Beneficiation method for grading treatment of refractory iron oxide ore

Abstract

The invention discloses a grading treatment beneficiation method for refractory iron oxide ore, which comprises the following steps of: carrying out grinding grading, strong magnetic roughing and cyclone grading on fine crushed ore (less than or equal to 12mm) to separate into relatively easily separated materials (roughing concentrate and scavenging concentrate) and refractory materials (cyclone overflow) by adopting grading treatment, wherein the grade of strong magnetic tailings is less than or equal to 10 percent; the materials easy to select are finely ground to-400-mesh materials, the content of the materials is 85-95%, and then cation reverse flotation is conducted through a (C8 + C10 ether amine collecting agent, and the process of one rough process, one fine process and four sweeping processes is conducted); and after being dehydrated, the refractory materials are subjected to fluidized roasting (the temperature of a main furnace is 850-1050 DEG C / the temperature of a reduction furnace is 500-650 DEG C), weak magnetic concentration and demagnetization, and finally the refractory materials are combined with the easy-to-separate materials for reverse flotation. According to the process, only refractory materials accounting for 15-20% of raw ore are roasted, and compared with a whole roasting process, the investment is reduced by 60%, the energy consumption is reduced by 70%, the metal recovery rate reaches 88.5%, and the concentrate cost is reduced by 15%.

Description

Technical Field

[0001] The present invention belongs to the technical field of processing of refractory oxidized iron ores, and particularly relates to a beneficiation method for separating and treating refractory oxidized iron ores according to their qualities. Background Art

[0002] The traditional beneficiation process for oxidized iron ores adopts the combination of high-intensity magnetic separation + fine grinding + reverse flotation, but it has poor effects on refractory ores with fine dissemination size and complex mineral composition (such as the Jingtieshan Iron Ore of Jiuquan Steel). Due to the uneven dissemination size of minerals in this ore, the current beneficiation process is as follows: Lump ore: shaft furnace magnetization roasting → low-intensity magnetic separation → reverse flotation (the large roasting particle size leads to insufficient reduction and low metal recovery rate); Powder ore: high-intensity magnetic separation (serious loss of fine-grained metals and low recovery rate).

[0003] Although the improved all-suspension magnetization roasting process can improve the concentrate grade and recovery rate, it has the defects of large investment, high energy consumption, and high carbon emissions. In contrast, high-intensity magnetic separation - cationic reverse flotation has low cost and low carbon emissions, but has low recovery rate due to the loss of fine and ultrafine-grained metals, and poor foam fluidity. Although fluidized bed roasting magnetic separation can efficiently process fine-grained materials, its high-cost problem has not been solved. Therefore, there is an urgent need to develop an innovative process that combines cost advantages and recovery rate advantages. Summary of the Invention

