Beneficiation method for preparing multi-product iron concentrate from lean magnetite ore

Abstract

The application discloses a beneficiation method for preparing multiple product iron concentrates from lean magnetite ore, and the method steps are as follows: 1) feeding the lean magnetite ore with a particle size of 25-20 mm into a high-pressure roller mill-wet magnetic separation pre-concentration operation, crushing the high-pressure roller mill product to a particle size of 3-0 mm, and obtaining pre-concentration concentrate and pre-concentration tailings; 2) feeding the pre-concentration concentrate into a first-stage grinding-magnetic separation operation for separation, and obtaining first-stage weak magnetic concentrate and first-stage weak magnetic tailings; 3) feeding the first-stage weak magnetic concentrate into a second-stage grinding-magnetic separation operation for separation, and obtaining second-stage weak magnetic concentrate and second-stage weak magnetic tailings; 4) feeding the second-stage weak magnetic concentrate into a tower mill-three-stage magnetic separation-elution operation for separation, and obtaining high-purity iron concentrate, elution middlings and three-stage weak magnetic tailings; 5) performing concentration treatment on the elution middlings to obtain concentrated underflow slurry; and 6) feeding the concentrated underflow into a reverse flotation operation to obtain high-purity iron concentrate and flotation tailings. The method improves the elution efficiency, and increases the product diversity and flexibility.

Description

Technical Field

[0001] This invention relates to a mineral processing method, and more particularly to a mineral processing method for preparing multi-product iron concentrate from lean magnetite ore. Background Technology

[0002] Low-grade magnetite ore is typically crushed to 12-0 mm using traditional crushing processes, followed by two or three stages of grinding and magnetic separation to obtain iron concentrate with a TFe grade of around 66%. However, this method yields a low-grade concentrate, which is unfavorable for subsequent smelting. While washing and beneficiation can improve the concentrate grade, this process results in high-grade tailings, high water consumption, low efficiency, complex process flow, high grinding energy consumption, and low added value of the resulting iron concentrate. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a mineral processing method for preparing multi-product iron concentrate from lean magnetite ore that is highly efficient and economical.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is: (1) feeding lean magnetite ore with a particle size of 25-20mm into a high-pressure roller mill-wet magnetic separation pre-selection operation, the particle size of the crushed product of the high-pressure roller mill is 3-0mm, and obtaining pre-selected concentrate and pre-selected tailings;

[0005] (2) The pre-selected concentrate is fed into a first-stage grinding-magnetic separation operation for separation to obtain a first-stage weak magnetic concentrate and a first-stage weak magnetic tailings;

[0006] (3) The first-stage weak magnetic concentrate is fed into the second-stage grinding-magnetic separation operation for separation to obtain the second-stage weak magnetic concentrate and the second-stage weak magnetic tailings;

[0007] (4) The two-stage weak magnetic concentrate feed tower mill-three-stage magnetic separation-washing operation is used to obtain high-grade iron concentrate, washed middlings and three-stage weak magnetic tailings;

[0008] (5) The washed ore is concentrated to obtain concentrated underflow slurry;

[0009] (6) The concentrated underflow is fed into the reverse flotation operation to obtain high-purity iron concentrate and flotation tailings.

[0010] Furthermore, the pre-selected tailings, the first-stage weak magnetic tailings, the second-stage weak magnetic tailings, and the flotation tailings are considered as the total tailings.

[0011] Furthermore, in step (2), the grinding fineness of the first grinding stage is controlled at -0.074 mm, accounting for 65% to 70%, and the TFe grade of the first weak magnetic concentrate is 50% to 55%.

[0012] Furthermore, in step (3), the grinding fineness of the second-stage grinding is controlled at -0.074 mm, accounting for 85% to 90%, and the TFe grade of the second-stage weak magnetic concentrate is 63% to 65%.

