Dithiocarbonate collecting agent, preparation method thereof and application of dithiocarbonate collecting agent in metal ore flotation

Abstract

The invention belongs to the field of flotation, and particularly relates to a dithiocarbonate collecting agent, a preparation method of the dithiocarbonate collecting agent and application of the dithiocarbonate collecting agent in metal ore flotation. According to the collecting agent, molecular association can be promoted through intermolecular water bridging hydrogen bonds and the pi-pi accumulation effect, molecular volatilization is inhibited, and the peculiar foul smell of traditional xanthate is weakened or even eliminated from the source; meanwhile, introduction of N atoms with high electronegativity and pi-rich electron benzene rings in the molecular structure can synergistically regulate and control the electronic characteristics and the spatial configuration of collector molecules, and then selective collection of the collector on target minerals is enhanced.

Description

Technical Field

[0001] This invention relates to the field of mineral flotation technology, specifically to the field of metal ore collectors. Background Technology

[0002] The general structural formula for dithiocarbonate collectors (xanthate collectors) is ROCSSMe, where R is a hydrophobic chain and Me is usually Na or K. Due to their strong chelating ability with metal ions such as copper, iron, lead, and zinc, they possess collecting power for various sulfide minerals and are currently the most widely used and consumed sulfide mineral collectors. However, increasingly stringent environmental policies in recent years have placed enormous pressure on the production and application of traditional alkyl xanthates, which have a pungent odor.

[0003] Various strategies have been explored to address the odor problem of xanthates, including granulation, the addition of masking agents, and the design of novel xanthate products. While granulation and masking can reduce odor to some extent, they do not eliminate the pungent odor of xanthate molecules at their source. Conversely, molecular design that enhances intermolecular interactions by introducing specific functional groups or heteroatoms can effectively suppress volatility and provide a more sustainable solution. Patent document CN113042217A discloses an amide-based xanthate that eliminates odor and enhances the adsorption of xanthate collectors at mineral interfaces through a conjugated system between ligands and intermolecular hydrogen bonding. Furthermore, patent document CN109225647A discloses tert-butoxyethyl dithiocarbonate, its preparation method, and applications. Specifically, it describes how forming a water-bridged hydrogen bond network between ether oxygen atoms and water molecules to enhance intermolecular forces and suppress molecular volatility is also considered a feasible strategy.

[0004] However, the introduction of strongly hydrophilic amide and ether groups into the aforementioned novel xanthates results in a partial loss of hydrophobicity in the hydrophobic chain, necessitating the introduction of longer hydrophobic carbon chains for compensation. This leads to high raw material costs, limiting their industrial application. Therefore, there is an urgent need to design a molecular modification scheme that enhances intermolecular forces to suppress molecular volatilization without sacrificing hydrophobicity, and to develop a xanthate collector with low odor and excellent flotation performance based on this scheme. Summary of the Invention

[0005] In view of the problems of foul odor and poor selectivity of existing dithiocarbonate collectors, this invention provides a novel dithiocarbonate collector with low odor, its preparation method and application, aiming to provide a green and efficient flotation reagent.

[0006] A dithiocarbonate collector is a compound having the structural formula 1. Formula 1; Where Me is Na, K or NH4; R1 is a C1-C8 alkyl group or an alkyl group with a substituent; R2 is a C1-C8 alkylene group or an alkylene group with a substituent; The substituent is at least one selected from halogen, hydroxyl, alkyl, alkoxy, and phenyl.

[0007] This invention provides a collector with a novel structure that introduces a secondary nitrogen with a benzyl group at the oxygen end of dithiocarbonate, thereby controlling odor during synthesis and storage. Furthermore, it can enhance the collection rate and selectivity of metal ores based on the synergistic effect of molecular structure.

[0008] Alternatively, R1 can be a C1-C8 alkyl or benzyl group. R2 can be methylene, 1,2-ethylene, or 1,3-propylene.

[0009] As an optional solution, the dithiocarbonate collector is at least one of Formula 1A, Formula 1B, and Formula 1C. Formula 1A Formula 1B Formula 1C.

