Beneficiation method for carbonate-containing iron ore

Abstract

The present invention relates to the technical field of mineral processing, and particularly relates to a beneficiation method for a carbonate-containing iron ore. The beneficiation method is characterized by comprising desliming, low-intensity magnetic separation, high-intensity magnetic separation and reverse flotation. The present invention has the beneficial effect: the problem of low iron grade and recovery rate caused by a large amount of "secondary slime" and fine-grained ore particles generated in an ore grinding process of a carbonic acid-containing iron ore is effectively solved. Low-molecular-weight sodium polyacrylate is used as a dispersing agent and can increase the electrostatic repulsion force between the particles, the surface hydrophilicity of the particles and the like, so as to promote dispersion of ore pulp; and high-molecular-weight sodium polyacrylate is used as a flocculating agent, such that the apparent diameter of the particles is increased, slime of -10 μm in the ore pulp is basically eliminated, the magnetic separation recovery rate of the fine-grained iron ore particles is increased, the influence of the fine ore particles on subsequent flotation is reduced, and efficient sorting of the carbonate-containing iron ore is achieved. According to the present invention, the problem of flotation recovery of the carbonate iron ore with the content within 10% is solved, and the beneficiation method has important significance on efficient development and utilization of carbonate-containing iron ore resources.

Description

A method for beneficiating carbonate-containing iron ore Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a beneficiation method for carbonate-containing iron ore. Background Art

[0002] As iron ore mining continues to increase in depth, the content of carbonates (primarily siderite) in iron ore continues to increase. Siderite is highly susceptible to mudification during the grinding process, producing a large amount of fine-grained slime in the -15μm or even -10μm particle size range. The light weight and large surface area of ​​fine-grained slime facilitate inter-mineral adsorption and conversion, significantly impacting flotation. Studies have shown that the adsorption of fine-grained siderite on the surfaces of hematite and quartz particles during flotation is the fundamental reason for flotation separation failure. This often leads to a series of serious problems in iron ore processing plants, including low concentrate grade, high tailings grade, decreased iron recovery, and even the inability to separate concentrate and tailings. Furthermore, the generation of fine-grained minerals significantly impacts magnetic separation performance. As ore size decreases, its specific magnetic susceptibility decreases, weakening its magnetic properties. This is particularly true for weakly magnetic minerals, which can significantly reduce iron recovery during magnetic separation, severely impacting separation performance and profitability.

[0003] Carbonate-containing iron ore is prone to mudification during the grinding process, producing large amounts of sludge and fine-grained minerals, which seriously affect magnetic separation and flotation performance. During flotation, fine-grained iron minerals are "entrained" into the tailings, resulting in iron mineral loss. Chinese invention patent application number 201510828890.X discloses a step-by-step dispersion and co-flotation separation method for fine-grained carbonate-embedded hematite ore. The fine-grained carbonate-embedded hematite ore is ground in a ball mill until the individual particles are dissociated. It is then pre-selected using weak magnetic separation and strong magnetic separation processes to obtain a mixed magnetically separated iron concentrate. This concentrate is then processed using a flotation process. A dispersant is added before the flotation reagent to reduce flocculation of the fine-grained minerals, thereby improving the quality of the flotation concentrate. This invention is of great significance for the efficient utilization of carbonate-containing hematite ore, but it does not mention the application of selective suppression and reverse flotation, which cannot further improve the concentrate recovery rate.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to provide a beneficiation method for carbonate iron ore, which overcomes the shortcomings of the existing technology. The ore slime in the ore pulp is removed by controlling the dispersion-selective desliming technology, and a selective flocculant is added to selectively flocculate the fine iron minerals in the ore pulp, thereby increasing the apparent diameter of useful minerals and reducing the influence of fine particles on magnetic separation indicators. At the same time, the reverse flotation process is used to "improve quality and reduce impurities" to improve the recovery rate and grade of the concentrate.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A method for beneficiating carbonate iron ore, characterized by comprising desludging, weak magnetic separation, high-intensity magnetic separation, and reverse flotation, wherein the specific operating steps are as follows:

[0008] (1) Desliming: Mix the ore sample to be processed with water, adjust the slurry weight concentration to 15% to 25%, stir thoroughly for 5 to 10 minutes, add low molecular weight sodium polyacrylate to the slurry at a concentration of 3 to 8 mg / L and stir for 5 to 30 minutes, deslim the slurry, and the overflow slurry has a particle size of less than 15 μm. The overflow slurry is directly discharged as tailings;

[0009] (2) weak magnetic separation, the sand settling product in step (1) is subjected to weak magnetic separation, the magnetic field strength of the weak magnetic separation is 80mT to 250mT, and the pulp concentration is controlled at 20% to 35%;

