Method for separating lead-zinc sulfide ore through cooperation of magnetic separation and flotation

Abstract

The invention discloses a method for separating lead-zinc sulfide ore through cooperation of magnetic separation and flotation, and relates to the technical field of mineral processing engineering. The separation method of the lead-zinc sulfide ore comprises the following processes of gradient magnetic separation pre-enrichment, grading treatment, selective regrinding, lead flotation and zinc flotation. Gradient magnetic separation is combined with a novel efficient flotation reagent system, and efficient separation of lead-zinc sulfide ore is achieved. Compared with a traditional process, the method has the advantages that the grade of the lead-zinc concentrate is improved, the recovery rate is also improved, meanwhile, agent consumption is remarkably reduced, and the method has the advantages of being simple in technological process, high in adaptability, environmentally friendly and the like and is particularly suitable for industrial separation of high-sulfur complex lead-zinc ore.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral processing engineering, and more particularly, to a method for synergistic separation of lead-zinc sulfide ores by magnetic separation and flotation. Background Art

[0002] The symbiotic relationship between pyrrhotite and lead-zinc sulfide ores is relatively common in nature, especially in polymetallic ore deposits. As a strongly magnetic mineral, pyrrhotite has significant differences in physical properties from lead-zinc minerals. For example, pyrrhotite has a greater hardness and is magnetic, while lead-zinc minerals are brittle and unevenly disseminated in particle size. Such mineralogical characteristics cause the presence of pyrrhotite to significantly interfere with the flotation separation of lead-zinc minerals during the ore dressing process.

[0003] Currently, when ore dressing plants process lead-zinc sulfide ores containing pyrrhotite, they usually adopt a single grinding operation followed by flotation separation. The flotation process mainly includes suppressing pyrrhotite, preferentially floating lead-zinc minerals, and finally separating lead and zinc. However, due to the strong magnetic and hard characteristics of pyrrhotite, it is prone to mechanical entrapment with lead-zinc minerals during the flotation process, resulting in the deterioration of the lead-zinc flotation separation effect.

[0004] To alleviate this problem, some ore dressing plants attempt to pre-remove pyrrhotite by magnetic separation after grinding, and then perform lead-zinc separation on the magnetic separation tailings, or directly perform lead-zinc separation after grinding. Nevertheless, the existing technologies still face many challenges in processing lead-zinc sulfide ores containing pyrrhotite, including interference of pyrrhotite with flotation, insufficient selectivity of reagents, imperfect treatment of middlings, and poor environmental performance. These technical bottlenecks limit the further improvement of the separation efficiency and metal recovery rate of lead-zinc sulfide ores.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for synergistic separation of lead-zinc sulfide ores by magnetic separation and flotation to solve the above technical problems.

[0007] The present invention is implemented as follows:

[0008] In a first aspect, an embodiment of the present invention provides a method for synergistic separation of lead-zinc sulfide ores by magnetic separation and flotation, and the method includes the following process:

[0009] After grinding the raw ore, perform gradient magnetic separation pre-concentration to obtain magnetic separation concentrate and magnetic separation tailings, wherein the magnetic field intensity of the gradient magnetic separation is 800 Gs - 1500 Gs;

[0010] Perform classification on the magnetic separation concentrate to obtain coarse-grained products and fine-grained products;

[0011] Combine the coarse-grained products with the magnetic separation tailings for selective regrinding;

[0012] After subjecting the minerals after selective regrinding to lead flotation and zinc flotation in sequence, the separation of lead-zinc sulfide ores is achieved;

[0013] Among them, a sphalerite depressant and a galena collector are added for lead flotation; a sphalerite activator and a zinc mineral collector are added for zinc flotation.

