Sulfide ore collecting agent based on thiophene-amide-sodium phosphate salt and preparation method and application thereof

Abstract

The invention provides a sulfide ore collecting agent based on thiophene-amide-sodium phosphate and a preparation method and application of the sulfide ore collecting agent, and belongs to the field of chemical synthesis and mineral processing. A sodium phosphate group at the tail end of the collecting agent endows molecules with excellent water solubility, and efficient dispersion and convenient adding of the agent in ore pulp are achieved; meanwhile, the hydrophilic group is preferentially anchored on the surface of the mineral through electrostatic interaction and cooperates with the directional adsorption of the rigid thiophene skeleton and the specific coordination of the amide group on the copper and zinc ions to form a unique'electrostatic pre-anchoring-plane adsorption-coordination locking 'multi-step synergistic effect mechanism. The mechanism not only strengthens the collecting capacity of chalcopyrite and sphalerite, but also reduces non-selective adsorption of non-target minerals such as pyrite from the molecular level through electrical repulsion and steric hindrance effects, so that efficient selective separation of copper and zinc minerals is realized under the condition of not depending on a high-alkali condition and a large number of inhibitors.

Description

Technical Field

[0001] This invention belongs to the fields of chemical synthesis and mineral processing, and particularly relates to a method for preparing a sulfide mineral collector based on thiophene-amide-sodium phosphate and a method for collecting chalcopyrite and sphalerite using the collector. Background Technology

[0002] In the flotation separation of copper-zinc sulfide ores, improving separation efficiency and selectivity has long been a core challenge. Due to the similarity of surface properties and complex symbiotic relationship between chalcopyrite and sphalerite, traditional processes relying on thiocyanates and dithiocyanates often face the dilemma of insufficient selectivity. While these collectors have strong collecting power for copper minerals, their selective differentiation ability for sphalerite is limited, and they generally have weak inhibitory effect on pyrite, resulting in severe intermingling of concentrates and poor separation performance.

[0003] To achieve effective separation, existing processes often have to rely on a high-alkalinity environment and use large amounts of inhibitors such as lime, which not only worsens the operating environment and increases costs, but may also inhibit the recovery of precious metals.

[0004] Therefore, there is an urgent need to develop a new type of collector that can achieve efficient and selective separation of copper and zinc under milder conditions and has a natural tendency to inhibit pyrite, for the clean utilization of complex sulfide mineral resources. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a novel sulfide mineral collector based on a specific thiophene derivative and its preparation method. The molecular structure of this collector is sodium 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene-2-propylphosphate, as follows: .

[0006] This invention also provides a method for preparing a sulfide mineral collector based on thiophene-amide-sodium phosphate, comprising the following steps: A1: Synthesize the amide side chain intermediate 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide; A borane-dimethyl sulfide complex was added dropwise to an anhydrous THF solution of monomethyl glutarate, with a molar equivalent ratio of monomethyl glutarate to the borane-dimethyl sulfide complex of 3.33–3.50. After the addition was complete, the mixture was allowed to react at room temperature for 2–8 hours to obtain an alcohol. Subsequently, the obtained alcohol was dissolved in dichloromethane, and triphenylphosphine and N-bromosuccinimide were added sequentially. After the reaction was stirred and completed, 5-bromopentanoic acid was obtained by purification. The molar ratio of monomethyl glutarate, triphenylphosphine, and N-bromosuccinimide was 68:(80–100):(80–100). The obtained 5-bromopentanoic acid was dissolved in anhydrous dichloromethane, and DMF was added as a catalyst. Oxaloyl chloride was slowly added dropwise at 0°C, with a molar equivalent ratio of 5-bromopentanoic acid to oxaloyl chloride of 1:(1~3). After the addition was completed, the mixture was heated to room temperature and stirred for 2-3 hours to obtain unpurified 5-bromopentanoic acid chloride. Under stirring conditions at 0°C, an anhydrous dichloromethane solution of unpurified 5-bromopentanoyl chloride was slowly added dropwise to an anhydrous dichloromethane solution of N-ethylmethylamine and triethylamine; wherein the molar equivalent ratio of 5-bromopentanoyl chloride, N-ethylmethylamine, and triethylamine was 1:(1~1.5):1; after the reaction was completed, the target intermediate 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide was obtained after purification. A2: Introducing the thiophene skeleton via the Negishi coupling reaction; Add 3-bromothiophene and anhydrous THF, then add i-PrMgCl·LiCl solution dropwise, wherein the molar equivalent ratio of 3-bromothiophene to i-PrMgCl·LiCl is 1:(1~1.3); after the addition is complete, stir at -20℃ for 1~6 hours to generate thiophene-3-kilgrimelckel reagent; quickly add ZnCl2 solution to the above Grignard reagent solution and stir for 30 minutes to generate the corresponding zinc reagent solution; The bromine compound 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide prepared in step A1 was dissolved in anhydrous THF at a molar equivalent ratio of (20~25):1. The prepared zinc reagent solution was transferred to a solution containing a catalyst (Pd(dppf)Cl2 dissolved in THF) and the substrate 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide; after the reaction was completed, the solution was purified to obtain 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene. A3: Introducing a propyl phosphate side chain; Under nitrogen protection and at -78°C, n-BuLi was slowly added dropwise to the anhydrous THF solution of the product from step A2; wherein the molar equivalent ratio of 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene to n-BuLi was 1:(1~1.5); after the addition was complete, the mixture was stirred at -78°C for 1 hour to obtain a transition lithium solution. Dissolve 1,3-dibromopropane in a small amount of THF, wherein the molar equivalent ratio of 1,3-dibromopropane to the product of A2 is (3~5):1, and slowly add it dropwise to the above transition lithium solution; after the addition is complete, slowly raise the temperature to room temperature and stir overnight to obtain 3-(3-bromopropyl)thiophene derivative. The obtained 3-(3-bromopropyl)thiophene derivative was mixed with potassium acetate in DMF at a molar ratio of 1:(2.5~5), heated to 80℃ and stirred for 6-8 hours to obtain crude bromopropanol. Unpurified propanol bromopropanol and diisopropylethylamine were dissolved in anhydrous acetonitrile at a molar ratio of 1:(2.5~4), and dibenzyl chlorophosphate was added dropwise, wherein the molar ratio of dibenzyl chlorophosphate to unpurified propanol bromopropanol was (1.5~2):1; after purification, a precursor protected by dibenzyl phosphate was obtained. A4: Removal of protecting groups yields the target salt compound; The precursor obtained in step A3 was dissolved in anhydrous methanol / tetrahydrofuran mixed solvent, and palladium on carbon was added, wherein the mass ratio of palladium on carbon to the precursor obtained in A3 was 1:10; the mixture was stirred vigorously for 6-12 hours at room temperature and atmospheric pressure under hydrogen atmosphere. After the reaction was completed, palladium on carbon was removed by filtration with diatomaceous earth with a particle size range of 400 mesh, and the filtrate was concentrated under reduced pressure to obtain phosphate compounds. The above-mentioned phosphoric acid compounds were dissolved in a methanol / water mixed solvent, and sodium hydroxide aqueous solution was added dropwise under ice bath cooling until the pH reached 7-8. The solution was concentrated to dryness under reduced pressure at low temperature to obtain crude salt; it was then purified by recrystallization using hot isopropanol or an ethanol / acetone mixed solvent. The purified solid was dried in a vacuum drying oven to obtain the final product 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene-2-propyl phosphate sodium.

