A composite collector for floating silicate minerals and a weak alkaline flotation method for separating quartz and feldspar
By combining triazine hexameric quaternary ammonium salt compounds with fatty acid anionic collectors, highly efficient and selective separation of quartz and feldspar is achieved under weakly alkaline conditions. This solves the problems of insufficient selectivity and equipment corrosion in existing technologies, and yields high-grade mineral products with high recovery rates.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CENT SOUTH UNIV
- Filing Date
- 2026-06-09
- Publication Date
- 2026-07-21
AI Technical Summary
Existing technologies struggle to achieve efficient and environmentally friendly selective separation of quartz and feldspar in mild environments. Conventional collectors lack selectivity and pose a risk of equipment corrosion.
A composite collector system combining triazine hexameric quaternary ammonium salts and fatty acid anionic collectors works synergistically under weakly alkaline conditions. It utilizes the differences in active sites on mineral surfaces to achieve selective adsorption, forming a hydrophobic coating layer and improving the collecting capacity and selectivity.
It achieves efficient separation of quartz and feldspar, improves recovery rate and grade, reduces equipment corrosion risk and environmental pollution, has wide adaptability and high operational stability.
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Figure CN122424928A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a composite collector for flotation of silicate minerals and a weakly alkaline flotation method for separating quartz and feldspar, belonging to the field of mineral flotation. Background Technology
[0002] Quartz and feldspar, as widely coexisting and highly valuable basic non-metallic mineral raw materials in nature, are indispensable in glass, ceramics, electronics, and many other high-tech fields. With the increasing depletion of single high-quality mineral resources, the demand for high-purity quartz and feldspar products is becoming increasingly urgent. However, the efficient separation of these two minerals has always been a major challenge in the mineral processing field. Because quartz and feldspar both belong to framework silicate minerals, their crystal structures and physicochemical properties are extremely similar, especially their zero-electric points, which highly overlap. This results in their surface electrical properties changing in aqueous solutions with essentially the same pattern, making it extremely difficult to achieve effective separation using conventional gravity separation, magnetic separation, or simple flotation processes.
[0003] Currently, the industrial process mainly relies on froth flotation to separate quartz and feldspar, but the existing process system has significant limitations. Neutral or alkaline flotation processes, which have received considerable attention in recent years, are generally limited by the insufficient collecting capacity and selectivity of existing conventional collectors, making it difficult to achieve ideal separation grades and recovery rates.
[0004] For example, Chinese patent application CN113441283A discloses a method for positive flotation of quartz from a mixed quartz and feldspar ore under neutral pH conditions. This method involves adding short-chain diamines as feldspar inhibitors and long-chain amines as collectors, achieving quartz flotation under fluorine-free and acid-free neutral conditions. However, this method requires strict control of the concentrations of the two carbon chain amines, and suffers from drawbacks such as a long flotation process and low quartz recovery rate.
[0005] To overcome the aforementioned technical bottlenecks, it is urgent to develop a new type of collector system that is efficient, environmentally friendly, and widely adaptable, so as to achieve green and efficient separation of the two under mild environmental conditions. Summary of the Invention
[0006] To address the problems in existing technologies where the flotation separation of quartz and feldspar is difficult to balance environmental friendliness, high efficiency, and high selectivity, the first objective of this invention is to provide a composite collector for flotation of silicate minerals. Through the synergistic effect of triazine hexameric quaternary ammonium salt compounds and fatty acid anionic collectors, it is possible to achieve good foaming properties and strong selectivity for silicate minerals.
[0007] The second objective of this invention is to provide a weakly alkaline flotation method for separating quartz and feldspar. This method can achieve efficient separation of quartz and feldspar in a weakly alkaline environment, avoid severe corrosion of flotation equipment and pipelines by strong acid systems, and extend the service life of the equipment.
[0008] To achieve the above-mentioned technical objectives, the present invention provides a composite collector for flotation of silicate minerals, comprising a triazine hexameric quaternary ammonium salt compound and a fatty acid anionic collector; the triazine hexameric quaternary ammonium salt compound has the structural formula of Formula 1:
[0009]
[0010] Formula 1;
[0011] Where R is a quaternary ammonium salt group.
