Novel Anshan type iron ore beneficiation process

Abstract

The invention discloses a novel mineral processing technology for Anshan type iron ore. The method comprises the specific steps that raw ore is subjected to a three-section two-closed-circuit crushing and screening process, and then qualified materials are obtained; after powder is subjected to wet-type pre-concentration, concentrate enters a grinding machine to be subjected to ore grinding operation, materials discharged by the grinding machine are subjected to weak magnetic roughing, and tailings can be thrown early. And the concentrate is graded through a hydrocyclone set and a high-frequency screen to form closed-loop grinding, qualified materials enter two sections of weak magnetic concentration and electromagnetic elutriation, final concentrate is obtained through filtering, magnetic tailings of all the sections are combined for tailings recovery, and the final tailings are subjected to dry discharging operation to obtain tailings and tail mud products. The combined beneficiation process of crushing, screening, large block dry separation, secondary screening, high-pressure roller grinding, wet-type pre-separation, grading, ore grinding, low-intensity magnetic separation, concentration, filtering and the like is adopted, qualified iron ore concentrate can be obtained, and magnetic tails of all sections can be used as building raw materials such as cement or gravel aggregate. The process is simplified, the milling grade is improved, the system production capacity is improved, the beneficiation cost is reduced, and the economic benefit of a beneficiation plant is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of ore dressing, and in particular relates to a new Anshan-type iron ore dressing process. Background Art

[0002] China's iron ore resources are widely distributed but relatively concentrated, with complete deposit types, more poor ores than rich ores, complex ore types, many associated (symbiotic) beneficial components, and great difficulty in comprehensive utilization. Among them, Anshan-type iron ore is the most widely distributed and the most important iron ore deposit in my country, accounting for about 48% of the total iron ore reserves. Because the deposit reserves, the size and thickness of a single ore body are large, and the burial depth is not deep, many deposits can be mined in the open pit. In addition, the ore type is mainly magnetite, and the distribution of the deposits is relatively concentrated, so this type of iron ore deposit has a great advantage in development and utilization.

[0003] The mineral composition of Anshan iron ore is simple, with magnetite as the main metal mineral, and a small amount of hematite and pyrite. The gangue mineral is mainly quartz, with a small amount of biotite, amphibole and calcite. The surrounding rock is biotite plagioclase amphibole gneiss, with a clear boundary between the ore body and the surrounding rock, belonging to medium hardness rock with good rock stability. The embedded particle size of magnetite is relatively fine, and the content of grinding to -0.074mm accounts for about 80%. The magnetic separation index is good after stage grinding and stage selection.

[0004] In the field of beneficiation of medium and low-grade iron ores such as magnetite, the process of step grinding and step selection is widely used. The purpose of this process is to discard tailings as much as possible, only grind concentrate, save energy and reduce consumption, and reduce the beneficiation cost of iron concentrate. However, in recent years, my country has developed and successfully applied new high-efficiency crushing and grinding equipment and sorting equipment. Therefore, compared with the replacement of beneficiation equipment, the traditional step grinding and step selection process still has shortcomings, with problems such as coarse inlet particle size, large mill selection, high power consumption, and increased beneficiation cost. Summary of the invention

[0005] In view of this, the purpose of the present invention is to improve the deficiencies in the traditional step-milling and step-dressing process and provide a new Anshan-type iron ore dressing process that can improve the dressing efficiency and reduce the dressing cost.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a new Anshan-type iron ore dressing process, which is characterized by comprising the following steps:

[0008] S1: Crushing, screening, and large-block dry separation: The raw ore is subjected to coarse and medium crushing. The crushed material is screened, and the material on the screen is returned to the medium crushing operation. The material under the screen is subjected to a coarse and sweep large-block dry separation operation. The coarse and sweep concentrates are combined and then enter the transfer silo. The sweep tailings enter the waste rock area.

[0009] S2: Secondary screening and fine crushing: Dry-select the coarse concentrate for secondary screening, the screened materials are finely crushed, the finely crushed materials are returned to the secondary screening operation, and the screened materials enter the powder bin.

[0010] S3: Wet pre-selection: The dry rough concentrate is subjected to wet pre-selection to obtain pre-selected concentrate and pre-selected tailings.

