Environment-friendly xanthate collecting agent and preparation method and application thereof

Abstract

The invention belongs to the technical field of mineral flotation, and particularly discloses an environment-friendly xanthate collecting agent and a preparation method and application thereof. The environment-friendly xanthate collecting agent comprises at least one of alkoxy dithiocarbonate as shown in formulas I-VII, wherein the alkoxy dithiocarbonate is selected from the group consisting of alkoxy dithiocarbonate as shown in the formulas I-VII; the preparation method of the environment-friendly xanthate collecting agent comprises the following steps that epoxypropane, fatty alcohol and caustic alkali A are added into a reaction kettle, an oxyalkylation ring-opening addition reaction is conducted under the inert atmosphere, and propylene glycol ether reaction liquid is obtained; and carbon disulfide and caustic alkali B are added into the propylene glycol ether reaction liquid for a reaction, and the environment-friendly xanthate collecting agent is obtained. The raw materials are wide in source, the cost is low, the yield is high, operation is easy and convenient, no waste water is discharged in the reaction process, and the obtained product is free of pungent smell, high in collecting performance, good in environmental compatibility and easy to degrade in an aqueous solution and has good industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of mineral flotation technology, and in particular to an environmentally friendly xanthate collector, its preparation method, and its application. Background Technology

[0002] Xanthates, scientifically known as dithiocarbonates, commonly called xanthates, have the general structural formula R-OCSSM, where R is usually a C2-C8 hydrocarbon group and M is Na or K. In 1925, Keller used xanthates as a flotation collector for non-ferrous metal sulfide ores, thus greatly promoting the development of mineral flotation technology. To this day, xanthates remain the most widely used and consumed sulfide ore collector.

[0003] Numerous studies have reported on the synthesis and structural modification of xanthates and their derivatives. Patent CN119306643A discloses a method of reacting alkali metals with isopropanol to generate isopropoxide, which is then reacted with carbon disulfide to generate diisopropyl xanthate, and subsequently reacted with sulfur and sulfur dichloride to synthesize diisopropyl xanthate tetrasulfide, used as a rubber additive. Patent CN112409280A discloses a method of reacting hexamethylolmelamine with caustic soda and carbon disulfide to prepare 2,4,6-(N-tetramethylxanthate sodium)-4,6-(N-dihydroxymethylamino)-1,3,5-triazine. Patent CN106380436A discloses a method for preparing diisopropyl disulfide xanthate using isopropanol, solid alkali, carbon disulfide, and chlorine as raw materials. Patent CN102463104A discloses a method for preparing clay-based xanthates by reacting alkali-treated clay with carbon disulfide. Patent CN113245066A discloses a method for preparing xanthate collectors by reacting polyalkoxy xanthates with halogenated compounds. Patent CN1138031A discloses the synthesis of 1,3-dimethylbutyl xanthate from methyl isobutyl methanol with alkali and carbon disulfide. Liao Wei reported that diethylamine methanol xanthate (structural formula shown in formula a below) has better flotation performance for stibnite than conventional xanthates (Liao Wei. Diethylamine methanol xanthate. Nonferrous metals (mineral processing section), 1991(6):27-28.). Han Qiaofeng et al. reported two aromatic xanthate compounds, sodium benzyl xanthate and sodium p-aminophenyl xanthate (structural formula shown in formula b), and studied their extraction performance (Han Qiaofeng, Fan Shulong, Yang Xujie, et al. Synthesis and extraction performance study of aromatic xanthates. Jiangsu Chemical Industry, 2002, 30(3):33-34.). Patent CN105601755A discloses a method for preparing a cellulose xanthate heavy metal scavenger. Patents US3711444 and US3965137 disclose xanthates and xanthate esters with specific structures (structural formulas shown in formulas c and d) and their applications in polymer synthesis.

[0004] (Formula a); (Formula b); (Formula c); (Equation d, where X is S or O).

[0005] Propylene glycol ethers contain alkyl, hydroxyl, and ether bonds, exhibiting the solvent properties of both alcohols and ethers. Their strong hydrogen bonding makes them highly efficient coupling agents between organic and aqueous phases. These solvents are known as "universal solvents" due to their mild odor, high solubility, and moderate evaporation rate, and are widely used in paints, inks, electronic chemicals, dyes, textiles, and leather. Commonly used industrial varieties include dipropylene glycol methyl ether, dipropylene glycol butyl ether, and propylene glycol n-butyl ether. Their hydrophobic-hydrophilic balance structure makes them an important class of fine chemical products. Currently, the main methods for synthesizing propylene glycol ethers include the Williamson synthesis, acetaldehyde method, alkoxypropylene oxide method, and propylene oxide method, among which the propylene oxide method is the most commonly used due to its mature technology and ease of industrialization. This method uses propylene oxide and the corresponding alcohol as raw materials, reacting them under the action of a catalyst to produce propylene glycol ethers. The choice of catalyst is crucial to the reaction, and they are mainly divided into acidic and basic types. Traditional homogeneous acid catalysts suffer from poor selectivity, severe equipment corrosion, high energy consumption, and heavy pollution, limiting their application. Alkaline catalysts such as caustic soda, alcohols, trimethylamine, and triethylamine exhibit high catalytic activity and good selectivity for primary ethers (primary ethers have low toxicity and excellent performance, making them ideal products), and the conversion rate of ethylene oxide can be increased by increasing the catalyst dosage. However, they generally suffer from the bottleneck of difficult catalyst-product separation.

