High-quality steel slag aggregate, preparation method and application thereof

By treating steel slag aggregate through a graded carbonization process, the problem of high free calcium oxide content in steel slag aggregate is solved, enabling the rapid preparation of high-quality steel slag aggregate for use in asphalt concrete.

CN119504156BActive Publication Date: 2025-11-04WUHAN UNIV OF TECH
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Patent Information

Application Number
CN202411631589.5
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2024-11-15
Publication Date
2025-11-04
Estimated Expiration
2044-11-15

AI Technical Summary

Technical Problem

Existing technologies are unable to quickly and effectively reduce the free calcium oxide content in steel slag aggregates, which limits their application in road engineering. Furthermore, conventional carbonization processes are inefficient and have long cycles.

Method used

The process employs a staged carbonization process. First, industrial waste gas is introduced under high temperature conditions to perform primary carbonization and reduction on molten steel slag. Then, secondary carbonization is carried out in a closed container. By controlling the pressure and spraying amount, the free calcium oxide content is further reduced using industrial waste gas, and high-quality steel slag aggregate is obtained through magnetic separation.

Benefits of technology

Within 24 hours, the free calcium oxide content in unaged steel slag is reduced to below 3%, meeting the standards of the transportation industry. This enables the rapid preparation of high-quality steel slag aggregate, which is suitable for the preparation of asphalt concrete.

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Abstract

The application relates to high-quality steel slag aggregate and a preparation method and application thereof, the method is a grading carbonization process, which comprises the following steps: (1) primary carbonization and reduction: taking molten steel slag in a state of 1300 DEG C-1500 DEG C as raw material, continuously introducing industrial waste gas into a hot steaming tank for carbonization in a water spraying cooling process for 8h-14h, meanwhile, making the diiron trioxide in the steel slag be reduced into iron single element and magnetite, and obtaining primary carbonized steel slag; the volume ratio of CO2 in the industrial waste gas is 20%-30%, and the volume ratio of CO is 30%-60%; (2) secondary carbonization: selecting the primary carbonized steel slag below 10mm in step (1) as aggregate, spraying the steel slag aggregate according to a preset spraying amount in a closed container, maintaining the pressure in the closed container as 0.3-0.5 Mpa, continuously introducing the same industrial waste gas into the closed container for secondary carbonization, and making the free calcium oxide content in the steel slag aggregate be lower than 3%; and magnetically selecting the high-quality steel slag aggregate after secondary carbonization. According to the method, the high-quality steel slag aggregate meeting the relevant technical requirements can be prepared within 24h, and is used for preparing asphalt concrete.
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