Pyrite combined inhibitor and application thereof

Abstract

The invention discloses a pyrite combined inhibitor and application thereof, and belongs to the technical field of mineral flotation. The combined inhibitor is composed of ascorbic acid and ferrous sulfate. The combined inhibitor is used for flotation separation of chalcopyrite and pyrite, and specifically comprises the steps that raw ore is crushed and ground to achieve monomer dissociation between minerals, then pulp mixing is conducted, and ore pulp to be floated is obtained; and a combined inhibitor ascorbic acid and ferrous sulfate, a collecting agent and a foaming agent are added into the ore pulp for flotation operation, and copper concentrate and tailings are obtained. The combined inhibitor has a strong inhibition effect on pyrite and can effectively realize flotation separation of chalcopyrite and pyrite, the addition of ferrous sulfate can strengthen inhibition of ascorbic acid on pyrite and reduce the dosage of ascorbic acid, and the beneficiation cost is reduced while the separation effect of copper-sulfur sulfide ore is improved.

Description

Technical Field

[0001] This invention relates to the field of mineral flotation technology, specifically to a pyrite composite inhibitor and its application. Background Technology

[0002] Chalcopyrite and pyrite, as important sources of copper and sulfur, are often found together in copper sulfide deposits. However, with the increase in utilization years, copper sulfide deposits face problems such as low grade and complex intergrowth relationships, which makes copper-sulfur separation difficult and further exacerbates the problem of copper-sulfur concentrate co-containment.

[0003] Many scholars have explored feasible ways to replace high-alkali processes with single or combined inhibitors in low-alkalinity or even lime-free systems. For example, patent application number CN201711082077.8 describes using 1500-2500 g / t NaOH and 3000-5000 g / t lime as inhibitors and pH adjusters, respectively, to pre-adjust the slurry to 11-12 during grinding. Then, using the highly efficient inhibitor XKY-03 (a composition of sodium humate, potassium permanganate, and sodium mercaptoacetate) and the synthetic collector XKP-03 as collectors, copper and sulfur are separated through a four-stage copper-sulfur mixed roughing process and regrinding of the concentrate, followed by a "roughing, scavenging, and cleaning" flotation operation. Patent application number CN202110550310.0 proposes using an inhibitor composed of sodium percarbonate and humate in a specific ratio to achieve flotation separation of secondary copper sulfide and pyrite under low-alkalinity conditions with low lime usage. Patent application CN201610307695.7 proposes using lime as a single depressant and butyl xanthate as a collector for copper-sulfur separation in tailings after weak magnetic separation to remove pyrrhotite. When using lime in flotation operations, lime always has a certain inhibitory effect on pyrite. On the one hand, the advantages of novel combined depressants cannot be fully realized; on the other hand, in industrial applications, the long-term accumulation of lime during the beneficiation process can cause foam stickiness, pipe scaling, equipment corrosion, and even environmental problems. Furthermore, there are issues with cost and stable operation in industrial production. Therefore, exploring a pyrite depressant that combines high selectivity, environmental friendliness, low cost, and good stability in the copper-sulfur separation process is of significant importance for improving copper-sulfur separation indicators, increasing the utilization rate of copper and sulfur resources, enhancing the economic benefits of beneficiation plants, and constructing green mines. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, the present invention aims to provide a pyrite composite inhibitor, wherein the composite inhibitor is ascorbic acid and ferrous sulfate, wherein the mass ratio of ascorbic acid to ferrous sulfate is (4-5):1; the structural formula of the ascorbic acid is as follows: ; This combination of inhibitors exhibits good selective inhibition of sulfur in preferential flotation and can reduce the amount of inhibitor required.

[0005] Another objective of this invention is to provide an application of pyrite-based combined depressants in copper-sulfur flotation separation, specifically including the following steps: (1) After crushing and grinding the raw ore, the slurry is prepared to obtain the slurry to be floated.

[0006] (2) Add a combination of inhibitors, collectors and frothers to the slurry to be floated in sequence to carry out flotation operations and obtain copper concentrate and tailings.

[0007] Preferably, in step (1) of the present invention, 80-85% of the particles are ground to a fineness of -0.074 mm.

[0008] Preferably, the concentration of the pulp to be flotated in step (1) of the present invention is 30%-35%.

[0009] Preferably, the flotation operation in step (2) of the present invention includes one roughing, two sweeping and two cleaning.

