AU2020101646A4

AU2020101646A4 - A Method to Prepare High Purity Iron Oxide Red from Converter Dedusting Fine Ash by Superconducting High Gradient Magnetic Separation – Low Temperature Modification Coupling technology

Info

Publication number: AU2020101646A4
Application number: AU2020101646A
Authority: AU
Inventors: Shanci BAO; Zijie GUO; Shuaishuai HAN; Jiawei KONG; Suqin LI; Changqiao YANG
Original assignee: Unniversity Of Science And Techonolgy Beijing
Current assignee: Unniversity Of Science And Techonolgy Beijing
Priority date: 2020-08-04
Filing date: 2020-08-04
Publication date: 2020-09-10
Anticipated expiration: 2028-08-04

Abstract

of Description The present invention provides a method for preparing high-purity iron red oxide from converter dust (LT fine ash) by superconducting high gradient magnetic separation (HGMS) - low temperature modification coupling technology. Firstly, the LT fine ash is separated and purified by superconducting HGMS technology to enrich and extract ferri substances. Then, the iron oxide is roasted at low temperature to prepare high purity iron oxide red. In this way, the LT fine ash can be realized the high value recycling outside Steel Plant. The iron element can be enriched to more than 65% (the total iron content converted above 93%) by superconducting technology, the recovery of iron element is more than 95%, and the iron oxide red prepared contains a- Fe203 more than 92%. The present invention has powerful ability of ferri substances separation and extraction and ultra-low energy consumption (the energy consumption is between 1/10 and 1/4 of conventional magnetism separation methods). Because of good effect and low energy conservation, it is particularly suitable for application in enrichment, separation and extraction of ferro element from iron-containing solid fine powders, such as converter dedusting ash (LT fine ash), and high value-added resource utilization. Drawings of Description 645 * Fe 640 635 630 625 620 I * I I I a .I .I I I -a . p .p . 00 02 04 06 08 1.0 1.2 1A 16 1.8 20 22 2A 2.6 2A 3.0 Magnetic Field Intensity/T FIG.1 esoFe 655 660 U\ 9 m 645 640 0 10 20 30 40 50 60 70 60 90 100 110 Dosage of Dispersant/mg FIG.2 1/1

Description

Drawings of Description

645 * Fe

640

635

630

625

620 I * I I I a.I .I I I -a. p .p

. 00 02 04 06 08 1.0 1.2 1A 16 1.8 20 22 2A 2.6 2A 3.0

Magnetic Field Intensity/T

FIG.1

esoFe

655

660

9 m U\ 645

640

0 10 20 30 40 50 60 70 60 90 100 110

Dosage of Dispersant/mg

FIG.2

1/1

Description

A Method to Prepare High Purity Iron Oxide Red from Converter Dedusting Fine Ash by Superconducting High Gradient Magnetic Separation - Low Temperature Modification Coupling technology

Technical Field The present invention relates to resource, energy-conserving and environmental protection field, in particular to a kind of coupling technology of superconducting high gradient magnetic separation and low temperature modification is used to prepare high purity iron oxide red from converter dedusting ash.

Technical Background At present, the converter dedusting ash treatment technology mainly consists of such steel mill internal cycling processes as return to sintering, use pellet as raw material of ironmaking, briquet and return to the converter to be used as coolant. The elements such as K, Na, Zn in dedusting ash may have a negative impact on blast furnace process, the element such as P, S may have a negative impact on steel quality. Therefore, using dedusting ash in internal cycling process of steel plant is not only bad for steel production, but also is low value added.