[0012] The composite collector in this invention achieves excellent foaming performance and strong selectivity for silicate minerals under weakly alkaline conditions through the synergistic effect of triazine hexameric quaternary ammonium salt compounds and fatty acid anionic collectors. The hydroxyl and quaternary ammonium groups on multiple branches in the molecular structure of the triazine hexameric quaternary ammonium salt compound give the compound good water solubility and dispersibility in the pulp. Simultaneously, the conjugated groups composed of triazine rings and amines in the middle of the molecule coordinate with the active sites on the surface of silicate minerals. This multi-point anchoring effect increases the adhesion and intensity on the target mineral surface, improving the catchability of the target mineral. Furthermore, the rigid triazine isolation structure in the molecular structure can be orderly arranged at the gas-liquid interface, significantly improving the liquid film fluidity of the bubbles, reducing foam stability, and enhancing foaming performance during flotation. Meanwhile, the combined use of fatty acid anionic collectors and triazine hexameric quaternary ammonium salts can synergistically adsorb onto the surface of silicate minerals, which can significantly improve the collection capacity of target minerals; however, they can also compete for adsorption on the mineral surface, causing the reagents on the surface of minerals that should be floated to be desorbed, thus reducing floatability.
[0013] Experiments revealed that while triazine hexaquammonium salt compounds exhibit strong collecting ability for silicate minerals when used alone, their selectivity for quartz and feldspar is not significantly different, especially under weakly alkaline conditions, where both are easily floated, making effective separation difficult. However, the addition of a fatty acid anionic collector demonstrates strong chemisorption of aluminum active sites on the feldspar surface, preferentially occupying these sites and effectively inhibiting the adsorption of triazine hexaquammonium salt compounds. Simultaneously, on the quartz surface, due to the lack of aluminum sites, the fatty acid anionic collector adsorbs weakly, allowing the triazine hexaquammonium salt compounds to adsorb normally and form a hydrophobic layer. Furthermore, the two can co-adsorb through hydrophobic interactions, forming a dense hydrophobic coating layer. Moreover, the composite collector achieves both high collecting power and high selectivity at a lower total dosage, with further improved foaming properties and easier defoaming, which helps reduce fine mud entrainment and subsequent dewatering operations.
[0014] As a preferred embodiment, R has the structural formula of Equation 2:
[0015]
[0016] Formula 2;
[0017] in, The bonding sites are represented by X, which represents the equilibrium anion. R1 is an alkylene group, and R2 to R4 are the same or different alkyl or aryl groups.
[0018] As a preferred embodiment, X is a halogen, such as F, Cl, Br, etc.
[0019] As a preferred embodiment, the fatty acid anionic collector includes at least one of oleic acid and its salts, and oxidized paraffin soap.
[0020] As a preferred embodiment, R1 is methylene, R2 and R4 are selected from the same C1-C3 straight-chain alkyl group, and R3 is selected from C1-C4. 18 Straight-chain alkyl groups or C6-C7 aromatic alkyl groups; such as benzyl, n-hexyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl or n-octadecyl.
[0021] Further preferably, R3 is n-octyl or n-decyl.
[0022] As a preferred embodiment, the fatty acid anion collector is oleic acid and its salts, such as sodium and potassium salts. When further preferred functional groups and fatty acid anion collectors are used, compounds with even better overall performance can be obtained.
[0023] As a preferred embodiment, the mass ratio of the triazine hexameric quaternary ammonium salt compound to the fatty acid anionic collector is (1~4):(4~1). Within the preferred mass ratio range of this invention, the selective separation of quartz and feldspar can be effectively achieved.
[0024] Further preferably, the mass ratio of the triazine hexameric quaternary ammonium salt compound to the fatty acid anionic collector is 1:4 or 3:2. When using a further preferred range, the grade of feldspar in the tailings can be significantly improved.
[0025] Taking X as chlorine and R1 as methylene as an example, as a preferred embodiment, the preparation process of the triazine hexameric quaternary ammonium salt compound is as follows: melamine and triethylamine are dissolved in N,N-dimethylformamide, epichlorohydrin is added, and a ring-opening alkylation reaction is carried out to obtain the intermediate of formula 3; then the intermediate of formula 3 is subjected to a quaternization reaction with a compound having structural formula 4 to obtain the product.
[0026]
[0027] Formula 3;
[0028]
[0029] Equation 4;
[0030] Wherein, R2 and R4 are selected from the same C1~C3 straight-chain alkyl group, and R3 is selected from C1~C3. 18 Straight-chain alkyl groups or C6-C7 aromatic alkyl groups, such as benzyl, n-hexyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, or n-octadecyl.
