CN1303036C

CN1303036C - Process for preparing high strength corundum refractory material by low temperature sintering

Info

Publication number: CN1303036C
Application number: CNB2004100605157A
Authority: CN
Inventors: 杨道媛; 关少康; 贾晓林; 封鉴秋; 张海军
Original assignee: Zhengzhou University
Current assignee: Zhengzhou University
Priority date: 2004-09-15
Filing date: 2004-09-15
Publication date: 2007-03-07
Anticipated expiration: 2024-09-15
Also published as: CN1587189A

Abstract

The present invention provides a method for preparing a high-strength corundum fire resisting material by a low-temperature sintering process. In the method for preparing a high-strength corundum fire resisting material by a low-temperature sintering process, corundum raw materials which are particularly electric melting white corundum aggregate and powder are used as main raw materials, silicon ash (a smoke waste gas recovery object in an iron alloy factory) having the advantages of small granularity, large activity, rich good supply and low price is added on the basis of corundum multi-stage granule mixing materials and is used as a sintering aid, and after a mixing process and a forming process, the high-strength corundum fire resisting material is prepared by the sintering process under low temperature (1300 DEG C to 1550 DEG C). The method for preparing a high-strength corundum fire resisting material by a low-temperature sintering process can produce the product of the good-quality corundum fire resisting material and can also considerably save energy source and reduce production cost, the high-strength corundum fire resisting material has the advantages of low sintering temperature, large strength, high temperature resistance and corrosion resistance, and the high-strength corundum fire resisting material can be used as the advanced fire resisting materials and the ceramic wares of the high temperature furnaces of industries, such as metallurgy, construction materials, chemical industries, ceramics, etc.

Description

Low-temperature sintering high strength refractory corundum material preparation method

Technical field:

The invention belongs to pottery, refractory materials preparing technical field, being specifically related to a kind of is the preparation method of the low-temperature sintering high strength refractory corundum material of main raw material by fused white corundum aggregate and powder.

Background technology:

Corundum refractory has excellent mechanical property, and it is high temperature resistant, corrosion-resistant, wear-resistant, be develop the earliest, the present bigger a kind of high grade refractory of turnout, be mainly used in field high temperature kiln key position liners such as iron and steel, chemical industry, pottery, machinery, yet the sintering temperature height of corundum based refractory materials, usually more than 1600 ℃, production cost is high, has influenced the widespread use of this material to a certain extent.

In order to reduce the firing temperature of corundum refractory, the method that adopts mainly contains usually:

(1) adds boric acid or B ₂O ₃Method: after 1550 ℃ of calcinings, make Na ₂O generates Sodium Tetraborate and volatilizees, and adds B ₂O ₃To SiO ₂Content aluminum oxide refining effect high and that weave construction is perfect is very effective, but because aluminum oxide forms the coarse-grain structure, therefore density, mechanical property and the dielectric properties of special refractories is all decreased;

(2) MgCl ₂Not only can remove the Na in the aluminum oxide ₂O, it still burns till the desired crystal formation of corundum ceramic goods and transforms conditioning agent, and does not need to adopt the auxiliary process measure.This method be widely used in produce chemical pure, under vacuum fine and close extraordinary corundum ceramic goods, the corundum grog of Sheng Chaning in this way can the production chemical ingredients, mechanical property and the extra high corundum products of density, sintering temperature is 1500-1620 ℃.Add appropriate MgO and also can promote the sintering of corundum based refractory materials, and improve the intensity of burning till the back material.

(3) if add TiO ₂Or MnCO ₃Though the corundum refractory calcining temperature can be reduced to 1600 ℃, these two kinds of additives can both make the crystal grain growth grow up, and significantly reduce the physical strength of material, make material painted simultaneously.

(4) add Cr ₂O ₃Or ZrO ₂1600 ℃ of corundum based refractory materials burn till after, have excellent high-temperature intensity and thermal shock resistance.

According to putting down in writing in the CSTAD, the heavy oil pressurized-gasification furnace corundum products project of Refractory Material Factory, Xinxiang City's evaluation in 1993 is characterized in adding an amount of alumina powder in batching, and adopts phosphate binders, burns till at 1550-1610 ℃.The high-purity corundum brick of Luoyang Institute of Refractories Research's evaluation in 1992, be characterized in adopting showing under two kinds of high temperature that different electric smelting and the alundums that burn till contraction are main raw material, and add part active oxidation aluminium powder, multiple stage material compounding, two-sided extrusion forming, high temperature are burnt till and are made.

