A one-stage non-desliming dense medium two-stage two-gradation system

Abstract

The application relates to the heavy medium ore dressing technical field, in particular to a one-stage non-desliming heavy medium two-stage two-selection system, which comprises a grading desliming unit, a heavy medium one-stage concentrate collecting unit, a heavy medium two-stage waste throwing unit and a medium circulating unit. The material bin discharge port of the heavy medium separation system is connected with a grading screen, the grading screen divides the selected material into two particle size products of qualified particle size and fine particle size, the qualified particle size enters the heavy medium one-stage concentrate collecting unit to obtain qualified concentrate and non-desliming tailings, the non-desliming tailings enter the heavy medium two-stage waste throwing unit to obtain heavy medium middlings and final tailings. The medium circulating unit guarantees the stability of the water quantity and medium quantity in the heavy medium two-stage two-selection system. The application has the advantages of less equipment quantity, small equipment investment, more reasonable and efficient equipment arrangement, small land occupation and simple operation of the heavy medium separation system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heavy medium separation, in particular to a one-stage non-desliming heavy medium two-stage two-selection system. BACKGROUND

[0002] It is known that, with the development of mineral resources, the increasing impoverishment of ores and the increasing requirements for environmental protection, pre-concentration technology is particularly important in the green and sustainable development of the mining industry. The heavy medium separation technology has the advantages of high separation accuracy, a relatively large range of separation particle size, high efficiency in discarding waste rock in pre-concentration, no sewage in the separation process, etc. It is one of the green, environmentally friendly and efficient pre-concentration methods, and its application in non-ferrous metal and non-metal ore dressing is gradually increasing.

[0003] For ores with good dissociation degree, heavy medium separation technology can dispose a large amount of qualified tailings at one time. However, for ores with special market demand or low grade and difficult to separate, two separations may be needed to obtain good separation indexes. For example, spodumene, fluorite and lead-zinc ores currently need two sets of heavy medium systems in series for two separations to obtain high-grade concentrates and qualified tailings. The investment cost of the two sets of heavy medium systems is large, and the equipment arrangement is scattered and inconvenient for unified management. SUMMARY

[0004] The purpose of the present application is to solve the above-mentioned problems of the prior art and provide a one-stage non-desliming heavy medium two-stage two-selection system with fewer devices, small investment and more reasonable and efficient device arrangement.

[0005] The technical solution adopted by the present application to solve the technical problems is:

[0006] A one-stage non-desliming heavy medium two-stage two-selection system, characterized in that the system comprises a classification desliming unit, a heavy medium first-stage concentrate collecting unit, a heavy medium second-stage waste discarding unit and a medium recovery unit. The classification desliming unit outputs qualified material and fine particle material at its outlet. The qualified material is separated by the heavy medium first-stage concentrate collecting unit to obtain qualified concentrate and non-deslimed tailings. The non-deslimed tailings are separated by the heavy medium second-stage waste discarding unit to obtain heavy medium middlings and final tailings. The undersize outlets of the heavy medium first-stage concentrate collecting unit and the heavy medium second-stage waste discarding unit are connected to the medium recovery unit, which ensures the stability of the water quantity and medium quantity inside the heavy medium two-stage two-selection system.

[0007] The grading desliming unit comprises a feeding tank, a grading screen, a discharge tank and two under-screen chutes, the outlet of the feeding tank is connected with the inlet of the grading screen, the over-screen outlet of the grading screen is connected with the inlet of the discharge tank, the discharge tank is connected with the heavy medium one-stage concentrate recovery unit through one of the under-screen chutes, the fine particle level material output from the under-screen outlet of the grading screen enters the other under-screen chute, and the other under-screen chute is fed into a subsequent fine particle level material processing unit through a pipeline.

