A variable grinding and separation process for magnetic and hematite

Abstract

The present invention discloses a variable grinding process for magnetite and hematite, belonging to the technical field of iron ore beneficiation. The present invention adopts a closed-circuit grinding overflow control classification operation, so that the fineness of the overflow product after the first grinding and classification operation meets the requirements of the separation conditions. The closed-circuit grinding overflow control classification operation equipment consists of a ball mill, a spiral classifier, and a hydrocyclone. The hydrocyclone is controlled and classified through the overflow of the grinding classification, which reduces the number of mills and simplifies the configuration, avoiding the problems of large classification area and low classification accuracy of the traditional control classification using a spiral classifier; through the variable process, the needs of separate magnetite production, separate hematite production and mixed production of magnetic hematite are realized to obtain corresponding iron concentrate products, thereby improving the adaptability of the grinding process of the main grinding equipment under the changes in the properties of different batches of raw ore, achieving flexible production, fully utilizing the production capacity of the process equipment, and improving efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of iron ore dressing, in particular to a variable grinding separation process for magnetic and hematite ore. Background Art

[0002] Some iron mines have many mining sites, but the magnetic iron content of iron ore at each mining site varies greatly, especially in underground mines, which makes ore matching difficult, resulting in unstable magnetic iron content in batch ore output; or due to changes in geological conditions, the output of ore is reduced, resulting in a reduction in the amount of ore entering the beneficiation plant and insufficient production capacity, forcing the beneficiation plant to process purchased ore. However, the raw ore varieties of each batch of market-based purchased ore are different, and the raw ore grade, magnetic iron content and selectivity are very unstable. The fixed mineral processing production process cannot meet the processing requirements of the changing properties of the raw ore. Therefore, a variable grinding process must be developed to meet the existing basic processing process and processing requirements of magnetic ore, hematite and their mixed ores. Summary of the Invention

[0003] The purpose of the present invention is to provide a variable grinding process for magnetic and hematite ore, improve the adaptability of the grinding process equipment when the properties of the raw ore in different batches change, achieve flexible production, and maximize the production capacity of the process equipment to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A variable grinding separation process for magnetic and hematite ore, comprising the following steps:

[0006] S1: A closed-circuit grinding overflow-controlled classification operation is used: the raw ore is fed into the ball mill for grinding, then enters the spiral classifier for inspection and classification. The sand returned by the spiral classifier is returned to the ball mill for re-grinding. The overflow product of the spiral classifier enters the hydrocyclone for controlled classification. The sand is set in the hydrocyclone and returned to the ball mill for re-grinding. The overflow of the hydrocyclone enters the separation process.

[0007] S2: The hydrocyclone controls the overflow of the classification to enter the variable process for sorting according to the different properties of the processed minerals. The variable process sorting operation is divided into three production processes: single magnetite production, single hematite production, and mixed hematite production. The three production processes are switched at the variable switching points according to the different properties of the raw ore. There are four variable switching points in the variable process, all of which are controlled by electric slurry valves. Each electric slurry valve has one opening and closing point, namely 1# opening and closing point, 2# opening and closing point, 3# opening and closing point, and 4# opening and closing point.

[0008] S3: When producing magnetite alone, the grinding and grading operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 1# and 4# opening and closing points in the variable process and opening the 2# and 3# opening and closing points in the process to realize the independent production of magnetite.

[0009] S4: When producing hematite alone, the grinding and grading operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 2# and 3# opening and closing points in the variable process and opening the 1# and 4# opening and closing points to realize the single production process of hematite.

[0010] S5: When producing mixed hematite ore, the grinding and grading operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 1# and 3# opening and closing points in the variable process, and opening the 2# and 4# opening and closing points to realize the production process of mixed hematite ore with magnetic first and hematite later.

