A method for flotation of surface deeply oxidized pyrite by copper ion-coordinated sulfide activation

Abstract

The present invention discloses a method for the flotation of surface deeply oxidized pyrite by copper ion coordinated sulfide activation. The method comprises the following steps: placing a pyrite sample after surface deep oxidation in a flotation tank and adding water to prepare a slurry of a certain concentration. The slurry is stirred for a certain time within a suitable pH range. A certain concentration of copper ion solution is added to fully react with the pyrite surface to generate a Cu-S component with good hydrophobicity. A certain concentration of a sulfiding agent, a collecting agent and a frother are then added in sequence to perform aeration flotation, and the flotation scraping time is controlled. The obtained foam product is filtered and dried to obtain a final sulfur concentrate. The present invention can achieve the purpose of strengthening the activation flotation recovery of surface deeply oxidized pyrite.

Description

Technical Field

[0001] The invention relates to the technical field of sulfide ore flotation recovery, and in particular to a method for flotation of surface deeply oxidized pyrite using copper ions in concert with sulfide activation. Background Art

[0002] In recent years, the amount of tailings stored has increased year by year. Among these tailings, metal sulfide tailings account for the vast majority, and pyrite is the most common and abundant metal sulfide tailings.

[0003] The accumulation of pyrite tailings not only occupies a large amount of storage land, but also causes a series of environmental problems due to its oxidation, such as the formation of acid mine drainage, which also affects the recycling of water used in mineral processing.

[0004] Flotation is a commonly used method for recovering oxidized pyrite. During the oxidation process, the surface properties of pyrite change significantly with increasing oxidation time, significantly impacting pyrite flotation recovery. In the initial oxidation stage, a large amount of hydrophobic components such as elemental sulfur and polysulfides are generated on the pyrite surface, increasing its surface hydrophobicity and facilitating collector-free flotation. However, after extensive surface oxidation, a highly stable oxide layer forms on the pyrite surface. This layer, composed primarily of hydrophilic components such as iron oxides, hydroxides, and sulfates, significantly impedes collector adsorption and significantly reduces its floatability. To recover oxidized pyrite, activated flotation under strongly acidic conditions is currently the most common method. However, this method has several drawbacks, including high acid consumption, difficulty in directly reusing wastewater, high production costs, and stringent equipment requirements. Therefore, developing new flotation technologies to efficiently recover deeply oxidized pyrite is crucial for protecting the ecological environment and promoting the sustainable development of mineral resources. Summary of the Invention

[0005] In order to overcome the above technical problems, the object of the present invention is to provide a method for the flotation of surface deeply oxidized pyrite by copper ion synergistic sulfide activation. The method comprises stirring the surface deeply oxidized pyrite under weak acid conditions for a certain period of time to reduce the stability of the pyrite surface oxide layer and increase the surface active sites of the pyrite. Then, a certain concentration of copper ion and sulfiding agent solution is added. Under the synergistic effect of copper ions and sulfur ions, the hydrophobicity of the pyrite surface is greatly improved, thereby achieving the purpose of strengthening the activation flotation recovery of the surface deeply oxidized pyrite.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for flotation of surface deeply oxidized pyrite by copper ion-coordinated sulfide activation comprises the following steps:

[0008] The pyrite with deep surface oxidation is placed in a flotation tank and water is added to prepare a slurry of a certain concentration. The slurry is stirred for a certain period of time within an appropriate pH range, and a copper ion solution is added to allow it to fully react with the pyrite surface to generate a Cu-S component with good hydrophobicity. Then, a certain concentration of sulfiding agent, collector and frother are added in sequence to carry out aeration flotation, and the flotation scraping time is controlled. The obtained foam product is filtered and dried to obtain the final sulfur concentrate.

[0009] The deep surface oxidation refers to the generation of a large amount of highly hydrophilic iron oxides or hydroxides on the surface of pyrite after the reaction with O2 and H2O. The floatability of pyrite is poor, and it is difficult to flotation and recover it by adding only xanthogenic acid collector.

[0010] The pyrite sample has a particle size of less than 74 microns, a pulp concentration within the range of 10% to 35%, a weak acid system with a pH value of 4-6.5, a stirring intensity of 1700 to 2000 r / min, and a stirring time of 3 to 8 minutes.

[0011] The copper ion solution is a copper sulfate solution, and the amount added is 200-400 g / t relative to the amount of the original ore. The stirring time after adding the copper ions is 3-5 minutes.