[0011] S4: Grinding, weak magnetic roughing and classification: The pre-selected concentrate is ground, the materials after grinding are subjected to weak magnetic roughing, the magnetic concentrate obtained is subjected to classification, the underflow of the first classification is returned to the grinding operation, the overflow of the first classification is subjected to secondary classification, and the materials on the screen are returned to the wet pre-selection operation.

[0012] S5: Weak magnetic concentration: The secondary classified underscreen materials are subjected to weak magnetic concentration to obtain the final concentrate and magnetically separated tailings.

[0013] S6: Tailings recovery: After the tailings from each magnetic separation stage are combined, tailings recovery operations are carried out to obtain recovered concentrate and final tailings. The recovered concentrate is returned to the wet pre-selection operation.

[0014] S7: Concentrate concentration and dehydration: The final concentrate is filtered and dehydrated to obtain the concentrate product and transport it to the concentrate yard.

[0015] S8: Tailings concentration and dehydration operation: The tailings are finally concentrated, and the bottom flow of the concentration is dehydrated. The material above the screen is the tailings sand product and is transported to the tailings yard, and the material under the screen is returned to the concentration operation; the overflow generated by the concentration is then subjected to a secondary concentration operation, and the bottom flow of the secondary concentration is subjected to a filter press dehydration operation to obtain the tailings mud product and transport it to the tailings yard.

[0016] S9: Sedimentation and clarification operations: The operating water obtained from the concentration and filtration of each product can be returned to each operating section for recycling after sedimentation and clarification, thus achieving the goal of zero discharge of mineral processing water.

[0017] As a preferred technical solution, in step S1, the raw ore is coarsely crushed by a jaw crusher, the coarsely crushed material is medium-crushed by a cone crusher, the medium-crushed material is screened by a circular vibrating screen, the screening of the circular vibrating screen is set to 40mm, and the qualified material under the screen is subjected to a one-coarse and one-sweep bulk dry separation operation by a permanent magnetic dry bulk magnetic separator, and the magnetic field strength is set to 6000Gs.

[0018] As a preferred technical solution, in step S2, the dry-selected coarse concentrate is screened twice using a relaxation screen, the relaxation screen is set to 3 mm, and the material above the screen + 3 mm is crushed using a high-pressure roller mill.

[0019] As a preferred technical solution, in step S3, the -3 mm dry-selected rough concentrate is wet-preselected using a permanent magnetic wet preselector, and the magnetic field strength is set to 6000 Gs.

[0020] As a preferred technical solution, in step S4, the wet pre-selected concentrate is ground using a ball mill, the ground material is subjected to weak magnetic roughing using a permanent magnetic drum magnetic separator, the magnetic field strength is set to 6000 Gs, the weak magnetic roughing concentrate is subjected to primary classification using a hydrocyclone group, and the overflow of the hydrocyclone is subjected to secondary classification using a high-frequency fine screen.

[0021] As a preferred technical solution, in step S5, the material under the high-frequency fine screen is subjected to weak magnetic separation using a double-drum permanent magnetic drum magnetic separator + an electromagnetic elutriator. The magnetic field strength of the permanent magnetic drum magnetic separator is set to 2000+1500Gs, and the fineness is about 75% to 80% of -200 mesh.

[0022] As a preferred technical solution, in step S6, the tailings from each section of magnetic separation are combined and then a waterless unloading recovery machine is used to recover the tailings, and the magnetic field strength is set to 1800 Gs.

[0023] As a preferred technical solution, in step S7, the final concentrate is filtered and dehydrated using a disc vacuum filter.

[0024] As a preferred technical solution, in step S8, the final tailings are concentrated using a hydrocyclone group, the underflow is dewatered using a dewatering screen, the overflow is secondary concentrated using a thickener, and the underflow of the thickener is filtered and dewatered using a plate and frame filter press tailings.

[0025] The beneficial effects of the present invention are as follows:

[0026] The dry-selected coarse concentrate is screened twice using a relaxation screen (3mm), the 3mm+ material on the screen is crushed by a high-pressure roller mill, and the crushed material is returned to the relaxation screen for secondary screening. This can effectively simplify the crushing process, increase crushing and reduce grinding, reduce the particle size entering the mill, and reduce energy consumption, thus achieving the goal of reducing the cost of mineral processing.

