Wet type fine grinding and grading system and process method for magnetite concentrate powder

Abstract

The invention discloses a magnetite concentrate powder wet-type fine grinding classification system and process method, and belongs to the technical field of mineral processing. The device comprises a pulp mixing and stirring tank, a discharging port of the pulp mixing and stirring tank is connected with a discharging pump of the pulp mixing and stirring tank, the discharging end of the discharging pump of the pulp mixing and stirring tank is connected with a feeding port of an ore pulp pump pool, and a discharging port of the ore pulp pump pool is connected with an inlet of an ore feeding pump of a hydrocyclone set. An outlet of the hydrocyclone set ore feeding pump is connected with a feeding port of the hydrocyclone set, an underflow port of the hydrocyclone set is connected with a feeding port of the wet-type spiral vertical mill, an ore discharging port of the wet-type spiral vertical mill is provided with an ore pulp grizzly screen device, and an under-screen discharging port of the ore pulp grizzly screen device is connected with a feeding port of the ore pulp pump pool. And a granularity on-line monitoring device is arranged at an overflow port of the hydrocyclone group. The device is less in over-grinding, low in energy consumption, high in grading efficiency and capable of effectively avoiding equipment faults caused by steel ball media.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a wet fine grinding and classification system and process for magnetite concentrate powder. Background Technology

[0002] Fine grinding of magnetite concentrate is a key process for improving iron grade and reducing impurities. Currently, traditional grinding systems mainly adopt the "ball mill + spiral classifier" or "ball mill + hydrocyclone" model, which generally suffers from the following problems: uneven particle size distribution of the grinding product, with serious over-grinding; low classification efficiency, resulting in a large number of qualified fine particles circulating ineffectively within the system, leading to high energy consumption; in addition, the grinding media steel balls are easily discharged with the slurry and enter subsequent pumping and classification equipment, often causing equipment wear, blockage, or even mechanical failure, seriously affecting the system's operating rate.

[0003] Furthermore, the existing fine grinding process for iron concentrate lacks the concept of "selective grinding-precision classification" tailored to the characteristics of magnetite concentrate, resulting in repeated recycling of qualified particle sizes, high unit power consumption, equipment failures caused by steel balls mixed into the slurry, and a significant decrease in overall equipment operating rate. The product particle size distribution is difficult to control, with the proportion of -10μm "mudification" exceeding 20%. Summary of the Invention

[0004] This invention addresses the aforementioned problems and overcomes the shortcomings of existing technologies by providing a wet fine grinding and classification system and process for magnetite concentrate powder. This invention reduces over-grinding, lowers energy consumption, increases classification efficiency, and effectively avoids equipment failures caused by steel ball media.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] This invention provides a wet fine grinding and classification system for magnetite concentrate powder, characterized by comprising a slurry mixing tank, the discharge port of which is connected to a slurry mixing tank discharge pump, the discharge end of which is connected to the inlet of a slurry pump tank, the discharge port of which is connected to the inlet of a hydrocyclone group feed pump, the outlet of which is connected to the inlet of a hydrocyclone group feed pump, the underflow port of which is connected to the inlet of a wet spiral vertical mill, a slurry screen device at the discharge port of the wet spiral vertical mill, the underflow port of which is connected to the inlet of the slurry pump tank, an online particle size monitoring device at the overflow port of the hydrocyclone group, an automatic ball feeder for automatically adding steel balls to the wet spiral vertical mill, and a concentration control system for adjusting the concentration of the slurry entering the hydrocyclone group.

[0007] Furthermore, the diameter of the steel ball media used in the wet spiral vertical mill is 12-20mm.

[0008] Furthermore, the hydrocyclone group consists of 10-24 Φ250mm hydrocyclones connected in parallel.

[0009] Furthermore, the automatic ball feeder automatically replenishes steel ball media based on the current of the wet spiral vertical mill and the product particle size monitored by the online particle size monitoring device.

[0010] Furthermore, the online particle size monitoring device is an ultrasonic online particle size analyzer.

[0011] Furthermore, the concentration control system controls the feed concentration of the hydrocyclone group to 30%-45% through the linkage of an online concentration meter and a water supply valve.

[0012] Furthermore, the slurry screen device is a fixed screen with a screen aperture size of 8mm × 8mm.

