Preparation and application method of environment-friendly pyrite inhibitor

Abstract

The application provides a preparation and application method of an environment-friendly pyrite inhibitor. The application relates to the technical field of flotation reagents in mineral processing engineering. The method comprises the following steps: placing 2-methyl-3-mercaptotetrahydrofuran and cobalt (III) acetate in an acetic acid solution, heating to reflux, filtering, washing the collected filter cake with dilute acetic acid, performing vacuum distillation on the obtained filtrate, and finally placing the product in a high-pressure reaction kettle to react under certain temperature, atmosphere and pressure. Finally, the environment-friendly pyrite inhibitor is obtained. The 2-methyl-3-mercaptotetrahydrofuran is modified through a series of derivatization methods, functional groups are introduced, and the structure is optimized. The environment-friendly pyrite inhibitor prepared in this way can effectively inhibit the pyrite while reducing the amount of lime, thereby avoiding the excessive increase of the pH of the ore pulp. In this way, the concentrate grade can be improved, and the recovery rate of associated elements can be improved, so that the economic benefits and environmental benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of flotation reagents in mineral processing engineering, and in particular to a method for preparing and applying an environmentally friendly pyrite inhibitor. Background Technology

[0002] Pyrite often exists as a by-product in precious and non-ferrous metal ores, and its impact on concentrate grade is significant. During ore processing, concentrate grade is a crucial indicator of the ore's economic value; the presence of pyrite often leads to increased impurities in the concentrate, thereby reducing the concentrate grade and affecting the overall utilization value of the ore.

[0003] Separating pyrite from other valuable sulfides during conventional flotation processes is a significant technical challenge. Due to the similarities in physical and chemical properties between pyrite and other sulfides, they are prone to mixing during flotation, leading to a decrease in concentrate purity. In traditional flotation, lime is the most commonly used and economical depressant for pyrite. However, achieving efficient pyrite suppression often requires a high amount of lime, inevitably increasing the pulp pH. High pH conditions not only corrode flotation equipment but also reduce the recovery rates of associated elements in the ore. Furthermore, in high pH environments, some associated elements may be difficult to recover due to chemical reactions or changes in solubility, reducing resource utilization and potentially impacting the environment. Therefore, developing low-alkalinity, high-efficiency pyrite depressants is crucial.

[0004] In view of this, it is necessary to design an environmentally friendly method for the preparation and application of pyrite inhibitors to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the present invention aims to provide a method for preparing and applying an environmentally friendly pyrite inhibitor. By modifying the properties of the pyrite inhibitor and introducing functional groups, a highly efficient inhibition of pyrite can be achieved in a low-alkalinity slurry system.

[0006] To achieve the above objectives, the present invention provides a method for preparing an environmentally friendly pyrite inhibitor, comprising the following steps:

[0007] S1. Add 2-methyl-3-mercaptofuran and cobalt(III) acetate sequentially to an acetic acid solution;

[0008] S2. The material from step S1 is heated to reflux and then reacted for a first predetermined time. After the reaction is completed, it is filtered while hot and the filter cake is collected. The filter cake is washed repeatedly with dilute acetic acid and the filtrate is collected. The filtrate is then distilled under reduced pressure to obtain product A.

[0009] S3. Add the product A into the high-pressure reactor, purge the air in the system with nitrogen, slowly purge the nitrogen in the system under negative pressure, and then slowly introduce hydrogen until the pressure in the reactor reaches 8-10 MPa, then stop introducing hydrogen.

[0010] S4. After raising the temperature inside the reactor to a predetermined temperature, maintain the temperature at a constant level within the predetermined temperature range for a second predetermined time to obtain an environmentally friendly pyrite inhibitor.

[0011] Further, in step S1, the mass concentration of the acetic acid solution is 20-30%.

[0012] Further, in step S1, the mass ratio of 2-methyl-3-mercaptofuran, acetic acid solution, and cobalt(III) acetate is 20-30:400-500:1.

[0013] Furthermore, in step S2, the heating temperature is 130–150°C; the first predetermined reaction time is 4–10 days; and the washing is repeated 2–3 times.

[0014] Furthermore, in step S3, the high-pressure reactor is equipped with a sponge nickel mesh.

