A beneficiation method for stabilizing production indexes when simultaneously beneficiating multiple different properties of iron ore

Abstract

The application discloses a beneficiation method for stably improving production indexes when multiple iron ores with different properties are simultaneously beneficiated. The method is as follows: iron ores are ground by a semi-autogenous mill and then enter a GK screen, the oversize material is thrown away by a magnetic drum, and the throwed concentrate returns to the semi-autogenous mill for regrinding; the undersize material of the GK screen is transported to a cyclone classifier by a slurry pump, the cyclone classifier sand enters a ball mill for regrinding, the ball mill grinding product is transported to the cyclone classifier by the slurry pump, the cyclone classifier overflow with a fineness of 73-78% of 200 mesh is transported to a first-stage low-intensity magnetic separator by the slurry pump; the first-stage low-intensity magnetic concentrate is beneficiated by a tower mill three-stage grinding, a low-intensity magnetic separator and a full-automatic elutriation machine to obtain a magnetite concentrate, and the first-stage high-intensity magnetic concentrate is beneficiated by two-stage grinding, high-intensity magnetic separation and gravity separation to obtain a hematite concentrate. The beneficiation method can stably improve the production indexes when multiple iron ores with different properties are simultaneously beneficiated, reduce the production cost and improve the profit.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a mineral processing method that stably improves production indicators when multiple iron ores of different properties are simultaneously fed into the beneficiation process. Background Technology

[0002] The Dahongshan No. 3 beneficiation plant produces a variety of iron ore, including open-pit lava iron ore, underground low-grade iron ore, and the Erdaogou iron ore mine. The supply of each ore is unstable, and their respective proportions fluctuate frequently, leading to frequent fluctuations in iron ore beneficiation indicators, such as iron ore processing capacity, iron concentrate grade, and iron tailings grade. This invention aims to provide a beneficiation method that stabilizes and improves production indicators when multiple iron ores of different properties are simultaneously fed into the beneficiation process, thereby stabilizing and enhancing iron ore processing capacity, concentrate quality, and concentrate recovery rate. Summary of the Invention

[0003] To address the aforementioned problems, the purpose of this invention is to provide a mineral processing method that can stably improve production indicators when multiple iron ores of different properties are simultaneously fed into the beneficiation process.

[0004] The objective of this invention is achieved by providing a mineral processing method that stably improves production indicators when multiple iron ores of different properties are simultaneously fed into the beneficiation process, through the following steps:

[0005] 1) After being ground in a semi-autogenous mill, the iron ore enters a GK screen. The material on the screen is discarded by a magnetic drum, and the concentrate is returned to the semi-autogenous mill for further grinding.

[0006] 2) The slurry under the GK screen is pumped to the hydrocyclone group for classification by a slurry pump. The hydrocyclone underflow enters the ball mill for regrinding. The ball mill grinding product is pumped to the hydrocyclone group for classification by a slurry pump. The hydrocyclone overflow with a fineness of -200 mesh accounting for 73-78% is pumped to a weak magnetic section by a slurry pump.

[0007] 3) The weak magnetic tailings from the first stage enter the first stage slag screen. The undersize material from the slag screen enters the first stage strong magnetic screen. The oversize material from the slag screen and the weak magnetic concentrate from the first stage enter the grinding and classification system of three tower mills. The weak magnetic concentrate from the first stage is separated into magnetite concentrate by three stages of grinding in the tower mill, weak magnetic separator and fully automatic washing machine. The strong magnetic concentrate from the first stage is separated into hematite concentrate by two stages of grinding, strong magnetic separation and gravity separation.

[0008] 4) Two full-disk tailings recovery machines are used to recover magnetite from the tailings of the washing machine and feed it into the tower mill grinding and classification system and subsequent processes for re-grinding and re-selection.

[0009] The beneficial effects of this invention are: the mineral processing method of this invention can stably improve the production indicators when multiple iron ores of different properties are simultaneously fed into the beneficiation process, thereby reducing production costs and increasing profits. Attached Figure Description

[0010] Figure 1The iron series production flow chart for the original Dahongshan No.

