Process for the combined manufacture of steel and cement clinker

Patent metadata

Field	Value
Publication number	US-2024318271-A1
Application number	US-202218579112-A
Country	US
Kind code	A1
Filing date	Jul 15, 2022
Priority date	Jul 16, 2021
Publication date	Sep 26, 2024
Grant date	—

Abstract

A process is disclosed for the combined manufacture of steel and cement clinker. Steel scrap is loaded in an electric arc furnace for forming molten steel. Cement paste derived from construction and demolition waste is loaded in the electric arc furnace to act as a flux for the steel to assist in the removal of impurities from the molten steel and forming an electric are furnace slag. The heat of the molten steel promotes clinkering of the electric are furnace slag to form clinkered electric arc furnace slag. The clinkered electric arc furnace slag is removed from the electric arc furnace.

First claim

1 . A process for the combined manufacture of steel and cement clinker, the process including the steps:
providing an electric arc furnace; providing steel scrap; providing cement paste derived from construction and demolition waste; loading the steel scrap in the electric arc furnace for forming molten steel; loading the cement paste in the electric arc furnace to act as a flux for the steel to assist in the removal of impurities from the molten steel and forming an electric arc furnace slag, wherein the heat of the molten steel promotes clinkering of the electric arc furnace slag to form clinkered electric arc furnace slag; and removing the clinkered electric arc furnace slag from the electric arc furnace.

2 . The process according to claim 1 wherein the maximum operating temperature experienced by the clinkered electric arc furnace slag in the electric arc furnace is at least 1500° C.

3 . The process according to claim 1 wherein the clinkered electric arc furnace slag, on removal from the electric arc furnace, is cooled from the operating temperature of the electric arc furnace and the cooling rate of the clinkered electric arc furnace slag is such that the temperature of the clinkered electric arc furnace slag cools from the operating temperature of the electric arc furnace to 950° C. or below in a time of 20 minutes or less.

4 . The process according to claim 1 wherein the cement paste added to the electric arc furnace is pelletised before being added to the electric arc furnace.

5 . The process according to claim 1 wherein the cement paste is combined with one or more additional materials to assist with fluxing of the steel.

6 . The process according to claim 5 wherein the additional material is or includes CaO.

7 . The process according to claim 5 wherein the ratio of cement paste to additional material is in the range defined by 75 wt % cement paste: 25 wt % additional material at one limit to 99 wt % cement paste: 1 wt % additional material at the other limit.

8 . The process according to any one of claim 1 wherein the clinkered electric arc furnace slag is Portland cement clinker.

9 . The process according to claim 1 wherein the clinkered electric arc furnace slag is a hydraulic material consisting of at least two-thirds by mass of calcium silicates, the ratio of CaO to SiO2 is not less than 2.0 and the magnesium oxide content does not exceed 5.0% by mass.

10 . The process according to claim 9 wherein the calcium silicates are Alite, Belite, or a combination of Alite and Belite.

11 . Cement clinker obtained as a product of a process of combined manufacture of steel and cement clinker, the process including the steps:
providing an electric arc furnace; providing steel scrap; providing cement paste derived from construction and demolition waste; loading the steel scrap in an electric arc furnace for forming molten steel; loading the cement paste in the electric arc furnace to act as a flux for the steel to assist in the removal of impurities from the molten steel and forming an electric arc furnace slag, wherein the heat of the molten steel promotes clinkering of the electric arc furnace slag to form clinkered electric arc furnace slag; and removing the clinkered electric arc furnace slag from the electric arc furnace.

12 . Cement obtained by or obtainable by grinding the cement clinker of claim 11 and adding gypsum.

13 . Cement according to claim 12 which is CEM I cement.

Assignees

• Cambridge Entpr Ltd

Inventors

• Dunant Cyrille
• Allwood Julian M
• Horton Philippa

Classifications

• C21C2200/00

  Recycling of waste material · CPC title

• C21C5/527

  Charging of the electric furnace · CPC title

• C04B18/067

  Slags · CPC title

• C04B7/19

  Portland cements · CPC title

• Y02P40/18

  Carbon capture and storage [CCS] · CPC title