[0007] This molecule possesses a unique multifunctional integrated structure: the rigid thiophene ring, acting as a hydrophobic framework and directional adsorption group, can specifically interact with the mineral surface through π electrons and provide a stable planar orientation; the attached N-ethyl-N-methylpentanamide side chain, with its amide bond, can form a stable surface chelate by bidentate coordination with the target metal ion through oxygen and nitrogen atoms, while the introduction of ethyl and methyl groups finely tunes the coordination selectivity and hydrophobic properties through steric hindrance; the terminal sodium propyl phosphate endows the molecule with excellent water solubility, while its phosphate anion can preferentially adsorb onto specific sites on the mineral surface in the slurry through electrostatic interaction, achieving electrostatic anchoring, thereby guiding the subsequent coordination and hydrophobic adsorption processes.

[0008] The drug's molecular structure contains thiophene-amide-phosphate molecular fragments, achieving a coherent synergistic mechanism at the molecular level from electrostatic recognition and directional adsorption to enhanced hydrophobicity.

[0009] The mechanism of action of this collector breaks through the single-action mode of traditional agents. The sodium phosphate group not only solves the water solubility problem, but its preferential adsorption behavior also creates a kinetic advantage for the entire molecule to be enriched at the mineral-water interface. Subsequently, the planar conjugated structure of the thiophene ring achieves stable adsorption through van der Waals forces and π-interactions, fixing the spatial orientation of the molecule. Finally, the amide group in the optimal spatial position coordinates efficiently with the metal site on the mineral surface, locking in the entire adsorption process.

[0010] In addition, the stereo shielding effect generated by the alkyl groups in the side chain, and the electrostatic repulsion of the phosphate group on the surface of non-target minerals, together reduce the non-selective adsorption of minerals such as pyrite from both physical and electrical perspectives, thus endowing the molecule with inherent high selectivity.

[0011] At the application level, the excellent water solubility of this reagent simplifies the addition and dispersion process of flotation reagents, and is expected to maintain high efficiency and selectivity over a wider pH range, thus enabling efficient flotation.

[0012] This invention also provides a method for collecting chalcopyrite and sphalerite, using the sulfide mineral collector based on thiophene-amide-sodium phosphate as described in the aforementioned technical solution, specifically including the following steps: S1, mix minerals containing chalcopyrite and sphalerite with water to form a slurry; S2, adjust the pulp pH to 7-14, add the sulfide mineral collector based on thiophene-amide-sodium phosphate, then add kerosene, followed by the frother MIBC; after 2-5 minutes, introduce air and start flotation.

[0013] Furthermore, the total amount of the sulfide mineral collector based on thiophene-amide-sodium phosphate is 0.1~1 kg / t.

[0014] Furthermore, the amount of kerosene used is 50~100 g / t.

[0015] Furthermore, the amount of the foaming agent MIBC is 25~50 g / t.

[0016] Furthermore, during the flotation process, bubbles are skimmed off every 5 to 10 seconds, and water is added every 30 to 40 seconds.

[0017] The beneficial effects of this invention are: 1. The thiophene-amide-sodium phosphate-based sulfide mineral collector of this application solves the common problems of poor water solubility and insufficient selectivity of traditional sulfide mineral collectors through the synergistic molecular structure of "thiophene-amide-sodium phosphate". Its terminal sodium phosphate group endows the molecule with excellent water solubility, enabling efficient dispersion and convenient addition of the reagent in the slurry. Simultaneously, this hydrophilic group preferentially anchors to the mineral surface through electrostatic interactions, synergistically combining the directional adsorption of the rigid thiophene skeleton with the specific coordination of the amide group to copper and zinc ions, forming a unique multi-step synergistic mechanism of "electrostatic pre-anchoring - planar adsorption - coordination locking". This mechanism not only enhances the collecting ability of chalcopyrite and sphalerite, but also reduces the non-selective adsorption of non-target minerals such as pyrite at the molecular level through electrostatic repulsion and steric hindrance effects, thereby achieving efficient and selective separation of copper and zinc minerals without relying on high-alkaline conditions and large amounts of inhibitors.

