Multi-stage suspension magnetizing roasting-magnetic separation system device and method for refractory iron ore

Patent metadata

Field	Value
Publication number	US-10543491-B2
Application number	US-201815991690-A
Country	US
Kind code	B2
Filing date	May 29, 2018
Priority date	Mar 31, 2017
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

The invention discloses a multi-stage suspension magnetizing roasting-magnetic separation system and method for refractory iron ore, which belongs to the field of mineral processing technology. This system comprises multistage suspension preheater, multistage suspension oxidizer, multistage suspension redactor, on-line grade analyzer, ore-like splitter, magnetic separator, dust remover, roots blower and other components and connection modes. The refractory iron ore treated by the present method can be produced to homogeneous magnetite or maghemite accurately, and through magnetic separation, on-line grade analyzer detection and ore-like splitter, the concentrate powder which reach the set grade can be obtained, and the unqualified ore powder enters the next stage of oxidation-reduction-magnetic separation-split treatment. Through the present system and method, products with different roasting quality can be obtained, and can avoid the phenomenon of over burning or under burning occurring in the past process and equipment.

First claim

The invention claimed is:

1. A multi-stage suspension magnetizing roasting-magnetic separation system for processing a refractory iron ore, comprising: a feed bin, a suspension preheater, a gas burner, a first-stage suspension oxidizer, a first-stage suspension reductor, a first-stage electromagnetic dry magnetic separator, a first-stage X-ray fluorescence online grade analyzer, a first-stage splitter, a second-stage suspension oxidizer, a second-stage suspension reductor, a first-stage tailings collector, a first-stage concentrate collector, a second-stage tailings collector, a second-stage concentrate collector, a second-stage middling ore collector, a cyclone separator, a dust remover, a dust collector, a roots blower, a second-stage electromagnetic dry magnetic separator, a second-stage X-ray fluorescence online grade analyzer, and a second-stage splitter, wherein a feed inlet of the suspension preheater is connected to a discharge outlet of the feed bin, and a discharge outlet of the suspension preheater is connected to a feed inlet of the first-stage suspension oxidizer,
wherein a top discharge outlet of the first-stage suspension oxidizer is connected to a feed inlet of the cyclone separator, a bottom discharge outlet of the first-stage suspension oxidizer is connected to an inlet of the first-stage suspension reductor, a bottom discharge outlet of the first-stage reductor is connected to a feed inlet of the first-stage electromagnetic dry magnetic separator, and the first-stage X-ray fluorescence online grade analyzer is disposed between an outlet of the first-stage electromagnetic dry magnetic separator, and an inlet of the first-stage splitter,
wherein the first-stage splitter has a high-grade discharge outlet connected to the first-stage concentrate collector and a low-grade discharge outlet connected to an inlet of the second-stage suspension oxidizer, and a tailings outlet of the first-stage electromagnetic dry magnetic separator is connected to the first-stage tailings collector,
wherein an outlet of the second-stage suspension oxidizer is connected to a feed inlet of the second stage-suspension reductor, and a bottom discharge outlet of the second-stage suspension reductor is connected to a feed inlet of the second-stage electromagnetic dry magnetic separator,
wherein the second-stage X-ray fluorescence online grade analyzer is disposed between a concentrate outlet of the second-stage electromagnetic dry magnetic separator and an inlet of the second-stage splitter,
wherein the second stage splitter has a high-grade concentrate outlet connected to the second-stage concentrate collector and a low-grade concentrate outlet connected to the second-stage middling ore collector, and a tailings outlet of the second-stage electromagnetic dry magnetic separator is connected to the second-stage tailings collector, and
wherein a dust gas outlet at a top of the cyclone separator is connected to a dust gas inlet of the dust remover, an air outlet at a top of the dust remover is connected to the roots blower, and a dust outlet of the dust remover is connected to the dust collector.

2. The multi-stage suspension magnetizing roasting-magnetic separation system according to claim 1 , wherein the discharge outlet of the suspension preheater is disposed at a top of the suspension preheater,
wherein the suspension preheater further comprises a feed inlet disposed at a sidewall, and a gas inlet at a bottom of the suspension preheater, and wherein the gas inlet of the suspension preheater is connected to the gas burner.