Application number is 00123761.6 patent, a kind of high-purity low silicon and low iron corundum products is disclosed, being characterized in removing in batching fused corundom, sintered alumina fine powder and wedding agent adds into micro-calcareous material as sintering aid, improved the sintering situation of brick, make brick burn till the good sintering of realization under the temperature low, the high-purity corundum brick cold crushing strength of making is about 110MPa.

Application number is 99123977.6 patent, adds the kaolin fine powder relatively largely in matrix, thereby prepares corundum-mullite product.

Application number is the patent of 88104671.X, be characterized in sintered sheet corundum crystalline particle moulding in prefabricated model of all having cleavage surface by numerous, then through 1500 ℃ of sintering, make and assemble mutually between the particle and combine, its combination makes that the cleavage surface of these accumulative plate crystal granules is parallel to each other substantially, thereby prepares high flexural strength sintered alumina article.

The problem that the method for putting down in writing in the above-mentioned document for preparing corundum refractory exists is, firing temperature is higher, and energy consumption is big, and the cost height has influenced the production of corundum refractory and being extensive use of in hot industry thereof to a certain extent.

Summary of the invention:

The purpose of this invention is to provide a kind of silicon ash that utilizes cheapness as sintering aid, prepare the method for high strength refractory corundum material at a lower temperature,, cut down the consumption of energy and preparation cost, be beneficial to industry manufacturing to reduce firing temperature.

Principle of the present invention is to add the proper amount of silicon ash in the corundum raw material, utilizes the short nodulizing of the higher silicon ash of sintering activity under the high temperature, makes the corundum material Fast Sintering, thereby obtains low sintering high-strength corundum material.If silicon ash add-on very little, in temperature of the present invention, material does not reach good sintering state, and intensity is lower.If but silicon ash add-on is excessive, the interior mullite synthesizing of material is mutually too much in the sintering process, and volumetric expansion is bigger, influences the performance of product.Therefore, the add-on of silicon ash should be suitable.

Realize that the object of the invention technical scheme is:

The preparation method of low-temperature sintering high strength refractory corundum material comprises that mainly raw material mixes, adds wedding agent, mixing, shaping and drying, technological process such as burns till, and is characterized in that:

A. with electric smelting or alundum raw material crushing or be ground into 3-1mm, 1-0.088mm, the particle of three kinds of granularities below the 0.088mm;

B. make sintering aid with silicon ash or monox nanometer powder, mix in the corundum in granules material below massfraction 1-9% (adding) ratio and the 0.088mm, as the matrix material;

C. the corundum in granules material with 3-1mm, 1-0.088mm mixes;

D. add wedding agent in the c compound, after mixing, add the matrix material that b obtains, remix is even, makes pug

E. the pug that d is made is put into pressing machine, is pressed into base substrate under 70-200MPa pressure, and drying was burnt till 2-8 hour under 1300-1550 ℃ of temperature then, and cooling is come out of the stove, and promptly makes product.

Among the above-mentioned preparation method, 3-1mm, 1-0.088mm, the following three kinds of different corundum raw material ratio of mixture of 0.088mm are 40-50%: 10-20%: 30-40%, are preferably 45: 15: 40; The add-on of wedding agent is the 3-15% of corundum raw material.

Among the above-mentioned preparation method, used corundum raw material is a kind of in fused white corundum, plate diamond spar, brown corundum, grey corundum, bauxite corundum, the alundum; Wedding agent is one or more in industry sulphate pulp waste liquid, polyvinyl alcohol, dextrin, the xylogen.

With the corundum material that the inventive method makes, thing phase composite: corundum 〉=98%, physical and chemical performance: Al ₂O ₃〉=90%, volume density 2.8-3.2g/cm ³, apparent porosity≤25%, strength at normal temperature 〉=20MPa, cold crushing strength 〉=80MPa.

Compared with prior art, the invention has the advantages that:

1, adopts the silicon ash as sintering aid, reduced the firing temperature of material, reduced preparation cost.

2, Zhi Bei strength of materials height, the work-ing life that helps improving material.

3, silicon ash source is abundant, cheap, and short nodulizing is obvious.

Embodiment

Embodiment 1:

The employed main raw material of present embodiment is:

(1) fused white corundum: chemical ingredients (massfraction) is Al ₂O ₃〉=98%, granularity is following three kinds of 3-1mm, 1-0.088mm, 0.088mm;

(2) silicon ash: select SiO for use ₂〉=91%.