[0018] 2. The thiophene-amide-sodium phosphate-based sulfide ore collector of this application exhibits significant technological and environmental advantages in practical applications. Its excellent water solubility simplifies the preparation and addition process of flotation reagents, improving operability. Its high selectivity for target minerals and natural inhibition of pyrite effectively reduce the cross-contamination of copper and zinc concentrates, improving product quality and significantly reducing the amount of traditional modifiers such as lime. This not only lowers the overall reagent cost but also allows flotation under neutral and weakly alkaline conditions, providing an alternative solution for the efficient separation of complex, low-grade copper-zinc sulfide ore resources. Attached Figure Description

[0019] Figure 1 This is a photograph of a sulfide mineral collector based on thiophene-amide-sodium phosphate.

[0020] Figure 2 The image shows the 1H NMR spectrum of a sulfide mineral collector based on thiophene-amide-sodium phosphate.

[0021] Figure 3 This refers to the occurrence form of chalcopyrite in the original ore.

[0022] Figure 4 This refers to the form in which sphalerite is found in the original ore.

[0023] Figure 5 This refers to the occurrence form of chalcopyrite in tailings. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] 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.

[0027] To achieve effective separation, existing sphalerite harvesting processes often have to rely on a high-alkalinity environment and use large amounts of depressants such as lime. This not only worsens the operating environment and increases costs, but may also inhibit the recovery of precious metals.

[0028] This application provides a sulfide mineral collector based on thiophene-amide-sodium phosphate, the molecular structure of which is as follows: .

[0029] This application also provides a method for preparing a sulfide mineral collector based on thiophene-amide-sodium phosphate.

[0030] The synthesis process of this sulfide mineral collector based on thiophene-amide-sodium phosphate includes the following steps: A1: Synthetic intermediate 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide for amide side chain: Synthetic route: Monomethyl glutarate → 5-bromopentanoic acid → 5-bromopentanoyl chloride → target amide bromide.

[0031] A borane-dimethyl sulfide complex was slowly added dropwise to an anhydrous THF solution of monomethyl glutarate under stirring in an ice bath at 0°C. The molar equivalent ratio of monomethyl glutarate to the borane-dimethyl sulfide complex was 3.33–3.50. After the addition was complete, the mixture was allowed to react at room temperature for 2 hours. The reaction was monitored by TLC to indicate completion. Excess borane was carefully quenched with methanol, and then the solution was concentrated under reduced pressure. The resulting crude alcohol was dissolved in dichloromethane and cooled in an ice bath. Triphenylphosphine and N-bromosuccinimide were then added sequentially.

[0032] The molar ratio of monomethyl glutarate to triphenylphosphine and N-bromosuccinimide was 68:80~100:80~100. The mixture was heated to room temperature and stirred overnight. After the reaction was complete, the mixture was filtered, and the filtrate was washed successively with water, saturated NaHCO3 solution, and saturated brine. It was dried over anhydrous Na2SO4 and concentrated. Purification was achieved by silica gel column chromatography (petroleum ether / ethyl acetate = 4:1) to obtain a colorless oily substance, 5-bromopentanoic acid.

[0033] The obtained 5-bromopentanoic acid was dissolved in anhydrous dichloromethane, and 2-10 drops of DMF were added as a catalyst. Oxaloyl chloride was slowly added dropwise at 0°C, with a molar ratio of 5-bromopentanoic acid to oxaloyl chloride of 1:1-3. After the addition was complete, the mixture was brought to room temperature and stirred for 2-3 hours until no gas was released. Excess oxaloyl chloride and solvent were removed by vacuum distillation to obtain a pale yellow oily substance, 5-bromopentanoyl chloride, which could be used directly in the next step without further purification.

[0034] A solution of 5-bromopentanoyl chloride (unpurified) in anhydrous dichloromethane was slowly added dropwise to a solution of N-ethylmethylamine and triethylamine in anhydrous dichloromethane under stirring at 0°C; the molar ratio of 5-bromopentanoyl chloride to N-ethylmethylamine and triethylamine was 1:1 to 1.5:1. After the addition was complete, the mixture was brought to room temperature and stirred overnight. After the reaction was complete, the reaction solution was washed successively with 1M HCl solution, saturated NaHCO3 solution, and saturated saline solution, dried over anhydrous Na2SO4, and concentrated.

[0035] The target intermediate, 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide, was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 2:1) as a pale yellow oil.

[0036] A2: Introducing the thiophene skeleton via the Negishi coupling reaction: Synthetic route: 3-bromothiophene + i-PrMgCl·LiCl → 3-thiophene zinc reagent + 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide → 3-substituted thiophene amide.

[0037] Under nitrogen protection, 3-bromothiophene and anhydrous THF were added to a dry reaction flask. The system was cooled to -20°C. i-PrMgCl·LiCl solution was slowly added dropwise, with a molar equivalent ratio of 3-bromothiophene to i-PrMgCl·LiCl of 1:1 to 1.3. The internal temperature was maintained below -10°C. After the addition was complete, the mixture was stirred at -20°C for 1 hour to generate thiophene-3-kilgrimer reagent. ZnCl2 solution was rapidly added to the thiophene-3-kilgrimer reagent solution, and the mixture was stirred for 30 minutes to generate the corresponding zinc reagent solution.

[0038] In a dry reaction flask, the brominated product 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide prepared in A1 and Pd(dppf)Cl2 were dissolved in anhydrous THF at a molar ratio of 20–25:1. The prepared zinc reagent solution was transferred via syringe to a solution containing the catalyst (Pd(dppf)Cl2 dissolved in THF) and the substrate 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide. The mixture was brought to room temperature and stirred overnight under nitrogen protection. After the reaction was complete, saturated NH4Cl solution was added to quench the reaction. The mixture was extracted with ethyl acetate, and the combined organic phases were washed successively with saturated brine, dried over anhydrous Na2SO4, and concentrated.

[0039] Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 1:1) yielded 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene, a yellow oil.

[0040] A3: Introduction of propyl phosphate side chain: Synthesis path: (1) The product of step A2 + n-BuLi → transition lithium.

[0041] (2) Transitional lithium + 1,3-dibromopropane capture → bromopropanol → phosphorylation → benzyl phosphate protected precursor.