[0031] As a preferred embodiment, the ring-opening alkylation reaction is carried out at a temperature of 100-110°C for a time of 40-48 hours.
[0032] As a preferred embodiment, the quaternization reaction is carried out at a temperature of 75-85°C for 16-20 hours.
[0033] As a preferred embodiment, the silicate minerals include at least one selected from quartz, potassium feldspar, sodium feldspar, and spodumene. This invention enables the efficient harvesting of a variety of silicate minerals.
[0034] This invention also provides a weakly alkaline flotation method for separating quartz and feldspar, the method comprising the following steps:
[0035] S1 involves grinding and slurry preparation of raw mineral ore containing both quartz and feldspar to obtain a slurry.
[0036] S2 adds flotation reagents, including the composite collector described in any one of claims 1 to 5, to the slurry for flotation to obtain a quartz-containing concentrate and a feldspar-containing tailings.
[0037] Although quartz and feldspar both belong to framework silicates, there are fundamental differences in the type and density of their surface active sites. Part of the Si in feldspar crystals... 4+ By Al 3+The substitution of metals in feldspar results in a negatively charged framework. To maintain electroneutrality, the feldspar surface contains a large number of alkali metal ions and exposed aluminum atoms (Al–O, Al–OH sites). In contrast, the quartz framework is composed of pure Si–O–Si, with a surface primarily composed of silanol groups (Si–OH) and extremely low aluminum content. The composite collector of this invention utilizes this difference. Triazine hexameric quaternary ammonium salts alone exhibit strong electrostatic adsorption on both quartz and feldspar under weakly alkaline conditions (both surfaces are negatively charged), thus lacking selectivity. After adding a fatty acid anionic collector, its carboxylate group is completely deprotonated under weakly alkaline conditions (pKa approximately 4.7~5.0), becoming negatively charged, but still capable of strong chemisorption on the aluminum sites on the feldspar surface. This chemisorption is not hindered by electrostatic repulsion. Simultaneously, the weakly alkaline conditions partially deprotonate the silanol groups on the quartz surface, enhancing the electrostatic attraction and hydrogen bonding between the triazine hexameric quaternary ammonium salt and the quartz surface, while the adsorption of the fatty acid anionic collector on the quartz surface remains weak. Therefore, under weakly alkaline conditions, the adsorption difference between the two is maximized: the fatty acid anionic collector has a strong enough chemisorption of feldspar to competitively inhibit triazine hexaquammonium salt compounds; while the weak adsorption of quartz is insufficient to interfere with the anchoring of triazine hexaquammonium salt compounds, thus achieving selective separation.
[0038] As a preferred embodiment, the grinding process is performed such that the mass of the mineral with a fineness of -200 mesh is 60-90 wt%.
[0039] As a preferred embodiment, the slurry concentration is 25-45 wt%, and the pH is 8.0-10.0. A pH adjuster can be added during the process. This invention enables the selective separation of quartz and feldspar in a weakly alkaline environment. A further preferred pH is 8.5-9.5, and within a further preferred pH range, the adsorption difference between quartz and feldspar can be maximized.
[0040] As a preferred embodiment, the grinding process can be followed by desliming treatment based on the mineral properties and actual operation. Preferably, the desliming treatment involves standing for 2-3 times, with each session lasting 3-5 minutes.
[0041] As a preferred embodiment, the flotation includes at least one roughing stage, wherein the total amount of the composite collector used in the roughing process is 10-1000 g / t relative to the raw ore. More preferably, the total amount of the composite collector used is 200-400 g / t relative to the raw ore. Even more preferably, the total amount of the composite collector used is 300 g / t relative to the raw ore.
[0042] In order to further improve the flotation effect, inhibitors, frothers, etc. can be added to the flotation reagents according to different minerals and requirements.
[0043] Compared with the prior art, the present invention has the following beneficial effects:
[0044] (1) This invention combines triazine hexameric quaternary ammonium salt compounds with fatty acid anionic collectors, overcoming the limitation of poor selectivity of single collectors. The six hydroxyl groups and quaternary ammonium salt groups on the side chains of triazine hexameric quaternary ammonium salt compounds can form multiple strong adsorption sites on the surface of silicate minerals. Combined with fatty acid anionic collectors, the two generate a strong co-adsorption synergistic effect at the mineral-water interface through electrostatic attraction and hydrophobic association. This synergistic effect directionally amplifies the hydrophobicity difference between the surfaces of quartz and feldspar, thereby achieving efficient separation of quartz and feldspar and obtaining high-grade and high-recovery target mineral products.
