Mineral separation system and mineral separation process for ultra-lean magnetite

Abstract

The invention discloses a mineral separation system for ultra-lean magnetite. The mineral separation system comprises a coarse crusher, an intermediate crusher, a fine crusher, a dry magnetic separator and wet grinding separation equipment which are connected in sequence, the fine crusher is connected with the dry type magnetic separator through a multi-stage classifier, and the dry type magnetic separator is a pipeline dry separator, a suspension type magnetic separator or a boiling dry type magnetic separator. The invention further discloses a beneficiation process of the beneficiation system, which comprises the following steps of: obtaining fine-fraction ore by using the crushing equipment, separating the fine-fraction ore into ore powder with three grades of more than 3mm, 0.5-3mm and less than 0.5 mm by using the multi-stage classifier, performing magnetic separation on the ore powder with the granularity of more than 3mm by using the suspension type magnetic separator, performing magnetic separation on the ore powder with the granularity of 0.5-3mm by using the pipeline dry separator, and performing magnetic separation on the ore powder with the granularity of less than 0.5 mm by using the boiling dry type magnetic separator. Equipment abrasion is reduced, and the occupied area of equipment is reduced. The pipeline dry separator is flexible in arrangement, the occupied space is saved, and the dust removal problem does not need to be considered in the separation process.

Description

Technical Field

[0001] The present invention belongs to the technical field of mineral processing, and in particular relates to a mineral processing system and a mineral processing process for ultra-lean magnetite. Background Art

[0002] Currently, the technology used to process ultra-lean magnetite mostly relies on dry separation with magnetic pulleys, followed by large-block jigging followed by crushing and wet grinding. This results in low tailings rejection rates, significant metal loss, high beneficiation costs, and low economic returns, leaving many beneficiation companies in a loss-making state. Because ultra-lean magnetite has a fine iron ore distribution, conventional crushing products are too coarse, resulting in a very low dry tailings rejection rate (less than 5% for a crushed particle size of -12 μm), and poor pre-grinding dry separation. Conventional grinding processes for ultra-lean magnetite utilize three-stage or two-stage closed-circuit crushing, ball mill grinding, and wet magnetic separation. This conventional process, after coarse, medium, and fine crushing, enters the grinding stage when the ore particle size reaches below 15 mm. This results in heavy mill loads, high energy consumption, and high final concentrate costs.

[0003] Conventional wet magnetic separation processes require an average of 4-5 tons of water to process 1 ton of ultra-lean magnetite ore. The water consumption of the concentrator is extremely high, and a tailings pond must be built to store wet tailings sand. The construction of a tailings pond with wet tailings requires high investment, great safety risks, and high operating and maintenance costs.

[0004] To address this issue, our company applied for an invention patent in 2015, with the authorization publication number CN105413842B. The invention is titled "Process and System for the Beneficiation of Ultra-Lean Magnetite." This invention provides a process and system for the beneficiation of ultra-lean magnetite, comprising the following steps: sequentially crushing the magnetite ore through coarse, medium, and fine crushing to obtain fine-grained ore; subjecting the fine-grained ore to dry magnetic separation, discarding the tailings, and obtaining a dry concentrate; and subjecting the dry concentrate to wet grinding. This invention addresses technical issues such as high energy consumption and cost associated with grinding and magnetic separation, high water consumption, and the need for tailings ponds.

[0005] However, subsequent practice revealed that the drum magnetic separator of this invention had low separation accuracy, often leaving some useful minerals in the discarded waste rock, reducing the recovery rate. Furthermore, the drum magnetic separator had low production capacity, and when used in large mines, multiple drum magnetic separators were required, requiring a larger floor space and increasing operating costs.

[0006] In actual use, the boiling effect of 0.5-3mm mineral powder decreases due to the increase in mineral powder weight, which in turn leads to a decrease in separation index. Therefore, it is difficult for 0.5-3mm mineral powder to achieve a good boiling state under the action of airflow, resulting in poor magnetic separation effect.

[0007] Therefore, it is necessary to improve the existing technology to reduce wear on equipment, improve separation accuracy and increase recovery rate. Summary of the Invention

[0008] The present invention solves at least one of the above-mentioned technical problems. One of the purposes of the present invention is to provide a beneficiation system for ultra-lean magnetite. The system uses a suspension magnetic separator, a pipeline dry separator, a boiling dry magnetic separator and other equipment to reduce the wear of the equipment on the mineral, improve the separation accuracy and increase the recovery rate.

