A production method for extracting iron concentrate from industrial iron-containing tailings

Abstract

The present application relates to the technical field of mineral processing, in particular to a production method for extracting iron concentrate from industrial iron-containing tailings. The method comprises the following steps: screening and removing impurities from the industrial iron-containing tailings raw material to remove large stone blocks, impurities and caked materials in the tailings, and performing coarse crushing and fine crushing to obtain tailings powder with a classification overflow particle size of 200 mesh accounting for 65-85%; adding the tailings powder into a soaking tank, adding water and a dispersing agent, and then soaking and cleaning to obtain cleaned ore slurry; adding a composite activation additive to the cleaned ore slurry, stirring uniformly, and then performing low-temperature magnetization activation to obtain activated ore slurry; performing one-stage magnetic separation and two-stage magnetic separation on the activated ore slurry to obtain two-stage magnetic separation concentrate; sending the two-stage magnetic separation concentrate into a flotation machine after slurry preparation to perform reverse flotation desilication, adding an inhibitor and a collector, and then performing one-time roughing, one-time scavenging and twice concentration to obtain flotation concentrate; and performing dehydration and drying on the flotation concentrate to obtain iron concentrate product. By using the method, the grade of the final product iron concentrate can reach more than 65%, and the iron recovery rate can reach more than 80%.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically a production method for extracting iron concentrate from industrial iron-bearing tailings. Background Technology

[0002] Iron ore mining, beneficiation, steel smelting, and non-ferrous metal smelting processes generate large quantities of industrial iron-bearing tailings. These tailings are mostly stored in tailings ponds, occupying significant amounts of agricultural and forestry land. Furthermore, the maintenance and repair of these tailings ponds require substantial funds, leading to continuously increasing tailings dam heights and growing safety hazards. In addition, existing industrial iron-bearing tailings still contain large amounts of fine-grained magnetite, hematite, and limonite, with iron grades generally ranging from 10% to 35%, possessing extremely high recycling value.

[0003] Currently, traditional iron extraction processes from tailings mostly employ a single ball milling and magnetic separation process, which has significant technical drawbacks: First, the iron minerals in the tailings are finely embedded and closely coexist with gangue, making it difficult for conventional grinding to achieve sufficient liberation, resulting in low iron recovery rates; second, the tailings contain a high proportion of weakly magnetic iron minerals, which cannot be effectively captured by conventional magnetic separation, leading to the loss of a large amount of valuable iron components with the tailings; third, the tailings contain high levels of impurities such as silica, alumina, and calcium and magnesium salts, which cannot be deeply removed by single physical beneficiation, resulting in low-grade iron concentrate with excessive impurities that cannot meet the standards of the iron and steel smelting industry; fourth, traditional processes have high energy consumption and low resource utilization rates, and wastewater and waste residue cannot be recycled, resulting in high production costs and hindering the large-scale resource utilization of industrial iron-bearing tailings. Summary of the Invention

[0004] In view of this, the present invention provides a production method for extracting iron concentrate from industrial iron-bearing tailings, aiming to solve the technical problems in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for extracting iron concentrate from industrial iron-bearing tailings includes the following steps: Step S1: Screen and remove impurities from industrial iron-containing tailings raw materials to remove large stones, debris and agglomerated materials from the tailings. Perform coarse and fine crushing to make the graded overflow particle size of -200 mesh account for 65%-85% of the tailings powder. Step S2: Add the tailings powder to the soaking tank, add water and dispersant, and then soak and wash. The dispersant is sodium hexametaphosphate or water glass, and the amount added is 0.05%-0.15% of the material mass. The soaking time is 2-6 hours, and the washing temperature is controlled at 40-60℃ to obtain the washed slurry. Step S3: Add the cleaned slurry to the composite activation aid, stir evenly, and then perform low-temperature magnetization activation to obtain activated slurry; Step S4: The activated slurry is subjected to a first-stage magnetic separation and a second-stage magnetic separation to obtain a second-stage magnetic separation concentrate; Step S5: After adjusting the pulp of the two-stage magnetic separation concentrate, send it to the flotation machine for reverse flotation desilication. The flotation pH value is 8-10. Add inhibitors and collectors. After one roughing, one scavenging and two cleaning processes, flotation concentrate is obtained. Step S6: Dehydrate and dry the flotation concentrate to obtain iron concentrate product.

[0006] A further improvement of the present invention is that, in step S2, the weight ratio of tailings powder to water is 1:(1.5-3), and the amount of dispersant added is 0.05%-0.15% of the weight of tailings powder.

