A flotation depressant and flotation method for recovering copper from magnetically separated iron tailings

Abstract

This invention relates to a flotation depressant and flotation method for recovering copper from magnetically separated iron tailings, specifically in the field of mineral flotation technology. The flotation depressant comprises: sulfonated modified tannin, sodium cyanurate, carboxymethyl chitosan, and carbonates. The flotation depressant provided by this invention, through the synergistic effect of its components, achieves highly efficient selective inhibition of pyrite at a pulp pH of 8-9, while having no significant inhibitory effect on chalcopyrite. It is suitable for low-grade, fine-grained, disseminated magnetically separated iron tailings, yielding copper concentrate with a Cu grade ≥19.22% and a recovery rate ≥72.50%. This invention solves problems such as foaming and stickiness, equipment scaling, and difficulty in meeting alkalinity standards in traditional high-alkali lime processes. It has advantages such as low alkali content, high efficiency, and environmental friendliness, and has broad prospects for industrial application.

Description

Technical Field

[0001] This invention relates to the field of mineral flotation technology, specifically to a flotation inhibitor and flotation method for recovering copper from magnetically separated iron tailings, and particularly to a flotation scenario for low-grade iron tailings with a high proportion of low-grade, fine-grained, and micro-fine-grained copper minerals that can replace the lime high-alkali copper-sulfur separation process. Background Technology

[0002] Currently, the mainstream process for copper-sulfur separation in magnetic iron tailings is lime high-alkali sulfur suppression and copper flotation, but there are still many problems that need to be solved:

[0003] ① The amount of lime used is large, the pH of the slurry is usually >12, the foam is sticky, and the concentrate is difficult to filter;

[0004] ② Severe calcium buildup in pipelines and equipment, unstable chemical dosing, and large fluctuations in production indicators;

[0005] ③ Pyrite is deeply passivated by strong alkali, and subsequent sulfur recovery requires activation with strong acid, which corrodes equipment and puts great pressure on the environment;

[0006] ④ The discharge of highly alkaline tailings is restricted, and the cost of wastewater treatment is high.

[0007] Although existing technologies use low-alkali / alkali-free inhibitors for sulfur suppression and copper floating, these inhibitors often have the following shortcomings:

[0008] ① The inhibitory capacity of a single inhibitor is insufficient and it is difficult to adapt to low-grade tailings;

[0009] ② Poor adaptability to the characteristics of magnetic separation tailings, including mud content, fine particles, and low copper and sulfur content;

[0010] ③ It has poor compatibility with on-site collector systems, making industrialization difficult.

[0011] In summary, there is an urgent need to develop a low-alkali, high-efficiency copper-sulfur separation inhibitor that can replace lime, so as to achieve efficient separation and recovery of copper and sulfur and solve the problem of high-value utilization of low-grade iron tailings resources. Summary of the Invention

[0012] In view of the problems existing in the prior art, the purpose of this invention is to provide a flotation inhibitor and flotation method for recovering copper from magnetic separation iron tailings, so as to solve the many drawbacks of lime high-alkali separation in the existing iron tailings copper-sulfur recovery process, and realize efficient and clean separation of copper and sulfur under low-alkali conditions.

[0013] To achieve this objective, the present invention adopts the following technical solution:

[0014] In a first aspect, the present invention provides a flotation depressant for recovering copper from magnetically separated iron tailings, the flotation depressant comprising:

[0015] Sulfonated modified tannin, sodium cyanurate, carboxymethyl chitosan and carbonate.

[0016] The flotation inhibitor provided by this invention achieves highly efficient and selective inhibition of pyrite at a pulp pH of 8-9 through the synergistic effect between its components, while having no significant inhibitory effect on chalcopyrite. It is suitable for low-grade, fine-grained, disseminated magnetic separation iron tailings and solves the problems of foam stickiness, equipment scaling, and difficulty in meeting the high alkali standards of tailings in traditional lime high-alkali processes. It has the advantages of low alkali, high efficiency, and environmental protection, and has broad prospects for industrial application.

