Method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ore

Abstract

The invention provides a method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ore, and belongs to the technical field of ore dressing. The method comprises the steps that firstly, to-be-treated low-grade raw lead-zinc-silver ore is crushed, then standard sieves with different hole diameters are sequentially used for screening twice, an oversize product II and an undersize product II are obtained, the undersize product II is separated through a spiral chute, the oversize product II is separated through dense medium separation equipment, and the separated oversize product II is separated through the dense medium separation equipment, so that the low-grade raw lead-zinc-silver ore is obtained. And finally, lead-zinc-silver rough concentrate I, lead-zinc-silver rough concentrate II and tailings are obtained. According to the method, lead, zinc and silver in the low-grade lead-zinc-silver ore raw ore are pre-enriched, the high-grade lead-zinc-silver ore is obtained and enters the next ore dressing process, the ore dressing process can be simplified, and the ore dressing cost of the ore dressing process can be greatly reduced; heavy media are recycled, so that the production cost is reduced; the obtained tailings do not contain any beneficiation reagent, and can be directly used as a filling material to fill a mine goaf or sold as gravel, so that the production cost can be effectively reduced or economic benefits can be generated.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing, and in particular to a method for pre-enriching lead, zinc and silver from a low-grade lead-zinc-silver ore. Background Art

[0002] The difficulty, high cost and low efficiency of beneficiation of low-grade lead-zinc-silver ores have become urgent problems to be solved in the industry. Traditional beneficiation methods mainly rely on flotation and gravity separation, but the effect is not ideal in the treatment of low-grade ores. Although flotation can effectively separate minerals, it consumes a lot of reagents, causes serious environmental pollution and has high processing costs. Gravity separation, as an environmentally friendly physical beneficiation method, has the advantages of low cost and simple process, but its effect on low-grade ores is limited. On the whole, low-grade lead-zinc-silver ores urgently need efficient and environmentally friendly pre-enrichment technology to improve ore processing efficiency. Summary of the invention

[0003] The object of the present invention is to provide a method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ore. The method provided by the present invention realizes the efficient enrichment of lead, zinc and silver in low-grade lead-zinc-silver ore, reduces the content of associated gangue in the ore, provides high-quality selected ore for subsequent mineral processing, does not require the selection of surrounding rock and waste rock, reduces grinding and selection consumption, reduces costs, and is green and environmentally friendly.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for pre-enriching lead, zinc and silver from a 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 operation and primary screening operation in sequence to obtain oversize product I and undersize product I;

[0007] The above-screen product I is returned to the crushing operation for recycling treatment;

[0008] S2. Performing secondary screening on the undersize product I in step S1 to obtain an oversize product II and an undersize product II;

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

[0010] The undersize product II obtained in step S2 is subjected to a spiral chute sorting operation to obtain a lead-zinc-silver coarse concentrate II and tailings II;

[0011] S4. The overflow product and the underflow product obtained in step S3 are subjected to de-mediation operations respectively to obtain lead-zinc-silver coarse concentrate I, tailings I and heavy medium;

[0012] The heavy medium is recovered and recycled.

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

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

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

[0016] Preferably, the equipment used for the heavy medium separation operation in step S3 is a heavy medium cyclone; the pressure of the heavy medium cyclone is 0.10-0.20 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 / cm 3 .

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

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

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

[0021] Preferably, the pulp concentration of the spiral chute sorting operation in step S3 is 20% to 40%; and the spiral chute is a Φ1200 type spiral chute.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0023] 1. Improve the recovery rate: The present invention can significantly improve the grades of lead, zinc and silver through gravity pre-enrichment, thereby improving the metal recovery rate of low-grade ores and improving the economic benefits of mineral processing;

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

[0025] 3. Simplified process: The method provided by the present invention provides high-quality ore for the next mineral processing step, simplifies the subsequent mineral processing process and makes it easy to control, reducing the high requirements for subsequent process equipment;

[0026] 4. Environmentally friendly: The present invention uses gravity pre-enrichment without the use of chemical agents, and can reduce the amount of agents used in subsequent mineral processing processes, which is more in line with the requirements of modern green mine construction;

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

[0028] In summary, the method for pre-enriching lead, zinc and silver in low-grade lead-zinc-silver ore provided by the present invention has significant advantages in processing low-grade lead-zinc-silver ore, enables low-grade ore to be used economically and effectively, solves the problems of difficulty in selecting low-grade lead-zinc-silver ore, high ore dressing cost, and complex ore dressing process, and provides a new idea for the efficient development of mining resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a process flow chart of Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The present invention provides a method for pre-enriching lead, zinc and silver from a 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 operation and primary screening operation in sequence to obtain oversize product I and undersize product I;