[0011] Furthermore, the closed-circuit grinding overflow control and grading equipment in S1 consists of a ball mill, a spiral classifier, and a hydrocyclone. The sand returned from the spiral classifier and the sand settling in the hydrocyclone are returned to the ball mill for regrinding, and the grinding products after grinding with the original ore are circulated into the inspection grading and control grading; the overflow from the spiral classifier inspection grading is then controlled and graded by the hydrocyclone, and the overflow from the hydrocyclone is the final grinding grading overflow product.

[0012] Furthermore, the hydraulic overflow material controlled and classified by the hydrocyclone in S2 is in the form of a flowable slurry, which is transported through pipelines in a variable process.

[0013] Furthermore, the 1# opening and closing points and the 2# opening and closing points in S2 are set between the hydrocyclones in the variable process to control the classification overflow and enter the separation process, that is, the front end of the separate hematite production process; the 3# opening and closing points and the 4# opening and closing points are set between the separate magnetite production process in the variable process after the rough and selected tailings are merged and the separate hematite production process, that is, the front end of the separate hematite production process.

[0014] Furthermore, the production process flow of the single magnetite in S2 is: the hydrocyclone controls the classification overflow to carry out two separations, one is the magnetite roughing, the second is the roughing concentrate and then the magnetite concentration, the concentrated concentrate is the final magnetite concentrate, and the primary magnetite roughing tailings and the secondary magnetite concentration tailings are combined into the total tailings.

[0015] Furthermore, the production process flow of hematite alone in S2 is as follows: the hydrocyclone controls the overflow of the classification to enter the roughing slag screen for impurities removal, the bottom of the slag screen enters the strong magnetic roughing, the strong magnetic roughing tailings are concentrated by the roughing tailings thickener and then enter the scavenging slag screen for slag separation, the bottom of the slag screen enters the strong magnetic scavenging, the strong magnetic roughing concentrate and the strong magnetic scavenging concentrate are combined into hematite concentrate, and the top of the roughing slag screen and the scavenging slag screen are combined with the scavenging tailings to enter the total tailings.

[0016] Furthermore, the production process of the magnetic hematite mixed ore in S2 is a magnetic first and hematite later separation production process: the hydrocyclone controls the classification overflow to first enter the magnetite production process, and after two separations of magnetite roughing and concentrating, the magnetite concentrate is pre-selected; the tailings of the magnetite roughing and concentrating, namely the hematite, are merged and entered into the hematite production process for separation; the magnetite concentrate and hematite concentrate produced by the magnetic hematite mixed ore can be two concentrate products separately, or mixed into one magnetic hematite mixed concentrate product.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a variable grinding process for magnetic and hematite, which reduces the grinding configuration, first inspects and grades the grinding products in a spiral classifier, inspects the grading overflow, and then uses a hydrocyclone to control the grading, thereby improving the grading accuracy and meeting the separation fineness requirements. In addition, the present invention utilizes an organic combination of weak magnetic separation equipment and strong magnetic separation equipment, and realizes a set of grinding process flows that adapt to processing techniques and product classifications with different raw ore properties through process flow switching, thereby improving the adaptability of the grinding process of the main grinding equipment under changes in the properties of different batches of raw ores, achieving flexible production grouping, maximizing the production capacity of the process equipment, and improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of the variable grinding process for magnetic and hematite ore of the present invention;

[0020] Figure 2 This is a flow chart of the separate magnetite production process of the present invention;

[0021] Figure 3 This is a flow chart of the single hematite production process of the present invention;

[0022] Figure 4 The present invention is a flow chart of the production process of the mixed hematite ore. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] See also Figure 1-4 In the embodiment of the present invention, a variable grinding process for magnetic and hematite ore is provided, which is applicable to the grinding and processing process of raw ore with varying magnetic iron content in the selected batches of small and medium-sized ore concentrators. The specific steps are as follows:

[0025] S1: If Figure 1 As shown: The grinding process adopts a closed-circuit grinding overflow control classification operation, so that the fineness of the overflow product after the first stage of grinding and classification operation meets the requirements of the selection conditions, reducing the number of grinding stages; the equipment for the closed-circuit grinding overflow control classification operation consists of a ball mill, a spiral classifier, and a hydrocyclone. Specifically, the raw ore is fed into the ball mill for grinding, and then enters the spiral classifier for inspection and classification. The sand returned by the spiral classifier is returned to the ball mill for re-grinding; the overflow product of the spiral classifier is then sent to the hydrocyclone for control classification, avoiding the problems of large classification area and low classification accuracy of the traditional control classification using the spiral classifier. The sand settling in the hydrocyclone is also returned to the ball mill for re-grinding, and the overflow of the hydrocyclone enters the selection process.