[0017] As a preferred embodiment of the present invention, the flotation inhibitor comprises, by weight:

[0018] Sulfonated modified tannin 12-20 parts, sodium cyanurate 6-12 parts, carboxymethyl chitosan 1-3 parts and carbonate 6-12 parts.

[0019] As a preferred embodiment of the present invention, the degree of deacetylation of the carboxymethyl chitosan is 80-90%.

[0020] As a preferred embodiment of the present invention, the viscosity of the carboxymethyl chitosan is 50-100 mP·s.

[0021] As a preferred embodiment of the present invention, the carbonate includes one or a combination of at least two of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate.

[0022] Secondly, the present invention provides a flotation method for recovering copper from magnetically separated iron tailings, the flotation method comprising:

[0023] The tailings slurry was subjected to a first roughing process and a copper scavenging process to obtain copper-sulfur crude concentrate and tailings.

[0024] The copper-sulfur crude concentrate is regrinded and then subjected to a first cleaning process to obtain a copper-sulfur mixed concentrate.

[0025] Copper-sulfur mixed concentrate is subjected to a second roughing and a second cleaning process to obtain copper concentrate;

[0026] The tailings from the second roughing process were separated and scavenged to obtain sulfur concentrate;

[0027] The second coarse and second fine flotation filters contain flotation inhibitors as described in the first aspect.

[0028] As a preferred embodiment of the present invention, the percentage of -0.074mm particles in the tailings slurry is 55-65% of the total particle mass.

[0029] Preferably, the mass concentration of the tailings slurry is 32-38%.

[0030] As a preferred technical solution of the present invention, the flotation reagents used in the first roughing and copper scavenging include: a collector with a total dosage of 80-160 g / t and a frother with a total dosage of 10-30 g / t.

[0031] Preferably, the amount of collector used in the first roughing process is 68-72% of the total amount, and the amount of foaming agent is 78-82% of the total amount.

[0032] Preferably, the first coarse selection is performed at least once.

[0033] Preferably, the first roughing process is performed ≥2 times, and the middlings obtained from the first roughing process are sequentially returned to the previous operation.

[0034] Preferably, the copper sweeping is performed at least twice.

[0035] Preferably, the middlings obtained from the copper scavenging are sequentially returned to the previous operation.

[0036] As a preferred technical solution of the present invention, the regrinding includes: regrinding the coarse concentrate until the mass percentage of -0.037mm particles is ≥85% of all particles.

[0037] Preferably, the mass concentration of the slurry obtained from the regrinding is 26-30%.

[0038] Preferably, the first selection method includes: blank selection.

[0039] Preferably, the first selection is performed at least three times.

[0040] Preferably, the refined ore obtained from the first selection is sequentially returned to the previous operation.

[0041] As a preferred technical solution of the present invention, the pH value of the slurry is controlled to be 8-9 in the second coarse selection.

[0042] Preferably, the amount of flotation inhibitor used in the second roughing process is 100-500 g / t.

[0043] Preferably, the pH value of the slurry is controlled to be 8-9 in the second selection process.

[0044] Preferably, the amount of flotation inhibitor used in the second selection process is 20-100 g / t.

[0045] Preferably, the second selection is performed at least three times.

[0046] Preferably, the refined ore obtained from the second selection is sequentially returned to the previous operation.

[0047] Preferably, the stirring time of the slurry in a single second refining process is 2-4 minutes.

[0048] Preferably, a collector is added to the separation and scanning process, and the amount added is 1-5 g / t.

[0049] Preferably, the separation and scanning are performed at least once.

[0050] Preferably, the stirring time of the slurry in a single separation and sweep is controlled to be 2-4 minutes.

[0051] Preferably, the separation and scavenging are performed ≥2 times, and the middlings obtained from the separation and scavenging are sequentially returned to the previous operation.

[0052] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0053] (1) Low-alkali alternative to lime: High-efficiency sulfur suppression can be achieved when the slurry pH is 8-9, which completely solves the problems of sticky foam, scaling and difficult tailings treatment caused by high alkali.

