A method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ores

Abstract

This invention provides a method for pre-enriching lead, zinc, and silver in low-grade lead-zinc-silver ore, belonging to the field of mineral processing technology. The invention first crushes the raw low-grade lead-zinc-silver ore to be processed, then performs two screening operations using standard sieves of different apertures to obtain oversize product II and undersize product II. A spiral chute is used to separate the undersize product II, and a heavy media separator is used to separate the oversize product II, finally yielding lead-zinc-silver rough concentrate I, lead-zinc-silver rough concentrate II, and tailings. The method provided by this invention achieves pre-enrichment of lead, zinc, and silver in low-grade lead-zinc-silver ore, obtaining higher-grade lead-zinc-silver ore for the next mineral processing step. This simplifies the mineral processing process and significantly reduces its cost; the heavy media is recovered, reducing production costs; and the resulting tailings contain no mineral processing reagents and can be directly used as backfill material for mine goafs or sold as sand and gravel, effectively reducing production costs or generating economic benefits.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and in particular to a method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ore. Background Technology

[0002] The processing of low-grade lead-zinc-silver ores is difficult, costly, and inefficient, making it a pressing problem in the industry. Traditional beneficiation methods mainly rely on flotation and gravity separation, but their effectiveness in processing low-grade ores is less than ideal. While flotation can effectively separate minerals, it consumes large amounts of reagents, causes severe environmental pollution, and has high processing costs. Gravity separation, as an environmentally friendly physical beneficiation method, has advantages such as low cost and simple process, but its effectiveness for low-grade ores is limited. In summary, low-grade lead-zinc-silver ores urgently require efficient and environmentally friendly pre-enrichment technologies to improve ore processing efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ore. The method provided by this invention achieves efficient enrichment of lead, zinc and silver in low-grade lead-zinc-silver ore and reduces the content of associated gangue in the ore, providing high-quality feed ore for subsequent beneficiation processes. It eliminates the need to beneficiate surrounding rocks and waste rock, reduces grinding and beneficiation consumption, lowers costs, and is environmentally friendly.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for pre-enriching lead, zinc, and silver in low-grade lead-zinc-silver ore, comprising the following steps:

[0006] S1. The low-grade lead-zinc-silver ore to be processed is subjected to crushing and primary screening operations in sequence to obtain oversize product I and undersize product I.

[0007] The oversize product I is returned to the crushing operation for recycling.

[0008] S2. Perform a secondary sieving operation on the undersize product I in step S1 to obtain the oversize product II and the undersize product II;

[0009] S3. The oversize product II obtained in step S2 is subjected to heavy medium separation to obtain overflow product and underflow product;

[0010] The undersize product II obtained in step S2 is subjected to spiral chute separation to obtain lead-zinc-silver rough concentrate II and tailings II.

[0011] S4. Perform demediuming operations on the overflow product and underflow product obtained in step S3 to obtain lead-zinc-silver rough concentrate I, tailings I and heavy medium;

[0012] The heavy medium is recycled and reused.

[0013] Preferably, the aperture of the screen used in the primary screening operation in step S1 is 2-4 mm.

[0014] Preferably, the aperture of the screen used in the secondary screening operation in step S2 is 0.3 to 0.7 mm.

[0015] Preferably, the aperture of the screen used in the secondary screening operation in step S2 is 0.4 to 0.6 mm.

[0016] Preferably, the equipment used for heavy medium separation in step S3 is a heavy medium cyclone separator; the pressure of the heavy medium cyclone separator is 0.10 to 0.20 MPa.

[0017] Preferably, the heavy medium suspension used in the heavy medium separation operation in step S3 is prepared using ferrosilicon powder as the heavy medium; the density of the heavy medium suspension is 1.90–2.30 g / cm³. 3 .

[0018] Preferably, the density of the ferrosilicon powder is 6.9 g / cm³. 3 The particle size of the ferrosilicon powder is 0.065 to 0.08 mm.

[0019] Preferably, the particle size of the ferrosilicon powder is 0.070 to 0.078 mm.

[0020] Preferably, the equipment used in the desliming operation in step S4 is a desliming screen and a strong magnetic permanent magnet drum separator.

[0021] Preferably, the slurry concentration in the spiral chute separation operation in step S3 is 20% to 40%; the spiral chute is a Φ1200 type spiral chute.