[0004] The purpose of the present invention is to provide a beneficiation process for separating and treating refractory oxidized iron ores according to their qualities, so as to solve the contradiction that the existing processes cannot have both high recovery rate and low cost / low energy consumption.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: 1. A beneficiation method for separating and treating refractory oxidized iron ores according to their qualities, characterized by comprising the combination of the following three parts of processes: (1) The process of separating and treating according to qualities, which sequentially includes the following steps: S1: Perform a first-stage grinding and classification operation on the refractory oxidized iron ores with a particle size ≤ 12 mm after fine crushing. The discharge of the ball mill is fed into a hydrocyclone for classification. The overflow of the hydrocyclone is fed into a high-frequency fine screen for screening. The screening particle size is 0.15 - 0.6 mm. The hydrocyclone underflow and the oversize products are returned to the ball mill for re-grinding. The content of -200 mesh in the undersize products accounts for 50% - 70%; S2: Perform medium-intensity magnetic separation and high-intensity magnetic separation on the undersize products obtained from the grinding and classification in S1 in sequence. The magnetic field intensity of the medium-intensity magnetic separation is 300 - 450 mT, and the magnetic field intensity of the high-intensity magnetic separation is 0.6 - 1.1 T. The concentrates of the medium-intensity magnetic separation and the high-intensity magnetic separation are combined to obtain the rough concentrate. The tailings of the medium-intensity magnetic separation are fed into the high-intensity magnetic separation to produce the rough tailings; S3: Classify the roughly selected tailings obtained in S2 using a hydrocyclone to obtain hydrocyclone underflow and hydrocyclone overflow. The content of -200 mesh in the hydrocyclone underflow is 30% - 45%, and the content of -400 mesh in the hydrocyclone overflow is ≥80%; S4: Add water to the hydrocyclone underflow obtained in S3 to adjust the pulp concentration to 30 - 45%, and perform scavenging using a high-intensity magnetic separator. The scavenging magnetic field intensity is 0.8 - 1.3 T to obtain scavenging concentrate and scavenging tailings; (2) Processing technology for easy-to-separate materials, including the following steps in sequence: S5: Combine the roughly selected concentrate obtained in S2 and the scavenging concentrate obtained in S4 as easy-to-separate materials, and perform two-stage grinding and classification operations. After hydrocyclone classification, the underflow is fed into a vertical stirring mill for grinding, and the mill discharge is fed into a hydrocyclone for further classification. The fineness of the overflow product obtained is 90% - 95% of -300 mesh content to -400 mesh content; S6: After concentrating the overflow product obtained from the grinding and classification in S5 to a pulp concentration of 30 - 35%, perform cationic reverse flotation operations according to the following steps: a) First drug addition and stirring: Add a pH adjuster: sodium hydroxide or sulfuric acid to adjust the pulp pH value to 7 - 9, and at the same time add an inhibitor: corn starch 300 - 1500 g / t; b) Second drug addition and stirring: Add a collector: C8 + C10 ether amine acetate 40 - 120 g / t; c) Adopt a flotation process of 1 roughing, 1 cleaning, and 4 scavengings. Among them: The roughing concentrate enters the cleaning operation; The cleaning foam returns to the roughing operation; The roughing foam product enters the first scavenging; The scavenging foams of each time enter the next-level scavenging in sequence; Except that the first scavenging concentrate returns to the concentration operation before flotation, the remaining scavenging concentrates (middlings) return to the previous-level scavenging operation in sequence; Finally, obtain flotation concentrate and flotation tailings; (3)Processing technology for difficult-to-separate materials, including the following steps in sequence: S7: Use the hydrocyclone overflow obtained in S3 as difficult-to-separate materials, and concentrate and filter-press to dehydrate to a moisture content of 10% - 12%; S8: Perform fluidized magnetization roasting treatment on the filter cake obtained in S7, and perform drying, dispersing, preheating, heating, reduction, and cooling in sequence. Among them, heating, reduction, and cooling are completed in different reactors, Heating is completed in the main furnace, and the temperature is 850 - 1050 °C; Reduction is completed in the reduction furnace, and the temperature is 500 - 650 °C; The reducing gas is CO + H2, and the content is 15% - 35%; Cool it in a waste heat boiler under nitrogen protection to below 200°C, and then make pulp in water; S9: For the pulp with a concentration of 30% - 40% after making pulp in S8, use a weak magnetic separator for 2 - 4 times of cleaning to obtain weak magnetic concentrate and weak magnetic tailings; S10: After demagnetizing the weak magnetic concentrate obtained in S9, merge it with the flotation feed of S6, and carry out cationic reverse flotation according to the same drug addition system and process as in S6; Final product: The flotation concentrate of S6 is the total concentrate, and the scavenging tailings of S4, the flotation tailings of S6 and the weak magnetic tailings of S9 are merged into the total tailings.

[0006] Furthermore, the screening particle size of the high-frequency fine screen in S1 is 0.15 - 0.6 mm.

[0007] Furthermore, before the cleaning in S6, add a collector: 20 - 60 g / t of C8 + C10 ether amine acetate. The inhibitor in S6: The addition amount of corn starch is 300 - 600 g / t.

