A method for activating flotation to recover pyrite from high-sulfur copper tailings

Abstract

This invention discloses a method for activating flotation and recovering pyrite from high-sulfur copper tailings, belonging to the field of mineral beneficiation technology. First, the high-sulfur copper tailings are deslimed. Then, acidic silica gel (a mixture of sulfuric acid, acidic wastewater, and water glass) is added to the deslimed slurry as an activator. Ethyl xanthate, isobutyl xanthate, and isopentyl xanthate are used as collector I, and No. 2 oil is used as a frother. Under a three-stage flotation process (one roughing, three scavenging, and three cleaning), a high-sulfur concentrate is obtained with a high sulfur recovery rate. This method overcomes the disadvantages of sulfuric acid (high corrosiveness and risk) and acidic wastewater (instability), offering advantages such as good activation effect, low cost, low risk, environmental friendliness, and wide applicability, enabling efficient flotation recovery of pyrite.

Description

Technical Field

[0001] This invention relates to a method for activating flotation to recover pyrite from high-sulfur copper tailings, specifically relating to the field of mineral separation technology. Background Technology

[0002] Pyrite is one of the main gold-bearing minerals, often associated with copper, lead, and zinc sulfide minerals, and flotation is a commonly used separation method. Due to its low economic value, lime is often used industrially as a pyrite suppressant to recover other high-value metals under highly alkaline conditions, leaving pyrite often unrecovered in tailings. However, sulfur-containing tailings undergo natural oxidation during storage, easily generating large amounts of acidic wastewater, leading to serious environmental problems and high remediation costs. Therefore, the economical and efficient recovery of pyrite from tailings resources is of great significance for environmental protection and resource reuse.

[0003] Currently, sulfuric acid, copper sulfate, ammonium salts, and mine acid water are widely used as activators for pyrite inhibited by lime, and their industrial applications are relatively mature, but they have many drawbacks. Sulfuric acid has the advantages of low cost, good activation effect, and easy production, but it also has disadvantages such as strong corrosiveness and high use risks. Copper sulfate and ammonium salt activators have good activation performance, but copper sulfate is expensive and involves subsequent heavy metal wastewater treatment; ammonium salt activators also pose environmental pollution risks. However, their sources are unstable; reserves are low in the dry season, with a pH of 2-3, and they are highly corrosive; reserves are abundant in the rainy season, with a pH of 4-5, and their activation ability is weaker. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an economical and efficient method for pyrite activation and recovery, taking copper tailings suppressed by high-alkali lime as an example, thereby achieving comprehensive utilization of mine acidic wastewater and sulfur-containing tailings.

[0005] The technical solution of the present invention is: a method for activating flotation to recover pyrite in high-sulfur copper tailings, wherein the activator in the flotation process is acidic silica gel.

[0006] Preferably, the activator is added at a ratio of 2000-3000 g / t using water glass (the amount of water glass added to each ton of slurry is 2000-3000 g).

[0007] Preferably, the acidic silica gel is prepared as follows: sulfuric acid is added to acidic wastewater to prepare a mixed acid solution. When the pH of the mixed acid solution is 1-2, the addition of sulfuric acid is stopped. The concentration of sulfuric acid used is 10-20%. Then, water glass is added to the mixed acid solution and mixed evenly. When the pH of the solution is 5-6, the addition of water glass is stopped. The concentration of water glass used is 40%.

[0008] Preferably, the acidic wastewater originates from acidic wastewater generated by rainfall in open-pit sulfide mines, and the properties of the acidic wastewater differ significantly between dry and rainy seasons.

[0009] Preferably, the recycling method specifically includes the following steps:

[0010] (1) Deslim the copper tailings and adjust the pH to 8-9 using an activator under the original pH conditions.

[0011] (2) Collector I and frother are added to the slurry in sequence, and sulfur concentrate and tailings are obtained through a process of roughing, scavenging and cleaning.

[0012] Preferably, in step (1), the collector I is composed of ethyl xanthate, isobutyl xanthate and isopentyl xanthate, wherein the mass ratio of ethyl xanthate, isobutyl xanthate and isopentyl xanthate is 3:5:2, the collector is prepared as a 1% mass concentration aqueous solution and added, and the addition ratio of collector I is 150-250g / t.

[0013] Preferably, the foaming agent in step (1) is No. 2 oil, and the addition ratio is 30-50g / t.