[0009] A beneficiation system for ultra-lean magnetite, comprising a coarse crusher, a medium crusher, a fine crusher, a dry magnetic separator and a wet grinding and separation device connected in sequence;

[0010] The fine crusher is connected to the dry magnetic separator through a multi-stage classifier, and the dry magnetic separator includes a pipeline dry separator, a suspension magnetic separator, and a boiling dry magnetic separator; the disintegration classifier is connected to the pipeline dry separator, the suspension magnetic separator, and the boiling dry magnetic separator respectively.

[0011] Preferably, the pipeline dry sorting machine includes a rotating air duct and a motor. The pipeline dry sorting machine includes a rotating air duct and a motor. The motor is connected to the rotating air duct. A magnetic plate is provided on the outside of the rotating air duct. The magnetic plate is a tubular structure with an opening. A conveyor is provided inside the rotating air duct. The upper end of the conveyor is open. The opening position of the conveyor is opposite to the opening position of the magnetic plate. The conveyor is provided with a discharge port. A discharge scraper is provided on the conveyor. The discharge scraper is adapted to the opening at the upper end of the conveyor.

[0012] The rotating air duct of the pipeline dry separator rotates driven by the motor, and the discharge scraper is at a certain angle to the inner wall of the rotating air duct. This setting makes it easy to scrape the material away.

[0013] The conveyor is preferably a screw conveyor with an internal screw rod.

[0014] Based on the opening position of the magnetic plate, the dry pipe separator is divided into a sorting area and a discharge area. The area enclosed by the arc covered by the magnetic plate and the center of the rotating air duct is the sorting area, and the area enclosed by the arc of the magnetic plate opening (the position not covered by the magnetic plate) and the center of the rotating air duct is the discharge area.

[0015] The discharge scraper is fixed on the outer shell of the screw conveyor. The function of the discharge scraper is to scrape off the material on the inner wall of the rotating air duct. The discharge scraper is fixed in the discharge area and does not rotate with the rotating air duct.

[0016] When the dry pipe separator is operating, material (0.5mm-3mm fines) enters the rotating duct. Due to the magnetic poles of the outer magnetic plate, the magnetite is attracted to the inner wall of the rotating duct. The rotating duct rotates, carrying the attracted magnetite from the separation area to the discharge area. Once in the discharge area, the magnetite is removed by the discharge scraper and falls into the opening of the conveyor. The conveyor then transports the magnetite to the discharge port, which is connected to the fine crusher.

[0017] The pipeline dry separator needs to be used in conjunction with an air duct or fan.

[0018] Preferably, the suspension magnetic separator is of model LJC-15000, and the boiling dry separator is of model DMS-B180.

[0019] Preferably, the multi-stage classifier is a scattering classifier.

[0020] Preferably, an air duct is provided between the multi-stage classifier and the pipeline dry separator.

[0021] The air duct is a pipe used to transport mineral powder. The pipe dry separator can be installed at any part of the air duct. The pipe dry separator occupies a smaller area and is more flexible in layout. Dust removal does not need to be considered during the sorting process.

[0022] Due to the working nature of the air duct, the material is very loose when the pipeline dry separator is sorting, which reduces the mechanical inclusion of non-magnetic minerals and produces a higher grade of the secondary concentrate. Non-magnetic minerals are not magnetically attracted by the magnetic plates and pass directly through the pipeline dry separator as secondary tailings.

[0023] Preferably, the wet grinding equipment includes a ball mill, a weak magnetic separator, a concentration magnetic separator and a filter connected in sequence.

[0024] Preferably, it also includes a wet tailings trough, the weak magnetic separator and the concentrating magnetic separator are respectively connected to the wet tailings trough, and the wet tailings trough is connected to a dehydration system.

[0025] The above system can be further optimized:

[0026] Preferably, the fine crusher is a high-pressure roller mill. High-pressure roller mills offer high crushing efficiency, high single-machine output, high fine ore content, small product particle size, low unit energy consumption, and more crushing and less grinding. They offer advantages over conventional fine crushing equipment, particularly in terms of energy conservation throughout the entire mineral processing process.