[0054] (2) High selectivity: It only inhibits pyrite and has little impact on copper minerals, and is suitable for low-grade, fine-grained, muddy magnetic separation tailings.

[0055] (3) Process compatibility: It is fully compatible with existing flotation collectors, foaming agents and equipment, and can be directly industrialized without modification. Attached Figure Description

[0056] Figure 1 This is an example flowchart of a flotation method for recovering copper from magnetically separated iron tailings, provided in an embodiment of the invention.

[0057] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0058] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0059] Low-grade magnetic separation iron tailings, as a major solid waste in iron ore beneficiation, are piled up in huge quantities, not only occupying land resources but also posing potential environmental risks. While the individual grades of associated valuable elements such as copper and sulfur are low, their total amount is considerable, possessing significant comprehensive recovery value. Currently, the mainstream copper-sulfur separation process for this type of tailings is lime high-alkali sulfur suppression and copper flotation. Although this process is widely used, several problems remain to be solved: ① Large lime consumption, with slurry pH typically >12, leading to sticky foam and difficulty in concentrate filtration, affecting production efficiency; ② Severe calcium buildup in pipelines and equipment, poor reagent stability, easily causing fluctuations in production indicators and increasing equipment maintenance costs; ③ Pyrite is deeply passivated by strong alkali, requiring strong acid activation for subsequent sulfur recovery, which corrodes production equipment and increases environmental treatment pressure; ④ High-alkali tailings discharge is strictly restricted, and the supporting wastewater treatment process is complex and costly. Meanwhile, existing low-alkali / alkali-free inhibitors also have significant shortcomings, such as insufficient inhibition capacity of single inhibitors, making them difficult to adapt to low-grade tailings; poor adaptability to the characteristics of magnetic separation tailings containing mud, fine particles, and low copper and sulfur content; and weak compatibility with on-site collector systems, making industrial implementation difficult. Based on this, this invention addresses the above-mentioned process drawbacks and the defects of existing inhibitors by innovatively compounding components to prepare a highly selective inhibitory effect on sulfur minerals, stable inhibition effect, and compatible with flotation processes. This inhibitor replaces the traditional high-alkali lime sulfur suppression and copper flotation process, solving a series of problems caused by high-alkali sulfur suppression and achieving efficient separation and comprehensive recovery of copper and sulfur resources, as detailed below:

[0060] I. This embodiment provides a flotation depressant for recovering copper from magnetically separated iron tailings, the flotation depressant comprising:

[0061] Sulfonated modified tannin, sodium cyanurate, carboxymethyl chitosan and carbonate.

[0062] In this invention, sulfonated modified tannin and sodium cyanate preferentially form stable hydrophilic complexes on the surface of pyrite, significantly reducing floatability; they hardly adsorb chalcopyrite and do not affect the collector's effect. At the same time, the combination with carboxymethyl chitosan can significantly improve the dispersion of fine particles and muddy slurry, reduce non-selective entrainment, promote the uniform dispersion of sulfonated modified tannin and sodium cyanate in the slurry, ensure sufficient contact between the inhibitor and sulfur minerals, and utilize the steric hindrance effect of its molecular chains to prevent the collision and binding of sulfur mineral particles with the collector, thereby improving the concentrate grade.

[0063] In this invention, carbonates are used as system regulators to gently adjust the pH of the pulp to a low-alkali range (pH=8-9), which provides a suitable environment for the inhibitor to function, avoids the adverse effects of a high-alkali environment on copper mineral flotation, and reduces the dissolution of harmful impurities in the pulp, thereby improving the stability of the flotation process.

[0064] The flotation inhibitor comprises, by weight, the following:

[0065] Sulfonated modified tannin 12-20 parts, sodium cyanurate 6-12 parts, carboxymethyl chitosan 1-3 parts and carbonate 6-12 parts.

[0066] It should be noted that the weight of carboxymethyl chitosan in the flotation inhibitor described in this invention is based on the weight of its solids and does not include the solvent.