[0014] Preferably, in step (1), the coarse selection operation takes 5-6 minutes, the sweeping operation takes 5-6 minutes, and the fine selection operation takes 4-5 minutes.

[0015] Preferably, the high-sulfur copper tailings are copper tailings suppressed by high-alkali lime.

[0016] The experimental principle of this invention is as follows: Acidic silica gel, prepared from sulfuric acid, acidic wastewater, and water glass, has the following effect in a high-alkali flotation environment where lime inhibits the flotation of pyrite:

[0017] (1) Lower the flotation pH value to restore the flotation activity of pyrite.

[0018] (2) Acidic silica gel contains a large amount of SO4. 2- H2SiO3 can remove Ca from the surface of pyrite and the flotation solution. 2+ Precipitation helps to relieve depression.

[0019] (3) Acidic wastewater contains Cu 2+ Fe 3+ Zn 2+ Active ions can be adsorbed on the surface of pyrite, thereby promoting its flotation.

[0020] (4) SiO3 2- It has good dispersibility, which helps to produce high-quality sulfur concentrate.

[0021] (5) Acidic wastewater contains active ions, water glass contains silicate ions, and sulfuric acid contains sulfate ions, which have a synergistic effect.

[0022] Beneficial effects of the present invention

[0023] (1) The activator used in this invention is acidic silica gel, which solves the disadvantages of strong corrosiveness of sulfuric acid, high risk of use and instability of acidic wastewater. It can efficiently activate pyrite under low cost and low risk conditions.

[0024] (2) This invention is designed for high-sulfur copper tailings that are suppressed by lime, effectively solving the environmental problem of acidic wastewater in mines, while bringing considerable economic benefits to enterprises. It has multiple significances of environmental protection and secondary utilization of resources.

[0025] (3) The activator used in this invention is acidic silica gel. The synergistic effect between the agents is strong, and the activation effect on pyrite is significant, which can produce high-quality sulfur concentrate. Attached Figure Description

[0026] Figure 1 Flotation process flow chart. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0028] Example 1

[0029] Mineral raw materials

[0030] The reagents were taken from high-sulfur copper tailings after desliming at a copper concentrator in Yunnan Province. The pH value was ≥12 and the sulfur grade was 10-11%. The pyrite was mainly present as pyrite, and the gangue minerals were mainly quartz and aluminosilicates. The reagent dosages are shown in Table 1.

[0031] Table 1. Dosage of medicine in Example 1

[0032]

[0033] The specific operating steps are as follows:

[0034] (1) Add sulfuric acid to acidic wastewater at a concentration of 15%. Stop adding sulfuric acid when the solution pH = 2 to obtain mixed acid water.

[0035] (2) Prepare water glass to a concentration of 40% and add it to the mixed acid water obtained in step (1). Stop adding water glass when the pH of the solution is 6 to obtain acidic silica gel, which is the activator.

[0036] (3) Deslim the copper tailings and adjust the pH to 8 using acidic silica gel as an activator under the original pH conditions.

[0037] (4) Collector I and No. 2 oil, composed of ethyl xanthate, isobutyl xanthate and isoamyl xanthate, are added sequentially to the copper tailings obtained in step (3). After one roughing operation with a roughing operation time of 6 minutes, three scavenging operations with a scavenging operation time of 6 minutes each, and three cleaning operations without adding any reagents with a cleaning operation time of 4 minutes each, sulfur concentrate is obtained. The intermediate products are returned in sequence. The product indicators are shown in Table 2.

[0038] Table 2. Flotation Product Indicators of Example 1

[0039] Work Products Yield (%) grade(%) Recovery rate (%) Concentrate 19.90 48.32 90.95 Tailings 80.10 1.19 9.05 raw ore 100.00 10.57 100.00

[0040] As shown in Table 2, after desliming, the high-sulfur copper tailings underwent a process of one roughing, three scavenging, and three cleaning steps. Using acidic silica gel as an activator, the sulfur recovery rate reached 90.95%, achieving a high sulfur recovery rate. The sulfur grade in the sulfur concentrate product reached 48.32%, resulting in high-quality concentrate indicators.

[0041] Example 2

[0042] The mineral raw materials used in this embodiment are the same as those in Example 1, and the dosage of the reagents is shown in Table 3.

[0043] Table 3. Dosage of medicine in Example 2

[0044]

[0045] The specific operating steps are as follows:

[0046] (1) Prepare sulfuric acid to a concentration of 10% and add it to acidic wastewater. Stop adding sulfuric acid when the solution pH=1 to obtain mixed acid water.

