A pre-selection and sulfur flotation process for high-sulfur magnetite ore

Abstract

This invention discloses a pre-selection and sulfur flotation process for high-sulfur magnetite ore, belonging to the field of iron ore beneficiation technology. It includes the following steps: 1. Crushing and screening the high-sulfur magnetite ore; 2. Performing a first-stage grinding and classification on the undersize product; 3. Performing sulfur flotation on the overflow product from the first-stage classification to obtain sulfur concentrate, and discharging the sulfur tailings for subsequent iron beneficiation operations. In this step, the flotation process employs two roughing, two cleaning, and one scavenging stages, with middlings being centrally returned to the closed-circuit flotation process. BK 608 and MK 306 are used as collector A and collector B in the flotation process, respectively. This invention can reduce reagent consumption during the flotation process while improving the effective sulfur grade of the sulfur concentrate.

Description

Technical Field

[0001] This invention belongs to the field of iron ore beneficiation technology, and more specifically, relates to a pre-selection and sulfur flotation process for high-sulfur magnetite ore. Background Technology

[0002] Pre-selection is a crucial step in iron ore beneficiation, and tailings disposal during pre-selection is an important means of achieving "more crushing, less grinding" and "early disposal of tailings that can be disposed of." For single magnetite ores, the application of pre-selection is becoming increasingly mature. However, for high-sulfur magnetite ores, there are still no successful and effective cases of pre-selection. This is mainly due to the difficulty in balancing tailings disposal yield and the magnetic iron content in the tailings. If more tailings are disposed of, the magnetic iron grade in the tailings will be high, affecting the overall magnetic iron recovery rate and iron concentrate yield. Conversely, if less tailings are disposed of to ensure the magnetic iron grade in the tailings, it is difficult to guarantee the magnetic iron grade of the ore fed into the mill, increasing the burden on subsequent grinding and beneficiation operations and thus affecting the quality of the iron concentrate.

[0003] Furthermore, for high-sulfur magnetite ore, to ensure that the sulfur content in the iron concentrate does not exceed the standard, a process of first flotation and then magnetization is often adopted. Currently, collectors and frothers are usually added for flotation sulfur removal, such as a one-roughing-two-cleaning-one-scavenging process, to obtain qualified sulfur concentrate products (effective sulfur grade greater than 40.0%) while reducing the effective sulfur content in the tailings to avoid affecting the quality of iron concentrate in subsequent iron beneficiation operations. However, this often results in high reagent consumption and high costs. In recent years, new types of collectors have emerged that do not require the addition of frothers, which can greatly reduce reagent consumption. However, these collectors also have drawbacks such as large fluctuations in indicators, the need to increase reagent dosage when the effective sulfur grade in the raw ore increases significantly, leading to flotation cell overflow and difficulty in production control. Summary of the Invention

[0004] 1. The problem to be solved

[0005] To address the problem of poor performance in existing pre-selection and sulfur flotation processes for high-sulfur magnetite ore, this invention provides a pre-selection and sulfur flotation process for high-sulfur magnetite ore that can reduce reagent consumption during flotation and improve the effective sulfur grade of sulfur concentrate.

[0006] 2. Technical Solution

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A pre-selection and sulfur flotation process for high-sulfur magnetite ore includes the following steps:

[0009] 1. Crush and screen the high-sulfur magnetite ore;

[0010] 2. The undersize product undergoes a first-stage grinding and classification process;

[0011] 3. The first stage overflow product is subjected to sulfur flotation to obtain sulfur concentrate, and the sulfur tailings are discharged to enter the subsequent iron beneficiation operation. In this step, the flotation process adopts two roughing, two cleaning and one scavenging. The middlings are returned to the closed flotation process. BK 608 and MK 306 are used as collector A and collector B in the flotation process, respectively.

[0012] As a further improvement to the technical solution, the specific process of step one is as follows: the high-sulfur magnetite ore is crushed from -250mm to -60mm, and then the crushed product is screened to obtain three particle sizes: +50mm, -50+10mm and -10mm.

