A copper flotation collector and a method for preparing the same

Abstract

The present application relates to the field of frother, in particular to a kind of copper flotation collector frother and preparation method thereof, by weight parts, including the following raw materials: N,N-dibutyl dithiocarbamic acid propyl cyanurate 100-120 parts, O-butyl-N-isobutyl thiopropyl carbamate 12-18 parts, xanthate 12-18 parts, phosphate ester polypropylene glycol ether 15-20 parts, modified betaine 5-8 parts, alcohol ether 3-5 parts, slime inhibitor 1-3 parts, alcohol ether carboxylate 2-5 parts, sorbitan monooleate 0.8-1.2 parts. Through the synergies of each raw material, the collector capacity, selectivity in copper flotation process can be effectively improved, and the reagent stability is good.

Description

Technical Field

[0001] This invention relates to the field of foaming agents, and more specifically, to a copper flotation collecting foaming agent and its preparation method. Background Technology

[0002] Copper minerals are diverse, but the two main categories with mining value are copper sulfide ores and copper oxide ores. Among them, copper sulfide ores are the primary source of copper extraction, and common examples include: chalcopyrite (CuFeS2, containing 34.6% copper), chalcocite (Cu2S, containing 79.9% copper), bornite (Cu5FeS4, containing 63.3% copper), and covellite (CuS, containing 66.5% copper). Copper sulfide ores are usually associated with pyrite, pyrrhotite, and useful components such as lead, zinc, gold, and silver. Gangue minerals commonly include quartz, sericite, talc, serpentine, and chlorite.

[0003] Currently, the collectors commonly used in the flotation of copper sulfide ore are mainly classified into the following categories: (1) Xanthates (xanthates) Representative pharmaceutical agents include ethyl xanthate, butyl xanthate, isobutyl xanthate, and isopentyl xanthate.

[0004] These reagents have strong collecting power, wide availability, and low cost, and are effective in collecting most copper sulfide ores. However, they have poor selectivity and also have strong collecting power for iron sulfide minerals such as pyrite and pyrrhotite, resulting in high levels of impurities such as sulfur and iron in the copper concentrate; they are easily decomposed and ineffective in acidic or neutral slurries; and they have a strong odor, which is unfriendly to the operating environment.

[0005] (2) Thiophosphates (black medicine) Representative reagents: Butylammonium black powder (No. 226 black powder), cresol black powder, No. 208 black powder, etc.

[0006] These reagents have better selectivity than xanthates, but weaker pyrite-collecting ability, making them suitable for copper-sulfur separation. Their foaming properties are brittle, which is beneficial for beneficiation operations. However, their collecting ability is relatively weaker than xanthates, and their recovery effect on fine-grained copper minerals is not ideal. Some black reagents (such as cresol black reagent) are toxic and have poor environmental performance.

[0007] (3) Sulfur-nitrogen compounds (dithiocarbamates / esters) Representative reagents include: ethyl thiocyanate (sodium N,N-diethyldithiocarbamate), ester-105 (N,N-diethyldithiocarbamate propionitrile), butyl ester-105 (N,N-dibutyldithiocarbamate propionitrile), etc.

[0008] It exhibits good selectivity, strong collecting ability, and fast flotation speed, with better collecting effect on copper mineral intergrowths than xanthate. However, the collecting power of short-chain (such as ethyl) structures is still insufficient, and it has poor adaptability to fine-grained embedded copper minerals; the synthesis process of some reagents is relatively complex and costly.

[0009] (4) Thiocarbamates Representative pharmaceutical agents: Z-200 (O-isopropyl-N-ethyl thiocarbamate), O-butyl-N-isobutyl thiocarbamate, etc.

[0010] It exhibits excellent selectivity, but has weak collecting ability for pyrite, making it suitable for copper-sulfur separation. It requires low dosage and has good water solubility. However, its collecting ability is relatively weak, often necessitating its use in combination with other collectors. It is essentially ineffective against copper oxide minerals.

[0011] (5) Compound / combined collectors The formulations disclosed in compound products of the above-mentioned drugs, such as CN116371609A and CN109482355B.

[0012] It can leverage the synergistic effect of its components, resulting in superior overall performance compared to single reagents. However, some formulations contain hydrocarbon oils such as kerosene and aviation kerosene, which can cause easily floating gangues such as talc and serpentine to float, reducing the grade of the concentrate. Some formulations use industrial byproducts such as fusel oil, leading to poor batch stability of the reagents. Furthermore, the compounding process sometimes requires the use of organic solvents such as ethanol, increasing costs and environmental burden.