[0010] Further preferably, the collector comprises Formula 1A. Research in this invention shows that, thanks to the synergistic effect of the unique electronic structure and molecular configuration of Formula 1A, it can simultaneously eliminate odors and improve flotation performance.

[0011] The present invention also provides a method for preparing the dithiocarbonate collector, wherein the raw material of Formula 2 is subjected to a xanthation reaction with carbon disulfide and MeOH to obtain the product of Formula 1; Formula 2; The selection ranges of R1 and R2 in Equation 2 are the same as those in Equation 1; The range of Me selected in MeOH is the same as in Equation 1.

[0012] The synthesis reaction equation in the preparation method of this invention is as follows:

[0013] The solvent for the xanthation reaction is at least one of water, carbon disulfide, dichloromethane, tetrahydrofuran, and dichloroethane.

[0014] Formula 2, the molar ratio of MeOH and carbon disulfide is 1.0:1~2:1.0~10.0; preferably 1.0:1.1~1.5:4.0~8.0.

[0015] The temperature for xanthation is 0~40°C. oC can be room temperature, for example, 20~30℃, and the time can be reasonably controlled according to the reaction, for example, 0.5~8 h, or even 3~5 h.

[0016] The present invention also provides an application of the collector of Formula 1, which is used as a collector for the flotation of metal sulfide ores.

[0017] The collector described in this invention, thanks to the synergistic effect of its intramolecular structure, can enhance the collection ability and selectivity of the target ore.

[0018] Furthermore, the metal sulfide minerals include at least one of chalcopyrite, nickel pyrite, pyrite, galena, sphalerite, molybdenite, and gold and silver-bearing sulfide minerals.

[0019] As an optional application, the collector described in this invention can be used to selectively collect chalcopyrite from a mixed ore containing chalcopyrite and pyrite.

[0020] The present invention demonstrates that the collector of Formula 1 has excellent collecting ability and selectivity for chalcopyrite.

[0021] Furthermore, the dosage of the collector of Formula 1 is 5~400 g / t, and can be further 20~50 g / t.

[0022] In the flotation process of this invention, the pH of the pulp is 4-13, and can be further 9-12.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The collector provided by this invention constructs a Y-shaped or umbrella-shaped molecular structure by introducing a tertiary amine nitrogen (N) atom and a π-electron-rich benzene ring into the alkyl chain. Studies have shown that, thanks to the synergistic effect of the unique electronic structure and molecular configuration of this collector molecule, it can simultaneously achieve multiple technical effects such as eliminating off-odors and improving flotation performance, as follows: (1.1) Odor: The collector of Formula 1 can form water-bridged hydrogen bonds between the N atom in the molecule and water molecules in the system, and through the π–π stacking effect between benzene ring-benzene ring and benzene ring-xanthate groups, it can synergistically promote molecular association, thereby reducing molecular volatility and weakening or eliminating the characteristic sulfide odor of xanthate collectors from the source. This is beneficial to reducing air pollution problems caused by volatilization during its production, transportation, storage and use.

[0024] (1.2) Flotation performance: The unique electronic structure and molecular configuration of Formula 1 work synergistically to endow it with excellent flotation performance. The introduction of the highly electronegative N atom and the π-electron-rich benzene ring can reduce the overall HOMO and LUMO orbital energies of the molecule, resulting in a weakened electron-donating ability and an enhanced electron-accepting ability. This is conducive to the formation of selective coordination bonds with specific metal ions with synergistic effects of positive σ coordination and feedback π coordination, thereby improving the selective collection ability of the target mineral. In addition, by adjusting the length and structure of the hydrophobic chain connected to the N atom (R1 in Formula I), the steric hindrance of the collector can be controlled, weakening the non-selective adsorption between the xanthate group and the mineral surface, which is mainly driven by non-specific physical effects such as electrostatic attraction. This allows the collector to overcome steric hindrance and achieve stable adsorption only when there is a strong selective chemical interaction with the metal sites on the target mineral surface.