[0067] In this invention, the sulfonated modified tannin in the flotation inhibitor is 12-20 parts by weight, for example, 12 parts, 12.8 parts, 13.6 parts, 14.4 parts, 15.2 parts, 16 parts, 16.8 parts, 17.6 parts, 18.4 parts, 19.2 parts, or 20 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0068] In this invention, the sodium cyanate in the flotation inhibitor is 6-12 parts by weight, for example, it can be 6 parts, 6.6 parts, 7.2 parts, 7.8 parts, 8.4 parts, 9 parts, 9.6 parts, 10.2 parts, 10.8 parts, 11.4 parts or 12 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0069] In this invention, the carboxymethyl chitosan in the flotation inhibitor is 1-3 parts by weight, for example, it can be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts or 3 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0070] In this invention, the carbonate in the flotation inhibitor is 6-12 parts by weight, for example, it can be 6 parts, 6.6 parts, 7.2 parts, 7.8 parts, 8.4 parts, 9 parts, 9.6 parts, 10.2 parts, 10.8 parts, 11.4 parts or 12 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0071] In this invention, the sulfonated modified tannin can be obtained by sulfonating tannin with sulfonating agents such as sulfites according to existing technologies, such as existing technologies CN107011803A and CN1506472A, or by purchasing commercially available products.

[0072] The degree of deacetylation of the carboxymethyl chitosan is 80-90%, for example, it can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0073] The viscosity of the carboxymethyl chitosan is 50-100 mP·s, for example, it can be 50 mP·s, 55 mP·s, 60 mP·s, 65 mP·s, 70 mP·s, 75 mP·s, 80 mP·s, 85 mP·s, 90 mP·s, 95 mP·s or 100 mP·s, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0074] In this invention, the viscosity of the carboxymethyl chitosan is the viscosity of an aqueous solution of carboxymethyl chitosan (mass concentration of 1%), and the viscosity is obtained by testing at 25°C.

[0075] The carbonate includes one or a combination of at least two of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate.

[0076] II. This embodiment provides a flotation method for recovering copper from magnetically separated iron tailings. An exemplary process is as follows: Figure 1 As shown, the flotation method includes:

[0077] The tailings slurry was subjected to a first roughing process and a copper scavenging process to obtain copper-sulfur crude concentrate and tailings.

[0078] The copper-sulfur crude concentrate is regrinded and then subjected to a first cleaning process to obtain a copper-sulfur mixed concentrate.

[0079] Copper-sulfur mixed concentrate is subjected to a second roughing and a second cleaning process to obtain copper concentrate;

[0080] The tailings from the second roughing process were separated and scavenged to obtain sulfur concentrate;

[0081] The second coarse and second fine filters contain flotation inhibitors.

[0082] In this invention, the copper grade of the magnetically separated iron tailings used in the tailings slurry is ≤0.082%, and the sulfur grade is ≤0.77%.

[0083] The percentage of -0.074mm particles in the tailings slurry is 55-65% of the total particle mass, for example, it can be 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64% or 65%, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0084] In this invention, controlling the fineness of the particles in the pulp during the first roughing stage can both prevent excessive grinding from causing mud formation and ensure the initial liberation of copper minerals and gangue minerals, laying the foundation for subsequent flotation and low-alkali separation.

[0085] The mass concentration of the tailings slurry is 32-38%, for example, it can be 32%, 32.6%, 33.2%, 33.8%, 34.4%, 35%, 35.6%, 36.2%, 36.8%, 37.4% or 38%, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0086] The flotation reagents used in the first roughing and copper scavenging processes include: a collector with a total dosage of 80-160 g / t, such as 80 g / t, 88 g / t, 96 g / t, 104 g / t, 112 g / t, 120 g / t, 128 g / t, 136 g / t, 144 g / t, 152 g / t, or 160 g / t, etc.; and a frother with a total dosage of 10-30 g / t, such as 10 g / t, 12 g / t, 14 g / t, 16 g / t, 18 g / t, 20 g / t, 22 g / t, 24 g / t, 26 g / t, 28 g / t, or 30 g / t, etc., but not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0087] In this invention, the collectors and frothers used in the flotation process can be selected from commercially available products or prepared from existing technologies based on actual requirements and with reference to existing technologies. For example, the collectors can be selected from ethyl thiocyanate, ester 105, and PAC, and the frothers can be selected from No. 2 oil, MIBC (methyl isobutyl methanol), and BK204.