[0013] This invention also provides a wet fine grinding and classification process for magnetite concentrate powder, employing the wet fine grinding and classification system for magnetite concentrate powder as described in any one of claims 1-7, characterized by comprising the following steps: S1: Add water to the magnetite concentrate powder in the slurry mixing tank to adjust the concentration to 40%-50%; S2: The slurry after slurry preparation is transported to the slurry pump tank via the discharge pump of the slurry mixing tank; S3: The slurry in the slurry pump pool is fed into the hydrocyclone group for pre-classification by the slurry feed pump of the hydrocyclone group; S4: The overflow of the hydrocyclone group is output as qualified particle size product, and its underflow slurry is fed into the wet spiral vertical mill for fine grinding; S5: The slurry discharged from the wet spiral vertical mill is fed through the slurry screen device to recover the steel balls, and the screened slurry is returned to the slurry pump pool; S6: The slurry returned to the slurry pump pool is fed back into the hydrocyclone group for classification by the slurry pump again, and its underflow returns to the wet spiral vertical mill to form a closed loop. S7: Monitor the overflow product particle size of the hydrocyclone group online using the particle size online monitoring device to ensure that P80≤45μm.

[0014] Furthermore, in step S1, the mechanical stirring action of the slurry mixing tank is used to break up the agglomerates of magnetite concentrate powder, ensuring particle dispersion.

[0015] Furthermore, the inlet pressure of the hydrocyclone assembly is 0.08MPa-0.22MPa.

[0016] The beneficial effects of the present invention.

[0017] This invention achieves uniform and controllable particle size distribution. Through efficient hydrocyclone group classification and online particle size monitoring, it realizes stable control of product particle size (P80≤45μm), effectively reducing over-grinding. The optimized closed-loop system improves classification efficiency, reduces the circulating load of qualified fine particles, and lowers unit power consumption. Operation is stable and reliable. The slurry screen device effectively recovers steel balls discharged from the mill, preventing them from entering the pumping system, avoiding equipment wear and malfunctions, and improving operating efficiency. It integrates online particle size and concentration monitoring with automatic ball addition, offering a high degree of automation, facilitating process adjustment and operation, and improving production stability. The process is compact and suitable for industrial-scale deep fine grinding of magnetite concentrate powder, demonstrating strong practicality. Attached Figure Description

[0018] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] Figure 1 This is a diagram showing the equipment connections for the hierarchical system of this invention.

[0020] Figure 2 This is a process flow diagram of the fine grinding and classification process of the present invention.

[0021] The markings in the diagram are as follows: 1 is the slurry mixing tank, 2 is the wet spiral vertical mill, 3 is the hydrocyclone group, 4 is the slurry screen device, 5 is the slurry pump pool, 6 is the discharge pump of the slurry mixing tank, 7 is the feed pump of the hydrocyclone group, 8 is the automatic baller, 9 is the online particle size monitoring device, and 10 is the concentration control system. Detailed Implementation

[0022] Combined with appendix Figure 1 As shown, this embodiment provides a wet fine grinding and classification system for magnetite concentrate powder, including a slurry mixing tank 1. The outlet of the slurry mixing tank 1 is connected to a slurry mixing tank discharge pump 6, which pumps the uniformly prepared slurry with a concentration of 40%-50% to subsequent processes. The slurry mixing tank 1 effectively disperses agglomerates of magnetite concentrate powder through mechanical stirring, ensuring particle dispersion.

[0023] The discharge end of the slurry mixing tank discharge pump 6 is connected to the inlet of the slurry pump tank 5, thereby inputting qualified slurry into the slurry pump tank 5 for collection. The slurry pump tank 5 also receives slurry from the system circulation, and its discharge port is connected to the inlet of the hydrocyclone assembly to the slurry pump 7, providing conveying power for the slurry classification operation.

[0024] The outlet of the hydrocyclone group's feed pump 7 is connected to the feed inlet of the hydrocyclone group 3, pumping the slurry into it at a pressure of 0.08MPa-0.22MPa for classification. The hydrocyclone group 3 achieves pre-classification and inspection classification of the slurry through centrifugal force. Its overflow outlet discharges qualified fine particles, and an online particle size monitoring device 9 is installed at this point to monitor the product particle size index (such as P80 value). Its underflow outlet is connected to the feed inlet of the wet spiral vertical mill 2, sending coarse slurry into the mill for fine grinding.