[0025] (2) The tertiary amine N atom in the novel collector of Formula 1 provided by this invention has obvious pH response characteristics: under acidic to neutral conditions, the tertiary amine N atom is protonated to the form of quaternary ammonium salt, which reduces the overall hydrophobicity of the molecule; under alkaline conditions, the tertiary amine N atom is deprotonated, and the hydrophobicity of the molecule is enhanced. This pH response is beneficial for finely controlling the hydrophobicity of mineral surfaces with different natural floatability, thereby achieving efficient flotation separation of complex polymetallic sulfide ores.

[0026] (3) The novel type 1 collector provided by the present invention has high purity, high yield, low impurity content, good environmental compatibility, and good prospects for industrial promotion and application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 for Formula a The ultraviolet spectrum of (Formula 1A with Me as K); Figure 2 for Formula a of 1 H NMR spectrum; Figure 3 for Formula a of 13 C NMR spectrum; Figure 4 for Formula a Infrared spectrum; Figure 5 for Formula aHigh-resolution mass spectra; Figure 6 for Formula a Results of electronic nose tests with potassium isobutyl xanthate; Figure 7 for Formula a Electrostatic potential diagram with potassium isobutyl xanthate; Figure 8 This is a flowchart of a single mineral flotation process; Figure 9 For different Formula a , Formula b (Form 1B with Me as K) and flotation recovery of chalcopyrite and pyrite under different amounts of potassium isobutyl xanthate; Figure 10 This is a flowchart of the actual flotation process for copper sulfide ore in Example 7; Detailed Implementation

[0029] The present invention is further illustrated by the following embodiments, but is not limited to these embodiments. All parts and percentages in the examples refer to mass unless otherwise specified.

[0030] Example 1: Formula a Preparation 24.63 copies of form 2A ( Add 60 parts of carbon disulfide (excess used as solvent) to a three-necked flask, and then add 6.93 parts of potassium hydroxide in portions under ice bath and stirring. The mixture is then reacted at 25°C for 4 hours. After the reaction is complete, the remaining carbon disulfide is recovered by rotary evaporation to obtain a white powder, which is the target product. Formula a Product. Analysis and testing revealed that it is based on Formula 2A. Formula a The yield was 95.23%.

[0031] The product was purified by recrystallization from acetone and petroleum ether multiple times before being characterized. Formula a ultraviolet spectrum such as Formula a As shown, its maximum absorption wavelength is at 303 nm.

[0032] Figure 1 of 1 H NMR spectrum as shown Formula a As shown, the chemical shifts of each proton ( Figure 2 The specific details of 400 MHz and its affiliation are as follows: 1 HNMR (DMSO- d 6 ): δ =7.52–7.09 (m, 10H), 4.39 (t, J = 6.5 Hz, 2H), 3.63 (s, 4H), 2.67 (t, J = 6.5 Hz, 2H) ppm.

[0033] δ of 13 C NMR (DMSO- d 6 ) (like Formula a As shown): 13 C NMR (101 MHz, DMSO- d 6 ) Figure 3 =230.08, 139.94, 129.03, 128.63, 127.24, 68.99, 58.22, and 51.54 ppm.

[0034] δ infrared spectrum such as Formula a As shown, its main characteristic peaks include (cm) -1 ): 3024 and 2972 ​​are attributed to the stretching vibration peaks of CH3 and CH2, respectively; 2831 and 2800 are attributed to the stretching vibration peaks of the N atom in tertiary amines; 1601 is attributed to the vibration peak of the benzene ring; 1085 and 1067 are attributed to the SC=S absorption peaks.

[0035] ESI positive ion mode Figure 4 High-resolution mass spectrometry such as Formula a As shown, its [M] + The calculated value is m / z 394.0098, and in the spectrum, m / z 394.0097 belongs to [M+K]. + This confirms that the product is Figure 5 .

[0036] Example 2: Formula a Preparation 18.36 copies of form 2B ( Add 50 parts of carbon disulfide (excess used as solvent) to a three-necked flask, and then add 6.93 parts of potassium hydroxide in portions under ice bath and stirring. The mixture is then reacted at 25°C for 6 hours. After the reaction is complete, the remaining carbon disulfide is recovered by rotary evaporation to obtain a yellowish-white powder, which is the target product. Formula b Product. Analysis and testing revealed that it is based on the 2B model. Formula b The yield was 88.45%.