[0013] Frothing agents are reagents used in the flotation process to promote the dispersion of air into fine bubbles in the pulp, prevent bubble coalescence, and improve foam stability. Traditional frothers (such as pine oil, No. 2 oil, methyl isobutyl methanol (MIBC), and polypropylene glycol ether) can effectively form foam, providing a flotation carrier for hydrophobic minerals. When used in conjunction with collectors, they can achieve better flotation performance. Among them, synthetic frothers such as MIBC and polypropylene glycol ether have advantages such as fine and uniform foam, odorless properties, and good biodegradability. Currently, commercially available frothers have the following disadvantages: (1) Traditional foaming agents have a single function, only playing a role in stabilizing foam and not having the ability to collect foam. They need to be used in combination with collectors, which increases the types of agents added and the difficulty of management.

[0014] (2) Some foaming agents (such as pine oil) are limited by turpentine raw materials, resulting in large fluctuations in production and price.

[0015] (3) Most foaming agents are sensitive to conditions such as fine mud, hard water and low temperature in the slurry and have poor adaptability.

[0016] The integrated frothing and bubbling agent, as described in CN120607897A, has two functions, but the synthesis process is extremely complex. The raw materials contain highly toxic and polluting substances such as fluorine and pyridine, making industrialization extremely difficult.

[0017] In summary, existing flotation collectors and frothers for copper sulfide ores still suffer from insufficient selectivity, limited ability to collect fine-grained and complexly embedded copper minerals, poor synergy between collectors and frothers, and difficulty in precisely controlling their interaction when added separately.

[0018] Therefore, there is an urgent need to develop a new type of collector-foaming agent that is simple to prepare, does not use organic solvents or toxic raw materials, has both strong collecting and excellent foaming properties, good selectivity, is resistant to mud and low temperatures, and is suitable for complex copper ores, in order to meet market demand. Summary of the Invention

[0019] The purpose of this invention is to provide a copper flotation frother that, through the synergistic effect of various raw materials, can effectively improve the collection capacity and selectivity in the copper flotation process, and the agent has good stability.

[0020] Another objective of this invention is to provide a method for preparing a copper flotation collector foaming agent, which, through a combination of stepwise emulsification and high-pressure homogenization, yields a stable fine emulsion with good foaming agent stability.

[0021] The technical problem solved by this invention is achieved by the following technical solution.

[0022] On one hand, embodiments of the present invention provide a copper flotation collector foaming agent, which, by weight, comprises the following raw materials: 100-120 parts of N,N-dibutyldithiocarbamate propionitrile, 12-18 parts of O-butyl-N-isobutylthiocarbamate, 12-18 parts of xanthate, 15-20 parts of phosphate-modified polypropylene glycol ether, 5-8 parts of modified betaine, 3-5 parts of alcohol ether, 1-3 parts of mud inhibitor, 2-5 parts of alcohol ether carboxylate, and 0.8-1.2 parts of sorbitan monooleate.

[0023] In some embodiments of the present invention, the raw materials include the following by weight: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 15 parts of O-butyl-N-isobutylthiocarbamate, 15 parts of xanthate, 18 parts of phosphorylated polypropylene glycol ether, 7 parts of modified betaine, 4 parts of alcohol ether, 2 parts of mud inhibitor, 3 parts of alcohol ether carboxylate, and 1 part of dehydrated sorbitan monooleate.

[0024] In some embodiments of the present invention, the modified betaine is prepared by the following steps: Add cocoyl dimethyl tertiary amine to water and isopropanol, stir and heat to 50-60℃, add 10-15% NaOH aqueous solution dropwise, adjust the pH of the system to 9.0-9.5, and obtain the reaction solution; Dissolve 2-chloroethylphosphonic acid in water and adjust the pH to 7 with 10-15% NaOH to obtain the phosphoric acid reagent; Add phosphoric acid reagent dropwise to the reaction solution and stir at 60-65℃ for 6-8 hours, maintaining pH 8.5-9.0 during stirring. Cool the reaction system to room temperature, adjust the pH to 3-4, and evaporate by rotary evaporation to obtain a concentrated solution. Add anhydrous ethanol, heat to 50-55℃, stir for 30-40 minutes, hot filter, and evaporate the filtrate by rotary evaporation to obtain a paste. The paste was dissolved in water, and the pH was adjusted to 6.5-7.0 to obtain the modified betaine.

[0025] In some embodiments of the present invention, the alcohol ether is at least one of ethylene glycol tert-butyl ether, diethylene glycol tert-butyl ether, polypropylene glycol ether, ethylene glycol butyl ether, and propylene glycol ether.

[0026] In some embodiments of the present invention, the sludge inhibitor is at least one of sodium polyepoxysuccinate, polyaspartic acid, and carboxymethyl cellulose.

[0027] In some embodiments of the present invention, the xanthate is at least one selected from sodium isobutyl xanthate, sodium isopentyl xanthate, sodium ethyl xanthate, and sodium propyl xanthate.