[0013] As a further improvement to the technical solution, step one also includes: directly grinding the obtained -10mm particle size product into the ball mill ore bin; dry separating the obtained -50+10mm particle size product into coarse and scavenging tailings, retaining the dry separation tailings, and combining the dry separation concentrate with the obtained +50mm particle size for fine crushing and returning it to the screening equipment to form a closed circuit.

[0014] As a further improvement to the technical solution, the dry roughing separation adopts an LCT1014 permanent magnet dry large-block magnetic separator with a magnetic field strength of 0.3T; the dry sweeping separation adopts a CTX0820 dry magnetic separator with a magnetic field strength of 0.4T.

[0015] As a further improvement to the technical solution, the undersize product in step two refers to the -10mm particle size product obtained in step one, and the grinding particle size in this step is controlled to account for 50% to 55% of the -0.076mm particle size.

[0016] As a further improvement to the technical solution, in step three, the reagent dosage for the first roughing is: collector A is 40-60 g / t, and collector B is 20-40 g / t; the reagent dosage for the second roughing is: collector A is 20-40 g / t, and collector B is 10-30 g / t; and the reagent dosage for the first scavenging is: collector A is 10-30 g / t, and collector B is 5-15 g / t.

[0017] As a further improvement to the technical solution, the screening equipment in step one adopts a double-layer circular vibrating screen, with the upper screen hole size being 20×50mm and the lower screen hole size being 10×30mm.

[0018] As a further improvement to the technical solution, the grinding process in step two uses an MQY 4060 overflow ball mill.

[0019] As a further improvement to the technical solution, the grading in step two uses a Φ500×6 hydrocyclone group.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The present invention provides a pre-selection and sulfur flotation process for high-sulfur magnetite ore. The crushed product of high-sulfur magnetite ore is subjected to double-layer screening and classification. The -10mm particle size product is directly put into the ball mill ore bin to eliminate the influence of fine particles on the dry separation of large pieces. The +50mm particle size product is directly returned to the fine crushing and is not subjected to dry separation because its particle size is large and the useful minerals are not fully liberated. Entering the dry separation operation will easily lead to excessive loss of magnetic iron, effective sulfur and copper elements in the dry separation tailings. The -50+10mm particle size is subjected to dry separation to remove some of the large tailings. It can be sold as building aggregate and the amount of ore entering the fine crushing is reduced, which is conducive to reducing the load of the fine crushing cone crusher and achieving energy saving and efficiency improvement.

[0023] (2) The present invention provides a pre-selection and sulfur flotation process for high-sulfur magnetite ore. The dry selection adopts a roughing and scavenging process and uses different types of equipment. The dry roughing adopts the LCT1014 permanent magnet dry large block magnetic separator, and the dry scavenging adopts the CTX0820 dry magnetic separator, which is conducive to giving full play to the advantages of different types of dry selection equipment.

[0024] (3) The present invention provides a pre-selection and sulfur flotation process for high-sulfur magnetite ore. The sulfur flotation process adopts a closed-circuit flotation process with two roughing, two cleaning and one scavenging stages. The two roughing stages are beneficial to improving the roughing effect and increasing the recovery rate.

[0025] (4) The present invention provides a pre-selection and sulfur flotation process for high-sulfur magnetite ore. The flotation reagents use two different types of collectors in combination, which eliminates the need for frothers and gives full play to the synergistic effect between the two collectors, thereby reducing reagent consumption and reducing the production cost of the concentrator. Attached Figure Description

[0026] Figure 1 This is a process flow diagram of a pre-selection and sulfur flotation process for high-sulfur magnetite ore according to the present invention. Detailed Implementation

[0027] Exemplary embodiments of the present invention are described in detail below. While these exemplary embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be implemented and various changes may be made to the invention without departing from its spirit and scope. The more detailed description of embodiments of the invention below is not intended to limit the scope of the claimed invention, but is merely illustrative and does not limit the description of the features and characteristics of the invention, in order to suggest the best mode for carrying out the invention and to enable those skilled in the art to practice it. Therefore, the scope of the invention is defined only by the appended claims.