[0032] The above-screen product I is returned to the crushing operation for recycling treatment;

[0033] S2. Performing secondary screening on the undersize product I in step S1 to obtain an oversize product II and an undersize product II;

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

[0035] The undersize product II obtained in step S2 is subjected to a spiral chute sorting operation to obtain a lead-zinc-silver coarse concentrate II and tailings II;

[0036] S4. The overflow product and the underflow product obtained in step S3 are subjected to de-mediation operations respectively to obtain lead-zinc-silver coarse concentrate I, tailings I and heavy medium;

[0037] The heavy medium is recovered and recycled.

[0038] In the present invention, unless otherwise specified, the raw materials used are conventional commercial products in the art.

[0039] The present invention sequentially performs crushing operation and primary screening operation on the low-grade lead-zinc-silver ore to be processed to obtain an oversize product I and an undersize product I.

[0040] In the present invention, the aperture of the screen used in the primary screening operation is preferably 2-4 mm, more preferably 3 mm. The present invention controls the aperture of the screen used in the primary screening operation within the above range to screen out minerals with particle sizes suitable for selection, and at the same time screen out products of particle sizes that are not suitable for selection, and re-crush them to avoid over-crushing and improve production efficiency.

[0041] After obtaining the oversize product I, the present invention returns the oversize product I to the crushing operation for circulation treatment;

[0042] After obtaining the undersize product I, the present invention performs a secondary screening operation on the undersize product I to obtain an oversize product II and an undersize product II.

[0043] In the present 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 further preferably 0.5 mm. The present invention controls the aperture of the screen used in the secondary screening operation within the above range to obtain minerals with suitable particle sizes.

[0044] The oversize product II is obtained. In the present invention, the oversize product II is subjected to heavy medium separation operation to obtain overflow product and underflow product.

[0045] In the present invention, the equipment used for the heavy medium separation operation is preferably a heavy medium cyclone; the pressure of the heavy medium cyclone is preferably 0.10-0.20 MPa, more preferably 0.13-0.17 MPa, and further preferably 0.15 MPa. The present invention controls the pressure of the heavy medium cyclone within the above range to (improve the separation accuracy, optimize the separation efficiency, and be suitable for various material characteristics.

[0046] In the present 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 / cm 3 , more preferably 1.94 to 1.98 g / cm 3 The present invention controls the density of the heavy medium suspension within the above range to improve the sorting accuracy, optimize the sorting efficiency, and be suitable for various material properties.

[0047] In the present invention, the density of the ferrosilicon powder is preferably 6.9 g / cm 3 The particle size of the ferrosilicon powder is preferably 0.065-0.08 mm, more preferably 0.070-0.078 mm, and further preferably 0.074 mm. The density and particle size of the ferrosilicon powder are controlled within the above ranges to reduce production costs, reduce heavy medium loss, improve the stability of heavy medium suspension, and adapt to the particle size of various minerals.

[0048] The principle of heavy medium separation in the present invention is to put the ore crushed to a certain particle size into a fluid with a density greater than water (i.e., heavy medium). According to the buoyancy principle, the mineral particles with a density less than that of the heavy medium will float, while the mineral particles with a density greater than that of the medium will sink. The two products are intercepted separately, thus achieving heavy medium separation. The working principle of the heavy medium cyclone is as follows: the ore and the heavy medium suspension are fed into the cyclone under pressure. During the rotational motion, the mineral particles are distributed to the corresponding density layer of the suspension according to their own density; the heavy mineral particles in the outer layer of the rotating flow move downward and are discharged from the bottom flow port to become heavy products; the light mineral particles in the inner layer of the rotating flow move upward and are discharged from the overflow pipe to become light products.

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

[0050] In the present invention, the feed concentration of the spiral chute sorting operation is preferably 20% to 40%. The present invention controls the feed concentration of the spiral chute sorting operation within the above range to ensure the optimization of sorting efficiency and sorting effect, and adapt to various mineral types. In the present invention, the spiral chute is preferably a Φ1200 spiral chute.

[0051] The spiral chute sorting operation in the present invention is a sorting process using the inclined water flow method. The ore particle mixture is fed into an inclined chute with a small inclination angle (generally 3° to 4°, not more than 6°). The ore particles are layered according to density under the combined effects of the water flow force, gravity, centrifugal force, and friction. Since the velocity distribution of the water flow in the chute is large in the upper layer and small in the lower layer, the ore particles with higher density are concentrated in the lower layer, and are subjected to smaller water flow force and larger friction force at the bottom of the chute, and move forward slowly along the bottom of the chute. The ore particles with lower density are concentrated in the upper layer, carried by the water flow, and flow out of the chute at a faster speed. Then, the two products of coarse concentrate and tailings with different densities can be obtained by intercepting the flow according to the layers.