[0028] On the other hand, embodiments of the present invention provide a method for preparing a copper flotation collector foaming agent, comprising the following steps: S1: N,N-dibutyldithiocarbamate propionitrile, O-butyl-N-isobutylthiocarbamate, xanthate, phosphorylated polypropylene glycol ether, alcohol ether, and sorbitan monooleate are added sequentially to a stirred reactor and stirred for 10-20 minutes at 20-40℃ and 200-500 rpm to obtain an oily premix. S2: Dissolve the modified betaine, alcohol ether carboxylate, and mud inhibitor in 3-5 times their weight of deionized water, stir well, and obtain an aqueous solution. S3: Add the aqueous solution of S2 to the oily premix of S1, and stir for 15-30 minutes at 25-35℃ and 300-600rpm to obtain a crude emulsion; S4: The crude emulsion of S3 is processed 1-3 times in a high-pressure homogenizer at a homogenization pressure of 20-80 MPa and a temperature of 25-40℃ to obtain a fine emulsion. S5: Heat-treat and mature the fine emulsion of S4 by stirring at 40-60℃ for 30-60 minutes; S6: Cool to room temperature, filter, and let stand to defoam, thus obtaining the foam-collecting agent.

[0029] In some embodiments of the present invention, in step S4, the pressure of high-pressure homogenization is 40-60 MPa, and the number of homogenization steps is 2.

[0030] In some embodiments of the present invention, in step S5, the heat treatment temperature is 45-55°C and the time is 40-50 minutes.

[0031] In some embodiments of the present invention, S1 and / or S3 further include applying pulsed ultrasound treatment, wherein the pulsed ultrasound frequency is 28-40 kHz, the power density is 0.3-0.8 W / mL, and the treatment time is 5-15 minutes.

[0032] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The copper flotation frother provided by this invention can effectively improve the collection capacity and selectivity in the copper flotation process through the synergistic effect of various raw materials, and the agent has good stability.

[0033] N,N-Dibutyldithiocarbamate propionitrile, combined with O-butyl-N-isobutylthiocarbamate and xanthate, are all sulfur-containing organic compounds with a strong affinity for copper minerals. N,N-Dibutyldithiocarbamate propionitrile and O-butyl-N-isobutylthiocarbamate belong to the thiocarbamate class, offering better selectivity and lower dosage compared to traditional xanthates, thus reducing the collection of impurities. Xanthates (such as isobutyl / isopentyl xanthate) have strong collecting ability but relatively weak selectivity. The combination of these three compounds in the proportions described in this application creates a synergistic effect of strong collecting and high selectivity, simultaneously improving the grade and recovery rate of copper concentrate.

[0034] Phosphate-modified polypropylene glycol ether is a highly efficient foaming agent that produces fine, stable foam that is easy to defoam. Sorbitol monooleate, as a nonionic surfactant, enhances the strength of the foam film, extends foam life, and prevents premature foam breakage that could lead to mineral detachment. The alcohol ether acts as both a foaming aid and improves the dispersibility of reagents in the pulp, while also promoting the adhesion of fine mineral particles to air bubbles, thereby enhancing the flotation effect on fine minerals.

[0035] Because copper ore often contains gangue that is prone to becoming muddy, the slime will indiscriminately cover the mineral surface, reducing the efficiency of the collector. The slime inhibitor added in this application can preferentially adsorb onto the slime surface, making the slime hydrophilic and dispersed, thereby eliminating the interference of slime on the flotation process and improving the grade of copper concentrate.

[0036] Modified betaine and alcohol ether carboxylates are both amphoteric / anionic green surfactants. They can reduce the interfacial tension between oily collector components and water, helping to form stable oil-in-water emulsions and preventing reagent stratification and failure. Simultaneously, these surfactants have good biodegradability and low toxicity, preventing the introduction of toxic substances into flotation wastewater. Modified betaine exhibits good salt and hard water resistance, making it better adaptable to different water qualities.

[0037] The copper flotation frother preparation method provided by this invention, through a combination of stepwise emulsification and high-pressure homogenization, yields a stable fine emulsion. Steps S1 and S2 prepare the oil phase and aqueous phase respectively, which are then mixed, avoiding localized uneven reactions caused by direct mixing. The high-pressure homogenization in step S4 breaks the emulsion droplets down to the nanometer or submicron level, allowing the frother to be stored for a long time without stratification and ready for direct use after defoaming. The agent diffuses instantaneously and uniformly in the slurry, acting rapidly, and the fine droplets can more effectively adsorb onto the surface of fine-grained copper minerals, improving the recovery rate of fine-grained copper.

[0038] Step S5 involves maintaining the temperature at 40-60℃ and stirring for 30-60 minutes. This process eliminates the internal stress generated during homogenization, allowing surfactant molecules to arrange themselves more tightly and orderly at the oil-water interface, further improving the kinetic stability of the emulsion and preventing demulsification during transportation or long-term flotation. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0041] On one hand, embodiments of the present invention provide a copper flotation collector foaming agent, which, by weight, comprises the following raw materials: 100-120 parts of N,N-dibutyldithiocarbamate propionitrile, 12-18 parts of O-butyl-N-isobutylthiocarbamate, 12-18 parts of xanthate, 15-20 parts of phosphate-modified polypropylene glycol ether, 5-8 parts of modified betaine, 3-5 parts of alcohol ether, 1-3 parts of mud inhibitor, 2-5 parts of alcohol ether carboxylate, and 0.8-1.2 parts of sorbitan monooleate.