[0008] The heavy medium one-stage concentrate recovery unit comprises a first heavy medium medium mixing barrel, a first heavy medium cyclone, a first concentrate fixed screen and a first concentrate medium removal screen, the inlet of the first heavy medium medium mixing barrel is connected with the discharge tank in the grading desliming unit, the outlet of the first heavy medium medium mixing barrel is connected with the inlet of the first heavy medium cyclone through a first slurry pump, the underflow outlet of the first heavy medium cyclone is connected with the first concentrate fixed screen through a pipeline, the over-screen product outlet of the first concentrate fixed screen is connected with the first concentrate medium removal screen, and the overflow outlet of the first heavy medium cyclone is connected with a heavy medium two-stage waste throwing unit through a pipeline.

[0009] The heavy medium two-stage waste throwing unit comprises a second heavy medium medium mixing barrel, a second heavy medium cyclone, a second concentrate fixed screen, a second concentrate medium removal screen, a second tailing fixed screen and a second tailing medium removal screen, the inlet of the second heavy medium medium mixing barrel is connected with the overflow outlet of the first heavy medium cyclone and the under-screen outlet of the first concentrate fixed screen, the outlet of the second heavy medium medium mixing barrel is connected with the inlet of the second heavy medium cyclone through a second slurry pump, the overflow outlet and the underflow outlet of the second heavy medium cyclone are connected with the second tailing fixed screen and the second concentrate fixed screen through pipelines respectively, the over-screen product outlets of the second tailing fixed screen and the second concentrate fixed screen are connected with the second tailing medium removal screen and the second concentrate medium removal screen respectively, and the under-screen product outlets of the second concentrate fixed screen and the second tailing fixed screen are connected with the first heavy medium medium mixing barrel.

[0010] The medium recovery unit comprises a dilute medium barrel and a magnetic separator, the under-screen product outlets of the first concentrate medium removal screen, the second concentrate medium removal screen and the second tailing medium removal screen are connected with the dilute medium barrel, and the outlet of the dilute medium barrel is connected with the inlet of the magnetic separator through a third slurry pump.

[0011] The magnetic product outlet of the magnetic separator is connected with the first heavy medium medium mixing barrel through a pipeline, and the non-magnetic product outlet of the magnetic separator is connected with a backwater pool through a pipeline.

[0012] The heavy medium in the first heavy medium medium mixing barrel (3) is ferrosilicon powder, the content of magnetic substances of the ferrosilicon powder is greater than or equal to 95%, and the fineness of-325 mesh is greater than or equal to 90%.

[0013] The density of the heavy medium suspension in the first heavy medium mixing barrel (3) is 2.0-3.2 g / cm³.

[0014] The pressure of the first slurry pump is 0.1-0.25 Mpa, the pressure of the second slurry pump is 0.1-0.25 Mpa, and the pressure of the third slurry pump is 0.1-0.15 Mpa.

[0015] Beneficial effects:

[0016] (1) The heavy medium one-stage collection system can complete the separation of target minerals, and the products meet the requirements of sales or smelting grade, and the heavy separation concentrate produced can be directly sold, and the capital flow is quickly completed;

[0017] (2) The heavy medium two-stage waste throwing system can complete the separation of gangue minerals, and can directly throw tailings with a lower grade than the industry standard. First, it reduces the amount of ore entering the grinding and floating process, reducing production costs, and second, the heavy separation tailings produced can be stacked or directly sold, quickly completing the capital flow.

[0018] (3) The one-stage non-dense medium process can reduce the tailings fixed screen and tailings medium separation screen in the heavy medium one-stage collection system, thereby reducing the equipment investment cost and reducing the land area.