[0022] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0023] 1. Improved recovery rate: This invention, through gravity pre-enrichment, can significantly improve the grade of lead, zinc, and silver in the beneficiation process, thereby increasing the metal recovery rate of low-grade ores and improving the economic benefits of mineral processing.

[0024] 2. Reduced costs: Due to the use of gravity separation technology, a large amount of gangue minerals are removed in the early stage, which reduces the workload of the mineral processing process, thereby reducing energy consumption and reagent consumption in mineral processing production and saving costs;

[0025] 3. Simplified process: The method provided by this invention provides high-quality feed ore for the next mineral processing step, which simplifies and makes the subsequent mineral processing process easier to control, and reduces the high requirements for subsequent process equipment;

[0026] 4. Environmentally friendly: This invention utilizes gravity pre-concentration without the use of chemical reagents, and can reduce the amount of reagents used in subsequent mineral processing, which is more in line with the requirements of modern green mine construction;

[0027] 5. Improve resource utilization: By pre-enriching low-grade ores, difficult-to-process ore resources can be effectively utilized, and resource potential can be fully tapped, which has significant economic and social benefits.

[0028] In summary, the method for pre-enriching lead-zinc-silver ore in low-grade lead-zinc-silver ore provided by this invention has significant advantages in processing low-grade lead-zinc-silver ore, enabling the economical and efficient utilization of low-grade ore, solving problems such as difficult beneficiation, high beneficiation costs, and complex beneficiation processes in low-grade lead-zinc-silver ore, and providing a new approach for the efficient development of mineral resources. Attached Figure Description

[0029] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention. Detailed Implementation

[0030] This invention provides a method for pre-enriching lead, zinc, and silver in low-grade lead-zinc-silver ore, comprising the following steps:

[0031] S1. The low-grade lead-zinc-silver ore to be processed is subjected to crushing and primary screening operations in sequence to obtain oversize product I and undersize product I.

[0032] The oversize product I is returned to the crushing operation for recycling.

[0033] S2. Perform a secondary sieving operation on the undersize product I in step S1 to obtain the oversize product II and the undersize product II;

[0034] S3. The oversize product II obtained in step S2 is subjected to heavy medium separation to obtain overflow product and underflow product;

[0035] The undersize product II obtained in step S2 is subjected to spiral chute separation to obtain lead-zinc-silver rough concentrate II and tailings II.

[0036] S4. Perform demediuming operations on the overflow product and underflow product obtained in step S3 to obtain lead-zinc-silver rough concentrate I, tailings I and heavy medium;

[0037] The heavy medium is recycled and reused.

[0038] Unless otherwise specified, all raw materials used in this invention are commercially available products in the art.

[0039] This invention involves sequentially crushing and primary screening low-grade lead-zinc-silver ore to be processed, yielding oversize product I and undersize product I.

[0040] In this invention, the aperture of the screen used in the primary screening operation is preferably 2-4 mm, more preferably 3 mm. This invention controls the aperture of the screen used in the primary screening operation within the above range to screen out minerals of suitable particle size, while simultaneously screening out unsuitable particle sizes for further crushing, avoiding over-grinding and improving production efficiency.

[0041] After obtaining the oversize product I, the present invention returns the oversize product I to the crushing operation for recycling.

[0042] After obtaining the undersize product I, the present invention performs a two-stage sieving operation on the undersize product I to obtain the oversize product II and the undersize product II.

[0043] In this invention, the aperture of the screen used in the secondary screening operation is preferably 0.3–0.7 mm, more preferably 0.4–0.6 mm, and even more preferably 0.5 mm. This invention controls the aperture of the screen used in the secondary screening operation within the above range to obtain minerals of suitable particle size for beneficiation.

[0044] After obtaining the oversize product II, the present invention performs heavy medium separation on the oversize product II to obtain the overflow product and the underflow product.

[0045] In this invention, the equipment used for heavy medium separation is preferably a heavy medium cyclone separator; the pressure of the heavy medium cyclone separator is preferably 0.10–0.20 MPa, more preferably 0.13–0.17 MPa, and even more preferably 0.15 MPa. This invention controls the pressure of the heavy medium cyclone separator within the above range to improve separation accuracy, optimize separation efficiency, and suit various material characteristics.