[0042] Preferred ingredients, by weight, include the following raw materials: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 15 parts of O-butyl-N-isobutylthiocarbamate, 15 parts of xanthate, 18 parts of phosphorylated polypropylene glycol ether, 7 parts of modified betaine, 4 parts of alcohol ether, 2 parts of mud inhibitor, 3 parts of alcohol ether carboxylate, and 1 part of dehydrated sorbitan monooleate.

[0043] The modified betaine is prepared by the following steps: Add cocoyl dimethyl tertiary amine to water and isopropanol, stir and heat to 50-60℃, add 10-15% NaOH aqueous solution dropwise, adjust the pH of the system to 9.0-9.5, and obtain the reaction solution; Dissolve 2-chloroethylphosphonic acid in water and adjust the pH to 7 with 10-15% NaOH to obtain the phosphoric acid reagent; Add phosphoric acid reagent dropwise to the reaction solution and stir at 60-65℃ for 6-8 hours, maintaining pH 8.5-9.0 during stirring. Cool the reaction system to room temperature, adjust the pH to 3-4, and evaporate by rotary evaporation to obtain a concentrated solution. Add anhydrous ethanol, heat to 50-55℃, stir for 30-40 minutes, hot filter, and evaporate the filtrate by rotary evaporation to obtain a paste. The paste was dissolved in water, and the pH was adjusted to 6.5-7.0 to obtain the modified betaine.

[0044] The modified betaine contains phosphonate groups, which react with the para-Ca in the slurry. 2+ Mg 2+ It possesses moderate chelating ability, preferentially forming soluble complexes with these ions in the slurry, preventing them from combining with xanthate ions to form insoluble xanthate precipitates. Under hard water conditions, it can increase the effective concentration of the collector.

[0045] Modified betaine molecules possess long hydrophobic chains and weak chelating head groups, which are effective against Cu. 2+ The chelation stability constant of modified betaine is between that of calcium and magnesium and strong collectors. It can temporarily complex copper ions generated by oxidation and dissolution in the slurry, preventing free copper from reacting rapidly with xanthate to form hydrophobic flocs that cannot effectively adhere to bubbles and are thus lost. The chelation strength of copper ions complexed by modified betaine is weaker than the bonding force between xanthate and copper atoms on the surface of copper minerals. When the modified betaine-copper complex encounters the surface of copper minerals, xanthate can displace betaine, improving collection efficiency. On the surface of copper minerals, modified betaine can adsorb in areas not completely covered by xanthate or between xanthate molecules, forming a denser and thicker mixed adsorption layer through hydrophobic association between hydrophobic carbon chains and xanthate carbon chains.

[0046] The modified betaine and alcohol ether carboxylate work synergistically to form a nanoscale emulsion of thiocarbamate in the aqueous phase. The steric hindrance and electrostatic repulsion prevent droplet aggregation, allowing the foaming agent to be stored for a long time without precipitation or stratification.

[0047] Modified betaine molecules carry both positive charges (quaternary ammonium nitrogen) and negative charges (phosphonate), which can adsorb onto the surface of mineral slime particles with different charges (such as positively charged talc and negatively charged kaolinite). Through charge neutralization and steric hindrance, the slime is kept in a dispersed state, preventing it from forming a capping layer on the surface of copper minerals. This reduces inclusions in the flotation froth, improves the concentrate grade, and ensures good pulp fluidity, making it less prone to overflow.

[0048] The alcohol ether is at least one of ethylene glycol tert-butyl ether, diethylene glycol tert-butyl ether, polypropylene glycol ether, ethylene glycol butyl ether, and propylene glycol ether.

[0049] The sludge inhibitor is at least one of sodium polyepoxysuccinate, polyaspartic acid, and carboxymethyl cellulose.

[0050] The xanthate is at least one of sodium isobutyl xanthate, sodium isoamyl xanthate, sodium ethyl xanthate, and sodium propyl xanthate.

[0051] The effects of each raw material in the copper flotation and frother provided in this embodiment of the invention are as follows.

[0052] N,N-Dibutyldithiocarbamate propionitrile, as a core selective collector, contains a dithiocarbamate group in its molecule, enabling it to form stable complexes with the surfaces of sulfide minerals such as copper and copper-zinc, exhibiting strong hydrophobicity. Compared to xanthates, it offers higher selectivity and exhibits weaker collecting power for non-target minerals such as pyrite and sphalerite, which is beneficial for improving copper concentrate grades. The propionitrile group imparts certain water solubility and dispersibility, while simultaneously reducing the amount of reagent required.