[0013] Furthermore, in step (4), the grinding fineness of the tower mill is controlled at -0.038mm, accounting for 90% to 95%; the three-stage magnetic separation adopts weak magnetic separation, and the TFe grade of the three-stage weak magnetic concentrate is 64% to 66%; the TFe grade of the high-grade iron concentrate is 68.5% to 70%.

[0014] Furthermore, in step (5), the slurry mass concentration of the concentrated underflow slurry is controlled at 35% to 40%.

[0015] Furthermore, in step (6), the TFe grade of the high-purity iron concentrate is >71%.

[0016] The beneficial effects of adopting the above technical solution are as follows: This invention pre-selects lean magnetite ore with a particle size of 25-20mm through a high-pressure roller mill-wet magnetic separator to obtain a crushed product with a particle size of 3-0mm through pre-selection magnetic separation, and discharges a large amount of tailings; for the pre-selected concentrate with a particle size of 3-0mm, a two-stage grinding-magnetic separation, tower mill-magnetic separation-washing machine is used to obtain a high-grade iron concentrate with a TFe grade ≥68.5%; for the middlings in the washing machine, a reverse flotation process is used, through one roughing, two cleaning, and one scavenging closed-circuit flotation process, to obtain a high-purity iron concentrate with a TFe grade >71%.

[0017] This invention employs a washing machine to first obtain a portion of high-grade iron concentrate, avoiding the recycling of washing machine tailings and increasing throughput. The washing machine tailings are then subjected to magnetic separation concentration, slurry conditioning, and reverse flotation to obtain high-purity iron concentrate. This series magnetic levitation method, which combines washing machine selection to obtain high-grade iron concentrate and washing machine tailings reverse flotation to obtain high-purity iron concentrate, not only improves the efficiency of the washing machine but also increases the diversity and flexibility of iron ore beneficiation products, enhances the added value of iron concentrate, has strong process applicability, and yields significant economic benefits. Attached Figure Description

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0020] Figure 1 As shown, the beneficiation method for preparing multi-product iron concentrate from lean magnetite ore adopts the following steps:

[0021] (1) High-pressure roller mill-wet magnetic separation pre-selection operation: After coarse crushing, medium crushing, fine crushing and screening, the product particle size of the lean magnetite ore reaches 25-20mm. The lean magnetite ore with fine crushing to 25-20mm is fed into the high-pressure roller mill-wet magnetic separation pre-selection operation; a high-pressure roller mill is used for high-pressure roller milling, and the particle size of the high-pressure roller mill crushed product is 3-0mm. The high-pressure roller mill crushed product is fed into a wet magnetic separator to obtain a pre-selected concentrate with a TFe grade of 28%-33% (wt) and a pre-selected tailings with a TFe grade of 9%-12% (wt).

[0022] (2) First-stage grinding-magnetic separation operation: The pre-selected concentrate with a TFe grade of 28% to 33% is fed into a ball mill for first-stage grinding, and the grinding fineness is controlled at -0.074 mm accounting for 65% to 70% (wt); the first-stage grinding product is fed into a magnetic separator for first-stage magnetic separation. The first-stage magnetic separation adopts weak magnetic separation with a magnetic field strength of 143.31 to 159.24 kA / m to obtain a first-stage weak magnetic concentrate and a first-stage weak magnetic tailings; the TFe grade of the first-stage weak magnetic concentrate is 50% to 55%.

[0023] (3) Two-stage grinding-magnetic separation operation: The first-stage weak magnetic concentrate with a TFe grade of 50% to 55% is fed into a ball mill for two-stage grinding, and the grinding fineness is controlled at -0.074mm, accounting for 85% to 90%; the product of the second-stage grinding is fed into a magnetic separator for two-stage magnetic separation. The second-stage magnetic separation adopts weak magnetic separation with a magnetic field strength of 127.39 to 143.31kA / m to obtain the second-stage weak magnetic concentrate and the second-stage weak separation tailings; the TFe grade of the second-stage weak magnetic concentrate is 63% to 65%.