[0027] Another object of the present invention is to provide a mineral processing process for ultra-low-grade magnetite, comprising the following steps:

[0028] ①Use coarse crusher, medium crusher and fine crusher to crush the ultra-lean magnetite ore in sequence to obtain fine-grained ore;

[0029] ② The fine-grained ore is classified according to the preset particle size by a multi-stage classifier, and separated into three levels of ore powder: above 3mm, 0.5mm-3mm, and below 0.5mm;

[0030] ③ The three levels of ore powder are processed as follows: ore powder larger than 3mm is subjected to magnetic separation by a suspension magnetic separator to obtain the first concentrate and the first tailings; ore powder with a size of 0.5mm-3mm is subjected to magnetic separation by a pipeline dry separator to obtain the second concentrate and the second tailings; ore powder with a size of less than 0.5mm is subjected to magnetic separation by a boiling dry magnetic separator to obtain the third concentrate and the third tailings;

[0031] In the present invention, mineral powders larger than 3mm do not include 3mm, mineral powders between 0.5mm and 3mm include 0.5mm and 3mm, and mineral powders smaller than 0.5mm do not include 0.5mm.

[0032] ④ The first concentrate and the second concentrate are returned to the fine crusher, and then go through the above steps ② and ③ until the third concentrate is obtained, which is the dry concentrate;

[0033] ⑤ The dry concentrate discharged from the boiling dry separator is wet-grinded in the wet grinding equipment to complete the mineral processing.

[0034] The present invention performs coarse, medium and fine crushing on ultra-lean magnetite ore to meet sorting requirements, and then performs multi-stage classification on the fine-grained ore according to preset particle size requirements to obtain ore powder with different particle sizes. The multi-stage classification greatly reduces the power consumption of subsequent wet grinding because most of the tailings have been removed from the finest-grade ore powder, reducing the grinding of tailing components during subsequent grinding. Ore powder with a particle size of more than 3 mm and a particle size of 0.5 mm to 3 mm needs to undergo repeated magnetic separation and fine crushing. Such a reciprocating cycle greatly reduces the content of tailing components, thereby correspondingly reducing the useless power consumption of this part of the tailings.

[0035] It can be seen that the above process mainly optimizes the pre-magnetic separation process, that is, the multi-stage, cyclic crushing and pre-selection are adopted before wet grinding, which greatly reduces the content of tailings, thereby improving the efficiency of subsequent grinding, reducing power consumption and overall mineral processing composition.

[0036] For low-grade magnetite, the following classification method is the best: the ore powder is divided into three particle size levels: 3mm+, 0.5mm-3mm, and below 0.5mm. The ore powder below 0.5mm is magnetically separated using a boiling dry magnetic separator to obtain the third concentrate (dry concentrate), and the third tailings are discharged.

[0037] Different from the prior art, the present invention replaces the original drum magnetic separator for processing mineral powder above 3mm with a suspension magnetic separator for magnetic separation, and replaces the boiling dry magnetic separator for processing mineral powder of 0.5-3mm with a pipeline dry separator for magnetic separation.

[0038] The fluidized bed dry magnetic separator is suitable for magnetic separation of small-particle ores, and this differentiated combination helps keep costs low. The pipeline dry separator is more effective in separating ultra-lean magnetite with 0.5mm-3mm fines, increasing recovery rates by over 5% while reducing wear on the equipment. The pipeline dry separator offers a more flexible layout, saving floor space, and eliminating the need for dust removal during the separation process. Powders larger than 3mm are separated using a suspension magnetic separator, which reduces mechanical inclusions of smaller particles, increases recovery rates by over 5%, and improves magnetic separation efficiency.

[0039] Beneficial effects of the present invention:

[0040] The present invention uses a suspension magnetic separator to separate ultra-lean magnetite ore larger than 3 mm, and a pipeline dry separator to separate ultra-lean magnetite ore between 0.5 and 3 mm. This reduces wear, reduces the equipment footprint, and improves separation efficiency. The pipeline dry separator of the present invention offers more flexible layout, saves floor space, and eliminates the need for dust removal during the separation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of the dry separation process of Example 1 of the present invention.

[0042] Figure 2 This is one of the structural schematic diagrams of the pipeline dry separator of the present invention.

[0043] Figure 3 This is the second structural diagram of the pipeline dry separator of the present invention.

[0044] Figure 4 This is the third structural diagram of the pipeline dry separator of the present invention.

[0045] Figure 5 This is the fourth structural diagram of the pipeline dry separator of the present invention.