[0019] (4) The first concentrate fixed screen under the mixed medium enters the second heavy medium mixing barrel, ensuring that the heavy medium suspension entering the heavy medium two-stage waste throwing unit has a higher density than the two-stage separation density, without the need to configure the heavy medium suspension again, and ensuring the stability of the heavy medium two-stage waste throwing system;

[0020] (5) The second concentrate fixed screen and the second tailings fixed screen return the mixed medium under the screen to the first heavy medium mixing barrel, ensuring that the amount of qualified medium of the heavy medium one-stage collection unit meets the actual production demand, thereby ensuring the stable operation of the heavy medium one-stage collection system;

[0021] (6) The second concentrate fixed screen and the second tailings fixed screen return the mixed medium under the screen to the first heavy medium mixing barrel, ensuring that the amount of qualified medium of the heavy medium one-stage collection unit meets the actual production demand, thereby ensuring the stable operation of the heavy medium one-stage collection system;

[0022] (7) The dilute medium under the first concentrate medium separation screen, the second concentrate medium separation screen, and the second tailings medium separation screen is all collected in the dilute medium barrel, and the medium is recovered by the magnetic separator, which can reduce the number of dilute medium barrels and dilute medium pumps in the heavy medium two-stage two-selection system, thereby reducing the equipment investment cost and reducing the land area;

[0023] (8) The dilute medium under the first concentrate medium removal screen, the second concentrate medium removal screen and the second tailings medium removal screen is all collected into the dilute medium barrel, and the medium recovery is uniformly conducted by the magnetic separator, so that the stability of the dilute medium in the medium recovery process is ensured, and in addition, the arrangement of the medium recovery equipment is more reasonable and efficient.

[0024] (9) The dilute medium under the first concentrate medium removal screen, the second concentrate medium removal screen and the second tailings medium removal screen is all collected into the dilute medium barrel, and the medium recovery is uniformly conducted by the magnetic separator, so that the stability of the dilute medium in the medium recovery process is ensured, and in addition, the arrangement of the medium recovery equipment is more reasonable and efficient.

[0025] (9) The dilute medium under the first concentrate medium removal screen, the second concentrate medium removal screen and the second tailings medium removal screen is all collected into the dilute medium barrel, and the medium recovery is uniformly conducted by the magnetic separator, so that the stability of the dilute medium in the medium recovery process is ensured, and in addition, the arrangement of the medium recovery equipment is more reasonable and efficient.

[0026] (11) The one-stage non-medium removal process optimizes the originally independent heavy medium two-stage two-selection separation system into a more scientific and perfect heavy medium separation system, the heavy medium separation system is simple to operate, and the personnel configuration of the heavy medium separation workshop is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural schematic diagram of the present application. DETAILED DESCRIPTION

[0028] The present application is further described below in combination with the drawings:

[0029] As shown in the drawings, a one-stage non-medium removal heavy medium two-stage two-selection system, characterized in that the system comprises a classified desliming unit, a heavy medium first-stage concentrate collection unit, a heavy medium second-stage discard unit and a medium recovery unit, the outlet of the classified desliming unit outputs qualified material and fine particle material, the qualified material is separated by the heavy medium first-stage concentrate collection unit to obtain qualified concentrate and non-medium removal tailings, the non-medium removal tailings are separated by the heavy medium second-stage discard unit to obtain heavy medium concentrate and final tailings, the under-screen outlets of the heavy medium first-stage concentrate collection unit and the heavy medium second-stage discard unit are connected with the medium recovery unit, and the medium recovery unit ensures the stability of the water quantity and medium quantity in the heavy medium two-stage two-selection system.

[0030] Further, the classified desliming unit comprises a feeding tank 1, a classified screen 2, a discharge tank and two under-screen chute, the outlet of the feeding tank 1 is connected with the inlet of the classified screen 2, the under-screen outlet of the classified screen 2 is connected with the inlet of the discharge tank, the discharge tank is connected with the heavy medium first-stage concentrate collection unit through one of the under-screen chute, and the fine particle material output by the under-screen outlet of the classified screen 2 enters the other under-screen chute, and the other under-screen chute is connected with the subsequent fine particle material processing unit through a pipeline.

