm alumine 35～45%; Less than mm alumine 20～35%; Be not more than 325 height of eye bauxitic clays 20～35%; Clay powder 5～10%; Add wedding agent 3～5%;

Two, light heat insulation layer is for being the light heat insulation layer of aglite with the corundum bollow ball, and its technical indicator and content ratio are as follows:

In the corundum bollow ball high-strength light thermofin, Al ₂O ₃Quality percentage composition＞92%, particle diameter is 0.2～5mm, natural tap density 0.6～0.9g/cm ³The quality percentage composition of each component is: corundum bollow ball 34～60%, α-Al ₂O ₃Micro mist 40～66%, to add wedding agent be α-Al ₂O ₃30～35% of micro mist quality percentage composition;

The preparation method of B, corundum hollow sphere structure heat-insulating integrated composite brick:

(1) heavy supporting layer preparation: will be not more than 325 powder materials earlier and prepare the back in proportion and in ball mill, mix, and mix the powder that the back adding mixes at all the other particless of aggregates and wedding agent again, and stir standby after 10～30 minutes;

(2) light heat insulation layer preparation: with the corundum bollow ball is aglite, and aglite is mixed with wedding agent in proportion, add in proportion then powder stir 10～30 minutes standby;

(3) moulding: finish after the batching, with dividing plate the material chamber of forming mould is divided into two portions, the length dimension ratio of heavy supporting layer and light heat insulation layer is 1～5: 2～1, and reinforced back is extracted dividing plate out, adopts vibrations pressurization or mechanical pressing;

(4) burn till: the loading of kiln after 80～150 ℃ of oven dry of the base substrate taking-up after the moulding was burnt till in 1500～1650 ℃ of insulations in 3～8 hours.

3. the preparation method of a kind of corundum hollow sphere structure heat-insulating integrated composite brick according to claim 1, it is characterized in that: in the described light heat insulation layer, wedding agent is phosphoric acid solution or phosphate dihydrogen aluminum solution.

4. the preparation method of a kind of corundum hollow sphere structure heat-insulating integrated composite brick according to claim 1, it is characterized in that: in the heavy supporting layer of described fine and close magnesium high alumina, wedding agent is organic bond or phosphoric acid solution or phosphate dihydrogen aluminum solution.