[0012] The sulfiding agent is sodium sulfide solution, the amount of the sulfiding agent relative to the original ore is 500-1500g / t, and the sulfiding stirring time is 3-10min.

[0013] The collector is butyl xanthate, and the amount of the collector relative to the original ore is 50-250 g / t. The foaming agent is pine oil emulsion, and the amount of the foaming agent relative to the original ore is 20-60 g / t. After adding the collector and foaming agent, the stirring time is 3 minutes and 2 minutes respectively.

[0014] During the aeration flotation, the aeration time is 1 to 3 minutes, and the flotation scraping time interval is once every 10 seconds.

[0015] Beneficial effects of the present invention:

[0016] The present invention stirs deeply oxidized pyrite under weak acid conditions for a certain period of time to reduce the stability of the pyrite's surface oxide layer and increase the active sites on the pyrite surface. A certain concentration of copper ion and sulfiding agent solution is then added. The synergistic effect of the copper and sulfiding agents significantly improves the pyrite's surface hydrophobicity, achieving the goal of enhancing the activated flotation recovery of deeply oxidized pyrite. Compared with flotation of deeply oxidized pyrite without the addition of copper ions and sulfiding agent, the recovery rate is increased by 56% to 77%. The present invention is highly targeted, employing conventional reagents, resulting in low reagent costs. Furthermore, the present invention has low operating requirements and strong adaptability, addressing the issues of high reagent usage and low recovery rates associated with conventional flotation of deeply oxidized pyrite. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to the embodiments.

[0018] In the following examples, the particle size of the pyrite samples was all below 74 μm.

[0019] The copper sulfate and sulfiding agent used were of analytical grade, while the collector and frother were of industrial grade. All reagent solutions used in the experiment were prepared with deionized water to the corresponding concentrations, and the sulfiding agent and collector solutions were prepared fresh for use.

[0020] The foaming agent solution is prepared by dropping pine oil into a volumetric flask containing a certain amount of deionized water, performing ultrasonic emulsification until the pine oil is completely dissolved, and then adjusting the volume to the corresponding scale line to obtain a pine oil emulsion for use.

[0021] Example 1

[0022] The invention discloses a method for flotation of surface deeply oxidized pyrite by using copper ions in combination with sulfidation activation. The method comprises the following steps: placing the surface deeply oxidized pyrite in a flotation tank, adding water to prepare a slurry with a concentration of 35%, stirring the slurry for 5 minutes at a pH of 4.5, adding 200 g / t of a copper ion solution to fully react the solution with the pyrite surface to generate a Cu-S component with good hydrophobicity, sequentially adding 1500 g / t of a sulfiding agent, 100 g / t of butyl xanthate, and 40 g / t of pine oil, stirring the solution for 5 minutes, 3 minutes, and 2 minutes, respectively, and performing aeration flotation. The flotation frothing time is controlled to be 5 minutes. The obtained foam product is filtered and dried, and finally the surface deeply oxidized pyrite recovery rate is 61.25%.

[0023] Example 2

[0024] A method for flotation of surface deeply oxidized pyrite by copper ion coordinated sulfidation activation comprises the following steps: placing the surface deeply oxidized pyrite in a flotation tank, adding water to prepare a slurry with a concentration of 20%, stirring for 5 minutes under a pH value of 4.5, adding 340 g / t of a copper ion solution to fully react with the pyrite surface to generate a Cu-S component with good hydrophobicity; then sequentially adding 1000 g / t of a sulfiding agent, 100 g / t of butyl xanthate, and 40 g / t of pine oil, stirring for 5 minutes, 3 minutes, and 2 minutes, respectively, to perform aeration flotation, and controlling the flotation foam scraping time to be 5 minutes; filtering and drying the obtained foam product, and finally obtaining a surface deeply oxidized pyrite with a recovery rate of 82.26%.

[0025] Example 3

[0026] The invention discloses a method for flotation of surface deeply oxidized pyrite by using copper ions in combination with sulfidation activation. The method comprises the following steps: placing the surface deeply oxidized pyrite in a flotation tank, adding water to prepare a slurry with a concentration of 20%, stirring the slurry for 5 minutes at a pH of 5.8, adding 200 g / t of a copper ion solution to fully react the solution with the pyrite surface to generate a Cu-S component with good hydrophobicity, sequentially adding 1000 g / t of a sulfiding agent, 100 g / t of butyl xanthate, and 40 g / t of pine oil, stirring the solution for 8 minutes, 3 minutes, and 2 minutes, respectively, and performing aeration flotation. The flotation frothing time is controlled to be 5 minutes. The obtained foam product is filtered and dried, and the recovery rate of the surface deeply oxidized pyrite is finally 75.81%.

