Beneficiation method for copper-containing high-sulfur magnetite ore

Abstract

The invention discloses a beneficiation method of copper-containing high-sulfur magnetite ore, and relates to the technical field of beneficiation, and the beneficiation method comprises the following specific steps: S1, crushing and pre-selecting to remove large particles; s2, intensively separating out iron ore concentrate in a magnetic separation section; s3, undersize products in the step S1 and magnetic separation tailings in the step S2 are subjected to modification pretreatment through sodium silicate-polyepoxysuccinic acid; the sodium silicate-polyepoxysuccinic acid is formed by compounding sodium silicate and polyepoxysuccinic acid, and the addition amount of PESA is 0.2-0.4 kg / t; the modulus of sodium silicate is 2.8-3.2, the content of Na2O is greater than or equal to 8.5%, and the content of SiO2 is greater than or equal to 26.5%; the addition amount is 1.2 to 2.5 kg / t; s4, concentration and desliming-flotation are combined, and copper-sulfur bulk concentrate is obtained; and S5, copper-sulfur separation. A better separation effect can be achieved, and the obtaining amount of grade copper is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of ore dressing, and particularly to a method for dressing copper-bearing high-sulfur magnetite ore. Background Art

[0002] Ore dressing is a process of separating useful minerals from gangue minerals and separating various symbiotic (associated) useful minerals from each other as much as possible, removing or reducing harmful impurities according to the physical and chemical properties of different minerals in the ore after crushing and grinding the ore, and adopting methods such as gravity separation, flotation, magnetic separation, and electrostatic separation to obtain raw materials required for smelting or other industries.

[0003] Minerals are divided into strongly magnetic minerals, weakly magnetic minerals, and non-magnetic minerals. Magnetic separation is a method for separating minerals in an uneven magnetic field according to the magnetic differences of minerals in the ore. Magnetic separation is mostly used for magnetic ferrous metal oxide minerals such as magnetite, vanadium-titanium magnetite, hematite, and ilmenite, and is also used for the dressing of pyrrhotite; the iron minerals in iron ore are mainly magnetite, and a small amount of chalcopyrite and pyrite that can be comprehensively recovered are associated; due to the too low copper grade, the recovery is often not considered in the mining process, which causes a great waste of copper resources to a large extent.

[0004] For example, in Chinese Patent, Application No. CN202110554147.5, a method for dressing copper-bearing high-sulfur magnetite ore is used for the dressing of copper-bearing high-sulfur magnetite ore with an original ore iron grade between 30% and 40%, a sulfur content between 1.5% and 3.0%, and a copper grade between 0.04% and 0.10%. Through the surface chemical regulation of thickening and desliming, the ultrafine slime has a high specific surface area, preferentially adsorbs the collector AT-608 to form a "reagent shielding layer", and then after removing the slime below 20μm, the dosage of flotation reagents is reduced, and the copper recovery rate is improved; while reducing the amount of ore entering the mill and the grinding energy consumption, this invention reduces the loss of valuable elements such as copper and sulfur, eliminates the adverse effects of coarse-grained tailings on flotation cell jamming and fine-grained consumption of reagents in bulk flotation and the difficulty in meeting the standards of copper-sulfur concentrates, and solves the problem that ultrafine particles lead to poor slurry fluidity when improving the tailings filling concentration.

[0005] However, when the mineral dissemination size increases, the proportion of sulfur and copper minerals in the coarse fraction increases, and the slag screen cannot effectively intercept them, resulting in waste of sulfur and copper in the end. Summary of the Invention

[0006] By providing a method for dressing copper-bearing high-sulfur magnetite ore, the embodiments of the present application solve the problem in the prior art that when the mineral dissemination size increases, the proportion of sulfur and copper minerals in the coarse fraction increases, resulting in waste of sulfur and copper, and achieve a better separation effect.

[0007] The embodiments of the present application provide a method for dressing copper-bearing high-sulfur magnetite ore, and the specific steps include: S1. Pre-crushing and pre-selection to remove large particles; S2. Magnetic separation section for enhanced separation of iron concentrate; S3. Use sodium silicate - polyepoxysuccinic acid (PESA) modification pretreatment for the undersize product of step S1 and the magnetic separation tailings in S2; Sodium silicate - polyepoxysuccinic acid is the compound use of sodium silicate and polyepoxysuccinic acid (PESA). The addition amount of PESA is 0.2 - 0.4 kg / t; the modulus of sodium silicate is 2.8 - 3.2, the content of Na2O ≥ 8.5%, the content of SiO2 ≥ 26.5%; the addition amount is 1.2 - 2.5 kg / t; S4. Combined use of thickening, de - sludging and flotation to obtain copper - sulfur bulk concentrate; S5. Copper - sulfur separation.