[0008] Furthermore, the temperature of the reduction furnace in S8 is 530 - 600°C; the cooling is under nitrogen protection. [[ID= / / ID=17]]

[0009] Furthermore, the scavenging concentrate obtained in S4 can be selected to be merged with the hydrocyclone overflow obtained in S3 as difficult-to-separate materials according to the ore properties and process requirements. At this time: This merged material enters steps S7, S8, S9, and S10 for treatment; In step S9, it is necessary to carry out closed-circuit grinding and classification on the weak magnetic concentrate obtained by the first weak magnetic separation, and grind it to a product fineness of 90% - 95% of -300 mesh content and -400 mesh content; The weak magnetic tailings obtained in S9 are merged into the total tailings.

[0010] The present invention has the following beneficial effects: The present invention first uses the combination of steps S1, S2, S3, and S4 to perform beneficiation treatment on refractory oxidized iron ore, separating the raw ore into relatively easy-to-beneficiate rough concentrate, scavenging concentrate (the two are combined and called relatively easy-to-beneficiate materials), and hydrocyclone overflow with fine particle size and difficult beneficiation (called difficult-to-beneficiate materials), creating conditions for giving full play to the advantages of the two processes in the follow-up. Since the strong magnetic scavenging in S4 only removes qualified tailings from the hydrocyclone underflow, and all of the hydrocyclone overflow is treated by the fluidized roasting magnetic separation process, the problem of metal loss in the fine particle size fraction is effectively avoided, and the disadvantages of the original strong magnetic separation + reverse flotation process are overcome; the difficult-to-beneficiate materials are treated by the fluidized roasting magnetic separation + cationic reverse flotation process, giving full play to the advantages of the fluidized roasting magnetic separation, greatly improving the metal recovery rate of the fine particle size fraction. After weak magnetic separation of the roasted ore, the fine particle size slime is removed, creating conditions for improving the reverse flotation efficiency and reducing reagent consumption. Compared with the full roasting process, the metal recovery rate is increased by 2.68 percentage points. Since the materials entering the fluidized roasting only account for about 15 - 20% of the raw ore (if the strong magnetic scavenging concentrate is incorporated into the difficult-to-beneficiate materials, the difficult-to-beneficiate materials entering the roasting account for 30 - 35% of the raw ore), compared with the full roasting process, the investment of the present invention is reduced by 60%, the concentrate cost after deducting the roasting loss is reduced by 15.6%, the energy consumption is reduced by 70%, and the carbon emission is reduced by 52.8%. Since the roasting amount is greatly reduced, the roasting loss of the concentrate increases by 16.7 percentage points. Although the concentrate grade drops by 11.91 percentage points, the concentrate grade after deducting the roasting loss only drops by 1.91 percentage points. The specific data are shown in Table 1 below: Table 1 Comparison of Process Effects Brief Description of the Drawings

[0011] Figure 1 It is a schematic flow diagram of the first implementation mode of the process of the present invention.

[0012] Figure 2 It is a schematic flow diagram of the second implementation mode of the process of the present invention. Detailed Implementation Modes