[0026] Among them, the return sand of the spiral classifier and the sedimentation sand of the hydrocyclone are returned to the ball mill for regrinding, and the grinding products after grinding with the original ore are circulated into the inspection classification and control classification; the overflow of the spiral classifier inspection classification is then passed through the hydrocyclone control classification, and the overflow of the hydrocyclone is the final grinding classification overflow product.

[0027] S2: If Figure 1 As shown in the figure: the hydrocyclone controls the classification overflow to enter the variable process for sorting operation according to the different properties of the processed minerals. Among them, the hydraulic overflow material is in the form of flowable slurry, which is transported through pipelines in the variable process. The variable process sorting operation is divided into three production process flows: separate magnetite production, separate hematite production and mixed hematite production. The change switching points of the three production process flows in the variable process are switched according to the different properties of the original ore. There are 4 change switching points in the variable process, all of which are controlled by electric slurry valves for opening and closing. Each electric slurry valve has 1 opening and closing point. For easy distinction, the electric slurry valves that are changed and switched in the process are numbered as: 1# opening and closing point, 2# opening and closing point, 3# opening and closing point and 4# opening and closing point.

[0028] Among them, the 1# opening and closing points and the 2# opening and closing points are set between the hydrocyclones in the variable process to control the classification overflow and enter the separation process, that is, the front end of the separate hematite production process; the 3# opening and closing points and the 4# opening and closing points are set between the separate magnetite production process in the variable process after the rough and concentrated tailings are merged and the separate hematite production process, that is, the front end of the separate hematite production process.

[0029] The process for producing magnetite alone involves two separate separations: a hydrocyclone controls the overflow from the grading process, with the first separation being the magnetite rougher and the second separation being the rougher concentrate, which is then subjected to magnetite concentrating. The concentrate is then used as the final magnetite concentrate. The tailings from the primary rougher and secondary magnetite concentrating processes are combined into the total tailings.

[0030] The production process for hematite ore alone is as follows: overflow from the hydrocyclone controls the grading process and enters the roughing screen for impurities removal. The tailings from the screen enter the high-intensity magnetic roughing process. The tailings from the high-intensity magnetic roughing process are then concentrated in a roughing thickener and then enter the scavenging screen for slag separation. The tailings from the scavenging screen enter the high-intensity magnetic scavenging process. The high-intensity magnetic roughing concentrate and the high-intensity magnetic scavenging concentrate are combined to form the hematite concentrate. The tailings from the roughing screen and scavenging screen are combined with the tailings from the scavenging screen to form the total tailings.

[0031] The production process for mixed hematite ore follows a magnetization-first, hematite-second selection process. The overflow from the hydrocyclone-controlled classification process first enters the magnetite production process (similar to the production process for standalone magnetite). After two rounds of separation (coarse and fine magnetite), magnetite concentrate is pre-selected. The tailings (i.e., hematite) from the coarse and fine magnetite are combined and then sent to the hematite production process for separation (similar to the production process for standalone hematite). The magnetite concentrate and hematite concentrate produced from the mixed hematite ore can be produced as separate concentrates or combined into a single mixed hematite concentrate.

[0032] S3: If Figure 2 As shown in the figure, when magnetite is produced alone, the grinding and classification operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 1# and 4# opening and closing points in the variable process and opening the 2# and 3# opening and closing points in the process to realize the independent production of magnetite. Specifically:

[0033] The hydrocyclone controls the overflow from the classification process, which is then sorted twice in the weak magnetic separator. The overflow from the hydrocyclone then flows through the 2# switch to the weak magnetic rougher for primary magnetite roughing. The rougher concentrate then flows through the weak magnetic concentrator for secondary concentrating, with the final magnetite concentrate being the concentrate. The tailings from the primary magnetite rougher and the secondary magnetite concentrator are combined and sent to the total tailings thickener through the 3# switch.