[0015] Furthermore, in step S4, the predetermined temperature is 120–150°C; the second predetermined time is 4–8 hours.

[0016] This invention also provides an application method for the environmentally friendly pyrite inhibitor prepared by the aforementioned preparation method, comprising the following steps:

[0017] Sa, the target ore, lime, and the environmentally friendly pyrite inhibitor are mixed and ground to a predetermined particle size, and then a slurry of predetermined concentration is prepared.

[0018] Sb, Add butyl xanthate and butyl ammonium black powder to the slurry and stir for 2-5 minutes;

[0019] Sc, then add 20g / t of No. 2 oil and stir for 2-5 minutes;

[0020] Sd, and finally flotation for 4-6 minutes to obtain concentrate and tailings.

[0021] Further, in step Sa, the dosage of lime is 500-1000 g / t; the dosage of the environmentally friendly pyrite inhibitor is 200-500 g / t.

[0022] Further, in step Sb, the dosage of the butyl xanthate is 60-150 g / t; the dosage of the butylammonium black powder is 10-50 g / t.

[0023] Furthermore, in step Sc, the dosage of the No. 2 oil is 20-50 g / t.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention provides a method for preparing an environmentally friendly pyrite inhibitor. The method involves reacting 2-methyl-3-mercaptofuran and cobalt(III) acetate in an acetic acid solution by heating to reflux, filtering, repeatedly washing the collected filter cake with dilute acetic acid, distilling the resulting filtrate under reduced pressure, and finally reacting the product in a high-pressure reactor under specific temperature, atmosphere, and pressure conditions to obtain an environmentally friendly pyrite inhibitor. This inhibitor has a cyclic structure and contains both hydrophilic and solid-philic groups. By introducing functional groups through a series of derivatization methods, 2-methyl-3-mercaptofuran is modified and its structure optimized, thereby preparing an environmentally friendly pyrite inhibitor that can be used for highly efficient inhibition of pyrite during flotation.

[0026] 2. This invention provides an application method for an environmentally friendly pyrite inhibitor. When using a specially formulated environmentally friendly pyrite inhibitor for flotation of sulfide ores such as high-sulfur gold-bearing ores and high-sulfur polymetallic ores, this inhibitor, with its oxygen-containing cyclic molecular structure, acts on the active sites on the pyrite mineral surface. The lone pair electrons of the cyclic structure enhance the adsorption on the pyrite surface, preventing desorption. Therefore, it can effectively inhibit pyrite while reducing lime usage, thus avoiding excessive increases in the pulp pH. This not only improves the concentrate grade but also enhances the recovery rate of associated elements, achieving a win-win situation for both economic and environmental benefits. Simultaneously, this will promote the innovative development of ore processing technology and make a positive contribution to the sustainable utilization of mineral resources and environmental protection. Attached Figure Description

[0027] Figure 1 This is a schematic flowchart of the application method of an environmentally friendly pyrite inhibitor provided in Example 1. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0030] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] A method for preparing an environmentally friendly pyrite inhibitor includes the following steps:

[0032] S1. Add 2-methyl-3-mercaptofuran and cobalt(III) acetate sequentially to an acetic acid solution;

[0033] S2. The material from step S1 is heated to reflux and then reacted for 4 to 10 days. After the reaction is completed, the material is filtered while hot and the filter cake is collected. The filter cake is washed with dilute acetic acid 2 to 3 times and the filtrate is collected. The filtrate is then distilled under reduced pressure to obtain product A. The heating temperature is 130 to 150°C.

[0034] S3. Add the product A into the high-pressure reactor, purge the air in the system with nitrogen (repeat 8 to 10 times), then slowly purge the nitrogen in the system under negative pressure, and then slowly introduce hydrogen until the pressure in the reactor reaches 8 to 10 MPa, then stop introducing hydrogen.

[0035] S4. After raising the temperature inside the reactor to a predetermined temperature, maintain the temperature at a constant level within the predetermined temperature range for a second predetermined time to obtain an environmentally friendly pyrite inhibitor.