[0053] O-Butyl-N-isobutylthiocarbamate, as an auxiliary collector and frother, exhibits good collecting properties for copper minerals and also possesses frother properties. Its addition enhances the collecting ability for difficult-to-float copper ores (such as secondary copper and post-sulfurization flotation of copper oxide), while simultaneously adjusting foam characteristics to prevent excessively viscous foam.

[0054] Sodium isobutyl xanthate (xanthate, or xanthate) reacts rapidly with copper surfaces to form copper xanthate salts, exhibiting strong hydrophobicity. It possesses strong collecting properties, improving the recovery rate of fine-grained copper ores and refractory copper ores.

[0055] Phosphorylated polypropylene glycol ether is obtained by phosphorylation of polypropylene glycol ether. It has a moderate hydrophilic-hydrophobic balance (HLB) value, which can rapidly reduce the gas-liquid interfacial tension, producing a large amount of fine, uniform foam that is not prone to coalescence. Its foam layer has good fluidity, which is beneficial for the separation of minerals from the foam. It is not sensitive to hard water and is suitable for various water qualities.

[0056] Sorbitol monooleate can adsorb onto bubble-filled liquid films, increasing film cohesion and elasticity, and preventing premature bubble rupture or coalescence. It also acts as an oil-soluble emulsifier, forming stable W / O or O / W emulsions at the oil-water interface, improving the stability of pharmaceuticals during storage.

[0057] Ethylene glycol tert-butyl ether (ethanol ether), with its hydrophilic hydroxyl group and hydrophobic alkyl ether chain, can significantly reduce the adsorption time of foaming agents at the gas-liquid interface, resulting in faster foaming. It also improves the dispersibility of various substances in the slurry and enhances the probability of collision between fine mineral particles and bubbles.

[0058] Alcohol ether carboxylates (such as fatty alcohol polyoxyethylene ether carboxylate) have excellent water solubility and hard water resistance. When used in combination with modified betaine, they can form a mixed adsorption layer on the surface of oil droplets, preventing droplet aggregation through a dual mechanism of electrostatic and steric hindrance, thereby improving the long-term stability of the agent.

[0059] Slime inhibitors can preferentially adsorb onto the surface of positively charged slimes (such as talc, kaolinite, and chlorite). Through strong hydrophilicity and steric hindrance, they keep the slimes dispersed and hydrophilic, preventing them from covering the surface of copper minerals.

[0060] The preparation method of the above-mentioned copper flotation collector foaming agent includes the following steps: S1: N,N-dibutyldithiocarbamate propionitrile, O-butyl-N-isobutylthiocarbamate, xanthate, phosphorylated polypropylene glycol ether, alcohol ether, and sorbitan monooleate are added sequentially to a stirred reactor and stirred for 10-20 minutes at 20-40℃ and 200-500 rpm to obtain an oily premix. S2: Dissolve the modified betaine, alcohol ether carboxylate, and mud inhibitor in 3-5 times their weight of deionized water, stir well, and obtain an aqueous solution. S3: Add the aqueous solution of S2 to the oily premix of S1, and stir for 15-30 minutes at 25-35℃ and 300-600rpm to obtain a crude emulsion; S4: The crude emulsion of S3 is processed 1-3 times in a high-pressure homogenizer at a homogenization pressure of 20-80 MPa and a temperature of 25-40℃ to obtain a fine emulsion. S5: Heat-treat and mature the fine emulsion of S4 by stirring at 40-60℃ for 30-60 minutes; S6: Cool to room temperature, filter, and let stand to defoam, thus obtaining the foam-collecting agent.

[0061] In step S4, the pressure of high-pressure homogenization is 40-60 MPa, and the homogenization is performed twice.

[0062] In step S5, the heat treatment temperature is 45-55℃ and the time is 40-50 minutes.

[0063] In steps S1 and / or S3, pulsed ultrasound treatment is also applied, with a pulsed ultrasound frequency of 28-40 kHz, a power density of 0.3-0.8 W / mL, and a treatment time of 5-15 minutes.

[0064] Pulsed ultrasound (frequency 28-40 kHz, power 0.3-0.8 W / mL) is applied in steps S1 and / or S3. The ultrasonic cavitation effect generates local high temperature and pressure and strong shock waves, which can further disintegrate any possible drug agglomerates, promote the mixing of oil phase components at the molecular level, and, in conjunction with high-pressure homogenization during emulsification, further refine the droplet size to a narrower distribution range, thereby improving the efficiency of drug action per unit mass.

[0065] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0066] Example 1 1. Preparation of modified betaine: Weigh 23g of cocoyl dimethyl tertiary amine, add 50mL of deionized water and 20mL of isopropanol, stir and heat to 60℃. Slowly add 10% NaOH aqueous solution to adjust the pH of the system to 9.0-9.5, and keep it stable for 5 minutes without decreasing, to obtain the reaction solution.

[0067] Weigh 17g of 2-chloroethylphosphonic acid, dissolve it in 20mL of deionized water, and adjust the pH to ≈7 with 10% NaOH to obtain the phosphate reagent.