[0052] After the overflow product is obtained, the present invention performs a de-mediuming operation on the overflow product to obtain lead-zinc-silver coarse concentrate I and heavy medium.

[0053] After obtaining the underflow product, the present invention performs a de-mediuming operation on the underflow product to obtain tailings I and heavy medium.

[0054] The lead-zinc-silver rough concentrate II and the lead-zinc-silver rough concentrate I in the present invention are both high-grade, high-quality lead-zinc-silver ores, which directly enter the next mineral processing step, can simplify the mineral processing technology and greatly reduce its mineral processing cost.

[0055] In the present invention, the equipment used for the de-mediation operation is preferably a de-mediation screen and a strong magnetic permanent magnetic drum magnetic separator.

[0056] After obtaining the heavy medium, the present invention recycles the heavy medium for reuse.

[0057] The invention reduces production cost by recycling the heavy medium.

[0058] In the present invention, both tailings I and tailings II are gangue minerals. The final tailings combined by the two do not contain any mineral processing agents and can be directly used as filling materials to fill mine goafs or sold as sand and gravel, which can effectively reduce production costs or generate economic benefits and is green and environmentally friendly.

[0059] The method provided by the present invention improves the selected grade of lead, zinc and silver, and at the same time discards part of the gangue minerals, making full use of the characteristic that there is a large difference in the specific gravity of lead, zinc and silver minerals and gangue minerals, sorting them through a heavy medium cyclone and a spiral chute, discarding part of the gangue minerals, and pre-enriching the lead, zinc and silver, which is helpful to simplify the subsequent mineral processing process and reduce the mineral processing cost; the gangue minerals discarded in advance do not contain any mineral processing reagents and can be directly used as filling materials to fill the mine goaf or sold as sand and gravel, which is helpful to build a green mine.

[0060] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Figure 1 This is a process flow chart of Example 1 of the present invention, including: crushing operation, primary screening operation, secondary screening operation, heavy medium separation operation, spiral chute separation operation, and medium removal operation.

[0062] Example 1

[0063] A method for pre-enriching lead, zinc and silver from a 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) in a certain place in Yunnan, which contains 0.95% lead, 4.24% zinc and 97.89g / t silver;

[0065] The low-grade lead-zinc-silver ore to be processed is crushed, and the crushed ore is screened using a sieve with an aperture of 3 mm to obtain an oversize product I and an undersize product I;

[0066] The above-screen product I is returned to the crushing operation for recycling treatment;

[0067] S2. The undersize product I in step S1 is subjected to secondary screening using a sieve with a pore size of 0.5 mm to obtain an oversize product II with a particle size of 0.5 to 3 mm and an undersize product II with a particle size of ≤0.5 mm;

[0068] S3. The above-sieve product II obtained in step S2 is subjected to heavy medium separation using a heavy medium cyclone, and the density of the heavy medium suspending agent is 1.95 g / cm 3 The pressure of the heavy medium cyclone is 0.15Mpa. The overflow and underflow of the heavy medium cyclone are intercepted respectively to obtain overflow products and underflow products.

[0069] The heavy medium suspension is prepared by 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 / cm 3 ;

[0070] The undersize product II obtained in step S2 is subjected to spiral chute sorting operation using a spiral chute, wherein the feed concentration of the spiral chute sorting operation is 30.00%, to obtain tailings II and lead-zinc-silver coarse concentrate II;

[0071] S4. The overflow product and the underflow product obtained in step S3 are subjected to de-mediuming operations respectively to obtain lead-zinc-silver coarse 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] The tailings I and II are combined into tailings and processed separately.

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

[0074] Example 2

[0075] A method for pre-enriching lead, zinc and silver from a 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) in a certain place in Yunnan, which contains 2.01% lead, 5.59% zinc and 22.86g / t silver;

[0077] The low-grade lead-zinc-silver ore to be processed is crushed, and the crushed ore is screened using a sieve with an aperture of 3 mm to obtain an oversize product I and an undersize product I;

[0078] The above-screen product I is returned to the crushing operation for recycling treatment;

[0079] S2. The undersize product I in step S1 is subjected to secondary screening using a sieve with a pore size of 0.5 mm to obtain an oversize product II with a particle size of 0.5 to 3 mm and an undersize product II with a particle size of ≤0.5 mm;

[0080] S3. The above-sieve product II obtained in step S2 is subjected to heavy medium separation using a heavy medium cyclone, and the density of the heavy medium suspending agent is 2.05 g / cm 3 The pressure of the heavy medium cyclone is 0.15Mpa. The overflow and underflow of the heavy medium cyclone are intercepted respectively to obtain overflow products and underflow products.