[0010] Preferably, in step (2) of the present invention, the collector is ethyl xanthate and butyl xanthate, and the foaming agent is 2 # Oil.

[0011] Preferably, the dosage of the crude selection combination inhibitor in this invention is 1800-2200 g / t, the dosage of ethyl xanthate is 25-30 g / t, and the dosage of butyl xanthate is 20-25 g / t. # The oil usage is 20-25g / t.

[0012] Preferably, in the selective processing described in this invention, the dosage of the combined inhibitor in Selective Process I is 900-1100 g / t; and the dosage of the combined inhibitor in Selective Process II is 450-550 g / t.

[0013] Preferably, in the scavenging process described in this invention, the amount of ethyl xanthate used in scavenging operation I is 15-20 g / t, and the amount of butyl xanthate used is 10-15 g / t. # The oil dosage is 10-15 g / t; in the scavenging II operation, the dosage of ethyl xanthate is 10-15 g / t, and the dosage of butyl xanthate is 5-10 g / t. # The oil usage is 5-10g / t.

[0014] This invention provides a pyrite composite inhibitor and its application, which has the following beneficial effects: (1) The combined inhibitor of the present invention is composed of ascorbic acid and ferrous sulfate. The combined inhibitor has a selective inhibitory effect on pyrite and a weak affinity for chalcopyrite. While selectively inhibiting pyrite, it minimizes the impact of the combined inhibitor on the floatability of chalcopyrite, thereby achieving efficient separation of chalcopyrite and pyrite, reducing the pyrite content in copper concentrate, effectively improving the copper grade in copper concentrate, further improving the efficiency of the beneficiation plant and reducing the difficulty of subsequent metallurgical flue gas treatment.

[0015] (2) While achieving the technical objectives, the present invention has good economic efficiency. Through the synergistic effect of ascorbic acid and ferrous sulfate, the dosage of the drug can be reduced while achieving the same inhibitory effect, thereby reducing the overall drug cost. Attached Figure Description

[0016] Figure 1 This is a flotation process flow diagram of Embodiments 1-3 of the present invention.

[0017] Figure 2 This is a flotation process flow diagram of comparative examples 1-6 of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the embodiments and comparative examples of this invention, the raw ore for flotation was taken from primary copper-sulfur ore from the Dapingzhang copper mine area in Simao, Pu'er, Yunnan Province. The copper content was about 0.44-0.53%, and the sulfur content was about 10-11%. The copper and sulfur-containing minerals were mainly chalcopyrite and pyrite, and the gangue minerals were mainly quartz and a small amount of aluminosilicates.

[0020] Example 1 In this embodiment, the combined inhibitors include ascorbic acid and ferrous sulfate, wherein the mass ratio of ascorbic acid to ferrous sulfate is 4:1, the collectors are ethyl xanthate and butyl xanthate, and the foaming agent is 2. # The oil is used for flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 1 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 80% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 30%.

[0021] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the combined inhibitors ascorbic acid and ferrous sulfate (total dosage of ascorbic acid and ferrous sulfate is 1800 g / t), collectors ethyl xanthate (dosage is 25 g / t) and butyl xanthate (dosage is 20 g / t), and frother 2 to the slurry to be flotated. # The oil (at a rate of 20g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0022] ② Add a combination of inhibitors, ascorbic acid and ferrous sulfate (total amount of ascorbic acid and ferrous sulfate is 900 g / t), to the rough concentrate for cleaning operation I. Then add a combination of inhibitors, ascorbic acid and ferrous sulfate (total amount of ascorbic acid and ferrous sulfate is 450 g / t), to the concentrate produced by cleaning operation I for cleaning operation II to obtain the final copper concentrate. The middlings from cleaning operations I and II are returned to the rougher and cleaning operation I respectively to form a closed loop.

[0023] ③ Add collectors ethyl xanthate (15 g / t) and butyl xanthate (10 g / t) to the roughing tailings, along with frother 2. # Oil (10 g / t) is used for scavenging operation I; then, collectors ethyl xanthate (10 g / t) and butyl xanthate (5 g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (5g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0024] Comparative Example 1 In this comparative example, a single depressant, lime, was used for the flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 2 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 80% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 30%.

[0025] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the following to the flotation slurry: lime (3000 g / t), ethyl xanthate (25 g / t), butyl xanthate (20 g / t), and frother 2 g / t. # The oil (at a rate of 20g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0026] ② Add lime inhibitor (1500g / t) to the roughing concentrate for cleaning operation I. Then add lime inhibitor (750g / t) to the concentrate produced by cleaning operation I for cleaning operation II to obtain the final copper concentrate. The middlings from cleaning operations I and II are returned to roughing and cleaning operation I in sequence to form a closed loop.