[0036] With this setup, functional groups are introduced through a series of derivatization methods to modify 2-methyl-3-mercaptofuran and optimize its structure, thereby preparing an environmentally friendly pyrite inhibitor with a cyclic structure containing both hydrophilic and solidophilic groups. This inhibitor can be used for the flotation separation of sulfide ores such as high-sulfur gold-bearing ores and high-sulfur polymetallic ores.

[0037] Specifically, in some embodiments of the present invention, in step S1, the mass concentration of the acetic acid solution is 20-30%; the mass ratio of 2-methyl-3-mercaptofuran, acetic acid solution, and cobalt(III) acetate is 20-30:400-500:1.

[0038] With this setup, the addition of cobalt(III) acetate acts as a catalyst in the modification of 2-methyl-3-mercaptofuran.

[0039] Specifically, in some embodiments of the present invention, in step S3, the high-pressure reactor is equipped with a sponge nickel mesh.

[0040] This setup allows nickel to act as a catalyst during the modification of 2-methyl-3-mercaptofuran by adding it to the high-pressure reactor.

[0041] Specifically, in some embodiments of the present invention, in step S4, the predetermined temperature is 120-150°C; and the second predetermined time is 4-8 hours.

[0042] This invention provides an application method for an environmentally friendly pyrite inhibitor, comprising the following steps:

[0043] Sa, the target ore, lime, and the environmentally friendly pyrite inhibitor are mixed and ground to a predetermined particle size, and then a slurry of predetermined concentration is prepared; the target ore includes sulfide ores such as high-sulfur gold ore and high-sulfur polymetallic ore;

[0044] Sb, Add butyl xanthate and butyl ammonium black powder to the slurry and stir for 2-5 minutes;

[0045] Sc, then add 20g / t of No. 2 oil and stir for 2-5 minutes;

[0046] Sd, and finally flotation for 4-6 minutes to obtain concentrate and tailings.

[0047] Specifically, in some embodiments of the present invention, in step Sa, the dosage of lime is 500–1000 g / t; the dosage of the environmentally friendly pyrite inhibitor is 200–500 g / t. In step Sb, the dosage of butyl xanthate is 60–150 g / t; the dosage of butylammonium black powder is 10–50 g / t. In step Sc, the dosage of No. 2 oil is 20–50 g / t.

[0048] This setup, using a specially formulated environmentally friendly pyrite inhibitor for the flotation of sulfide ores such as high-sulfur gold-bearing ores and high-sulfur polymetallic ores, allows the inhibitor to act on the active sites on the pyrite mineral surface. The lone pairs of electrons in the ring structure enhance the adsorption of pyrite, preventing desorption. Therefore, it effectively inhibits pyrite while reducing lime usage, thus avoiding excessive increases in pulp pH. This not only improves concentrate grade but also enhances the recovery rate of associated elements, achieving a win-win situation for both economic and environmental benefits. Simultaneously, this will promote innovative development in ore processing technology, making a positive contribution to the sustainable utilization of mineral resources and environmental protection.

[0049] The following describes the working principle of the preparation and application method of the environmentally friendly pyrite inhibitor provided by the present invention:

[0050] Example 1

[0051] This embodiment provides a method for preparing and applying an environmentally friendly pyrite inhibitor, including the following steps:

[0052] S1. Add 1000g of 2-methyl-3-mercaptofuran and 50g of cobalt(III) acetate sequentially to 20000ml of acetic acid solution (acetic acid and water volume ratio of 1:4);

[0053] S2. The material from step S1 is heated to reflux and reacted for 7 days. After the reaction, it is filtered while hot and the filter cake is collected. The filter cake is washed three times with dilute acetic acid and the filtrate is collected. The filtrate is then distilled under reduced pressure to obtain product A.

[0054] S3. Take 100g of the product A and put it into a high-pressure reactor with a built-in nickel sponge mesh. Use nitrogen to purge the air in the system (repeat 8 times), then slowly purge the nitrogen in the system under negative pressure, and then slowly introduce hydrogen until the pressure of the reactor reaches 10MPa. Close the hydrogen valve and stop introducing hydrogen.

[0055] S5. The temperature inside the reactor is gradually increased to 130°C, and then the temperature inside the system is kept stable at around 130°C for 4 hours to obtain an environmentally friendly pyrite inhibitor.