3. The multi-stage suspension magnetizing roasting-magnetic separation system according to claim 1 , wherein the first-stage suspension oxidizer, the first-stage suspension reductor, the second-stage suspension oxidizer, and the second-stage suspension reductor each has a plurality of electric heating devices affixed to an external surface thereof.

4. The multi-stage suspension magnetizing roasting-magnetic separation system according to claim 1 , wherein the first-stage suspension reductor and the second-stage suspension reductor each has a reducing gas spray inlet and a protective gas spray inlet.

5. A method for processing a refractory iron ore in the system of claim 1 , comprising:
(1) feeding a material that is a powder of the refractory iron ore through the feed bin into the suspension preheater, feeding a combustion flue gas from the gas burner to a gas inlet of the suspension preheater, controlling a temperature of the material in the suspension preheater at 600-1300° C. in a suspension state;
(2) starting the roots blower to create a negative pressure to move a preheated material in the suspension preheater into the first-stage suspension oxidizer, controlling a temperature of a material at 800-1200° C. and for a residence time of 10-60 min in the first-stage suspension oxidizer while maintaining an oxidizing atmosphere in the first-stage suspension oxidizer;
feeding an oxidized material to the first-stage suspension reductor, feeding a reducing gas into the first-stage suspension reductor, controlling a temperature of a material at 450-700° C. and for a residence time of 5-25 min in the first-stage suspension reductor, wherein the reducing gas comprises nitrogen and 10-40 vol % of carbon monoxide and hydrogen;
(3) separating a reduced material from the first stage suspension reductor in the first-stage electromagnetic dry magnetic separator at a magnetic field intensity of 1000-5000 Oe to obtain a first concentrate and a first tailings, determining a grade of the first concentrate using the first-stage X-ray fluorescence online grade analyzer, when the first concentrate has a grade higher than a preset value, feeding the first concentrate to the first-stage concentrate collector as a finished product, and when the first concentrate has a grade lower than the preset value, feeding the first concentrate as a low-grade concentrate to the second-stage suspension oxidizer, and discharging the first tailings of the first-stage electromagnetic dry magnetic separator into the first-stage tailings collector;
(4) controlling a temperature of the low-grade concentrate at 700-1100° C. and for a residence time of 10-30 min in the second-stage suspension oxidizer to produce an oxidized low-grade concentrate; feeding the reducing gas into the second-stage suspension redactor; reducing the oxidized low-grade concentrate in the second-stage suspension reductor at a temperature of 450-700° C. for 5-15 min in the reducing gas;
(5) feeding a reduced low-grade concentrate into the second-stage electromagnetic dry magnetic separator to carry out a second-stage electromagnetic separation at a magnetic field intensity of 1000-5000 Oe to obtain a second concentrate and a second tailings; determining a grade of the second concentrate using the second-stage X-ray fluorescence online grade analyzer, when the second concentrate has a grade higher than the preset value, feeding the second concentrate into the second-stage concentrate collector, when the second concentrate has a grade lower than the preset value, feeding the second concentrate into the second-stage middling ore collector; discharging the second tailings into the second-stage tailings collector; and
(6) feeding a dust gas discharged from the second-stage suspension oxidizer and the cyclone separator into the dust remover; discharging a gas separated from the dust remover is into the atmosphere through an air outlet of the roots blower, and discharging a solid ash from the dust remover into the dust collector through a bottom outlet of the dust remover.

6. The method according to claim 5 , wherein a total amount of the reducing gas fed into the first-stage suspension reductor and the second-stage suspension reductor satisfies a molar ratio of CO and

Assignees

• Univ Northeastern

Inventors

• Han Yuexin
• Li Yanjun
• Yuan Shuai
• Gao Peng
• Sun Yongsheng
• Li Wenbo

Classifications

• F27B1/005

  wherein no smelting of the charge occurs, e.g. calcining or sintering furnaces · CPC title

• F27B15/02

  Details, accessories or equipment specially adapted for furnaces of these types · CPC title

• B03C2201/20

  Magnetic separation of bulk or dry particles in mixtures · CPC title

• C22B1/00

  Preliminary treatment of ores or scrap · CPC title

• C21B13/146

  Multi-step reduction without melting · CPC title