[0007] A further improvement of the present invention is that, in step S3, the amount of the composite activating agent added is 0.8%-1.5% of the weight of the tailings powder.

[0008] A further improvement of the present invention is that, in step S3, the composite activating agent is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of (5-7):(2-3):1.

[0009] A further improvement of the present invention is that, in step S3, the activation temperature is 55-75℃, the stirring speed is 300-400 r / min, and the activation time is 15-25 min.

[0010] A further improvement of the present invention is that, in step S4, the slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation, with a magnetic field strength of 3000-5000 Gs, to obtain a first-stage magnetic concentrate.

[0011] A further improvement of the present invention is that, in step S4, the first-stage magnetic concentrate is fed into a weak magnetic separator for second-stage magnetic separation, with a magnetic field strength of 800-1500 Gs, and the magnetic field strength of the second-stage magnetic separation is less than 1 / 3 of that of the first-stage magnetic separation, thereby obtaining a second-stage magnetic concentrate.

[0012] A further improvement of the present invention is that, in step S5, the slurry is adjusted to a mass concentration of 25%-35%, the pH of the slurry is adjusted to 8.5-9.5 with sodium carbonate, stirred for 3-5 minutes, and then an anionic collector equivalent to 0.1%-0.25% of the tailings powder mass is added, stirred for 2-3 minutes, and then reverse flotation desilication is carried out.

[0013] A further improvement of the present invention is that, in step S5, the inhibitor is starch; and the collector is an anionic collector selected from at least one of sodium oleate, sodium stearate, sodium linoleate, oxidized paraffin soap, tal oil, benzoyl hydroxamic acid, and salicylic acid.

[0014] A further improvement of the present invention is that, in step S5, the following steps are used to perform one coarse selection, one sweep selection, and two fine selections: Step S501, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 5-8 minutes, and 50-70% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S502, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining collector is added, aeration and stirring are carried out for 3-5 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S503, First Cleaning: The underflow from the roughing stage enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 4-6 minutes; the foam from the first cleaning stage is returned to the roughing stage, and the underflow from the first cleaning stage enters the second cleaning stage; Step S504, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 3-5 minutes; the froth from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate, which enters the next process.

[0015] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows: The present invention provides a production method for extracting iron concentrate from industrial iron-bearing tailings. By adding a composite activating agent composed of calcium oxide, calcium fluoride and sodium carbonate, the slurry is activated at a low temperature of 55-75℃. This enhances the surface activity and significantly increases the magnetic susceptibility of weakly magnetic iron minerals such as hematite and limonite, thereby enabling them to be effectively recovered in subsequent magnetic separation.

[0016] In addition, before magnetization, the dispersant cleaning removes residual reagents and sludge from the surface of the tailings particles, providing a clean mineral surface for low-temperature magnetization activation, allowing the composite activation aid to act more effectively on the iron mineral surface; and the activation treatment further improves the surface properties and magnetic susceptibility of the iron mineral, creating favorable conditions for subsequent magnetic separation and flotation.

[0017] Furthermore, there is a significant synergistic relationship between the various steps of this invention. Crushing and grinding provide suitable particle size for each process, dispersant cleans and purifies the mineral surface, low-temperature activation enhances the selectivity of weakly magnetic iron minerals, gradient magnetic separation achieves efficient enrichment, and reverse flotation ensures the final quality. Using the method of this invention, the final product iron concentrate grade can reach more than 65%, and the iron recovery rate can reach more than 80%. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Example 1

[0019] The industrial iron-bearing tailings used in this embodiment are tailings from a magnetite beneficiation process, with a total iron grade of 18.5% and quartz as the main gangue mineral.

[0020] Step S1, Crushing and Grinding: The industrial iron-bearing tailings raw material is screened and impurities are removed to remove large stones, debris and agglomerated materials from the tailings. Coarse crushing and fine crushing are carried out to make the tailings powder with a graded overflow particle size of -200 mesh account for 75%.

[0021] Step S2, Chemical Pretreatment Immersion Cleaning: The tailings powder is added to an immersion tank, and clean water is added at a water-to-material mass ratio of 2:1. Sodium hexametaphosphate dispersant is added at a mass of 0.10% of the tailings powder. The immersion time is 4 hours, and the cleaning temperature is controlled at 50℃ to obtain a cleaned slurry.