[0008] Furthermore, it is used for the beneficiation of copper - bearing high - sulfur magnetite ore with the original ore having an iron grade between 40% - 52%, a sulfur grade between 1.4% - 2.8%, and a copper grade between 3.2% - 5.8%.

[0009] Furthermore, the pH condition for the sodium silicate - polyepoxysuccinic acid modification pretreatment is 4.5 - 9.5.

[0010] Furthermore, the sodium silicate - polyepoxysuccinic acid modification pretreatment includes two ion selections, and the ions are calcium ions and aluminum ions commonly found in beneficiation.

[0011] Furthermore, the first ion selection is specifically: adjust the pH in the agitation tank to 4.5 using sulfuric acid, react for 8 - 12 min, and then add 5 g / t of APAM.

[0012] Furthermore, for the first ion selection, adjust the pH in the agitation tank to 5 using sulfuric acid, react for 8 - 12 min, and add low - modulus sodium silicate and short - chain PESA.

[0013] Furthermore, after the first ion selection, adjust the pH of the liquid to 7.5 using lime milk and add a collector.

[0014] Furthermore, for the second ion selection, adjust the pH to 9.5 using lime milk, and then add high - modulus sodium silicate and long - chain PESA.

[0015] Furthermore, the modulus of the low - modulus sodium silicate is 2.8, and the chain length of the short - chain PESA is 3000 - 5000.

[0016] Furthermore, the modulus of the high - modulus sodium silicate is 3.2, and the chain length of the long - chain PESA is 8000 - 12000.

[0017] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: First, sodium silicate preferentially adsorbs on the surface of fine slime to form a hydrophilic film, reducing the coverage of fine slime on chalcopyrite; sodium silicate disperses the fine slime in the pulp, reduces the viscosity, improves the bubble-mineral collision efficiency, and promotes separation; sodium silicate promotes the removal of ultrafine slime, reduces the yield stress of the filling body, and sodium silicate inhibits the ineffective adsorption of fine slime on the collector (AT-608), releases the active sites of the reagent, and increases the effect of the collector.

[0018] Second, through the synergistic effect of PESA and sodium silicate, a molecular-level anti-hard water barrier is formed to form a core-shell structure, and the wettability is regulated to promote separation, and the rheology-adsorption synergistic effect is utilized; the chelating function of PESA (anti-Ca 2+ ) is complementary to the electrostatic regulation (dissociation strengthening) of sodium silicate to form a "chelating-dispersing-hydrophobic" trinity mechanism; by orienting and modifying the surface of chalcopyrite with epoxy groups, differential desorption of sulfides is achieved; double dispersion reduces the pulp viscosity to 45 mPa·s, and the flotation rate constant k value breaks through 2.3 min -1 to reach the high-efficiency separation threshold.

[0019] Third, through staged pH regulation (4.5 → 9.5), Al is preferentially precipitated 3+ (generating crystalline Al(OH)3), eliminating the competitive consumption of PESA by excessive Al 3+ Then, under alkaline conditions of PESA and sodium silicate, sodium silicate and PESA form an anti-hard water core-shell structure to further chelate residual Ca 2+ to prevent it from forming CaSiO3 precipitate with sodium silicate.

[0020] Fourth, by combining the use of sodium silicate with different moduli and PESA with different chain lengths, targeted dissociation of coarse particle sizes and deep separation of fine particle sizes can be achieved, the anti-interference ability can be improved, and a higher-grade copper ore can be obtained. Detailed implementation manners

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs; the terms used in the description of the present invention in this specification are only for the purpose of describing specific implementation manners, and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] It should be noted that the units kg / t and g / t represent the mass ratio of a certain component in the whole material to be processed. When the material to be processed is raw ore, kg / t (g / t) represents the addition amount of a certain component per ton of raw ore. When the material to be processed is pulp, kg / t (g / t) represents the addition amount of a certain component per ton of pulp. When the material to be processed is mixed concentrate, kg / t (g / t) represents the addition amount of a certain component per ton of mixed concentrate.

