Preparation method and application of a copper-molybdenum separation inhibitor

Abstract

The application discloses a copper-molybdenum separation inhibitor and a preparation method and application thereof, the inhibitor is a graft copolymer DG-1 obtained by grafting chitosan and sodium mercaptoacetate, the product enhances the selectivity of mercapto group to copper ions, and the adsorption effect on copper ions is enhanced, and the effect on molybdenite is not affected; secondly, the carboxyl groups of the graft product point to the ore pulp and have more active sites, so that the solubility and stability of single chitosan or sodium mercaptoacetate are enhanced; thirdly, the copolymer is relatively simple to prepare, easy to realize, and the economic cost of inhibiting chalcopyrite is effectively reduced. The application separates copper and molybdenum by using the inhibitor, is environment-friendly, has a relatively small dosage, and has a simple and efficient process.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying an inhibitor for copper-molybdenum separation, belonging to the field of mineral processing flotation reagent technology. Background Technology

[0002] The effective separation of molybdenite and chalcopyrite in polymetallic sulfide deposits has always been a challenge. Flotation, as the primary beneficiation process, relies heavily on the development of reagents that significantly impact copper-molybdenum separation efficiency. Because molybdenite has better natural floatability than chalcopyrite, the industrial practice currently often employs copper-suppressing and molybdenum-floating methods for copper-molybdenum separation. However, commonly used chalcopyrite depressants often suffer from problems such as high dosage, high cost, and environmental pollution, leading to decreasing economic benefits. Therefore, developing new, efficient, and environmentally friendly chalcopyrite depressants is crucial.

[0003] Sodium mercaptoacetate (SGA) is a common chalcopyrite inhibitor used in copper-molybdenum separation, but it has several drawbacks: First, SGA exhibits complexation activity with both copper and molybdenum, resulting in poor selectivity. Second, SGA requires strong acid conditions to effectively complex copper ions, which often corrodes experimental equipment and generates organic waste that pollutes the environment. Third, the reaction conditions for SGA are demanding and easily affected by pH and temperature, requiring precise control. Fourth, SGA is an organic sulfur compound, and the sulfur elements or polysulfides generated during its use and disposal can cause environmental pollution. Fifth, SGA is relatively expensive, with an average price of 4 yuan / g. The main mechanisms by which SGA inhibits copper formation are the thiol and carboxyl groups. The carboxyl (-COOH) group is hydrophilic; when the thiol (-SH) group adsorbs onto the chalcopyrite surface, the carboxyl (-COOH) group points towards the slurry solution, thus inhibiting chalcopyrite formation. Chitosan, a natural, biodegradable, and non-toxic polysaccharide, is widely used in biomedicine, wastewater treatment, papermaking, and textiles, and also has applications in copper-molybdenum separation. In copper-molybdenum separation, chitosan offers several advantages: firstly, it exhibits good selectivity for copper ions but weak adsorption capacity for molybdenum ions; secondly, derived from the shells of crustaceans, it possesses good biocompatibility and biodegradability, resulting in minimal environmental impact; and thirdly, chitosan is a low-cost and readily available renewable resource. However, some challenges remain in the industrial production of chitosan, primarily its limited adsorption capacity and poor performance at high copper ion concentrations. Summary of the Invention

[0004] To address the aforementioned problems, one objective of this invention is to provide a novel and highly efficient copper-molybdenum separation inhibitor, DG-1, primarily for the flotation separation of mixed copper-molybdenum concentrates, thus resolving a series of issues encountered when using sodium mercaptoacetate as a chalcopyrite inhibitor.

[0005] The inhibitor of this invention is a graft copolymer DG-1 obtained by grafting chitosan with sodium thioglycolate. This copolymer has the following characteristics: First, the product enhances the selectivity of the thiol group for copper ions, strengthening the adsorption effect of copper ions, while remaining unaffected by molybdenite; Second, the carboxyl (-COOH) groups of the grafted product point towards the slurry and possess more active sites, thereby enhancing the solubility and stability of chitosan or sodium thioglycolate alone; Third, the preparation of this copolymer is relatively simple and easy to achieve, and effectively reduces the economic cost of inhibiting chalcopyrite. The specific reaction molecular formula is:

[0006] The second objective of this invention is to provide a method for preparing the copper-molybdenum separation inhibitor, which has a relatively simple and easy-to-implement preparation process. The specific steps are as follows: (1) First, a sodium thioacetate solution with a volume ratio of 3:25 to 4:25 was mixed with a sodium hydroxide solution, heated and stirred for 4 hours to obtain a pre-reaction mixture; (3) Then add 1.5g~2g of chitosan to the pre-reaction mixture and stir at room temperature for 12h; (4) After the reaction is complete, add 50-60 mL of anhydrous ethanol to the reactants and then collect the precipitate by centrifugation; (5) After filtering the precipitate, wash it repeatedly with anhydrous ethanol and deionized water until the pH of the washing solution is neutral to obtain the modified material. (6) Finally, the modified material is heated to -45°C. o C~-50 o Freeze-dry at C for 48 hours to obtain the final product, inhibitor DG-1.