[0006] Currently, the pungent odors generated during the production and use of traditional alkyl xanthates cause environmental pollution. With the increasing stringent environmental requirements for mineral processing reagents in China, the development of efficient and environmentally friendly novel collectors has become an urgent need for achieving green mineral flotation. It is worth noting that, to date, the synthesis process for preparing environmentally friendly xanthate collectors using propylene oxide as a raw material and co-producing propylene glycol ethers has not been reported in domestic or international literature or patents, indicating significant research value and application prospects. Summary of the Invention

[0007] In view of the above-mentioned problems, the present invention provides an environmentally friendly xanthate collector, its preparation method, and its application. The environmentally friendly xanthate collector of the present invention is odorless, easily degradable, has high yield, high purity, and is highly efficient in flotation of minerals. Furthermore, the method of the present invention can effectively improve the working environment of the production and use of the xanthate collector, does not cause pollution, is simple to operate, low in cost, and is easy to implement for industrial production.

[0008] To address the above problems, this invention provides an environmentally friendly xanthate collector.

[0009] Propylene oxide and fatty alcohol undergo an oxyalkylation ring-opening addition reaction under the catalysis of a caustic alkali, followed by the addition of carbon disulfide and a caustic alkali to produce an environmentally friendly xanthate collector.

[0010] Alternatively, propylene oxide and fatty alcohol can undergo an oxyalkylation ring-opening addition reaction under the catalysis of a caustic alkali. After recovering the unreacted propylene oxide, unreacted fatty alcohol and / or the generated propylene glycol monoether, carbon disulfide and a caustic alkali are added to carry out the reaction to obtain an environmentally friendly xanthate collector.

[0011] The environmentally friendly xanthate collector includes at least one alkoxy dithiocarbonate of formulas I to VII:

[0012] ;

[0013] Formula I;

[0014] ;

[0015] Formula II;

[0016] ;

[0017] Formula III;

[0018] ;

[0019] Formula IV;

[0020] ;

[0021] Formula V;

[0022] ;

[0023] Formula VI;

[0024] ;

[0025] Equation VII;

[0026] In formulas I to VII, R is selected from one of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec-pentyl, and neopentyl; M is Na or K.

[0027] Preferably, R is selected from one of methyl, ethyl, n-propyl, and n-butyl.

[0028] Based on the same inventive concept, the present invention also provides a method for preparing any of the above-mentioned environmentally friendly xanthate collectors, comprising the following steps:

[0029] S1. Add propylene oxide, fatty alcohol and caustic base A to a reaction vessel and carry out an oxygen alkylation ring-opening addition reaction under an inert atmosphere to obtain a propylene glycol ether reaction solution.

[0030] S2. Carbon disulfide and caustic alkali B are added to the propylene glycol ether reaction solution to carry out the reaction, thereby obtaining an environmentally friendly xanthate collector;

[0031] Alternatively, unreacted propylene oxide, unreacted fatty alcohols, and / or the generated propylene glycol monoether can be recovered, followed by the addition of carbon disulfide and caustic alkali B for reaction, to obtain an environmentally friendly xanthate collector.

[0032] Preferably, in step S1, the inert atmosphere is at least one of nitrogen, argon, and helium; the temperature of the oxygen alkylation ring-opening addition reaction is 50-140°C, and the time is 1-5 h; in step S2, the temperature of adding carbon disulfide and caustic alkali B for the reaction is 5-50°C, and the reaction time is 0.5-8 h.

[0033] Preferably, in step S1, the molar ratio of propylene oxide to fatty alcohol is 1.0:0.3-1.0:6.0; and the molar ratio of propylene oxide to caustic alkali is 1.0:0.002-1.0:0.5.

[0034] Preferably, in step S2, the molar ratio of carbon disulfide to fatty alcohol is 12.0:1.0-0.2:1.0; and the molar ratio of caustic alkali B to fatty alcohol is 1.2:1.0-0.5:1.0.

[0035] Based on the same inventive concept, the present invention also provides the application of the above-mentioned environmentally friendly xanthate collector or the environmentally friendly xanthate collector prepared by the above preparation method in mineral flotation.

[0036] Preferably, the mineral includes at least one of copper sulfide ore, lead-zinc ore, pyrite, nickel sulfide ore, and copper-molybdenum ore.

