Low-carbon and high-efficiency beneficiation method for iron ore

Abstract

The invention discloses an iron ore low-carbon efficient beneficiation method, and belongs to the technical field of mineral processing, the iron ore low-carbon efficient beneficiation method comprises the following specific implementation steps: step 1, crushing, rolling, grinding and screening magnetic iron ore, step 2, carrying out fine ore circulating dry separation and grinding separation on a product, and step 3, carrying out low-carbon high-efficiency beneficiation on the product. The method comprises the following steps of 1, carrying out primary ore grinding, 2, carrying out secondary ore grinding, 3, carrying out dry classification, secondary ore grinding and secondary classification on primary concentrate, 4, carrying out product mixing, 5, carrying out product size mixing, 6, carrying out wet low-intensity magnetic separation and secondary magnetic separation on the product, 7, carrying out product concentration to obtain a concentrate product, and 8, carrying out tailing mixing to obtain final wet tailings. The method can effectively meet the industrial production requirements, and has the advantages of short flow, simple process, stable product index, low energy consumption, good economical efficiency and efficient utilization of resources.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and more specifically, to a low-carbon and high-efficiency beneficiation method for iron ore. Background Technology

[0002] The dry grinding and beneficiation technology of Huanmo Technology mainly consists of a toothed roller high-pressure roller mill (a new type of roller mill), an air classifier, an air-gravity magnetic separator, an automatic control integrated system, and a supporting dust removal and protection system. This system adopts a short-process design, a completely waterless process, and negative pressure operation, realizing the concept of "replacing grinding with crushing and early disposal" in mineral processing, achieving the goals of energy saving, cost reduction, high efficiency, and environmental protection.

[0003] Wet grinding and wet separation is a production method in which materials are ground into a slurry by adding water. Wet grinding produces products with uniform fineness, low energy consumption per unit weight of product, no dust emission, and lower noise. It is widely used in chemical, ceramic, cement, and other industrial sectors.

[0004] Currently, dry grinding and wet grinding processes each have their own strengths. However, if it is necessary to obtain excellent mineral processing technical indicators while significantly reducing production costs, neither dry grinding nor wet grinding processes can adequately meet the application requirements.

[0005] Therefore, in view of this, we will study and improve the existing structure to provide a low-carbon and efficient beneficiation method for iron ore, in order to achieve a more practical purpose. Summary of the Invention

[0006] 1. Technical problems to be solved

[0007] In view of the problems existing in the prior art, the purpose of this invention is to provide a low-carbon and high-efficiency beneficiation method for iron ore, which can achieve the following:

[0008] 2. Technical Solution

[0009] To solve the above problems, the present invention adopts the following technical solution.

[0010] A low-carbon and high-efficiency beneficiation method for iron ore, the specific implementation steps of which are as follows:

[0011] Step 1: Crushing, roller milling and screening of magnetite ore: Crush the magnetite ore to a particle size of 0-25mm, feed it into a primary rack-and-tooth high-pressure roller mill for roller milling, and obtain product A;

[0012] Step 2: Dry separation and grinding of fine ore: Roller mill product A is fed to a dry magnetic separator for fine ore dry separation. The particle size of the concentrate product from the magnetic separator is 0-0.5mm, and the concentrate grade reaches ≥45.0%. Then, the ore product in the magnetic separator is returned to the high-pressure roller mill for re-grinding via a belt conveyor, forming a closed-circuit dry grinding and magnetic separation to obtain primary concentrate product B.

[0013] Step 3: Dry classification, secondary grinding and secondary classification of primary concentrate: The primary concentrate product B from the magnetic separator is fed to the air classifier for dry classification. The coarse-grained sand product from the classifier is fed to the secondary rack and pinion high-pressure roller mill for secondary grinding. The ground product is returned to the air classifier for secondary classification via a belt conveyor, forming a closed-loop dry grinding and classification process to obtain product C.

[0014] Step 4: Mix the products: Mix the fine-particle product C from the wind classifier with the dust collector ash to form the final dry grinding coarse concentrate product D;

[0015] Step 5: Prepare the slurry: Add water to the dry milling rough concentrate product D and feed it into the slurry mixing tank for preparation. The mixing time is 10-30 seconds and the slurry concentration is 30% to obtain product E.

[0016] Step 6: Perform wet weak magnetic separation and secondary magnetic separation of the product: Use a slurry pump to transport the slurry product E to the primary magnetic separator for wet weak magnetic separation. After adding water to adjust the slurry in the primary magnetic separator, the concentrate is fed to the secondary magnetic separator for magnetic separation again to obtain product F.