[0034] S4: As Figure 3 As shown in FIG. 1 , when producing hematite alone, the grinding and grading operations are the same as those in S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 2# and 3# opening and closing points in the variable process and opening the 1# and 4# opening and closing points to realize the single production process of hematite. Specifically:

[0035] The hydrocyclone controls the overflow from the classification process, which is then sorted twice by a high-intensity magnetic separator. The overflow then flows through the 1# and 4# switching points to the roughing screen for impurities removal. The tailings from the screen enter the high-intensity magnetic equipment for roughing hematite. The tailings from the high-intensity magnetic roughing are then concentrated in the roughing thickener and then enter the scavenging screen for slag separation. The tailings from the scavenging screen enter the high-intensity magnetic equipment for scavenging hematite. The high-intensity magnetic roughing concentrate and the high-intensity magnetic scavenging concentrate are combined to form the final hematite concentrate. The tailings from the roughing screen and scavenging screen are combined with the scavenging tailings and enter the total tailings thickener.

[0036] S5: If Figure 4As shown in the figure, during the production of mixed hematite ore, the grinding and classification operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 1# and 3# opening and closing points in the variable process and opening the 2# and 4# opening and closing points to realize the production process of mixed hematite ore with magnetic first and then red. Specifically:

[0037] The production process of magnetic hematite mixed ore is a separation process of magnetic first and then hematite. The magnetite concentrate is pre-selected by weak magnetic equipment, and then its tailings (i.e. hematite) are separated by strong magnetic equipment.

[0038] The hydrocyclone controls the grading overflow to enter the magnetite production process through the 2# opening and closing point, and then enters the magnetite weak magnetic roughing equipment for roughing. The roughed magnetite concentrate then enters the magnetite weak magnetic concentrator for concentrating. The concentrating concentrate is magnetite concentrate.

[0039] The weak magnetic rougher tailings (hematite) and weak magnetic concentrator tailings (hematite) are combined and passed through the #4 switch point to the rougher screen. The tailings below the screen enter the high-strength magnetic equipment for hematite roughing. The high-strength magnetic rougher tailings are thickened in the rougher tailings thickener and then enter the scavenger screen for slag separation. The tailings below the scavenger screen enter the high-strength magnetic equipment for scavenging of hematite. The high-strength magnetic rougher concentrate and the high-strength magnetic scavenger concentrate are combined to form the final hematite concentrate. The tailings above the rougher screen and scavenger screen are combined with the scavenger tailings and enter the total tailings thickener.

[0040] According to market demand, the magnetite concentrate and hematite concentrate produced from the hematite mixed ore can be two separate concentrate products, or they can be mixed into one hematite mixed concentrate product.

[0041] In summary: the present invention provides a variable grinding and separation process for magnetite and hematite, which uses a cyclone to control and classify the overflow of the original first-stage grinding inspection and classification, improves the classification accuracy, and makes the fineness of the overflow product after the first-stage grinding and classification operation meet the requirements of the separation conditions. Compared with the two-stage grinding and classification process, it reduces the number of grinding stages, simplifies the grinding process configuration, and avoids the shortcomings of the traditional controlled classification using a spiral classifier with a large classification area and low classification accuracy; secondly, the present invention realizes the needs of separate magnetite production, separate hematite production and mixed production of magnetic hematite through a variable process to obtain corresponding iron concentrate products, achieve flexible production group, and fully utilize the production capacity of the existing equipment of the ore dressing plant.