[0025] The wet spiral vertical mill 2 uses steel balls with a diameter of 12-20mm as grinding media to grind coarse particles at a grinding concentration of 60%-70%. A slurry screen device 4 is installed at the mill discharge port to intercept and recover the steel balls discharged with the slurry, preventing them from entering subsequent processes and causing equipment wear. The undersize discharge port of this screen device is connected to the feed port of the slurry pump pool 5, allowing the undersize slurry to return to the pump pool, forming a closed-loop grinding and classification cycle together with the hydrocyclone group feed pump 7, the hydrocyclone group 3, and the wet spiral vertical mill 2.

[0026] The system is also equipped with an automatic ball feeder 8, which can automatically add steel balls according to the mill current and product particle size feedback; and a concentration control system 10, which controls the feed concentration of the hydrocyclone group at 30%-45% through the linkage of an online concentration meter and a water supply valve, so as to achieve stable control of process parameters.

[0027] like Figure 2 As shown, the process method using the above system is carried out according to the following steps: Step S1: Add water to the magnetite concentrate powder in the slurry mixing tank 1 to adjust the concentration to 40%-50%. This step uses mechanical stirring to break up the particle agglomerates in the raw material, ensuring the formation of a uniform and stable suspension slurry, providing consistent feed conditions for subsequent grinding and classification.

[0028] Step S2: The slurry after conditioning is transported to the slurry pump tank 5 via the discharge pump 6 from the conditioning mixing tank. This step achieves the transfer and collection of qualified slurry.

[0029] Step S3: The slurry in the slurry pump pool 5 is fed into the hydrocyclone group 3 at an inlet pressure of 0.08MPa-0.22MPa via the feed pump 7 of the hydrocyclone group for pre-classification. This step utilizes the centrifugal force field of the hydrocyclone to quickly separate some qualified particles that have reached the target fineness (P80≤45μm), allowing them to be pre-discharged from the overflow port as product, thereby reducing the amount of material entering the mill and lowering the load and over-grinding risk in subsequent grinding stages.

[0030] Step S4: The overflow of the hydrocyclone group 3 is output as qualified particle size product; its underflow slurry is fed into the wet spiral vertical mill 2 for fine grinding, and the grinding concentration is controlled at 60%-70%. This step is a key step in achieving the final fineness of the product by specifically grinding the coarse particles generated after classification and reducing their particle size using steel ball media at a suitable concentration.

[0031] Step S5: The slurry discharged from the wet spiral vertical mill 2 passes through the slurry screen device 4 to recover the steel balls, and the undersized slurry is returned to the slurry pump pool 5. The core function of this step is to achieve effective recovery and recycling of the steel ball media, prevent the steel balls from entering the slurry pumping system, avoid equipment wear, blockage and other failures caused by this, and ensure continuous and stable operation of the system.

[0032] Step S6: The slurry returned to the slurry pump pool 5 is fed back into the hydrocyclone group 3 via the hydrocyclone group feed pump 7 for classification. The underflow returns to the wet spiral vertical mill 2, forming a closed-loop cycle. This step constitutes a closed-loop "grinding-classification" system, allowing substandard coarse particles to continuously return for regrinding, while qualified fine particles are promptly separated. This significantly improves classification efficiency and the selectivity of the entire system, ensuring the uniformity of the final product's particle size.

[0033] Step S7: The particle size of the overflow product from the hydrocyclone group 3 is monitored online by the particle size online monitoring device 9 to ensure P80 ≤ 45μm; the feed concentration is controlled at 30%-45% by the concentration control system 10; and steel balls are automatically added by the automatic ball feeder 8 according to the mill current and product particle size. This step integrates online monitoring and automatic control of three key parameters: product particle size, feed concentration, and mill media. It realizes closed-loop intelligent control of the grinding and classification process, ensures long-term stability of product quality, and helps optimize energy consumption and media consumption.