[0031] Further, the heavy medium one-stage concentrate collecting unit comprises a first heavy medium mixing barrel 3, a first heavy medium cyclone 4, a first concentrate fixed screen 5, and a first concentrate medium draining screen 6. The inlet of the first heavy medium mixing barrel 3 is connected with the discharge chute in the grading desliming unit, and the outlet of the first heavy medium mixing barrel 3 is connected with the inlet of the first heavy medium cyclone 4 through a first slurry pump. The underflow outlet of the first heavy medium cyclone 4 is connected with the first concentrate fixed screen 5 through a pipeline, the oversize product outlet of the first concentrate fixed screen 5 is connected with the first concentrate medium draining screen 6, and the overflow outlet of the first heavy medium cyclone 4 is connected with the heavy medium two-stage waste throwing unit through a pipeline.

[0032] Further, the heavy medium two-stage waste throwing unit comprises a second heavy medium mixing barrel 7, a second heavy medium cyclone 8, a second concentrate fixed screen 9, a second concentrate medium draining screen 10, a second tailing fixed screen 11, and a second tailing medium draining screen 12. The inlet of the second heavy medium mixing barrel 7 is connected with the overflow outlet of the first heavy medium cyclone 4 and the undersize product outlet of the first concentrate fixed screen 5, and the outlet of the second heavy medium mixing barrel 7 is connected with the inlet of the second heavy medium cyclone 8 through a second slurry pump. The overflow outlet and the underflow outlet of the second heavy medium cyclone 8 are connected with the second tailing fixed screen 11 and the second concentrate fixed screen 9 through pipelines respectively, the oversize product outlets of the second tailing fixed screen 11 and the second concentrate fixed screen 9 are connected with the second tailing medium draining screen 12 and the second concentrate medium draining screen 10 respectively, and the undersize product outlets of the second concentrate fixed screen 9 and the second tailing fixed screen 11 are connected with the first heavy medium mixing barrel 3.

[0033] Further, the medium recycling unit comprises a dilute medium barrel 13 and a magnetic separator 14. The undersize product outlets of the first concentrate medium draining screen 6, the second concentrate medium draining screen 10, and the second tailing medium draining screen 12 are connected with the dilute medium barrel 13, and the outlet of the dilute medium barrel 13 is connected with the inlet of the magnetic separator 14 through a third slurry pump.

[0034] Further, the magnetic product outlet of the magnetic separator 14 is connected with the first heavy medium mixing barrel 3 through a pipeline, and the non-magnetic product outlet of the magnetic separator 14 is connected with a backwater pool through a pipeline.

[0035] Further, the heavy medium in the first heavy medium mixing barrel 3 is silicon-iron powder, and the silicon-iron powder has a magnetic substance content of ≥95% and a fineness of -325 mesh ≥90%.

[0036] Further, the density of the heavy medium suspension in the first heavy medium mixing barrel 3 is 2.0-3.2 g / cm³.

[0037] Furthermore, the pressure of the first slurry pump is 0.1 MPa-0.25 MPa, and the pressure of the second slurry pump is 0.1 MPa-0.25 MPa. The heavy medium suspension and ore are fed into the two-product heavy medium hydrocyclone at a pressure of 0.1 MPa to 0.25 MPa by the slurry pumps, and are separated under the action of centrifugal force. The underflow product of the two-product heavy medium hydrocyclone is further processed to become heavy medium concentrate, and the overflow product is further processed to become waste rock. The pressure of the third slurry pump is 0.1 MPa-0.15 MPa.

[0038] In the above scheme: the outlet of the undersize product of the first concentrate fixed screen 5 is connected to the second heavy medium mixing tank 7. The purpose is to ensure that the density of the heavy medium suspension entering the second stage waste disposal unit is higher than the second stage separation density, thereby ensuring the stable operation of the second stage waste disposal system. The outlet of the undersize product of the second concentrate fixed screen 9 and the second tailings fixed screen 11 is connected to the first heavy medium mixing tank 3. The purpose is to return the qualified medium entering the second stage waste disposal unit to the first stage heavy medium collection and purification unit, thereby ensuring the stable operation of the first stage heavy medium collection and purification system. The system operates under constant conditions; the undersize product outlets of the first concentrate desliming screen 6, the second concentrate desliming screen 10, and the second tailings desliming screen 12 are connected to the magnetic separator 14; the magnetic product outlet of the magnetic separator 14 is connected to the first heavy medium mixing tank 3 via a pipeline, and the non-magnetic product outlet of the magnetic separator 14 is connected to the return water tank via a pipeline. The purpose is to recover the dilute medium generated by the two-stage heavy medium separation system without desliming, and to discharge excess water from the system, thereby ensuring the stability of the medium and water volume in the two-stage heavy medium separation system.