[0011] Figure 2 The iron series production flow chart for the underground iron ore with the proportion less than 50% in the present application;

[0012] Figure 3 The iron series production flow chart for the underground iron ore with the proportion greater than 50% in the present application;

[0013] Figure 4 The iron series semi-autogenous mill sand return and discarding flow chart for the No. DETAILED DESCRIPTION

[0014] The present application is further described below in combination with the embodiments and the drawings, but is not limited in any way by the present application, and any transformation based on the present application belongs to the protection scope of the present application.

[0015] The beneficiation method for stably improving the production indexes when multiple different properties of iron ore are selected at the same time in the present application is realized according to the following steps:

[0016] 1) The iron ore is ground in a semi-autogenous mill and then enters a GK screen, the oversize material is discarded by a magnetic drum, and the discarding concentrate returns to the semi-autogenous mill for regrinding;

[0017] 2) The undersize material of the GK screen is transported to a cyclone classifier by a slurry pump, the cyclone classifier sand is regrinded in a ball mill, the ball mill grinding product is transported to the cyclone classifier by a slurry pump, and the cyclone classifier overflow with a fineness of 73-78% of-200 mesh is transported to a first-stage low-intensity magnetic separation by a slurry pump;

[0018] 3) The first-stage low-intensity magnetic separation tailings enter a first-stage desliming screen, the undersize material of the first-stage desliming screen enters a first-stage high-intensity magnetic separation, and the oversize material of the first-stage desliming screen and the first-stage low-intensity magnetic separation concentrate enter a three-tower mill grinding classification system; the first-stage low-intensity magnetic separation concentrate is selected by a tower mill grinding, a low-intensity magnetic separator and a full-automatic elutriator to obtain a magnetite concentrate, and the first-stage high-intensity magnetic separation concentrate is selected by a high-intensity magnetic separation and a gravity separation to obtain a hematite concentrate;

[0019] 4) Two full-disk type tailings recovery machines are used to recover the magnetite from the elutriator tailings into the tower mill grinding classification system and the subsequent regrinding and reselection process.

[0020] In step 3), the overflow of the Φ350*12 cyclone classifier is fed to the second-stage weak magnetic separation by gravity flow, and the overflow of the second-stage weak magnetic separation is fed to the 6400m2 inclined plate thickener by gravity flow; the overflow of the inclined plate thickener is fed to the third-stage weak magnetic separation by gravity flow, and the overflow of the third-stage weak magnetic separation is fed to the shaking table for separation; the overflow of the shaking table is directly discarded, and the overflow of the third-stage weak magnetic separation is combined with the overflow of the shaking table to obtain the recovered iron concentrate.

[0021] The overflow of the 1# full-disk tailings recovery machine is fed to the 2# full-disk tailings recovery machine for sweeping selection, and the overflow of the 1# and 2# full-disk tailings recovery machines is returned to the tower mill grinding and classification system for regrinding; the overflow of the 2# full-disk tailings recovery machine is fed to the ditch for discarding.

[0022] In step 3), the overflow of the Φ350*12 cyclone classifier is fed to the second-stage weak magnetic separation by gravity flow, and the overflow of the second-stage weak magnetic separation is fed to the 6400m2 inclined plate thickener by gravity flow; the overflow of the inclined plate thickener is fed to the third-stage weak magnetic separation by gravity flow, and the overflow of the third-stage weak magnetic separation is fed to the shaking table for separation; the overflow of the shaking table is directly discarded, and the overflow of the third-stage weak magnetic separation is combined with the overflow of the shaking table to obtain the recovered iron concentrate.

[0023] The magnetic iron is recovered by the full-disk tailings recovery machine before the second-stage strong magnetic separation.

[0024] In step 3), when the proportion of underground ore is more than 50%, the first-stage strong magnetic separation adopts a one-stage roughing, one-stage cleaning and one-stage scavenging process; when the proportion of underground ore is less than 50%, the first-stage strong magnetic separation adopts a one-stage roughing and two-stage cleaning process.

[0025] In step 1), the discarded waste rock is fed to the waste rock warehouse and transported by vehicles for external sales.

[0026] In step 1), the semi-autogenous mill is of the MZS8848 type.

[0027] In step 2), the cyclone classifier is of the Φ660*12 type, and the ball mill is of the MQY6095 type.