[0037] Preferably, the amount of the environmentally friendly xanthate collector is 10-150 g / t, and the pH value of the slurry is 4-13.

[0038] In the preparation process of the environmentally friendly xanthate collector of the present invention, propylene oxide and fatty alcohol react under the action of a catalyst to obtain propylene glycol ether products (including propylene glycol monoether, dipropylene glycol ether, tripropylene glycol ether, tetrapropylene glycol ether, etc.). The propylene glycol ether products react with carbon disulfide and caustic alkali (NaOH or KOH or a mixture of both) to generate alkoxydithiocarbonates. The chemical reaction formulas I to VII are listed below (formulas I to VI are obtained by reacting propylene glycol ether products with carbon disulfide and caustic alkali; formula VII is obtained by reacting unreacted fatty alcohol with carbon disulfide and caustic alkali):

[0039] ;

[0040] ;

[0041] ;

[0042] ;

[0043] ;

[0044] ;

[0045] .

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] (1) The environmentally friendly alkoxydithiocarbonate collector provided by this invention has strong collecting ability and good selectivity. It requires a low dosage in practical applications and is particularly suitable for the flotation separation of various sulfide minerals such as copper sulfide ore, nickel sulfide ore, copper-molybdenum ore, pyrite, and lead-zinc ore. In addition, this collector can be used in combination with common collectors such as xanthate, thiocyanate, and thiocyanate to further improve flotation indicators and provide a new technical path for the separation of complex minerals.

[0048] (2) Compared with traditional alkyl xanthate collectors, environmentally friendly alkoxy dithiocarbonate collectors have no irritating odor, effectively avoiding pollution of the production and use environment by irritating odors. At the same time, the agent is easily degraded in the aqueous phase, which helps to recycle mineral processing wastewater and significantly improves the environmental friendliness of the agent in the production and use process;

[0049] (3) This invention uses widely available and low-cost propylene oxide as the main raw material and caustic alkali (sodium hydroxide or potassium hydroxide) as the catalyst, which not only has high reaction efficiency and good selectivity, but also effectively reduces energy consumption. After the reaction, there is no need to separate and recover the unreacted caustic alkali. Only simple distillation is needed to recover the unreacted propylene oxide and fatty alcohol (not recovering will not affect the harvesting effect, but the economic cost is high), and high-purity propylene glycol monoether products can be obtained at the same time. Adding an appropriate amount of caustic alkali and carbon disulfide to the distillation residue can further react to generate the target product alkoxy dithiocarbonate. This process route simplifies the operation process, reduces production costs, and solves the problems of corrosion of equipment by traditional acid catalysts and difficulty in separating alkali catalysts in the industrial production of propylene glycol ether using the propylene oxide method.

[0050] (4) The intermediate products generated during the reaction process of the preparation method provided by the present invention include propylene glycol monoether, dipropylene glycol monoether and other ether alcohols, which are heteropolar surfactants with polar and nonpolar structures and have certain foaming or collecting properties. Even if they are not completely converted in the subsequent xanthate reaction and remain in the final product, they can still have a positive synergistic effect on the flotation process and improve the flotation effect;

[0051] (5) The preparation method provided by the present invention can effectively adjust the relative content of each component in formula (I)-(VII) in the final product by controlling the feeding ratio of propylene oxide and fatty alcohol in the initial raw materials, thereby achieving precise control of the product flotation performance and meeting the flotation requirements of different mineral systems.

[0052] (6) The preparation method provided by the present invention not only solves the problem of catalyst separation difficulty in the traditional propylene glycol ether synthesis process by co-producing propylene glycol monoether products, but also significantly reduces the production cost of propylene glycol ether and improves the overall economic benefits of the process.

[0053] (7) The collector prepared by the present invention has high purity and yield, low impurity content, simple process flow, good environmental compatibility, and good prospects for industrial promotion. Attached Figure Description

[0054] Figure 1 The ultraviolet spectrum of O-(1-methyl-2-methoxy)dithiocarbonate prepared in Comparative Example 1 of this invention is shown.

[0055] Figure 2 The potassium O-(1-methyl-2-methoxy)dithiocarbonate prepared in Comparative Example 1 of this invention 1 H NMR spectrum;

[0056] Figure 3 The potassium O-(1-methyl-2-methoxy)dithiocarbonate prepared in Comparative Example 1 of this invention 13 C NMR spectrum;

[0057] Figure 4 The ultraviolet spectrum of O-(1-methyl-2-ethoxy)dithiocarbonate prepared in Comparative Example 2 of this invention is shown.

[0058] Figure 5 The infrared spectrum of O-(1-methyl-2-ethoxy)dithiocarbonate prepared in Comparative Example 2 of this invention is shown.

[0059] Figure 6 The O-(1-methyl-2-ethoxy)dithiocarbonate prepared in Comparative Example 2 of this invention 1 H NMR spectrum;

[0060] Figure 7 The O-(1-methyl-2-ethoxy)dithiocarbonate prepared in Comparative Example 2 of this invention 13 C NMR spectrum;

[0061] Figure 8 The ultraviolet spectrum of O-(1-methyl-2-butoxy)dithiocarbonate prepared in Comparative Example 3 of this invention is shown.