[0039] Example 1:

[0040] A spodumene mine in Xinjiang has a raw ore Li₂O grade of 1.50% and a particle size of -6mm. A two-stage, two-selection system with a single-stage heavy media separation process without desaturation is used to separate the spodumene. The specific steps are as follows: First, the raw ore is fed into a classifying screen 2 via a feed trough 1. Products smaller than -6mm are screened. After screening by the classifying screen 2, particles of 0.5-6mm and smaller than -0.5mm are obtained. The 0.5-6mm particle size product is used as feed to the heavy media separation system, while the -0.5mm particle size product is fed into subsequent operations.

[0041] In the first heavy medium mixing tank 3, ferrosilicon powder (magnetic content ≥95%, fineness -325 mesh ≥90%) is mixed with water to form a heavy medium suspension with a density of 2.40 g / cm3. This suspension is then mixed evenly with the 0.5-6 mm particle size raw ore on the grading screen 2 and pumped into the first heavy medium hydrocyclone 4 for separation, yielding underflow and overflow products. The separated underflow products are then passed sequentially through the first concentrate fixed screen 5 and the first concentrate desliming screen 6. After being washed with water to remove the heavy medium, the product on the first concentrate desliming screen 6 is used to obtain the gravity concentrate with a grade of 5.50%. The recovery rate of this operation is 25%, and the overall recovery rate is 70.20%. The overflow products after separation are directly sent to the second stage heavy medium waste disposal system.

[0042] The overflow product after the first separation is fed together with the undersize medium of the first concentrate fixed screen into the second medium mixing tank 7. The density of the second medium mixing tank 7 is 2.30 g / cm3. Through the automatic water replenishment system, it is prepared into a slurry suspension with a density of 2.00 g / cm3. The slurry is then pumped into the second medium hydrocyclone 8 for separation to obtain the sand product and the overflow product. The overflow products after separation pass sequentially through the second tailings fixed screen 11 and the second tailings desliming screen 12. After being washed with water, the heavy media are removed. The oversize product of the second tailings desliming screen 12 is a low-grade gravity separation tailings, which can be directly used for backfilling or sold. The gravity separation tailings grade is 0.25%. The tailings rejection rate of this operation reaches 40%, and the tailings metal loss rate is 5.15%. The sand products after separation pass sequentially through the second concentrate fixed screen 9 and the second concentrate desliming screen 10. After being washed with water, the heavy media are removed. The oversize product of the second concentrate desliming screen 10 is a medium-grade product with a medium-grade of 0.91%.

[0043] The combined medium (density of 1.90 g / cm3) under the second tailings fixed screen 11 and the second concentrate fixed screen 9 is returned to the first heavy medium combined medium tank 3.

[0044] The undersized dilute medium (density of 1.20 g / cm3) from the first concentrate desliming screen 6, the second concentrate desliming screen 10, and the second tailings desliming screen 12 is fed into the dilute medium tank 13 and pumped by the third slurry pump to the magnetic separator 14 for medium recovery. The density of the heavy medium suspension recovered by the magnetic separator 14 is 2.85 g / cm3, which is fed into the first heavy medium combining tank 3. The magnetic tailings water is connected to the return water pool through a pipeline.

[0045] The advantages of the traditional two-stage, two-selection process for heavy media and the two-stage, two-selection system for heavy media without media removal proposed in this application are compared as follows:

[0046]

[0047] As can be seen from the above comparison, compared with the original traditional two-stage two-selection process for heavy media, the two-stage two-selection system for heavy media without media removal in this application has lower equipment investment, infrastructure investment, labor costs, and production and operation costs, and the separation index is slightly better than that of the original traditional process.