[0068] Slowly add the phosphoric acid reagent dropwise into the reaction flask at a rate of approximately 1 drop per second, maintaining the temperature at 60-65°C and stirring for 6-8 hours. During the reaction, take a sample every hour to measure the pH. If the pH drops below 8, add a small amount of NaOH solution to maintain the pH at 8.5-9.0.

[0069] After the reaction is complete, the reaction system is cooled to room temperature, and the pH is adjusted to 3-4 with dilute hydrochloric acid (1 mol / L) to protonate the unreacted 2-chloroethylphosphonic acid. Isopropanol and some water are removed by rotary evaporation to obtain a viscous concentrate. 50 mL of anhydrous ethanol is added, and the mixture is heated to 50°C and stirred for 30 minutes. Inorganic salts (such as NaCl) are removed by hot filtration. The ethanol is removed by rotary evaporation of the filtrate to obtain a pale yellow paste. The paste is dissolved in 20 mL of deionized water, and the pH is adjusted to 6.5-7.0 with 5% NaOH to obtain a modified betaine aqueous solution (solid content approximately 30-40%).

[0070] 2. Prepare phosphorylated polypropylene glycol ether according to the following steps. Add polypropylene glycol ether (PPG-400) to a three-necked flask and heat to 50-60℃ (water bath) while stirring. Add phosphorus pentoxide in batches, about 2-3g each time, and add the next batch only after the reaction has stabilized. The total addition time should be controlled at 20-30 minutes.

[0071] Molar ratio of feed ingredients: PPG (as OH): P2O5 = 2.5:1.

[0072] After adding P2O5, raise the temperature to 70-80℃ and continue stirring for 2-4 hours. The system will gradually thicken and may turn yellow or brown. After the reaction is complete, cool to below 50℃ and slowly add 10-20 mL of deionized water. Unreacted P2O5 and acid anhydride bonds will hydrolyze to form phosphoric acid. Then add 30 mL of anhydrous ethanol and stir for 30 minutes to ensure the product is uniformly dissolved.

[0073] Adjust the pH to 6.5-7.5 using 40% NaOH solution (based on a pH meter) to neutralize the free phosphoric acid. Add 1-2g of activated carbon, heat to 60℃, stir and decolorize for 30 minutes, then filter while hot. Distill the filtrate under reduced pressure (60-70℃, vacuum 0.09MPa) to remove ethanol and some water, controlling the solid content (mass fraction of phosphoric acid esterified polypropylene glycol ether) of the product to around 85%, yielding a viscous liquid. The free phosphoric acid content in the product is <10mgKOH / g.

[0074] 2. Prepare a foaming agent according to the following formula and method: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 15 parts of O-butyl-N-isobutylthiocarbamate, 15 parts of xanthate (sodium isobutyl xanthate), 18 parts of phosphate-esterified polypropylene glycol ether, 7 parts of modified betaine, 4 parts of alcohol ether (ethylene glycol tert-butyl ether), 2 parts of mud inhibitor (sodium polyepoxysuccinate), 3 parts of alcohol ether carboxylate, and 1 part of dehydrated sorbitan monooleate.

[0075] All of the above raw materials are available on the market, as shown in Table 1.

[0076] Table 1

[0077] Preparation method of foaming agent: S1: N,N-dibutyldithiocarbamate propionitrile, O-butyl-N-isobutylthiocarbamate, xanthate, phosphorylated polypropylene glycol ether, alcohol ether, and sorbitan monooleate were added sequentially to a stirred reactor and stirred for 20 minutes at 30°C and 300 rpm to obtain an oily premix. S2: Dissolve the modified betaine, alcohol ether carboxylate, and mud inhibitor in 5 times their weight of deionized water, stir well, and obtain an aqueous solution. S3: Add the aqueous solution of S2 to the oily premix of S1, and stir for 30 minutes at 30°C and 500 rpm to obtain a crude emulsion. S4: The crude emulsion of S3 is processed three times in a high-pressure homogenizer at a homogenization pressure of 60 MPa and a temperature of 30 °C to obtain a fine emulsion. S5: Heat-treat and mature the fine emulsion of S4 at 50°C for 40 minutes; the heat treatment temperature is 50°C and the time is 40 minutes.

[0078] S6: Cool to room temperature, filter, and let stand to defoam, thus obtaining the foam-collecting agent.

[0079] Example 2 Based on the raw materials and preparation method of Example 1, the formulation of the foaming agent in this example is set as follows: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 12 parts of O-butyl-N-isobutylthiocarbamate, 12 parts of xanthate (sodium isobutyl xanthate), 15 parts of phosphate-esterified polypropylene glycol ether, 5 parts of modified betaine, 3 parts of alcohol ether (ethylene glycol tert-butyl ether), 1 part of mud inhibitor (sodium polyepoxysuccinate), 2 parts of alcohol ether carboxylate, and 0.8 parts of sorbitan monooleate.