[0062] Figure 9 The potassium O-(1-methyl-2-butoxy)dithiocarbonate prepared in Comparative Example 3 of this invention 1 H NMR spectrum;

[0063] Figure 10 The O-(1-methyl-2-butoxy)dithiocarbonate prepared in Comparative Example 3 of this invention 13 C NMR spectrum;

[0064] Figure 11 This is a flowchart of a single mineral flotation process;

[0065] Figure 12 The flotation recovery rates of lead ore and sphalerite are shown below for the final products of Examples 1, 2, and 4 of this invention.

[0066] Figure 13 The flotation recovery rates of chalcopyrite and pyrite under the dosage of the final products of Examples 5, 3, and 4 of this invention;

[0067] Figure 14 The above is a flotation process diagram of the products of Example 5 and Comparative Example 4 of this invention for the actual flotation of a copper sulfide ore. Detailed Implementation

[0068] To make the present invention easier to understand, specific embodiments are described below to further illustrate the invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art; unless otherwise specified, the raw materials and reagents involved herein can be purchased commercially or obtained by known methods.

[0069] It should be noted that the “yield” in the embodiments of this application means: mass of reaction product / mass of theoretical target product × 100.

[0070] It should be noted that the number of parts added for each raw material in the embodiments of this application are all parts by mass.

[0071] To address the problems existing in the background technology, the present invention provides an environmentally friendly xanthate collector, its preparation method, and its application.

[0072] The following examples and comparative models further illustrate this point.

[0073] Example 1: Synthesis of an environmentally friendly xanthate collector using propylene glycol monoethyl ether reaction solution as raw material

[0074] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 46.1 parts of anhydrous ethanol, 58.1 parts of propylene oxide, and 1.0 part of potassium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 80-85°C and stirred for 3.0 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol monoethyl ether reaction solution. The propylene glycol monoethyl ether reaction solution was transferred to a three-necked flask, and 429.2 parts of carbon disulfide and 61.4 parts of potassium hydroxide were added. The mixture was stirred at 25°C for 4 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 206.6 parts of a pale yellow, environmentally friendly xanthate collector product, with a yield of 94.06%.

[0075] Example 2: After distilling and recovering ethanol and 90% propylene glycol ethyl ether from the reaction product of propylene glycol monoethyl ether, an environmentally friendly xanthate collector was synthesized using the distillate as a raw material.

[0076] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 36.9 parts of anhydrous ethanol, 58.1 parts of propylene oxide, and 1.2 parts of potassium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 75-80°C for 4.5 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol monoethyl ether reaction solution. The propylene glycol monoethyl ether reaction solution was transferred to a still, and unreacted ethanol was recovered by distillation at 77-79°C. The temperature was then increased to 132-133°C for further recovery, yielding 41.2 parts of propylene glycol monoethyl ether, with a purity of 99.5%. After distillation, the distillate was transferred to a three-necked flask, and 126.5 parts of carbon disulfide and 17.1 parts of potassium hydroxide were added. The mixture was stirred at 25°C for 6 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 82.3 parts of a yellow powdery environmentally friendly xanthate collector with a yield of 93.37%.

[0077] Example 3: Synthesis of an environmentally friendly xanthate collector using propylene glycol monobutyl ether synthesis reaction solution as raw material

[0078] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 74.1 parts of n-butanol, 116.2 parts of propylene oxide, and 2.6 parts of potassium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 75-80°C for 4.5 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol butyl ether reaction solution. The propylene glycol butyl ether reaction solution was transferred to a three-necked flask, and 478.8 parts of carbon disulfide and 56.2 parts of potassium hydroxide were added. The mixture was stirred at 25°C for 4 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 314.28 parts of a pale yellow, environmentally friendly xanthate collector product, with a yield of 95.56%.

[0079] The components of the above-mentioned propylene glycol butyl ether reaction solution are: n-butanol 2.94wt%, propylene glycol butyl ether 32.86wt%, dipropylene glycol butyl ether 34.20wt%, tripropylene glycol butyl ether 19.10wt%, tetrapropylene glycol butyl ether 5.32wt%, and other heavy components 5.58wt%.

[0080] Example 4: Synthesis of an environmentally friendly xanthate collector using propylene glycol monobutyl ether synthesis reaction solution as raw material

[0081] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 74.1 parts of n-butanol, 58.1 parts of propylene oxide, and 1.3 parts of potassium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 75-80°C for 4.5 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol butyl ether reaction solution. The propylene glycol butyl ether reaction solution was transferred to a three-necked flask, and 456.8 parts of carbon disulfide and 64.7 parts of potassium hydroxide were added. The mixture was stirred at 25°C for 4 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 257.5 parts of a pale yellow, environmentally friendly xanthate collector product, with a yield of 93.85%.