[0056] This embodiment also provides an application method for the environmentally friendly pyrite inhibitor prepared according to the above method, such as... Figure 1 As shown, it includes the following steps:

[0057] This embodiment takes a high-sulfur copper-molybdenum ore as the research object. The ore has a copper grade of 0.52%, a molybdenum grade of 0.024%, an iron grade of 5.26%, a sulfur grade of 1.63%, a gold grade of 0.3 g / t, and a silver grade of 30 g / t. The mineral composition and content of the ore are shown in Table 1.

[0058] Table 1 Results of mineral composition and content analysis of ore

[0059]

[0060] Sa, high-sulfur copper-molybdenum ore, water, lime, and the environmentally friendly pyrite inhibitor are mixed and ground until the content of particles with a particle size of -0.074mm is 70%, and a slurry with a concentration of 28% is prepared.

[0061] The high-sulfur copper-molybdenum ore and water are of equal quality, the dosage of lime is 500 g / t, and the dosage of the environmentally friendly pyrite inhibitor is 200 g / t.

[0062] Sb, Add 80 g / t of butyl xanthate and 20 g / t of butyl ammonium black powder to the slurry, and stir for 2 min;

[0063] Sc, then add 20g / t of #2 oil and stir for 2 minutes;

[0064] Sd, and finally flotation for 5 minutes to obtain concentrate and tailings.

[0065] Examples 2-3

[0066] Examples 2 and 3 respectively provide a method for preparing and applying an environmentally friendly pyrite inhibitor. The difference between these methods and Example 1 lies in the content of the environmentally friendly pyrite inhibitor used. In Example 2, the amount of pyrite inhibitor used is 150 g / t; in Example 3, the amount is 100 g / t. The remaining steps and parameters are the same as in Example 1 and will not be repeated here.

[0067] Comparative Example 1

[0068] Comparative Example 1 provides a method for suppressing pyrite during flotation separation. The difference from Example 1 is that no environmentally friendly pyrite inhibitor was added in step Sa. All other steps and parameters are the same as in Example 1 and will not be repeated here.

[0069] Comparative Example 2

[0070] Comparative Example 2 provides a method for suppressing pyrite during flotation separation. Compared with Example 1, the difference is that no environmentally friendly pyrite inhibitor was added in step Sa, and the amount of lime added was 5000 g / t (using lime as both a pulp conditioner and a pyrite inhibitor). The remaining steps and parameters are the same as in Example 1 and will not be repeated here.

[0071] Comparative Example 3

[0072] Comparative Example 3 provides a method for suppressing pyrite during flotation separation. Compared with Example 1, the difference is that no environmentally friendly pyrite inhibitor was added in step Sa, and the amount of lime added was 3000 g / t (using lime as both a pulp conditioner and a pyrite inhibitor). The remaining steps and parameters are the same as in Example 1 and will not be repeated here.

[0073] Table 2 shows the test results of Examples 1-3 and Comparative Examples 1-3.

[0074]

[0075] The experimental results of Examples 1-3 and Comparative Examples 1-3 are shown in Table 2. It can be seen that the pyrite inhibitor provided by this invention was used in Examples 1-3, which significantly reduced the concentrate yield and significantly improved the grades of valuable elements copper, molybdenum, gold, and silver in the concentrate product, but the recovery rate of valuable elements was not affected. However, the experimental results of Comparative Examples 1-3 show that although increasing the amount of lime can significantly reduce the concentrate grade, the recovery rates of molybdenum, gold, and silver in the concentrate all decreased to varying degrees with the increase of lime dosage. Furthermore, the pH value was very high throughout the process.