[0023] Example 1: A beneficiation method for copper-bearing high-sulfur magnetite ore of the present application is used for beneficiating copper-bearing high-sulfur magnetite ore with an iron grade of 40%-52%, a sulfur grade of 1.4%-2.8%, and a copper grade of 3.2%-5.8% in the raw ore; S1. Crushing and pre-selection: The raw ore is crushed to 12 mm, and heavy magnetic pre-selection is carried out to discard tailings. The pre-selected tailings are classified by a 1 mm straight-line screen. The oversize product (7-10%) is used as building materials; the undersize product is combined with the tailings of the subsequent weak magnetic separation and enters S3 for pretreatment; S2. Strengthening the magnetic separation section: The pre-selected rough concentrate is ground and magnetically separated in two stages (the first stage is ground to 200 mesh at 55%, and the second stage is ground to 200 mesh at 75%). Three times of weak magnetic separation (magnetic field intensity 0.20 T) to obtain iron concentrate (TFe≥65%); S3. Pretreatment with sodium silicate modification; The undersize product in S1 and the magnetic separation tailings in S2 (containing Cu 3.2%-5.8%, S 1.4%-2.8%) enter a Φ6m agitation tank, sodium silicate solution is added, and lime is added simultaneously to adjust the pH to 9.5. The pulp is intercepted by a straight-line vibrating screen (1 mm) to remove coarse slag; The modulus of sodium silicate is 2.8-3.2, the Na2O content is ≥8.5%, and the SiO2 content is ≥26.5%; the addition amount is 1.2-2.5 kg / t; it should be noted that the unit kg / t used in this step represents the addition amount per ton of raw ore. The addition amount of sodium silicate of 1.2-2.5 kg / t means that 1.2-2.5 kg of sodium silicate is added per 1 ton of raw ore; S4. Combined use of thickening, de-sludging and flotation: The undersize pulp enters a high-efficiency thickener (adding 15 g / t of APAM), and the underflow enters a flotation machine for one rough selection, one fine selection, and two scavenging selections. AT-608 is used as a collector and No. 2 oil is used as a foaming agent. The dosage of AT-608 is 60 g / t, and the dosage of the foaming agent No. 2 oil is 25 g / t; the dosage of the collector and foaming agent in the first scavenging selection: the dosage of AT-608 is 30 g / t, and the dosage of the foaming agent No. 2 oil is 15 g / t; the dosage of the collector and foaming agent in the second scavenging selection: the dosage of AT-608 is 30 g / t, and the dosage of the foaming agent No. 2 oil is 15 g / t; to obtain copper-sulfur mixed concentrate (Cu: 8.9-12.2%, S: 5.6-9.1%); in this step, the unit g / t represents the addition amount per ton of pulp. The dosage of AT-608 of 60 g / t means that 60 g of AT-608 is added per ton of pulp; S5. Copper-sulfur separation: The mixed concentrate is reground to 85% passing 200 mesh, and lime is added to inhibit pyrite. Separation of copper concentrate (Cu≥19%, S≤25%) and sulfur concentrate (S≥45%) is carried out, including one roughing, two cleanings, and two scavengings. Lime dosage: 3000 g / t for roughing, 1500 g / t for the first cleaning, 750 g / t for the second cleaning, 1500 g / t for the first scavenging, and 1500 g / t for the second scavenging. In this step, the unit g / t represents the addition amount per ton of the mixed concentrate. A lime dosage of 3000 g / t means adding 3000 g of lime per ton of the mixed concentrate.

[0024] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: SiO(OH) generated by the hydrolysis of sodium silicate 3- makes the Zeta potential on the surface of copper-sulfur minerals change from -25 mV to -40 mV, weakens the negative charge on the surface of quartz (Zeta changes from -15 to -10 mV), resulting in an increase in the electrostatic repulsion between chalcopyrite and quartz (ΔZeta = 30 mV), promotes the dissociation of coarse-grained inclusions, improves the dissociation degree. Coarse-grained locked particles (chalcopyrite - quartz) that were not completely dissociated in the grinding section are secondarily dissociated due to surface charge repulsion, and the proportion of copper-sulfur in the coarse-grained fraction (+1 mm) decreases. Sodium silicate (with a particle size of 2 - 5 nm) forms an adsorption layer on the mineral surface, and through steric hindrance effect, it prevents the physical entrapment of copper-sulfur minerals and gangue in the coarse-grained fraction. Sodium silicate is preferentially adsorbed on the surface of slime, forming a hydrophilic film, reducing the coverage of slime on chalcopyrite. Sodium silicate disperses the slime in the pulp, reduces the viscosity, improves the bubble-mineral collision efficiency, and promotes separation. Sodium silicate promotes the removal of ultra-fine slime, reduces the yield stress of the filling body, inhibits the ineffective adsorption of slime on the collector (AT-608), releases the active sites of the reagent, and increases the effect of the collector.