[0010] (3) Strong magnetic separation: adjust the concentration of weak magnetic tailings pulp to 35% to 45%, add high molecular weight sodium polyacrylate to the weak magnetic tailings pulp at a concentration of 3 to 5 mg / L and stir for 5 to 30 minutes, then feed it into the strong magnetic separation operation. The magnetic field strength of the strong magnetic separation is 800 mT to 1200 mT, and the pulp concentration is controlled at 15% to 25%. The strong magnetic tailings are directly discarded, and the strong magnetic concentrate is combined with the demagnetized weak magnetic concentrate to obtain a mixed magnetic concentrate;

[0011] (4) Reverse flotation: the mixed magnetic concentrate slurry obtained in step (3) is adjusted to a concentration of 30% to 45%, stirred and mixed, and the flotation operation is completed according to the reverse flotation process. The obtained flotation concentrate has a grade of more than 65% and an operation recovery rate of more than 70%.

[0012] Furthermore, the ore sample to be processed in step (1) is an iron ore with an iron carbonate content not higher than 10%, and the ore is ground to a particle size of -74 μm with a content greater than 90%.

[0013] Furthermore, the molecular weight of the low molecular weight sodium polyacrylate in step (1) is 1000 to 5000.

[0014] Furthermore, the desludging operation in step (1) adopts a desludging bucket, a hydrocyclone or a sedimentation bottle, which is a one-stage desludging operation or a multi-stage desludging operation.

[0015] Furthermore, the molecular weight of the high molecular weight sodium polyacrylate in step (3) is 2 million to 3 million, and the stirring speed is 500-3000 rpm.

[0016] Furthermore, the weak magnetic operation uses any one of a permanent magnetic drum magnetic separator, a permanent magnetic rotating magnetic field magnetic separator, an electromagnetic drum magnetic separator or a magnetic separation column.

[0017] Furthermore, the strong magnetic operation uses any one of a Slon vertical ring pulsating high gradient magnetic separator, an electromagnetic induction roller strong magnetic separator, and a Jones type strong magnetic field magnetic separator.

[0018] Furthermore, the flotation machine selected for the flotation operation is any one of a self-aspirating mechanical stirring flotation machine, an aerated mechanical stirring flotation machine or a flotation column.

[0019] By adding low-molecular-weight sodium polyacrylate, the present invention increases the electrostatic repulsion and hydrophilicity between particles, promotes the dispersion of the slurry, reduces agglomeration and adhesion between particles, and creates conditions for desliming in the next step. Desliming the fully dispersed slurry removes harmful slimes, facilitating the next step of sorting.

[0020] Weak magnetic separation can be used to separate strongly magnetic minerals, thus preventing "inclusions" between magnetically aggregated minerals and reducing the effectiveness of subsequent selective flocculation. Selective flocculation of weakly magnetic tailings selectively flocculates fine iron ore in the slurry, increasing its apparent diameter and eliminating -10μm slime. This improves the magnetic separation recovery rate of fine iron ore particles while reducing their impact on subsequent flotation. Using sodium polyacrylates of varying molecular weights, both of which have a selective inhibitory effect on iron ore, reverse flotation can effectively improve the recovery rate and grade of concentrates.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) This invention effectively addresses the dual issues of low iron grade and recovery, resulting from the large amounts of "secondary slime" and fine particles generated during the grinding process of carbonate-containing iron ore. Low-molecular-weight sodium polyacrylate, used as a dispersant, enhances the electrostatic repulsion between particles and the hydrophilicity of the particle surface, promoting slurry dispersion. High-molecular-weight sodium polyacrylate, used as a flocculant, increases the apparent particle diameter, essentially eliminating slime below -10μm in the slurry. This improves the magnetic separation recovery of fine iron ore particles and reduces the impact of fine particles on subsequent flotation, achieving efficient separation of carbonate-containing iron ore.

[0023] 2) Compared with existing flotation methods, the present invention solves the flotation recovery problem of carbonate iron ore with a content of less than 10%, and improves the recovery rate and grade of iron ore through dispersion-desliming-flocculation technology, which is of great significance to the efficient development and utilization of carbonate iron ore resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a flow chart of a separation process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the present invention. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying any creative work.

[0027] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention.

[0028] Figure 1 is a schematic diagram of an embodiment of a beneficiation method for carbonate iron ore according to the present invention. The carbonate iron ore used in this embodiment was sourced from Anshan, Liaoning Province. The dispersant is low-molecular-weight sodium polyacrylate with a molecular weight of 1,000 to 5,000, and the flocculant is sodium polyacrylate with a molecular weight of 2 to 3 million. Desludging operations utilize a desludging bucket, hydrocyclone, or settling bottle. A permanent magnetic drum separator is used for weak magnetic separation, while a Slon vertical ring high-gradient magnetic separator is used for strong magnetic separation. Flotation reagents include starch as a depressant, NaOH as a pH adjuster, CaCl2 as an activator, and sodium oleate as a collector, all of analytical grade. A 500mL XFD single-cell flotation cell performs three-sweep reverse flotation, one coarse, one fine, and one fine.

