IP Library Granted Patent US 9,217,185
Granted Patent B2
US 9,217,185 · App. 14/352,529 · Granted Dec 22, 2015

Method of reduction processing of steel-making slag

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Quick Facts
Patent No.
US 9,217,185
App. No.
14/352,529
Granted
Dec 22, 2015
Kind
B2
Abstract

The method of reduction processing of steel-making slag, includes: a hot steel-making slag inflow process of continuously or intermittently charging, from a slag supplying container, hot steel-making slag to a molten slag layer on a molten iron contained in an electric furnace while adjusting an amount of inflow with the slag supplying container; a reducing agent supplying process of supplying a reducing agent to the molten slag layer; an electrifying and heating process of heating the molten iron and the molten slag layer through application of electric power; and a reduction process of continuing reduction processing of the hot steel-making slag in a non-oxidizing atmosphere while intermittently discharging either one or both of the molten iron or molten slag of the molten slag layer.

Claims (14)

1. A method of reduction processing of steel-making slag, including:

a hot steel-making slag inflow process of continuously or intermittently charging, from a slag supplying container, hot steel-making slag to a molten slag layer on a molten iron contained in an electric furnace while adjusting an amount of inflow with the slag supplying container;

a reducing agent supplying process of supplying a reducing agent to the molten slag layer;

an electrifying and heating process of heating the molten iron and the molten slag layer through application of electric power; and

a reduction process of continuing reduction processing of the hot steel-making slag in a non-oxidizing atmosphere while intermittently discharging the molten slag of the molten slag layer or the molten iron.

2. The method of reduction processing of steel-making slag according to claim 1 , wherein the hot steel-making slag inflow process includes:

adjusting the amount of inflow of the hot steel-making slag to the molten slag layer based on an amount of electric power supplied to the electric furnace.

3. The method of reduction processing of steel-making slag according to claim 1 , wherein the reduction process includes:

discharging, through the slag supplying container, exhaust gas emitted from the electric furnace.

4. The method of reduction processing of steel-making slag according to claim 1 , further including:

a slag modifying agent supplying process of continuously or intermittently supplying a slag modifying agent to the molten slag layer.

5. The method of reduction processing of steel-making slag according to claim 1 , further including:

a suspending process of adding, in the molten slag layer, a carbon material with an amount not less than 1.1 times and not more than 1.6 times a stoichiometric amount necessary for reduction reaction with the molten slag, thereby suspending the carbon material in the molten slag layer.

6. The method of reduction processing of steel-making slag according to claim 1 , wherein a concentration of C in the molten iron is not more than 3 mass %.

Assignments (2)
CHANGE OF NAME Recorded May 14, 2019
From: NIPPON STEEL & SUMITOMO METAL CORPORATION
To: NIPPON STEEL CORPORATION
Reel/Frame 049257/0828 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 17, 2014
From: HARADA, TOSHIYA; ARAI, TAKASHI; HIRATA, HIROSHI
To: NIPPON STEEL & SUMITOMO METAL CORPORATION
Reel/Frame 032703/0493 →