[0013] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0014] Example 1 As Figure 1 shown, this example processes the refractory oxidized iron ore of Jiuquan Iron and Steel's Jingtieshan, including the following steps: 1. Beneficiation treatment process S1 Grinding and classification: Process the raw ore with a particle size ≤ 10 mm. The discharge of the first-stage ball mill is classified by a hydrocyclone (working pressure 0.15 MPa); The overflow of the hydrocyclone is fed into a high-frequency fine screen (screening particle size 0.30 mm), and the content of -200 mesh in the undersize product is 60%; The hydrocyclone underflow and the oversize product are returned to the ball mill; S2 Strong magnetic roughing: Removing strongly magnetic minerals (medium magnetic field drum magnetic separator, magnetic field intensity 400 mT); Separating with a flat ring high-intensity magnetic separator (magnetic field intensity 0.85 T) to obtain roughing concentrate (grade 45%) and roughing tailings (grade 18%); S3 Tailings classification: The roughing tailings are classified by a hydrocyclone (pressure 0.12 MPa) to obtain underflow (-200 mesh content 38%) and overflow (-400 mesh content 92%); S4 Strong magnetic scavenging: The underflow is adjusted to a concentration of 38% and scavenged by a vertical ring high-gradient magnetic separator (magnetic field intensity 1.0 T), and the grade of the scavenging tailings is 9.5%; 2. Treatment of relatively easy-to-separate materials S5 Grinding and classification: The roughing concentrate and the scavenging concentrate are combined and ground in a vertical stirring mill; the fineness of the hydrocyclone overflow is -400 mesh content 90% (working pressure 0.15 MPa) S6 Cationic reverse flotation: The pulp concentration is 32%, and H2SO4 is added to adjust the pH value of the pulp from 10.0 to 8.5; The inhibitor is corn starch at 800 g / t, and the collector is C8 + C10 ether amine acetate at 70 g / t; Flotation process: 1 roughing, 1 cleaning, and 4 scavenging. After deducting the burning loss, the concentrate grade is 60.5% and the recovery rate is 88.5%; 3. Treatment of difficult-to-separate materials S7 Dewatering: The hydrocyclone overflow is concentrated and filtered (filter cake moisture 11%); S8 Fluidized bed roasting: The main furnace temperature is 950 °C, and the reduction furnace temperature is 580 °C; The content of the reducing gas CO + H2 is 35%, and it is cooled to 180 °C under nitrogen protection; S9 Weak magnetic separation: The pulp concentration is adjusted to 35%, and after 4 times of cleaning, weak magnetic concentrate (grade 53.8%) is obtained; S10 Combined reverse flotation: After demagnetizing the weak magnetic concentrate, it is combined with the feed of S6. After deducting the burning loss, the concentrate grade is 60.5% and the recovery rate is 88.5%; Combined tailings: S4 scavenging tailings + S6 flotation tailings + S9 weak magnetic tailings (total tailings grade 10.6%).

[0015] Example 2 As shown Figure 2 in the figure, the present embodiment processes the refractory oxidized iron ore of Jiuquan Iron and Steel's Jingtieshan Mine, including the following steps: 1. Medium-separated treatment process S1 Grinding and classification: Process the raw ore with a particle size of ≤10 mm after fine crushing; The discharge of the first-stage ball mill is fed into a hydrocyclone group for classification (working pressure 0.18 MPa); The overflow of the hydrocyclone is classified by a high-frequency fine screen (screen aperture 0.30 mm), and the content of the product below -200 mesh is 