[0088] In this invention, the amount of collector used in flotation is designed according to the copper grade in the tailings. If the copper grade in the tailings is low, the amount of collector and frother is reduced by the basic amount to avoid excessive reagents that would reduce the concentrate grade and reduce beneficiation costs.

[0089] In the first coarse selection, the amount of collector used is 68-72% of the total amount, for example, it can be 68%, 68.4%, 68.8%, 69.2%, 69.6%, 70%, 70.4%, 70.8%, 71.2%, 71.6%, or 72%, etc., and the amount of foaming agent used is 78-82% of the total amount, for example, it can be 78%, 78.4%, 78.8%, 79.2%, 79.6%, 80%, 80.4%, 80.8%, 81.2%, 81.6%, or 82%, etc., but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0090] In this invention, the amount of flotation reagent used in the copper scavenging is the remainder of the flotation reagent used in the first roughing.

[0091] The first coarse selection is performed at least once.

[0092] In this process, the first roughing is performed ≥2 times, and the middlings obtained from the first roughing are sequentially returned to the previous operation.

[0093] The copper sweeping is performed at least twice.

[0094] The middlings obtained from copper scavenging are sequentially returned to the previous operation.

[0095] In this invention, the amount of flotation reagent used in the first roughing and copper scavenging processes is the total amount used when multiple processes are performed. The amount of flotation reagent used in a single first roughing or copper scavenging process can be reasonably configured according to actual needs.

[0096] The regrinding includes: regrinding the coarse concentrate to a mass percentage of -0.037mm particles of ≥85% of all particles, such as 85%, 86.5%, 88%, 89.5%, 91%, 92.5%, 94%, 95.5%, 97%, 98.5%, or 100%, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0097] In this invention, regrinding can effectively break the intergrowth of copper-sulfur minerals and gangue minerals, improve the degree of liberation of copper-sulfur minerals, solve the problem of poor selection indicators caused by insufficient liberation in traditional processes, and at the same time make the surface of copper minerals more fully exposed, thus providing a guarantee for efficient separation of copper and sulfur in the future.

[0098] The mass concentration of the slurry obtained from the regrinding is 26-30%, for example, it can be 26%, 26.4%, 26.8%, 27.2%, 27.6%, 28%, 28.4%, 28.8%, 29.2%, 29.6% or 30%, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0099] The first selection method includes: blank selection.

[0100] In this invention, blank selection refers to flotation performed without the addition of reagents.

[0101] In this invention, blank selection can utilize the differences in surface properties between copper-sulfur minerals and gangue minerals to remove gangue minerals from rough concentrate without reagent interference, thereby improving the basic grade of mixed concentrate. At the same time, it avoids interference from residual external reagents on subsequent low-alkali copper-sulfur separation, and the middlings return process further ensures the recovery rate of valuable elements.

[0102] The first selection process is performed at least three times.

[0103] In this process, the refined ore obtained from the first selection is sequentially returned to the previous operation.

[0104] In the second coarse selection, the pH value of the slurry is controlled to be 8-9, for example, it can be 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9 or 9, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0105] The amount of flotation inhibitor used in the second roughing process is 100-500 g / t, for example, it can be 100 g / t, 140 g / t, 180 g / t, 220 g / t, 260 g / t, 300 g / t, 340 g / t, 380 g / t, 420 g / t, 460 g / t or 500 g / t, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0106] In the second selection process, the pH value of the slurry is controlled to be 8-9, for example, it can be 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9 or 9, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0107] In the second selection process, the amount of flotation inhibitor used is 20-100 g / t, for example, it can be 20 g / t, 28 g / t, 36 g / t, 44 g / t, 52 g / t, 60 g / t, 68 g / t, 76 g / t, 84 g / t, 92 g / t or 100 g / t, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0108] The second selection process is performed at least three times.

