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Method for preparing sintered corundum

A sintered corundum and calcination technology, which is applied in the field of refractory material production, can solve the problems of long holding time, high energy consumption, and high raw material requirements, and achieve the effects of reduced holding time, reduced energy consumption, and low raw material requirements

Inactive Publication Date: 2009-12-16
CHINA UNIV OF GEOSCIENCES (WUHAN) +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, there are still some problems in the current method of producing sintered corundum: (1) the holding time is long, usually more than 10 hours, and consumes a lot of energy; (2) the firing temperature is high, usually higher than 1650°C; (3) the process is complicated, Large investment; (4) High requirements for raw materials, some of which use fused corundum, industrial alumina, imported industrial γ-Al 2 o 3 etc. as raw materials, the cost is high
However, the use of alkali metal or alkaline earth metal compounds as sintering aids will affect the high-temperature performance of the material and reduce the scope of use of the material; adding silicon powder or silicon dioxide fine powder will reduce the aluminum content of the corundum material, which is not suitable for corundum with high aluminum content. production

Method used

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  • Method for preparing sintered corundum
  • Method for preparing sintered corundum
  • Method for preparing sintered corundum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Take Shanxi Jiexiu high-alumina bauxite powder 1000g, add MnO respectively equivalent to 5‰ of high-alumina bauxite powder weight 2 , 5‰ of natural flake graphite powder and 5‰ of carboxymethyl cellulose, which are mixed uniformly to obtain a batch, then add 200ml of water to the batch, after mixing, the mixture is extruded into strips (this The extruded strip material obtained in the embodiment has a diameter of 20mm and a length of 100mm), after drying at 160°C for 2 hours, put it into a silicon-molybdenum rod box-type electric furnace, heat up to 1550°C at a speed of 5°C / min, and heat-preserve and calcinate for 1 hours to get the product.

[0033] Carry out XRD analysis on the product, such as figure 1 As shown, the main crystal phase of the obtained product is corundum, and the content is greater than 93%. The volume density of the product measured by XQK-01 / 02 apparent pore volume density tester (Luoyang Refractory Research Institute Instrument Manufacturing Comp...

Embodiment 2

[0035] Take Shanxi Jiexiu high-alumina bauxite powder 1000g, add MnO which is equivalent to 6‰ of high-alumina bauxite powder weight 2 , 4‰ of natural flake graphite powder and 5‰ of carboxymethyl cellulose, mixed evenly to obtain the batch material, then added 240ml of water to the batch material, after mixing, the mixture was extruded into strips, at 120 ° C After drying for 4 hours, put it into a silicon-molybdenum rod box-type electric furnace, raise the temperature to 1550°C at a rate of 5°C / min, and heat-preserve and calcinate for 1 hour to obtain the product.

[0036] Carry out XRD analysis on the product, such as figure 2 As shown, the main crystal phase of the obtained product is corundum, and the content is greater than 93%. Tested in the same way as in Example 1, the bulk density of the sintered corundum obtained in this example is 3.31g / cm 3 , the porosity is 2.58%, the water absorption is 0.78%, and the refractoriness is >1790°C.

Embodiment 3

[0038] Take Shanxi Jiexiu high-alumina bauxite powder 1000g, add MnO respectively equivalent to the weight of high-alumina bauxite powder 4‰ 2 , 6‰ of natural flake graphite powder and 5‰ of carboxymethyl cellulose, mixed evenly to obtain the batch material, then added 180ml of water to the batch material, after mixing, the mixture was extruded into strips, at 100 ° C After drying for 6 hours, put it into a silicon-molybdenum bar box-type electric furnace, raise the temperature to 1550°C at a rate of 5°C / min, and heat-preserve and calcinate for 1 hour to obtain the product.

[0039] Carry out XRD analysis on the product, such as image 3 As shown, the main crystal phase of the obtained product is corundum, and the content is greater than 93%. Tested in the same manner as in Example 1, the bulk density of the sintered corundum obtained in this example is 3.30 g / cm 3 , the porosity is 3.17%, the water absorption is 0.96%, and the refractoriness is >1790°C.

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Abstract

The invention discloses a method for preparing sintered corundum, including the following steps: natural high-aluminium alumina powder, additive and binder are uniformly mixed to obtain a batch material; the grain diameter of the natural high-aluminium alumina powder is less than or equal to 0.074mm, and according to weight percentage, the content of Al2O3 is not lower than 77 percent; the additive is the mixture of MnO2 and natural flaky graphite powder, the grain diameter of the natural flaky graphite powder is less than or equal to 0.074mm, according to weight percentage the content of carbon in the natural flaky graphite powder is not lower than 85 percent, and the addition quantities of MnO2 and natural flaky graphite powder are respectively 0.4 to 0.8 percent of the weight of the natural high-aluminium alumina powder; and the binder is carboxymethylcellulose, and the addition quantity thereof is 0.3 to 0.8 percent of the weight of the natural high-aluminium alumina powder. The mixture formed by proportionally and uniformly mixing the batch material with water is extruded into the shape of a strip and is dried to be molded, temperature is slowly increased to 1550 to 1600 DEG C, and the step of thorough heat preservation and calcination is carried out, thereby obtaining the sintered corundum. The method of the invention has the advantages that the technology is simple, the firing temperature is reduced to 1550 DEG C, the energy consumption is low, and the performance of the obtained product is excellent.

Description

technical field [0001] The invention relates to a method for preparing sintered corundum, in particular to a method for producing sintered corundum by using high-alumina bauxite with a loose structure that cannot be directly calcined as a raw material, and belongs to the field of refractory material production. Background technique [0002] The scientific name of bauxite ore is bauxite ore and bauxite. Its composition is extremely complex, and it is a general term for a variety of hydrous alumina ores of very different geological origins, such as boehmite, diaspore and gibbsite. [0003] Corundum (a-Al 2 o 3 ) is Al 2 o 3 a crystal form. There are many types of corundum, which can be divided into light-burned corundum (1350-1550°C), sintered corundum (1750-1950°C) and fused corundum according to the production method; according to the crystal form, it can be divided into tabular corundum, columnar corundum, granular corundum, etc. ;According to the appearance color, it...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/66C04B35/622C04B35/63C04B35/10
Inventor 严春杰陈洁渝余洪杰万为敏蔡建王铎
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)
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