[0028] Example 1: Mineral processing system transformation

[0029] 1. The GK screen return sand conveyor belt for the iron series semi-autogenous mill has three conveyor belts: Melting 7#, Melting 8#, and Melting 9#. The first roller of the Melting 7# conveyor belt will be replaced with a magnetic pulley (500mm diameter, 550mT magnetic field strength). The ore hopper of the existing Melting 8# conveyor belt under the Melting 7# conveyor belt will be modified into a double-channel hopper. The concentrate from the waste separation enters the Melting 8# conveyor belt, and then enters the Melting 9# conveyor belt to return to the semi-autogenous mill for re-grinding. New Waste Disposal 1# and Waste Disposal 2# conveyor belts and a waste rock bin will be constructed. Waste rock from the waste separation enters the Waste Disposal 1# conveyor belt, then enters the waste rock bin, and finally, the waste rock is discharged to transport vehicles for sale through the Waste Disposal 2# conveyor belt at the bottom of the waste rock bin. Figure 4 As shown.

[0030] 2. Through process modification, the first-stage strong magnetic concentrate (mainly hematite) is introduced into the Melting Pump Pool 11, and then pumped into a 6400m² inclined plate thickener. The underflow from the inclined plate is then pumped to the pre-slag screen of the second-stage strong magnetic concentrate. After the modification, the first-stage strong magnetic concentrate no longer undergoes grinding and classification in the No. 3 tower mill. The first-stage weak magnetic concentrate is evenly fed to the pump pools of the three tower mills through a distribution box, and then enters the grinding and classification system of the three tower mills. This achieves that the tower mills (third-stage grinding) only process the first-stage weak magnetic concentrate (mainly magnetite). See details. Figure 2 .

[0031] 3. Add two HLW1500-12 full disk tailings recovery machines to process tailings from the washing machine. Specific parameters of the HLW1500-12 full disk tailings recovery machine: field strength 450mT, disk diameter Φ1500mm, number of disks 12, processing particle size 0-3mm, input voltage 380V, 50Hz, motor power 11kW, total weight 6t, and external dimensions 3595(L)×2755(W)×1841(H)mm.

[0032] 4. Modify the flow path of the pipeline from the second-stage strong magnetic field to the third-stage strong magnetic field. Previously, the tailings from the second-stage strong magnetic field were directly discarded. Instead, a gate valve and additional piping were added to the second-stage strong magnetic field tailings pipe to introduce the tailings into the third-stage strong magnetic field feed box. The third-stage strong magnetic field can then be used for either fine or scavenging operations. Adjustments can be made based on the condition of the raw ore during daily production. See details. Figure 3 .

[0033] 5. Add 30 double-layer shaking tables to process the three-stage strong magnetic tailings. The concentrate from the double-layer shaking tables will be incorporated into the recovered iron concentrate, and the tailings from the double-layer shaking tables will be directly discarded. Double-layer shaking table parameters: stroke 11~16mm, stroke rate 300~400 strokes / min, table slope 1°~4.5°, feed rate (dry weight) 48~55 t / unit / day, motor power 1.5KW. See details. Figure 3 .

[0034] 6. Add one new full-disk type tailings recovery magnetic separator, installed on the pre-screening platform of the second-stage high-intensity magnetic separator. This is used to pre-remove magnetic minerals. The concentrate from the tailings recovery magnetic separator enters the grinding and classification system of the tower mill, and the tailings enter the screening process before entering the subsequent high-intensity magnetic and shaking table separation process. Pre-removal of magnetic minerals creates favorable conditions for subsequent high-intensity magnetic and shaking table separation.

[0035] Example 2

[0036] Taking January to November 2024 as an example, the proportion of iron ore from underground mines accounted for 41.84% of the total raw ore, with an iron grade of 20.60% and a magnetic iron grade of 8.80%, representing a magnetic iron content of 42.42%. The beneficiation method is as follows:

[0037] The ore in the mining site is transported by car into the coarse crushing station, and the ore is coarsely crushed to-250mm and then transported by belt to the lava ore warehouse. The iron ore in the lava ore warehouse is ground by the MZS8848 semi-autogenous mill, and then enters the GK screen. The oversize material is discarded by the magnetic drum, and the discarded waste rock enters the waste rock warehouse and is transported by vehicle for external sales. The discarded concentrate (ore) returns to the MZS8848 semi-autogenous mill for regrinding. The undersize material of the GK screen is transported by the slurry pump to the Φ660*12 cyclone classifier, and the cyclone sand enters the MQY6095 ball mill for regrinding. The ground product of the MQY6095 ball mill is transported by the slurry pump to the Φ660*12 cyclone classifier, and the overflow (-200 mesh accounts for 75.68%) is transported by the slurry pump to the first-stage weak magnetic separator. The tailings of the first-stage weak magnetic separator enter the first-stage deslagging screen, and the undersize material enters the first-stage strong magnetic separator. The oversize material of the deslagging screen and the concentrate of the first-stage weak magnetic separator enter the three tower mills for grinding and classification system. The Φ350*12 cyclone group returns the sand to the three tower mills for regrinding, and the ground product of the tower mill is transported by the slurry pump to the Φ350*12 cyclone classifier for classification. The overflow (-325 mesh accounts for 86.09%) is self-flowed to the second-stage weak magnetic separator. The tailings of the second-stage weak magnetic separator are self-flowed to the 6400m² inclined plate thickener, and the concentrate is self-flowed to the third-stage weak magnetic separator. The tailings of the third-stage weak magnetic separator are self-flowed to the tower mill grinding and classification system for regrinding, and the concentrate enters the washing machine. The concentrate of the washing machine is an iron concentrate with an iron grade of 66.68%. The tailings enter the 1# full-disk tailings recovery machine. The tailings of the 1# full-disk tailings recovery machine are swept and selected by the 2# full-disk tailings recovery machine. The concentrate of the 1# and 2# full-disk tailings recovery machines returns to the tower mill grinding and classification system for regrinding, and the tailings of the 2# full-disk tailings recovery machine are self-flowed to the ditch for tailing disposal. The concentrate of the first-stage strong magnetic separator is transported by the slurry pump to the 6400m² inclined plate thickener, and the overflow is recycled water. The underflow is transported by the slurry pump to the full-disk tailings recovery machine. The concentrate is self-flowed to the tower mill grinding and classification system and the subsequent process for regrinding and reselection. The tailings (excluding magnetic iron) enter the second-stage deslagging screen, and the oversize material is self-flowed to the tower mill grinding and classification system. The undersize material enters the second-stage strong magnetic separator. The concentrate of the second-stage strong magnetic separator is self-flowed to the third-stage strong magnetic separator for reselection, and the tailings are self-flowed to the ditch for tailing disposal. The tailings of the third-stage strong magnetic separator are transported by the slurry pump to the shaking table for selection, and the tailings are directly discarded. The concentrate of the third-stage strong magnetic separator and the concentrate of the shaking table are combined to produce an iron concentrate with an iron grade of 36.89%. According to the sales requirements of iron concentrate with an iron grade of more than 64% and a silicon dioxide content of less than 6.00%, the pipeline gate valve of the recovered iron concentrate can be controlled to appropriately mix the recovered iron concentrate into the iron concentrate. From January to November 2024, 4.47 million tons of iron concentrate with an iron grade of 36.89% and 65.54 million tons of washing machine concentrate with an iron grade of 66.68% are mixed to produce 70.01 million tons of iron concentrate with an iron grade of 64.78% and a silicon dioxide content of 5.95%, which is sold to internal units. In addition, 8.29 million tons of iron concentrate with an iron grade of 36.89% is produced for external sales. Details are shown in Figure 2 .

[0038] Example 3

[0039] Taking 2023 as an example, the proportion of underground iron ore of the iron series is 66.51% of the total ore, the iron grade of the ore is 21.97%, the magnetic iron grade of the ore is 9.54%, and the magnetic iron occupancy of the ore is 43.42%. The second and third stage strong magnetic process is different from that of example 2 in the beneficiation method, and the rest of the process is the same as that of example 2, as follows: the tailings of the second stage strong magnetic are self-flowed into the third stage strong magnetic, the tailings of the third stage strong magnetic are pumped to the shaking table for selection by the slurry pump, the tailings of the shaking table are directly discarded, and the second and third stage strong magnetic concentrate and the shaking table concentrate are combined as a recovered iron concentrate with an iron grade of 38.50%. According to the sales requirements of iron concentrate with an iron grade of more than 64% and a silicon dioxide content of less than 6.00%, the recovered iron concentrate pipeline gate valve can be controlled to be appropriately mixed into the recovered iron concentrate into the iron concentrate (the recovered iron concentrate pipeline gate valve can be controlled to be appropriately mixed into the recovered iron concentrate into the iron concentrate Figure 3 ) of the iron concentrate; in 2023, 5.24 million tons of recovered iron concentrate with an iron grade of 38.50% and 779 million tons of washing machine concentrate with an iron grade of 66.90% are mixed into 831.4 million tons of iron concentrate with an iron grade of 65.11% and a silicon dioxide content of 5.76% to be sold to internal units, and 7.5 million tons of recovered iron concentrate with an iron grade of 38.50% are produced for external sales.