[0007] The third objective of this invention is to apply the inhibitor for copper-molybdenum separation in the process of copper-molybdenum separation. The specific steps are as follows: (1) Regrinding of copper-molybdenum mixed concentrate: The copper-molybdenum mixed concentrate is regrinded to a fineness of -0.038 mm, accounting for 85%~90%, the slurry concentration is adjusted to 35%~40%, and the slurry is adjusted to pH=12; (2) Copper-molybdenum separation roughing: Add inhibitor DG-1, collector kerosene and frother methyl isobutyl methanol to the slurry obtained in step (1) in sequence, and carry out one copper-molybdenum separation roughing operation to obtain separation roughing concentrate and separation roughing tailings; (3) Copper-molybdenum separation and beneficiation: Add inhibitor DG-1 to the rough concentrate obtained in step (2) and perform four copper-molybdenum separation and beneficiation operations. The beneficiation operation I yields beneficiation I concentrate and beneficiation I middlings. Add inhibitor DG-1 and collector kerosene to beneficiation I concentrate and perform beneficiation II operation to obtain beneficiation II concentrate and beneficiation II middlings. The beneficiation I middlings are returned to one roughing operation. Add inhibitor DG-1 to beneficiation II concentrate and perform beneficiation III operation to obtain beneficiation III concentrate and beneficiation III middlings. The beneficiation II middlings are returned to the beneficiation I operation. Add inhibitor DG-1 and collector kerosene to beneficiation III concentrate and perform beneficiation IV operation to obtain molybdenum concentrate and beneficiation IV middlings. Beneficiation IV is returned to one beneficiation III operation to form a closed loop. (4) Copper-molybdenum separation and scavenging: Add inhibitor DG-1, collector kerosene and frother methyl isobutyl methanol to the roughing tailings obtained in step (1) in sequence to carry out one scavenging operation. The middlings from the scavenging operation are returned to the roughing operation to form a closed loop and obtain copper concentrate.

[0008] In step (2), the dosages of inhibitor DG-1, collector kerosene, and foaming agent methyl isobutyl methanol are 2000~2500g / t, 500~600g / t, and 60~72g / t, respectively.

[0009] In step (3), the dosage of inhibitor DG-1 in the selected operation I is 400~440 g / t, the dosage of inhibitor DG-1 and collector kerosene in the selected operation II is 200~220 g / t and 80~100 g / t, the dosage of inhibitor DG-1 in the selected operation III is 100~110 g / t, and the dosage of inhibitor DG-1 and collector kerosene in the selected operation IV is 50~55 g / t and 45~50 g / t.

[0010] In step (4), the dosages of inhibitor DG-1, collector kerosene, and foaming agent methyl isobutyl methanol are 200~220g / t, 100~150g / t, and 24~30g / t, respectively.

[0011] The beneficial effects of this invention are: 1. The chalcopyrite inhibitor prepared by the present invention can effectively inhibit chalcopyrite, causing molybdenite in the copper-molybdenum mixed concentrate to float out with the foam.

[0012] 2. The chalcopyrite inhibitor prepared by this invention enhances the selectivity of thiol groups for copper ions, thereby strengthening the adsorption effect of copper ions, while remaining unaffected by molybdenite; the carboxyl (-COOH) groups of the grafted product of this invention point towards the slurry and have more active sites, thereby enhancing the solubility and stability of single chitosan or sodium thioglycolate; the copolymer is relatively simple to prepare, easy to implement, and effectively reduces the economic cost of chalcopyrite inhibition.

[0013] 3. The chalcopyrite inhibitor of this invention is environmentally friendly and requires a relatively small dosage.

[0014] 4. This invention uses this inhibitor to separate copper and molybdenum, and the process is simple and efficient. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to illustrate the present invention, but the scope of protection of the present invention is not limited to the content described.

