Abandoned molding sand based mullite light heat insulating bricks and preparation method thereof

A technology of waste molding sand and light heat insulation, which is applied in the field of mullite light heat insulation refractory materials, can solve the problems of unguaranteed actual use performance, segregation and settlement of outgoing wires, and reducing the strength of the green body, etc., and is conducive to thermal shock. Stable performance, reduced raw material cost, high compressive strength effect

Active Publication Date: 2012-08-15
WUHAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the poor bleeding of the molding sand, it will lead to problems such as poor bonding between the castable aggregate and the powder, segregation and settlement of the outgoing line, which will greatly reduce the strength of the green body, which will lead to the failure of its actual performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A mullite lightweight heat-insulating brick based on waste molding sand and a preparation method thereof. First mix 40-50wt% waste molding sand fine powder, 20-30wt% waste molding sand particles and 20-30wt% super-grade bauxite as raw materials, then add 11-14wt% plastic clay, 8-10wt% Kyanite, 0.15~0.2wt% sodium carboxymethylcellulose, 0.1~0.15wt% sodium hexametaphosphate, 3~4wt% dextrin, 20~30wt% sawn wood and 25~35wt% water , mix evenly, trap the material for 5-8 hours, extrude, dry naturally, bake at 110°C for 10-12 hours, heat up to 1200-1250°C, and keep warm for 6-8 hours.

[0023] The bulk density of mullite lightweight bricks based on waste molding sand prepared in this example is 0.8~1.2g / cm 3 , the thermal conductivity is 0.21~0.32w / (m.k)(350℃), the compressive strength is 4.8~8.5Mpa, and the change rate of reburning line is -0.4~-0.6%(1400℃×12h).

Embodiment 2

[0025] A mullite lightweight heat-insulating brick based on waste molding sand and a preparation method thereof. First mix 50-55wt% waste molding sand fine powder, 15-20wt% waste molding sand particles and 30-35wt% super-grade bauxite as raw materials, then add 8-11wt% plastic clay, 7-9wt% Kyanite, 0.3~0.5wt% sodium tripolyphosphate, 2~3wt% dextrin, 5~15wt% sawn wood and 15~25wt% water, mix evenly, keep the material for 3~6 hours, half Dry machine press molding, dry naturally, bake at 110°C for 8-10 hours, heat up to 1250-1300°C, and keep warm for 6-8 hours.

[0026] The bulk density of mullite lightweight bricks based on waste molding sand prepared in this example is 1.2~1.5g / cm 3 , the thermal conductivity is 0.29~0.40w / (m.k)(600℃), the compressive strength is 8.9~16.8Mpa, and the change rate of reburning line is -0.2~-0.35%(1400℃×12h).

Embodiment 3

[0028] A mullite lightweight heat-insulating brick based on waste molding sand and a preparation method thereof. First mix 55-60wt% waste molding sand fine powder, 10-20wt% waste molding sand particles and 20-35wt% α-Al 2 o 3 To mix the raw materials, add 7~9wt% plastic clay, 5~7wt% kyanite, 0.1~0.3wt% sodium hexametaphosphate, 2~3wt% dextrin, 15~20wt% Mix sawn wood and 25-32wt% water evenly, trap the material for 6-9 hours, extrude, dry naturally, bake at 110°C for 10-12 hours, heat up to 1300-1350°C, and keep warm for 4-6 hours.

[0029] The bulk density of the mullite lightweight brick based on waste molding sand prepared in this example is 0.9~1.2g / cm 3 , the thermal conductivity is 0.26~0.35w / (m.k)(600℃), the compressive strength is 6.6~13.2Mpa, and the change rate of reburning line is -0.3~-0.4%(1400℃×12h).

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Abstract

The invention relates to abandoned molding sand based mullite light heat insulating bricks and a preparation method thereof, wherein the preparation method in the technical scheme comprises the following steps: firstly mixing 45-80wt% of abandoned molded sand and 20-55wt% of special-grade alumina or alpha-Al2O3 as raw materials; then additionally adding 2-10wt% of kyanite, 5-15wt% of plasticine, 5-30wt% of pore-forming agent, 0.5-4wt% of plasticizer, 0.1-0.5wt% of bonding agent and 15-35wt% of water of the raw materials, mixing uniformly, aging for 3-10 hours, molding, drying naturally, baking at 110 DEG C for 8-12 hours, warming to 1200-1450 DEG C, and keeping the temperature for 2.5-10 hours. The abandoned molding sand based mullite light heat insulating bricks and the preparation method thereof provided by the invention have the advantages of low production cost, simple technology, energy conservation and environment friendliness and easiness for large scale production, and the prepared mullite light heat insulating bricks not only have high pressure-resistant intensity, good heat shock stability, low volume density and small heat conduction coefficient, and also have wide social and economic value.

Description

technical field [0001] The invention belongs to the technical field of mullite lightweight heat-insulating refractory materials, and in particular relates to a mullite light-weight heat-insulating brick based on waste molding sand and a preparation method thereof. Background technique [0002] Molding sand is a material used for molding in casting. It is generally made by mixing molding materials such as raw sand for casting, molding sand binder and auxiliary additives in a certain proportion. Worldwide, more than 70% of castings are produced by sand casting. Generally speaking, 1 to 1.3 tons of waste sand is produced for every ton of qualified castings produced. The amount of waste sand produced in my country is more than 30 million tons per year. At present, there are not many treatment methods for precision casting waste sand. The general treatment method is Stack or landfill. Not only seriously pollute the environment, but also a waste of resources. How to turn these f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/66C04B35/185
Inventor 李远兵向若飞杨力刘芳李亚伟范志辉赵雷袁添翼
Owner WUHAN UNIV OF SCI & TECH
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