[0042] Under nitrogen protection and at -78°C, n-BuLi (a 2.5 M n-BuLi-acetone solution) was slowly added dropwise to an anhydrous THF solution of the product of A2, with a molar ratio of the product of A2 to n-BuLi of 1:1 to 1.5. After the addition was complete, the mixture was stirred at -78°C for 1 hour.

[0043] 1,3-Dibromopropane was dissolved in a small amount of THF, wherein the molar ratio of 1,3-dibromopropane to the product A2 was 3–5:1, and slowly added dropwise to the above transition lithium compound solution. After the addition was complete, the solution was slowly brought to room temperature and stirred overnight. The reaction was quenched with saturated NH4Cl solution. After extraction, washing, drying, and concentration, the product was purified by column chromatography to obtain a bromine-terminated 3-(3-bromopropyl)thiophene derivative.

[0044] The brominated product obtained in the previous step was mixed with potassium acetate in DMF at a molar ratio of 1:2.5-5, and the mixture was heated to 80°C and stirred for 6-8 hours. After cooling, the mixture was diluted with water and extracted with ethyl acetate. The organic phase was washed with saturated brine, dried, and concentrated to obtain bromopropanol, which can be used directly in the next step.

[0045] Bromopropanol and diisopropylethylamine were dissolved in anhydrous acetonitrile at a molar ratio of 1:2.5–4. Dibenzyl chlorophosphate was slowly added dropwise under ice bath cooling, wherein the molar ratio of dibenzyl chlorophosphate to bromopropanol was 1.5–2:1. After the addition was complete, the mixture was brought to room temperature and stirred overnight. The solution was concentrated under reduced pressure and purified by column chromatography (petroleum ether / ethyl acetate gradient elution) to obtain the protected precursor of dibenzyl phosphate.

[0046] A4: Remove the protecting group to generate the target salt compound.

[0047] Synthetic pathway: Dibenzyl phosphate precursor + H2 / Pd / C → Debenzylation + NaOH → Sodium phosphate.

[0048] The precursor obtained in step A3 was dissolved in anhydrous methanol / tetrahydrofuran mixed solvent (1:1, 50 mL). Palladium on carbon (10% Pd / C) was added, with a mass ratio of palladium on carbon to the precursor obtained in A3 of 1:10. The reaction system was connected to a hydrogen balloon and stirred vigorously for 6–12 hours at room temperature and atmospheric pressure under a hydrogen atmosphere. The complete removal of the benzyl group was monitored by TLC.

[0049] After the reaction was completed, palladium on carbon was removed by filtration with diatomaceous earth with a particle size of 400 mesh, and the filtrate was concentrated under reduced pressure to obtain phosphate compounds.

[0050] The above-mentioned phosphoric acid compounds were dissolved in a small amount of methanol / water mixed solvent. Under ice bath cooling, an aqueous sodium hydroxide solution (1.0 M) was added dropwise until the pH reached 7-8. The solution was concentrated to dryness under reduced pressure at low temperature to obtain crude salt. Purification was achieved by recrystallization using hot isopropanol or an ethanol / acetone mixed solvent.

[0051] The purified solid was dried in a vacuum drying oven to obtain the final product as a white oily substance, sodium 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene-2-propyl phosphate.

[0052] This application also provides a method for collecting chalcopyrite and sphalerite, using the aforementioned sulfide mineral collector based on thiophene-amide-sodium phosphate, specifically including the following steps: S1, mix minerals containing chalcopyrite and sphalerite with water to form a slurry; S2, adjust the pulp pH to 7-14, add the sulfide mineral collector based on thiophene-amide-sodium phosphate, then add kerosene, followed by the frother MIBC; after 2-5 minutes, introduce air and start flotation.

[0053] The total amount of sulfide mineral collector based on thiophene-amide-sodium phosphate is 0.1~1 kg / t, the amount of kerosene is 50~100 g / t, and the amount of foaming agent MIBC is 25~50 g / t.

[0054] During the flotation process, skim off the bubbles every 5 to 10 seconds and add water every 30 to 40 seconds, repeating the process.

[0055] The floated copper / zinc concentrates were collected at cumulative flotation times of 1, 3, 6, and 10 minutes, yielding four different copper / zinc concentrates. After filtration, the copper / zinc concentrates were dried in a 60°C oven, weighed, and the total recovery rate was calculated.

[0056] The total recovery rate of copper / zinc concentrate is calculated by dividing the total mass of copper / zinc concentrate by the total mass of minerals containing chalcopyrite and sphalerite.

[0057] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0058] Example 1 Table 1. Mineral composition and relative content of the ore The mineral composition of a certain ore is shown in Table 1. This ore is a skarn-type ore, rich in hedonic pyroxene and garnet group minerals, and associated with various zinc, copper, and lead sulfides and oxide minerals.

[0059] The molecular structure of the sulfide mineral collector based on thiophene-amide-sodium phosphate is as follows: .

[0060] The synthesis process of this sulfide mineral collector based on thiophene-amide-sodium phosphate includes the following steps: A1: Synthetic intermediate 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide for amide side chain: Synthetic route: Monomethyl glutarate → 5-bromopentanoic acid → 5-bromopentanoyl chloride → target amide bromide.

[0061] Under stirring and in an ice bath at 0°C, a borane-dimethyl sulfide complex (10.2 mL, 20.4 mmol) was slowly added dropwise to an anhydrous THF (100 mL) solution of monomethyl glutarate (10.0 g, 68.0 mmol). After the addition was complete, the mixture was allowed to react at room temperature for 2 hours. The reaction was monitored by TLC. Excess borane was carefully quenched with methanol, and then the mixture was concentrated under reduced pressure. The resulting crude alcohol was dissolved in dichloromethane (100 mL) and cooled in an ice bath. Triphenylphosphine (21.4 g, 81.6 mmol) and N-bromosuccinimide (14.5 g, 81.6 mmol) were added sequentially. The mixture was stirred overnight at room temperature. After the reaction was complete, the mixture was filtered, and the filtrate was washed successively with water, saturated NaHCO3 solution, and saturated brine. The filtrate was dried over anhydrous Na2SO4 and concentrated. The solution was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 4:1) to give a colorless oily product, 5-bromopentanoic acid.