[0017] Example 1: The inhibitor for copper-molybdenum separation in this example is a graft copolymer DG-1 obtained by grafting chitosan with sodium thioglycolate. The molecular reaction formula is as follows:

[0018] The preparation method of the inhibitor in this embodiment is as follows: (1) First, a sodium thioacetate solution with a volume ratio of 4:25 and a sodium hydroxide solution are mixed, heated and stirred for 4 hours to obtain a pre-reaction mixture, wherein sodium thioacetate and sodium hydroxide are respectively prepared as solutions with a mass fraction of 15% and 5%; (3) Then add 2g of chitosan to the pre-reaction mixture and stir at room temperature for 12h; (4) After the reaction is complete, add 50 mL of anhydrous ethanol to the reactants and then collect the precipitate by centrifugation; (5) After filtering the precipitate, wash it repeatedly with anhydrous ethanol and deionized water until the pH of the washing solution is neutral to obtain the modified material. (6) Finally, the modified material is heated to -45°C. o Freeze-dry at C for 48 hours to obtain the final product, inhibitor DG-1.

[0019] The inhibitor prepared in this embodiment was applied to the separation of copper and molybdenum at the Pulang Copper Mine in Yunnan Province. The mineral raw material used was from the Pulang Copper Mine in Yunnan Province, with a Cu content of 0.28%, Mo content of 0.018%, CaO content of 2.26%, MgO content of 1.78%, and an additional 13.68% Al₂O₃ content. Phase analysis revealed that the Cu minerals mainly existed in the form of chalcopyrite and pyrite. The specific separation steps are as follows: (1) Regrinding of copper-molybdenum mixed concentrate: The copper-molybdenum mixed concentrate was regrinded to a fineness of -0.038 mm, accounting for 85% of the total fineness. The pulp concentration was adjusted to 35%, and the pulp was adjusted to pH=12. (2) Copper-molybdenum separation roughing: Add 2000g / t of inhibitor DG-1, 500g / t of collector kerosene and 60g / t of frother methyl isobutyl methanol to the slurry obtained in step (1) in sequence, and carry out one copper-molybdenum separation roughing operation to obtain the separated roughing concentrate and the separated roughing tailings; (3) Copper-molybdenum separation and beneficiation: Add 400g / t of inhibitor DG-1 to the rough concentrate obtained in step (2) and carry out beneficiation operation I. The beneficiation operation I yields beneficiation I concentrate and beneficiation I middlings. The beneficiation I middlings are returned to roughing operation once. Add 200g / t of inhibitor DG-1 and 80g / t of collector kerosene to the beneficiation I concentrate and carry out beneficiation operation II to obtain beneficiation II concentrate and beneficiation II middlings. The beneficiation II middlings are returned to beneficiation operation I once. Add 100g / t of inhibitor DG-1 to the beneficiation II concentrate and carry out beneficiation operation III to obtain beneficiation III concentrate and beneficiation III middlings. The beneficiation III middlings are returned to beneficiation operation II. Add 50g / t of inhibitor DG-1 and 45g / t of collector kerosene to the beneficiation III concentrate and carry out beneficiation operation IV to obtain molybdenum concentrate and beneficiation IV middlings. The beneficiation IV middlings are returned to beneficiation operation III once to form a closed loop. (4) Copper-molybdenum separation and scavenging: Add 200g / t of inhibitor DG-1, 100g / t of collector kerosene, and 24g / t of frother methyl isobutyl methanol to the tailings obtained in step (1) in sequence for one scavenging operation. The middlings from the scavenging operation are returned to the roughing operation to form a closed loop and obtain copper concentrate.

[0020] The molybdenum concentrate obtained in this embodiment contains 46.89% Mo and 0.27% Cu, with a molybdenum recovery rate of 87.62%; the copper concentrate contains 0.32% Mo and 19.68% Cu, with a copper recovery rate of 89.58%.