[0046] Figure numerals: 1 is a pipeline dry separator; 2 is a suspension magnetic separator; 3 is a boiling dry magnetic separator; 4 is a dispersing classifier; 5 is a high-pressure roller mill; 101 is a rotating air duct; 102 is a screw conveyor; 103 is a discharge scraper; 104 is a magnetic plate; 105 is a discharge port; 106 is a discharge area; 107 is a selection area; the direction of the arrow is the direction of rotation. DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] Example 1

[0049] ①Use coarse crusher and medium crusher to crush the super-lean magnetite ore in sequence. Figure 1 The coarse crushing and medium crushing steps and equipment are omitted in the process), and the ore is crushed by a fine crusher, which is a CLM200 / 180 high pressure roller mill 5, to obtain a fine-grained ore;

[0050] ② The fine-grained ore is classified according to the preset particle size by a multi-stage classifier. There are two multi-stage classifiers, including a KY28000 scattering classifier 4, which separates the ore into three levels of ore powder: above 3mm, 0.5mm-3mm, and below 0.5mm.

[0051] ③ The following treatment is performed on the three levels of ore fines: ore fines larger than 3mm are magnetically separated using a suspension magnetic separator 2, model LJC-15000, with four units in operation; the first concentrate and the first tailings are obtained; the first tailings separated by the suspension magnetic separator 2 are transported to the tailings dry dump, and the selected first concentrate is returned to the high-pressure roller grinding mill 5 for fine crushing, forming a closed circuit;

[0052] Mineral powder of 0.5mm-3mm is magnetically separated by pipeline dry separator 1, and the second concentrate and second tailings are produced after magnetic separation. The second tailings are discarded and transported to the tailings dry discharge yard, and the selected second concentrate is returned to the high pressure roller mill 5 for fine crushing to form a closed circuit.

[0053] Mineral powder below 0.5mm is magnetically separated by a boiling dry magnetic separator 3 to obtain the third concentrate and the third tailings; 18 DMS-B180 boiling dry magnetic separators 3 are selected, the discharged third tailings are transported to the tailings dry discharge yard, and the selected third concentrate (dry concentrate) is transported to the grinding bin and enters the subsequent wet grinding process.

[0054] ④ The first concentrate and the second concentrate are returned to the fine crushing step until all the ore powder is dry concentrate;

[0055] ⑤Wet grinding of dry concentrate is performed to complete mineral processing.

[0056] The present invention mainly improves the dry separation part. The original process replaces the drum magnetic separator that processes ore larger than 3mm with a suspension magnetic separator 2, and replaces the boiling dry magnetic separator 3 that processes 0.5-3mm with a pipeline dry separator 1. The wet grinding process is the same as the original process.

[0057] like Figures 2 to 5 As shown, the pipeline dry separator 1 of the present invention includes a rotating air duct 101 and a motor, the motor is connected to the rotating air duct 101, a magnetic plate 104 is provided on the outside of the rotating air duct 101, the magnetic plate 104 is a tube with an opening, a discharge scraper 103 is provided on the inner wall of the rotating air duct 101, a conveyor is provided inside the rotating air duct 101, the upper end of the conveyor is open, the opening position of the conveyor is opposite to the opening position of the magnetic plate 104, the conveyor is provided with a discharge port 105, and the discharge port 105 is connected to the high-pressure roller grinder 5.

[0058] The rotary air duct 101 of the pipeline dry separator 1 rotates driven by the motor, and the discharge scraper 103 scrapes the materials on the inner wall of the rotary air duct 101 .

[0059] The conveyor is preferably a screw conveyor 102 with an internal screw rod.

[0060] like Figure 4 As shown, according to the opening position of the magnetic plate 104, the pipeline dry separator 1 is divided into a sorting area 107 and a discharge area 106. The area covered by the magnetic plate 104 is the sorting area 107, and the opening position of the magnetic plate 104 (the area not covered by the magnetic plate 104) is the discharge area 106. The discharge scraper 103 is fixed to the outer shell of the screw conveyor 102. The function of the discharge scraper 103 is to scrape off the material on the inner wall of the rotating air duct 101. The discharge scraper 103 is fixed to the discharge area 106 and does not rotate with the rotating air duct 101.

[0061] When the pipeline dry separator 1 is in operation, material enters the rotating air duct 101. Due to the action of the magnetic poles of the outer magnetic plate 104, the magnetite is attracted to the inner wall of the rotating air duct 101. The rotating air duct 101 rotates, carrying the attracted magnetite from the separation area 107 to the discharge area 106. After entering the discharge area 106, the magnetite is unloaded by the discharge scraper 103 and falls into the opening of the screw conveyor 102. It then enters the screw conveyor 102, which transports the magnetite ore (secondary concentrate) to the discharge port 105.