[0062] The obtained 5-bromopentanoic acid (approximately 8.0 g, 44.0 mmol) was dissolved in anhydrous dichloromethane (50 mL), and 2 drops of DMF were added as a catalyst. Oxaloyl chloride (5.6 mL, 66.0 mmol) was slowly added dropwise at 0 °C. After the addition was complete, the mixture was brought to room temperature and stirred for 2–3 hours until no gas was released. Excess oxaloyl chloride and solvent were removed by vacuum distillation to obtain a pale yellow oily substance, 5-bromopentanoyl chloride, which could be used directly in the next step without further purification.

[0063] A solution of 5-bromopentanoyl chloride (unpurified, approximately 44.0 mmol) in anhydrous dichloromethane (50 mL) was slowly added dropwise to a solution of N-ethylmethylamine (5.4 g, 92.4 mmol) and triethylamine (12.3 mL, 88.0 mmol) in anhydrous dichloromethane (100 mL) under stirring at 0 °C. After the addition was complete, the mixture was brought to room temperature and stirred overnight. After the reaction was complete, the reaction solution was washed successively with 1 M HCl solution, saturated NaHCO3 solution, and saturated saline solution, dried over anhydrous Na2SO4, and concentrated.

[0064] The target intermediate, 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide, was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 2:1) as a pale yellow oil.

[0065] A2: Introducing the thiophene skeleton via the Negishi coupling reaction: Synthetic route: 3-bromothiophene + i-PrMgCl·LiCl → 3-thiophene zinc reagent + 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide → 3-substituted thiophene amide.

[0066] Under nitrogen protection, 3-bromothiophene (5.0 g, 30.6 mmol) and anhydrous THF (30 mL) were added to a dry reaction flask. The system was cooled to -20 °C. i-PrMgCl·LiCl solution (28.2 mL, 36.7 mmol) was slowly added dropwise, maintaining the internal temperature below -10 °C. After the addition was complete, the mixture was stirred at -20 °C for 1 hour to generate thiophene-3-kigler reagent.

[0067] At -20°C, ZnCl2 solution (1.0 M in THF, 36.7 mL, 36.7 mmol) was rapidly added to the Grignard reagent solution above, and the mixture was stirred for 30 minutes to generate the corresponding zinc reagent solution.

[0068] In a dry reaction flask, 8.8 g (33.7 mmol) of the brominated compound 5-(N-ethyl-N-methylcarbamoyl)pentyl bromide prepared in A1 and 1.12 g (1.53 mmol) of Pd(dppf)Cl2 were dissolved in anhydrous THF (30 mL). The prepared zinc reagent solution was transferred to the solution containing the catalyst and substrate using a syringe. The mixture was brought to room temperature and stirred overnight under nitrogen protection. After the reaction was complete, it was quenched with saturated NH4Cl solution. The mixture was extracted with ethyl acetate, and the combined organic phases were washed successively with saturated brine, dried over anhydrous Na2SO4, and concentrated.

[0069] Purification by silica gel column chromatography (petroleum ether / ethyl acetate = 1:1) yielded 3-[4,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene, a yellow oil.

[0070] A3: Introduction of propyl phosphate side chain: Synthesis path: (1) The product of step A2 + n-BuLi → transition lithium.

[0071] (2) Transition lithium + 1,3-dibromopropane capture → bromopropanol → phosphorylation → benzyl phosphate protected precursor.

[0072] Under nitrogen protection and at -78°C, n-BuLi (24.5 mmol n-BuLi, 9.8 mL acetone, i.e., a 2.5 M n-BuLi-acetone solution system) was slowly added dropwise to an anhydrous THF (60 mL) solution of the product of A2 (6.0 g, 20.4 mmol). After the addition was complete, the mixture was stirred at -78°C for 1 hour.

[0073] 1,3-Dibromopropane (8.3 mL, 81.6 mmol) was dissolved in a small amount of THF and slowly added dropwise to the above transition lithium compound solution. After the addition was complete, the solution was slowly brought to room temperature and stirred overnight. The reaction was quenched with saturated NH4Cl solution. After extraction, washing, drying, and concentration, the solution was purified by column chromatography to obtain a bromine-terminated 3-(3-bromopropyl)thiophene derivative.

[0074] The brominated product obtained in the previous step (approximately 5.0 g, 12.0 mmol) was mixed with potassium acetate (3.5 g, 36.0 mmol) in DMF (50 mL), and the mixture was heated to 80 °C and stirred for 6–8 hours. After cooling, the mixture was diluted with water and extracted with ethyl acetate. The organic phase was washed with saturated brine, dried, and concentrated to obtain bromopropanol, which can be used directly in the next step.

[0075] Unpurified alcohol (bromopropanol) (approximately 4.0 g, 10.9 mmol) and diisopropylethylamine (5.7 mL, 32.7 mmol) were dissolved in anhydrous acetonitrile (40 mL). Dibenzyl chlorophosphate (3.6 mL, 16.4 mmol) was slowly added dropwise under ice bath cooling. After the addition was complete, the mixture was brought to room temperature and stirred overnight. The solution was concentrated under reduced pressure and purified by column chromatography (petroleum ether / ethyl acetate gradient elution) to obtain the protected precursor of dibenzyl phosphate.

[0076] A4: Remove the protecting group to generate the target salt compound.

[0077] Synthetic pathway: Dibenzyl phosphate precursor + H2 / Pd / C → Debenzylation + NaOH → Sodium phosphate.