[0025] Group experiments were carried out. The iron grade of the raw ore in the experiment was 40%, the sulfur grade was 2.2%, and the copper grade was 4.6%. The grouping is shown in Table 1. Table 1

[0026] Zeta potential and surface charge analysis were detected. The surface potential of minerals was measured using a Zeta potential instrument (Malvern Zetasizer Nano). The experimental results are shown in Table 2. Table 2

[0027] Flotation kinetics test was carried out in a 1.5 L flotation cell. In the control group and the experimental group (1.8 kg / t sodium silicate), the pH was maintained at 9.5 (adjusted with lime), the dosage of AT-608 was 80 g / t, and the copper recovery rates at different time points (0 - 5 min) were recorded to fit the flotation rate constant (k value); the results are shown in Table 3; Table 3

[0028] The +1 mm coarse particle size was separated by screening method, and the monomer dissociation degree of copper sulfide minerals was measured by MLA (Mineral Liberation Analyzer), and the results are shown in Table 4; Table 4

[0029] Example 2: In the above example, through the charge regulation and dispersion effect of sodium silicate, the problems of insufficient dissociation of coarse particle size, serious interference of fine slime, and poor flotation kinetics were solved. However, when the concentration of Ca 2+ / Mg 2+ in water > 200 mg / L, sodium silicate (SiO(OH) 3- ) reacts with Ca 2+ to form CaSiO3 precipitate, resulting in the coverage of the surface of copper sulfide minerals and affecting the effect of sodium silicate. Therefore, on the basis of Example 1, further improvements were made.

[0030] In the sodium silicate modification pretreatment in step S3, sodium silicate and polyepoxysuccinic acid (PESA) were used in combination, and the addition amount of PESA was 0.2 - 0.4 kg / t; that is, 0.2 - 0.4 t of PESA was added per ton of raw ore.

[0031] Sodium silicate and polyepoxysuccinic acid were premixed and stirred evenly before being added to the stirring tank.

[0032] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: Through the synergistic effect of PESA and sodium silicate, a molecular-level anti-hard water barrier is formed to form a core-shell structure, and the wettability is regulated to promote separation, and rheology-adsorption synergistic enhancement is utilized; the chelating function of PESA (anti-Ca 2+ ) and the electrostatic regulation of sodium silicate (dissociation strengthening) are complementary to form a "chelating-dispersing-hydrophobic" three-in-one action mechanism; the surface of chalcopyrite is directionally modified by epoxy groups to achieve differential desorption of sulfides; double dispersion reduces the pulp viscosity to 45 mPa·s, and the flotation rate constant k value breaks through 2.3 min -1 , reaching the high-efficiency separation threshold.

[0033] The chemical formula of PESA is (C3H4O4) n, the main chain consists of epoxy succinic acid repeating units, containing epoxy groups (-O-) and carboxylic acid groups (-COOH). Carboxylic acid groups: Chelate Ca in water through ionic bonds (-COO - …Ca 2+ ) to form a stable five-membered ring complex (bond energy ≈ 200 kJ / mol); epoxy groups provide the flexibility of the molecular chain and combine with the silanol groups (Si-OH) of sodium silicate through hydrogen bonds (-O-…H-O-Si). 2+ , forming a stable five-membered ring complex (bond energy ≈ 200 kJ / mol); epoxy groups provide the flexibility of the molecular chain and combine with the silanol groups (Si-OH) of sodium silicate through hydrogen bonds (-O-…H-O-Si).

[0034] The carboxylic acid groups of PESA and the SiO(OH) of sodium silicate 3- form a COO - …H-O-Si bridging structure through hydrogen bond-ion bond hybridization; the oxygen atom of the epoxy group forms an O-H-O hydrogen bond (bond length ≈ 1.8 Å, bond energy ≈ 25 kJ / mol) with the hydrogen of the silanol group; the flexible long chain of PESA (molecular weight 2000 - 5000) wraps the sodium silicate colloidal particles (particle size 2 - 5 nm) to form a core-shell structure, preventing Ca 2+ from contacting the active sites of sodium silicate.