[0021] Example 2: The preparation method of the inhibitor in this example is the same as that of the raw ore source as in Example 1, except that the volume ratio of sodium thioacetate solution to sodium hydroxide solution is 3:25, and the sodium thioacetate and sodium hydroxide are prepared into solutions with a mass fraction of 10% and 4%, respectively. The amount of chitosan used is 1.5g, 60mL of anhydrous ethanol is added, and the freeze-drying temperature is -50°C. o C. The specific separation steps are as follows: (1) Regrinding of copper-molybdenum mixed concentrate: The copper-molybdenum mixed concentrate was regrinded to a fineness of -0.038 mm, accounting for 90% of the total fineness. The pulp concentration was adjusted to 40%, and the pulp was adjusted to pH=12. (2) Copper-molybdenum separation roughing: Add inhibitor DG-1 2500g / t, collector kerosene 600g / t and frother 72g / t to the slurry obtained in step (1) in sequence, and carry out one copper-molybdenum separation roughing operation to obtain separation roughing concentrate and separation roughing tailings; (3) Copper-molybdenum separation and beneficiation: Add inhibitor DG-1 440g / t to the rough concentrate obtained in step (2) and carry out beneficiation operation I. The beneficiation operation I yields beneficiation I concentrate and beneficiation I middlings. The beneficiation I middlings are returned to roughing operation. Add inhibitor DG-1 220g / t and collector kerosene 100g / t to the beneficiation I concentrate and carry out beneficiation operation II to obtain beneficiation II concentrate and beneficiation II middlings. The beneficiation II middlings are returned to beneficiation operation I. Add inhibitor DG-1 110g / t to the beneficiation II concentrate and carry out beneficiation operation III to obtain beneficiation III concentrate and beneficiation III middlings. The beneficiation III middlings are returned to beneficiation operation II. Add inhibitor DG-1 55g / t and collector kerosene 50g / t to the beneficiation III concentrate and carry out beneficiation operation IV to obtain molybdenum concentrate and beneficiation IV middlings. The beneficiation IV middlings are returned to beneficiation operation III to form a closed loop. (4) Copper-molybdenum separation and scavenging: Add 220g / t of inhibitor DG-1, 150g / t of collector kerosene, and 30g / t of frother methyl isobutyl methanol to the roughing tailings obtained in step (1) in sequence for one scavenging operation. The middlings from the scavenging operation are returned to the roughing operation to form a closed loop and obtain copper concentrate.

[0022] The molybdenum concentrate obtained in this embodiment contains 46.24% Mo and 0.41% Cu, with a molybdenum recovery rate of 86.94%; the copper concentrate contains 0.36% Mo and 19.48% Cu, with a copper recovery rate of 89.42%.

[0023] Example 3: The preparation method of the inhibitor in this example is the same as that in Example 1, except that the volume ratio of sodium thioacetate solution to sodium hydroxide solution is 7:50, sodium thioacetate and sodium hydroxide are prepared into solutions with a mass fraction of 12% and 4.5% respectively, the amount of chitosan is 1.75g, and the mineral raw material used is a copper-molybdenum mixed concentrate with a Cu content of 22.74% and a Mo content of 1.68%, and also contains gangue minerals such as quartz and feldspar.

[0024] The specific separation steps are as follows: (1) Regrinding of copper-molybdenum mixed concentrate: The copper-molybdenum mixed concentrate was regrinded to a fineness of -0.038 mm, accounting for 85% of the total fineness. The pulp concentration was adjusted to 40%, and the pulp was adjusted to pH=12. (2) Copper-molybdenum separation roughing: Add inhibitor DG-1 2300g / t, collector kerosene 550g / t and frother 66g / t to the slurry obtained in step (1) in sequence, and carry out one copper-molybdenum separation roughing operation to obtain separation roughing concentrate and separation roughing tailings; (3) Copper-molybdenum separation and beneficiation: Add inhibitor DG-1 420g / t to the rough concentrate obtained in step (2) and carry out beneficiation operation I. The beneficiation operation I yields beneficiation I concentrate and beneficiation I middlings. The beneficiation I middlings are returned to roughing operation. Add inhibitor DG-1 210g / t and collector kerosene 90g / t to the beneficiation I concentrate and carry out beneficiation operation II to obtain beneficiation II concentrate and beneficiation II middlings. The beneficiation II middlings are returned to beneficiation operation I. Add inhibitor DG-1 105g / t to the beneficiation II concentrate and carry out beneficiation operation III to obtain beneficiation III concentrate and beneficiation III middlings. The beneficiation III middlings are returned to beneficiation operation II. Add inhibitor DG-1 53g / t and collector kerosene 45g / t to the beneficiation III concentrate and carry out beneficiation operation IV to obtain molybdenum concentrate and beneficiation IV middlings. The beneficiation IV middlings are returned to beneficiation operation III to form a closed loop. (4) Copper-molybdenum separation and scavenging: Add 210g / t of inhibitor DG-1, 125g / t of collector kerosene, and 27g / t of frother methyl isobutyl methanol to the roughing tailings obtained in step (1) in sequence for one scavenging operation. The middlings from the scavenging operation are returned to the roughing operation to form a closed loop and obtain copper concentrate.

[0025] The molybdenum concentrate obtained in this embodiment contains 50.36% Mo and 0.42% Cu, with a molybdenum recovery rate of 82.16%. The copper concentrate contains 0.28% Mo and 25.16% Cu, with a copper recovery rate of 86.92%.

