A control method for a lead-zinc ore classification system

Abstract

The application relates to a control method of a lead-zinc ore grading system, which comprises the following steps: controlling a ball mill to grind the lead-zinc ore and discharge the grinding product into a spiral classifier, controlling the spiral classifier to add discharge water to the grinding product to obtain slurry, controlling the spiral classifier to perform first grading on the slurry to obtain regrinding product and overflow product, sending the overflow product to a high-frequency vibration fine screen, and sending the regrinding product back to the ball mill for regrinding; controlling the high-frequency vibration fine screen mesh to perform second grading on the overflow product to obtain oversize product and undersize product, sending the oversize product back to the ball mill for regrinding, and sending the undersize product into a flotation machine for flotation. By adjusting the discharge water, the spiral classifier performs the first grading, and by adjusting the high-frequency vibration fine screen mesh aperture, the second grading is performed according to the particle size, the method improves the processing capacity and the grading efficiency, realizes accurate grading, discharges as many qualified products as possible, reduces mutual entanglement of ore particles to cause overgrinding, and avoids affecting process indexes.

Description

Technical Field

[0001] This application relates to the field of mineral processing and classification technology, and in particular to a control method for a lead-zinc ore classification system. Background Technology

[0002] In grinding circuits, classification methods are basically divided into two categories. One is to classify materials according to the settling law of particles in the fluid by using gravity or centrifugal force. Commonly used equipment includes spiral classifiers, hydrocyclones, cone classifiers, and trough classifiers. The other is to classify materials according to particle size by controlling the screen aperture size. Commonly used equipment includes vibrating screens, arc screens, and fine screens.

[0003] Lead-zinc ore is characterized by high lead, zinc, and sulfur content, and is easy to grind but difficult to liberate. The grinding and classification method uses a closed-circuit grinding system consisting of a mill and a spiral classifier. This method has low classification efficiency and low classification accuracy, resulting in the re-enrichment of qualified mineral particles in the return sand. In particular, minerals such as galena, sphalerite, and pyrite have high density. Some qualified mineral particles, due to their small particle size and slow settling velocity, are easily carried away by the unqualified mineral particle group and cannot be discharged from the overflow port in time. Instead, they are re-enriched in the return sand and enter the mill for secondary grinding, resulting in over-grinding and affecting the indicators of the beneficiation method. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, this application provides a control method for a lead-zinc ore classification system. This method can solve the technical problem that qualified ore particles from grinding are trapped and cannot be removed in time, and are re-enriched in the return sand and enter the mill for secondary grinding, causing over-grinding and affecting the indicators of the beneficiation method.

[0005] The first aspect of this application provides a control method for a lead-zinc ore classification system, applied to a lead-zinc ore classification system. The system includes a ball mill, a spiral classifier, and a high-frequency vibrating fine screen. The screen layout of the high-frequency vibrating fine screen is: 0.15mm aperture screen: 0.18mm aperture screen = 2:1. The method includes the following steps:

[0006] First, the ball mill is controlled to grind the lead-zinc ore, and the grinding product is discharged into the spiral classifier. The spiral classifier is then controlled to add discharge water to the grinding product to obtain a slurry. The discharge water flow rate is 15 m³ / s. 3 / h-30m 3 / h, the slurry concentration is 70%-75%, and the particle size is +200 mesh 50-60%, -200 mesh 40-50%, and -500 mesh 20-25%;

[0007] Secondly, the spiral classifier is controlled to perform the first classification of the slurry to obtain the re-grinding product and the overflow product. The overflow product is sent to the high-frequency vibrating fine screen, and the re-grinding product is sent back to the ball mill for re-grinding. The concentration of the overflow product is 60-70%, and the particle size is +200 mesh 50-60%, -200 mesh 35-45%, and -500 mesh 15-20%.

[0008] Finally, the overflow product is classified a second time by controlling a high-frequency vibrating fine screen to obtain the oversize product and the undersize product. The oversize product is sent back to the ball mill for re-grinding, and the undersize product is fed into the flotation machine for flotation. The concentration of the undersize product is 40-45%, and the particle size is +200 mesh 30-35%, -200 mesh 68-72%, and -500 mesh 30-35%.