[0048] Example 2

[0049] A lead-zinc oxide mine in Yunnan Province has a Pb+Zn grade of 11.98% and a particle size of -20mm. A two-stage, two-part heavy media separation system with a single stage without descaling is used to separate the lead-zinc oxide ore. The specific steps are as follows: First, the raw ore is fed into the classifying screen 2 through the feed trough 1. Products below -20mm are screened. After screening by the classifying screen 2, particles of 0.5-20mm and particles below -0.5mm are obtained. The product with a particle size of 0.5-20mm is used as the feed for the heavy media separation system, and the product with a particle size of -0.5mm is fed into subsequent operations.

[0050] In the first heavy medium mixing tank 3, ferrosilicon powder (magnetic content ≥95%, fineness -325 mesh ≥90%) is mixed with water to form a heavy medium suspension with a density of 2.00 g / cm3. This suspension is then mixed evenly with the 0.5-20 mm particle size raw ore on the grading screen 2 and pumped into the first heavy medium hydrocyclone 4 for separation, yielding underflow and overflow products. The separated underflow products are then passed sequentially through the first concentrate fixed screen 5 and the first concentrate desliming screen 6. After being washed with water to remove the heavy medium, the product on the first concentrate desliming screen 6 is used to obtain the gravity concentrate with a grade of 17.03%. The recovery rate of this operation is 35%, and the overall recovery rate is 49.75%. The overflow products after separation are directly sent to the second stage heavy medium waste disposal system.

[0051] The overflow product after the first separation is fed together with the undersize medium of the first concentrate fixed screen into the second medium mixing tank 7. The density of the second medium mixing tank 7 is 1.95 g / cm3. Through the automatic water replenishment system, it is prepared into a slurry suspension with a density of 1.85 g / cm3. The slurry is then pumped into the second medium hydrocyclone 8 for separation to obtain the sand product and the overflow product. The overflow products after separation pass sequentially through the second tailings fixed screen 11 and the second tailings desliming screen 12. After being washed with water, the heavy media are removed. The oversize product of the second tailings desliming screen 12 is a low-grade gravity separation tailings, which can be directly used for backfilling or sold. The gravity separation tailings grade is 1.5%. The tailings rejection rate of this operation reaches 25%, and the tailings metal loss rate is 6.00%. The sand products after separation pass sequentially through the second concentrate fixed screen 99 and the second concentrate desliming screen 10. After being washed with water, the heavy media are removed. The oversize product of the second concentrate desliming screen 10 is a medium-grade product with a medium-grade of 4.25%.

[0052] The combined medium (density of 1.80 g / cm3) under the second tailings fixed screen 11 and the second concentrate fixed screen 9 is returned to the first heavy medium combined medium tank 3.

[0053] The undersized dilute medium (density of 1.20 g / cm3) from the first concentrate desliming screen 6, the second concentrate desliming screen 10, and the second tailings desliming screen 12 is fed into the dilute medium tank 13 and pumped by the third slurry pump to the magnetic separator 14 for medium recovery. The density of the heavy medium suspension recovered by the magnetic separator 14 is 2.85 g / cm3, which is fed into the first heavy medium combining tank 3. The magnetic tailings water is connected to the return water pool through a pipeline.

[0054] The advantages of the traditional two-stage, two-selection process for heavy media and the two-stage, two-selection system for heavy media without media removal proposed in this application are compared as follows:

[0055]

[0056] As can be seen from the above comparison, compared with the original traditional two-stage two-selection process for heavy media, the two-stage two-selection system for heavy media without media removal in this application has lower equipment investment, infrastructure investment, labor costs, and production and operation costs, and the separation index is slightly better than that of the original traditional process.