[0014] The present invention has the following beneficial effects:

[0015] In the embodiment of the present invention, through gradient magnetic separation combined with a new type of high-efficiency flotation reagent system, the efficient separation of lead-zinc sulfide ores is achieved. Compared with the traditional process, the grade of lead-zinc concentrate is improved and the recovery rate is also increased. At the same time, the reagent consumption is significantly reduced. It has the advantages of simple process flow, strong adaptability, environmental friendliness, etc., and is particularly suitable for the industrial separation of high-sulfur complex lead-zinc ores. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a process flow schematic diagram of magnetic separation-flotation collaborative separation of lead-zinc sulfide ores in Embodiment 1;

[0018] Figure 2 It is a process flow schematic diagram of traditional separation of lead-zinc sulfide ores in Comparative Example 2. Detailed Embodiments

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0020] To further improve the following problems faced when processing lead-zinc sulfide ores containing pyrrhotite, such as the interference of pyrrhotite on flotation, insufficient reagent selectivity, imperfect middling treatment, or poor environmental performance, at least one of them, the present invention proposes an improvement scheme, which is specifically as follows:

[0021] In a first aspect, an embodiment of the present invention provides a method for magnetic separation-flotation collaborative separation of lead-zinc sulfide ores, and the method includes the following process:

[0022] After grinding the raw ore, it is subjected to gradient magnetic separation for pre-concentration to obtain magnetic separation concentrate and magnetic separation tailings. Among them, the magnetic field intensity of the gradient magnetic separation is 800 Gs - 1500 Gs;

[0023] The magnetic separation concentrate is classified to obtain coarse-grained products and fine-grained products;

[0024] The coarse-grained products are combined with the magnetic separation tailings for selective regrinding;

[0025] After the selectively reground minerals are subjected to lead flotation and zinc flotation in sequence, the separation of lead-zinc sulfide ores is achieved;

[0026] Among them, a sphalerite inhibitor and a galena collector are added for lead flotation; a sphalerite activator and a zinc mineral collector are added for zinc flotation.

[0027] It should be noted that the embodiment of the present invention realizes the efficient separation of lead-zinc sulfide ores through gradient magnetic separation combined with a new type of high-efficiency flotation reagent system. Compared with the traditional process, the grade of lead-zinc concentrates is increased by 2% - 4%, the recovery rate is increased by 4% - 6%, and at the same time, the reagent consumption is significantly reduced. It has the advantages of simple process flow, strong adaptability, environmental friendliness, etc., and is especially suitable for the industrial separation of high-sulfur complex lead-zinc ores.

[0028] In an alternative embodiment, among the magnetic field intensities of the gradient magnetic separation, the first-stage magnetic field intensity is 800 Gs - 1000 Gs, and the second-stage magnetic field intensity is 1200 Gs - 1500 Gs.

[0029] It should be noted that the instrument used in the gradient magnetic field magnetic separation process is not particularly limited in the present invention, and it is reasonably selected according to actual needs. Specifically, a permanent magnet drum magnetic separator is used in the embodiment of the present invention.

[0030] Before gradient magnetic separation, the raw ore is crushed and then ground, which is beneficial to improving the dissociation degree of minerals, optimizing the separation effect; making the particle size of minerals more uniform, avoiding the blockage of equipment by coarse particles, and at the same time enhancing the adsorption of reagents in the subsequent flotation process, accelerating the reaction rate, and improving the metal recovery rate. In addition, during the grinding process, it is also necessary to avoid excessive crushing of valuable minerals and reduce the metal recovery rate.

[0031] Gradient magnetic separation enhances the capture ability of weakly magnetic minerals, improves the separation efficiency of fine-grained minerals, realizes the selective separation of minerals, reduces energy consumption and improves the adaptability of equipment.

[0032] During the gradient magnetic separation process, for the setting of the magnetic field intensity, exemplary, the magnetic field intensity for the first separation can be selected from any one of 800 Gs, 850 Gs, 900 Gs, 950 Gs, and 1000 Gs, or other values within the range of 800 Gs - 1000 Gs; the magnetic field intensity for the second separation can be selected from any one of 1200 Gs, 1250 Gs, 1300 Gs, 1350 Gs, 1400 Gs, 1450 Gs, and 1500 Gs, or other values within the range of 1200 Gs - 1500 Gs.

[0033] In an alternative embodiment, the working pressure during the classification process is 0.12 MPa - 0.18 MPa, and the feed concentration is 25% - 35%; the particle size of the coarse-grained product is +0.074 mm, and the particle size of the fine-grained product is -0.074 mm; among them, the fine-grained product is high-sulfur iron concentrate.

[0034] It should be noted that the classification process is a key link for separating ore particles according to particle size, density, or settling velocity, and its core significance lies in optimizing the separation efficiency, controlling the product quality, and reducing energy consumption.