[0009] Optionally, in some embodiments of the first aspect,

[0010] The second grading is based on particle size evaluation criteria to determine the grading results. The particle size evaluation criteria include the proportion of the first target, the proportion of the second target, and the proportion of the third target. The proportion of the first target is less than 35%, the proportion of the second target is greater than 68%, and the proportion of the third target is less than 35%. The proportion of the first target is the content of +200 mesh, the proportion of the second target is the content of -200 mesh, and the proportion of the third target is the content of -500 mesh.

[0011] Optionally, in some embodiments of the first aspect,

[0012] The spiral classifier is controlled to rotate at a target speed to push the re-ground product upwards and discharge it into the first chute, from where it returns to the ball mill for re-grinding.

[0013] Optionally, in some embodiments of the first aspect,

[0014] The spiral classifier controls the overflow product to be discharged into the slurry pump pool through the second chute. The slurry pump pool is equipped with a slurry pump, and the overflow product is pumped to a high-frequency vibrating fine screen for secondary classification.

[0015] Optionally, in some embodiments of the first aspect,

[0016] The high-frequency vibrating fine screen is controlled to send the product on the screen to the ball mill for re-grinding through the third chute, and the product under the screen is sent to the flotation machine for flotation through the fourth chute.

[0017] Optionally, in some embodiments of the first aspect,

[0018] The spiral classifier adjusts the overflow fineness of the first stage by adjusting the concentration of the slurry; the concentration of the slurry is negatively correlated with the overflow fineness.

[0019] Optionally, in some embodiments of the first aspect,

[0020] Controlling the high-frequency vibrating fine screen to vibrate at the target frequency allows the high frequency to disrupt the surface tension and fine particles of the overflow product, accelerating the separation of high-density materials in the overflow product and increasing the probability of low-density materials in the overflow product contacting the screen openings of the high-frequency vibrating fine screen.

[0021] The technical solution provided in this application may include the following beneficial effects:

[0022] This application provides a control method for a lead-zinc ore classification system. By combining the advantages of gravity classification and particle size classification, a new classification process is formed. By adjusting the discharge water, the spiral classifier initially classifies unqualified mineral particles with larger particle sizes and faster settling speeds from basically qualified mineral particles. The basically qualified mineral particles are pumped to a high-frequency vibrating fine screen. By adjusting the screen aperture, precise classification according to particle size is achieved. This method increases the throughput and classification efficiency, achieves precise classification, discharges as many qualified products as possible, reduces the mutual entanglement of mineral particles leading to over-grinding, and avoids affecting process parameters.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0024] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0025] Figure 1 This is a schematic flowchart illustrating the control method in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the lead-zinc ore grading system structure shown in the embodiments of this application. Detailed Implementation

[0027] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0028] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0032] Figure 1 This is a schematic flowchart illustrating the control method in an embodiment of this application;

[0033] like Figure 1 The control method of the lead-zinc ore classification system shown is applied to, for example... Figure 2 The lead-zinc ore classification system shown includes a ball mill, a spiral classifier, and a high-frequency vibrating fine screen.

[0034] The control method for lead-zinc ore classification systems includes the following steps:

[0035] S1. Control the ball mill to grind lead-zinc ore and discharge the ground product into the spiral classifier. Control the spiral classifier to add discharge water to the ground product to obtain slurry. The crushed ore product is fed into the ball mill by a belt conveyor for grinding. The concentration of the slurry before classification is 70%-75%, with a particle size of +200 mesh accounting for 50-60%, -200 mesh accounting for 40-50%, and -500 mesh accounting for 20-25%.

[0036] S2. Control the spiral classifier to perform the first classification of the slurry, obtain the re-grinding product and the overflow product, send the overflow product to the high-frequency vibrating fine screen, and send the re-grinding product back to the ball mill for re-grinding.