[0082] The components of the above-mentioned propylene glycol butyl ether reaction solution are: n-butanol 20.62wt%, propylene glycol butyl ether 52.25wt%, dipropylene glycol butyl ether 21.18wt%, tripropylene glycol butyl ether 4.97wt%, tetrapropylene glycol butyl ether 0.79wt%, and other heavy components 0.19wt%.

[0083] Example 5: The reaction product for the synthesis of propylene glycol monobutyl ether was used to synthesize an environmentally friendly xanthate collector after distillation to recover n-butanol and 90% propylene glycol monobutyl ether.

[0084] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 60.0 parts of n-butanol, 58.1 parts of propylene oxide, and 9.4 parts of potassium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 75-80℃ for 4.5 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol monobutyl ether reaction solution. The propylene glycol monobutyl ether reaction solution was transferred to a distiller and distilled at 117-118℃ to recover unreacted n-butanol. The temperature was then increased to 170-171℃ for further recovery, yielding 51.4 parts of propylene glycol monobutyl ether, with a purity of 99.5%. After distillation, the distillate was transferred to a three-necked flask, and 114.2 parts of carbon disulfide and 7.1 parts of potassium hydroxide were added. The mixture was stirred at 25°C for 4 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 80.87 parts of a yellow powdery environmentally friendly xanthate collector with a yield of 91.56%.

[0085] The components of the above-mentioned propylene glycol monobutyl ether reaction solution are: n-butanol 12.32wt%, propylene glycol butyl ether 48.27wt%, dipropylene glycol butyl ether 29.13wt%, tripropylene glycol butyl ether 8.27wt%, tetrapropylene glycol butyl ether 1.43wt%, and other heavy components 0.58wt%.

[0086] Example 6: The reaction product for the synthesis of propylene glycol monobutyl ether was used to recover n-butanol by distillation, and the distillate was then used as a raw material to synthesize an environmentally friendly xanthate collector.

[0087] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 185.3 parts of n-butanol, 58.1 parts of propylene oxide, and 18.7 parts of potassium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 75-80°C for 4.5 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol monobutyl ether reaction solution. The propylene glycol monobutyl ether reaction solution was transferred to a still, and 110.7 parts of unreacted n-butanol were recovered by distillation. After distillation, the distillate was transferred to a three-necked flask, and 466.0 parts of carbon disulfide and 48.6 parts of potassium hydroxide were added. The mixture was stirred at 25°C for 4 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 264.2 parts of a yellow, powdery, environmentally friendly xanthate collector product, with a yield of 95.14%.

[0088] The components of the above-mentioned propylene glycol monobutyl ether reaction solution are: n-butanol 51.48wt%, propylene glycol butyl ether 42.54wt%, dipropylene glycol butyl ether 5.20wt%, tripropylene glycol butyl ether 0.25wt%, and other heavy components 0.53wt%.

[0089] Example 7: The reaction product for the synthesis of propylene glycol monomethyl ether was distilled to recover methanol, and the distillate was used as a raw material to synthesize an environmentally friendly xanthate collector.

[0090] The reaction was carried out in a 1L stainless steel autoclave equipped with a stirrer. Before the reaction, the entire apparatus was purged with nitrogen. Then, 32.0 parts of methanol, 58.1 parts of propylene oxide, and 5.0 parts of sodium hydroxide were accurately weighed and added to the autoclave. After purging with nitrogen to maintain the predetermined initial pressure, stirring was started and the mixture was rapidly heated to 75-80°C for 4.5 hours. After the reaction, the mixture was cooled with cooling water to obtain a propylene glycol monomethyl ether reaction solution. The propylene glycol monomethyl ether reaction solution was transferred to a still and distilled at 64-65°C to recover 9.1 parts of unreacted methanol. After distillation, the distillate was transferred to a three-necked flask, and 266.5 parts of carbon disulfide and 24.2 parts of sodium hydroxide were added. The mixture was stirred at 25°C for 3 hours. The carbon disulfide solvent was recovered by vacuum distillation, yielding 170.17 parts of a light yellow, powdery, environmentally friendly xanthate collector product, with a yield of 97.96%.

[0091] Comparative Example 1: O-(1-methyl-2-methoxy)potassium dithiocarbonate ( Preparation of )

[0092] 9.10 parts of propylene glycol methyl ether and 38.45 parts of carbon disulfide were added to a three-necked flask. Then, 6.93 parts of granular potassium hydroxide were added in three batches at 10°C with mechanical stirring. After the addition was complete, the temperature was raised to 20°C and the reaction was carried out for 5 hours. 20.82 parts of a light yellow powdery xanthate collector with a purity of 92.39% were obtained, with a yield of 94.70%.