[0029] Example 1

[0030] The carbonate iron ore selected in this implementation case has a particle size of -74μm and a content of 90% after crushing and grinding, and a total iron grade of 34.5%. The main minerals are magnetite, hematite, siderite and quartz, of which the siderite content is 5%. The specific operation steps are as follows:

[0031] (1) Desliming: Take the above-mentioned ore sample to be processed and mix it with water, adjust the slurry weight concentration to 15%, stir at 1900 rpm, stir thoroughly for 5 minutes, add low molecular weight sodium polyacrylate to the slurry at a concentration of 4 mg / L and stir for 5 minutes; feed the slurry into a hydrocyclone for a first-stage desliming treatment, and directly discharge the overflow sludge as tailings, and feed the sedimentation product into the next operation;

[0032] (2) weak magnetic separation, the sand settling product obtained in step (1) is subjected to weak magnetic separation, the magnetic field strength of the weak magnetic separation is 100 mT, and the pulp concentration is controlled at 30%;

[0033] (3) Strong magnetic separation: adjust the weak magnetic tailings slurry concentration to 35%, add high molecular weight sodium polyacrylate to the weak magnetic tailings slurry at a concentration of 4 mg / L and stir for 5 minutes before feeding into the strong magnetic separation operation. The magnetic field strength of the strong magnetic separation is 1000 mT, and the slurry concentration is controlled at 20%. The strong magnetic tailings are directly discarded, and the strong magnetic concentrate and the demagnetized weak magnetic concentrate are combined into the flotation feed;

[0034] (4) Reverse flotation: The ore pulp concentration of the flotation feed obtained in step (3) is adjusted to 32%, stirred and mixed, and then subjected to a three-sweep reverse flotation closed-circuit operation of one coarse and one fine in an XFD single-tank flotation machine.

[0035] The final flotation concentrate grade is 66.32%, and the flotation recovery rate is 82.23%.

[0036] Example 2

[0037] The carbonate iron ore selected in this implementation case has a particle size of -44μm and a content of 80% after crushing and grinding, and a total iron grade of 33.6%. The main minerals are magnetite, hematite, siderite and quartz, of which the siderite content is 6.5%. The specific operation steps are as follows:

[0038] (1) Desliming: Take the above-mentioned ore sample to be processed and mix it with water, adjust the slurry weight concentration to 15%, stir at a speed of 1900 rpm, stir thoroughly for 6 minutes, add low molecular weight sodium polyacrylate to the slurry at a concentration of 5 mg / L and stir for 5 minutes; the resulting slurry is fed into a sedimentation bottle for a first-stage desliming treatment, and the overflow slurry is directly discharged as tailings, and the sedimentation product is fed to the next operation;

[0039] (2) weak magnetic separation, the sand settling product obtained in step (1) is subjected to weak magnetic separation, the magnetic field strength of the weak magnetic separation is 120mT, and the pulp concentration is controlled at 30%;

[0040] (3) Strong magnetic separation: adjust the weak magnetic tailings slurry concentration to 40%, add high molecular weight sodium polyacrylate to the weak magnetic tailings slurry at a concentration of 4 mg / L and stir for 5 minutes before feeding into the strong magnetic separation operation. The magnetic field strength of the strong magnetic separation is 900 mT, and the slurry concentration is controlled at 18%. The strong magnetic tailings are directly discarded, and the strong magnetic concentrate and the demagnetized weak magnetic concentrate are combined into the flotation feed;

[0041] (4) Reverse flotation: The ore pulp concentration of the flotation feed obtained in step (3) is adjusted to 32%, stirred and mixed, and then subjected to a three-sweep reverse flotation closed-circuit operation of one coarse and one fine in an XFD single-tank flotation machine.

[0042] The final flotation concentrate grade is 65.52%, and the flotation recovery rate is 80.15%.