[0024] (4) Tower mill-three-stage magnetic separation-washing operation: The two-stage weak magnetic concentrate with a TFe grade of 63% to 65% is fed into the tower mill for tower milling, and the grinding fineness is controlled at -0.038mm, accounting for 90% to 95%; the tower mill product is fed into the magnetic separator for three-stage magnetic separation, and the three-stage magnetic separation adopts weak magnetic separation with a magnetic field strength of 127.39 to 143.31kA / m, to obtain three-stage weak magnetic concentrate and three-stage weak magnetic tailings; the TFe grade of the three-stage weak magnetic concentrate is 64% to 66%; the three-stage weak magnetic concentrate is fed into the washing machine for washing, to obtain high-grade iron concentrate with a TFe grade of 68.5% to 70% and middlings.

[0025] (5) Thickening and reverse flotation operations: The washed middlings are thickened, and the mass concentration of the thickened underflow slurry is controlled at 35% to 40%; the thickened underflow slurry is fed into the reverse flotation operation, which is an anionic reverse flotation at room temperature, using a closed-circuit process of one roughing, two cleaning, and one scavenging. The reagent system is as follows: the roughing collector dosage is 700g / t to 800g / t, the NaOH dosage is 1200 to 1400g / t, the causticized starch dosage is 1200 to 1400g / t, the CaO dosage is 550 to 650g / t, and the scavenging collector dosage is 300g / t to 400g / t; finally, high-purity iron concentrate with a TFe grade > 71% and flotation tailings are obtained.

[0026] (6) The high-grade iron concentrate with a TFe grade of 68.5% to 70% and the high-purity iron concentrate with a TFe grade of >71% can be used as raw materials for subsequent metallurgy; the pre-selection tailings, the first-stage weak magnetic tailings, the second-stage weak selection tailings, the third-stage weak magnetic tailings and the flotation tailings are used as the total tailings.

[0027] Example 1: The specific mineral processing method for preparing multi-product iron concentrate from lean magnetite ore is as follows.

[0028] (1) After coarse crushing, medium crushing, fine crushing and screening, the lean magnetite ore with a TFe grade of 19.78% and a magnetic iron content of 13.55% is fed into a high-pressure roller mill-wet magnetic separation pre-selection operation. The high-pressure roller mill crushes the product with a particle size of 3-0mm, and obtains a pre-selected concentrate with a TFe grade of 29.8% and a pre-selected tailings with a TFe grade of 9.2%.

[0029] (2) The pre-selected concentrate is fed into a first-stage grinding-magnetic separation operation. The grinding fineness is controlled at -0.074mm, accounting for 65%. The magnetic field strength of the first-stage magnetic separation is 143.31kA / m, and a first-stage weak magnetic concentrate and a first-stage weak magnetic tailings with a TFe grade of 50.7% are obtained.

[0030] (3) The first stage of weak magnetic concentrate is fed into the second stage of grinding-magnetic separation. The grinding fineness is controlled at -0.074mm, accounting for 85%. The magnetic field strength of the second stage magnetic separation is 127.39kA / m, and the second stage weak magnetic concentrate and the second stage weak separation tailings with Fe grade of 63.2% are obtained.

[0031] (4) The two-stage weak magnetic concentrate feed tower mill-three-stage magnetic separation-washing operation, the grinding fineness is controlled at -0.038mm accounting for 90%, the magnetic field strength of the three-stage magnetic separation is 127.39kA / m, and the three-stage weak magnetic concentrate with Fe grade of 64.6% is obtained; the three-stage weak magnetic concentrate is fed into the washing machine for washing, and high-grade iron concentrate with TFe grade of 68.5% and middlings are obtained.

[0032] (5) The washed ore is concentrated, and the mass concentration of the concentrated underflow slurry is controlled at 35%; the concentrated underflow slurry is fed into the reverse flotation operation, which is a room temperature anionic reverse flotation, using a closed-circuit process of one roughing, two cleaning, and one scavenging. The reagent system is as follows: the amount of roughing collector is 700g / t, the amount of NaOH is 1200g / t, the amount of causticized starch is 1200g / t, the amount of CaO is 550g / t, and the amount of scavenging collector is 300g / t; finally, a high-purity iron concentrate with a TFe grade of 71% and flotation tailings are obtained.