[0047] (2) Prepare water glass to a concentration of 40% and add it to the mixed acid water obtained in step (1). Stop adding water glass when the solution pH = 5 to obtain acidic silica gel, which is the activator.

[0048] (3) Deslim the copper tailings and adjust the pH to 9 using acidic silica gel as an activator under the original pH conditions.

[0049] (4) In step (3), collectors I and II, consisting of ethyl xanthate, isobutyl xanthate, and isoamyl xanthate, are added sequentially to the copper tailings. After one roughing operation (5 minutes), three scavenging operations (5 minutes each), and three cleaning operations (5 minutes each) without the addition of any reagents, sulfur concentrate is obtained. Intermediate products are returned in sequence. Product indicators are shown in Table 4.

[0050] Table 4. Flotation Product Indicators of Example 2

[0051] Work Products Yield (%) grade(%) Recovery rate (%) Concentrate 21.17 49.92 92.75 Tailings 78.83 0.97 7.25 raw ore 100.00 10.57 100.00

[0052] As shown in Table 4, after desliming, the high-sulfur copper tailings underwent a process of one coarse, three scavenging, and three cleaning steps. Using acidic silica gel as an activator, the sulfur recovery rate reached 92.75%, achieving a high sulfur recovery rate. The sulfur grade in the sulfur concentrate product reached 49.92%, resulting in high-quality concentrate indicators.

[0053] Example 3

[0054] The mineral raw materials used in this embodiment are the same as those in Example 1, and the dosage of the reagents is shown in Table 5.

[0055] Table 5. Dosage of medicine in Example 3

[0056]

[0057] The specific operating steps are as follows:

[0058] (1) Prepare sulfuric acid to a concentration of 20% and add it to acidic wastewater. Stop adding sulfuric acid when the solution pH = 2 to obtain mixed acid water.

[0059] (2) Prepare water glass to a concentration of 40% and add it to the mixed acid water obtained in step (1). Stop adding water glass when the pH of the solution is 6 to obtain acidic silica gel, which is the activator.

[0060] (3) Deslim the copper tailings and adjust the pH to 9 using acidic silica gel as an activator under the original pH conditions.

[0061] (4) Collector I and No. 2, composed of ethyl xanthate, isobutyl xanthate and isoamyl xanthate, are added sequentially to the copper tailings obtained in step (3). After one roughing operation with a roughing operation time of 5 minutes, three scavenging operations with a scavenging operation time of 5 minutes each, and three cleaning operations without adding any reagents with a cleaning operation time of 5 minutes each, sulfur concentrate is obtained. The intermediate products are returned in sequence. The product indicators are shown in Table 6.

[0062] Table 6. Flotation Product Indicators of Example 3

[0063] Work Products Yield (%) grade(%) Recovery rate (%) Concentrate 19.73 49.12 91.68 Tailings 80.27 1.10 8.32 raw ore 100.00 10.57 100.00

[0064] As shown in Table 6, after desliming, the process of this high-sulfur copper tailings, consisting of one roughing, three scavenging, and three cleaning steps, achieved a sulfur recovery rate of 91.68% under the condition of using acidic silica gel as an activator. This indicates a high sulfur recovery rate, with the sulfur grade in the sulfur concentrate reaching 49.12%. High-quality concentrate indicators were obtained.

[0065] Comparative Example 1

[0066] As a comparative example, except that the activator is sulfuric acid, the mineral raw materials and specific operating procedures are the same as in Example 1. The dosage of the reagents is shown in Table 7, and the product indicators are shown in Table 8.

[0067] Table 7 Comparative Example 1 Drug Dosage

[0068]

[0069] Table 8. Flotation product indicators of Comparative Example 1

[0070] Work Products Yield (%) grade(%) Recovery rate (%) Concentrate 20.09 47.58 90.47 Tailings 79.81 1.26 9.53 raw ore 100.00 10.57 100.00

[0071] As shown in Table 8, when sulfuric acid is used as an activator for high-sulfur copper tailings, the sulfur recovery rate in the sulfur concentrate product is 90.47% and the sulfur grade is 47.58%. The results indicate that sulfuric acid can produce higher quality sulfur concentrate. Compared with the flotation results of Examples 1-3, the sulfur grade and recovery rate of the sulfur concentrate are lower, and there is a certain gap with the effect of acidic silica flotation.