[0081] The heavy medium suspension is prepared by 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 / cm 3 ;

[0082] The undersize product II obtained in step S2 is subjected to spiral chute sorting operation using a spiral chute, wherein the feed concentration of the spiral chute sorting operation is 25.00%, to obtain tailings II and lead-zinc-silver coarse concentrate II;

[0083] S4. The overflow product and the underflow product obtained in step S3 are subjected to de-mediuming operations respectively to obtain lead-zinc-silver coarse 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] The tailings I and II are combined into tailings and processed separately.

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

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

[0087] Table 1 Test results of products obtained in Example 1 and Example 2

[0088]

[0089]

[0090] Note: *Unit is g / t

[0091] It can be seen from the summary that, by adopting the method provided by the present invention, Examples 1 and 2 obtain high-quality high-grade lead-zinc-silver ore, and at the same time effectively reduce the dosage of reagents in the subsequent beneficiation process, reduce production costs, and significantly improve production efficiency. The method provided by the present invention first crushes the low-grade lead-zinc-silver ore to be processed to partially dissociate its lead-zinc-silver minerals, and then uses standard sieves with different apertures to perform two screening operations on the crushed low-grade lead-zinc-silver ore to obtain two particle size screening products, namely, the screen product II and the screen product II, which fully utilizes the characteristics that there is a large difference in the specific gravity of lead-zinc-silver minerals and gangue minerals, and uses a spiral chute to sort the screen product II to pre-enrich lead, zinc and silver, and uses a heavy medium sorting device to sort the screen product II to remove gangue minerals, so as to achieve pre-enrichment of lead, zinc and silver in low-grade lead-zinc-silver ore, and finally obtains three products of lead-zinc-silver rough concentrate I, lead-zinc-silver rough concentrate II, and tailings (including tailings I and tailings II). The method provided by the present invention can realize the pre-enrichment of lead, zinc and silver in low-grade lead-zinc-silver ore, and the obtained lead-zinc-silver rough concentrate I and lead-zinc-silver rough concentrate II belong to the enriched lead-zinc-silver ore with higher grade, which enters the next beneficiation process, can simplify the beneficiation process and greatly reduce its beneficiation cost; the heavy medium is recovered and recycled to reduce production costs; the obtained tailings are all gangue minerals, do not contain any beneficiation reagents, can be directly used as filling materials to fill the mine goaf or sold as sand and gravel, can effectively reduce production costs or generate economic benefits, and are green and environmentally friendly. The method provided by the present invention has simple process, convenient operation, is suitable for large-scale industrial application, and has significant economic benefits and environmental advantages.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for pre-enriching lead, zinc and silver from low-grade lead, zinc and silver ore, characterized in that: The following steps are involved: S1. The low-grade lead-zinc-silver ore to be processed is subjected to crushing operation and primary screening operation in sequence to obtain oversize product I and undersize product I; The above-screen product I is returned to the crushing operation for recycling treatment; S2. Performing secondary screening on the undersize product I in step S1 to obtain an oversize product II and an undersize product II; S3. The oversize product II obtained in step S2 is subjected to heavy medium separation to obtain an overflow product and an underflow product; The undersize product II obtained in step S2 is subjected to a spiral chute sorting operation to obtain a lead-zinc-silver coarse concentrate II and tailings II; S4. The overflow product and the underflow product obtained in step S3 are subjected to de-mediation operations respectively to obtain lead-zinc-silver coarse concentrate I, tailings I and heavy medium; The heavy medium is recovered and recycled.

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

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

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

5. The method according to claim 1, characterized in that The equipment used for the heavy medium separation operation in step S3 is a pressurized two-product heavy medium cyclone; the pressure of the pressurized two-product heavy medium cyclone is 0.10-0.20 MPa.

6. The method according to claim 1 or 5, characterized in that: 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 / cm 3 .

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

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

9. The method according to claim 1, characterized in that: The equipment used for the medium removal operation in step S4 is a medium removal screen and a strong magnetic permanent magnetic drum magnetic separator.

10. The method according to claim 1, characterized in that The slurry concentration of the spiral chute sorting operation in step S3 is 20% to 40%; the spiral chute is a Φ1200 type spiral chute.

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