[0078] The precursor obtained in step A3 (approximately 3.0 g, 5.0 mmol) was dissolved in anhydrous methanol / tetrahydrofuran mixed solvent (1:1, 50 mL). Palladium on carbon (10% Pd / C, 300 mg) was added. The reaction system was connected to a hydrogen balloon and stirred vigorously for 6–12 hours at room temperature and atmospheric pressure under a hydrogen atmosphere. The complete removal of the benzyl group was monitored by TLC.

[0079] After the reaction was completed, palladium on carbon was removed by filtration with diatomaceous earth with a particle size of 400 mesh, and the filtrate was concentrated under reduced pressure to obtain phosphate compounds.

[0080] The above-mentioned phosphoric acid compounds were dissolved in a small amount of methanol / water mixed solvent. Under ice bath cooling, sodium hydroxide aqueous solution (1.0 M) was added dropwise to adjust the pH to 7-8. The solution was concentrated to dryness under reduced pressure at low temperature to obtain crude salt. Purification was achieved by recrystallization using hot isopropanol or an ethanol / acetone mixed solvent.

[0081] The purified solid was dried in a vacuum drying oven to obtain a white oily substance, sodium 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene-2-propyl phosphate, as shown in the figure below. Figure 1 As shown.

[0082] Please see Figure 2 As shown, the 1H NMR spectrum of the sulfide mineral collector based on thiophene-amide-sodium phosphate is as follows (the deuterated reagent is DMSO, and the chemical shift of the deuterated reagent is 2.5 ppm): 7.8~8.0 ppm and 7.3~7.5 ppm are two types of hydrogen atoms on the thiophene ring; 3.5~4.0 ppm are -O-CH2- atoms connected to the phosphate group; 3.2 ppm are hydrogen atoms on N-CH3 and N-CH2CH3; 2.0~2.4 ppm are hydrogen atoms on -CH2- atoms connected to the thiophene ring; 1.2~1.3 ppm are hydrogen atoms on -CH2- atoms connected to the carbonyl group; 0.8~1.0 ppm are divided into two types of hydrogen atoms: the first type is -O-CH2-CH2- hydrogen atoms separated from the phosphate group by a methylene group; the second type is -CH2-CH2-CH2- atoms connected to the tertiary amine group towards the thiophene ring.

[0083] Please see Figures 3 to 5 As shown, for the ore minerals in Table 1, Example 1 provides a method for collecting chalcopyrite and sphalerite using a sulfide mineral collector based on thiophene-amide-sodium phosphate, specifically including the following steps: S1. Mix 1000 g of dry ore with water to obtain 3 L of mineral slurry containing chalcopyrite and sphalerite. Place the mineral slurry into an XFG-3 flotation machine for collection and flotation of chalcopyrite and sphalerite. The water level should be adjusted to the appropriate position. Set the flotation machine impeller speed to 2000 r / min and adjust the slurry for 2 minutes.

[0084] S2. Under pH 9 conditions, add 0.1 kg / t of a sulfide mineral collector based on thiophene-amide-sodium phosphate; then add kerosene at a dosage of 100 g / t, and after 1 min, add 30 g / t of MIBC foaming agent.

[0085] After adding the frother MIBC and allowing it to act for 3 minutes, open the air valve to introduce air and begin flotation.

[0086] During the flotation process, bubbles are skimmed off every 5 seconds and water is added every 30 seconds, and this process is repeated.

[0087] The copper / zinc concentrates were collected at cumulative flotation times of 1, 3, 6, and 10 minutes, yielding four different copper / zinc concentrates. After filtration, the copper / zinc concentrates were dried in a 60°C oven, weighed, and the overall recovery rate was calculated.

[0088] The total recovery rate of copper / zinc concentrate is calculated by dividing the total mass of copper / zinc concentrate by the total mass of minerals containing chalcopyrite and sphalerite.

[0089] Comparative Examples 1-7 A method for collecting chalcopyrite and sphalerite differs from Example 1 in that, in step S2, instead of adding a sulfide mineral collector based on thiophene-amide-sodium phosphate, a different type of conventional black powder collector is added. The amount of collector used is 0.1 kg / t, as shown in Table 2. Other aspects are largely the same as in Example 1 and will not be repeated here.

[0090] Table 2 As shown in Table 2, compared with seven traditional flotation collectors such as sodium butylamine and isopropylammonium butylamine, the collector based on thiophene-amide-sodium phosphate salt in this application exhibits comprehensive and significant superiority in overall flotation performance. Specifically, its recovery rates for chalcopyrite and sphalerite reach 87% and 90%, respectively, which are not only far higher than all comparative reagents (the latter's highest recovery rates for chalcopyrite and sphalerite are only 67% and 72%, respectively), but more importantly, its recovery rate for associated pyrite is effectively suppressed to an extremely low level of 7%, while the recovery rates of pyrite for each comparative reagent are between 21% and 29%. This data indicates that the collector of this invention, through its unique molecular structure, achieves high selective inhibition of pyrite while powerfully collecting the target copper and zinc minerals. Its excellent selective separation effect is unattainable by traditional flotation collectors, fundamentally solving the industry problem of low separation efficiency and high intermingling content in copper-zinc-sulfur mixed concentrates.

[0091] Examples 2-6 and Comparative Examples 8-10 A method for collecting chalcopyrite and sphalerite differs from Example 1 in that the amount of sulfide mineral collector based on thiophene-amide-sodium phosphate salt is different in step S2, as shown in Table 3. The other steps are largely the same as in Example 1 and will not be repeated here.

[0092] Table 3 As shown in Table 3, the collector of the present invention can maintain excellent and stable sorting performance in a wide dosage range of 0.1 to 1.0 kg / t, forming a significant high-efficiency window.

[0093] Within this window, the recoveries of chalcopyrite and sphalerite remained stable at a high level of 87% to 93%, while the inhibition effect on pyrite was consistently excellent, with its recovery effectively controlled at a low level of 7%-9%. This demonstrates that the reagent has broad operational adaptability. In particular, when the dosage is 0.4 kg / t, the overall indicators reach the optimal balance point, achieving the best solution between high recovery rates of target minerals (chalcopyrite 90%, sphalerite 93%) and high inhibition rates of gangue minerals (pyrite only 7%).