[0017] Step 7: Select and refine the product to obtain concentrate: After adding water to adjust the slurry, the concentrate F from the secondary magnetic separator is fed to the electromagnetic separator for further upgrading and refining to obtain the final concentrate G.

[0018] Step 8: Mix the tailings to obtain the final wet tailings: Mix the tailings from the primary and secondary magnetic separators in Step 6 with the tailings from the cleaning machine in Step 7 to obtain the final wet tailings H, which will be discharged into the tailings dam.

[0019] Furthermore, in step one, the particle size range of product A after grinding is 0-10 mm;

[0020] Among them, the content of product A with a particle size of -0.076mm is ≥35%.

[0021] Furthermore, in step two, when performing dry separation of fine ore, the magnetic separator strength is controlled to be 3000-7500 Oe;

[0022] After closed-circuit dry grinding and magnetic separation, the tailings product of the magnetic separator is the final tailings that are discharged and discarded.

[0023] Furthermore, in step three, a wind-gravity magnetic separator is used for dry magnetic separation of coarse-grained ore powder.

[0024] Furthermore, in step four, the grade of product D concentrate is ≥45.0%, and the content of -0.076mm particle size is ≥95%.

[0025] Furthermore, in step six, both the primary and secondary magnetic separators are drum-type permanent magnet separators with a magnetic field strength of 2000–3500 Oe.

[0026] Furthermore, in step seven, the electromagnetic separator is an electromagnetic magnetic recombining separator, and the iron grade of the final concentrate product G is ≥66.0%, and the final iron metal recovery rate is ≥70%.

[0027] Furthermore, in step seven, when using an electromagnetic cleaner for selection, the current of the electromagnetic cleaner is controlled to be 0.5–2A, and the upward water flow velocity is 5–30 cm / s.

[0028] 3. Beneficial effects

[0029] Compared with the prior art, the advantages of this invention are:

[0030] This method obtains a rough concentrate product with a content of ≥95% in the -0.076mm particle size and full liberation of iron minerals through dry grinding and classification of iron ore and dry magnetic separation of coarse particles. Then, the rough concentrate powder is mixed with water to form a slurry, wet weak magnetic separation, and electromagnetic upgrading and cleaning to obtain a product with an iron grade of ≥66%. This method has a short process, simple technology, stable product indicators, low energy consumption, good economic efficiency, and efficient utilization of resources, which can effectively meet the production needs of industry. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a low-carbon and high-efficiency iron ore beneficiation method according to the present invention. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Example:

[0034] Please see Figure 1 A low-carbon and high-efficiency iron ore beneficiation method is proposed, and the specific implementation steps of this method are as follows:

[0035] Step 1: Crushing, roller milling, and screening of magnetite ore:

[0036] First, the raw material for iron ore was selected, which was magnetite ore from the Bon mine in Liberia.

[0037] Then, a multi-element chemical analysis of the ore was performed, and the results are shown in the table below:

[0038] Components TFe FeO <![CDATA[Fe2O3]]> <![CDATA[SiO2]]> <![CDATA[TiO2]]> <![CDATA[Al2O3]]> CaO content 35.87 11.40 38.57 43.53 0.045 1.31 0.89 Components MgO MnO <![CDATA[Na2O]]> <![CDATA[K2O]]> P S total content 1.54 0.041 0.23 0.56 0.056 0.086 100.00

[0039] Multi-element chemical analysis of the ore showed that the grade of the valuable element Fe was 35.87%, and the TFe / FeO ratio of the sample was 3.15. The gangue component was mainly SiO2, with a content of 43.53%, while the contents of impurity elements P and S were both low.

[0040] The ratio (CaO+MgO) / (SiO2+Al2O3) = 0.05 indicates that the ore is an acidic iron ore.