[0040] The difference between the beneficiation process of the present application and the original beneficiation process is shown in Table 1.

[0041] Table 1 Comparison of original beneficiation process and present beneficiation process

[0042]

[0043] Compared with the original beneficiation technology, the beneficiation method of the present application has the following advantages:

[0044] (1) Since the semi-autogenous mill sand return discarding method is adopted, the waste rock yield of the semi-autogenous mill sand return discarding is more than 1.5%, the iron grade of the discarded waste rock is less than 12.50%, and the annual output is more than 60,000 tons; the equipment load and energy consumption of the subsequent processes are effectively reduced, and the production cost is reduced by 168 million yuan according to the process cost of 28 yuan / t of subsequent grinding, beneficiation, and tailings thickening and conveying, i.e. 60,000 tons / a x 28 yuan / t = 168 million yuan; at the same time, the income of discarded waste rock is increased by 18 million yuan, i.e. 60,000 tons / a x 3 yuan / t = 18 million yuan, and the total economic benefit is 186 million yuan.

[0045] (2) The iron series adopts a three-tower mill grinding and classification system to process magnetite, and the grinding fineness is improved from 80%-83% of -325 mesh to 86%-90% of -325 mesh, and the magnetite concentrate grade is improved from 64.00% to more than 66.00%.

[0046] (3) The tailings of the elutriation machine have an iron grade of 15%-25%, and two full-disk tailings recovery machines are used to process the tailings of the elutriation machine in a one-roughing-one-scavenging process. The concentrates of the two full-disk tailings recovery machines are returned to the three-stage grinding-classification-separation system for regrinding and reseparation. The tailings of the full-disk tailings recovery machines have an iron grade of less than 11% and can be directly discharged.

[0047] (4) After the addition of a double-deck shaking table to process the high-intensity magnetic tailings, the shaking table concentrate yield is 0.8%, and the shaking table concentrate with an iron grade of more than 35% is increased by 32,000 tons per year.

[0048] (5) After the addition of a full-disk tailings recovery machine to recover magnetic iron before the second-stage high-intensity magnetic separation, there is no magnetic agglomeration and plugging on the shaking table bed surface, and there is no magnetic iron in the total tailings.

[0049] (6) After the improvement of the iron series production process according to the above measures, the production process is adjusted in a timely manner according to the raw ore in daily production. While ensuring that the iron concentrate (mainly hematite, also known as "hematite concentrate") has an iron grade of more than 35%, the tailings iron grade is reduced from below 11.00% to below 10.00%. According to the annual processing of 4 million tons of iron ore in the iron series, 88,000 tons of iron concentrate with an iron grade of 35% can be recovered per year, 60,000 tons of waste rock can be increased, the raw ore processing cost can be reduced by 1.68 million yuan, the sales of waste rock and recovered iron concentrate without tax can be increased by 12.6037 million yuan, and the profit can be increased by 6.4665 million yuan.