[0093] The product was characterized after multiple recrystallization purifications. The ultraviolet spectrum of O-(1-methyl-2-methoxy)dithiocarbonate is as follows: Figure 1 As shown, the maximum absorption wavelength is at 302 nm, while a small peak appears at 228 nm.

[0094] O-(1-methyl-2-methoxy)dithiocarbonate potassium 1 In the H NMR spectrum, as shown Figure 2 As shown, the chemical shifts of each proton and their assignments are as follows: 400MHz 1 H NMR (DMSO-d6): δ 1.13 (3H, CH3), 3.26 (3H, CH3), 3.32 (1H, CH2), 3.45 (1H, CH2), 5.56 (1H, CH).

[0095] O-(1-methyl-2-methoxy)dithiocarbonate potassium 13 C NMR (DMSO-d6) such as Figure 3As shown, δ 17.37(CH3), 58.77(CH3), 74.62(CH2), 75.18(CH2), 75.18(CH).

[0096] Comparative Example 2: O-(1-methyl-2-ethoxy)potassium dithiocarbonate ( Preparation of )

[0097] 10.52 parts of propylene glycol ethyl ether and 61.53 parts of carbon disulfide were added to a three-necked flask. Then, 6.93 parts of granular potassium hydroxide were added in three batches at 10°C with mechanical stirring. After the addition was complete, the temperature was raised to 20°C and the reaction was carried out for 5 hours. 23.24 parts of a pale yellow powdery xanthate collector with a purity of 93.93% were obtained, representing a yield of 92.34%.

[0098] The product was characterized after multiple recrystallization purifications. The UV spectrum of O-(1-methyl-2-ethoxy)dithiocarbonate is as follows: Figure 4 As shown, the maximum absorption wavelength is at 302 nm, while a small peak appears at 228 nm.

[0099] The infrared spectrum of O-(1-methyl-2-ethoxy)dithiocarbonate is as follows: Figure 5 As shown, its main characteristic peaks include (cm) -1 Peaks 2975, 2933, 2894, and 2862 are attributed to the stretching vibrations of CH3 and CH2; peaks 1447 and 1385 are attributed to the deformation vibrations of CH3; peak 1131 is attributed to the stretching vibration of COC; peak 1051 is attributed to the absorption peak of SC=S; and peak 969 is attributed to the stretching vibration of CS.

[0100] O-(1-methyl-2-ethoxy)dithiocarbonate potassium 1 In the H NMR spectrum, as shown Figure 6 As shown, the chemical shifts of each proton and their assignments are as follows: 400 MHz 1 H NMR (DMSO-d6): δ 1.11 (3H, CH3), 1.15 (3H, CH3), 3.33 (1.2H, CH2), 3.45 (2H, CH2), 3.50 (0.8H, CH2), 5.54 (1H, CH).

[0101] O-(1-methyl-2-ethoxy)dithiocarbonate potassium 13 C NMR (DMSO-d6) such as Figure 7 As shown, δ 15.63 (CH3), 17.48 (CH3), 66.15 (CH2), 73.09 (CH2), 74.82 (CH), 229.71 (C=S).

[0102] Comparative Example 3: O-(1-methyl-2-butoxy)potassium dithiocarbonate ( Preparation of )

[0103] 6.68 parts of propylene glycol butyl ether and 30.76 parts of carbon disulfide were added to a three-necked flask. Then, 3.47 parts of granular potassium hydroxide were added in three batches at 15°C with mechanical stirring. After the addition was complete, the temperature was raised to 20°C and the reaction was carried out for 5 hours. 13.60 parts of an orange-yellow, blocky xanthate collector with a purity of 84.83% were obtained, with a yield of 87.26%.

[0104] The product was characterized after multiple recrystallization purifications. The UV spectrum of O-(1-methyl-2-butoxy)dithiocarbonate is as follows: Figure 8 As shown, the maximum absorption wavelength is at 302 nm, while a small peak appears at 228 nm.

[0105] O-(1-methyl-2-butoxy)dithiocarbonate potassium 1 In the H NMR spectrum, as shown Figure 9 As shown, the chemical shifts of each proton and their assignments are as follows: 400 MHz 1 H NMR (DMSO-d6): δ 0.88 (3H, CH3), 1.15 (3H, CH3), 1.33 (2H, CH2), 1.48 (2H, CH2), 3.32 (1H, CH2), 3.40 (2H, CH2), 3.50 (0.8H, CH2), 5.54 (1H, CH2).

[0106] O-(1-methyl-2-ethoxy)dithiocarbonate potassium 13 C NMR (DMSO-d6) such as Figure 10 As shown, δ 14.25 (1C, CH3), 17.45 (2C, CH3), 19.30 (1C, CH2), 31.79 (1C, CH2), 70.60 (1C, CH), 73.25 (1C, CH2), 74.84 (1C, CH), 229.81 (C=S).

[0107] Comparative Example 4

[0108] Commercially available sodium isobutyl dithiocarbonate (85% purity).