[0080] Example 3 Based on the raw materials and preparation method of Example 1, the formulation of the foaming agent in this example is set as follows: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 18 parts of O-butyl-N-isobutylthiocarbamate, 18 parts of xanthate (sodium isobutyl xanthate), 20 parts of phosphate-modified polypropylene glycol ether, 8 parts of modified betaine, 5 parts of alcohol ether (ethylene glycol tert-butyl ether), 3 parts of mud inhibitor (sodium polyepoxysuccinate), 5 parts of alcohol ether carboxylate, and 1.2 parts of sorbitan monooleate.

[0081] Example 4 Based on the raw materials and preparation method of Example 1, the formulation of the foaming agent in this example is set as follows: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 18 parts of O-butyl-N-isobutylthiocarbamate, 12 parts of xanthate (sodium isobutyl xanthate), 20 parts of phosphate-modified polypropylene glycol ether, 5 parts of modified betaine, 5 parts of alcohol ether (ethylene glycol tert-butyl ether), 3 parts of mud inhibitor (sodium polyepoxysuccinate), 2 parts of alcohol ether carboxylate, and 1.2 parts of sorbitan monooleate.

[0082] Example 5 Based on the raw materials and preparation method of Example 1, the formulation of the foaming agent in this example is set as follows: 120 parts of N,N-dibutyldithiocarbamate propionitrile, 12 parts of O-butyl-N-isobutylthiocarbamate, 18 parts of xanthate (sodium isobutyl xanthate), 15 parts of phosphate-modified polypropylene glycol ether, 8 parts of modified betaine, 3 parts of alcohol ether (ethylene glycol tert-butyl ether), 3 parts of mud inhibitor (sodium polyepoxysuccinate), 2 parts of alcohol ether carboxylate, and 0.8 parts of sorbitan monooleate.

[0083] Comparative Example 1 The difference from Example 1 is that betaine is used instead of the modified betaine in Example 1, while the other raw materials, proportions and preparation methods are the same as in Example 1.

[0084] Comparative Example 2 The difference from Example 1 is that polypropylene glycol ether is used instead of the phosphoric acid esterified polypropylene glycol ether in Example 1, while the other raw materials, proportions and preparation methods are the same as in Example 1.

[0085] Comparative Example 3 The difference from Example 1 is that only 100 parts of N,N-dibutyldithiocarbamate propionitrile, 15 parts of O-butyl-N-isobutylthiocarbamate, and 15 parts of xanthate (sodium isobutyl xanthate) are used. All raw materials are mixed evenly and an appropriate amount of water is added to make a paste.

[0086] Experimental Example Based on the above embodiments and comparative examples of the foaming agents, tests were conducted as follows.

[0087] (1) Emulsion stability: The foaming agent sample was sealed in a 100 mL graduated cylinder and left to stand at 25℃ for 30 days. The volume percentage of the layer (upper oil phase and lower water phase) was observed.

[0088] (2) Foaming property: Using a Roche foam apparatus, a 0.1% (based on the effective ingredient) aqueous solution was prepared, and the initial foam height (mm) and foam half-life (min) after 5 minutes were measured.

[0089] (3) Copper flotation experiment: A copper mine (raw ore Cu grade 0.75%, oxidation rate 8%, mud content 12%), grinding fineness -74μm accounted for 70%, XFD-1L flotation machine, rotation speed 1800rpm, aeration rate 0.2m³ / h, reagent dosage 300g / t, one roughing, to determine the copper concentrate grade and recovery rate.

[0090] The results are shown in Table 2: Table 2

[0091] From Table 2, we can conclude that In Examples 1-5, due to the presence of phosphonic acid-modified betaine and alcohol ether carboxylates, nanoemulsions were formed after high-pressure homogenization, showing no stratification after 30 days. Comparative Example 1: Ordinary betaine has slightly weaker emulsifying ability, resulting in slight stratification. Comparative Example 2: Unesterified polypropylene glycol ether has no surface activity and cannot stabilize the oil phase, resulting in obvious stratification. Comparative Example 3: Without any emulsifier, direct mixing resulted in rapid stratification; it must be prepared and used immediately.

[0092] Phosphate-esterified polypropylene glycol ether (Example) exhibits significantly better foaming ability than unesterified polyether (Comparative Example 2), with higher foam height and a moderate half-life, which is beneficial for mineral flotation. Modified betaine, containing phosphonic acid groups, does not affect foaming performance; on the contrary, it synergistically enhances foam stability with alcohol ether carboxylates.