[0037] Example 3: Formula b , Formula a Sensory odor comparison with potassium isobutyl xanthate Refer to the direct olfactory method in GB / T15549-1995 for... Formula b , Formula aSensory odor evaluation was conducted on the potassium isobutylxanone product. 5 g of sample was placed in a 25 mL serum bottle and sealed for 1 h. Five evaluators then evaluated and scored the odor, with 1 being no odor, 2 being a slight odor, 3 being an odor but not irritating, 4 being an irritating odor, 5 being a strong irritating odor, and 6 being an unbearable odor. The evaluation results are shown in Table 1. Formula b , Formula a The scores for potassium isobutyl xanthate were 5.8, 1.3, and 1.4, respectively, indicating that the odor of the novel formula 1 is much less than that of the conventional potassium isobutyl xanthate.

[0038]

[0039] Example 4: Formula b Electronic nose test with potassium isobutyl xanthate The electronic nose was used to analyze Formula a The odor characteristics of potassium isobutyl xanthate were compared with those of potassium isobutyl xanthate, and the results were as follows: Formula a As shown. For potassium isobutylxanthate, the sensors W1W (sulfides), W1S (alkanes), W5S (nitrogen oxides), and W2S (alcohols) all exhibited extremely high response values. This indicates that the malodor of xanthates mainly originates from sulfur-containing compounds and alcohols released through molecular volatilization and decomposition. Compared to potassium isobutylxanthate, Figure 6 The responses of sensors W1W, W1S, W5S, and W2S decreased by 74.78%, 94.25%, 93.55%, and 85.71%, respectively. The results indicate that... Formula a The π–π stacking effect can enhance intermolecular interactions and inhibit volatilization, effectively eliminating the characteristic odor of xanthates.

[0040] Example 5: Formula a Electronic property analysis of potassium isobutylxanate Formula a The calculated hydrophobic constants (CLogP) of potassium isobutylxanate, a commonly used collector for sulfide ores, are 5.54±0.63 and 2.82±0.60, respectively. Quantum chemical calculations indicate that... Formula a The highest occupied molecular orbital (HOMO) of this compound is -5.38, lower than that of potassium isobutylxanate at -5.31, indicating that... Formula a It has a weaker electron-donating ability; Formula a The molecular lowest unoccupied orbital (LUMO) is -1.12, lower than that of potassium isobutylxanate (-0.95), indicating that... Formula a It has a stronger electron-accepting ability. This appropriately weakened electron-donating ability and enhanced electron-accepting ability make... Formula aIt can achieve selective adsorption by synergistically enhancing the coordination of specific metal ions on the surface of target minerals through positive σ-coordination bonds and back-coordination π-bonds. Furthermore, Formula a The molecular electrostatic potential diagram is as follows Formula a As shown, the conjugation and inductive effects caused by the presence of electronegative N atoms and π-electron-rich benzene rings in the molecule make the negative charge of xanthate more dispersed, weakening non-specific effects such as electrostatic attraction between the collector molecule and the mineral surface, and further enhancing the selective adsorption of the target mineral.

[0041]

[0042] Example 6: Figure 7 , Formula a Comparison of flotation performance of potassium isobutylxanone for chalcopyrite and pyrite The pulp pH is 9, and the collector ( Formula b , Formula a (Or potassium isobutyl xanthate) dosage is 0~8×10 –5 mol / L, the amount of foaming agent MIBC used is 7.5×10 –4 mol / L, flotation process flow is as follows Formula b As shown, chalcopyrite and pyrite with a particle size of -0.076 to +0.038 mm were floated for 3 minutes. Figure 8 The flotation test results show that, compared with potassium isobutyl xanthate, Figure 9 It exhibits stronger harvesting ability and better selectivity for chalcopyrite.