[0109] Performance testing and results analysis:

[0110] The harvesting capacity of the final products from Examples 1, 2, and 4 for galena and sphalerite was tested:

[0111] according to Figure 11 The flotation process was carried out by adding the final products (as collectors) of Example 1, Comparative Example 2, and Comparative Example 4, respectively. Galena and sphalerite were flotated for 3 minutes, with a pulp pH of 8. The amounts of the products from Example 1, Comparative Example 2 (O-(1-methyl-2-ethoxy) potassium dithiocarbonate), and Comparative Example 4 (commercially available sodium isobutyl dithiocarbonate, effective amount) were 0-10 × 10⁻⁶. –5 mol / L, flotation results are as follows Figure 12 As shown, by Figure 12 It can be seen that the dosage in the product of Example 1 is 2 × 10 –5 At a concentration of mol / L, the recoveries of galena and sphalerite were 92.64% and 3.68%, respectively. The amount of O-(1-methyl-2-ethoxy)dithiocarbonate used in Comparative Example 2 was 2 × 10⁻⁶ mol / L. –5 At mol / L, the recoveries of galena and sphalerite were 91.44% and 3.19%, respectively. Comparative Example 4, commercially available sodium isobutyl dithiocarbonate, showed recoveries of 2 × 10⁻⁶ mol / L. –5 The recoveries of galvanite and sphalerite at a dosage of mol / L were 75.17% and 15.53%, respectively. This indicates that, as shown in Example 1 and Comparative Example 2, the xanthate collector directly synthesized from propylene glycol monoethyl ether reaction solution has a stronger collecting ability for galvanite than the O-(1-methyl-2-ethoxy)dithiocarbonate synthesized from propylene glycol monoethyl ether alone. This suggests that the incompletely reacted raw materials and intermediate products in the propylene glycol monoethyl ether reaction solution enhance the selective collection of galvanite. As shown in Comparative Examples 2 and 4, the O-(1-methyl-2-ethoxy)dithiocarbonate of the present invention has a much better collecting ability and selectivity for galvanite than commercially available isobutyl dithiocarbonate.

[0112] The harvesting capacity of the final products from Example 5, Comparative Example 3, and Comparative Example 4 for chalcopyrite and pyrite was tested:

[0113] according to Figure 11 The flotation process was carried out by adding the final products (as collectors) of Example 5, Comparative Example 3, and Comparative Example 4, respectively. Chalcopyrite and pyrite were flotated for 3 minutes, with the pulp pH value being 8. The amounts of the products from Example 5, Comparative Example 3 (O-(1-methyl-2-butoxy) dithiocarbonate), and Comparative Example 4 (commercially available sodium isobutyl dithiocarbonate, effective amount) were 0-10 × 10⁻⁶. –5 mol / L, flotation results are as follows Figure 13 As shown, by Figure 13 It can be seen that the dosage of the product in Example 5 is 2 × 10⁻⁶. –5 At a concentration of mol / L, the recoveries of chalcopyrite and pyrite were 91.04% and 12.97%, respectively. The amount of O-(1-methyl-2-butoxy)dithiocarbonate used in Comparative Example 3 was 2 × 10⁻⁶ mol / L. –5At mol / L, the recoveries of chalcopyrite and pyrite were 87.12% and 12.26%, respectively. Comparative Example 4, commercially available sodium isobutyl dithiocarbonate, showed recoveries of 2 × 10⁻⁶ mol / L. –5 At a dosage of mol / L, the recoveries of chalcopyrite and pyrite were 75.17% and 15.53%, respectively. This indicates that, as shown by the comparison between Example 5 and Comparative Example 3, the xanthate collector directly synthesized from propylene glycol monobutyl ether reactor liquid has a stronger collecting ability than the O-(1-methyl-2-butoxy)dithiocarbonate potassium synthesized from propylene glycol monoethyl ether alone. This suggests that the xanthate collector obtained by xanthation of polyether alcohols such as dipropylene glycol butyl ether and tripropylene glycol butyl ether in the propylene glycol monobutyl ether reactor liquid, as well as its unreacted portion, can act as a foaming agent, enhancing the selective collection of chalcopyrite. As shown by Comparative Examples 3 and 4, the O-(1-methyl-2-butoxy)dithiocarbonate potassium of the present invention has a better collecting ability and selectivity for chalcopyrite than commercially available isobutyl dithiocarbonate sodium.