[0022] Step S3, Low-temperature magnetization activation: Add a composite activation aid to the cleaned slurry. The composite activation aid is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of 6:2.5:1, and the amount added is 1.2% of the mass of the tailings powder. Activate the slurry by stirring at 350 r / min for 20 min at 65℃ to obtain the activated slurry.

[0023] Step S4, Magnetic Separation: The activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 4000 Gs to obtain a first-stage magnetic concentrate; the first-stage magnetic concentrate is fed into a weak magnetic separator for a second-stage magnetic separation with a magnetic field strength of 900 Gs to obtain a second-stage magnetic concentrate.

[0024] Step S5, Reverse Flotation Purification: Adjust the pulp of the two-stage magnetic separation concentrate to a pulp concentration of 30%, adjust the pulp pH to 9.0 with sodium carbonate, add the inhibitor starch (0.2% of dry mineral weight), and stir for 4 minutes; then add the collector sodium oleate (0.18% of dry mineral weight), and stir for 2.5 minutes; then perform reverse flotation desilication: Step S501, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 5 minutes, and 50% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S502, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining 40% of the collector is added, aerated and stirred for 4 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S503, First Cleaning: The roughing underflow enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 5 minutes; the foam from the first cleaning is returned to the roughing operation, and the underflow from the first cleaning enters the second cleaning operation; Step S504, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 4 minutes; the foam from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate.

[0025] Step S6, Dehydration and Drying: The flotation concentrate is dehydrated and dried to obtain iron concentrate product.

[0026] Testing showed that the iron concentrate obtained in this embodiment had a total iron content of 66.5% and an iron recovery rate of 82.3%. Example 2

[0027] The industrial iron-bearing tailings used in this embodiment are flotation tailings of copper smelting slag, with a total iron grade of 22.3%.

[0028] Step S1, Crushing and Grinding: The industrial iron-bearing tailings raw material is screened and impurities are removed to remove large stones, debris and agglomerated materials from the tailings. Coarse crushing and fine crushing are carried out to make the tailings powder with a graded overflow particle size of -200 mesh account for 80%.

[0029] Step S2, Chemical Pretreatment Immersion Cleaning: The tailings powder is added to the immersion tank, and clean water is added at a ratio of 1.5:1 (water to material mass ratio). Sodium hexametaphosphate dispersant is added at a rate of 0.08% of the tailings powder mass. The immersion time is 3 hours, and the cleaning temperature is controlled at 45℃ to obtain a cleaned slurry.

[0030] Step S3, Low-temperature magnetization activation: Add a composite activation aid to the cleaned slurry. The composite activation aid is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of 7:2:1, and the amount added is 1.4% of the mass of the tailings powder. Activate the slurry by stirring at 400 r / min for 15 min at 60℃ to obtain the activated slurry.

[0031] Step S4, Magnetic Separation: The activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 3500 Gs to obtain a first-stage magnetic concentrate; the first-stage magnetic concentrate is fed into a weak magnetic separator for a second-stage magnetic separation with a magnetic field strength of 850 Gs to obtain a second-stage magnetic concentrate.

[0032] Step S5, Reverse Flotation Purification: Adjust the pulp of the two-stage magnetic separation concentrate to a pulp concentration of 30%, adjust the pulp pH to 9.0 with sodium carbonate, add water glass inhibitor (0.2% of dry mineral mass), and stir for 4 minutes; then add sodium oleate collector (0.18% of dry mineral mass), and stir for 2.5 minutes; then perform reverse flotation desilication: Step S501, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 6 minutes, and 60% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S502, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining 40% of the collector is added, aerated and stirred for 4 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S503, First Cleaning: The roughing underflow enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 5 minutes; the foam from the first cleaning is returned to the roughing operation, and the underflow from the first cleaning enters the second cleaning operation; Step S504, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 4 minutes; the foam from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate.

[0033] Step S6, Dehydration and Drying: The flotation concentrate is dehydrated and dried to obtain iron concentrate product.

[0034] Testing showed that the total iron content of the iron concentrate obtained in this embodiment was 66.2%, and the iron recovery rate was 80.1%. Example 3

[0035] The industrial iron-bearing tailings used in this embodiment are flotation tailings of copper smelting slag, with a total iron grade of 22.3%.

[0036] Step S1, Crushing and Grinding: The industrial iron-bearing tailings raw material is screened and impurities are removed to remove large stones, debris and agglomerated materials from the tailings. Coarse crushing and fine crushing are carried out to make the tailings powder with a graded overflow particle size of -200 mesh account for 80%.

