Method for recycling waste silicon nitride combined with silicon carbide bricks produced by aluminum electrolytic cells

A technology of silicon carbide bricks and waste silicon nitride, which is applied in the fields of resource regeneration and environmental protection, can solve problems such as nitrogen increase in molten steel, impact on clean steel quality, secondary pollution, etc., achieve low cost, realize utilization value, and completely separate Effect

Active Publication Date: 2022-07-26
上海彭浦特种耐火材料厂有限公司 +3
View PDF8 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this invention realizes the recycling of waste materials, the disadvantage of this method is that there are still environmental problems such as secondary pollution caused by sewage and dust, and there are also environmental problems such as dust after crushing and crushing.
That is, the N content is about 8~11%, which will lead to nitrogen increase in molten steel, therefore, it will have an adverse effect on the quality of clean steel with low nitrogen content

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for recycling waste silicon nitride combined with silicon carbide bricks produced by aluminum electrolytic cells

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The used silicon carbide bricks come from an aluminum factory

[0031] Weigh 15kg of the used silicon carbide, open the upper cover 4 of the furnace, and put 15kg of the used silicon carbide into it. Then close the lid. Then turn on the vacuum pump 1 to evacuate, so that the vacuum degree is 1 Torr. Turn on the heating power, heat to 1250 ° C, keep the temperature for 6 h, and end when no gas is released. After cooling down, open the lower lid of the furnace and let out the residue from the furnace, while removing the cooled electrolyte from the cooling chamber. It is analyzed and the results are shown in the following table:

[0032] AlF 3

[0033] Therefore, the separation effect is good. The yield rate reached 99%. The recovered electrolyte can be returned to the aluminum plant for reuse, while the recovered silicon carbide can be used as a raw material for the production of silicon carbide products or as a raw material for metallurgical deoxidizer...

Embodiment 2

[0035] The used silicon carbide bricks come from an aluminum factory

[0036] Weigh 20kg of used silicon carbide bricks, open the upper cover 4 of the furnace, and put 20kg of used silicon carbide bricks in. Then close the lid. Then turn on the vacuum pump 1 to evacuate, so that the vacuum degree is 1 Torr. Turn on the heating power, heat to 1300 ° C, keep the temperature for 6 h, and end when no gas is released. After cooling, open the lower lid of the stove and let the residue out of the stove. At the same time, the cooled electrolyte in the cooling chamber was taken out. Analyze it. The results are shown in the table below:

[0037] AlF 3

[0038] Therefore, the separation effect is good. The yield rate reached 99%. The recovered electrolyte can be returned to the aluminum plant for reuse, while the recovered silicon carbide can be used as a raw material for the production of silicon carbide products or as a raw material for metallurgical deoxidizers. ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
particle sizeaaaaaaaaaa
process yieldaaaaaaaaaa
Login to view more

Abstract

The invention relates to a method for recycling waste silicon nitride combined with silicon carbide bricks produced by an aluminum electrolytic cell, which is characterized in that the waste silicon nitride combined with silicon carbide bricks produced by an aluminum electrolytic cell is collected and placed in a vacuum heating furnace , vacuum heating, which uses waste silicon nitride to combine the electrolyte vaporization reaction and evaporation in the silicon carbide brick, resulting in no electrolyte Na3AlF6 in the treated silicon carbide brick, but also a small amount of AlN. Using the method provided by the invention, the recovery rate of the waste silicon nitride combined with silicon carbide bricks produced by the aluminum electrolytic cell is 99%, and the volatilized electrolyte can be recovered by condensation and can be used as the electrolyte for electrolytic aluminum.

Description

technical field [0001] The invention relates to a method for recycling waste silicon nitride combined with silicon carbide bricks from aluminum electrolysis, and belongs to the fields of resource regeneration and environmental protection. The invention relates to a silicon nitride-bonded silicon carbide product infiltrated with fluorine salt, and a method for separating and recovering the components of silicon nitride-bonded silicon carbide and fluorine salt from the solid waste after the product is used. Background technique [0002] Metal aluminum is produced by fluoride salt-alumina electrolysis. Its side walls are mainly built with silicon carbide bricks combined with silicon nitride. The composition of the brick is SiC: 70~80%, Si 3 N 4 : 20~28%. During use, the fluorine salt electrolyte penetrates into the pores of the silicon nitride bonded silicon carbide brick, and part of the silicon nitride is corroded: Si 3 N 4 (s)+4AlF 3 (l)=3SiF 4 ↑+4AlN(s). In this wa...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/10C04B35/565C25C3/08
CPCC25C3/08C01B33/103C04B35/565C04B2235/3873C04B2235/3865
Inventor 李剑峰田守信蓝振华高广震吴朝齐
Owner 上海彭浦特种耐火材料厂有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap