A method for separating sphalerite and pyrrhotite by cascade flotation process

Abstract

The present invention relates to a method for separating sphalerite and pyrrhotite by a cascade flotation process, and belongs to the field of mineral processing. The method aims at the problems that the X fluctuation in the pyrrhotite molecular formula causes the floatability of different types of pyrrhotite to fluctuate greatly, resulting in the difficulty of separating sphalerite from pyrrhotite, the low quality of zinc concentrate, and the large amount of copper sulfate. The present invention mixes and stirs the sphalerite and pyrrhotite slurry, and then performs cascade flotation to realize the cascade activation of pyrrhotite with different floatation activities, and then performs zinc-sulfur activation and zinc-sulfur separation in the third-stage flotation tailings to produce zinc concentrate and zinc tailings. The present invention greatly reduces the difficulty of separating sphalerite from pyrrhotite by the cascade flotation process, and the zinc concentrate produced contains Zn>49%. At the same time, the amount of copper sulfate consumed by zinc-sulfur separation is reduced by 95% compared with the traditional separation process, which greatly reduces the separation cost of sphalerite and pyrrhotite.

Description

Technical Field

[0001] The present invention relates to the field of mineral processing, and particularly relates to a method for separating marmatite and pyrrhotite by a cascade flotation process, which is particularly suitable for separating the mixed materials of marmatite and pyrrhotite with the pyrrhotite mineral content accounting for 35% - 65% of the total mineral content in the material to be treated. Background Art

[0002] Due to the partial substitution of Zn atoms in the sphalerite lattice by Fe in marmatite, the lattice hole density of sphalerite is reduced, resulting in the reduction of the flotability of marmatite compared with sphalerite, and the magnetism increases with the increase of iron atoms. In the deposits where marmatite and pyrrhotite coexist, the flotability of the two minerals is necessarily close and the magnetic difference is small. The chemical formula of pyrrhotite Fe in nature is Fe 3+ S, 0 < X < 0.233. When X approaches 0, the magnetism of pyrrhotite is the highest and the flotability is the best. When X approaches 0.233, the magnetism of pyrrhotite is the weakest and the flotability is significantly reduced, but for Cu in the pulp 1-x S, 0 < X < 0.233. When X approaches 0, the magnetism of pyrrhotite is the highest and the flotability is the best. When X approaches 0.233, the magnetism of pyrrhotite is the weakest and the flotability is significantly reduced, but for Cu in the pulp 2+It has the strongest adsorption capacity. After the adsorption reaction, its floatability is better than that of sphalerite. Therefore, when treating a mixture of pyrrhotite and sphalerite, and the pyrrhotite content accounts for 35% to 65% of the total mineral content, after copper sulfate is added to zinc flotation, the activation order is to activate pyrrhotite first and then sphalerite, resulting in an extremely high actual dosage of copper sulfate (>1000g / t), and the activated pyrrhotite is extremely difficult to be inhibited by inhibitors such as lime and sodium humate, resulting in great difficulty in separating sphalerite from pyrrhotite, low zinc concentrate grade, and the zinc concentrate produced often contains Zn<20%, and the separation index is not ideal. In order to improve the separation efficiency of sphalerite and pyrrhotite in such ores, the deep dissociation-strong inhibitor method is currently used to achieve strong inhibition of pyrrhotite. Patent CN201710631148.9 provides a method of regrinding-deep inhibition of mixed concentrates of sphalerite and pyrrhotite. This method solves the problems of great separation difficulty and low separation accuracy to a certain extent. However, this method requires regrinding of the mixed concentrate, which has high energy consumption. The new inhibitor is an unconventional mineral processing agent and is difficult to be widely promoted. Patent CN202010348276.4 provides a method for treating a mixture of sphalerite and pyrrhotite by a combined magnetic-flotation process. The method treats the zinc coarse tailings by adding magnetic separation to remove some pyrrhotite with higher magnetic properties. The method avoids the interference of a small amount of pyrrhotite with good magnetic properties and good floatability (X tends to 0) on the quality of zinc concentrate to a certain extent. However, the method is only applicable to the case where the X value of the pyrrhotite molecular formula fluctuates slightly and there is only a single pyrrhotite with good magnetic properties and good floatability in the material. When the X value fluctuates greatly and there is some pyrrhotite with weak magnetic properties but easily activated by copper sulfate, the method may not be completely applicable.

[0003] In addition, since the materials containing pyrrhotite and sphalerite are mainly tailings after lead is preferentially flotated from sulfide lead-zinc ores, in the process of lead preferential flotation, in order to achieve the output of qualified lead concentrate, pyrrhotite and sphalerite inhibitors need to be added. In the conventional mineral processing process, the lead tailings are subjected to magnetic separation to remove part of the pyrrhotite with good magnetic properties, and then the pyrrhotite inhibitor and sphalerite activator (copper sulfate) are added. Since the amount of pyrrhotite in most materials containing pyrrhotite and sphalerite is much greater than that of sphalerite, and pyrrhotite also has a significant activation effect on copper sulfate, it will have a certain degree of competitive adsorption with copper sulfate. Therefore, in order to fully activate sphalerite, the actual amount of copper sulfate used is extremely high, even reaching 1000g / t to 2000g / t. The pyrrhotite activated by copper sulfate has excellent floatability, resulting in extremely high cost of the reagent used to inhibit the pyrrhotite activated by copper sulfate.

[0004] Therefore, in order to further improve the resource utilization rate of mines containing pyrrhotite and sphalerite, reduce the difficulty of separating pyrrhotite and sphalerite, improve the separation efficiency of sphalerite and pyrrhotite, and reduce the reagent cost in the separation process of pyrrhotite and sphalerite, a novel separation method based on pyrrhotite Fe 1-x The fluctuation of X value in S leads to the step-wise change of the floating activity of pyrrhotite with different molecular formulas. It is necessary to develop a new separation process of sphalerite and pyrrhotite. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a method for separating sphalerite and pyrrhotite by a cascade flotation process. 1-x The difference in S floating activity is achieved through cascade activation-cascade flotation, which realizes the fast flotation of part of the preferentially activated pyrrhotite, and at the same time lays a good foundation for improving the subsequent separation efficiency and reducing the amount of copper sulfate in zinc flotation, thereby greatly reducing the difficulty of separating sphalerite and pyrrhotite. To achieve this goal, the technical solution of the present invention is as follows:

[0006] A method for separating sphalerite and pyrrhotite by a cascade flotation process comprises the following steps:

[0007] S1. The material containing sphalerite and pyrrhotite is transported to a slurry mixing tank for mixing and slurry mixing. During the slurry mixing process, the slurry mass concentration is adjusted to 40% to 45% by concentration or dilution with clean water. If the concentration of the raw material to be processed is higher than 45%, the material is diluted to 45% by adding a certain mass of clean water. If the concentration of the raw material to be processed is lower than 40%, a certain mass of clarified liquid can be removed by sedimentation and concentration. After the slurry mass concentration is concentrated to 40% to 45%, it is used for the next step of processing;

[0008] S2, adding an alcohol foaming agent to the material to be processed produced in step S1, and conveying it to a flotation machine for aeration flotation, the flotation number is one roughing, and the first-stage flotation foam concentrate and the first-stage flotation tailings are produced;

[0009] S3, adding activator 1 and alcohol frother to the first-stage flotation tailings produced in step S2, and then aerating and flotating, the flotation times are one roughing operation, to obtain second-stage flotation froth concentrate and second-stage flotation tailings;

[0010] S4, adding activator 2, collector 1, and alcohol frother to the second-stage flotation tailings produced in step S3, and then aerating and flotating, the flotation times are one roughing operation, to obtain third-stage flotation froth concentrate and third-stage flotation tailings;

[0011] S5, adding pyrrhotite inhibitor, activator 3, collector 2, and alcohol frother in sequence to the third flotation tailings obtained in step S4, and then aerating flotation, the flotation times are one roughing operation, the roughing operation obtains foam concentrate 1 and bottom tailings, the foam concentrate 1 is then added with pyrrhotite inhibitor for concentrating operation, the final foam concentrate after concentrating 1-2 times is zinc concentrate, the concentrating tailings and the second-level foam concentrate obtained in step S2 are combined and returned to the roughing operation in step S5, the bottom tailings are added with collector 2 for two scavenging operations, the scavenged concentrate 1 obtained in the first scavenging is combined with the concentrating tailings and returned to the roughing operation in step S5, the scavenged concentrate 2 obtained in the second scavenging is combined with the third-level flotation foam concentrate obtained in step S4 and returned to the first scavenging operation, forming a complete closed-loop cycle operation, and the bottom tailings of the second scavenging are the final tailings;

[0012] Preferably, the iron-containing sphalerite and pyrrhotite material in step S1 is 85% to 90% of the iron-containing sphalerite and pyrrhotite raw ore that has been crushed and ground to 74 μm.

[0013] Preferably, the first-stage flotation froth concentrate in step S1 contains Zn < 0.1% and S > 37%, and can be directly used as a sulfur concentrate product.

[0014] Preferably, the mass percentage of zinc in the sphalerite and pyrrhotite material containing iron in step S1 is 1.6% to 3.45%, the main sulfide mineral component type in the sphalerite and pyrrhotite material containing iron is pyrrhotite, followed by sphalerite, the pyrrhotite mineral content accounts for 50% to 59.28% of the total mineral content in the material to be processed, and the sphalerite content accounts for 2.43% to 5.30% of the total mineral content in the material to be processed. Conventional mineral processing technology is difficult to separate such sphalerite and pyrrhotite materials, and the separation efficiency is low.

[0015] Preferably, in step S2, the alcohol foaming agent is one of ethanol ether or methyl isobutyl carbinol, and the amount is 5g / t to 10g / t. The direct aeration flotation is used to achieve rapid floating of part of the pyrrhotite with excellent floatability (the X value infinitely tends to 0). Since no foaming agent or collector of sphalerite is added, in step S2, the first-level foam concentrate produced by floating contains Zn<0.1% and Fe>59%, which meets the sales requirements of the iron concentrate.

[0016] Preferably, the alcohol foaming agent added in step S3 is one of ethanol ether or methyl isobutyl carbinol, and the amount is 20 g / t to 30 g / t, and the activator 1 added is one of oxalic acid or citric acid, and the amount is 100 g / t to 150 g / t;

[0017] Preferably, in step S3, by using the activator 1, the surface of part of the pyrrhotite with good floatability (X value is between 0 and 0.08) can be fully activated, and the floatability of the activated pyrrhotite is close to the first-level foam concentrate floated in step S1, and the floating of this part of the pyrrhotite can be achieved by adding a frother;

[0018] Preferably, the second-stage flotation foam concentrate produced in step S3 contains Fe>55%, and its Zn content fluctuates within a certain range depending on the Zn content of the processed material. When the raw material contains Zn>3%, the produced second-stage flotation foam concentrate contains Zn>0.5%, and when the raw mineral material contains Zn<3%, the produced second-stage flotation foam concentrate contains Zn<0.5%, which can be directly combined with the first-stage flotation foam concentrate in step S2; when the second-stage flotation foam concentrate produced in step S3 contains Zn>0.5%, the second-stage flotation foam concentrate is combined with the selected tailings, and the third-stage flotation foam concentrate produced in step S4 is combined with the scavenged concentrate produced in step S5, so as to form a complete flotation closed-circuit process, and realize the complete separation of sphalerite and pyrrhotite;

[0019] Preferably, the alcohol foaming agent added in step S4 is one of ethanol ether or methyl isobutyl carbinol, and the amount is 40 g / t to 50 g / t. The collector 1 added in step S4 is ethyl sodium xanthate, and the amount is 10 g / t to 20 g / t. The activator 2 added in step S4 is FeSO 4 , dosage is 100g / t~200g / t;

[0020] Preferably, in step S4, the surface of pyrrhotite (X value is between 0.08 and 0.200) with weak floatability can be fully activated by activator 2, and the floatability of the activated pyrrhotite is close to that of the second-stage foam concentrate floated in step S2. The floating of this part of pyrrhotite can be achieved by adding a small amount of ethyl sodium xanthate with good selectivity and a foaming agent.

[0021] Preferably, the alcohol foaming agent added in step S5 is one of ethanol ether or methyl isobutyl carbinol, and the amount is 10g / t to 15g / t. The activator 3 in step S5 is copper sulfate, and the amount is 80g / t to 120g / t. The pyrrhotite inhibitor in step S5 is lime, and the amount of rough selection is 250g / t to 300g / t, and the amount of fine selection is 150g / t. The collector 2 in step S5 is one of butyl sodium xanthate or amyl potassium xanthate, and the amount of rough selection is 60g / t to 80g / t, and the amount of scavenging selection is 10g / t to 20g / t.

[0022] Preferably, the activator 3 added in step S5 is copper sulfate. Since most of the pyrrhotite with good floatability is removed by step flotation through steps S2, S3, and S4, the residual pyrrhotite in the third-stage flotation tailings has poor floatability and low content, so the amount of copper sulfate required for competitive adsorption with marmatite is greatly reduced. Under the condition that the amount of copper sulfate is 80g / t to 120g / t, the marmatite in the third-stage flotation tailings can be fully activated, and the activated marmatite can be fully floated using conventional butyl sodium xanthate or amyl sodium xanthate. In step S5, since the content of the residual pyrrhotite is low, by adding part of the pyrrhotite inhibitor, the pyrrhotite can be fully inhibited, and the zinc concentrate obtained after concentration contains Zn>49%.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Compared with the conventional method of separating sphalerite and pyrrhotite by heavy pressing and heavy pulling, the present invention makes full use of the pyrrhotite Fe 1-x The fluctuation of the X value in S leads to a large fluctuation in the floatability of pyrrhotite. In the process of steps S2, S3 and S4, the pyrrhotite with excellent floatability is naturally floated without adding an activator, oxalic acid and citric acid are added to activate part of the pyrrhotite with good floatability, and ferrous sulfate is added to activate the pyrrhotite with poor floatability. Then, the pyrrhotite is pre-removed, and the difficulty of separating sphalerite and pyrrhotite is greatly reduced.

[0025] (2) By pre-removing pyrrhotite with different floating activities through the step flotation of steps S2, S3, and S4, the amount of pyrrhotite in the slurry when copper sulfate and sphalerite are activated can be greatly reduced. The amount of copper sulfate used in zinc roughing is reduced by 95% compared with the amount of copper sulfate used in the conventional separation process, which not only saves the cost of reagents, but also reduces the pollution risk of residual heavy metal ions in the ore dressing wastewater;

[0026] (3) Since the amount of pyrrhotite minerals that are easily activated repeatedly by copper sulfate is greatly reduced, the amount of pyrrhotite minerals that float up during zinc flotation will also be significantly reduced, so the difficulty of obtaining zinc concentrate containing Zn>49% by flotation is greatly reduced, which is beneficial to flotation operation;

[0027] (4) In steps S2 and S3, an iron concentrate product mainly composed of magnetite that meets sales standards can be directly produced. However, conventional processes all use zinc concentrate mainly composed of sphalerite produced by preferential flotation. In this process, a large amount of inhibitors are added to control the floatability of pyrrhotite, and the pyrrhotite is pressed into the zinc tailings. If the pyrrhotite resources in the zinc tailings are to be recovered, sulfuric acid needs to be added as an activator for the suppressed pyrrhotite. The recovery process is long and the reagent cost is high. The method for recovering pyrrhotite provided by the present invention does not require such treatment and has broad application prospects.

[0028] (5) The first-stage flotation froth concentrate described in step S1 contains Zn < 0.1% and S > 37%, and can be directly used as a sulfur concentrate product.

[0029] (6) The first-stage flotation froth concentrate obtained in step S2 contains Zn < 0.1% and Fe > 59%, meeting the sales requirements of iron concentrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a process flow chart of an embodiment of the present invention;

[0031] Figure 2 This is a conventional flotation separation process flow chart for separation of sphalerite and pyrrhotite;

[0032] Figure 3 On-site production of flotation process for separation of sphalerite and pyrrhotite; DETAILED DESCRIPTION

[0033] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0034] Example 1

[0035] The main metal minerals in the lead-zinc pyrite ore produced by a high-pyrrhotite lead-zinc mine in Qinghai are pyrrhotite, sphalerite, galena and other sulfide minerals. The original ore contains Pb 1.22%, Zn 3.45%, Fe 41.22%, S25.17%. The mine adopts lead priority flotation-lead flotation tailings activated zinc flotation method to treat the ore. The composition and relative content of each mineral in the lead flotation tailings are shown in Table 1.

[0036] Table 1 Composition and relative content of minerals in lead tailings

[0037]

[0038] As can be seen from Table 1, the main mineral in the material (lead tailings) used for separation of sphalerite and pyrrhotite is pyrrhotite, accounting for 59.28% of the total mineral content, and the target mineral is sphalerite, accounting for 5.3% of the total mineral content. The on-site production adopts a large amount of lime + humic acid to strongly inhibit pyrrhotite to float sphalerite. Due to the high content of pyrrhotite in the lead tailings, the consumption of copper sulfate reaches 1600g / t. The production process is as follows: Figure 3 The mineral processing indicators of on-site flotation separation of sphalerite and pyrrhotite are shown in Table 2.

[0039] Table 2 Separation index of sphalerite and pyrrhotite in on-site production (%)

[0040]

[0041] According to the attached Figure 1 The process flow shown in the figure treats the lead tailings, and the treatment steps include:

[0042] (1) The raw ore is crushed and ground to 74 μm, accounting for 90%; the ore is thickened to a mass percentage concentration of 40% using a thickener, and the thickened slurry is transported to a slurry mixing tank for mixing;

[0043] (2) The lead tailings are transported to a flotation machine, and 5 g / t of methyl isobutyl carbinol or ethanol ether is added to perform aeration flotation. After a roughing operation, sulfur concentrate 1 and flotation tailings 1 are obtained. The flotation tailings 1 flow by gravity to the next-stage flotation machine. The sulfur concentrate 1 produced contains 59.22% of Fe, 37.21% of S, and 0.054% of Zn. The sulfur concentrate 1 is directly used as an iron concentrate product;

[0044] (3) The flotation tailings 1 produced in step (2) are sequentially added with 100 g / t of oxalic acid or citric acid and 30 g / t of methyl isobutyl carbinol or ethanol ether for aeration flotation. After a roughing operation, sulfur concentrate 2 and flotation tailings 2 are obtained. The flotation tailings 2 flow by gravity to the next-stage flotation machine. The sulfur concentrate 2 produced contains 55.21% of Fe, 33.23% of S and 0.53% of Zn.

[0045] (4) 100 g / t of ferrous sulfate, 10 g / t of ethyl sodium xanthate, and 40 g / t of methyl isobutyl carbinol or ethanol ether are sequentially added to the flotation tailings 2 produced in step (3) for aeration flotation. After a roughing operation, sulfur concentrate 3 and flotation tailings 3 are obtained. The flotation tailings 3 flow by gravity to the next-stage flotation machine.

[0046] (5) The flotation tailings 3 produced in step (4) are sequentially added with 80 g / t of copper sulfate, 250 g / t of lime, 60 g / t of butyl sodium xanthate or amyl potassium xanthate, and 15 g / t of methyl isobutyl carbinol or ethanol ether for aeration flotation. After a roughing operation, a foam concentrate 1 and a tank bottom tailing are obtained. The foam concentrate 1 is added with 150 g / t of lime for concentrating. The concentrate product after the concentrating operation is zinc concentrate. The concentrating tailings are combined with the sulfur concentrate 2 produced in step (3) and returned to the roughing operation. A first scavenging operation is carried out by adding 20 g / t of butyl sodium xanthate or amyl potassium xanthate to the bottom tailings to obtain a first scavenging concentrate and a first scavenging tailings. The first scavenging concentrate and the selected tailings are combined with the sulfur concentrate 2 produced in step (3). A second scavenging operation is carried out by adding 20 g / t of butyl sodium xanthate or amyl potassium xanthate to the first scavenging tailings to obtain a second scavenging concentrate and a second scavenging tailings. The second scavenging concentrate is combined with the sulfur concentrate 3 produced in step (4) and returned to the first scavenging. The second scavenging tailings are the final flotation tailings.

[0047] Use attached Figure 1 The indicators obtained by the process shown are shown in Table 3;

[0048] Table 3 Beneficiation index of a lead tailings in Qinghai treated by cascade flotation process (%)

[0049]

[0050] The obtained sulfur concentrate 1 contains 59.22% Fe, 37.21% S, and 0.054% Zn. The sulfur concentrate 1 is directly used as an iron concentrate product. The obtained zinc concentrate contains 49.11% Zn, and the Zn recovery rate is 93.22%.

[0051] Comparing Table 3 with Table 2, it can be clearly seen that by using the cascade flotation process recommended by the present invention to treat the lead tailings of a mine in Qinghai, the Zn content of the zinc concentrate increased from 30.22% to 49.11%, and the Zn recovery rate in the zinc concentrate increased from 82.35% to 93.22%. At the same time, through cascade flotation, an iron concentrate product with a yield of 21.80% was produced in step (2), which greatly increased the product value and comprehensive utilization value of the mine. More importantly, compared with the on-site production process Figure 3 Using the process of the present invention, the amount of copper sulfate used in zinc flotation is reduced from 1600g / t to 80g / t, a decrease of 95%, and the amount of lime used in the whole process is reduced from 6000g / t to 400g / t, a decrease of 93.33%. Figure 1 The process flow shown in the figure can process the mixed material containing sphalerite and pyrrhotite, which can significantly reduce the difficulty of separating sphalerite and pyrrhotite and has a significant separation effect.

[0052] Example 2

[0053] A high-pyrrhotite copper-zinc mine in Yunnan uses a preferential copper flotation process to process the raw ore. The copper flotation tailings contain Zn1.6%, Fe 38.22%, and S 20.14%. Through MLA analysis of the copper flotation tailings, it is known that the main mineral in the copper flotation tailings is pyrrhotite, which accounts for about 50% of the total mineral content, followed by sphalerite, which accounts for 2.43% of the total mineral content. Due to the presence of a large amount of pyrrhotite in the tailings, the separation is difficult. There is no mineral processing process for recovering zinc on site, resulting in a large amount of zinc metal being directly discharged into the on-site tailings pond. Figure 1 The cascade flotation process shown is used to treat the copper tailings produced by the mine. The processing steps include:

[0054] (1) crushing and grinding the raw ore to 74 μm, accounting for 85%; concentrating the ore to a slurry mass concentration of 45%, and mixing the slurry;

[0055] (2) conveying the copper tailings to a flotation machine, adding 10 g / t of methyl isobutyl carbinol or ethanol ether, and performing aeration flotation. After a roughing process, sulfur concentrate 1 and flotation tailing 1 are obtained. The flotation tailing 1 flows by gravity to a flotation machine at the next stage. The sulfur concentrate 1 contains 59.22% of Fe, 38.11% of S, and 0.021% of Zn.

[0056] (3) 150 g / t of oxalic acid or citric acid and 20 g / t of methyl isobutyl carbinol or ethanol ether are added to the flotation tailings 1 produced in step (2) for aeration flotation. After a roughing operation, sulfur concentrate 2 and flotation tailings 2 are obtained. The flotation tailings 2 flow by gravity to the next-stage flotation machine. The sulfur concentrate 2 contains 56.21% of Fe, 33.21% of S, and 0.27% of Zn.

[0057] (4) 200 g / t of ferrous sulfate, 20 g / t of ethyl sodium xanthate, and 50 g / t of methyl isobutyl carbinol or ethanol ether are added to the flotation tailings produced in step (3) in sequence for aeration flotation. After a roughing operation, sulfur concentrate 3 and flotation tailings 3 are obtained. The flotation tailings 3 flow by gravity to the next-stage flotation machine.

[0058] (5) The flotation tailings 3 produced in step (4) are sequentially added with 120 g / t of copper sulfate, 300 g / t of lime, 80 g / t of butyl sodium xanthate or amyl potassium xanthate, and 10 g / t of methyl isobutyl carbinol or ethanol ether to perform aeration flotation. After a roughing operation, a foam concentrate 1 and a bottom tailing are obtained. The foam concentrate 1 is added with 150 g / t of lime for a concentration operation. The concentrate product after the concentration operation is a zinc concentrate. The concentrated tailings are returned to the roughing operation, and the bottom tailings are A first scavenging operation is performed by adding 10 g / t of butyl sodium xanthate or amyl potassium xanthate to obtain a first scavenging concentrate and a first scavenging tailing. The first scavenging concentrate is combined with the selected tailings. A second scavenging operation is performed by adding 10 g / t of butyl sodium xanthate or amyl potassium xanthate to the first scavenging tailings to obtain a second scavenging concentrate and a second scavenging tailing. The second scavenging concentrate is combined with the sulfur concentrate 3 produced in step (4) and returned to the first scavenging operation. The second scavenging tailings are the final flotation tailings.

[0059] Use attached Figure 1 The indicators obtained by treating the floating copper tailings of a high-pyrrhotite copper-zinc mine in Yunnan by the process shown in Table 4.

[0060] Table 4 Beneficiation index of a copper tailings in Yunnan treated by cascade flotation process (%)

[0061]

[0062] The obtained sulfur concentrate 1 + sulfur concentrate 2 are combined into a total iron concentrate, which contains Fe>57%, S>35%, and Zn<0.2%, and can be directly sold as an iron concentrate. The zinc concentrate contains 49.31% Zn, and the Zn recovery rate is 93.85%, realizing the comprehensive recovery of the zinc metal resources that are originally unrecoverable in the mine.

[0063] From the results of the embodiments, it can be seen that after the implementation of the present invention, the difficulty of separating the mixed material of iron-containing sphalerite and pyrrhotite can be greatly reduced, the grade of zinc concentrate can be improved, the actual consumption of copper sulfate and lime can be greatly reduced, and the comprehensive recovery of zinc resources in some mines that are difficult to treat and separate can be achieved, with significant economic benefits, so it can be promoted for use.

[0064] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A method for separating sphalerite and pyrrhotite by a cascade flotation process, characterized in that: The following steps are involved: S1. The materials containing sphalerite and pyrrhotite are transported to a slurry mixing tank for mixing and slurry mixing. During the slurry mixing process, the slurry mass concentration is adjusted to 40% to 45% by concentrating or adding clean water for dilution; S2, adding alcohol frother to the ore pulp in step S1 and then aerating flotation, the flotation number is one roughing operation, and the roughing operation obtains the first-stage flotation froth concentrate and the first-stage flotation tailings; S3, adding activator 1 and alcohol frother in turn to the first-stage flotation tailings obtained in step S2, and then aerating flotation, the flotation times are one roughing operation, and the second-stage flotation froth concentrate and the second-stage flotation tailings are obtained by roughing; the activator 1 is one of oxalic acid and citric acid, and the amount is 100g / t to 150g / t; the activator 1 is used to activate pyrrhotite; S4, adding activator 2, collector 1, and alcohol frother in turn to the second-stage flotation tailings obtained in step S3, and then aerating flotation, the flotation times are one roughing operation, and the third-stage flotation froth concentrate and the third-stage flotation tailings are obtained by roughing; the activator 2 is ferrous sulfate, and the amount is 100g / t to 200g / t; the activator 2 is used to activate pyrrhotite; S5, adding pyrrhotite inhibitor, activator 3, collector 2 and alcohol frother in sequence to the third flotation tailings obtained in step S4 and then aerating flotation, the flotation times are one roughing operation, the roughing operation obtains foam concentrate 1 and bottom tailings, the foam concentrate 1 is then added with pyrrhotite inhibitor for concentrating operation, the final foam concentrate after concentrating 1-2 times is zinc concentrate, the concentrating tailings and the second foam concentrate obtained in step S2 are combined and returned to the roughing operation in step S5, the bottom tailings are added with collector 2 for two scavenging operations, the scavenged concentrate 1 obtained in the first scavenging is combined with the concentrating tailings and returned to the roughing operation in step S5, the scavenged concentrate 2 obtained in the second scavenging is combined with the third flotation foam concentrate obtained in step S4 and returned to the first scavenging operation, forming a complete closed-loop cycle operation, the bottom tailings of the second scavenging are the final tailings; the activator 3 is used to activate sphalerite.

2. The method for separating sphalerite and pyrrhotite by a step flotation process according to claim 1, characterized in that: The iron-containing sphalerite and pyrrhotite material in step S1 is 85% to 90% of the iron-containing sphalerite and pyrrhotite raw ore that has been crushed and ground to 74 μm.

3. The method for separating sphalerite and pyrrhotite by a step flotation process according to claim 1, characterized in that: The mass percentage of zinc in the sphalerite and pyrrhotite material containing iron in step S1 is 1.6% to 3.45%, and the main sulfide mineral component type in the sphalerite and pyrrhotite material containing iron is pyrrhotite, followed by sphalerite, the pyrrhotite mineral content accounts for 50% to 59.28% of the total mineral content in the material to be processed, and the sphalerite content accounts for 2.43% to 5.30% of the total mineral content in the material to be processed.

4. The method for separating sphalerite and pyrrhotite by a cascade flotation process according to claim 1, characterized in that: The alcohol foaming agent described in steps S2, S3, S4 and S5 is one of ethanol ether and methyl isobutyl carbinol, and the amount used in step S2 is 5 g / t to 10 g / t, the amount used in step S3 is 20 g / t to 30 g / t, the amount used in step S4 is 40 g / t to 50 g / t, and the amount used in step S5 is 10 g / t to 15 g / t.

5. The method for separating sphalerite and pyrrhotite by a cascade flotation process according to claim 1, characterized in that: The collector 1 described in step S4 is ethyl sodium xanthate, and the dosage is 10 g / t to 20 g / t.

6. The method for separating sphalerite and pyrrhotite by a cascade flotation process according to claim 1, characterized in that: The activator 3 described in step S5 is copper sulfate, and the dosage is 80g / t-120g / t. The pyrrhotite inhibitor described in step S5 is lime, and the roughing dosage is 250g / t-300g / t, and the fine dosage is 150g / t. The collector 2 described in step S5 is one of butyl sodium xanthate and amyl potassium xanthate, and the roughing dosage is 60g / t-80g / t, and the scavenging dosage is 10g / t-20g / t.

7. The method for separating sphalerite and pyrrhotite by a cascade flotation process according to claim 1, characterized in that: When the second-stage flotation foam concentrate in step S3 contains Fe>55%, the produced second-stage flotation foam concentrate contains Zn<0.5%, and can be directly combined with the first-stage flotation foam concentrate in step S2; the produced second-stage flotation foam concentrate contains Zn>0.5%, the second-stage flotation foam concentrate is combined with the selected tailings, and the third-stage flotation foam concentrate produced in step S4 is combined with the scavenging concentrate produced in step S5, so as to form a complete flotation closed-loop process, and realize the complete separation of sphalerite and pyrrhotite.

8. The method for separating sphalerite and pyrrhotite by a step flotation process according to claim 1, characterized in that: The first-stage flotation froth concentrate described in step S1 contains Zn<0.1% and S>37%.

9. The method for separating sphalerite and pyrrhotite by a cascade flotation process according to claim 1, characterized in that: The first-stage flotation froth concentrate obtained in step S2 contains Zn<0.1% and Fe>59%.

10. The method for separating sphalerite and pyrrhotite by a cascade flotation process according to claim 6, characterized in that: The iron-containing sphalerite and pyrrhotite materials processed in steps S1 to S5 produce a zinc concentrate containing Zn>49%.

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