[0114] The products of Example 5 and Comparative Example 4 were subjected to flotation of a copper sulfide ore:

[0115] The ore sample is from a copper mine in Yunnan Province. The raw ore contains 0.47% copper and 0.87% sulfur. The following method is used: Figure 14 The process involves a roughing process. For each experiment, 500g of ore powder, 300mL of water, and a certain amount of lime are added to a ball mill and ground until the mineral particle size meets the requirements for beneficiation. The slurry is then transferred to a 1.5L single-cell flotation machine for flotation experiments. The flotation machine is started and stirred for 3 minutes, then a collector is added and stirred for another 3 minutes. A frother is then added and stirred for another 1 minute. The foam is collected for 5 minutes as the concentrate, and the product in the water tank is the tailings. After the concentrate is thoroughly dried, it is ground, samples are prepared, and the copper content is analyzed. The yield and recovery rate are calculated. The reagent formulation was as follows: grinding fineness was -200 mesh (66%), lime dosage was 400 g / t, frother was No. 2 oil (24 g / t), and collectors were the environmentally friendly xanthate collector product prepared in Example 5 and the commercially available sodium isobutyl dithiocarbonate product (85.0% purity) in Comparative Example 4 (the dosage of the product in Example 5 was the same as that of the commercially available sodium isobutyl dithiocarbonate product in Comparative Example 2 × 85.0%, both being 32 g / t). Other flotation test conditions and results are shown in Table 1.

[0116] Table 1. Flotation test results of the products from Example 5 and Comparative Example 4 on a copper sulfide ore collector.

[0117]

[0118] As shown in Table 1, the product prepared in Example 5 of this invention has a higher flotation recovery rate for copper sulfide ore and a higher copper concentrate grade than the commercially available sodium isobutyl dithiocarbonate collector in Comparative Example 4 by 6.39 and 0.33 percentage points, respectively. This indicates that the environmentally friendly xanthate collector product prepared in Example 5 has better flotation performance than sodium isobutyl dithiocarbonate. In other words, the environmentally friendly xanthate collectors containing alkoxy dithiocarbonates in formulas I-VII all have better flotation performance than sodium isobutyl dithiocarbonate.

[0119] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An environmentally friendly xanthate collector, characterized in that, Propylene oxide and fatty alcohol undergo an oxyalkylation ring-opening addition reaction under the catalysis of a caustic alkali, followed by the addition of carbon disulfide and a caustic alkali to produce an environmentally friendly xanthate collector. Alternatively, propylene oxide can undergo an oxyalkylation ring-opening addition reaction with a fatty alcohol under caustic alkali catalysis. After recovering unreacted propylene oxide, unreacted fatty alcohol, and / or the generated propylene glycol monoether, carbon disulfide and a caustic alkali are added for further reaction to obtain an environmentally friendly xanthate collector. The environmentally friendly xanthate collector includes at least one alkoxydithiocarbonate of formulas I to VII. ； Formula I; ； Formula II; ； Formula III; ； Formula IV; ； Formula V; ； Formula VI; ； Equation VII; In formulas I to VII, R is selected from one of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec-pentyl, and neopentyl; M is Na or K.

2. The environmentally friendly xanthate collector according to claim 1, characterized in that, The R is selected from one of methyl, ethyl, n-propyl, and n-butyl.

3. The method for preparing the environmentally friendly xanthate collector according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Add propylene oxide, fatty alcohol and caustic base A to a reaction vessel and carry out an oxygen alkylation ring-opening addition reaction under an inert atmosphere to obtain a propylene glycol ether reaction solution. S2. Carbon disulfide and caustic alkali B are added to the propylene glycol ether reaction solution to carry out the reaction, thereby obtaining an environmentally friendly xanthate collector; Alternatively, unreacted propylene oxide, unreacted fatty alcohols, and / or the generated propylene glycol monoether can be recovered, followed by the addition of carbon disulfide and caustic alkali B for reaction, to obtain an environmentally friendly xanthate collector.

4. The preparation method of the environmentally friendly xanthate collector according to claim 3, characterized in that, In step S1, the inert atmosphere is at least one of nitrogen, argon, and helium; the temperature of the oxygen alkylation ring-opening addition reaction is 50-140℃, and the time is 1-5h; in step S2, the temperature of adding carbon disulfide and caustic alkali B for the reaction is 5-50℃, and the reaction time is 0.5-8h.

5. The method for preparing the environmentally friendly xanthate collector according to claim 3, characterized in that, In step S1, the molar ratio of propylene oxide to fatty alcohol is 1.0:0.2-1.0:8.0; the molar ratio of propylene oxide to caustic alkali is 1:0.002-1:0.

5.

6. The method for preparing the environmentally friendly xanthate collector according to claim 3, characterized in that, In step S2, the molar ratio of carbon disulfide to fatty alcohol is 12.0:1.0-0.2:1.0; the molar ratio of caustic alkali B to fatty alcohol is 1.2:1.0-0.5:1.

0.

7. The application of the environmentally friendly xanthate collector according to any one of claims 1-2 or the environmentally friendly xanthate collector prepared by any one of claims 3-6 in mineral flotation.

8. The application according to claim 7, characterized in that, The minerals include at least one of copper sulfide ore, lead-zinc ore, pyrite, nickel sulfide ore, and copper-molybdenum ore.

9. The application according to claim 7, characterized in that, The dosage of the environmentally friendly xanthate collector is 10-150 g / t, and the pH value of the slurry is 4-13.

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