60%; The hydrocyclone underflow and the over-screen product are returned to the ball mill for re-grinding; S2 High-intensity magnetic roughing: Remove strongly magnetic minerals (medium-magnetic drum magnetic separator, magnetic field intensity in the scavenging area 450 mT); Separate with a flat-ring high-intensity magnetic separator (magnetic field intensity 0.85 T) to obtain roughing concentrate (grade 46.0%) and roughing tailings (grade 24.0%); S3 Tailings classification: The roughing tailings are classified by a hydrocyclone (pressure 0.15 MPa) to obtain underflow (-200 mesh content 42%) and overflow (-400 mesh content 93%); S4 High-intensity magnetic scavenging: The underflow is adjusted to a concentration of 40%, Scavenge with a vertical-ring high-gradient high-intensity magnetic separator (magnetic field intensity 1.15 T); Key adjustment: The scavenging concentrate is incorporated into the refractory materials (accounting for 35% of the total raw ore), and the grade of the scavenging tailings is 9.6%; 2. Treatment of relatively easy-to-process materials S5 Grinding and classification: Only use the high-intensity magnetic roughing concentrate of S2 as the relatively easy-to-process materials, grind with a vertical stirring mill (grinding concentration 65%), and perform hydrocyclone closed-circuit classification (working pressure 0.18 MPa), with the overflow fineness of -400 mesh content 88%; S6 Cationic reverse flotation: The concentrated pulp concentration is 33%, Drug addition process: The first stirring: Add sulfuric acid to adjust the pH to 8.3, and at the same time add 550 g / t of corn starch; The second stirring: Add 65 g / t of C8 + C10 ether amine acetate; Supplement 30 g / t of collector before cleaning; Flotation process: 1 roughing, 1 cleaning, and 4 scavenging; After deducting the burning loss, the concentrate grade is 61.0%, and the grade of the flotation tailings is 20.3%; 3. Deep treatment of refractory materials S7 Dewatering: Merge the overflow of the S3 cyclone and the concentrate of the S4 scavenging (total solids content accounts for 30% of the original ore); Concentrate to a concentration of 58% and pressure filter (pressure in the pressure chamber is 0.38 MPa); The moisture content of the filter cake is 10.5%; S8 Fluidized Bed Roasting: Feed the filter cake into the suspended magnetization roasting system; Drying section: 250 - 300 °C; Main heating furnace: 980 °C (bottom temperature of the furnace); Reduction furnace: 580 °C (CO + H2 content is 32%); Cool to 180 °C under nitrogen protection; S9 Grinding - Weak Magnetic Concentration: The pulp concentration of the roasted ore is 32%; Weak magnetic roughing (magnetic field intensity is 0.25 T); The rough concentrate is finely ground by a vertical agitation mill (the content of -400 mesh in the cyclone overflow is 85%); 4 - stage weak magnetic concentration (the magnetic field intensity decreases by 0.05 T successively); Obtain weak magnetic concentrate (grade is 53.5%), and the grade of the tailings is 9.8%; S10 Combined Reverse Flotation: After demagnetizing the weak magnetic concentrate, it is combined with the product of S5 grinding, Carry out cationic reverse flotation under the same conditions as S6, Finally, the grade of the roasted and burned concentrate is 61.0% after deducting the burning loss, and the grade of the comprehensive tailings is 10.6%; Tailings System: Total tailings = Tailings of S4 scavenging + Tailings of S6 flotation + Tailings of S9 weak magnetism, The comprehensive grade of the tailings is 10.6%, and the metal recovery rate is 89.2%.