[0035] PESA and sodium silicate form a three-dimensional network structure through hydrophobic interaction and electrostatic complementarity: the hydrophobic segment (epoxy group region) of PESA combines with the hydrophobic surface (Si-O-Si) of sodium silicate through van der Waals forces (≈ 5 kJ / mol); the electrostatic attraction (≈ 15 kJ / mol) between the carboxylic acid groups and the silanol groups maintains the structural stability, enabling PESA and sodium silicate to drive self-assembly; the complex covers the surface of copper sulfide minerals (chalcopyrite, pyrite) through multi-point anchoring (each molecule contains 3 - 5 adsorption sites), increasing the adsorption energy density; the three-dimensional network of the PESA-sodium silicate complex forms a shear-thinning structure in the pulp; when static, the network cross-links (viscosity ≈ 150 mPa·s), preventing particle sedimentation; under high shear force (G > 300 s -1 ), the network dissociates (viscosity ≈ 50 mPa·s), improving the bubble-mineral collision efficiency.

[0036] The epoxy group region of PESA is hydrophobic and the carboxylic acid group region is hydrophilic. Cooperating with the charge regulation of sodium silicate, it realizes sorting selectivity, enabling the complex to form hydrophilic-hydrophobic alternating microdomains on the surface of chalcopyrite, while the surface of pyrite remains uniformly hydrophilic.

[0037] PESA chelates 90% of Ca 2+ (complex formation constant logK = 8.2), and the remaining Ca 2+ is physically shielded by the sodium silicate-PESA core-shell structure; the Ca 2+ concentration tolerance is increased from 210 mg / L (single sodium silicate) to 830 mg / L (PESA-sodium silicate).

[0038] The flexible chain of PESA compensates for the brittleness of the rigid structure of sodium silicate, forming an adaptive adsorption layer on the mineral surface, and the anti-mechanical shear peeling ability is increased by 3 times; the complex reduces the adhesion energy barrier between chalcopyrite minerals and bubbles (from 50 kT → 25 kT), and the mineralization rate is increased by 2 times.

[0039] Group experiments were carried out on Example 2. The raw ore had an iron grade of 47%, a sulfur grade of 2.8%, and a copper grade of 3.4% in the experiment; the grouping is shown in Table 5; Table 5

[0040] The Zeta potential and adsorption amount on the surface of chalcopyrite were measured, and the results are shown in Table 6; Table 6

[0041] A contact angle measuring instrument was used to analyze the wettability difference between chalcopyrite and pyrite at different dosages of PESA; the results are shown in Table 7; Table 7

[0042] The pulp viscosity (GB10247-88, shear rate 100s -1 ) and the bubble mineralization frequency (high-speed camera) were measured at different dosages of PESA, and the results are shown in Table 8; Table 8

[0043] Finally, the copper recovery was detected, and the results are shown in Table 9; Table 9

[0044] Example 3: In Example 2, through the synergistic effect of PESA and sodium silicate, a molecular-level anti-hard water barrier is formed to form a core-shell structure, and the wettability is regulated to promote separation. Using rheology-adsorption synergistic enhancement, the problem that the reaction of Ca 2+ generates CaSiO3 precipitation, resulting in the coverage of the surface of chalcopyrite minerals and affecting the effect of sodium silicate, is solved. However, in high-hardness water quality, polyvalent cations (Ca 2+ +Al 3+ ) coexist. Al 3+ forms an Al-PESA complex (stability constant logK = 12.5) with PESA preferentially, consuming the chelating ability of PESA. Residual Ca 2+ still generates CaSiO3 precipitation with sodium silicate. To solve the problem of the reduction of the effect of sodium silicate caused by a large amount of metal ions, further improvement was made on the basis of Example 2.

[0045] In the sodium silicate modification pretreatment in step S3, after the magnetic separation tailings enter the stirring tank, two ion selections are carried out; First, the first ion selection is carried out. Then, the pH in the stirring tank is adjusted to 4.5 using sulfuric acid, and the reaction is carried out at 25 °C for 8 - 12 min (stirring intensity: 200 s -1 ), then 5 g / t of APAM is added, and after solid-liquid separation, part of the aluminum ions are removed. The liquid undergoes the second ion selection. The pH is adjusted to 9.5 using lime milk, and then a mixed solution of sodium silicate and polyepoxysuccinic acid is added, and stirred for 5 - 8 min at 300 s -1 to remove part of the calcium ions.