[0046] In this invention, the heavy medium suspension used in the heavy medium separation operation is preferably prepared using ferrosilicon powder as the heavy medium; the density of the heavy medium suspension is preferably 1.90–2.30 g / cm³. 3 More preferably, it is 1.94–1.98 g / cm³. 3 This invention controls the density of the heavy medium suspension within the above-mentioned range to improve sorting accuracy, optimize sorting efficiency, and is suitable for various material characteristics.

[0047] In this invention, the density of the ferrosilicon powder is preferably 6.9 g / cm³. 3 The particle size of the ferrosilicon powder is preferably 0.065–0.08 mm, more preferably 0.070–0.078 mm, and even more preferably 0.074 mm. This invention controls the density and particle size of the ferrosilicon powder within the above ranges to reduce production costs, reduce heavy medium loss, improve the stability of heavy medium suspensions, and adapt to various mineral feed particle sizes.

[0048] The principle of heavy medium separation in this invention is to place ore crushed to a certain particle size into a fluid with a density greater than water (i.e., heavy medium). According to the principle of buoyancy, mineral particles with a density less than that of the heavy medium will float, while those with a density greater than that of the medium will sink. By separately collecting the two products, heavy medium separation is achieved. The working principle of the heavy medium hydrocyclone is as follows: the ore, along with the heavy medium suspension, is fed into the hydrocyclone under pressure. During the rotational motion, the mineral particles are distributed into the corresponding density layers of the suspension according to their different densities. The heavy mineral particles located in the outer rotating flow move downward and are discharged from the bottom outlet, becoming the heavy product; the light mineral particles located in the inner rotating flow move upward and are discharged from the overflow pipe, becoming the light product.

[0049] After obtaining undersize product II, the present invention performs spiral chute separation operation on undersize product II to obtain lead-zinc-silver rough concentrate II and tailings II.

[0050] In this invention, the feed concentration for the spiral chute separation operation is preferably 20% to 40%. This invention controls the feed concentration within this range to ensure optimal separation efficiency and effect, adapting to various mineral types. In this invention, the spiral chute is preferably a Φ1200 type spiral chute.

[0051] In this invention, the spiral chute separation process utilizes an inclined water flow method. The mineral particle mixture is fed into an inclined chute with a small angle (generally 3°–4°, not exceeding 6°). Under the combined action of the water flow's force, gravity, centrifugal force, and friction, the mineral particles are stratified according to density. Because the water flow velocity distribution in the chute is higher at the top and lower at the bottom, the denser mineral particles concentrate in the lower layer, experiencing less water flow force and greater friction at the chute bottom, moving slowly forward along the bottom. The less dense mineral particles concentrate in the upper layer, are carried by the water flow, and flow out of the chute at a faster speed. Then, by separating the layers, two products with different densities—a rough concentrate and tailings—are obtained.

[0052] After obtaining the overflow product, the present invention performs a demediuming operation on the overflow product to obtain lead-zinc-silver rough concentrate I and heavy medium.

[0053] After obtaining the underflow products, the present invention performs a demediuming operation on the underflow products to obtain tailings I and heavy media.

[0054] In this invention, both lead-zinc-silver rough concentrate II and lead-zinc-silver rough concentrate I are high-grade and high-quality lead-zinc-silver ores that can be directly fed into the next beneficiation process, which simplifies the beneficiation process and greatly reduces its beneficiation cost.

[0055] In this invention, the equipment used for the desliming operation is preferably a desliming screen and a strong magnetic permanent magnet drum separator.

[0056] After obtaining the heavy medium, the present invention recycles and reuses the heavy medium.

[0057] This invention reduces production costs by recycling and reusing heavy media.

[0058] In this invention, both tailings I and tailings II are gangue minerals. The two are combined into the final tailings, which do not contain any mineral processing reagents. They can be directly used as filling material to fill the mined-out areas of the mine or sold as sand and gravel. This can effectively reduce production costs or generate economic benefits, and is also green and environmentally friendly.

[0059] The method provided by this invention improves the grade of lead, zinc, and silver feed minerals while discarding some gangue minerals. It fully utilizes the significant difference in specific gravity between lead, zinc, and silver minerals and gangue minerals, and separates them using a heavy medium cyclone separator and a spiral sluice to discard some gangue minerals, thus pre-enriching lead, zinc, and silver. This helps simplify subsequent beneficiation processes, reduces beneficiation costs, and the pre-discarded gangue minerals do not contain any beneficiation reagents and can be directly used as filling material for mine goaf areas or sold as sand and gravel, which contributes to the construction of green mines.