Magnetic separation technology is a kind of technology that puts materials into magnetic field for processing. Taking the development of magnets as an opportunity, it has gone through four stages, namely, weak magnetic separation, strong magnetic separation, conventional high-gradient magnetic separation, and superconductive magnetic separation. The magnetic separation technology is firstly applied in beneficiation field. In 1792, the United Kingdom first invented a patent of magnetic separation technology used to select iron ore. In 1845, the United States invented the industrial magnetic separator. By the 1920s, various types of magnetic separators had come out one after another, the magnetic separation technology has been continuously developed and improved in the field of mineral processing. The magnetic separation technology emerged between the late 1960s and the early 1970s, it utilizes effective electricity and permanent magnets to generate a strong background magnetic field, meanwhile generates a magnetic field with higher gradient through the magnetic concentrating medium, which greatly enhances the ability to capture magnetic particles, thereby enabling the separation of materials. In 1969, the first industrial prototype of high gradient magnetic separation device was officially put into operation by the J.M. Huber Corporation. In 1972, the Pacific Scientific Inc. manufactured the first PEM84 periodic high-gradient magnetic separator. In 1975, Sala Magnetics, Inc. manufactured the first periodic high gradient magnetic filter

Description

SALA 214-14-5 to treat wastewater of steel plants.

Weak magnetic particles can only experience effective magnetic force in the high gradient and strong magnetic field, and improving magnetic field intensity generally can be achieved by means of improving the magnet structure or updating the magnet materials. Currently, the domestically developed high gradient magnetic separators are all use electric excitation, which has the disadvantages of complicated structure, high power consumption, and inconvenient maintenance, etc. With the advent of high-performance Nd-Fe-B materials, a variety of permanent magnets and intensity magnetic separators with excellent properties have appeared.

Superconductive technology is an important breakthrough in science and technology for the past few years and provides the possibility for realizing superconductive high gradient magnetic separation technology. The maximum magnetic field strength of Czech VUCHPT dielectric-type reciprocating high gradient magnetic separator applied superconducting magnets in magnetic separation technology can reach 5.0 T. The conventional magnetic separation technologies can be divided into permanent magnet technology and electromagnetic technology according to the sources of the magnetic fields: the maximum magnetic field generated by the permanent magnet is smaller, wherein, the maximum magnetic field generated by the conventional electromagnet has iron core is limited by the saturation magnetization, which is hard to exceed; the conventional electromagnet hasn't iron core requires a very large electrical excitation to obtain a large magnetic field, and uses a large amount of cooling water to prevent the winding from melting, as well as the operating cost is extremely high. However, the superconducting magnetic separation technology uses a superconducting magnet as the source of the magnetic field for magnetic separation. No matter whether the superconductive magnet uses bulk superconductors or superconducting wires, it consumes little power itself, and only requires a small amount of power to maintain low temperature to obtain a high-intensity magnetic field, does not need iron core, and there is no water cooling problem, thus it has great development prospects. The superconductive high gradient magnetic separation technology is developed from conventional high-intensity magnetic technology, which replaces conventional copper coils by superconducting coils, and has huge advantages such as environmental friendliness, energy conservation and consumption reduction. The superconductive high gradient magnetic separation technology has immense potential for development and large-scale industrial application. With the advantages of low energy consumption, high efficiency and small footprint, superconducting high-strength magnetic field is especially suitable for the extraction of micro or nano weak magnetic iron oxide which is difficult to separate from

Description

conventional magnetic field.

Invention Summary In order to solve the above problems, the present invention provides a kind of method utilizing superconductive high-gradient magnetic separation - low temperature modification coupling technology to prepare high-purity iron red oxide from converter dedusting fine ash. At first, the iron oxide are separated and extracted by superconductive high-gradient magnetic separation technology, then the iron oxide enriched is prepared high-purity ferric oxide red by low temperature roasting, and it realizes the high value-added cyclic utilization of iron-containing solid powders, such as iron-containing converter dedusting ash.

Further, the method consists of:

SI: Treatment of dedusting fine ash from converter with iron content of 30-60%;

S2: The technology of superconducting high gradient magnetic separation is used to extract iron oxide.

Further, the superconductive high-gradient magnetic separation described in the S2 specifically refers to carrying out superconductive magnetic separation under the circumstances of the magnetic field intensity is 1.2-3.OT, the volume filling rate of magnetic separation medium is 5-50%, and the powder particle size is below 100 meshes, the ore pulp density is 10-100g/ L, the ore pulp dispersant accounts for 0.1-3%, and the flow velocity of ore pulp is 100-1000mL/min, as well as the stirring velocity of pulp is 1-60r/min, and the product contains iron content more than 65%;

Further, the iron oxide extraction process described in the S2 specifically refers to modifying the iron oxide enriched by calcining for more than 30 minutes above 200°C (200-350°C ) , and thus obtain high-purity ferric oxide red, wherein the content of a-Fe203 is more than 92%;

Further, the iron oxide extraction process described in the S2 is "two-step approach" to prepare ferric oxide red. Wherein, the first step is to separate and extract iron oxide from dedusting ash by superconductive high-gradient magnetic separation technology; and the second step is to calcine and modify the iron oxide enriched, and then transform the ferric oxide into a-Fe203; the two-step approach can be implemented in different order.

Description

Further, the method is suitable for separation and extraction of iron oxide contained in all kind of iron-containing solid powders to prepare products of a-Fe203;

The beneficial effects of the present invention are as follows:

1) the ferro element can be enriched to more than 65% (it is converted into Fe203 of more than 93%), as well as the recovery rate of the ferro element reaches more than %;

2) has powerful separation and extraction ability and ultra-low energy consumption (the energy consumption is between 1/10 and 1/4 of conventional magnetism separation method), the effect is good, and the energy conservation is significant;

3) it is particularly suitable for use in the enrichment, separation, and extraction of ferro element contained in iron-containing solid powders, such as converter dedusting ash;

4) the present invention can be used to realize high value-added resource utilization of the iron-containing solid scraps, and accomplish large-scale industrial production.

Brief Description of the Drawings

FIG.1 shows under the conditions of the particle size of the ore powder is -200 mesh, the pulp density is 15 g/L, the volume filling rate of the magnetic medium is 8%, the flow velocity is 500 mL/min, and without dispersant, the iron content of the magnetic separation product obtained by the present invention changes with the strength of the magnetic field;

FIG.2 shows under the conditions of the particle size of the ore powder is -200 mesh, the pulp density is 15 g/L, the volume filling rate of the magnetic medium is 8%, the magnetic field is 1.8T, and the flow velocity is 500 mLmin, the iron content of the magnetic separation product obtained by the present invention changes with the dispersant dosage;

FIG.2 shows under the conditions of the particle size of the ore powder is -200 mesh, the pulp density is 15 g/L, the volume filling rate of the magnetic medium is 8%, the magnetic field is 1.8T, and the dispersant dosage is 30 mg/L, the iron content of the magnetic separation product obtained by the present invention changes with the flow velocity of pulp;

Description

Detailed Description of the Presently Preferred Embodiments In order to clearly illustrate the purposes, the technical schemes, and the advantages of the present invention, the present invention is explained in detail in conjunction with drawings and embodiments below. It should be appreciated that specific embodiment described herein is only used for explaining the present invention, and should not be interpreted as the limitation of the present invention. On the contrary, the present invention covers any substitutions, modifications, equivalent methods and schemes on the essences and scopes of the present invention defined in the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in the following detailed description of the present invention. As for those skilled in the art, the present invention can also be understood completely without the description of these details.

The present invention will be further described below in conjunction with the figures and specific embodiments, which should not be constructed as the limitation of the present invention. The preferred embodiments of the present invention are enumerated below:

Embodiment 1

Under the conditions that the particle size of the ore powder is -200 meshes, the pulp density is 15 g/L, the volume filling rate of the magnetic medium is 8%, the flow velocity is 500 mL/min, and without dispersant, study the iron content of magnetic separation product obtained in different magnetic field intensities.

As show in FIG.1, when the magnetic field intensity is 1.8T, the iron content of the magnetic separation product reaches the maximum of 64.5%, and with the continuous improvement of magnetic field intensity, the iron content of magnetic separation product declines instead.

Embodiment 2

Under the conditions that the particle size of the ore powder is -200 meshes, the pulp density is 15 g/L, the volume filling rate of the magnetic medium is 8%, the magnetic field intensity is 1.8T, and the flow velocity is 500 mL/min, study the iron content of magnetic separation product obtained with different dosage of sodium hexametaphosphate as the dispersant.

Description

As show in FIG.2, the studies have shown that within a certain range, as the dosage of dispersant increases, the iron content of the magnetic separation product also increases. When the concentration of the experimental dispersant is 30 mg/L, the iron content of the magnetic separation product reaches the maximum of 65.9%, and with the concentration of the dispersant continues to increase, the iron content of the magnetic separation product decreases instead.

Embodiment 3

As show in FIG.3, under the conditions that the particle size of the ore powder is -200 meshes, the pulp density is 15 g/L, the volume filling rate of the steel wool is 8%, the magnetic field intensity is 1.8T, and the dosage of dispersant added is 30 mg/L, study the iron content of the magnetic separation product under different flow velocity of pulp. The studies have shown that as the flow velocity of the pulp increases, the iron content of the magnetic separation product has been decreasing.

The present invention utilizes superconductive high-gradient magnetic separation (SHGMS) technology to extract iron oxide, particularly weak magnetic iron oxide from steelmaking converter dedusting ash has iron content between 30% and 60%. The present invention is a kind of process innovation, whereby, under the conditions that the magnetic field intensity is 1.2-3.OT, the volume filling rate of magnetic medium is 8-30%, the particle size of the ore powder is -100 meshes (without fine grinding), the pulp density is 10- 100 g/L, the ore pulp dispersant (the sodium hexametaphosphate, etc) accounts for 0. 1 -3%, the flow velocity of pulp is 100-1000mL/min and the pulp stirring velocity is 1-60 r/min, the ferro element can be enriched to more than 65%, and then be converted to Fe203 of more than 93%, thus the recovery rate of the ferro element reaches more than 95%.

The embodiments are only one of the preferred embodiments of the present invention. Any ordinary changes and replacements made by those skilled in the art within the scope of the technical schemes of the present invention should be included in the protection scope of the present invention.

Claims

1. A kind of method for preparing high-purity iron red oxide from converter dust (LT fine ash) by superconducting high gradient magnetic separation (HGMS) - low temperature modification coupling technology, characterized in that the iron oxide are separated and extracted from converter dedusting ash by superconductive high-gradient magnetic separation technology firstly, then the iron oxide enriched to be prepared high-purity ferric oxide red by roasting at low temperature, and thus realizes the high value-added cyclic utilization of iron-containing solid powders, such as iron-containing converter dedusting fine ash.

2. The method according to claim 1, is characterized in that the method consists of:

Si: Treatment of dedusting ash from converter with iron content of 30-60%;

3. The method according to claim 2, characterized in that the superconductive high-gradient magnetic separation described in the S2 specifically refers to carrying out superconductive magnetic separation under conditions which the magnetic field intensity is 1.2-3.0T, the volume filling rate of magnetic separation medium is 5-50%, and the powder particle size is below 100 meshes, the ore pulp density is 10-1OOg/ L, the ore pulp dispersant accounts for 0.1-3%, and the flow velocity of ore pulp is 100-1000mL/min, as well as the stirring velocity of pulp is 1-60r/min, and the product contains iron content more than 65%.

4. The method according to claim 2, characterized in that the iron oxide extraction process described in the S2 specifically refers to that the iron oxide extracted is roasted at 200 C -350 Cfor more than 30 minutes and modified to obtain high-purity iron oxide red, in which the content of a - Fe203 is more than 92%.

5. The method according to claim 2, characterized in that the iron oxide extraction process described in the S2 is "two-step approach" to prepare ferric oxide red. Wherein, the first step is to separate and enrich iron oxide from dedusting ash (LT ash) by superconductive high-gradient magnetic separation technology; and the second step is to roast and modify the iron oxide enriched at low temperature, and then transform the ferric oxide into a-Fe203; the two-step approach can be implemented in different order.

6. The method according to claim 1, characterized in that the method is suitable for

Claims

separation and extraction of iron oxide contained in all kind of iron-containing solid powders to prepare products of a-Fe203.