[0109] In this process, the refined ore obtained from the second selection is sequentially returned to the previous operation.

[0110] In this second refining process, the stirring time of the slurry is controlled to be 2-4 minutes, for example, it can be 2 minutes, 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes, 3 minutes, 3.2 minutes, 3.4 minutes, 3.6 minutes, 3.8 minutes or 4 minutes, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0111] The separation and scanning process involves the addition of a collector at a concentration of 1-5 g / t, such as 1 g / t, 1.4 g / t, 1.8 g / t, 2.2 g / t, 2.6 g / t, 3 g / t, 3.4 g / t, 3.8 g / t, 4.2 g / t, 4.6 g / t, or 5 g / t, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0112] The separation and scanning process is performed at least once.

[0113] In this single separation and scavenging process, the stirring time of the slurry is controlled to be 2-4 min, for example, it can be 2 min, 2.2 min, 2.4 min, 2.6 min, 2.8 min, 3 min, 3.2 min, 3.4 min, 3.6 min, 3.8 min or 4 min, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0114] The separation and scavenging process is repeated ≥2 times, and the middlings obtained from the separation and scavenging are sequentially returned to the previous operation.

[0115] III. To illustrate the flotation effect achievable by the flotation inhibitor provided by this invention, the following example is used for explanation:

[0116] Example 1

[0117] This embodiment provides a flotation depressant for recovering copper from magnetically separated iron tailings and a specific flotation process, as follows:

[0118] Inhibitor ratio (parts by weight): 15 parts of sulfonated modified tannin (MDH25429), 9 parts of sodium cyanurate, 2 parts of carboxymethyl chitosan (degree of deacetylation of 80%, viscosity of 50 mP·s), and 9 parts of sodium carbonate.

[0119] Flotation feedstock: Chengde low-grade magnetic separation iron tailings, with a mass percentage content of 0.082% Cu and 0.77% S.

[0120] Flotation process:

[0121] ① Pulp preparation and grinding: The ore sample was ground to a particle size of -0.074mm, with 60% of the particles being of this size, and the slurry concentration was 35%.

[0122] ② Copper-sulfur flotation: 1 coarse flotation and 2 scavenging flotation. The total amount of collector (ethyl thiocyanate) is 150 g / t, and the total amount of frother (MIBC) is 20 g / t. The amount of collector used in the coarse flotation is 70% of the total amount, and the amount of frother used is 80% of the total amount.

[0123] ③ Regrinding of rough concentrate: regrinding to a particle size of -0.037mm accounting for 85%, and a pulp concentration of 28%;

[0124] ④ Blank Refinement: Three blank refinements yield a copper-sulfur mixed concentrate;

[0125] ⑤ Low-alkali copper-sulfur separation: 1 roughing, 3 cleaning, 1 scavenging. In the roughing process, 200 g / t of flotation inhibitor is added, pH=9; in the cleaning process, 80 g / t of flotation inhibitor is added, pH=8.5, and the stirring time of the slurry in a single cleaning process is 3 min; in the separation scavenging process, the amount of collector (ethyl thiocyanate) added is 3 g / t, and the stirring time of the slurry is 3 min.

[0126] Example 2

[0127] This embodiment provides a flotation depressant for recovering copper from magnetically separated iron tailings and a specific flotation process, which differs from Embodiment 1 only in that:

[0128] Inhibitor ratio (parts by weight): 14 parts sulfonated modified tannin (MDH25429), 7 parts sodium cyanurate, 1.5 parts carboxymethyl chitosan (degree of deacetylation of 90%, viscosity of 100 mP·s), and 8 parts sodium carbonate.

[0129] Flotation feedstock: magnetic separation iron tailings, with a mass percentage content of 0.036% Cu and 0.35% S.