[0027] By using a permanent magnetic wet pre-separator to perform wet pre-separation on the -3mm dry-separated rough concentrate, some impurities and gangue minerals can be discarded in advance, the grade entering the mill can be increased, the system production capacity can be increased, and the purpose of improving the ore dressing efficiency can be achieved.

[0028] By using a ball mill to grind the pre-selected concentrate, using a permanent magnetic drum magnetic separator to perform weak magnetic roughing selection on the ground materials, using a hydrocyclone group to classify the obtained magnetic concentrate, the underflow is returned to the ball mill for grinding, the overflow is subjected to secondary classification using a high-frequency fine screen, and the screened material is returned to the wet pre-selection for concentration and then into the ball mill for grinding. This can remove some impurities and gangue minerals, reduce the iron ore grinding circulation volume, improve the system production capacity, and achieve the purpose of improving mineral processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of an embodiment of a new Anshan type iron ore beneficiation process of the present invention. DETAILED DESCRIPTION

[0030] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0031] Please refer to Figure 1 , which is an embodiment of a new Anshan type iron ore beneficiation process of the present invention, comprises the following steps:

[0032] S1: Crushing, screening, and large-block dry separation: The raw ore is subjected to coarse and medium crushing. The crushed material is screened, and the material on the screen is returned to the medium crushing operation. The material under the screen is subjected to a coarse and sweep large-block dry separation operation. The coarse and sweep concentrates are combined and then enter the transfer silo. The sweep tailings enter the waste rock area.

[0033] S2: Secondary screening and fine crushing: Dry-select the coarse concentrate for secondary screening, the screened materials are finely crushed, the finely crushed materials are returned to the secondary screening operation, and the screened materials enter the powder bin.

[0034] S3: Wet pre-selection: The dry rough concentrate is subjected to wet pre-selection to obtain pre-selected concentrate and pre-selected tailings.

[0035] S4: Grinding, weak magnetic roughing and classification: The pre-selected concentrate is ground, the materials after grinding are subjected to weak magnetic roughing, the magnetic concentrate obtained is subjected to classification, the underflow of the first classification is returned to the grinding operation, the overflow of the first classification is subjected to secondary classification, and the materials on the screen are returned to the wet pre-selection operation.

[0036] S5: Weak magnetic concentration: The secondary classified underscreen materials are subjected to weak magnetic concentration to obtain the final concentrate and magnetically separated tailings.

[0037] S6: Tailings recovery: After the tailings from each magnetic separation stage are combined, tailings recovery operations are carried out to obtain recovered concentrate and final tailings. The recovered concentrate is returned to the wet pre-selection operation.

[0038] S7: Concentrate concentration and dehydration: The final concentrate is filtered and dehydrated to obtain the concentrate product and transport it to the concentrate yard.

[0039] S8: Tailings concentration and dehydration operation: The tailings are finally concentrated, and the bottom flow of the concentration is dehydrated. The material above the screen is the tailings sand product and is transported to the tailings yard, and the material under the screen is returned to the concentration operation; the overflow generated by the concentration is then subjected to a secondary concentration operation, and the bottom flow of the secondary concentration is subjected to a filter press dehydration operation to obtain the tailings mud product and transport it to the tailings yard.

[0040] S9: Sedimentation and clarification operations: The operating water obtained from the concentration and filtration of each product can be returned to each operating section for recycling after sedimentation and clarification, thus achieving the goal of zero discharge of mineral processing water.

[0041] In this embodiment, the raw ore is coarsely crushed by a jaw crusher, the coarsely crushed material is medium crushed by a cone crusher, the medium crushed material is screened by a circular vibrating screen, the screening of the circular vibrating screen is set to 40mm, and the qualified materials under the screen are subjected to a coarse and sweep bulk dry separation operation by a permanent magnetic dry bulk magnetic separator, and the magnetic field strength is set to 6000Gs.

[0042] In this embodiment, the dry-selected coarse concentrate is screened twice using a relaxation screen, the relaxation screen is set to 3 mm, and the material above the screen + 3 mm is crushed using a high-pressure roller mill.