[0062] The Pipeline Dry Separator 1 is more effective in separating ultra-lean magnetite with fines ranging from 0.5mm to 3mm, increasing recovery by over 5% while also reducing wear on the equipment. The Pipeline Dry Separator 1 offers a more flexible layout, saves space, and eliminates the need for dust removal during the separation process.

[0063] Mineral fines larger than 3mm are magnetically separated using a suspended magnetic separator. This reduces mechanical inclusions of smaller particles, increasing recovery by over 5% and boosting magnetic separation efficiency. The maintenance interval for the high-pressure roller grinding rolls has been extended by 20%, reducing equipment failure rates by 5%.

[0064] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present invention.

Claims

1. A beneficiation system for ultra-low-grade magnetite, characterized in that , including a coarse crusher, a medium crusher, a fine crusher, a dry magnetic separator and a wet grinding and separation equipment connected in sequence; The fine crusher is connected to the dry magnetic separator via a multi-stage classifier, and the dry magnetic separator comprises a pipeline dry separator (1), a suspension magnetic separator (2), and a boiling dry magnetic separator (3); the multi-stage classifier is connected to the pipeline dry separator (1), the suspension magnetic separator (2), and the boiling dry magnetic separator (3), respectively.

2. The ultra-low-grade magnetite beneficiation system according to claim 1 is characterized in that The pipeline dry sorting machine (1) includes a rotating air duct (101) and a motor, the motor is connected to the rotating air duct (101), a magnetic plate (104) is arranged on the outside of the rotating air duct (101), the magnetic plate (104) is a tubular structure with an opening, a conveyor is arranged inside the rotating air duct (101), the upper end of the conveyor is open, the opening position of the conveyor is opposite to the opening position of the magnetic plate (104), the conveyor is provided with a discharge port (105), and a discharge scraper (103) is arranged on the conveyor, and the discharge scraper (103) is adapted to the opening at the upper end of the conveyor.

3. The ultra-lean magnetite beneficiation system according to claim 1 is characterized in that The suspended magnetic separator (2) is of the LJC-15000 model, and the boiling dry separator (3) is of the DMS-B180 model.

4. The ore dressing system for ultra-low-grade magnetite according to claim 1 is characterized in that , the multi-stage classifier is a scattering classifier (4).

5. The ultra-low-grade magnetite beneficiation system according to claim 1 is characterized in that An air duct is provided between the multi-stage classifier and the pipeline dry separator (1).

6. The ore dressing system for ultra-low-grade magnetite according to claim 1 is characterized in that The wet grinding and separation equipment includes a ball mill, a weak magnetic separator, a concentration magnetic separator and a filter connected in sequence.

7. The ore dressing system for ultra-low-grade magnetite according to claim 6 is characterized in that , also includes a wet tailings trough, the weak magnetic separator and the thickening magnetic separator are respectively connected to the wet tailings trough, and the wet tailings trough is connected to the dehydration system.

8. The ore dressing process of the ore dressing system for ultra-low-grade magnetite according to claim 1, characterized in that: The following steps are involved: ①Use coarse crusher, medium crusher and fine crusher to crush the ultra-lean magnetite ore in sequence to obtain fine-grained ore; ② The fine-grained ore is classified according to the preset particle size by a multi-stage classifier, and separated into three levels of ore powder: above 3mm, 0.5mm-3mm, and below 0.5mm; ③ The three levels of mineral powder are processed as follows: mineral powder with a size of 3 mm or more is subjected to magnetic separation using a suspension magnetic separator (2) to obtain a first concentrate and a first tailing; mineral powder with a size of 0.5 mm to 3 mm is subjected to magnetic separation using a pipeline dry separator (1) to obtain a second concentrate and a second tailing; mineral powder with a size of 0.5 mm or less is subjected to magnetic separation using a boiling dry magnetic separator (3) to obtain a third concentrate and a third tailing; ④ The first concentrate and the second concentrate are returned to the fine crusher, and then go through the above steps ② and ③ until the third concentrate is obtained, which is the dry concentrate; ⑤ The dry concentrate discharged from the boiling dry separator (3) is subjected to wet grinding by a wet grinding device to complete the mineral separation.

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