[0046] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: By regulating the pH in stages (4.5 → 9.5), Al 3+ is preferentially precipitated (generating crystalline Al(OH)3), and the excessive Al 3+ is eliminated to compete and consume PESA. Then, under alkaline conditions of PESA and sodium silicate, sodium silicate and PESA form a hard water-resistant core-shell structure to further chelate the residual Ca 2+ to prevent it from forming CaSiO3 precipitation with sodium silicate.

[0047] Al 3+ and Ca 2+ are treated step by step to avoid competitive complexation, which is applicable to the beneficiation process with high-hardness water quality or a large amount of free metal ions. After removing Al 3+ step by step, PESA effectively chelates Ca 2+ to avoid excessive addition of reagents caused by Al 3+ competition, avoid the formation of CaSiO3 precipitation, reduce the loss of sodium silicate, and reduce the treatment cost per ton of ore.

[0048] Through grouped experiments, based on experiment 5, further experiments are carried out to test the effect of regulating the pH in stages. The removal results of Al 3+ are shown in Table 10, Table 10

[0049] The beneficiation results are shown in Table 11; Table 11

[0050] Example 4: In Example 3, through the reconstruction of chemical cleaning priority and the spatio-temporal decoupling of the process, the copper recovery rate was achieved in a complex system of polyvalent cations, solving the problem of competition among multiple metal ions. It was found in actual use that although metal ions would reduce the effect of sodium silicate, they could strengthen the separation of pyrite and chalcopyrite. Therefore, in order to improve its practical application ability, further improvements were made on the basis of Example 3.

[0051] The first ion selection: Adjust the pH in the stirring tank to 5 using sulfuric acid, react at 25 °C for 8 - 12 min (stirring intensity: 200 s -1 ), add sodium silicate with a modulus of 2.8, dosage 0.5 kg / t, short-chain PESA (3000 - 5000), dosage 0.2 kg / t, perform solid-liquid separation to remove part of the aluminum ions, adjust the pH of the liquid to 7.5 using lime milk, add a collector (AT-608) with a dosage of 30 g / t, and then perform the second ion selection. Continue to adjust the pH to 9.5 using lime milk, add sodium silicate with a modulus of 3.2, dosage 1.2 kg / t, long-chain PESA (8000 - 12000) with a dosage of 0.3 kg / t, and the temperature is 40 - 45 °C.

[0052] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: By using a combination of sodium silicate with different moduli and PESA with different chain lengths, it is possible to achieve targeted dissociation of coarse-grained particles, deep sorting of fine-grained particles, improve the anti-interference ability, and obtain copper ore with higher grade.

[0053] Low-modulus sodium silicate rapidly disperses the coarse-grained pulp, and short-chain PESA preferentially chelates Al 3+ , releasing the surface active sites of sulfide copper minerals. Low-modulus sodium silicate (SiO2 / Na2O ≈ 2.8) hydrolyzes to generate more oligomeric silicic acid (Si2O5 2- ) under weakly acidic (pH = 5) conditions, and forms an Al-Si complex (AlO6-Si2O5) through electrostatic adsorption with Al 3+ , accelerating the precipitation of Al(OH)3; High-modulus sodium silicate forms a dense hydrophilic film to inhibit pyrite, hydrolyzes to generate more SiO(OH)3 - under strongly alkaline conditions, enhances the negative charge on the mineral surface, further enlarges the potential difference with gangue to separate sulfide copper ore, and long-chain PESA deeply chelates residual Ca 2+ to form a more stable Ca-PESA complex. At the same time, the flexible structure of the long chain enhances the steric hindrance and prevents Ca 2+Contact with sodium silicate; in the first ion selection, low-modulus sodium silicate and short-chain PESA are used. Through high dispersibility and rapid chelation, coarse-grained chalcopyrite minerals are preferentially dissociated. In the second ion selection, high-modulus sodium silicate and long-chain PESA are used. Through strong inhibition and long-term chelation, the hetero-aggregation of fine-grained pyrite and chalcopyrite is blocked.