[0043] In this embodiment, -3 mm dry-selected coarse concentrate is wet pre-selected using a permanent magnetic wet pre-selector, and the magnetic field strength is set to 6000 Gs.

[0044] In this embodiment, the wet pre-selected concentrate is ground by a ball mill, the ground material is subjected to weak magnetic roughing by a permanent magnetic drum magnetic separator, the magnetic field strength is set to 6000 Gs, the weak magnetic roughing concentrate is subjected to primary classification by a hydrocyclone group, and the overflow of the hydrocyclone is subjected to secondary classification by a high-frequency fine screen.

[0045] In this embodiment, the material under the high-frequency fine screen is screened using a double-drum permanent magnetic drum magnetic separator + an electromagnetic elutriator for weak magnetic separation. The magnetic field strength of the permanent magnetic drum magnetic separator is set to 2000+1500Gs, and the fineness is about 75% to 80% of -200 mesh.

[0046] In this embodiment, the tailings from each stage of magnetic separation are combined and then a waterless unloading recovery machine is used to recover the tailings, and the magnetic field strength is set to 1800 Gs.

[0047] In this embodiment, the final concentrate is filtered and dehydrated using a disc vacuum filter.

[0048] In this embodiment, the final tailings are concentrated using a hydrocyclone group, the underflow is dewatered using a dewatering screen, the overflow is secondary concentrated using a thickener, and the underflow of the thickener is filtered and dewatered using a plate and frame filter press tailings.

[0049] Taking an iron ore concentrator in a certain area of ​​Chaoyang, Liaoning as an example, the specific implementation mode of the present invention is further described:

[0050] The iron ore mined locally is Anshan-type iron ore. The original ore is gray or bright gray, with medium-grained and medium-fine-grained metamorphic structure and banded structure. The minerals are mainly magnetite and quartz. The magnetite in the ore is often arranged in continuous or discontinuous bands and quartz alternately. The ore minerals are mainly magnetite, containing a small amount of hematite and pyrite. The gangue minerals are mainly quartz, followed by amphibole and feldspar. The ore grade is low, and the industrial type is poor iron ore. The ore grade is low, and the average grade of the deposit is about TFe20%.

[0051] The raw ore (≤800mm) is crushed by coarse and medium crushing before entering the circular vibrating screen (40mm) for screening. The material with a size of +40mm on the screen returns to the medium crushing to form a closed circuit. The material with a size of -40mm under the screen is subjected to two large dry selection processes, one coarse and one sweeping, and then is discarded. The coarse and fine materials are mixed and then enter the relaxation screen (3mm) for screening. The material with a size of +3mm on the screen enters the high-pressure roller mill for fine crushing. The discharged material enters the relaxation screen for screening, and the material with a size of -3mm under the screen enters the powder silo. After that, it is fed into wet pre-selection (6000Gs), the pre-selected concentrate enters the ball mill for grinding, the mill discharge enters weak magnetic roughing (3000Gs), the concentrate is pumped into the hydrocyclone group for classification, the underflow returns to the mill for grinding, the overflow enters the high-frequency screen for classification, the screen returns to the wet pre-selection concentration and then enters the ball mill for grinding, the screen enters two-stage weak magnetic selection (2000+1500Gs), the concentrate is then selected by electromagnetic washing, and the concentrate is filtered to obtain the final concentrate product. The tailings of each stage of magnetic separation are combined and then recycled. The recovered concentrate returns to the wet pre-selection and concentration and then enters the ball mill for grinding. The recovered tailings are concentrated and dehydrated by the cyclone + dewatering screen to obtain the tailings product. The overflow of the tailings cyclone flows into the thickener for concentration, and then the tailings product is obtained by filter pressure.