Raw material of the present invention and silicon ash proportioning are as shown in the table:

Raw material	Fused white corundum		The silicon ash
Raw material	Fused white corundum		The silicon ash		Grain size proportion (weight fraction %)	3-1mm 45	1-0.088mm 15	＜0.088mm 40	0.1μm 4

Take by weighing various fused white corundum raw materials in ratio shown in the last table, wherein adding the silicon ash is 4%.Earlier the following fused white corundum particulate material of 0.088mm and silicon ash are mixed the matrix material; Again with 3-1mm, the Preblend of 1-0.088mm particulate, and add 3% polyvinyl alcohol wedding agent and put into mixer and mix, add the matrix material at last and in mixer, mix 5 minutes to evenly promptly making pug; Pug is put into pressing machine go out 25 * 25 * 125mm base substrate at the 80MPa forming under the pressure; Base substrate was 110 ℃ of dryings 4 hours; 1350 ℃ * 6h burns till in electric furnace then, and cooling is come out of the stove, and makes corundum material.

The corundum material performance that makes is as follows: Al ₂O ₃〉=90%, volume density 2.9g/cm ³, apparent porosity 25%, strength at normal temperature 33.4MPa, cold crushing strength 105MPa.

Embodiment 2:

The employing fused brown corundum is a particulate material, and proportioning raw materials and preparation technology go out 25 * 25 * 125mm base substrate with embodiment 1 at the 120MPa forming under the pressure; Base substrate was 110 ℃ of dryings 4 hours; In electric furnace, burn till 1550 ℃ * 6h.The corundum material performance that makes is as follows: principal crystalline phase is the corundum phase, Al ₂O ₃〉=90%, volume density 3.0g/cm ³, apparent porosity 23%, strength at normal temperature 35MPa, the material mineral facies consist of more purified corundum phase.

Embodiment 3:

Add 9% silicon ash in batching, wedding agent adopts lignosulfite, and other raw materials and proportioning and preparation technology go out 25 * 25 * 125mm base substrate with embodiment 1 at the 120MPa forming under the pressure; Base substrate was 110 ℃ of dryings 4 hours; In electric furnace, burn till 1350 ℃ * 6h.The corundum material performance that makes is as follows: principal crystalline phase is the corundum phase, Al ₂O ₃〉=90%, volume density 3.1g/cm ³, apparent porosity 19%, strength at normal temperature 45MPa, the material mineral facies consist of corundum mutually with the trace mullite mutually.

Claims

1. A method for preparing a low-temperature sintered high-strength corundum refractory material, mainly including raw material mixing, adding a binder, molding, drying, and firing processes, characterized in that:

a. Crushing or pulverizing the fused or sintered corundum raw materials into particles of three particle sizes below 3-1mm, 1-0.088mm, and 0.088mm, the mixing ratio of which is 40-50%: 10-20%: 30-40%;

b. Use silica fume or silicon oxide nanopowder as a sintering aid, and mix it evenly with corundum particles below 0.088mm in a mass fraction of 1-9% as a base material;

c. Mix 3-1mm and 1-0.088mm corundum pellets evenly;

d. Add a binder to the mixture of c and mix evenly, then add the base material of b, mix evenly, and make mud;

e. Put the mud prepared in d into a press, press it into a green body under a pressure of 70-200MPa, dry it, and then burn it at a temperature of 1300-1550°C for 2-8 hours, cool it, and take it out of the furnace to obtain product.

2. According to the preparation method of low-temperature sintered high-strength corundum refractory material according to claim 1, it is characterized in that: the mixing ratio of three different corundum raw materials below 3-1mm, 1-0.088mm, and 0.088mm is 45%: 15%: 40%.

3. The method for preparing low-temperature sintered high-strength corundum refractory material according to claim 1, characterized in that: the amount of the binder added is 3-15% of the corundum raw material.

4. According to the preparation method of low-temperature sintered high-strength corundum refractory material according to claim 1, it is characterized in that: said corundum raw material is fused white corundum, tabular corundum, brown corundum, gray corundum, bauxite corundum, sintered corundum One of.

5. According to the preparation method of low-temperature sintered high-strength corundum refractory material according to claim 1, it is characterized in that: said binder is one or more of sulfurous acid pulp waste liquid, polyvinyl alcohol, dextrin, and lignin kind.