[0043] Example 3

[0044] The carbonate iron ore selected in this implementation case has a particle size of -44μm and a content of 90% after crushing and grinding, and a total iron grade of 32.5%. The main minerals are magnetite, hematite, siderite and quartz, of which the siderite content is 5.5%. The specific operation steps are as follows:

[0045] (1) Desliming: Take the above-mentioned ore sample to be processed and mix it with water, adjust the slurry weight concentration to 15%, stir at 1900 rpm, stir thoroughly for 5 minutes, add low molecular weight sodium polyacrylate to the slurry at a concentration of 4 mg / L and stir for 5 minutes; the resulting slurry is fed into a desliming hopper for a first-stage desliming treatment, and the overflow slurry is directly discharged as tailings, and the sand settling product is fed to the next operation;

[0046] (2) weak magnetic separation, the sand settling product obtained in step (1) is subjected to weak magnetic separation, the magnetic field strength of the weak magnetic separation is 110mT, and the pulp concentration is controlled at 30%;

[0047] (3) Strong magnetic separation: adjust the weak magnetic tailings slurry concentration to 35%, add high molecular weight sodium polyacrylate to the weak magnetic tailings slurry at a concentration of 4 mg / L and stir for 5 minutes before feeding into the strong magnetic separation operation. The magnetic field strength of the strong magnetic separation is 1000 mT, and the slurry concentration is controlled at 18%. The strong magnetic tailings are directly discarded, and the strong magnetic concentrate and the demagnetized weak magnetic concentrate are combined into the flotation feed;

[0048] (4) Reverse flotation: The ore pulp concentration of the flotation feed obtained in step (3) is adjusted to 32%, stirred and mixed, and then subjected to a three-sweep reverse flotation closed-circuit operation of one coarse and one fine in an XFD single-tank flotation machine.

[0049] The final flotation concentrate grade is 65.32%, and the flotation recovery rate is 81.10%.

[0050] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for beneficiating carbonate iron ore, characterized in that: Including desludging, weak magnetic separation, strong magnetic separation, reverse flotation, the specific operation steps are as follows: (1) Desliming: Mix the ore sample to be processed with water, adjust the weight concentration of the slurry to 15% to 25%, stir thoroughly for 5 to 10 minutes, add low molecular weight sodium polyacrylate to the slurry at a concentration of 3 to 8 mg / L and stir for 5 to 30 minutes, deslim the slurry, and the particle size of the overflow slurry is less than 15 μm, and the overflow slurry is directly discharged as tailings; (2) weak magnetic separation, the sand settling product in step (1) is subjected to weak magnetic separation, the magnetic field strength of the weak magnetic separation is 80mT to 250mT, and the pulp concentration is controlled at 20% to 35%; (3) Strong magnetic separation: adjust the concentration of weak magnetic tailings slurry to 35% to 45%, add high molecular weight sodium polyacrylate to the weak magnetic tailings slurry at a concentration of 3 to 5 mg / L and stir for 5 to 30 minutes, then feed it into strong magnetic separation operation, the magnetic field strength of strong magnetic separation is 800mT to 1200mT, the slurry concentration is controlled at 15% to 25%, the strong magnetic tailings are directly discarded, and the strong magnetic concentrate is combined with the demagnetized weak magnetic concentrate to obtain a mixed magnetic concentrate; (4) reverse flotation, adjusting the concentration of the mixed magnetic concentrate slurry obtained in step (3) to 30% to 45%, stirring and mixing, and completing the flotation operation according to the reverse flotation process, the obtained flotation concentrate has a grade of more than 65% and an operation recovery rate of more than 70%.

2. The method for beneficiating carbonate-containing iron ore according to claim 1, characterized in that: The ore sample to be processed in step (1) is an iron ore with an iron carbonate content not higher than 10%, and the ore is ground to a particle size of -74 μm with a content greater than 90%.

3. The method for beneficiating carbonate-containing iron ore according to claim 1, characterized in that: The molecular weight of the low molecular weight sodium polyacrylate in step (1) is 1000 to 5000.

4. The method for beneficiating carbonate-containing iron ore according to claim 1, characterized in that: The desludging operation in step (1) adopts a desludging bucket, a hydrocyclone or a sedimentation bottle, which is a one-stage desludging operation or a multi-stage desludging operation.

5. The method for beneficiating carbonate-containing iron ore according to claim 1, characterized in that: The molecular weight of the high molecular weight sodium polyacrylate in step (3) is 2 million to 3 million, and the stirring speed is 500-3000 rpm.

6. The method for beneficiating carbonate iron ore according to claim 1, characterized in that: The weak magnetic operation uses any one of a permanent magnetic drum magnetic separator, a permanent magnetic rotating magnetic field magnetic separator, an electromagnetic drum magnetic separator or a magnetic separation column.

7. The method for beneficiating carbonate iron ore according to claim 1, characterized in that: The strong magnetic operation uses any one of a Slon vertical ring pulsating high gradient magnetic separator, an electromagnetic induction roller strong magnetic separator, and a Jones type strong magnetic field magnetic separator.

8. The method for beneficiating carbonate iron ore according to claim 1, characterized in that: The flotation machine selected for the flotation operation is any one of a self-aspirating mechanical stirring flotation machine, an aerated mechanical stirring flotation machine or a flotation column.

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