[0027] Example 4

[0028] A method for flotation of deeply oxidized pyrite using copper ions in combination with sulfidation activation is similar to Example 2, except that during the flotation of the deeply oxidized pyrite, the pH value of the slurry is controlled at 5.8, and then copper ions, a sulfiding agent solution, a collector, and a frother are sequentially added before flotation. The final recovery rate of the deeply oxidized pyrite is 65.93%.

[0029] Example 5

[0030] A method for flotation of surface deeply oxidized pyrite using copper ions in combination with sulfidation activation is the same as Example 2, except that no copper ion and sulfiding agent solution is added, and flotation is performed after adding a collector and a frother. The final recovery rate of the surface deeply oxidized pyrite is only 5.21%.

[0031] The principle of the present invention is:

[0032] When the pyrite surface is unoxidized, copper ions are easily adsorbed on the pyrite surface and, through replacement and redox reactions, the pyrite surface components are converted into Cu-S components, thereby increasing the pyrite flotation activity. However, after deep oxidation of the pyrite surface, the generation of a large number of hydrophilic components leads to a significant reduction in the active sites available for copper ions to react, making it difficult for copper ions to activate. Under weak acid conditions, the stability of the pyrite surface oxide layer decreases, exposing active sites for copper ion adsorption. For most copper sulfide minerals, after surface oxidation, sulfiding agents are often used as activators to improve their surface hydrophobicity. Due to the adsorption of copper ions, a certain amount of Cu-S components will be present on the pyrite surface, providing favorable conditions for the action of sulfide ions. The addition of sulfiding agents will prevent further oxidation of the mineral surface, thereby achieving the purpose of enhancing the activation flotation recovery of deeply oxidized pyrite.

Claims

1. A method for flotation of surface deeply oxidized pyrite by copper ion-coordinated sulfide activation, characterized in that: The steps include: The pyrite with deep surface oxidation is placed in a flotation tank and water is added to prepare a certain concentration of slurry. The slurry is stirred for a certain period of time within an appropriate pH range. A copper ion solution is added to allow it to fully react with the pyrite surface to generate a Cu-S component with good hydrophobicity. Then, a certain concentration of sulfiding agent, collector and frother are added in sequence to carry out aeration flotation, and the flotation scraping time is controlled. Filtering and drying the obtained foam product to obtain the final sulfur concentrate; The pyrite sample has a particle size of less than 74 microns, a slurry concentration of 10% to 35%, a slurry solution with a pH value of 4-6.5 and a weak acid system, a stirring intensity of 1700 to 2000 r / min, and a stirring time of 3 to 8 minutes; The copper ion solution is a copper sulfate solution, the amount of which is 200 to 400 g / t relative to the amount of the original ore, and the stirring time after adding the copper ions is 3 to 5 minutes; The sulfiding agent is sodium sulfide solution, the amount of the sulfiding agent relative to the original ore is 500-1500g / t, and the sulfiding stirring time is 3-10min.

2. The method for flotation of surface deeply oxidized pyrite by copper ion-coordinated sulfide activation according to claim 1, characterized in that: The deep surface oxidation refers to the generation of a large amount of highly hydrophilic iron oxides or hydroxides on the surface of pyrite after the reaction with O2 and H2O. The floatability of pyrite is poor, and it is difficult to flotation and recover it by adding only xanthogenic acid collector.

3. The method for flotation of surface deeply oxidized pyrite by copper ion coordinated sulfide activation according to claim 1, characterized in that: The collector is butyl xanthate, and the amount of the collector relative to the original ore is 50-250 g / t. The foaming agent is pine oil emulsion, and the amount of the foaming agent relative to the original ore is 20-60 g / t. After adding the collector and foaming agent, the stirring time is 3 minutes and 2 minutes respectively.

4. The method for flotation of surface deeply oxidized pyrite by copper ion-coordinated sulfide activation according to claim 1, characterized in that: During the aeration flotation, the aeration time is 1 to 3 minutes, and the flotation scraping time interval is once every 10 seconds.