[0130] Low-alkali copper-sulfur separation: 1 roughing, 3 cleaning, 1 scavenging. In the roughing stage, 150 g / t of flotation inhibitor is added, pH=8.5; in the cleaning stage, 80 g / t of flotation inhibitor is added, pH=8.5.

[0131] Example 3

[0132] The only difference from Example 1 is that the sulfonated modified tannin SMK in the flotation inhibitor is 10 parts by weight.

[0133] Example 4

[0134] The only difference from Example 1 is that the sulfonated modified tannin SMK in the flotation inhibitor is 25 parts by weight.

[0135] Example 5

[0136] The only difference from Example 1 is that the sodium cyanate in the flotation inhibitor is 4 parts by weight.

[0137] Example 6

[0138] The only difference from Example 1 is that the sodium cyanate content in the flotation inhibitor is 14 parts by weight.

[0139] Example 7

[0140] The only difference from Example 1 is that the weight of carboxymethyl chitosan in the flotation inhibitor is 0.5 parts.

[0141] Example 8

[0142] The only difference from Example 1 is that the weight of carboxymethyl chitosan in the flotation inhibitor is 5 parts.

[0143] Example 9

[0144] The only difference from Example 1 is that the carbonate content in the flotation inhibitor is 5 parts by weight.

[0145] Example 10

[0146] The only difference from Example 1 is that the carbonate content in the flotation inhibitor is 15 parts by weight.

[0147] Example 11

[0148] The only difference from Example 1 is that the degree of deacetylation of carboxymethyl chitosan in the flotation inhibitor is 70%.

[0149] Example 12

[0150] The only difference from Example 1 is that the degree of deacetylation of carboxymethyl chitosan in the flotation inhibitor is 95%.

[0151] Example 13

[0152] The only difference from Example 1 is that the viscosity of carboxymethyl chitosan in the flotation inhibitor is 30 mP·s.

[0153] Example 14

[0154] The only difference from Example 1 is that the viscosity of carboxymethyl chitosan in the flotation inhibitor is 150 mP·s.

[0155] Comparative Example 1

[0156] This example uses the traditional lime process, with lime as the inhibitor at a dosage of 2000g / t, pH=12.0, and the rest is the same as in Example 1.

[0157] Comparative Example 2

[0158] The only difference from Example 1 is that the flotation inhibitor is replaced with an equal amount of sulfonated tannin.

[0159] Comparative Example 3

[0160] The only difference from Example 1 is that the flotation inhibitor is replaced with an equal amount of carboxymethyl chitosan.

[0161] Comparative Example 4

[0162] The only difference from Example 1 is that the sulfonated tannin in the flotation inhibitor is replaced with an equal amount of tannin.

[0163] Comparative Example 5

[0164] The only difference from Example 1 is that the sulfonated tannin in the flotation inhibitor is replaced with an equal amount of catechol.

[0165] Comparative Example 6

[0166] The only difference from Example 1 is that the sodium cyanurate in the flotation inhibitor is replaced with an equal amount of sodium cyanurate carbide.

[0167] Comparative Example 7

[0168] The only difference from Example 1 is that the carboxymethyl chitosan in the flotation inhibitor is replaced with an equal amount of thiomethyl chitosan.

[0169] Comparative Example 8

[0170] The only difference from Example 1 is that the carboxymethyl chitosan in the flotation inhibitor is replaced with an equal amount of chitosan.

[0171] The flotation results of the above embodiments and comparative examples are shown in Table 1 below.

[0172] Table 1

[0173]

[0174] As shown in Table 1, the solution provided by this invention achieves highly efficient selective inhibition of pyrite at a slurry pH of 8-9 through the synergistic effect between the components, while having no significant inhibitory effect on chalcopyrite. It is suitable for low-grade, fine-grained, magnetically separated iron tailings and can obtain copper concentrate with a Cu grade ≥19.22% and a recovery rate ≥72.50%. Under the preferred scheme, copper concentrate with a Cu grade ≥20.08% and a recovery rate ≥74.59% can be obtained. This solves the problems of foam stickiness, equipment scaling, and difficulty in meeting the standards for high-alkali tailings in traditional lime high-alkali processes. It has the advantages of low alkali, high efficiency, and environmental protection, and has broad prospects for industrial application.