[0045] (2) The collector system of the present invention overcomes the serious environmental pollution problems of traditional fluoride and acid methods. This synergistic reagent system does not require the addition of highly toxic and corrosive hydrofluoric acid as an activator, and can maintain excellent collection performance in a milder pH environment (weakly alkaline conditions). This not only fundamentally eliminates the harm of fluoride ions to the environment and greatly reduces the difficulty and cost of treating mineral processing wastewater, but also avoids the serious corrosion of flotation equipment and pipelines by strong acid systems, significantly extending the service life of the equipment.
[0046] (3) The composite collector system used in this invention can still maintain good dispersibility and excellent harvesting ability in water bodies at room temperature or even low temperature, which greatly reduces the construction difficulty in the process.
[0047] (4) The process of the present invention has a wide tolerance and high operational stability, and can be widely adapted to the development and utilization of quartz-feldspar symbiotic mineral resources of different grades and properties. Attached Figure Description
[0048] Figure 1 The molecular structure of THQ-8 prepared in Example 1 is shown.
[0049] Figure 2 The infrared spectrum of THQ-8 prepared in Example 1.
[0050] Figure 3 The molecular structure of THQ-10 prepared in Example 2.
[0051] Figure 4 The infrared spectrum of THQ-10 prepared in Example 2.
[0052] Figure 5 This is a flow chart of the flotation process in Example 3. Detailed Implementation
[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below, but are not limited to the embodiments.
[0054] Example 1
[0055] Preparation of THQ-8
[0056] Under nitrogen protection, triethylamine (2.8 mL, 0.0201 mol) and melamine (5.000 g, 0.0397 mol) were dissolved in N,N-dimethylformamide (31.000 g, 0.4241 mol) in a three-necked flask equipped with a stirrer at room temperature. Epichlorohydrin (31.500 g, 0.3405 mol) was then slowly added dropwise to the flask at a rate of 5 drops / min. After the addition was complete, the mixture was heated to 105°C and refluxed at this temperature for 48 hours. After the reaction was complete, the solution was concentrated under reduced pressure using a rotary evaporator. The resulting residual solid was washed once with n-hexane and then recrystallized twice with acetone. After vacuum drying, a brown solid intermediate was obtained.
[0057] The intermediate prepared above (3.000 g, 0.0015 mol) was added to a three-necked flask, followed by distilled water (45 mL), N,N-dimethylformamide (45 mL), and sodium hydroxide aqueous solution (0.500 mol / L, 10 mL) to dissolve it. Under nitrogen protection and vigorous stirring, N,N-dimethyloctylamine (1.65 g, 0.0105 mol), pre-dissolved in ethanol (30 mL), was slowly added to the reaction mixture. The reaction system was then heated to 85°C and refluxed for 16 hours. After the reaction was complete, the solvent was removed by vacuum distillation. The resulting residual solid was washed once with n-hexane and then recrystallized twice with acetone. The product was dried under vacuum at 65°C to obtain THQ-8. The molecular structure and infrared spectrum are shown below. Figure 1 , Figure 2 As shown.
[0058] Table 1 Infrared Spectral Analysis of THQ-8
[0059]
[0060] Example 2
[0061] Preparation of THQ-10
[0062] Under nitrogen protection, triethylamine (2.8 mL, 0.0201 mol) and melamine (5.000 g, 0.0397 mol) were dissolved in N,N-dimethylformamide (31.000 g, 0.4241 mol) in a three-necked flask equipped with a stirrer at room temperature. Epichlorohydrin (31.500 g, 0.3405 mol) was then slowly added dropwise to the flask at a rate of 5 drops / min. After the addition was complete, the mixture was heated to 105°C and refluxed at this temperature for 48 hours. After the reaction was complete, the solution was concentrated under reduced pressure using a rotary evaporator. The resulting residual solid was washed once with n-hexane and then recrystallized twice with acetone. After vacuum drying, a brown solid intermediate was obtained.
