Lightweight micro-closed-pore corundum composite refractory, method for preparing the same

Abstract

A lightweight micro-closed-pore corundum composite refractory and a method preparing the same, wherein raw materials of the refractory comprise 95-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-5 parts by weight of dolomite clinker; and additives of the refractory comprise 2-15 parts by weight of nano alumina sol, 5-15 parts by weight of a carbohydrate polymer, and 30-50 parts by weight of an organic alcohol. and the lightweight micro-closed-pore corundum composite refractory is prepared by: mixing and wet grinding the raw materials and the additives to obtain a slurry; placing the slurry in a mold, keeping the mold at 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, then demolding; drying a demolded green body at 110-200 C. for 24-36 hours, and keeping the green body at 1800-2000 C. for 2-5 hours. A method preparing a lightweight micro-closed-pore corundum composite refractory is also provided. The lightweight micro-closed-pore corundum composite refractory of the present invention has characteristics of low bulk density, small average pore size, high closed porosity, low thermal conductivity, strong thermal shock resistance, abrasion resistance and slag resistance.

Claims

1. A lightweight micro-closed-pore corundum composite refractory, comprising: raw materials of the refractory comprise 95-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-5 parts by weight of dolomite clinker, and additives of the refractory comprise 2-15 parts by weight of nano alumina sol, 5-15 parts by weight of carbohydrate polymer, and 30-50 parts by weight of organic alcohol, the lightweight micro-closed-pore corundum composite refractory is prepared by: mixing and wet grinding the raw materials and the additives to obtain a slurry; placing the slurry in a mold, keeping the mold at 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, then demolding; drying a demolded green body at 110-200 C. for 24-36 hours, and keeping the green body at 1800-2000 C. for 2-5 hours, and the -Al.sub.2O.sub.3 micro-powder has an Al.sub.2O.sub.3 content of >99.2% by weight and a particle size D50 of 0.5-3 m.

2. The lightweight micro-closed-pore corundum composite refractory of claim 1, wherein the dolomite clinker has a total content of MgO and CaO of >99 wt % and a particle size D50 of 2-7 m.

3. The lightweight micro-closed-pore corundum composite refractory of claim 1, wherein the nano-alumina sol has a dispersed phase content of >25 wt % and an average particle size of 20-50 nm.

4. The lightweight micro-closed-pore corundum composite refractory of claim 1, wherein the carbohydrate polymer is one or two or more mixtures of dextrin, starch and chitin.

5. The lightweight micro-closed-pore corundum composite refractory of claim 1, wherein the organic alcohol is one or two or more mixtures of ethanol, polyvinyl alcohol, and tert-butyl alcohol.

6. The lightweight micro-closed-pore corundum composite refractory of claim 1, wherein a planetary ball mill is used for the wet grinding.

7. The lightweight micro-closed-pore corundum composite refractory of claim 6, wherein a grinding ball of the planetary ball mill is a corundum ball.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) The present invention will be further described with reference to the following embodiments.

Raw Materials

(2) The -Al.sub.2O.sub.3 micro powder has an Al.sub.2O.sub.3 content of >99.2 wt % and a particle size D50 of 0.5-3 m.

(3) The dolomite clinker has a total content of MgO and CaO of >99 wt % and a particle size D50 of 2-7 m.

(4) The nano-alumina sol has a dispersed phase content of >25 wt % and an average particle size of 20-50 nm.

(5) The grinding ball of the planetary ball mill is a corundum ball.

Example 1: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(6) The raw materials of the refractory comprise 95-97 parts by weight of -Al.sub.2O.sub.3 micro-powder and 3-5 parts by weight of dolomite clinker; the additives of the refractory comprise 12-15 parts by weight of nano alumina sol, 10-15 parts by weight of a dextrin, and 30-40 parts by weight of ethanol; and the lightweight micro-closed-pore corundum composite refractory is prepared by: mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.5-1 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 110-160 C. for 24-30 hours, and keeping the green body at 1900-2000 C. for 2-4 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(7) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.75-2.85 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 55%, and an average pore size of 0.1-0.3 m.