[0037] The spiral classifier process: After the ground product is fed into the spiral classifier through a chute, the classifier utilizes the principle that mineral particles of different sizes and specific gravities settle at different speeds in the liquid. Fine mineral particles float in the water, generating overflow product. The spiral classifier controls the spiral classifier to discharge the overflow product through a second chute into a slurry pump tank. A slurry pump in the slurry pump tank sends the overflow product to a high-frequency vibrating fine screen for secondary classification. Coarse mineral particles settle at the bottom of the trough to produce a re-grinding product. The spiral classifier's spiral blades are controlled to rotate at a target speed to push the re-grinding product upwards and discharge it into the first chute, from where it returns to the ball mill for re-grinding.

[0038] The spiral classifier adjusts the slurry concentration by regulating the flow rate of the discharge water added to the grinding product. This slurry concentration, in turn, adjusts the overflow fineness of the first stage. There is a negative correlation between slurry concentration and overflow fineness; lower slurry concentration results in higher overflow fineness. Generally, smaller particles settle more slowly and are more easily discharged from the overflow outlet. However, in actual classification, some small particles are carried along and settle rapidly, then discharged back into the ball mill via the spiral conveyor from the return sand outlet, causing over-grinding.

[0039] This method adjusts the discharge water flow rate of the ball mill to adjust the slurry concentration and overflow fineness. After multiple tests, the ball mill discharge water flow rate of 20m³ / h in the current method was adjusted. 3 / h-35m 3 / h, reduced to 15m 3 / h-30m 3 The concentration of overflow product is increased from 45-50% in the current method to 60-70% per hour. This effectively improves the settling rate of small particles in the first stage and avoids over-grinding of small particles.

[0040] After the first grading, the concentration of the overflow product is 60-70%, with +200 mesh accounting for 50-60%, -200 mesh accounting for 35-45%, and -500 mesh accounting for 15-20%.

[0041] S3. Control the high-frequency vibrating fine screen to perform a second classification of the overflow product, obtaining oversize and undersize products. The oversize product is sent back to the ball mill for regrinding, and the undersize product is sent to the flotation machine for flotation. Specifically, control the high-frequency vibrating fine screen to send the oversize product to the ball mill for regrinding through the third chute, and send the undersize product to the flotation machine for flotation through the fourth chute. The screen layout of the high-frequency vibrating fine screen is: 0.15mm aperture screen: 0.18mm aperture screen = 2:1.

[0042] High-frequency vibrating fine screening classification process: High frequency is used to break the surface tension of the slurry and the high-speed oscillation of fine materials on the screen surface, which accelerates the separation of useful minerals with relatively high density, increases the probability of materials smaller than the separation particle size contacting the screen holes, and creates better separation conditions, so that materials smaller than the separation particle size, especially high-density materials, pass through the screen holes together with the slurry.

[0043] The second grading is based on particle size assessment criteria, which include the proportion of the first target, the proportion of the second target, and the proportion of the third target. The proportion of the first target is less than 35%, the proportion of the second target is greater than 68%, and the proportion of the third target is less than 35%. The first target proportion is the percentage of +200 mesh content, the second target proportion is the percentage of -200 mesh content, and the third target proportion is the percentage of -500 mesh content. In other words, the higher the proportion of -200 mesh content, the better, and the lower the proportions of +200 mesh content and -500 mesh content, the better.

[0044] The undersize product is the final graded product, with a concentration of 40%-45%, and particle sizes of +200 mesh accounting for 30-35%, -200 mesh accounting for 68-72%, and -500 mesh accounting for 30-35%.

[0045] Y Plant's ore is characterized by high lead, zinc, and sulfur content, and is easy to grind but difficult to liberate. In the existing process, qualified mineral particles are re-enriched in the return sand. In particular, minerals such as galena, sphalerite, and pyrite have high density. Some qualified mineral particles are easily entrained by unqualified mineral particles due to their small particle size and slow settling velocity. They cannot be discharged from the overflow port in time, but instead are re-enriched in the return sand and enter the mill for secondary grinding, resulting in over-grinding and affecting the beneficiation process indicators.