[0035] Applying pressure during the classification process has the following meanings: it can accelerate the separation of solids from liquids and materials with different densities or particle sizes; by adjusting the pressure magnitude, the critical point of separation can be precisely controlled to ensure that materials of different levels (such as particle size and density differences) are accurately divided; it can inhibit the flying or diffusion of light or fine particles, avoid cross-contamination, and improve the classification purity; applying pressure reasonably can shorten the processing time and reduce the energy consumption of subsequent processes.

[0036] In an alternative embodiment of the present invention, the specific value of the working pressure can be selected from any one of 0.12 MPa, 0.13 MPa, 0.15 MPa, 0.17 MPa, and 0.18 MPa, or other values within the range of 0.12 MPa - 0.18 MPa.

[0037] The setting of the feed concentration during the classification process directly affects the separation efficiency, energy consumption, product quality, and equipment operation stability. If the concentration is too high, it may lead to poor fluidity of the material, block the equipment (such as sieve meshes and centrifuge channels), and reduce the classification accuracy; the interaction force between particles (such as adhesion and agglomeration) increases, affecting the effective separation according to particle size or density. If the concentration is too low, the proportion of the medium (such as water or air) is too high, and the dilution effect will reduce the collision or sedimentation opportunities between particles, reducing the separation efficiency; in gravity or centrifugal classification, the thin slurry may cause fine particles to fail to sediment effectively, resulting in the loss of target components.

[0038] After comprehensively considering the separation objectives, material characteristics, equipment limitations, and economy, in the optional embodiments of the present invention, the feed concentration is reasonably adjusted according to the actual situation, and it can be selected from any one of 25%, 28%, 30%, 32%, and 35%, or other values within the range of 25% - 35%.

[0039] In the embodiments of the present invention, sorting is carried out according to particle size. The significance of particle size classification is that it can ensure that the ore particles reach the target dissociation degree, avoiding the influence of un-dissociated or over-crushed coarse particles on sorting; in addition, the classification process can reduce the equipment load and processing cost. In the embodiments of the present invention, the selected particle size is based on 0.074 mm. In other embodiments of the present invention, other particle sizes can be set according to actual needs for classification.

[0040] The present invention does not make special limitations on the instruments used in the classification process, and they are reasonably selected according to actual needs. Specifically, in the embodiments of the present invention, a supporting hydrocyclone is used, which has the characteristics of large processing capacity and small floor area.

[0041] In the optional embodiments, during the selective regrinding process, the mineral concentration is 50% - 65%, and the diameter Φ of the grinding medium is 10 mm - 15 mm; among the minerals after selective regrinding, the proportion of minerals with a particle size of -0.074 mm is 75% - 85%.

[0042] The significance of selective regrinding is to accurately improve the dissociation degree of the target mineral while avoiding over-grinding and energy consumption waste. In the embodiments of the present invention, the regrinding equipment used is a tower mill, which has significant advantages in energy conservation and consumption reduction, ultra-fine grinding, and improving the beneficiation recovery rate, etc. It is especially suitable for the deep dissociation of fine-grained disseminated ores and the ultra-fine processing of high-value minerals. In other embodiments of the present invention, other equipment can be selected according to actual needs for regrinding. The product after selective regrinding is classified by a high-frequency vibrating screen, and the oversize product is returned to the gradient magnetic separation for further operation.

[0043] The grinding medium is a carrier used to impact and grind the ore during the grinding process, and its material, shape, and size directly affect the grinding efficiency and product particle size. The material can be selected as steel balls, cast iron balls, ceramic balls, or grindstones according to actual needs. In the embodiments of the present invention, steel balls are used, which have the characteristics of high hardness, wear resistance, strong impact force, and small grinding area. The diameter of the grinding medium is reasonably adjusted according to the actual amount of material to be processed and the particle size situation, and it can be selected from any one of 10 mm, 11 mm, 12 mm, 14 mm, and 15 mm, or other values within the range of 10 mm - 15 mm.