Example 2: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(8) The raw materials of the refractory comprise 95-97 parts by weight of -Al.sub.2O.sub.3 micro-powder and 3-5 parts by weight of dolomite clinker; the additives of the refractory comprise 12-15 parts by weight of nano alumina sol, 5-10 parts by weight of starch, and 30-40 parts by weight of polyvinyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.1-0.6 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 150-200 C. for 30-36 hours, and keeping the green body at 1800-1900 C. for 3-5 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(9) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.80-2.88 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 57%, and an average pore size of 0.2-0.35 m.

Example 3: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(10) The raw materials of the refractory comprise 95-97 parts by weight of -Al.sub.2O.sub.3 micro-powder and 3-5 parts by weight of dolomite clinker; the additives of the refractory comprise 8-12 parts by weight of nano alumina sol, 10-15 parts by weight of chitin, and 30-40 parts by weight of tert-butyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.5-1 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 110-160 C. for 24-30 hours, and keeping the green body at 1900-2000 C. for 2-4 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(11) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.80-2.85 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 56%, and an average pore size of 0.2-0.4 m.

Example 4: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(12) The raw materials of the refractory comprise 95-97 parts by weight of -Al.sub.2O.sub.3 micro-powder and 3-5 parts by weight of dolomite clinker; the additives of the refractory comprise 8-12 parts by weight of nano alumina sol, 5-10 parts by weight of mixture of dextrin and starch, and 40-50 parts by weight of mixture of ethanol and polyvinyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.1-0.6 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 150-200 C. for 30-36 hours, and keeping the green body at 1800-1900 C. for 3-5 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(13) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.90-2.95 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 57%, and an average pore size of 0.2-0.4 m.

Example 5: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(14) The raw materials of the refractory comprise 97-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-3 parts by weight of dolomite clinker; the additives of the refractory comprise 5-8 parts by weight of nano alumina sol, 10-15 parts by weight of mixture of dextrin and chitin, and 30-40 parts by weight of mixture of ethanol and tert-butyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.5-1 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 110-160 C. for 24-30 hours, and keeping the green body at 1900-2000 C. for 2-4 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(15) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.85-2.94 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 55%, and an average pore size of 0.25-0.45 m.

Example 6: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(16) The raw materials of the refractory comprise 97-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-3 parts by weight of dolomite clinker; the additives of the refractory comprise 5-8 parts by weight of nano alumina sol, 5-10 parts by weight of mixture of starch and chitin, and 40-50 parts by weight of mixture of polyvinyl alcohol and tert-butyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.1-0.6 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 150-200 C. for 30-36 hours, and keeping the green body at 1800-1900 C. for 3-5 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(17) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.88-3.00 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 56%, and an average pore size of 0.25-0.5 m.

Example 7: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(18) The raw materials of the refractory comprise 97-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-3 parts by weight of dolomite clinker; the additives of the refractory comprise 2-5 parts by weight of nano alumina sol, 10-15 parts by weight of mixture of dextrin, starch and chitin, and 30-40 parts by weight of mixture of ethanol, polyvinyl alcohol and tert-butyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.5-1 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 110-160 C. for 24-30 hours, and keeping the green body at 1900-2000 C. for 2-4 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(19) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.90-3.00 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 55%, and an average pore size of 0.3-0.45 m.

Example 8: Preparation for Lightweight Micro-Closed-Pore Corundum Composite Refractory

(20) The raw materials of the refractory comprise 97-99 parts by weight of -Al.sub.2O.sub.3 micro-powder and 1-3 parts by weight of dolomite clinker; the additives of the refractory comprise 2-5 parts by weight of nano alumina sol, 5-10 parts by weight of mixture of dextrin, starch and chitin, and 40-50 parts by weight of mixture of ethanol, polyvinyl alcohol and tert-butyl alcohol; mixing and wet-grinding the raw materials and the additives with planetary ball mill for 0.1-0.6 hour to obtain a slurry; placing the slurry in a mold, keeping the mold at room temperature of 15-25 C. for 6-12 hours and then keeping the mold at 60-90 C. for 6-12 hours, and demolding; drying a demolded green body at 150-200 C. for 30-36 hours, and keeping the green body at 1800-1900 C. for 3-5 hours, then the lightweight micro-closed-pore corundum composite refractory is obtained.

(21) It has been proved by experiments that the lightweight micro-closed pore corundum composite refractory prepared by this example has a bulk density of 2.95-3.05 g/cm.sup.3, a ratio of closed porosity to total porosity of more than 55%, and an average pore size of 0.3-0.5 m.