[0046] Before the classification process was upgraded, the grinding and classification efficiency consistently hovered between 35% and 45%, and the classification overflow products still exhibited a 1:1:1 distribution ratio, with +200 mesh content approximately 35% and -500 mesh content approximately 36%, a high proportion forming a "dumbbell-shaped" distribution. This meant a high content of undissociated coarse particles and over-ground fine particles, which was a key factor restricting the improvement of mineral processing indicators. After classification based on this control method, the classification overflow products basically followed a normal distribution, with +200 mesh content approximately 30% and -500 mesh content approximately 30%. The classification efficiency improved by 12.99%, the lead and zinc content in the tailings decreased by 30%, the lead recovery rate increased by 0.2%, and the zinc recovery rate increased by 0.35%, resulting in an annual profit of over 6 million yuan.

[0047] Finally, it should be noted that in this document, relationships such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "include," "contain," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0048] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0049] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A control method for a lead-zinc ore classification system, characterized in that: This method is applied to a lead-zinc ore grading system, which includes a ball mill, a spiral classifier, and a high-frequency vibrating fine screen. The screen layout of the high-frequency vibrating fine screen is: 0.15mm aperture screen : 0.18mm aperture screen = 2:

1. The method includes the following steps: The ball mill is controlled to grind lead-zinc ore and discharge the grinding product into the spiral classifier. The spiral classifier is then controlled to add discharge water to the grinding product to obtain a slurry, wherein the discharge water flow rate is 15 m³ / s. 3 / h-30m 3 / h, the concentration of the slurry is 70%-75%, and the particle size is +200 mesh 50-60%, -200 mesh 40-50%, and -500 mesh 20-25%; The spiral classifier is controlled to perform the first classification of the slurry to obtain a re-grinding product and an overflow product. The overflow product is sent to a high-frequency vibrating fine screen, and the re-grinding product is sent back to the ball mill for re-grinding. The overflow product has a concentration of 60-70%, and the particle size is 50-60% for +200 mesh, 35-45% for -200 mesh, and 15-20% for -500 mesh. The high-frequency vibrating fine screen is controlled to perform a second classification of the overflow product, resulting in oversize and undersize products. The oversize product is sent back to the ball mill for re-grinding, and the undersize product is fed into a flotation machine for flotation. The concentration of the undersize product is 40-45%, and the particle size distribution is as follows: +200 mesh accounts for 30-35%, -200 mesh accounts for 68-72%, and -500 mesh accounts for 30-35%.

2. The control method according to claim 1, characterized in that, The second grading is based on the particle size evaluation criteria to determine the grading result. The particle size evaluation criteria include a first target percentage, a second target percentage, and a third target percentage. The first target percentage is less than 35%, the second target percentage is greater than 68%, and the third target percentage is less than 35%. The first target percentage is the percentage of +200 mesh content, the second target percentage is the percentage of -200 mesh content, and the third target percentage is the percentage of -500 mesh content.

3. The control method according to claim 1, characterized in that, The spiral blades of the spiral classifier are controlled to rotate at a target speed to push the re-ground product upward and discharge it into the first chute, and then return it to the ball mill for re-grinding through the first chute.

4. The control method according to claim 1, characterized in that, The spiral classifier controls the overflow product to be discharged into the slurry pump pool through the second chute. The slurry pump pool is equipped with a slurry pump, and the overflow product is pumped to the high-frequency vibrating fine screen for the second classification.

5. The control method according to claim 1, characterized in that, The high-frequency vibrating fine screen is controlled to send the product on the screen to the ball mill for re-grinding through the third chute, and the product under the screen is sent to the flotation machine for flotation through the fourth chute.

6. The control method according to claim 1, characterized in that, The spiral classifier adjusts the overflow fineness of the first classifier by adjusting the concentration of the slurry, and the concentration of the slurry is negatively correlated with the overflow fineness.

7. The control method according to claim 1, characterized in that, The high-frequency vibrating fine screen is controlled to vibrate at a target frequency so that the high frequency breaks down the surface tension and fine particles of the overflow product, accelerates the separation of high-density materials in the overflow product, and increases the probability of low-density materials in the overflow product contacting the screen openings of the high-frequency vibrating fine screen.

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