[0044] During regrinding, the setting of the mineral concentration directly affects the grinding efficiency, energy consumption, equipment wear, and subsequent separation effect. If the mineral concentration is too high, the pulp is viscous, the movement of the medium is blocked, the grinding effect is weakened, which may lead to "overloading" (mill overload), an increase in the motor load, and the grinding effect may not necessarily be improved. If the mineral concentration is too low, the pulp is too dilute, the direct impact between the media increases, the wear is aggravated, the ore crushing efficiency is reduced, and energy consumption is wasted. The mineral concentration selected in the embodiment of the present invention is set after balancing the impact and grinding effects, which is conducive to maximizing the utilization of energy.

[0045] After regrinding, the setting of the proportion of mineral particle sizes directly affects the separation efficiency, energy consumption, and final concentrate grade. If the amount of regrinding ore is insufficient, the associated minerals cannot be fully dissociated, resulting in the loss of valuable minerals in the tailings and reducing the recovery rate. When the amount of regrinding ore is too large, it may cause over-grinding, increase the risk of slime formation, and instead reduce the flotation or leaching efficiency. From the perspective of balancing energy consumption and economic benefits, in the present invention, the proportion of minerals with a particle size of -0.074 mm in the selectively regrinded minerals is set to 75%-85% according to needs.

[0046] In an alternative embodiment, the lead flotation is carried out under the condition that the pH is 8.5-10.0; and / or, the lead flotation includes the following processes: one roughing, two scavengings, and two cleanings.

[0047] It should be noted that the pH of the lead flotation in the embodiment of the present invention is set to weakly alkaline. In this environment, the collector has a stronger adsorption ability for galena and a weaker adsorption for other sulfides, which is conducive to improving the separation efficiency of lead and zinc. In addition, the setting of the weakly alkaline environment is also conducive to inhibiting pyrite and the activation of zinc, reducing the mixing of zinc in the lead concentrate, increasing the selectivity of the galena collector, and thus improving the recovery rate of galena.

[0048] Among them, roughing is used for the preliminary separation of the raw ore, quickly separating out most of the valuable minerals to obtain rough concentrate; it has the characteristics of a large processing capacity, but a lower concentrate grade and may contain more impurities.

[0049] Scavenging is used for the reprocessing of the tailings after roughing or scavenging to recover the remaining valuable minerals in them and reduce metal loss. It focuses on improving the recovery rate. The tailings after scavenging are usually returned to roughing or treated separately; scavenging can be carried out cyclically in the flotation process.

[0050] Cleaning is used for the further purification of the tailings after scavenging or cleaning. By multiple flotation operations, the entrained gangue is removed to improve the final concentrate grade. Cleaning can be carried out cyclically in the flotation process. The implementation of multi-stage cleaning ensures that the concentrate meets the smelting or sales standards.

[0051] The specific process settings of lead flotation can be reasonably adjusted according to actual needs. In the embodiment of the present invention, one rough selection, two scavenging selections, and two cleaning selections are used.

[0052] In an alternative embodiment, based on the pulp quality, during the lead flotation process, the dosage of the sphalerite inhibitor is 80 g / t - 200 g / t; the sphalerite inhibitor is an L-cysteine derivative (LCYD), and its structural general formula is HS-CH2-CH(NH2)-CO-X, where X is selected from a carboxyl group, an ester group, or an amide group.

[0053] It should be noted that the use of L-cysteine derivative (LCYD) as the sphalerite inhibitor has the following significance: The sulfhydryl group (-SH) and carboxyl group (-COOH) of the L-cysteine derivative can form a stable chelate with Zn on the surface of sphalerite 2+ and selectively adsorb on the surface of sphalerite, with less influence on minerals such as galena (PbS) and pyrite (FeS2); in the flotation of lead-zinc-sulfur mixed ores, it can effectively inhibit sphalerite and achieve efficient separation of lead and zinc. In addition, this substance is biodegradable, meets the requirements of green ore dressing, does not contain harmful components such as chromium and cyanide, and reduces the environmental risk of tailings.

[0054] The dosage of the sphalerite inhibitor can be reasonably selected according to actual needs. Exemplarily, any one of 80 g / t, 100 g / t, 120 g / t, 150 g / t, 180 g / t, and 200 g / t can be selected, or other values within the range of 80 g / t - 200 g / t.

[0055] In an alternative embodiment, based on the pulp quality, during the lead flotation process, the dosage of the galena collector is 25 g / t - 60 g / t; the galena collector is a benzothiazole mercaptan collector, and its structural general formula is C7H4NS2-R, where R is selected from C1-C4 alkyl groups.