[0060] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0061] Figure 1 The process flow diagram in Embodiment 1 of the present invention includes: crushing operation, primary screening operation, secondary screening operation, heavy medium separation operation, spiral chute separation operation, and desliming operation.

[0062] Example 1

[0063] A method for pre-enriching lead-zinc-silver in low-grade lead-zinc-silver ore, comprising the following steps:

[0064] S1. The low-grade lead-zinc-silver ore to be processed is a lead-zinc polymetallic ore (also known as raw ore) from a certain place in Yunnan Province, which contains 0.95% lead, 4.24% zinc and 97.89 g / t silver.

[0065] The low-grade lead-zinc-silver ore to be processed is crushed, and the crushed ore is screened using a 3mm mesh screen to obtain oversize product I and undersize product I.

[0066] The oversize product I is returned to the crushing operation for recycling.

[0067] S2. The undersize product I from step S1 is subjected to a secondary sieving operation using a sieve with a pore size of 0.5 mm to obtain the oversize product II with a particle size of 0.5-3 mm and the undersize product II with a particle size of ≤0.5 mm.

[0068] S3. The oversize product II obtained in step S2 is subjected to heavy medium separation using a heavy medium hydrocyclone, with a heavy medium suspension density of 1.95 g / cm³. 3 The pressure of the heavy medium hydrocyclone was 0.15 MPa. The overflow and underflow of the heavy medium hydrocyclone were separately collected to obtain the overflow product and the underflow product.

[0069] The heavy medium suspension is prepared using ferrosilicon powder with a particle size of 0.074 mm (-200 mesh) as the heavy medium, and the density of the ferrosilicon powder is 6.9 g / cm³. 3 ;

[0070] The undersize product II obtained in step S2 is separated by a spiral chute. The feed concentration for the spiral chute separation is 30.00%, resulting in tailings II and lead-zinc-silver rough concentrate II.

[0071] S4. The overflow product and underflow product obtained in step S3 are subjected to demediuming operations to obtain lead-zinc-silver rough concentrate I, tailings I and heavy medium, and the heavy medium (i.e. ferrosilicon powder) is recovered and returned to the heavy medium separation system for recycling.

[0072] Tailings I and tailings II are combined and treated separately as tailings.

[0073] The main technical parameters of each product obtained in Example 1 are shown in Table 1.

[0074] Example 2

[0075] A method for pre-enriching lead-zinc-silver in low-grade lead-zinc-silver ore, comprising the following steps:

[0076] S1. The low-grade lead-zinc-silver ore to be processed is a lead-zinc polymetallic ore (also known as raw ore) from a certain place in Yunnan Province, containing 2.01% lead, 5.59% zinc, and 22.86 g / t silver.

[0077] The low-grade lead-zinc-silver ore to be processed is crushed, and the crushed ore is screened using a 3mm mesh screen to obtain oversize product I and undersize product I.

[0078] The oversize product I is returned to the crushing operation for recycling.

[0079] S2. The undersize product I from step S1 is subjected to a secondary sieving operation using a sieve with a pore size of 0.5 mm to obtain the oversize product II with a particle size of 0.5-3 mm and the undersize product II with a particle size of ≤0.5 mm.

[0080] S3. The oversize product II obtained in step S2 is subjected to heavy medium separation using a heavy medium hydrocyclone, with a heavy medium suspension density of 2.05 g / cm³. 3 The pressure of the heavy medium hydrocyclone was 0.15 MPa. The overflow and underflow of the heavy medium hydrocyclone were separately collected to obtain the overflow product and the underflow product.

[0081] The heavy medium suspension is prepared using ferrosilicon powder with a particle size of 0.074 mm (-200 mesh) as the heavy medium, and the density of the ferrosilicon powder is 6.9 g / cm³. 3 ;

[0082] The undersize product II obtained in step S2 is separated by a spiral chute. The feed concentration for the spiral chute separation is 25.00%, resulting in tailings II and lead-zinc-silver rough concentrate II.

[0083] S4. The overflow product and underflow product obtained in step S3 are subjected to demediuming operations to obtain lead-zinc-silver rough concentrate I, tailings I and heavy medium, and the heavy medium (i.e. ferrosilicon powder) is recovered and returned to the heavy medium separation system for recycling.

[0084] Tailings I and tailings II are combined and treated separately as tailings.

[0085] The main technical parameters of each product obtained in Example 1 are shown in Table 1.