[0057] Example 3

[0058] A fluorite mine in Jiangxi Province has a raw ore CaF2 grade of 35% and a particle size of -30mm. A two-stage, two-separation system with heavy media separation without desaturation is used to separate the fluorite ore. The specific steps are as follows: First, the raw ore is fed into the classifying screen 2 through the feed trough 1. Products below -30mm are screened. After screening by the classifying screen 2, particles of 1-30mm and particles below -0.5mm are obtained. The product with a particle size of 1-30mm is used as the feed for the heavy media separation system, and the product with a particle size of -1mm is fed into subsequent operations.

[0059] In the first heavy medium mixing tank 3, ferrosilicon powder (magnetic content ≥95%, fineness -325 mesh ≥90%) is mixed with water to form a heavy medium suspension with a density of 2.20 g / cm3. This suspension is then mixed evenly with the 1-30 mm particle size raw ore on the grading screen 22 and pumped into the first heavy medium hydrocyclone 4 for separation, yielding underflow and overflow products. The separated underflow products are then passed sequentially through the first concentrate fixed screen 5 and the first concentrate desliming screen 6. After being washed with water to remove the heavy medium, the product on the first concentrate desliming screen 6 is used to obtain the gravity concentrate with a grade of 80%. The recovery rate of this operation is 30%, and the overall recovery rate is 68.57%. The overflow products after separation are directly sent to the second stage heavy medium waste disposal system.

[0060] The overflow product after the first separation is fed together with the undersize medium of the first concentrate fixed screen into the second medium mixing tank 7. The density of the second medium mixing tank 7 is 2.12 g / cm3. Through the automatic water replenishment system, it is prepared into a slurry suspension with a density of 2.00 g / cm3. The slurry is then pumped into the second medium hydrocyclone 8 for separation to obtain the sand product and the overflow product. The overflow products after separation pass sequentially through the second tailings fixed screen 11 and the second tailings desliming screen 12. After being washed with water, the heavy media are removed. The oversize product of the second tailings desliming screen 12 is a low-grade gravity separation tailings, which can be directly used for backfilling or sold. The gravity separation tailings grade is 5.5%. The tailings rejection rate of this operation reaches 35%, and the tailings metal loss rate is 6.25%. The sand products after separation pass sequentially through the second concentrate fixed screen 9 and the second concentrate desliming screen 10. After being washed with water, the heavy media are removed. The oversize product of the second concentrate desliming screen 10 is a medium-grade product with a medium-grade of 15%.

[0061] The combined medium (density of 1.90 g / cm3) under the second tailings fixed screen 11 and the second concentrate fixed screen 9 is returned to the first heavy medium combined medium tank 3.

[0062] The undersized dilute medium (density of 1.20 g / cm3) from the first concentrate desliming screen 6, the second concentrate desliming screen 10, and the second tailings desliming screen 12 is fed into the dilute medium tank 13 and pumped by the third slurry pump to the magnetic separator 14 for medium recovery. The density of the heavy medium suspension recovered by the magnetic separator 14 is 2.85 g / cm3, which is fed into the first heavy medium combining tank 3. The magnetic tailings water is connected to the return water pool through a pipeline.

[0063] The advantages of the traditional two-stage, two-selection process for heavy media and the two-stage, two-selection system for heavy media without media removal proposed in this application are compared as follows:

[0064]

[0065] As can be seen from the above comparison, compared with the original traditional two-stage two-selection process for heavy media, the two-stage two-selection system for heavy media without media removal in this application has lower equipment investment, infrastructure investment, labor costs, and production and operation costs, and the separation index is slightly better than that of the original traditional process.