[0041] Then, iron phase analysis was performed on the ore, and the results are shown in the table below:

[0042] iron phase Iron in magnetite Iron in siderite Iron in hematite Iron in sulfides Iron in silicates total content(%) 24.19 0.07 9.06 0.04 2.51 35.87 Distribution rate (%) 67.43 0.20 0.20 25.26 0.12 100.00

[0043] Next, the mineral composition and content of the ore are determined. The mineral composition of the ore includes: metallic minerals: magnetite, hematite (spectrophyllite and pseudomorphite), pyrite, and limonite. Gangue minerals: quartz, amphibole (common amphibole, actinolite), mica (biotite, phlogopite), almandine, talc, calcite, feldspar, and apatite;

[0044] To determine the content of each component in a mineral, 0-2 mm samples were ground into smooth and thin sections. The content of each mineral was then statistically analyzed under a microscope using the line segment method. Simultaneously, the mineral content was calculated based on the results of scanning electron microscopy (SEM) and EDS analysis. The results are expressed as weight percentages (wt%). The statistical results are shown in the table below:

[0045] Mineral Name Content (wt%) Mineral Name Content (wt%) magnetite 33.85 Almandine 2.80 Hematite 13.15 talc 0.46 Pyrite 0.09 calcite 0.12 quartz 35.63 Feldspar 0.08 amphibole 8.67 other 0.11 mica 5.04 total 100.00

[0046] The analysis results show that the content of the useful iron mineral magnetite is 33.85%, and the content of the minor iron mineral hematite is 13.15%. The gangue mineral is mainly quartz, with a content of 35.63%, followed by amphibole and mica, with contents of 8.67% and 5.04% respectively. Other minerals have relatively low contents.

[0047] Then, the magnetite ore with an iron content of 35.35% is crushed to a particle size of 0-25mm and fed into a primary rack-and-tooth high-pressure roller mill for roller grinding to obtain product A;

[0048] Among them, the primary rack-type high-pressure roller mill is GYM200120, and the particle size range of product A after grinding is 0-10mm.

[0049] Step 2: Dry separation and grinding of powdered ore: Roller mill product A is fed to dry magnetic separator for powdered ore dry separation. The dry magnetic separator is a CLD1030B magnetic separator with the magnetic field strength controlled at 3000-7500 Oe.

[0050] The particle size of the concentrate product from the magnetic separator is 0-0.5mm, and the grade of the concentrate reaches ≥45.0%. Then, the mineral product in the magnetic separator is returned to the high-pressure roller mill for re-grinding via a belt conveyor, forming a closed-circuit dry grinding magnetic separation to obtain first-grade concentrate product B.

[0051] After closed-circuit dry grinding and magnetic separation, the magnetic iron content of the tailings product of the magnetic separator is ≤0.7%, which is the final tailings and is discharged and discarded.

[0052] Step 3: Dry classification, secondary grinding and secondary classification of primary concentrate: The primary concentrate product B of the magnetic separator is fed to the air classifier for dry classification, wherein the selected air classifier is an FL separator.

[0053] Then, the coarse-grained sand product from the classifier is fed into a secondary rack-type high-pressure roller mill for secondary grinding. The selected secondary rack-type high-pressure roller mill is model GYM200120.

[0054] After grinding, the product is returned to the air classifier via a belt conveyor for secondary classification, forming a closed-loop dry grinding and classification process to obtain product C.

[0055] Step 4: Mix the products: Mix the fine-particle product C from the wind classifier with the dust collector ash to form the final dry grinding coarse concentrate product D.

[0056] Among them, the grade of product D concentrate is ≥45.0%, and the content of -0.076mm particle size is ≥95%.

[0057] Step 5: Prepare the slurry: Add water to the dry mill rough concentrate product D and feed it into the slurry mixing tank for preparation. A 6.0m×6.0m mixing and storage tank is selected.

[0058] Among them, the stirring time is controlled at 10-30 seconds, the slurry concentration is 30%, and product E is obtained;

[0059] Step 6: Perform wet weak magnetic separation and secondary magnetic separation of the product: Use a slurry pump to transport the slurry product E to the primary magnetic separator for wet weak magnetic separation. The primary magnetic separator is a Φ1240 permanent magnet drum magnetic separator, and the magnetic field strength is controlled to be 2000~3500Oe.

[0060] Then, after the concentrate from the primary magnetic separator is mixed with water and slurry, it is fed to the secondary magnetic separator for further magnetic separation. The secondary magnetic separator is also a Φ1240 permanent magnet drum magnetic separator, with the magnetic field strength controlled at 2000~3500Oe.

[0061] At this point, product F is obtained;

[0062] Step 7: Select and refine the product to obtain concentrate: After adding water to adjust the slurry, the concentrate F from the secondary magnetic separator is fed to the electromagnetic separator for further upgrading and refining. The electromagnetic separator used is a Φ2000 separator.

[0063] When using an electromagnetic separator for water purification, the current of the electromagnetic separator should be controlled at 0.5–2A, and the upward water flow velocity should be 5–30 cm / s.