[0056] It should be noted that the use of benzothiazole mercaptan (BTT) as the galena collector has the following significance: The sulfur atom on the benzothiazole ring forms a stable four-membered ring chelate with Pb on the surface of galena 2+ and the adsorption strength is significantly higher than that of traditional xanthate collectors; in lead-zinc-sulfur mixed ores, its collecting effect on sphalerite (ZnS) and pyrite (FeS2) is weak, and the lead-zinc separation effect is significantly improved.

[0057] The dosage of the galena collector can be reasonably selected according to actual needs. Exemplarily, any one of 25 g / t, 30 g / t, 35 g / t, 40 g / t, 50 g / t, and 60 g / t can be selected, or other values within the range of 25 g / t - 60 g / t.

[0058] In an alternative embodiment, zinc flotation is carried out using the tailings of lead flotation, and the zinc flotation is carried out under the condition that the pH is 5.0 - 6.5; and / or, the zinc flotation includes the following process: one rough selection, two scavenging selections and three cleaning selections.

[0059] It should be noted that the pH of the zinc flotation is set to be weakly acidic, which is easy to promote the hydrolysis precipitation of Cu 2+ and improve the activation effect of sphalerite; in addition, it is also beneficial to inhibit the residual pyrite.

[0060] The specific process setting of the zinc flotation can be reasonably adjusted according to actual needs. In the embodiment of the present invention, one rough selection, two scavenging selections and three cleaning selections are used.

[0061] In an alternative embodiment, the sphalerite activator is selected from at least one of copper sulfate, copper chloride, sodium sulfide, lead nitrate, lead acetate and copper complex modified by graphene quantum dots (GQD-Cu); the copper complex is preferably copper-ethylenediaminetetraacetic acid complex; based on the mass of the pulp, during the zinc flotation process, the dosage of the sphalerite activator is 10 g / t - 30 g / t.

[0062] It should be noted that sphalerite has poor natural hydrophobicity. Usually, a salt containing Cu 2+ is added as the sphalerite activator, and its mechanism is to form a surface copper sulfide layer by replacing Zn 2+ with Cu 2+ . The pH of this process is set to be weakly acidic, which is easy to promote the hydrolysis precipitation of Cu 2+ and improve the activation effect of sphalerite.

[0063] The dosage of the sphalerite activator can be reasonably selected according to actual needs. Exemplarily, any one of 10 g / t, 15 g / t, 18 g / t, 20 g / t, 25 g / t and 30 g / t can be selected, or other values within the range of 10 g / t - 30 g / t.

[0064] In the optimal embodiment, the sphalerite activator used is copper complex modified by graphene quantum dots (GQD-Cu). Selecting this substance has the following significance: Through the quantum confinement effect, GQD-Cu makes the copper active sites distributed in the form of single atoms, and the replacement reaction rate with Zn 2+ on the sphalerite surface is higher than that of traditional CuSO4; the carboxyl group (-COOH) of GQDs forms a coordination bond with copper ions, and at the same time, the epoxy group (C-O-C) at the edge of the quantum dots can be adsorbed on the surface defect sites of ZnS, realizing the dual functions of "copper ion transportation + surface anchoring". In addition, the sp 2 hybrid carbon network of graphene quantum dots promotes the valence state conversion of Cu 2+ →Cu + and accelerates Zn on the ZnS surface2+ Dissolution.

[0065] In an optional embodiment, during the zinc flotation process, based on the mass of the pulp, the dosage of the zinc mineral collector is 30 g / t - 80 g / t; the zinc mineral collector is N,N-dimethyl-3-mercaptopropionamide (DMMPA).