Claims

1. A one-stage non-deslimed dense medium two-stage two-product system, characterized in that The system comprises a grading desliming unit, a heavy medium one-stage concentrate collecting unit, a heavy medium two-stage waste throwing unit and a medium recovery unit, the grading desliming unit outputs qualified grade material and fine grade material, the qualified grade material is separated by the heavy medium one-stage concentrate collecting unit to obtain qualified concentrate and un-deslimed tailings, the un-deslimed tailings are separated by the heavy medium two-stage waste throwing unit to obtain heavy medium middlings and final tailings, the undersize outlets of the heavy medium one-stage concentrate collecting unit and the heavy medium two-stage waste throwing unit are connected with the medium recovery unit, the medium recovery unit ensures the stability of water quantity and medium quantity in the heavy medium two-stage two-selection system, the grading desliming unit comprises a feeding tank, a grading screen, a discharging tank and two undersize chute, the outlet of the feeding tank is connected with the inlet of the grading screen, the oversize outlet of the grading screen is connected with the inlet of the discharging tank, the discharging tank is connected with the heavy medium one-stage concentrate collecting unit through one of the undersize chute, the fine grade material output by the undersize outlet of the grading screen enters the other undersize chute, the other undersize chute is connected with a subsequent fine grade material processing unit through a pipeline, the heavy medium one-stage concentrate collecting unit comprises a first heavy medium medium mixing barrel, a first heavy medium cyclone, a first concentrate fixed screen and a first concentrate desliming screen, the inlet of the first heavy medium medium mixing barrel is connected with the discharging tank in the grading desliming unit, the outlet of the first heavy medium medium mixing barrel is connected with the inlet of the first heavy medium cyclone through a first slurry pump, the underflow outlet of the first heavy medium cyclone is connected with the first concentrate fixed screen through a pipeline, the oversize product outlet of the first concentrate fixed screen is connected with the first concentrate desliming screen, the overflow outlet of the first heavy medium cyclone is connected with the heavy medium two-stage waste throwing unit through a pipeline, the heavy medium two-stage waste throwing unit comprises a second heavy medium medium mixing barrel, a second heavy medium cyclone, a second concentrate fixed screen, a second concentrate desliming screen, a second tailings fixed screen and a second tailings desliming screen, the inlet of the second heavy medium medium mixing barrel is connected with the overflow outlet of the first heavy medium cyclone and the undersize outlet of the first concentrate fixed screen, the outlet of the second heavy medium medium mixing barrel is connected with the inlet of the second heavy medium cyclone through a second slurry pump, the overflow outlet and the underflow outlet of the second heavy medium cyclone are connected with the second tailings fixed screen and the second concentrate fixed screen through pipelines respectively, the oversize product outlets of the second tailings fixed screen and the second concentrate fixed screen are connected with the second tailings desliming screen and the second concentrate desliming screen respectively, the undersize product outlets of the second concentrate fixed screen and the second tailings fixed screen are connected with the first heavy medium medium mixing barrel.

2. A one-stage non-disintegrating dense medium two-stage two-product system according to claim 1, characterized in that The undersize product outlets of the first concentrate desliming screen, the second concentrate desliming screen and the second tailings desliming screen are connected with a dilute medium barrel, the outlet of the dilute medium barrel is connected with the inlet of a magnetic separator through a third slurry pump.

3. A one-stage non-disintegrating dense medium two-stage two-product system according to claim 2, characterized in that The magnetic product outlet of the magnetic separator is connected with the first heavy medium medium mixing barrel through a pipeline, the non-magnetic product outlet of the magnetic separator is connected with a backwater pool through a pipeline.

4. A one-stage non-disintegrating dense medium two-stage two-product system according to claim 1, characterized in that The heavy medium in the first heavy medium medium mixing barrel (3) is silicon iron powder, the magnetic substance content of the silicon iron powder is greater than or equal to 95%, and the fineness of-325 mesh is greater than or equal to 90%.

5. A one-stage non-disintegrating dense medium two-stage two-product system according to claim 1, characterized in that The density of the heavy medium suspension in the first heavy medium mixed medium barrel (3) is 2.0-3.2 g / cm³.

6. A one-stage non-disintegrating dense medium two-stage two-product system according to claim 2, characterized in that The pressure of the first slurry pump is 0.1-0.25 MPa, the pressure of the second slurry pump is 0.1-0.25 MPa, and the pressure of the third slurry pump is 0.1-0.15 MPa.

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