[0033] Example 2: The specific mineral processing method for preparing multi-product iron concentrate from lean magnetite ore is as follows.

[0034] (1) After coarse crushing, medium crushing, fine crushing and screening, the lean magnetite ore with a TFe grade of 20.26% and a magnetic iron content of 13.63% is fed into a high-pressure roller mill-wet magnetic separation pre-selection operation. The high-pressure roller mill crushes the product with a particle size of 3-0mm, and obtains a pre-selected concentrate with a TFe grade of 30.5% and a pre-selected tailings with a TFe grade of 9.5%.

[0035] (2) The pre-selected concentrate is fed into a first-stage grinding-magnetic separation operation. The grinding fineness is controlled at -0.074mm, accounting for 68%. The magnetic field strength of the first-stage magnetic separation is 150kA / m, and a first-stage weak magnetic concentrate and a first-stage weak magnetic tailings with a TFe grade of 52.3% are obtained.

[0036] (3) The first stage of weak magnetic concentrate is fed into the second stage of grinding-magnetic separation. The grinding fineness is controlled at -0.074mm, accounting for 88%. The magnetic field strength of the second stage magnetic separation is 135kA / m, and the second stage weak magnetic concentrate and the second stage weak separation tailings with Fe grade of 64.2% are obtained.

[0037] (4) The two-stage weak magnetic concentrate feed tower mill-three-stage magnetic separation-washing operation, the grinding fineness is controlled at -0.038mm accounting for 92%, the magnetic field strength of the three-stage magnetic separation is 135kA / m, and the three-stage weak magnetic concentrate with Fe grade of 65.3% is obtained; the three-stage weak magnetic concentrate is fed into the washing machine for washing, and high-grade iron concentrate with TFe grade of 69.0% and middlings are obtained.

[0038] (5) The washed ore is concentrated, and the mass concentration of the concentrated underflow slurry is controlled at 37%; the concentrated underflow slurry is fed into the reverse flotation operation, which is a room temperature anionic reverse flotation, using a closed-circuit process of one roughing, two cleaning, and one scavenging. The reagent system is as follows: the amount of roughing collector is 750g / t, the amount of NaOH is 1300g / t, the amount of causticized starch is 1300g / t, the amount of CaO is 600g / t, and the amount of scavenging collector is 350g / t; finally, a high-purity iron concentrate with a TFe grade of 71.10% and flotation tailings are obtained.

[0039] Example 3: The specific mineral processing method for preparing multi-product iron concentrate from lean magnetite ore is as follows.

[0040] (1) After coarse crushing, medium crushing, fine crushing and screening, the lean magnetite ore with a TFe grade of 22.34% and a magnetic iron content of 14.35% is fed into a high-pressure roller mill-wet magnetic separation pre-selection operation. The high-pressure roller mill crushes the product with a particle size of 3-0mm, and obtains a pre-selected concentrate with a TFe grade of 32.8% and a pre-selected tailings with a TFe grade of 11.3%.

[0041] (2) The pre-selected concentrate is fed into a first-stage grinding-magnetic separation operation. The grinding fineness is controlled at -0.074mm, accounting for 70%. The magnetic field strength of the first-stage magnetic separation is 159.24kA / m, and a first-stage weak magnetic concentrate and a first-stage weak magnetic tailings with a TFe grade of 54.6% are obtained.

[0042] (3) The first stage of weak magnetic concentrate is fed into the second stage of grinding-magnetic separation. The grinding fineness is controlled at -0.074mm, accounting for 90%. The magnetic field strength of the second stage magnetic separation is 143.31kA / m, and the second stage weak magnetic concentrate and the second stage weak separation tailings with Fe grade of 64.8% are obtained.