[0028] Example 1

[0029] like Figure 1 As shown, a pre-selection and sulfur flotation process for high-sulfur magnetite ore includes the following steps:

[0030] 1. The high-sulfur magnetite ore is crushed and screened, specifically as follows: the high-sulfur magnetite ore is crushed from -250mm to -60mm, and then the crushed product is screened to obtain three particle sizes: +50mm, -50+10mm, and -10mm. The -10mm particle size product is then directly fed into the ball mill grinding bin; the -50+10mm particle size product undergoes dry separation—coarsening and tailings removal—with the dry separation tailings retained. The dry separation concentrate and the obtained +50mm particle size are combined and finely crushed before being returned to the screening equipment to form a closed circuit.

[0031] In this embodiment, the dry roughing separation uses an LCT1014 permanent magnet dry large-block magnetic separator with a magnetic field strength of 0.3T; the dry scavenging separation uses a CTX0820 dry magnetic separator with a magnetic field strength of 0.4T. The screening equipment uses a double-layer circular vibrating screen, with the upper screen aperture size being 20×50mm and the lower screen aperture size being 10×30mm.

[0032] In this step, the crushed product of high-sulfur magnetite ore undergoes double-layer screening and classification. The -10mm particle size product is directly fed into the ball mill ore bin to eliminate the influence of fine particles on the dry separation of large pieces. The +50mm particle size product is directly returned to the fine crushing without dry separation because its particle size is large and the useful minerals are not fully liberated. Entering the dry separation operation would easily lead to excessive loss of magnetic iron, available sulfur and copper elements in the dry separation tailings. The -50mm and +10mm particle sizes are dry separated to remove some of the large tailings. This can be sold as building aggregate and the amount of ore entering the fine crushing is reduced, which helps to reduce the load on the fine crushing cone crusher and achieve energy saving and efficiency improvement.

[0033] The dry separation process employs a coarsening and scavenging step, utilizing different types of equipment. The coarsening stage uses an LCT1014 permanent magnet dry large-block magnetic separator, while the scavenging stage uses a CTX0820 dry magnetic separator, leveraging the advantages of each type of equipment. After implementing this method, the tailings rejection rate increased by 7.5 percentage points (from 8.5% to 16.0%, an increase of 88.24%), and the magnetic iron grade in the tailings decreased from 1.96% to 1.34% (a decrease of 31.63%). The significant increase in tailings yield coupled with a substantial reduction in magnetic iron grade far exceeded expectations (the expected target was to increase tailings yield without a significant increase or even a slight increase in magnetic iron grade), achieving unexpected technical benefits.

[0034] 2. Perform a first-stage grinding and classification on the undersize product. Specifically, the -10mm particle size product obtained in step one is subjected to a first-stage grinding and classification, and the first-stage classification overflow product is discharged. The grinding particle size is controlled so that the proportion of -0.076mm particle size is 50% to 55%.

[0035] In this embodiment, the grinding process uses an MQY 4060 overflow ball mill, and the grading process uses a Φ500×6 hydrocyclone assembly.

[0036] 3. The first stage overflow product is subjected to sulfur flotation to obtain sulfur concentrate, and the sulfur tailings are discharged to enter the subsequent iron beneficiation operation. In this step, the flotation process adopts two roughing, two cleaning and one scavenging. The middlings are returned to the closed flotation process. BK 608 and MK 306 are used as collector A and collector B in the flotation process, respectively.

[0037] In step three, the reagent dosage for the first roughing is: collector A is 40-60 g / t, and collector B is 20-40 g / t; the reagent dosage for the second roughing is: collector A is 20-40 g / t, and collector B is 10-30 g / t; the reagent dosage for the first scavenging is: collector A is 10-30 g / t, and collector B is 5-15 g / t.

[0038] Step three employs two roughing stages, which helps improve the roughing effect and increase the recovery rate. The flotation reagents use two types of collectors in combination, eliminating the need for a frother and leveraging the synergistic effect between the two collectors, thus reducing reagent consumption and lowering the production cost of the concentrator.