[0037] Step S2, Chemical Pretreatment Immersion Cleaning: The tailings powder is added to the immersion tank, and clean water is added at a ratio of 3:1 (water to material mass). Sodium hexametaphosphate dispersant is added at a rate of 0.08% of the tailings powder mass. The immersion time is 3 hours, and the cleaning temperature is controlled at 45℃ to obtain a cleaned slurry.

[0038] Step S3, Low-temperature magnetization activation: Add a composite activation aid to the cleaned slurry. The composite activation aid is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of 5:3:1, and the amount added is 1.4% of the mass of the tailings powder. Activate the slurry by stirring at 300 r / min for 25 min at 60℃ to obtain the activated slurry.

[0039] Step S4, Magnetic Separation: The activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 3500 Gs to obtain a first-stage magnetic concentrate; the first-stage magnetic concentrate is fed into a weak magnetic separator for a second-stage magnetic separation with a magnetic field strength of 850 Gs to obtain a second-stage magnetic concentrate.

[0040] Step S5, Reverse Flotation Purification: Adjust the pulp of the two-stage magnetic separation concentrate to a pulp concentration of 30%, adjust the pulp pH to 9.0 with sodium carbonate, add the inhibitor starch (0.2% of dry mineral weight), and stir for 4 minutes; then add the collector sodium oleate (0.18% of dry mineral weight), and stir for 3 minutes; then perform reverse flotation desilication: Step S501, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 8 minutes, and 60% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S502, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining 40% of the collector is added, aerated and stirred for 4 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S503, First Cleaning: The roughing underflow enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 5 minutes; the foam from the first cleaning is returned to the roughing operation, and the underflow from the first cleaning enters the second cleaning operation; Step S504, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 4 minutes; the foam from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate.

[0041] Step S6, Dehydration and Drying: The flotation concentrate is dehydrated and dried to obtain iron concentrate product.

[0042] Testing showed that the total iron content of the iron concentrate obtained in this embodiment was 66.3%, and the iron recovery rate was 80.5%.

[0043] Comparative Example 1 The industrial iron-bearing tailings used in this embodiment are flotation tailings of copper smelting slag, with a total iron grade of 22.3%.

[0044] Step S1, Crushing and Grinding: The industrial iron-bearing tailings raw material is screened and impurities are removed to remove large stones, debris and agglomerated materials from the tailings. Coarse crushing and fine crushing are carried out to make the tailings powder with a graded overflow particle size of -200 mesh account for 80%.

[0045] Step S2, Chemical Pretreatment Immersion Cleaning: The tailings powder is added to the immersion tank, and clean water is added at a ratio of 1.5:1 (water to material mass ratio). Sodium hexametaphosphate dispersant is added at a rate of 0.08% of the tailings powder mass. The immersion time is 3 hours, and the cleaning temperature is controlled at 45℃ to obtain a cleaned slurry.

[0046] Step S3, Magnetic Separation: The activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 3500 Gs to obtain a first-stage magnetic concentrate; the first-stage magnetic concentrate is fed into a weak magnetic separator for a second-stage magnetic separation with a magnetic field strength of 850 Gs to obtain a second-stage magnetic concentrate.

[0047] Step S4, Reverse Flotation Purification: Adjust the pulp of the two-stage magnetic separation concentrate to a pulp concentration of 30%, adjust the pulp pH to 9.0 with sodium carbonate, add the inhibitor starch (0.2% of dry mineral weight), and stir for 4 minutes; then add the collector sodium oleate (0.18% of dry mineral weight), and stir for 2.5 minutes; then perform reverse flotation desilication: Step S401, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 6 minutes, and 60% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S402, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining 40% of the collector is added, aerated and stirred for 4 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S403, First Cleaning: The underflow from the roughing stage enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 5 minutes; the foam from the first cleaning stage is returned to the roughing stage, and the underflow from the first cleaning stage enters the second cleaning stage; Step S404, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 4 minutes; the foam from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate.

[0048] Step S5, Dehydration and Drying: The flotation concentrate is dehydrated and dried to obtain iron concentrate product.

[0049] The iron concentrate obtained in this comparative example has a total iron content of 62.5% and an iron recovery rate of 71.8%.

[0050] Comparative Example 2 The industrial iron-bearing tailings used in this embodiment are flotation tailings of copper smelting slag, with a total iron grade of 22.3%.