[0043] (4) The two-stage weak magnetic concentrate feed tower mill-three-stage magnetic separation-washing operation, the grinding fineness is controlled at -0.038mm accounting for 95%, the magnetic field strength of the three-stage magnetic separation is 143.31kA / m, and the three-stage weak magnetic concentrate with Fe grade of 66% is obtained; the three-stage weak magnetic concentrate is fed into the washing machine for washing, and high-grade iron concentrate with TFe grade of 69.5% and middlings are obtained.

[0044] (5) The washed ore is concentrated, and the mass concentration of the concentrated underflow slurry is controlled at 40%. The concentrated underflow slurry is fed into the reverse flotation operation. The reverse flotation operation is an anion reverse flotation at room temperature. It adopts a closed-circuit process of one roughing, two cleaning, and one scavenging. The reagent system is as follows: the amount of roughing collector is 800g / t, the amount of NaOH is 1400g / t, the amount of causticized starch is 1400g / t, the amount of CaO is 650g / t, and the amount of scavenging collector is 400g / t. Finally, a high-purity iron concentrate with a TFe grade of 71.4% and flotation tailings are obtained.

Claims

1. A mineral processing method for preparing multi-product iron concentrate from lean magnetite ore, characterized in that, The method and steps are as follows: Step 1: Feed lean magnetite ore with a particle size of 25-20mm into a high-pressure roller mill-wet magnetic separation pre-selection operation. The high-pressure roller mill crushes the product with a particle size of 3-0mm to obtain pre-selected concentrate and pre-selected tailings. Step 2: Feed the pre-selected concentrate into a first-stage grinding-magnetic separation operation for separation to obtain a first-stage weak magnetic concentrate and a first-stage weak magnetic tailings; Step 3: The first-stage weak magnetic concentrate is fed into the second-stage grinding-magnetic separation operation for separation to obtain the second-stage weak magnetic concentrate and the second-stage weak magnetic tailings; Step 4: The two-stage weak magnetic concentrate feed tower mill-three-stage magnetic separation-washing operation is carried out to obtain high-grade iron concentrate, washed middlings and three-stage weak magnetic tailings; Step 5: The washed ore is concentrated to obtain concentrated underflow slurry; Step 6: The concentrated underflow is fed into the reverse flotation operation to obtain high-purity iron concentrate and flotation tailings.

2. The beneficiation method for preparing multi-product iron concentrate from lean magnetite ore according to claim 1, characterized in that: The pre-selected tailings, the first-stage weak magnetic tailings, the second-stage weak magnetic tailings, and the flotation tailings are referred to as the total tailings.

3. The beneficiation method for preparing multi-product iron concentrate from lean magnetite ore according to claim 1, characterized in that: In step 2, the grinding fineness of the first-stage grinding is controlled at -0.074 mm, accounting for 65% to 70%, and the TFe grade of the first-stage weak magnetic concentrate is 50% to 55%.

4. The beneficiation method for preparing multi-product iron concentrate from lean magnetite ore according to claim 1, characterized in that: In step 3, the grinding fineness of the second-stage grinding is controlled at -0.074 mm, accounting for 85% to 90%, and the TFe grade of the second-stage weak magnetic concentrate is 63% to 65%.

5. The beneficiation method for preparing multi-product iron concentrate from lean magnetite ore according to claim 1, characterized in that: In step 4, the grinding fineness of the tower mill is controlled at 90% to 95% to -0.038 mm; the three-stage magnetic separation adopts weak magnetic separation, and the TFe grade of the three-stage weak magnetic concentrate is 64% to 66%; the TFe grade of the high-grade iron concentrate is 68.5% to 70%.

6. The beneficiation method for preparing multi-product iron concentrate from lean magnetite ore according to claim 1, characterized in that: In step 5, the mass concentration of the concentrated underflow slurry is controlled at 35% to 40%.

7. The beneficiation method for preparing multi-product iron concentrate from lean magnetite ore according to any one of claims 1-6, characterized in that: In step 6, the TFe grade of the high-purity iron concentrate is >71%.

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