[0072] A comparison of Examples 1-3 and Comparative Example 1 reveals that, compared with traditional activated flotation methods, the activated flotation method of the present invention can more effectively achieve high-quality recovery of pyrite from high-sulfur copper tailings. The activator used, acidic silica gel, has a good activation effect, causes less equipment corrosion, and has a low risk of use.

[0073] Comparative Example 2

[0074] As a comparative example, except that the activator is mine acid water (the acidic wastewater used is dry season acidic wastewater), the mineral raw materials and specific operating procedures are the same as in Example 1, the dosage of the reagents is shown in Table 9, and the product indicators are shown in Table 10.

[0075] Table 9 Comparative Example 2 Drug Dosage

[0076]

[0077] The product specifications are shown in Table 10. The dosage of acidic wastewater in the table cannot be accurately determined due to significant differences in its properties between dry and rainy seasons. In the experiment, only a pH of 8 in the copper tailings desliming slurry is required.

[0078] Table 10. Flotation product indicators of Comparative Example 2

[0079] Work Products Yield (%) grade(%) Recovery rate (%) Concentrate 20.44 47.24 91.36 Tailings 79.56 1.15 8.64 raw ore 100.00 10.57 100.00

[0080] As shown in Table 10, when acidic wastewater was used as an activator for high-sulfur copper tailings, the sulfur recovery rate in the sulfur concentrate product was 91.36% and the sulfur grade was 47.24%. The results indicate that acidic wastewater as an activator can produce higher quality sulfur concentrate. Compared with the flotation results of Examples 1-3, the sulfur grade of the sulfur concentrate decreased, the recovery rate decreased, and the recovery effect was somewhat different from that of acidic silica gel.

[0081] A comparison of Example 3 and Comparative Example 2 revealed that, compared with the traditional activated flotation method, the activated flotation method of the present invention can more effectively achieve high-quality recovery of pyrite from high-sulfur copper tailings. The activator used, acidic silica gel, has good activation effect, is green and environmentally friendly, and has a stable source.

Claims

1. A method for recovering pyrite by activated flotation in high-sulfur copper tailings, characterized in that: The recycling method specifically includes the following steps: (1) Deslim the copper tailings and adjust the pH to 8-9 using an activator under the original pH conditions; (2) Collector I and frother are added to the slurry in sequence, and sulfur concentrate and tailings are obtained through a process of roughing, scavenging and cleaning. The high-sulfur copper tailings are copper beneficiation tailings suppressed by high-alkali lime. The activator during the flotation process is acidic silica gel; The activator is added at a ratio of 2000-3000 g / t, based on the amount of water glass. The acidic silica gel is prepared as follows: sulfuric acid is added to acidic wastewater to prepare a mixed acid solution. When the pH of the mixed acid solution is 1-2, the addition of sulfuric acid is stopped. The concentration of sulfuric acid used is 10-20%. Then, water glass is added to the mixed acid solution and mixed evenly. When the pH of the solution is 5-6, the addition of water glass is stopped. The concentration of water glass used is 40%.

2. The method for activating flotation to recover pyrite from high-sulfur copper tailings according to claim 1, characterized in that: The acidic wastewater originates from acidic wastewater generated by rainfall in open-pit sulfide mines.

3. The method for activating flotation to recover pyrite from high-sulfur copper tailings according to claim 1, characterized in that: In step (2), collector I is composed of ethyl xanthate, isobutyl xanthate and isopentyl yellow, wherein the mass ratio of ethyl xanthate, isobutyl xanthate and isopentyl yellow is 3:5:2, and collector I is prepared as a 1% mass concentration aqueous solution for addition.

4. The method for activating flotation to recover pyrite from high-sulfur copper tailings according to claim 1, characterized in that: In step (2), the foaming agent is No. 2 oil.

5. The method for activating flotation to recover pyrite from high-sulfur copper tailings according to claim 1, characterized in that: In step (2), the roughing operation takes 5-6 minutes, with collector I added at a rate of 150-250 g / t and frother added at a rate of 20-30 g / t; the scavenging operation takes 5-6 minutes, with collector I added at a rate of 30-50 g / t and frother added at a rate of 10-20 g / t in scavenging I, collector I added at a rate of 10-20 g / t in scavenging II, and frother added at a rate of 5-10 g / t in scavenging III; and the finer operation takes 4-5 minutes without the addition of any chemicals.

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