[0086] In Table 1, the yield = (product quality / feed quality) * 100%; the grade is obtained by spectral analysis and titration, and the recovery rate = (product yield * product grade) / feed grade.

[0087] Table 1. Test results of the products obtained in Examples 1 and 2

[0088]

[0089]

[0090] Note: *Unit is g / t

[0091] In summary, the method provided by this invention yielded high-quality, high-grade lead-zinc-silver ore in Examples 1 and 2, while effectively reducing the amount of reagents used in subsequent beneficiation processes, lowering production costs, and significantly improving production efficiency. The method provided by this invention first crushes the low-grade lead-zinc-silver ore to be processed, partially liberating the lead, zinc, and silver minerals. Then, it performs two screening operations on the crushed low-grade lead-zinc-silver ore using standard sieves of different apertures, obtaining two particle size fractions: oversize product II and undersize product II. This fully utilizes the significant difference in specific gravity between lead-zinc-silver minerals and gangue minerals. A spiral chute is used to separate undersize product II for pre-enrichment of lead, zinc, and silver, and a heavy media separator is used to separate oversize product II to remove gangue minerals, achieving pre-enrichment of lead, zinc, and silver in the low-grade lead-zinc-silver ore. Finally, three products are obtained: lead-zinc-silver rough concentrate I, lead-zinc-silver rough concentrate II, and tailings (including tailings I and tailings II). The method provided by this invention enables the pre-enrichment of lead, zinc, and silver in low-grade lead-zinc-silver ore. The resulting lead-zinc-silver rough concentrate I and II are high-grade lead-zinc-silver ore after enrichment and can proceed to the next beneficiation process, simplifying the beneficiation process and significantly reducing beneficiation costs. Heavy media are recovered and recycled, further reducing production costs. The resulting tailings consist entirely of gangue minerals, containing no beneficiation reagents, and can be directly used as backfill material to fill mine goaf areas or sold as sand and gravel, effectively reducing production costs and generating economic benefits, while also being environmentally friendly. The method provided by this invention is simple in process, easy to operate, suitable for large-scale industrial applications, and has significant economic benefits and environmental advantages.

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for pre-enriching lead-zinc-silver in low-grade lead-zinc-silver ore, characterized in that, Includes the following steps: S1. The low-grade lead-zinc-silver ore to be processed is subjected to crushing and primary screening operations in sequence to obtain oversize product I and undersize product I. The oversize product I is returned to the crushing operation for recycling. S2. Perform a secondary sieving operation on the undersize product I in step S1 to obtain the oversize product II and the undersize product II; S3. The oversize product II obtained in step S2 is subjected to heavy medium separation to obtain overflow product and underflow product; The equipment used for heavy medium separation in step S3 is a pressurized two-product heavy medium cyclone separator; the pressure of the pressurized two-product heavy medium cyclone separator is 0.10~0.20MPa; The undersize product II obtained in step S2 is subjected to spiral chute separation to obtain lead-zinc-silver rough concentrate II and tailings II. The slurry concentration in the spiral chute separation operation in step S3 is 20%~40%; the spiral chute is a Φ1200 type spiral chute. S4. Perform demediuming operations on the overflow product and underflow product obtained in step S3 to obtain lead-zinc-silver rough concentrate I, tailings I and heavy medium; The heavy medium is recycled and reused.

2. The method according to claim 1, characterized in that, The aperture of the screen used in the primary screening operation in step S1 is 2~4mm.

3. The method according to claim 1, characterized in that, The aperture of the screen used in the secondary screening operation in step S2 is 0.3~0.7mm.

4. The method according to claim 1 or 3, characterized in that, The aperture of the screen used in the secondary screening operation in step S2 is 0.4~0.6mm.

5. The method according to claim 1, characterized in that, In step S3, the heavy medium suspension used in the heavy medium separation operation is prepared using ferrosilicon powder as the heavy medium; the density of the heavy medium suspension is 1.90~2.30 g / cm³. 3 .

6. The method according to claim 5, characterized in that, The density of the ferrosilicon powder is 6.9 g / cm³. 3 The particle size of the ferrosilicon powder is 0.065~0.08mm.

7. The method according to claim 6, characterized in that, The particle size of the ferrosilicon powder is 0.070~0.078mm.

8. The method according to claim 1, characterized in that, The equipment used in step S4 for the desliming operation is a desliming screen and a strong magnetic permanent magnet drum separator.

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