[0064] In this way, the final concentrate product G is obtained, with an iron grade of ≥66.0% and a final iron metal recovery rate of ≥70%.

[0065] Step 8: Mix the tailings to obtain the final wet tailings: Mix the tailings from the primary and secondary magnetic separators in Step 6 with the tailings from the cleaning machine in Step 7 to obtain the final wet tailings H, which will be discharged into the tailings dam.

[0066] In summary, this low-carbon and high-efficiency iron ore beneficiation method obtains a rough concentrate product with a content of ≥95% in the -0.076mm particle size and fully liberated iron minerals through dry grinding and classification of iron ore and dry magnetic separation of coarse particles. Then, the rough concentrate powder is mixed with water to form a slurry, followed by wet weak magnetic separation and electromagnetic upgrading to obtain a product with an iron grade of ≥66%. This method has a short process flow, simple technology, stable product indicators, low energy consumption, good economic efficiency, and efficient utilization of resources, which can effectively meet the production needs of industry.

[0067] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A low-carbon and high-efficiency beneficiation method for iron ore, characterized in that: The specific implementation steps of this mineral processing method are as follows: Step 1: Crushing, roller milling and screening of magnetite ore: Crush the magnetite ore to a particle size of 0-25mm, feed it into a primary rack-and-tooth high-pressure roller mill for roller milling, and obtain product A; Step 2: Dry separation and grinding of fine ore: Roller mill product A is fed to a dry magnetic separator for fine ore dry separation. The particle size of the concentrate product from the magnetic separator is 0-0.5mm, and the concentrate grade reaches ≥45.0%. Then, the ore product in the magnetic separator is returned to the high-pressure roller mill for re-grinding via a belt conveyor, forming a closed-circuit dry grinding and magnetic separation to obtain primary concentrate product B. Step 3: Dry classification, secondary grinding and secondary classification of primary concentrate: The primary concentrate product B from the magnetic separator is fed to the air classifier for dry classification. The coarse-grained sand product from the classifier is fed to the secondary rack and pinion high-pressure roller mill for secondary grinding. The ground product is returned to the air classifier for secondary classification via a belt conveyor, forming a closed-loop dry grinding and classification process to obtain product C. Step 4: Mix the products: Mix the fine-particle product C from the wind classifier with the dust collector ash to form the final dry grinding coarse concentrate product D; Step 5: Prepare the slurry: Add water to the dry milling rough concentrate product D and feed it into the slurry mixing tank for preparation. The mixing time is 10-30 seconds and the slurry concentration is 30% to obtain product E. Step 6: Perform wet weak magnetic separation and secondary magnetic separation of the product: Use a slurry pump to transport the slurry product E to the primary magnetic separator for wet weak magnetic separation. After adding water to adjust the slurry in the primary magnetic separator, the concentrate is fed to the secondary magnetic separator for magnetic separation again to obtain product F. Step 7: Select and refine the product to obtain concentrate: After adding water to adjust the slurry, the concentrate F from the secondary magnetic separator is fed to the electromagnetic separator for further upgrading and refining to obtain the final concentrate G. Step 8: Mix the tailings to obtain the final wet tailings: Mix the tailings from the primary and secondary magnetic separators in Step 6 with the tailings from the cleaning machine in Step 7 to obtain the final wet tailings H, which will be discharged into the tailings dam.

2. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step one, the particle size range of product A after grinding is 0-10 mm. Among them, the content of product A with a particle size of -0.076mm is ≥35%.

3. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step two, when dry separation of fine ore is carried out, the magnetic separator strength is controlled to be 3000-7500 Oe; After closed-circuit dry grinding and magnetic separation, the tailings product of the magnetic separator is the final tailings that are discharged and discarded.

4. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step three, a dry magnetic separation of coarse-grained ore powder is carried out using an air-gravity magnetic separator.

5. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step four, the grade of product D concentrate is ≥45.0%, and the content of -0.076mm particle size is ≥95%.

6. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step six, both the primary and secondary magnetic separators are drum-type permanent magnet separators with a magnetic field strength of 2000–3500 Oe.

7. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step seven, the electromagnetic separator is an electromagnetic magnetic recombining separator, and the iron grade of the final concentrate product G is ≥66.0%, and the final iron metal recovery rate is ≥70%.

8. The low-carbon and high-efficiency iron ore beneficiation method according to claim 1, characterized in that: In step seven, when using an electromagnetic cleaner for selection, the current of the electromagnetic cleaner is controlled to be 0.5 to 2A, and the upward water flow velocity is 5 to 30 cm / s.

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