[0027] ③ Add collectors ethyl xanthate (15 g / t) and butyl xanthate (10 g / t) to the roughing tailings, along with frother 2. # Oil (10 g / t) is used for scavenging operation I; then, collectors ethyl xanthate (10 g / t) and butyl xanthate (5 g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (5g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0028] Comparative Example 2 In this comparative example, ascorbic acid, a single inhibitor, was used for the flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 2 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 80% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 30%.

[0029] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the inhibitor ascorbic acid (1800 g / t), collectors ethyl xanthate (25 g / t) and butyl xanthate (20 g / t), and frother 2 to the slurry to be flotated. # The oil (at a rate of 20g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0030] ② Add ascorbic acid inhibitor (900g / t) to the rough concentrate for fine selection I operation, and then add ascorbic acid inhibitor (450g / t) to the concentrate produced by fine selection I operation for fine selection II operation to obtain the final copper concentrate. The middlings from fine selection I and II are returned to roughing and fine selection I in sequence to form a closed loop.

[0031] ③ Add collectors ethyl xanthate (15 g / t) and butyl xanthate (10 g / t) to the roughing tailings, along with frother 2. # Oil (10 g / t) is used for scavenging operation I; then, collectors ethyl xanthate (10 g / t) and butyl xanthate (5 g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (5g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0032] Example 2 In this embodiment, the combined inhibitors include ascorbic acid and ferrous sulfate, wherein the mass ratio of ascorbic acid to ferrous sulfate is 5:1. The collectors include ethyl xanthate and butyl xanthate, and the foaming agent is 2. # The oil is used for flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 1 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 85% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 35%.

[0033] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the combined inhibitors ascorbic acid and ferrous sulfate (total dosage of ascorbic acid and ferrous sulfate is 2200 g / t), collectors ethyl xanthate (dosage is 30 g / t) and butyl xanthate (dosage is 25 g / t), and frother 2 to the ore pulp to be flotated. # The oil (at a rate of 25g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0034] ② Add a combination of inhibitors, ascorbic acid and ferrous sulfate (total amount of ascorbic acid and ferrous sulfate is 1100g / t), to the rough concentrate for cleaning operation I. Then add a combination of inhibitors, ascorbic acid and ferrous sulfate (total amount of ascorbic acid and ferrous sulfate is 550g / t), to the concentrate produced by cleaning operation I for cleaning operation II to obtain the final copper concentrate. The middlings from cleaning operations I and II are returned to the rougher and cleaning operation I respectively to form a closed loop.

[0035] ③ Add collectors ethyl xanthate (20 g / t) and butyl xanthate (15 g / t) and frother 2 to the roughing tailings. # Oil (15g / t) is used for scavenging operation I; then, collectors ethyl xanthate (15g / t) and butyl xanthate (5g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (5g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0036] Comparative Example 3 In this comparative example, a single depressant, lime, was used for the flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 2 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 85% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 35%.

[0037] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the following to the flotation slurry: lime (4000 g / t), ethyl xanthate (30 g / t), butyl xanthate (25 g / t), and frother 2. # The oil (at a rate of 25g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0038] ② Add lime inhibitor (2000g / t) to the rougher concentrate for cleaning operation I. Then add lime inhibitor (1000g / t) to the concentrate produced by cleaning operation I for cleaning operation II to obtain the final copper concentrate. The middlings from cleaning operations I and II are returned to rougher and cleaning operation I respectively to form a closed loop.

[0039] ③ Add collectors ethyl xanthate (20 g / t) and butyl xanthate (15 g / t) and frother 2 to the roughing tailings. # Oil (15g / t) is used for scavenging operation I; then, collectors ethyl xanthate (15g / t) and butyl xanthate (5g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (5g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0040] Comparative Example 4 In this comparative example, ascorbic acid, a single inhibitor, was used for the flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 2 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 85% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 35%.

[0041] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the inhibitor ascorbic acid (2200 g / t), collectors ethyl xanthate (30 g / t) and butyl xanthate (25 g / t), and frother 2 to the slurry to be flotated. # The oil (at a rate of 25g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0042] ② Add ascorbic acid inhibitor (1100g / t) to the rough concentrate for fine selection I operation, and then add ascorbic acid inhibitor (550g / t) to the concentrate produced by fine selection I for fine selection II operation to obtain the final copper concentrate. The middlings from fine selection I and II are returned to roughing and fine selection I in sequence to form a closed loop.

[0043] ③ Add collectors ethyl xanthate (20 g / t) and butyl xanthate (15 g / t) and frother 2 to the roughing tailings. # Oil (15g / t) is used for scavenging operation I; then, collectors ethyl xanthate (15g / t) and butyl xanthate (5g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (5g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0044] Example 3 In this embodiment, the combined inhibitors include ascorbic acid and ferrous sulfate, wherein the mass ratio of ascorbic acid to ferrous sulfate is 4.5:1. The collectors include ethyl xanthate and butyl xanthate, and the foaming agent is 2... # The oil is used for flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 1 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 83% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 33%.

[0045] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the combined inhibitors ascorbic acid and ferrous sulfate (total dosage of ascorbic acid and ferrous sulfate is 2000 g / t), collectors ethyl xanthate (dosage is 28 g / t) and butyl xanthate (dosage is 22 g / t), and frother 2 to the slurry to be flotated. # The oil (at a rate of 22g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0046] ② Add a combination of inhibitors, ascorbic acid and ferrous sulfate (total amount of ascorbic acid and ferrous sulfate is 1000g / t), to the rough concentrate for cleaning operation I. Then add a combination of inhibitors, ascorbic acid and ferrous sulfate (total amount of ascorbic acid and ferrous sulfate is 500g / t), to the concentrate produced by cleaning operation I for cleaning operation II to obtain the final copper concentrate. The middlings from cleaning operations I and II are returned to the rougher and cleaning operation I respectively to form a closed loop.

[0047] ③ Add collectors ethyl xanthate (18 g / t) and butyl xanthate (12 g / t) to the roughing tailings, along with frother 2. # Oil (12 g / t) is used for scavenging operation I; then, collectors ethyl xanthate (12 g / t) and butyl xanthate (8 g / t), and frother 2 are added to the tailings from scavenging operation I. #Oil (8g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0048] Comparative Example 5 In this comparative example, a single depressant, lime, was used for the flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 2 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 83% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 33%.

[0049] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the following to the flotation slurry: lime (3500 g / t), ethyl xanthate (28 g / t), butyl xanthate (22 g / t), and frother 2 g / t. # The oil (at a rate of 22g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0050] ② Add lime inhibitor (1750 g / t) to the rougher concentrate for cleaning operation I, and then add lime inhibitor (875 g / t) to the concentrate produced by cleaning operation I for cleaning operation II to obtain the final copper concentrate. The middlings from cleaning operations I and II are returned to rougher and cleaning operation I respectively to form a closed loop.

[0051] ③ Add collectors ethyl xanthate (18 g / t) and butyl xanthate (12 g / t) to the roughing tailings, along with frother 2. # Oil (12 g / t) is used for scavenging operation I; then, collectors ethyl xanthate (12 g / t) and butyl xanthate (8 g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (8g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0052] Comparative Example 6 In this comparative example, ascorbic acid, a single inhibitor, was used for the flotation separation of chalcopyrite and pyrite. The flotation process is as follows: Figure 2 As shown, the specific steps are as follows: (1) The raw ore is crushed and ground to 83% of the size of -0.074mm, and then the slurry is adjusted to obtain the slurry to be floated. The concentration of the slurry for flotation is 33%.

[0053] (2) Perform flotation operation on the slurry to be flotated, specifically as follows: ① Add the inhibitor ascorbic acid (2000 g / t), collectors ethyl xanthate (28 g / t) and butyl xanthate (22 g / t), and frother 2 to the slurry to be flotated. # The oil (at a rate of 22g / t) is used for roughing operations to obtain roughing concentrate and roughing tailings.

[0054] ② Add ascorbic acid inhibitor (1000g / t) to the rough concentrate for fine selection I operation, and then add ascorbic acid inhibitor (500g / t) to the concentrate produced by fine selection I operation for fine selection II operation to obtain the final copper concentrate. The middlings from fine selection I and II are returned to roughing and fine selection I in sequence to form a closed loop.