[0094] In contrast, comparative data show that when the dosage is too low (0.05 kg / t), the collecting capacity is severely insufficient, and the recovery rate of the target mineral drops significantly. Conversely, when the dosage is too high (1.5 kg / t, especially 5.0 kg / t), not only does the recovery rate of chalcopyrite begin to decline, but more importantly, the selectivity for pyrite is completely lost, with the recovery rate rising sharply to 43%. This indicates that excessive reagent leads to severe non-selective adsorption. This comparison highlights the unique molecular structure of the collector of this invention, which gives it excellent adsorption characteristics at appropriate dosages. That is, it can saturately adsorb onto the surface of the target mineral without excessive and useless enrichment on gangue minerals, thus ensuring high selectivity in the separation process while guaranteeing efficient recovery.

[0095] Please see Figure 5 As shown, process mineralogical analysis of flotation tailings using polarized light microscopy reveals that the unrecovered chalcopyrite is not due to poor surface floatability or insufficient interaction with reagents, but rather because this mineral exists in a unique embedded form within the ore: it is tightly encased by pyrite, forming a core-shell or intergrowth structure. Under this tightly encased state, the exposed surface area of ​​the target chalcopyrite is extremely limited. Even with excellent collector molecular properties, it cannot effectively contact and adsorb onto the completely covered mineral interface, making it difficult to recover this resource during conventional physical separation. Therefore, the theoretical recovery rate of chalcopyrite cannot reach over 95%, primarily due to the inherent and unavoidable mineralogical encapsulation characteristics of the ore, rather than a problem with the collector's own collecting ability.

[0096] Examples 7-13 A method for collecting chalcopyrite and sphalerite differs from Example 1 in that the pH is different in step S2, as shown in Table 4. The other steps are largely the same as in Example 1 and will not be repeated here.

[0097] Table 4 Acidic comparisons were not included in the pH tests in Table 4, primarily due to considerations of the stability of the drug's molecular structure. The key functional groups in this collector molecule—sodium phosphate and amide groups—show significantly reduced chemical stability under acidic conditions. Sodium phosphate undergoes protonation to generate free phosphoric acid, leading to the loss of its water solubility and electrostatic pre-anchoring effect; the amide bond also carries the risk of acidic hydrolysis, resulting in molecular structure destruction and efficacy loss. Therefore, testing under acidic conditions cannot objectively evaluate the drug's performance and lacks practical comparative significance.

[0098] Furthermore, industrial flotation separation of chalcopyrite and sphalerite is almost always carried out under alkaline conditions to suppress pyrite and optimize separation. Data from Example 7 (pH=7) shows that under near-neutral conditions, the inhibitory effect of the reagent on pyrite (7% recovery) remains stable, and the recoveries of chalcopyrite and sphalerite reached 82% and 85%, respectively, demonstrating its effectiveness and adaptability over a wide pH range.

[0099] In summary, this invention designs and synthesizes a novel collector: sodium 3-[4-,5-(N-ethyl-N-methylcarbamoyl)pentyl]thiophene-2-propyl phosphate. This molecular design integrates three major functional modules: a rigid thiophene ring as a hydrophobic and adsorption-directing framework, an N-ethyl-N-methylamide group as an active center specifically coordinating with copper and zinc ions, and a terminal sodium phosphate salt providing excellent water solubility and electrostatic pre-adsorption capacity. Its mechanism of action is a multi-step synergistic process of "electrostatic pre-anchoring - planar adsorption - coordination locking": During the interaction between the reagent molecule and the mineral surface, its sodium phosphate group first rapidly adsorbs and accumulates in the interfacial region through electrostatic interactions. Simultaneously, it guides the hydrophilic functional group segments and hydrophobic framework molecular segments in the reagent molecule to arrange themselves in a specific spatial structure, providing the configurational preconditions for the subsequent hydrophobic association of the thiophene ring and the coordination chelation of the amide group. Subsequently, the thiophene ring is stably adsorbed through π-interactions. Finally, the amide group in the optimal spatial configuration forms a stable coordination with the metal site on the target mineral surface. This structure gives the molecule a high affinity for chalcopyrite and sphalerite. At the same time, the electrostatic repulsion of the phosphate group itself and the steric hindrance of the side chain work together to weaken the non-selective adsorption of non-target minerals such as pyrite from both physical and chemical perspectives.

[0100] Compared with traditional collectors, the collector proposed in this invention exhibits several advantages. First, its unique ionic sodium phosphate structure fundamentally solves the technical problem of difficult dispersion of traditional oily collectors in the aqueous phase, achieving efficient dissolution and convenient addition. Second, in terms of its mechanism of action, through the synergistic effect of multiple intramolecular functional groups, it achieves stronger and more selective adsorption of target minerals, obtaining excellent copper-zinc separation under neutral to weakly alkaline conditions, significantly reducing dependence on high-alkali processes.