[0051] Step S1, Crushing and Grinding: The industrial iron-bearing tailings raw material is screened and impurities are removed to remove large stones, debris and agglomerated materials from the tailings. Coarse crushing and fine crushing are carried out to make the tailings powder with a graded overflow particle size of -200 mesh account for 80%.

[0052] Step S2, Chemical Pretreatment Immersion Cleaning: The tailings powder is added to the immersion tank, and clean water is added at a ratio of 1.5:1 (water to material mass ratio). Sodium hexametaphosphate dispersant is added at a rate of 0.08% of the tailings powder mass. The immersion time is 3 hours, and the cleaning temperature is controlled at 45℃ to obtain a cleaned slurry.

[0053] Step S3, Low-temperature magnetization activation: Add a composite activation aid to the cleaned slurry. The composite activation aid is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of 1:1:1, and the amount added is 1.4% of the mass of the tailings powder. Activate the slurry by stirring at 400 r / min for 15 min at 60℃ to obtain the activated slurry.

[0054] Step S4, Magnetic Separation: The activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 3500 Gs to obtain a first-stage magnetic concentrate; the first-stage magnetic concentrate is fed into a weak magnetic separator for a second-stage magnetic separation with a magnetic field strength of 850 Gs to obtain a second-stage magnetic concentrate.

[0055] Step S5, Reverse Flotation Purification: Adjust the pulp of the two-stage magnetic separation concentrate to a pulp concentration of 30%, adjust the pulp pH to 9.0 with sodium carbonate, add the inhibitor starch (0.2% of dry mineral weight), and stir for 4 minutes; then add the collector sodium oleate (0.18% of dry mineral weight), and stir for 2.5 minutes; then perform reverse flotation desilication: Step S501, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 6 minutes, and 60% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S502, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining 40% of the collector is added, aerated and stirred for 4 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S503, First Cleaning: The roughing underflow enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 5 minutes; the foam from the first cleaning is returned to the roughing operation, and the underflow from the first cleaning enters the second cleaning operation; Step S504, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 4 minutes; the foam from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate.

[0056] Step S6, Dehydration and Drying: The flotation concentrate is dehydrated and dried to obtain iron concentrate product.

[0057] Testing showed that the total iron content of the iron concentrate obtained in this embodiment was 66.2%, and the iron recovery rate was 80.1%.

[0058] The iron concentrate obtained in this comparative example has a total iron content of 63.2% and an iron recovery rate of 74.5%.

[0059] Comparative Example 3 The industrial iron-bearing tailings used in this embodiment are flotation tailings of copper smelting slag, with a total iron grade of 22.3%.

[0060] Step S1, Crushing and Grinding: The industrial iron-bearing tailings raw material is screened and impurities are removed to remove large stones, debris and agglomerated materials from the tailings. Coarse crushing and fine crushing are carried out to make the tailings powder with a graded overflow particle size of -200 mesh account for 80%.

[0061] Step S2, Low-temperature magnetization activation: After adding water to the tailings powder, add a composite activation aid, which is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of 7:2:1, and the amount added is 1.4% of the mass of the tailings powder; activate at 60℃ and 400r / min for 15min to obtain activated slurry.

[0062] Step S3, Magnetic Separation: The activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 3500 Gs to obtain a first-stage magnetic concentrate; the first-stage magnetic concentrate is fed into a weak magnetic separator for a second-stage magnetic separation with a magnetic field strength of 850 Gs to obtain a second-stage magnetic concentrate.

[0063] Step S4, Reverse Flotation Purification: Adjust the pulp of the two-stage magnetic separation concentrate to a pulp concentration of 30%, adjust the pulp pH to 9.0 with sodium carbonate, add the inhibitor starch (0.2% of dry mineral weight), and stir for 4 minutes; then add the collector sodium oleate (0.18% of dry mineral weight), and stir for 2.5 minutes; then perform reverse flotation desilication: Step S401, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 6 minutes, and 60% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S402, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining 40% of the collector is added, aerated and stirred for 4 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S403, First Cleaning: The underflow from the roughing stage enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 5 minutes; the foam from the first cleaning stage is returned to the roughing stage, and the underflow from the first cleaning stage enters the second cleaning stage; Step S404, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 4 minutes; the foam from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate.

[0064] Step S5, Dehydration and Drying: The flotation concentrate is dehydrated and dried to obtain iron concentrate product.