[0039] Before implementing this method, when collector A was used alone in combination with a frother for sulfur selection, with an effective sulfur grade of 5.67% in the feed ore and a total collector A dosage of 250 g / ton, the sulfur concentrate yield was 12.54%, the effective sulfur grade in the sulfur concentrate was 40.55%, and the effective sulfur recovery rate was 89.68%. With an effective sulfur grade of 5.96% in the feed ore and a total collector B dosage (without a frother) of 100 g / ton, the sulfur concentrate yield was 13.22%, the effective sulfur grade in the sulfur concentrate was 40.35%, and the effective sulfur recovery rate was 89.50%.

[0040] After implementing this method, using a mixture of collectors A and B for sulfur beneficiation, eliminating the need for frothers, and with an effective sulfur grade of 5.32% in the feed ore and a total dosage of collectors A and B of 160 g / ton, the sulfur concentrate yield was 11.29%, the effective sulfur grade in the concentrate was 41.77%, and the effective sulfur recovery rate was 88.64%. This demonstrates that the mixed use of the two collectors achieved a synergistic effect, significantly improving the beneficiation indicators. The effective sulfur grade in the concentrate increased by 1.22 percentage points, achieving an unexpected technical effect of 1+1>2. Simultaneously, it reduced reagent consumption per unit, which is beneficial for lowering the production costs of the beneficiation plant.

[0041] In summary, the pre-selection and sulfur flotation process for high-sulfur magnetite ore in this embodiment can reduce reagent consumption during the flotation process and improve the effective sulfur grade of the sulfur concentrate.

[0042] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A pre-selection and sulfur flotation process for high-sulfur magnetite ore, characterized in that: Includes the following steps:

1. Crush and screen the high-sulfur magnetite ore; 2. The undersize product undergoes a first-stage grinding and classification process; 3. The first stage overflow product is subjected to sulfur flotation to obtain sulfur concentrate, and the sulfur tailings are discharged to enter the subsequent iron beneficiation operation. In this step, the flotation process adopts two roughing, two cleaning and one scavenging. The middlings are returned to the closed flotation process. BK 608 and MK 306 are used as collector A and collector B in the flotation process, respectively. The specific process of step one is as follows: the high-sulfur magnetite ore is crushed from -250mm to -60mm, and then the crushed product is screened to obtain three particle sizes: +50mm, -50+10mm and -10mm. Step one further includes: directly grinding the obtained -10mm particle size product into the ball mill ore bin; dry separating the obtained -50+10mm particle size product into coarse and scavenging tailings, retaining the dry separation tailings, and combining the dry separation concentrate with the obtained +50mm particle size for fine crushing and returning it to the screening equipment to form a closed circuit.

2. The pre-selection and sulfur flotation process for high-sulfur magnetite ore according to claim 1, characterized in that: The dry roughing process uses an LCT1014 permanent magnet dry large-block magnetic separator with a magnetic field strength of 0.3T; the dry scavenging process uses a CTX0820 dry magnetic separator with a magnetic field strength of 0.4T.

3. The pre-selection and sulfur flotation process for high-sulfur magnetite ore according to claim 1, characterized in that: The undersize product in step two refers to the -10mm particle size product obtained in step one. In this step, the grinding particle size is controlled to have a proportion of -0.076mm particle size of 50% to 55%.

4. The pre-selection and sulfur flotation process for high-sulfur magnetite ore according to claim 1, characterized in that: In step three, the reagent dosage for the first roughing is: collector A is 40-60 g / t, and collector B is 20-40 g / t; the reagent dosage for the second roughing is: collector A is 20-40 g / t, and collector B is 10-30 g / t; the reagent dosage for the first scavenging is: collector A is 10-30 g / t, and collector B is 5-15 g / t.

5. The pre-selection and sulfur flotation process for high-sulfur magnetite ore according to any one of claims 1-4, characterized in that: In step one, the screening equipment uses a double-layer circular vibrating screen with an upper screen aperture size of 20×50mm and a lower screen aperture size of 10×30mm.

6. A pre-selection and sulfur flotation process for high-sulfur magnetite ore according to any one of claims 1-4, characterized in that: In step two, the grinding process uses an MQY 4060 overflow ball mill.

7. The pre-selection and sulfur flotation process for high-sulfur magnetite ore according to any one of claims 1-4, characterized in that: In step two, the grading process uses a Φ500×6 hydrocyclone assembly.

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