[0042] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A variable grinding separation process for magnetic and hematite, characterized by: The following steps are involved: S1: A closed-circuit grinding overflow-controlled classification operation is used: the raw ore is fed into the ball mill for grinding, then enters the spiral classifier for inspection and classification. The sand returned by the spiral classifier is returned to the ball mill for re-grinding. The overflow product of the spiral classifier enters the hydrocyclone for controlled classification. The sand is set in the hydrocyclone and returned to the ball mill for re-grinding. The overflow of the hydrocyclone enters the separation process. S2: The hydrocyclone controls the overflow of the classification to enter the variable process for sorting according to the different properties of the processed minerals. The variable process sorting operation is divided into three production processes: single magnetite production, single hematite production, and mixed hematite production. The three production processes are switched at the variable switching points according to the different properties of the raw ore. There are four variable switching points in the variable process, all of which are controlled by electric slurry valves. Each electric slurry valve has one opening and closing point, namely 1# opening and closing point, 2# opening and closing point, 3# opening and closing point, and 4# opening and closing point. S3: When producing magnetite alone, the grinding and grading operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 1# and 4# opening and closing points in the variable process and opening the 2# and 3# opening and closing points in the process to realize the independent production of magnetite. S4: When producing hematite alone, the grinding and grading operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 2# and 3# opening and closing points in the variable process and opening the 1# and 4# opening and closing points to realize the single production process of hematite. S5: When producing mixed hematite ore, the grinding and classification operations are the same as S1. The process switching is completed by opening and closing the electric slurry valve in the variable process, that is, closing the 1# and 3# opening and closing points in the variable process and opening the 2# and 4# opening and closing points to realize the production process of mixed hematite ore with magnetic first and hematite later; In S2, the 1# and 2# opening and closing points are set between the hydrocyclone in the variable process to control the overflow of the classification and enter the separation process, that is, at the front end of the separate hematite production process; the 3# and 4# opening and closing points are set between the separate magnetite production process in the variable process after the rough and concentrated tailings are merged and the separate hematite production process, that is, at the front end of the separate hematite production process; The production process of magnetite in S2 is as follows: hydrocyclone controls the overflow of classification to carry out two separations, the first is magnetite roughing, the second is roughing concentrate and then magnetite concentration, the concentrate is the final magnetite concentrate, the tailings of the first magnetite roughing and the tailings of the second magnetite concentration are combined into the total tailings; The production process of hematite in S2 is as follows: the overflow from the hydrocyclone is controlled to enter the roughing slag screen for impurities removal, the slag screen under the screen enters the strong magnetic roughing, the strong magnetic roughing tailings are concentrated by the roughing tailings thickener and then enter the scavenging slag screen for slag separation, the slag screen under the screen enters the strong magnetic scavenging, the strong magnetic roughing concentrate and the strong magnetic scavenging concentrate are combined into hematite concentrate, the roughing slag screen, the scavenging slag screen and the scavenging tailings are combined into the total tailings; The production process of the magnetic hematite mixed ore in S2 is a selection production process of magnetization first and hematite later: the hydrocyclone controls the classification overflow to first enter the magnetite production process, and after two selections of magnetite roughing and concentrating, the magnetite concentrate is pre-selected; the tailings of the magnetite roughing and concentrating, namely the hematite, are merged and entered into the hematite production process for selection; the magnetite concentrate and hematite concentrate produced by the magnetic hematite mixed ore can be two separate concentrate products, or mixed into one magnetic hematite mixed concentrate product.

2. A variable grinding separation process for magnetic and hematite according to claim 1, characterized in that: The closed-circuit grinding overflow control and grading equipment in S1 consists of a ball mill, a spiral classifier, and a hydrocyclone. The sand returned from the spiral classifier and the sand settling in the hydrocyclone are returned to the ball mill for regrinding, and the grinding products after grinding with the original ore are circulated into the inspection and control grading and control grading processes; the overflow from the spiral classifier inspection and grading is then controlled and graded by the hydrocyclone, and the overflow from the hydrocyclone is the final grinding and grading overflow product.

3. A variable grinding separation process for magnetic and hematite according to claim 1, characterized in that: The hydraulic overflow material controlled by the hydrocyclone in S2 is in the form of a flowable slurry and is transported through pipelines in a variable process.

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