[0063] The intermediate prepared above (3.000 g, 0.0015 mol) was added to a three-necked flask, followed by distilled water (45 mL), N,N-dimethylformamide (45 mL), and sodium hydroxide aqueous solution (0.500 mol / L, 10 mL) to dissolve it. Under nitrogen protection and vigorous stirring, N,N-dimethyldecylamine (1.95 g, 0.0105 mol), pre-dissolved in ethanol (30 mL), was slowly added to the reaction mixture. The reaction system was then heated to 85°C and refluxed for 16 hours. After the reaction was complete, the solvent was removed by vacuum distillation. The resulting residual solid was washed once with n-hexane and then recrystallized twice with acetone. The product was dried under vacuum at 65°C to obtain THQ-10. The molecular structure and infrared spectrum are shown below. Figure 3 , Figure 4 As shown.
[0064] Table 2 Infrared Spectral Analysis of THQ-10
[0065]
[0066] Example 3
[0067] Flotation experiment of triazine hexameric quaternary ammonium salt compound with sodium oleate as a collector on mica tailings in Fujian Province
[0068] A mica tailings sample from Fujian Province contained 9.17 wt% Al2O3 and 75 wt% of the ore was ground to a fineness of -200 mesh. When using the triazine hexameric quaternary ammonium salt compound prepared in Examples 1 and 2 and sodium oleate composite collector, the roughing pH was adjusted to 9.0. After one roughing flotation process, the flotation results are shown in Table 3.
[0069] Table 3. Flotation experiment of mica tailings in Fujian Province
[0070]
[0071] Flotation results showed that when the THQ-8 / NaOL mass ratio was 3:2, the feldspar grade in the tailings was significantly improved. Furthermore, reagent ratios of 2:1, 3:2, and 4:1 all effectively and selectively separated quartz and feldspar. When the THQ-10 / NaOL mass ratio was 1:4, the Al2O3 grade in the tailings reached 17.75%, indicating that this composite reagent system could produce qualified feldspar products.
Claims
1. A composite collector for flotation of silicate minerals, characterized in that: It includes triazine hexameric quaternary ammonium salt compounds and fatty acid anion collectors; the triazine hexameric quaternary ammonium salt compounds have the structural formula of Formula 1: ； Formula 1; Where R is a quaternary ammonium salt group.
2. The composite collector for flotation of silicate minerals according to claim 1, characterized in that: The R has the structural formula of Equation 2: ； Formula 2; in, The bonding site is X, which represents the equilibrium anion. R1 is an alkylene group, and R2 to R4 are the same or different alkyl or aryl groups. The fatty acid anionic collector includes at least one of oleic acid and its salts, and oxidized paraffin soap.
3. The composite collector for flotation of silicate minerals according to claim 2, characterized in that: R1 is methylene, R2 and R4 are selected from the same C1-C3 straight-chain alkyl group, and R3 is selected from C1-C3 alkyl group. 18 Straight-chain alkyl groups or C6-C7 aromatic alkyl groups; The fatty acid anionic collector is oleic acid and its salt.
4. A composite collector for flotation of silicate minerals according to any one of claims 1 to 3, characterized in that: The mass ratio of the triazine hexameric quaternary ammonium salt compound to the fatty acid anionic collector is (1~4):(4~1).
5. The composite collector for flotation of silicate minerals according to claim 4, characterized in that: The silicate minerals include at least one of quartz, potassium feldspar, sodium feldspar, and spodumene.
6. A weakly alkaline flotation method for separating quartz and feldspar, characterized in that: step include: S1 involves grinding and slurry preparation of raw mineral ore containing both quartz and feldspar to obtain a slurry. S2 adds flotation reagents, including the composite collector described in any one of claims 1 to 5, to the slurry for flotation to obtain a quartz-containing concentrate and a feldspar-containing tailings.
7. The weakly alkaline flotation method for separating quartz and feldspar according to claim 6, characterized in that: The grinding process is performed to ensure that the mass of minerals with a fineness of -200 mesh accounts for 60~90 wt%.
8. The weakly alkaline flotation method for separating quartz and feldspar according to claim 6, characterized in that: The slurry has a concentration of 25-45 wt% and a pH of 8.0-10.
0.
9. A weakly alkaline flotation method for separating quartz and feldspar according to claim 7 or 8, characterized in that: The flotation includes at least one roughing process, wherein the total amount of composite collector used in the roughing process is 10~1000g / t relative to the raw ore.