[0052] After the iron ore is subjected to the process of the present invention, as shown in Table 1, the yield of magnetite concentrate is 12.69%, the TFe grade is 67.13%, and the TFe recovery rate is 42.07%; the yield of bulk tailings is 31.53%, the TFe grade is 9.61%, and the MFe grade is 0.62%; the yield of tailings is

[0053] Table 1. Anshan iron ore dressing index

[0054]

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A new Anshan iron ore dressing process, characterized in that: The following steps are involved: S1: Crushing, screening, and large-block dry separation: The raw ore is subjected to coarse and medium crushing. The crushed material is screened, and the material on the screen is returned to the medium crushing operation. The material under the screen is subjected to a coarse and sweep large-block dry separation operation. The coarse and sweep concentrates are combined and then enter the transfer silo. The sweep tailings enter the waste rock area. S2: Secondary screening and fine crushing: Dry-select the coarse concentrate for secondary screening, the screened materials are finely crushed, the finely crushed materials are returned to the secondary screening operation, and the screened materials enter the powder bin. S3: Wet pre-selection: The dry rough concentrate is subjected to wet pre-selection to obtain pre-selected concentrate and pre-selected tailings. S4: Grinding, weak magnetic roughing and classification: The pre-selected concentrate is ground, the materials after grinding are subjected to weak magnetic roughing, the magnetic concentrate obtained is subjected to classification, the underflow of the first classification is returned to the grinding operation, the overflow of the first classification is subjected to secondary classification, and the materials on the screen are returned to the wet pre-selection operation. S5: Weak magnetic concentration: The secondary classified underscreen materials are subjected to weak magnetic concentration to obtain the final concentrate and magnetically separated tailings. S6: Tailings recovery: After the tailings from each magnetic separation stage are combined, tailings recovery operations are carried out to obtain recovered concentrate and final tailings. The recovered concentrate is returned to the wet pre-selection operation. S7: Concentrate concentration and dehydration: The final concentrate is filtered and dehydrated to obtain the concentrate product and transport it to the concentrate yard. S8: Tailings concentration and dehydration operation: The tailings are finally concentrated, and the bottom flow of the concentration is dehydrated. The material above the screen is the tailings sand product and is transported to the tailings yard, and the material under the screen is returned to the concentration operation; the overflow generated by the concentration is then subjected to a secondary concentration operation, and the bottom flow of the secondary concentration is subjected to a filter press dehydration operation to obtain the tailings mud product and transport it to the tailings yard. S9: Sedimentation and clarification operations: The operating water obtained from the concentration and filtration of each product can be returned to each operating section for recycling after sedimentation and clarification, thus achieving the goal of zero discharge of mineral processing water.

2. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S1, the raw ore is coarsely crushed by a jaw crusher, the coarsely crushed material is medium-crushed by a cone crusher, the medium-crushed material is screened by a circular vibrating screen, the screening of the circular vibrating screen is set to 40mm, and the qualified material under the screen is subjected to a one-coarse and one-sweep bulk dry separation by a permanent magnetic dry bulk magnetic separator, and the magnetic field strength is set to 6000Gs.

3. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S2, the dry-selected coarse concentrate is screened twice using a relaxation screen, the relaxation screen is set to 3 mm, and the material above the screen + 3 mm is crushed using a high-pressure roller mill.

4. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S3, the -3 mm dry-selected rough concentrate is wet pre-selected using a permanent magnetic wet pre-selector, and the magnetic field strength is set to 6000 Gs.

5. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S4, the wet pre-selected concentrate is ground using a ball mill, and the ground material is subjected to weak magnetic roughing using a permanent magnetic drum magnetic separator, with the magnetic field strength set to 6000 Gs. The weak magnetic roughing concentrate is subjected to primary classification using a hydrocyclone group, and the overflow of the hydrocyclone is subjected to secondary classification using a high-frequency fine screen.

6. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S5, the material screened under the high-frequency fine screen is subjected to weak magnetic separation using a double-drum permanent magnetic drum magnetic separator + an electromagnetic elutriator, and the magnetic field strength of the permanent magnetic drum magnetic separator is set to 2000+1500Gs.

7. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S6, the tailings from each stage of magnetic separation are combined and then recovered by a waterless unloading recovery machine, with the magnetic field strength set to 1800 Gs.

8. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S7, the final concentrate is filtered and dehydrated using a disc vacuum filter.

9. A new Anshan iron ore dressing process according to claim 1, characterized in that: In step S8, the final tailings are concentrated using a hydrocyclone group, the underflow is dewatered using a dewatering screen, the overflow is secondary concentrated using a thickener, and the underflow of the thickener is filtered and dewatered using a plate and frame filter press tailings.

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