[0175] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0176] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0177] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A flotation depressant for recovering copper from magnetically separated iron tailings, characterized in that, The flotation inhibitors include: Sulfonated modified tannin, sodium cyanurate, carboxymethyl chitosan and carbonate.

2. The flotation depressant as described in claim 1, characterized in that, The flotation inhibitor comprises, by weight, the following: Sulfonated modified tannin 12-20 parts, sodium cyanurate 6-12 parts, carboxymethyl chitosan 1-3 parts and carbonate 6-12 parts.

3. The flotation depressant as described in claim 1, characterized in that, The degree of deacetylation of the carboxymethyl chitosan is 80-90%.

4. The flotation depressant as described in claim 1, characterized in that, The viscosity of the carboxymethyl chitosan is 50-100 mP·s.

5. The flotation depressant as described in claim 1, characterized in that, The carbonate includes one or a combination of at least two of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate.

6. A flotation method for recovering copper from magnetically separated iron tailings, characterized in that, The flotation method includes: The tailings slurry was subjected to a first roughing process and a copper scavenging process to obtain copper-sulfur crude concentrate and tailings. The copper-sulfur crude concentrate is regrinded and then subjected to a first cleaning process to obtain a copper-sulfur mixed concentrate. Copper-sulfur mixed concentrate is subjected to a second roughing and a second cleaning process to obtain copper concentrate; The tailings from the second roughing process were separated and scavenged to obtain sulfur concentrate; The second coarse flotation and the second fine flotation contain flotation inhibitors as described in any one of claims 1-5.

7. The flotation method as described in claim 6, characterized in that, The -0.074mm particle size accounts for 55-65% of the total particle mass in the tailings slurry. Preferably, the mass concentration of the tailings slurry is 32-38%.

8. The flotation method as described in claim 6, characterized in that, The flotation reagents used in the first roughing and copper scavenging processes include: a collector with a total dosage of 80-160 g / t and a frother with a total dosage of 10-30 g / t; Preferably, the amount of collector used in the first roughing process is 68-72% of the total amount, and the amount of foaming agent is 78-82% of the total amount; Preferably, the first coarse selection is performed at least once; Preferably, the first roughing process is performed ≥2 times, and the middlings obtained from the first roughing process are sequentially returned to the previous operation; Preferably, the copper sweeping is performed at least twice; Preferably, the middlings obtained from the copper scavenging are sequentially returned to the previous operation.

9. The flotation method as described in claim 6, characterized in that, The regrinding includes: regrinding the rough concentrate until the mass percentage of -0.037mm particles is ≥85% of all particles; Preferably, the mass concentration of the slurry obtained from the regrinding is 26-30%; Preferably, the first selection method includes: blank selection; Preferably, the first selection is performed at least three times; Preferably, the refined ore obtained from the first selection is sequentially returned to the previous operation.

10. The flotation method as described in claim 6, characterized in that, In the second coarse selection, the pH value of the slurry is controlled to be 8-9; Preferably, the amount of flotation inhibitor used in the second roughing stage is 100-500 g / t; Preferably, the pH value of the slurry is controlled to be 8-9 in the second refining process; Preferably, the amount of flotation inhibitor used in the second selection process is 20-100 g / t; Preferably, the second selection is performed at least three times; Preferably, the refined ore obtained from the second refining process is sequentially returned to the previous operation; Preferably, the stirring time of the slurry in a single second refining process is controlled to be 2-4 minutes; Preferably, a collector is added during the separation and scanning process, and the amount added is 1-5 g / t; Preferably, the separation and scanning are performed at least once; Preferably, the stirring time of the slurry in a single separation and sweep is controlled to be 2-4 minutes; Preferably, the separation and scavenging are performed ≥2 times, and the middlings obtained from the separation and scavenging are sequentially returned to the previous operation.

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