Claims

1. A beneficiation method for stabilizing production indexes when multiple different properties of iron ore are beneficiated simultaneously, characterized by, The following steps are implemented: 1) The iron ore is ground by a semi-autogenous mill and then fed to a GK screen. The oversize material is discarded by a magnetic drum, and the discarded concentrate is returned to the semi-autogenous mill for regrinding; 2) The undersize material from the GK screen is fed to a cyclone group for classification. The cyclone underflow is fed to a ball mill for regrinding, and the ball mill product is fed to the cyclone group for classification. The overflow from the cyclone with a fineness of 73-78% passing a 200 mesh sieve is fed to a first-stage low-intensity magnetic separator; 3) The tailings from the first-stage low-intensity magnetic separator are fed to a first-stage desliming screen. The undersize material from the desliming screen is fed to a first-stage high-intensity magnetic separator, and the oversize material from the desliming screen and the concentrate from the first-stage low-intensity magnetic separator are fed to a tower mill grinding and classification system. The concentrate from the first-stage low-intensity magnetic separator is subjected to tower mill grinding, low-intensity magnetic separation, and full-automatic elutriation to obtain a magnetite concentrate. The concentrate from the first-stage high-intensity magnetic separator is subjected to high-intensity magnetic separation and gravity separation to obtain a hematite concentrate; 4) Two full-disk tailings recovery machines are used to recover magnetite from the tailings of the elutriator and feed the recovered magnetite to the tower mill grinding and classification system and subsequent processes for regrinding and reseparation; In step 3), the slurry from the grinding of the oversize material from the desliming screen and the concentrate from the first-stage low-intensity magnetic separator is fed to a Φ350*12 cyclone group for classification. The overflow from the cyclone group with a fineness of 86-90% passing a 325 mesh sieve is fed to a second-stage low-intensity magnetic separator. The underflow from the cyclone group is returned to the tower mill for regrinding. The tailings from the second-stage low-intensity magnetic separator are fed to a 6400m² inclined plate thickener. The concentrate from the second-stage low-intensity magnetic separator is fed to a third-stage low-intensity magnetic separator. The tailings from the third-stage low-intensity magnetic separator are fed to the tower mill grinding and classification system for regrinding. The concentrate from the third-stage low-intensity magnetic separator is fed to the elutriator. The concentrate from the elutriator is an iron concentrate with a grade of 66% or higher, i.e., a magnetite concentrate. The tailings from the elutriator are fed to a 1# full-disk tailings recovery machine; The concentrate from the first-stage high-intensity magnetic separator is fed to a 6400m² inclined plate thickener. The overflow from the inclined plate is recycled water. The underflow from the inclined plate is fed to a full-disk tailings recovery machine. The concentrate from the full-disk tailings recovery machine is fed to the tower mill grinding and classification system and subsequent processes for regrinding and reseparation. The tailings from the full-disk tailings recovery machine that do not contain magnetic iron are fed to a second-stage desliming screen. The oversize material from the desliming screen is fed to the tower mill grinding and classification system. The undersize material from the desliming screen is fed to a second-stage high-intensity magnetic separator. The concentrate from the second-stage high-intensity magnetic separator is fed to a third-stage high-intensity magnetic separator for reseparation. The tailings from the second-stage high-intensity magnetic separator are fed to a ditch for discarding. The concentrate from the third-stage high-intensity magnetic separator and the concentrate from the shaking table are combined to obtain a recovered iron concentrate, i.e., a hematite concentrate. According to the sales requirements of an iron concentrate with a grade of 64% or higher and a silicon dioxide content of 6.00% or lower, a recovered iron concentrate pipe gate valve can be controlled to appropriately mix the recovered iron concentrate into the iron concentrate.

2. The beneficiation method according to claim 1, characterized in that, The tailings from the 1# full-disk tailings recovery machine are fed to a 2# full-disk tailings recovery machine for sweeping. The concentrates from the 1# and 2# full-disk tailings recovery machines are returned to the tower mill grinding and classification system for regrinding. The tailings from the 2# full-disk tailings recovery machine are fed to a ditch for discarding.

3. The method of claim 1, wherein, The magnetic iron is recovered by a full-disk tailings recovery machine before the second-stage high-intensity magnetic separator.

4. The method of claim 1, wherein, In step 3), when the proportion of underground ore is more than 50%, the first-stage high-intensity magnetic separation of the concentrate uses a one-stage roughing, one-stage cleaning, and one-stage sweeping process. When the proportion of underground ore is less than 50%, the first-stage high-intensity magnetic separation uses a one-stage roughing and two-stage cleaning process.

5. The method of claim 1, wherein, In step 1), the waste rock selected by throwing is transported to a waste rock storage by vehicles and sold to the outside.

6. The method of claim 1, wherein, In step 1), the semi-autogenous mill is of MZS8848 type.

7. The method of claim 1, wherein, In step 2), the cyclone group is of Φ660*12 cyclone group, and the ball mill is of MQY6095 ball mill.

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