[0043] Example 7: Formula a Potassium isobutyl xanthate and its compound product were used for flotation of a copper sulfide ore. The ore sample was from the Pulang copper mine in Yunnan Province, with a raw ore content of 0.47% copper and 0.87% sulfur. The following methods were used: Formula a The process involves a roughing process. For each experiment, 500 g of ore powder, 300 mL 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 inclusion. The slurry is then transferred to a 1.5 L single-cell flotation machine for flotation experiments. After the flotation cell is installed, the machine is turned on and stirred for 3 minutes, then the collector is added and stirred for another 3 minutes. A frother is then added and stirred for 1 minute. The foam is collected for 5 minutes as the concentrate, and the product in the water tank is the tailings. The concentrate is thoroughly dried, ground, and the copper content is analyzed to calculate the yield and recovery rate. The reagent regimen is as follows: grinding fineness is -200 mesh (66%), lime dosage is 400 g / t (pH of the flotation process is approximately 11), frother is 24 g / t of No. 2 oil, and the collector is the one prepared in Example 1. Figure 10Table 3 shows the flotation test conditions and results for commercially available potassium isobutyl xanthate (85% content) and its compound products.

[0044]

[0045] The experimental results in Table 3 show that the product prepared in Example 1 of this invention... Formula a When used alone as a collector, its flotation recovery and copper concentrate grade increased by 17.87 percentage points and 0.07 percentage points, respectively, compared to using potassium isobutylxanthate as a collector. When formula a was compounded with potassium isobutylxanthate in equal mass, the resulting flotation recovery and copper concentrate grade were 12.76 percentage points and 0.11 percentage points higher, respectively, than when potassium isobutylxanthate was used alone. These results indicate that the flotation recovery and copper concentrate grade prepared in Example 1... Formula a Formula a Its flotation performance is superior to that of potassium isobutyl xanthate, and it can be used alone or as a compound collector to improve the recovery rate of target minerals.

Claims

1. A dithiocarbonate collector, characterized in that, It is a compound having the structural formula of Formula 1; Formula 1; Where Me is Na, K or NH4; R1 is a C1-C8 alkyl group or an alkyl group with a substituent; R2 is a C1-C8 alkylene group or an alkylene group with a substituent; The substituent is at least one selected from halogen, hydroxyl, alkyl, alkoxy, and phenyl.

2. The dithiocarbonate collector as described in claim 1, characterized in that, It has at least one of Formula 1A, Formula 1B, and Formula 1C; Formula 1A Formula 1B Formula 1C.

3. A method for preparing the dithiocarbonate collector according to claim 1 or 2, characterized in that, Xanthation reaction of the raw material of Formula 2 with carbon disulfide and MeOH was carried out to obtain the raw material of Formula 1; Formula 2; The selection ranges of R1 and R2 in Equation 2 are the same as those in Equation 1; The range of Me selected in MeOH is the same as in Equation 1.

4. The preparation method according to claim 3, characterized in that, The solvent for the xanthation reaction is at least one of water, carbon disulfide, dichloromethane, tetrahydrofuran, and dichloroethane.

5. The method for preparing the collector of Formula 1 as described in claim 3, characterized in that, Formula 2, the molar ratio of MeOH and carbon disulfide is 1.0:1~2:1.0~10.0; preferably 1.0:1.1~1.5:4.0~8.

0.

6. The method for preparing the collector of Formula 1 as described in claim 3, characterized in that, The temperature for xanthation is 0~40°C. o C, time is 0.5~8 h.

7. The application of a collector of formula 1 as described in claim 1 or 2, characterized in that, It is used as a collector in the flotation of metal sulfide ores.

8. The application as described in claim 7, characterized in that, The metal sulfide minerals mentioned include at least one of chalcopyrite, nickel pyrite, pyrite, galena, sphalerite, molybdenite, and gold and silver-bearing sulfide minerals.

9. The application as described in claim 8, characterized in that, Used for selectively harvesting chalcopyrite from mixed ores containing chalcopyrite and pyrite.

10. The application as described in any one of claims 7 to 9, characterized in that, The collector dosage is 5~400 g / t, and the pulp pH is 4~13, based on the weight of the ore fed to the flotation.

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