[0055] ③ Add collectors ethyl xanthate (18 g / t) and butyl xanthate (12 g / t) to the roughing tailings, along with frother 2. # Oil (12 g / t) is used for scavenging operation I; then, collectors ethyl xanthate (12 g / t) and butyl xanthate (8 g / t), and frother 2 are added to the tailings from scavenging operation I. # Oil (8g / t) is subjected to scavenging operation II to obtain scavenging II concentrate and final tailings. The scavenging I and II concentrates are returned sequentially to roughing and scavenging I, respectively, forming a closed loop.

[0056] The flotation results of Examples 1-3 and Comparative Examples 1-6 are shown in Table 1 below.

[0057] Table 1 Note: Copper enrichment ratio (%) = concentrate grade / raw ore grade.

[0058] As shown in Table 1, by comparing the experimental results of Comparative Example 2 with Example 1, Comparative Example 4 with Example 2, and Comparative Example 6 with Example 3, it can be seen that the grade and recovery rate of sulfur in the copper concentrate of the examples are significantly lower than those of the comparative examples, indicating that the synergistic effect of ferrous sulfate and ascorbic acid can enhance the inhibitory effect on pyrite; in addition, the grade of copper concentrate in the examples is at least 3.68 percentage points higher than that of the comparative examples, indicating that the combined inhibitor can not only effectively reduce the sulfur content in copper concentrate, but also improve the quality of copper concentrate.

[0059] By comparing the experimental results of Comparative Examples 1, 3, and 5 with those of Examples 1-3, it can be seen that the sulfur grade of the copper concentrate in the examples is no higher than 27%, while the grade in the comparative examples is higher than 33%. Moreover, the sulfur grade in the copper concentrate is reduced by at least 8.76 percentage points compared with the comparative examples. At the same time, the sulfur recovery rate in the copper concentrate of the examples is reduced by up to 3.12 percentage points compared with the use of lime, indicating that the combined inhibitor has a stronger inhibitory effect on sulfur than lime. Furthermore, the copper concentrate grade of the examples is increased by at least 2.71 percentage points compared with the comparative examples.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pyrite composite inhibitor, characterized in that, The combined inhibitor is ascorbic acid and ferrous sulfate, wherein the mass ratio of ascorbic acid to ferrous sulfate is (4-5):1; the structural formula of ascorbic acid is as follows: .

2. The application of the pyrite composite inhibitor as described in claim 1 in copper-sulfur flotation separation, characterized in that, Specifically, the following steps are included: (1) After crushing and grinding the raw ore, the pulp is prepared to obtain the slurry to be floated; (2) Add a combination of inhibitors, collectors and frothers to the slurry to be floated in sequence to carry out flotation operations and obtain copper concentrate and tailings.

3. The application of the pyrite combined depressant according to claim 2 in copper-sulfur flotation separation, characterized in that, In step (1), grinding to a particle fineness of -0.074 mm accounts for 80-85%.

4. The application of the pyrite combined depressant according to claim 2 in copper-sulfur flotation separation, characterized in that, The concentration of the pulp to be floated in step (1) is 30%-35%.

5. The application of the pyrite combined depressant according to claim 2 in copper-sulfur flotation separation, characterized in that, The flotation operation described in step (2) includes one roughing, two scavenging and two cleaning processes.

6. The application of the pyrite combined depressant according to claim 2 in copper-sulfur flotation separation, characterized in that, The collector in step (2) is ethyl xanthate and butyl xanthate, and the foaming agent is 2 # Oil.

7. The application of the pyrite combined depressant according to claim 5 in copper-sulfur flotation separation, characterized in that, The dosage of the crude selected combination inhibitor is 1800-2200 g / t, the dosage of ethyl xanthate is 25-30 g / t, and the dosage of butyl xanthate is 20-25 g / t. # The oil usage is 20-25g / t.

8. The application of the pyrite combined depressant according to claim 5 in copper-sulfur flotation separation, characterized in that, In the aforementioned selection process, the dosage of the combined inhibitor in the selection process I is 900-1100 g / t; and the dosage of the combined inhibitor in the selection process II is 450-550 g / t.

9. The application of the pyrite combined depressant according to claim 5 in copper-sulfur flotation separation, characterized in that, In the aforementioned scavenging process, the dosage of ethyl xanthate in scavenging operation I is 15-20 g / t, and the dosage of butyl xanthate is 10-15 g / t. # The oil usage is 10-15g / t; In the scavenging operation II, the dosage of ethyl xanthate is 10-15 g / t, and the dosage of butyl xanthate is 5-10 g / t. # The oil usage is 5-10g / t.

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