Enrichment of Iron from Bauxite Waste in Chemical Looping Combustion

Patent metadata

Field	Value
Publication number	US-2024360525-A1
Application number	US-202418763170-A
Country	US
Kind code	A1
Filing date	Jul 3, 2024
Priority date	Jan 26, 2022
Publication date	Oct 31, 2024
Grant date	—

Abstract

A method of recovering enriched iron fines from bauxite waste includes calcining particles of bauxite waste to form oxygen carrier particles, subjecting the oxygen carrier particles to chemical looping combustion at a temperature of about 950° C.-1,050° C. for energy production and to produce the enriched iron fines as a by-product from the oxygen carrier particles via natural attrition and collecting the enriched iron fines.

First claim

What is claimed:

1 . A method of recovering enriched iron fines from bauxite waste, comprising:
calcining particles of bauxite waste to form oxygen carrier particles; subjecting the oxygen carrier particles to chemical looping combustion at a temperature of about 950° C.-1,050° C. by (a) cyclically reducing the oxygen carrier particles in presence of a gaseous reducing agent and absence of a solid reducing agent that generates combustion ash and (b) oxidizing the oxygen carrier particles in presence of an oxidizing agent to produce energy and the enriched iron fines as a by-product from the oxygen carrier particles via natural attrition; and collecting the enriched iron fines.

2 . The method of claim 1 , wherein the calcining of the particles of bauxite waste includes heating the particles of bauxite waste to a predetermined temperature for a predetermined period of time needed to form the oxygen carrier particles.

3 . The method of claim 1 , wherein the gaseous reducing agent is selected from a group of reducing agents consisting of hydrogen, carbon monoxide, gaseous fuels and mixtures thereof.

4 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of 5-20 vol %.

5 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of 10-20 vol %.

6 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of 12-18 vol %.

7 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of about 15 vol %.

8 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of greater than 10 vol %.

9 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of greater than 12 vol %.

10 . The method of claim 1 , wherein the gaseous reducing agent is provided at a concentration of greater than 15 vol %.

11 . The method of claim 1 , further including purging the reactor bed with an inert gas between reducing and oxidizing.

12 . The method of claim 1 , wherein the oxidizing agent is air or oxygen mixed with a type of inert gas at greater than 4 vol %.

13 . The method of claim 1 , wherein the collecting of the iron enriched fines is done by using a gas-solid separation device, a baghouse, an electrostatic precipitator, a cyclone or a combination thereof.

14 . The method of claim 1 , wherein (a) the reducing includes subjecting the oxygen carrier particles in a reactor bed to heating, cooling or maintaining temperature in the presence of a reducing agent, and (b) the oxidizing includes subjecting the oxygen carrier particles in the reactor bed to heating in the presence of an oxidizing agent.

15 . The method of claim 14 , wherein the heating of the oxygen carrier particles during the reducing and the oxidizing cycles is to a temperature of between about 950° C. and about 1050° C.

16 . The method of claim 1 , further including maintaining an oxygen transport capacity of 3.5-5.0 during processing.

17 . The method of claim 1 , further including maintaining a superficial velocity of 0.2-0.4 m/s during processing.

18 . The method of claim 1 , further including using bauxite waste characterized by having about 40-45 wt % Fe 2 O 3 and about 55-60 wt % inert phases, a skeleton density of less than 4,000 kg/m 3 and a mean crush strength greater than 7.5 N.

19 . A method of recovering enriched iron fines from bauxite waste, comprising:
calcining particles of bauxite waste to form oxygen carrier particles; subjecting the oxygen carrier particles to chemical looping combustion at a temperature above 1000° C. by (a) cyclically reducing the oxygen carrier particles in presence of a gaseous reducing agent and absence of a solid reducing agent that generates combustion ash and (b) oxidizing the oxygen carrier particles in presence of an oxidizing agent to produce a spent flue gas and the enriched iron fines as a by-product from the oxygen carrier particles via natural attrition; collecting the enriched iron fines from the spent flue gas; and using the spent flue gas to generate steam for power generation.

20 . A method of recovering enriched iron fines from bauxite waste, comprising:
subjecting the oxygen carrier particles made from bauxite waste to chemical looping combustion at a temperature above 1000° C. by (a) cyclically reducing the oxygen carrier particles in presence of a gaseous reducing agent and absence of a solid reducing agent that generates combustion ash and (b) oxidizing the oxygen carrier particles in presence of an oxidizing agent to produce a spent flue gas and the enriched iron fines as a by-product from the oxygen carrier particles via natural attrition; collecting the enriched iron fines; and using the spent flue gas, following the collecting of the enriched iron fines, to generate steam for power generation.

Assignees

• Univ Kentucky Res Found

Inventors

• Huang Neng
• Omosebi Ayokunle
• Liu Kunlei
• Koumoulis Dimitrios
• Gao Xin

Classifications

• C21B2100/66

  Heat exchange · CPC title

• C21B2100/64

  Controlling the physical properties of the gas, e.g. pressure or temperature · CPC title

• C21B13/0073

  Selection or treatment of the reducing gases · CPC title

• C21B13/006 Primary

  Starting from ores containing non ferrous metallic oxides · CPC title

• C21B13/0033 Primary

  In fluidised bed furnaces or apparatus containing a dispersion of the material · CPC title