[0066] It should be noted that the selection of N,N-dimethyl-3-mercaptopropionamide (DMMPA) as the zinc mineral collector has the following significance: The -SH (mercapto group) in the DMMPA molecule forms a strong covalent bond with Zn on the surface of sphalerite, while the adsorption ability for galena (PbS) and pyrite (FeS2) is weak, and the lead-zinc separation coefficient is significantly improved; the three-dimensional structure of N,N-dimethyl can hinder the non-selective adsorption of the collector on non-target minerals (such as silicate gangue), effectively improving the zinc grade of the concentrate. In addition, the DMMPA molecule has the characteristics of low toxicity and biodegradability, which is conducive to realizing green mineral processing. 2+ A strong covalent bond is formed, while the adsorption ability for galena (PbS) and pyrite (FeS2) is weak, and the lead-zinc separation coefficient is significantly improved; the three-dimensional structure of N,N-dimethyl can hinder the non-selective adsorption of the collector on non-target minerals (such as silicate gangue), effectively improving the zinc grade of the concentrate. In addition, the DMMPA molecule has the characteristics of low toxicity and biodegradability, which is conducive to realizing green mineral processing.

[0067] The dosage of the zinc mineral collector can be reasonably selected according to actual needs. Exemplarily, any one of 30 g / t, 35 g / t, 40 g / t, 50 g / t, 60 g / t, and 80 g / t can be selected, or other values within the range of 30 g / t - 80 g / t.

[0068] In summary, the method for synergistic separation of lead-zinc sulfide ore by magnetic separation - flotation provided by the present invention specifically includes the following process:

[0069] (1) Gradient magnetic separation pre-concentration: After the raw ore is crushed and ground, a permanent magnetic drum separator is used for gradient magnetic separation pre-concentration to obtain magnetic separation rough concentrate and tailings;

[0070] Among the magnetic field intensities of the gradient magnetic separation, the magnetic field intensity of the first separation is 800 Gs - 1000 Gs, and the magnetic field intensity of the second separation is 1200 Gs - 1500 Gs.

[0071] (2) Classification separation: The magnetic separation rough concentrate is subjected to classification treatment by a hydrocyclone to separate the fine-grained high-sulfur iron concentrate of -0.074 mm;

[0072] The working pressure during the classification treatment is 0.12 MPa - 0.18 MPa, and the feed concentration is 25% - 35%.

[0073] (3) Selective regrinding: The +0.074 mm coarse-grained product is combined with the magnetic separation tailings and re-ground to -0.074 mm accounting for 75% - 85% under the condition of a grinding concentration of 50% - 65%;

[0074] During the selective regrinding process, the mineral concentration is 50% - 65%, and the diameter Φ of the grinding medium is 10 mm - 15 mm.

[0075] (4) Lead preferential flotation: Using L-cysteine derivative (LCYD) as the depressant for sphalerite and benzothiazole mercaptan collector (BTT) as the collector for galena, lead flotation is carried out under the condition of pH 8.5 - 10.0 to obtain lead concentrate;

[0076] Based on the pulp mass, during the lead flotation process, the dosage of the sphalerite depressant is 80 g / t - 200 g / t; the dosage of the galena collector is 25 g / t - 60 g / t.

[0077] (5) Zinc flotation: Using graphene quantum dot-modified copper complex (GQD-Cu) as the activator for sphalerite and N,N-dimethyl-3-mercaptopropionamide (DMMPA) as the collector for zinc minerals, zinc flotation is carried out under the condition of pH 5.0 - 6.5 to obtain zinc concentrate.

[0078] Based on the pulp mass, during the zinc flotation process, the dosage of the sphalerite activator is 10 g / t - 30 g / t, and the dosage of the zinc mineral collector is 30 g / t - 80 g / t.

[0079] In an alternative embodiment,

[0080] The grade of the lead concentrate obtained after the separation of lead-zinc sulfide ore is ≥21%, and the grade of the zinc concentrate is ≥44%; the lead recovery rate is ≥65.29%, and the zinc recovery rate is ≥85.61%.

[0081] The characteristics and properties of the present invention are further described in detail below in conjunction with the embodiments.

[0082] Example 1

[0083] This example provides a method for the synergistic separation of lead-zinc sulfide ore by magnetic separation - flotation, which includes the following process:

[0084] (1) Gradient magnetic separation pre-concentration: After the raw ore is crushed and ground, gradient magnetic separation pre-concentration is carried out using a permanent magnetic drum separator to obtain magnetic separation rough concentrate and tailings;

[0085] Among them, the raw ore is a certain lead-zinc ore in Guangxi (Pb 2.36%, Zn 3.42%), and the raw ore is crushed to -2 mm and then ball milled to -0.074 mm accounting for 65%;

[0086] In the magnetic field intensity of gradient magnetic separation, the magnetic field intensity of the first separation is 900 Gs, and the magnetic field intensity of the second separation is 1300 Gs.