[0016] Effect Comparison: Table 2 Product Comparison of Examples 1 - 2

Claims

1. A beneficiation method for the separate treatment of refractory oxidized iron ore, characterized in that, It includes the combination of the following three parts of processes: (1) The separate treatment process, which sequentially includes the following steps: S1: Conduct a first-stage grinding and classification operation on the refractory oxidized iron ore with a particle size ≤ 12 mm after fine crushing. The discharge of the ball mill is fed into a hydrocyclone for classification, and the overflow of the hydrocyclone is fed into a high-frequency fine screen for screening. The screening particle size is 0.15 - 0.6 mm. The sand deposit of the hydrocyclone and the oversize products are returned to the ball mill for re-grinding. The content of -200 mesh in the undersize products is 50% - 70%; S2: Conduct medium-intensity magnetic separation and high-intensity magnetic separation on the undersize products obtained from the grinding and classification in S1 in sequence. The magnetic field intensity of the medium-intensity magnetic separation is 300 - 450 mT, and the magnetic field intensity of the high-intensity magnetic separation is 0.6 - 1.1 T. The concentrates of the medium-intensity magnetic separation and the high-intensity magnetic separation are combined to obtain the rough concentrate, and the tailings of the medium-intensity magnetic separation are fed into the high-intensity magnetic separation to produce the rough tailings; S3: Use a hydrocyclone to classify the rough tailings obtained in S2 to obtain the sand deposit of the hydrocyclone and the overflow of the hydrocyclone. The content of -200 mesh in the sand deposit of the hydrocyclone is 30% - 45%, and the content of -400 mesh in the overflow of the hydrocyclone is ≥ 80%; S4: Add water to the sand deposit of the hydrocyclone obtained in S3 to adjust the pulp concentration to 30 - 45%, and conduct scavenging using a high-intensity magnetic separator. The magnetic field intensity of the scavenging is 0.8 - 1.3 T to obtain the scavenging concentrate and the scavenging tailings; (2) The treatment process for easy-to-separate materials, which sequentially includes the following steps: S5: Combine the rough concentrate obtained in S2 and the scavenging concentrate obtained in S4 into easy-to-separate materials and conduct a second-stage grinding and classification operation. After the hydrocyclone classification, the sand deposit is fed into a vertical agitated mill for grinding, and the discharge of the mill is fed into the hydrocyclone for continuous classification. The fineness of the obtained overflow product is 90% of -300 mesh content to 95% of -400 mesh content; S6: After concentrating the overflow product obtained from the grinding and classification in S5 to a pulp concentration of 30 - 35%, conduct a cationic reverse flotation operation according to the following steps: a) First drug addition and stirring: Add a pH adjuster: sodium hydroxide or sulfuric acid to adjust the pH value of the pulp to 7 - 9, and at the same time add an inhibitor: corn starch 300 - 1500 g / t; b) Second drug addition and stirring: Add a collector: C8 + C10 ether amine acetate 40 - 120 g / t; c) Adopt a flotation process of 1 roughing, 1 cleaning, and 4 scavengings, where: The roughing concentrate enters the cleaning operation; The cleaning foam returns to the roughing operation; The roughing foam products enter the first scavenging; The foams of each scavenging enter the next-level scavenging in sequence; Except for the first scavenging concentrate returning to the concentration operation before flotation, the other scavenging concentrates return to the previous-level scavenging operation in sequence; Finally, obtain the flotation concentrate and the flotation tailings; (3) The treatment process for refractory materials, which sequentially includes the following steps: S7: Use the overflow of the hydrocyclone obtained in S3 as refractory materials, and conduct concentration and pressure filtration dehydration to a moisture content of 10% - 12%; S8: Conduct fluidized magnetization roasting treatment on the filter cake obtained in S7, and conduct drying, breaking up, preheating, heating, reduction, and cooling in sequence. Among them, heating, reduction, and cooling are completed in different reactors, Heating is completed in the main furnace, with a temperature of 850 - 1050 °C; Reduction is completed in the reduction furnace, with a temperature of 500 - 650 °C; The reducing gas is CO + H2, with a content of 15% - 35%; Cool it in a waste heat boiler under nitrogen protection to below 200°C, and then make pulp in water; S9: For the pulp with a concentration of 30% - 40% after pulping in S8, use a weak magnetic separator for 2 - 4 times of cleaning to obtain weak magnetic concentrate and weak magnetic tailings; S10: After demagnetizing the weak magnetic concentrate obtained in S9, merge it with the flotation feed of S6, and carry out cationic reverse flotation according to the same drug addition system and process as in S6; Final product: The flotation concentrate of S6 is the total concentrate, and the scavenging tailings of S4, the flotation tailings of S6 and the weak magnetic tailings of S9 are merged into the total tailings.

2. The beneficiation method for separating and treating refractory oxidized iron ore according to claim 1, wherein: The reduction furnace temperature of S8 is 530 - 600°C.

3. A beneficiation method for separating and treating refractory oxidized iron ore according to claim 1, characterized in that: The cooling of S8 is carried out under nitrogen protection.

4. A beneficiation method for separating and treating refractory oxidized iron ore according to claim 1, characterized in that: Before the cleaning in S6, add a collector: 20 - 60 g / t of C8 + C10 ether amine acetate.

5. A beneficiation method for separating and treating refractory oxidized iron ore according to claim 1, characterized in that: The inhibitor of S6: The addition amount of corn starch is 300 - 600 g / t.

6. A beneficiation method for the separated treatment of refractory oxidized iron ore according to claim 1, characterized in that: The screening particle size of the high-frequency fine screen in S1 is 0.2 - 0.4 mm.

7. A beneficiation method for separating and treating refractory oxidized iron ore according to claim 1, characterized in that: The scavenging concentrate obtained in S4 can be selected to be merged with the hydrocyclone overflow obtained in S3 as refractory materials according to the ore properties and process requirements. At this time: This merged material enters steps S7, S8, S9, and S10 for treatment; In step S9, it is necessary to grind and classify the weak magnetic concentrate obtained by one-time weak magnetic separation, and grind it to a product fineness of 90% -300 mesh content to 95% -400 mesh content; The weak magnetic tailings obtained in S9 are merged into the total tailings.

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