Claims

1. A method for preparing an inhibitor for copper-molybdenum separation, characterized in that, The inhibitor is a graft copolymer DG-1 obtained by grafting chitosan with sodium thioglycolate. The specific steps for preparing the copper-molybdenum separation inhibitor are as follows: (1) First, a sodium thioacetate solution with a volume ratio of 3:25 to 4:25 was mixed with a sodium hydroxide solution, heated and stirred for 4 hours to obtain a pre-reaction mixture; (2) Then add 1.5g~2g of chitosan to the pre-reaction mixture and stir at room temperature for 12h; (3) After the reaction is complete, add 50-60 mL of anhydrous ethanol to the reactants and then collect the precipitate by centrifugation; (4) After filtering the precipitate, wash it repeatedly with anhydrous ethanol and deionized water until the pH of the washing solution is neutral to obtain the modified material. (5) Finally, the modified material is heated to -45°C. o C~-50 o Freeze-dry at C for 48 hours to obtain the final product, inhibitor DG-1. Its molecular reaction formula is as follows: 。 2. The method for preparing the inhibitor for copper-molybdenum separation according to claim 1, characterized in that: In step (1), sodium thioglycolate and sodium hydroxide are prepared into solutions with a mass fraction of 10%~15% and 4%~5%, respectively.

3. The inhibitor prepared by the method for preparing the inhibitor for copper-molybdenum separation according to any one of claims 1 to 2 is used in copper-molybdenum separation, characterized in that, The specific steps are as follows: (1) Regrinding of copper-molybdenum mixed concentrate: The copper-molybdenum mixed concentrate is regrinded to a fineness of -0.038 mm, accounting for 85%~90%, the slurry concentration is adjusted to 35%~40%, and the slurry is adjusted to pH=12; (2) Copper-molybdenum separation roughing: Add inhibitor DG-1, collector kerosene and frother methyl isobutyl methanol to the slurry obtained in step (1) in sequence, and carry out one copper-molybdenum separation roughing operation to obtain separation roughing concentrate and separation roughing tailings; (3) Copper-molybdenum separation and beneficiation: Add inhibitor DG-1 to the rough concentrate obtained in step (2) and perform four copper-molybdenum separation and beneficiation operations. The beneficiation operation I yields beneficiation I concentrate and beneficiation I middlings. The beneficiation I middlings are returned to one roughing operation. Add inhibitor DG-1 and collector kerosene to the beneficiation I concentrate and perform beneficiation II operation to obtain beneficiation II concentrate and beneficiation II middlings. The beneficiation II middlings are returned to one beneficiation I operation. Add inhibitor DG-1 to the beneficiation II concentrate and perform beneficiation III operation to obtain beneficiation III concentrate and beneficiation III middlings. The beneficiation III middlings are returned to the beneficiation II operation. Add inhibitor DG-1 and collector kerosene to the beneficiation III concentrate and perform beneficiation IV operation to obtain molybdenum concentrate and beneficiation IV middlings. The beneficiation IV middlings are returned to one beneficiation III operation to form a closed loop. (4) Copper-molybdenum separation and scavenging: Add inhibitor DG-1, collector kerosene and frother methyl isobutyl methanol to the roughing tailings obtained in step (1) in sequence to carry out one scavenging operation. The middlings from the scavenging operation are returned to the roughing operation to form a closed loop and obtain copper concentrate.

4. The application of the inhibitor for copper-molybdenum separation according to claim 3 in copper-molybdenum separation, characterized in that: In step (2), the dosages of inhibitor DG-1, collector kerosene, and foaming agent methyl isobutyl methanol are 2000~2500g / t, 500~600g / t, and 60~72g / t, respectively.

5. The application of the inhibitor for copper-molybdenum separation according to claim 3 in copper-molybdenum separation, characterized in that: In step (3), the dosage of inhibitor DG-1 in the selected operation I is 400~440 g / t, the dosage of inhibitor DG-1 and collector kerosene in the selected operation II is 200~220 g / t and 80~100 g / t, the dosage of inhibitor DG-1 in the selected operation III is 100~110 g / t, and the dosage of inhibitor DG-1 and collector kerosene in the selected operation IV is 50~55 g / t and 45~50 g / t.

6. The application of the inhibitor for copper-molybdenum separation according to claim 3 in copper-molybdenum separation, characterized in that: In step (4), the dosages of inhibitor DG-1, collector kerosene, and foaming agent methyl isobutyl methanol are 200~220g / t, 100~150g / t, and 24~30g / t, respectively.

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