[0087] (2) Classification separation: The magnetic separation rough concentrate is subjected to classification treatment by a hydrocyclone to separate the fine-grained high-sulfur iron concentrate of -0.074 mm;

[0088] The working pressure during the classification process is 0.15 MPa, and the feed concentration is 30%.

[0089] (3) Selective regrinding: The +0.074 mm coarse-grained product is combined with the magnetic separation tailings and regrinded to -0.074 mm accounting for 75% under the condition of a grinding concentration of 60%;

[0090] During the selective regrinding process, the grinding medium is steel balls with a diameter Φ of 12 mm.

[0091] (4) Lead preferential flotation: Using L-cysteine derivative (LCYD) as the sphalerite depressant and benzothiazole mercaptan collector (BTT) as the galena collector, lead flotation is carried out under the condition of pH 9.0 to obtain lead concentrate;

[0092] Based on the pulp mass, during the lead flotation process, the dosage of the sphalerite depressant LCYD is 150 g / t; the dosage of the galena collector BTT is 40 g / t.

[0093] (5) Zinc flotation: The tailings of lead flotation use graphene quantum dot-modified copper complex (GQD-Cu) as the sphalerite activator and N,N-dimethyl-3-mercaptopropionamide (DMMPA) as the zinc mineral collector, and zinc flotation is carried out under the condition of pH 6.0 to obtain zinc concentrate.

[0094] Based on the pulp mass, during the zinc flotation process, the dosage of the sphalerite activator GQD-Cu is 20 g / t, and the dosage of the zinc mineral collector DMMPA is 50 g / t.

[0095] Example 2

[0096] This example provides a method for synergistic separation of lead-zinc sulfide ore by magnetic separation-flotation, and the difference from Example 1 is only that:

[0097] (1) Gradient magnetic separation pre-concentration: The raw ore is a certain lead-zinc ore in Guangxi (Pb 1.85%, Zn 2.91%), and the raw ore is crushed to -2 mm and then ball milled to -0.074 mm accounting for 70%;

[0098] Among the magnetic field intensities of the gradient magnetic separation, the first-selection magnetic field intensity is 850 Gs, and the second-selection magnetic field intensity is 1400 Gs.

[0099] (5) Zinc flotation: Based on the pulp mass, during the zinc flotation process, the dosage of the sphalerite activator GQD-Cu is 25 g / t.

[0100] Comparative Example 1

[0101] This comparative example provides a method for synergistic separation of lead-zinc sulfide ore by magnetic separation-flotation, and the difference from Example 1 is only that:

[0102] Lead flotation: Ethyl thionocarbamate is used as the collector for lead flotation, with a dosage of 50 g / t; Lime is used as the depressant for sphalerite, with a dosage of 100 g / t.

[0103] Comparative Example 2

[0104] This comparative example provides a method for separating lead-zinc sulfide ore, which adopts the method as Figure 2 shown. The difference from Example 1 is only that:

[0105] Gradient magnetic separation is not adopted;

[0106] Lead flotation: Ethyl thionocarbamate is used as the collector for lead flotation, with a dosage of 50 g / t; The depressant for sphalerite is 75 g / t of xanthate + 25 g / t of ethyl thionocarbamate.

[0107] Test Example 1

[0108] In this test example, the lead concentrate grade, zinc concentrate grade, sulfur content in iron concentrate, lead recovery rate and zinc recovery rate obtained from Example 1-X and Comparative Example 1-X are respectively detected. Among them, lead and zinc adopt chemical titration methods, referring to GB / T8152.1-2006; Zinc adopts chemical titration method, referring to GB / T8151.1-2012, and iron-sulfur concentrate refers to the national standard GBT2462-1996.

[0109] The summary of relevant test results is shown in Table 1.