[0034] This system and method achieves efficient, energy-saving, and stable fine grinding of magnetite concentrate by constructing a closed-loop system that closely coordinates processes such as slurry preparation, classification, fine grinding, media recovery, and online control. It effectively solves problems in traditional processes such as difficulty in particle size control, severe over-grinding, high energy consumption, and high equipment failure rates. It possesses outstanding advantages such as controllable particle size, low over-grinding rate, energy saving, and reliable operation, and has broad applicability and promising prospects in the field of deep processing of magnetite concentrate.

[0035] It is understood that the above specific description of the present invention is only for illustrating 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 modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A wet fine grinding and classification system for magnetite concentrate powder, characterized in that, The system includes a slurry mixing tank (1), the outlet of which is connected to a slurry mixing tank discharge pump (6), the outlet of which is connected to the inlet of a slurry pump tank (5), the outlet of which is connected to the inlet of a hydrocyclone feed pump (7), the outlet of which is connected to the inlet of a hydrocyclone group (3), and the underflow outlet of which is connected to the inlet of a wet spiral vertical mill (2). The wet spiral vertical mill (2) is equipped with a slurry screen device (4) at its discharge port. The under-screen discharge port of the slurry screen device (4) is connected to the feed port of the slurry pump pool (5). The overflow port of the hydrocyclone group (3) is equipped with an online particle size monitoring device (9). The system is also equipped with an automatic ball feeder (8) for automatically adding steel balls to the wet spiral vertical mill (2) and a concentration control system (10) for adjusting the concentration of the slurry entering the hydrocyclone group (3).

2. The wet fine grinding and classification system for magnetite concentrate powder according to claim 1, characterized in that, The diameter of the steel ball media used in the wet spiral vertical mill (2) is 12-20mm.

3. The wet fine grinding and classification system for magnetite concentrate powder according to claim 1, characterized in that, The hydrocyclone group (3) consists of 10-24 Φ250mm hydrocyclones connected in parallel.

4. The wet fine grinding and classification system for magnetite concentrate powder according to claim 1, characterized in that, The automatic ball feeder (8) automatically adds steel ball media based on the current of the wet spiral vertical mill (2) and the product particle size monitored by the particle size online monitoring device (9).

5. The wet fine grinding and classification system for magnetite concentrate powder according to claim 1, characterized in that, The particle size online monitoring device (9) is an ultrasonic online particle size analyzer.

6. The wet fine grinding and classification system for magnetite concentrate powder according to claim 1, characterized in that, The concentration control system (10) controls the feed concentration of the hydrocyclone group (3) to be 30%-45% by means of an online concentration meter and a water supply valve.

7. The wet fine grinding and classification system for magnetite concentrate powder according to claim 1, characterized in that, The slurry screen device (4) is a fixed screen with a screen hole size of 8mm×8mm.

8. A wet fine grinding and classification process for magnetite concentrate powder, employing the wet fine grinding and classification system for magnetite concentrate powder as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Add water to the magnetite concentrate powder in the slurry mixing tank (1) and adjust the concentration to 40%-50%; S2: The slurry after slurry preparation is transported to the slurry pump pool (5) through the discharge pump (6) of the slurry mixing tank. S3: The slurry in the slurry pump pool (5) is fed into the hydrocyclone group (3) for pre-classification by the slurry pump (7) of the hydrocyclone group; S4: The overflow of the hydrocyclone group (3) is output as qualified particle size product, and its underflow slurry is fed into the wet spiral vertical mill (2) for fine grinding; S5: The slurry discharged from the wet spiral vertical mill (2) is fed through the slurry screen device (4) to recover the steel balls, and the slurry under the screen is returned to the slurry pump pool (5). S6: The slurry returned to the slurry pump pool (5) is fed into the hydrocyclone group (3) again through the hydrocyclone group feed pump (7) for classification, and its underflow returns to the wet spiral vertical mill (2) to form a closed loop; S7: Monitor the overflow product particle size of the hydrocyclone group (3) online through the particle size online monitoring device (9) to ensure that P80≤45μm.

9. The wet fine grinding and classification process for magnetite concentrate powder according to claim 8, characterized in that, In step S1, the mechanical stirring action of the slurry mixing tank (1) is used to break up the agglomerates of magnetite concentrate powder to ensure particle dispersion.

10. The wet fine grinding and classification process for magnetite concentrate powder according to claim 8, characterized in that, The inlet pressure of the hydrocyclone assembly (3) is 0.08MPa-0.22MPa.

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