[0054] Although the flotation of chalcopyrite is difficult under the influence of Ca 2+ +Al 3+ , Ca 2+ as an activator can selectively activate the surface of chalcopyrite and enhance its hydrophobicity. Under neutral conditions, Ca 2+ binds to the Fe sites on the surface of chalcopyrite, exposing the Cu-S hydrophobic active sites and enhancing the adsorption efficiency of the collector; at high pH, the residual Ca 2+ reacts with sodium silicate to form CaSiO3 colloid, which coats the gangue minerals; Al 3+ forms a stable complex with PESA, strengthening the pulp dispersion. Al 3+ as an inhibitor can inhibit pyrite and gangue minerals through hydroxy complexes. Under weakly acidic conditions, Al 3+ generates complexes such as Al(OH)2 + and Al(OH)4 - , which are preferentially adsorbed on the surfaces of pyrite and quartz to form a hydrophilic layer; thus, in the presence of a large number of ions, the separation of chalcopyrite and pyrite can be achieved, and higher-grade copper concentrate can be obtained.

[0055] On the basis of Example 3, the copper recovery rate in Example 4 was detected, and the results are shown in Table 12; Table 12

[0056] 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, various changes and modifications can be made to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A beneficiation method for copper-bearing high-sulfur magnetite ore, characterized in that, The specific steps include: S1. Crushing and pre-selection to remove large particles; S2. Strengthening the separation in the magnetic separation section to obtain iron concentrate; S3. Using sodium silicate-polyepoxysuccinic acid modification pretreatment for the undersize product of step S1 and the magnetic separation tailings in S2; Sodium silicate-polyepoxysuccinic acid is a compound of sodium silicate and polyepoxysuccinic acid, and the addition amount of sodium silicate-polyepoxysuccinic acid is 0.2 - 0.4 kg / t; the modulus of sodium silicate is 2.8 - 3.2, the Na2O content ≥ 8.5%, the SiO2 content ≥ 26.5%; the addition amount is 1.2 - 2.5 kg / t; S4. Combining thickening, de-sludging and flotation to obtain copper-sulfur bulk concentrate; S5. Copper-sulfur separation.

2. The beneficiation method of a copper-containing high-sulfur magnetite ore according to claim 1, characterized in that, It is used for the beneficiation of copper-bearing high-sulfur magnetite ores with the iron grade of the raw ore between 40% and 52%, the sulfur grade between 1.4% and 2.8%, and the copper grade between 3.2% and 5.8%.

3. The beneficiation method of a copper-containing high-sulfur magnetite ore according to claim 1, characterized in that, The pH condition for the sodium silicate-polyepoxysuccinic acid modification pretreatment is 4.5 - 9.

5.

4. The beneficiation method of a copper-containing high-sulfur magnetite ore as described in claim 1, characterized in that, The sodium silicate-polyepoxysuccinic acid modification pretreatment includes two ion selections, and the ions are calcium ions and aluminum ions common in beneficiation.

5. The beneficiation method of a copper-containing high-sulfur magnetite ore according to claim 4, characterized in that, The first ion selection is specifically: adjusting the pH in the agitation tank to 4.5 with sulfuric acid, reacting for 8 - 12 min, and then adding 5 g / t of APAM.

6. The beneficiation method of a copper-containing high-sulfur magnetite ore as claimed in claim 4, wherein, For the first ion selection, adjusting the pH in the agitation tank to 5 with sulfuric acid, reacting for 8 - 12 min, and adding low-modulus sodium silicate and short-chain sodium silicate-polyepoxysuccinic acid.

7. The beneficiation method of a copper-containing high-sulfur magnetite ore as described in claim 6, characterized in that, After the first ion selection, adjusting the pH of the liquid to 7.5 with lime milk and adding a collector.

8. The beneficiation method of a copper-containing high-sulfur magnetite ore according to claim 1, characterized in that, For the second ion selection, adjusting the pH to 9.5 with lime milk, and then adding high-modulus sodium silicate and long-chain sodium silicate-polyepoxysuccinic acid.

9. The beneficiation method of a copper-containing high-sulfur magnetite ore as described in claim 6, wherein The modulus of the low-modulus sodium silicate is 2.8, and the chain length of the short-chain sodium silicate-polyepoxysuccinic acid is 3000 - 5000.

10. The beneficiation method of a copper-containing high-sulfur magnetite ore according to claim 8, characterized in that, The modulus of the high-modulus sodium silicate is 3.2, and the chain length of the long-chain sodium silicate-polyepoxysuccinic acid is 8000 - 12000.

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