[0101] 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 thiophene-amide-sodium phosphate salt based sulphide ore collector characterized in that, The molecular structure is as follows: 。 2. A process for the preparation of a thiophene-amide-sodium phosphate salt based sulphide mineral collector characterized in that, The synthetic process for preparing the thiophene-amide-sodium phosphate salt-based sulfide ore collector of claim 1 comprises the following steps: A1: Synthesis of amide side chain intermediate 5-(N-ethyl-N-methyl carbamoyl) pentyl bromide; To the monomethyl glutarate anhydrous THF solution, drop borane-dimethyl sulfide complex, the molar equivalent ratio of monomethyl glutarate and borane-dimethyl sulfide complex is 3.33~3.50; after drop completion, it is reacted at room temperature for 2~8 hours to obtain alcohol; then, the obtained alcohol is dissolved in dichloromethane, and triphenylphosphine and N-bromosuccinimide are added in sequence, after stirring reaction is completed, 5-bromopentanoic acid is obtained by purification; wherein the molar ratio of monomethyl glutarate, triphenylphosphine and N-bromosuccinimide is 68: (80~100): (80~100); The obtained 5-bromopentanoic acid is dissolved in anhydrous dichloromethane, and DMF is added as a catalyst; at 0℃, oxalyl chloride is slowly added dropwise, and the molar equivalent ratio of 5-bromopentanoic acid and oxalyl chloride is 1: (1~3); after drop completion, it is stirred at room temperature for 2-3 hours to obtain unpurified 5-bromopentyl chloride; Under the conditions of 0℃ and stirring, the unpurified 5-bromopentyl chloride anhydrous dichloromethane solution is slowly added dropwise to the anhydrous dichloromethane solution of N-ethylmethylamine and triethylamine; wherein the molar equivalent ratio of 5-bromopentyl chloride, N-ethylmethylamine and triethylamine is 1: (1~1.5): 1; after reaction is completed, the target intermediate 5-(N-ethyl-N-methyl carbamoyl) pentyl bromide is obtained after purification; A2: Introducing thiophene skeleton by Negishi coupling reaction; 3-bromothiophene and anhydrous THF are added, and i-PrMgCl·LiCl solution is added dropwise, wherein the molar equivalent ratio of 3-bromothiophene and i-PrMgCl·LiCl is 1: (1~1.3); after drop completion, it is stirred at-20℃ for 1~6 hours to generate thiophene-3-yl Grignard reagent; the thiophene-3-yl Grignard reagent solution is quickly added into ZnCl2 solution, and stirred for 30 minutes to generate the corresponding zinc reagent solution; The bromide 5-(N-ethyl-N-methyl carbamoyl) pentyl bromide prepared in step A1 is dissolved in anhydrous THF with Pd(dppf)Cl2 in a molar equivalent ratio of (20~25): 1; The prepared zinc reagent solution is moved to the solution containing catalyst Pd(dppf)Cl2 and substrate 5-(N-ethyl-N-methyl carbamoyl) pentyl bromide; after reaction is completed, purification is performed to obtain 3-[4-, 5-(N-ethyl-N-methyl carbamoyl) pentyl] thiophene; A3: Introducing phosphonic acid propyl ester side chain; Under the protection of nitrogen and at-78℃, n-BuLi is slowly added dropwise to the anhydrous THF solution of the product of step A2; wherein the molar equivalent ratio of 3-[4-, 5-(N-ethyl-N-methyl carbamoyl) pentyl] thiophene and n-BuLi is 1: (1~1.5); after drop completion, it is stirred at-78℃ for 1 hour to obtain a transition lithiumate solution; The 1,3-dibromopropane is dissolved in a small amount of THF, and the molar ratio of 1,3-dibromopropane to the product of A2 is (3-5):1, and then the solution is slowly added to the above transition lithium solution; after the drop is completed, it is slowly raised to room temperature and stirred overnight, and then purified to obtain a 3-(3-bromopropyl)thiophene derivative; The obtained 3-(3-bromopropyl)thiophene derivative is mixed with potassium acetate in a molar ratio of 1:(2.5-5) in DMF, heated to 80°C and stirred for 6-8 hours to obtain an unpurified alcohol bromopropyl alcohol; The unpurified alcohol bromopropyl alcohol is dissolved in anhydrous acetonitrile in a molar ratio of 1:(2.5-4), and dibenzyl chlorophosphate is added dropwise, wherein the molar ratio of dibenzyl chlorophosphate to unpurified alcohol bromopropyl alcohol is (1.5-2):1; purification to obtain a dibenzyl phosphate-protected precursor; A4: removing the protecting group to form a salt target compound; The precursor obtained in step A3 is dissolved in anhydrous methanol / tetrahydrofuran mixed solvent, and palladium-carbon is added, wherein the mass ratio of palladium-carbon to the precursor obtained in A3 is 1:10; stirred vigorously at room temperature under normal pressure hydrogen atmosphere for 6-12 hours, after the reaction is completed, the palladium-carbon is removed by filtering with 400 mesh size range diatomite, and the filtrate is concentrated under reduced pressure to obtain a phosphoric acid compound; The above phosphoric acid compound is dissolved in a methanol / water mixed solvent, and an aqueous sodium hydroxide solution is added dropwise under ice bath cooling until the pH is 7-8, and the solution is concentrated to dryness under reduced pressure at low temperature to obtain a crude salt; recrystallization purification is carried out with hot isopropyl alcohol or ethanol / acetone mixed solvent; The purified solid is dried in a vacuum drying oven to obtain the final product 3-[4-,5-(N-ethyl-N-methyl aminocarbonyl) pentyl] thiophene-2-propyl sodium phosphate.

3. A method of collecting chalcopyrite and sphalerite, characterized by, The thiophene-amide-phosphoric acid sodium salt-based sulfide ore collector of claim 1 comprises the following steps: S1, mixing the minerals containing chalcopyrite and sphalerite with water to form a slurry; S2, adjusting the pH of the slurry to 7-14, adding the thiophene-amide-phosphoric acid sodium salt-based sulfide ore collector, then adding kerosene, and then adding the frother MIBC; after 2-5 minutes, air is introduced to start flotation.

4. The method of collecting chalcopyrite and sphalerite according to claim 3, characterized in that, The total amount of the thiophene-amide-phosphoric acid sodium salt-based sulfide ore collector is 0.1-1 kg / t.

5. The method of collecting chalcopyrite and sphalerite according to claim 3, characterized in that, The amount of kerosene is 50-100 g / t.

6. The method of collecting chalcopyrite and sphalerite according to claim 3, characterized in that, The amount of the frother MIBC is 25-50 g / t.

7. The method of collecting chalcopyrite and sphalerite according to claim 3, characterized in that, During the flotation process, the froth is scraped every 5-10 seconds, and water is added every 30-40 seconds.

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