[0093] Example 1: After flotation: Grade 18.5%, Recovery 92.3%. The modified betaine exhibits synergistic effects in resisting hard water, assisting collection, and inhibiting slime. Comparative Example 1: Ordinary betaine has weak resistance to hard water; some xanthate is precipitated by calcium and magnesium, reducing the recovery rate; it also lacks assisting collection, resulting in a lower grade. Comparative Example 2: Poor foaming, thin foam, low mineral loading, and a significantly reduced recovery rate; simultaneously, the lack of phosphate ester dispersion leads to severe slime interference. Comparative Example 3: Only collector without foaming agent; very little foam, flotation cannot proceed normally, relying mainly on natural mineralization, hence low recovery and grade.

[0094] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A copper flotation collector foaming agent, characterized in that, By weight, it includes the following ingredients: 100-120 parts of N,N-dibutyldithiocarbamate propionitrile, 12-18 parts of O-butyl-N-isobutylthiocarbamate, 12-18 parts of xanthate, 15-20 parts of phosphate-modified polypropylene glycol ether, 5-8 parts of modified betaine, 3-5 parts of alcohol ether, 1-3 parts of mud inhibitor, 2-5 parts of alcohol ether carboxylate, and 0.8-1.2 parts of sorbitan monooleate.

2. The copper flotation collector foaming agent according to claim 1, characterized in that, By weight, it includes the following ingredients: 100 parts of N,N-dibutyldithiocarbamate propionitrile, 15 parts of O-butyl-N-isobutylthiocarbamate, 15 parts of xanthate, 18 parts of phosphorylated polypropylene glycol ether, 7 parts of modified betaine, 4 parts of alcohol ether, 2 parts of mud inhibitor, 3 parts of alcohol ether carboxylate, and 1 part of dehydrated sorbitan monooleate.

3. The copper flotation collector foaming agent according to claim 1, characterized in that, The modified betaine is prepared by the following steps: Add cocoyl dimethyl tertiary amine to water and isopropanol, stir and heat to 50-60℃, add 10-15% NaOH aqueous solution dropwise, adjust the pH of the system to 9.0-9.5, and obtain the reaction solution; Dissolve 2-chloroethylphosphonic acid in water and adjust the pH to 7 with 10-15% NaOH to obtain the phosphoric acid reagent; Add phosphoric acid reagent dropwise to the reaction solution and stir at 60-65℃ for 6-8 hours, maintaining pH 8.5-9.0 during stirring. Cool the reaction system to room temperature, adjust the pH to 3-4, and evaporate by rotary evaporation to obtain a concentrated solution. Add anhydrous ethanol, heat to 50-55℃, stir for 30-40 minutes, hot filter, and evaporate the filtrate by rotary evaporation to obtain a paste. The paste was dissolved in water, and the pH was adjusted to 6.5-7.0 to obtain the modified betaine.

4. The copper flotation collector foaming agent according to claim 1, characterized in that, The alcohol ether is at least one of ethylene glycol tert-butyl ether, diethylene glycol tert-butyl ether, polypropylene glycol ether, ethylene glycol butyl ether, and propylene glycol ether.

5. The copper flotation collector foaming agent according to claim 1, characterized in that, The sludge inhibitor is at least one of sodium polyepoxysuccinate, polyaspartic acid, and carboxymethyl cellulose.

6. The copper flotation collector foaming agent according to claim 1, characterized in that, The xanthate is at least one of sodium isobutyl xanthate, sodium isoamyl xanthate, sodium ethyl xanthate, and sodium propyl xanthate.

7. A method for preparing a copper flotation collector foaming agent as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: N,N-dibutyldithiocarbamate propionitrile, O-butyl-N-isobutylthiocarbamate, xanthate, phosphorylated polypropylene glycol ether, alcohol ether, and sorbitan monooleate are added sequentially to a stirred reactor and stirred for 10-20 minutes at 20-40℃ and 200-500 rpm to obtain an oily premix. S2: Dissolve the modified betaine, alcohol ether carboxylate, and mud inhibitor in 3-5 times their weight of deionized water, stir well, and obtain an aqueous solution. S3: Add the aqueous solution of S2 to the oily premix of S1, and stir for 15-30 minutes at 25-35℃ and 300-600rpm to obtain a crude emulsion; S4: Process the crude emulsion of S3 in a high-pressure homogenizer 1-3 times to obtain a fine emulsion; S5: Heat-treat and mature the fine emulsion of S4 by stirring at 40-60℃ for 30-60 minutes; S6: Cool to room temperature, filter, and let stand to defoam, thus obtaining the foam-collecting agent.

8. The method for preparing the copper flotation collector foaming agent according to claim 7, characterized in that, In step S4, the pressure of high-pressure homogenization is 40-60 MPa, and the homogenization is performed twice.

9. The method for preparing the copper flotation collector foaming agent according to claim 7, characterized in that, In step S5, the heat treatment temperature is 45-55℃ and the time is 40-50 minutes.

10. The method for preparing the copper flotation collector foaming agent according to claim 7, characterized in that, In S1 and / or S3, pulsed ultrasound treatment is also applied, with a pulsed ultrasound frequency of 28-40 kHz, a power density of 0.3-0.8 W / mL, and a treatment time of 5-15 minutes.

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