[0065] The iron concentrate obtained in this comparative example has a total iron content of 63.8% and an iron recovery rate of 73.2%.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for extracting iron concentrate from industrial iron-bearing tailings, characterized in that, Includes the following steps: Step S1: Screen and remove impurities from industrial iron-containing tailings raw materials to remove large stones, debris and agglomerated materials from the tailings. Perform coarse and fine crushing to make the graded overflow particle size of -200 mesh account for 65%-85% of the tailings powder. Step S2: Add the tailings powder to the soaking tank, add water and dispersant, and then soak and wash. The dispersant is sodium hexametaphosphate or water glass, and the amount added is 0.05%-0.15% of the material mass. The soaking time is 2-6 hours, and the washing temperature is controlled at 40-60℃ to obtain the washed slurry. Step S3: Add the cleaned slurry to the composite activation aid, stir evenly, and then perform low-temperature magnetization activation to obtain activated slurry; Step S4: The activated slurry is subjected to a first-stage magnetic separation and a second-stage magnetic separation to obtain a second-stage magnetic separation concentrate; Step S5: After adjusting the pulp of the two-stage magnetic separation concentrate, send it to the flotation machine for reverse flotation desilication. The flotation pH value is 8-10. Add inhibitors and collectors. After one roughing, one scavenging and two cleaning processes, flotation concentrate is obtained. Step S6: Dehydrate and dry the flotation concentrate to obtain iron concentrate product.

2. The production method for extracting iron concentrate from industrial iron-bearing tailings according to claim 1, characterized in that, In step S2, the weight ratio of tailings powder to water is 1:(1.5-3), and the amount of dispersant added is 0.05%-0.15% of the weight of tailings powder.

3. The production method for extracting iron concentrate from industrial iron-bearing tailings according to claim 1, characterized in that, In step S3, the amount of the composite activating agent added is 0.8%-1.5% of the weight of the tailings powder.

4. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 1, characterized in that, In step S3, the composite activating agent is composed of calcium oxide, calcium fluoride and sodium carbonate in a mass ratio of (5-7):(2-3):

1.

5. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 1, characterized in that, In step S3, the activation temperature is 55-75℃, the stirring speed is 300-400 r / min, and the activation time is 15-25 min.

6. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 1, characterized in that, In step S4, the activated slurry is fed into a wet permanent magnet roller separator for a first-stage magnetic separation with a magnetic field strength of 3000-5000 Gs to obtain a first-stage magnetic concentrate.

7. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 6, characterized in that, In step S4, the first-stage magnetic concentrate is fed into a weak magnetic separator for second-stage magnetic separation. The magnetic field strength is 800-1500 Gs, and the magnetic field strength of the second-stage magnetic separation is less than 1 / 3 of that of the first-stage magnetic separation, thus obtaining the second-stage magnetic concentrate.

8. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 1, characterized in that, In step S5, the slurry is adjusted to a mass concentration of 25%-35%, the pH of the slurry is adjusted to 8.5-9.5 with sodium carbonate, stirred for 3-5 minutes, and then an anionic collector equivalent to 0.1%-0.25% of the tailings powder mass is added, stirred for 2-3 minutes, and then reverse flotation desilication is carried out.

9. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 8, characterized in that, In step S5, the inhibitor is starch; the collector is an anionic collector selected from at least one of sodium oleate, sodium stearate, sodium linoleate, oxidized paraffin soap, tal oil, benzoyl hydroxamic acid, and salicylic acid.

10. A method for extracting iron concentrate from industrial iron-bearing tailings according to claim 8 or 9, characterized in that, In step S5, the following steps are used to perform one coarse selection, one sweep selection, and two fine selections: Step S501, roughing: The slurry after slurry preparation enters the roughing flotation cell, is aerated and stirred for 5-8 minutes, and 50-70% collector is added for roughing. The roughing froth enters the scavenging step, and the roughing underflow enters the first cleaning step. Step S502, Scavenging: The roughing froth enters the scavenging flotation cell, the remaining collector is added, aeration and stirring are carried out for 3-5 minutes, the scavenging froth is discharged as the final tailings, and the scavenging underflow is returned to the roughing operation. Step S503, First Cleaning: The underflow from the roughing stage enters the first cleaning flotation cell without adding collector, and is aerated and stirred for 4-6 minutes; the foam from the first cleaning stage is returned to the roughing stage, and the underflow from the first cleaning stage enters the second cleaning stage; Step S504, Second Cleaning: The underflow from the first cleaning enters the second cleaning flotation cell without adding collector, and is aerated and stirred for 3-5 minutes; the froth from the second cleaning returns to the first cleaning operation, and the underflow from the second cleaning is the final flotation concentrate, which enters the next process.