[0110] Data summary of Table 1

[0111]

[0112]

[0113] In summary, the separation method of lead-zinc sulfide ore provided by the embodiment of the present invention realizes the efficient separation of lead-zinc sulfide ore through gradient magnetic separation combined with a new type of high-efficiency flotation reagent system. Among them, the obtained lead concentrate grade ≥ 21%, sulfur content ≤ 0.18%; Zinc concentrate grade ≥ 44%, sulfur content ≤ 0.33%; Lead recovery rate ≥ 65.29%, zinc recovery rate ≥ 85.61%. Compared with the traditional process, the grade of lead-zinc concentrate has increased by 2%-4%, the recovery rate has increased by 4%-6%, and at the same time, the reagent consumption has been significantly reduced. It has the advantages of simple process flow, strong adaptability, environmental friendliness, etc., and is especially suitable for the industrial separation of high-sulfur complex lead-zinc ore.

[0114] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for synergistic magnetic separation - flotation separation of lead - zinc sulfide ore, characterized in that, The method includes the following process: The raw ore is subjected to grinding and then gradient magnetic separation for pre-concentration to obtain magnetic separation rough concentrate and magnetic separation tailings. Among them, the magnetic field intensity of the gradient magnetic separation is 800 Gs - 1500 Gs; The magnetic separation rough concentrate is subjected to classification to obtain a coarse-grained product and a fine-grained product; The coarse-grained product is combined with the magnetic separation tailings for selective regrinding; After the selectively re-ground minerals are successively subjected to lead flotation and zinc flotation, the separation of lead-zinc sulfide ores is achieved; Among them, a sphalerite depressant and a galena collector are added for the lead flotation; a zinc ore activator and a zinc mineral collector are added for the zinc flotation.

2. The method according to claim 1, wherein Among the magnetic field intensities of the gradient magnetic separation, the magnetic field intensity of the first separation is 800 Gs - 1000 Gs, and the magnetic field intensity of the second separation is 1200 Gs - 1500 Gs; And / or, the working pressure in the classification process is 0.12 MPa - 0.18 MPa, and the feed concentration is 25% - 35%; the particle size of the coarse-grained product is +0.074 mm, and the particle size of the fine-grained product is -0.074 mm; among them, the fine-grained product is high-sulfur iron concentrate.

3. The method according to claim 1, characterized in that During the selective regrinding process, the mineral concentration is 50% - 65%, and the diameter Φ of the grinding medium is 10 mm - 15 mm; Among the minerals after selective regrinding, the proportion of minerals with a particle size of -0.074 mm is 75% - 85%.

4. The method according to claim 1, wherein The lead flotation is carried out under the condition of pH 8.5 - 10.0; And / or, the lead flotation includes the following process: one rough selection, two cleanings, and two scavengings.

5. The method according to claim 1, characterized in that Based on the mass of the pulp, during the lead flotation process, the dosage of the sphalerite depressant is 80 g / t - 200 g / t; The sphalerite depressant is an L-cysteine derivative, and its structural general formula is HS-CH2-CH(NH2)-CO-X, where X is selected from a carboxyl group, an ester group, or an amide group.

6. The method according to claim 1, wherein Based on the mass of the pulp, during the lead flotation process, the dosage of the galena collector is 25 g / t - 60 g / t; The galena collector is a benzothiazole mercaptan collector, and its structural general formula is C7H4NS2-R, where R is selected from C1 - C4 alkyl groups.

7. The method according to claim 1, wherein Using the tailings of the lead flotation as raw materials for zinc flotation, the zinc flotation is carried out under the condition of pH 5.0 - 6.5; And / or, the zinc flotation includes the following process: one rough selection, three cleanings, and two scavengings.

8. The method according to claim 1, wherein The sphalerite activator is selected from at least one of copper sulfate, copper chloride, sodium sulfide, lead nitrate, lead acetate, and a copper complex modified by graphene quantum dots; among them, the copper complex is preferably a copper-ethylenediaminetetraacetic acid complex; Based on the mass of the pulp, during the zinc flotation process, the dosage of the sphalerite activator is 10 g / t - 30 g / t.

9. The method according to claim 1, wherein Based on the mass of the pulp, during the zinc flotation process, the dosage of the zinc mineral collector is 30 g / t - 80 g / t; the zinc mineral collector is N,N-dimethyl-3-mercaptopropionamide.

10. The method according to claim 1, characterized in that, After the separation of the lead-zinc sulfide ores, the grade of the lead concentrate ≥ 21%, and the grade of the zinc concentrate ≥ 44%; the lead recovery rate ≥ 65.29%, and the zinc recovery rate ≥ 85.61%.

Images