[0076] In summary, this invention provides a method for preparing an environmentally friendly pyrite inhibitor. The method involves reacting 2-methyl-3-mercaptofuran and cobalt(III) acetate in an acetic acid solution by heating to reflux, filtering, washing the collected filter cake with dilute acetic acid, distilling the resulting filtrate under reduced pressure, and finally reacting the product in a high-pressure reactor under specific temperature, atmosphere, and pressure to obtain the environmentally friendly pyrite inhibitor. This series of derivatization methods modifies 2-methyl-3-mercaptofuran, introducing functional groups and optimizing its structure, thereby preparing an environmentally friendly pyrite inhibitor with a cyclic structure containing both hydrophilic and solid-philic groups, which can be used for the effective flotation separation of pyrite. Furthermore, when using a specially formulated environmentally friendly pyrite depressant for the flotation of sulfide ores such as high-sulfur gold-bearing ores and high-sulfur polymetallic ores, this environmentally friendly pyrite depressant, with its oxygen-containing cyclic molecular structure, acts on the active sites on the pyrite mineral surface. The lone pair electrons of the cyclic structure enhance the adsorption on the pyrite surface, preventing desorption. Therefore, it can effectively suppress pyrite while reducing lime usage, thus avoiding excessive increases in pulp pH. This not only improves concentrate grade but also enhances the recovery rate of associated elements, achieving a win-win situation for both economic and environmental benefits. Simultaneously, this will promote innovative development in ore processing technology, making a positive contribution to the sustainable utilization of mineral resources and environmental protection.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an environmentally friendly pyrite inhibitor, characterized in that, Includes the following steps: S1. Add 2-methyl-3-mercaptofuran and cobalt(III) acetate sequentially to an acetic acid solution; S2. The material from step S1 is heated to reflux and then reacted for a first predetermined time. After the reaction is completed, it is filtered while hot and the filter cake is collected. The filter cake is washed repeatedly with dilute acetic acid and the filtrate is collected. The filtrate is then distilled under reduced pressure to obtain product A. S3. Add the product A into the high-pressure reactor, purge the air in the system with nitrogen, slowly purge the nitrogen in the system under negative pressure, and then slowly introduce hydrogen until the pressure in the reactor reaches 8-10 MPa, then stop introducing hydrogen. S4. After raising the temperature inside the reactor to a predetermined temperature, maintain the temperature within the predetermined temperature range and react for a second predetermined time to obtain an environmentally friendly pyrite inhibitor.

2. The method for preparing the environmentally friendly pyrite inhibitor according to claim 1, characterized in that: In step S1, the mass concentration of the acetic acid solution is 20-30%.

3. The method for preparing the environmentally friendly pyrite inhibitor according to claim 2, characterized in that: In step S1, the mass ratio of 2-methyl-3-mercaptofuran, acetic acid solution, and cobalt(III) acetate is 20-30:400-500:

1.

4. The method for preparing the environmentally friendly pyrite inhibitor according to claim 1, characterized in that: In step S2, the heating temperature is 130-150°C; the first predetermined reaction time is 4-10 days; and the washing is repeated 2-3 times.

5. The method for preparing the environmentally friendly pyrite inhibitor according to claim 1, characterized in that: In step S3, the high-pressure reactor is equipped with a sponge nickel mesh.

6. The method for preparing the environmentally friendly pyrite inhibitor according to claim 1, characterized in that: In step S4, the predetermined temperature is 120-150°C; the second predetermined time is 4-8 hours.

7. A method for applying the environmentally friendly pyrite inhibitor prepared by the preparation method according to any one of claims 1 to 6, characterized in that, Includes the following steps: Sa, the target ore, lime, and the environmentally friendly pyrite inhibitor are mixed and ground to a predetermined particle size, and then a slurry of predetermined concentration is prepared. Sb, Add butyl xanthate and butyl ammonium black powder to the slurry and stir for 2-5 minutes; Sc, then add 20g / t of No. 2 oil and stir for 2-5 minutes; Sd, and finally flotation for 4-6 minutes to obtain concentrate and tailings.

8. The application method of the environmentally friendly pyrite inhibitor according to claim 7, characterized in that: In step Sa, the dosage of lime is 500-1000 g / t; the dosage of the environmentally friendly pyrite inhibitor is 200-500 g / t.

9. The application method of the environmentally friendly pyrite inhibitor according to claim 7, characterized in that: In step Sb, the dosage of butyl xanthate is 60-150 g / t; the dosage of butylammonium black powder is 10-50 g / t.

10. The application method of the environmentally friendly pyrite inhibitor according to claim 7, characterized in that: In step Sc, the dosage of oil #2 is 20-50 g / t.

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