Method of recovering Fe from steel-making slag

Patent metadata

Field	Value
Publication number	US-9650688-B2
Application number	US-201414228815-A
Country	US
Kind code	B2
Filing date	Mar 28, 2014
Priority date	Jul 4, 2013
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A method of recovering Fe from steel-making slag is disclosed. The method includes the steps of melting steel-making slag having a higher Fe content than iron-making slag by heating the steel-making slag to a first temperature; cooling the molten slag to a second temperature that is lower than the first temperature and then maintaining the same at the second temperature for a predetermined time to thus precipitate Fe in the molten slag, thereby forming and growing an Fe-rich phase; rapidly cooling the slag to room temperature; and crushing the solidified slag and magnetically separating a magnetically-susceptible portion from a magnetically-unsusceptible portion.

First claim

The invention claimed is:

1. A method of recovering Fe from a steel-making slag, the method comprising the following steps of:
melting the steel-making slag having a higher Fe content than an iron-making slag by heating the steel-making slag to a first temperature ranging from 1450° C. to 1600° C. to make a molten slag;
cooling the molten slag to a second temperature ranging from 1150° C. to 1250° C. and then maintaining the second temperature for 10 minutes or longer, thereby forming and growing an Fe-rich spinel phase and an Fe-poor amorphous phase;
rapidly cooling the molten slag to room temperature to form a solidified slag after maintaining the second temperature for 10 minutes or longer; and
crushing the solidified slag and separating a magnetically-susceptible portion from a magnetically-unsusceptible portion by applying a magnetic separation to the solidified slag,
wherein, in maintaining the second temperature for 10 minutes or longer, the Fe-rich spinel phase is formed and grown, and the Fe-poor amorphous phase is formed from an Fe-depleted liquid slag, and
wherein an Fe-rich slag from the Fe-rich spinel phase and an Fe-poor amorphous slag from the Fe-poor amorphous phase are separated from each other by the magnetic separation.

2. The method according to claim 1 , wherein the steel-making slag is electric furnace slag or converter slag.

Assignees

• Industry-Academic Cooperation Foundation Yonsei Univ

Inventors

• Sohn Il
• Jung Sungsuk

Classifications

• C21B3/08 Primary

  Cooling slag · CPC title

• C21B2200/00

  Recycling of non-gaseous waste material · CPC title

• C21C5/54

  Processes yielding slags of special composition · CPC title

• C21C5/00

  Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel {or stainless steel} · CPC title

• C21C5/36

  Processes yielding slags of special composition · CPC title