High-efficiency collector for flotation separation of quartz and potassium feldspar, and preparation method and application thereof

Abstract

The application discloses a high-efficiency collector for flotation separation of quartz and potassium feldspar and a preparation method and application thereof, and belongs to the flotation reagent field. The quartz collector has the following structure, wherein R1 is selected from C8-C20 alkyl, and R2 is selected from H or methyl. The collector is applied to flotation separation of quartz and potassium feldspar minerals, and the content of quartz in the minerals is 30-90 wt%. The collector can exhibit good selectivity to medium content and high content quartz under an alkaline flotation environment, has a wide application range, and also exhibits excellent recovery rate in the high quartz content range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of flotation reagents, and relates to a high-efficiency collector for flotation separation of quartz and potassium feldspar, and a preparation method and application thereof. BACKGROUND

[0002] At present, the flotation separation of silicate minerals quartz and feldspar mainly relies on traditional anionic collectors or cationic collectors. In particular, the industry has always relied on anionic or cationic single collectors for flotation separation. However, the single anionic collector needs to be activated in a sulfuric acid medium at pH 2-3 to float feldspar; the single cationic collector floats quartz in a sodium carbonate medium at pH 9-11. These single-charge collectors have poor selectivity, harsh flotation conditions, and other problems. In the prior art, a combination of collectors is also used, but the acid method combination such as fatty acid + sodium petroleum sulfonate has high acid consumption, heavy equipment corrosion, and large environmental burden, and the alkali method anionic / cationic reagent has the common defects of complex preparation, strict water quality requirements, and insufficient selectivity, resulting in low separation efficiency and high cost of complex ores, which has become a bottleneck restricting the large-scale production of high-purity quartz.

[0003] In recent years, around the goal of high efficiency, low cost, and environmental friendliness, the research on flotation reagents has made significant progress. For example, Chinese Patent Application CN113441283A discloses a method for positively floating quartz from a mixture of quartz and feldspar under neutral pH conditions, which adds a short carbon chain diamine as a feldspar depressant and a long carbon chain amine as a collector to realize the flotation of quartz under neutral conditions without fluorine and acid. However, this method needs to strictly control the concentration of the two carbon chain amines, has a long flotation process, and has low recovery rate of quartz.

[0004] For example, Chinese Patent Application CN114082534A discloses an oxidized mineral amphoteric collector, a preparation method and application thereof, which reacts amine with dichloroacetic acid, and then reacts with alkali to obtain a collector that can replace fatty acid collectors as an iron ore, fluorite ore, and phosphate ore collector. However, this collector cannot produce high selectivity to quartz for the two minerals quartz and potassium feldspar with small differences in surface properties. SUMMARY

[0005] To overcome the problems in the prior art, the first object of the present application is to provide a quartz collector for flotation separation of quartz and potassium feldspar, which can exhibit good selectivity to medium and high content quartz in an alkaline flotation environment, has a wide application range, and also exhibits excellent recovery rate in a high quartz content range.

[0006] The second object of the present application is to provide a preparation method of the quartz collector, which can be prepared by only one step reaction, and has the advantages of simple steps and easy availability of raw materials.

[0007] A third object of the present application is to provide an application of a quartz collector, which can achieve efficient and selective collection of quartz minerals through a short process flotation step under fluoride-free and acid-free conditions.

[0008] In order to achieve the above technical purposes, the present application provides a quartz collector for flotation separation of quartz and potassium feldspar minerals, the quartz collector has the following structural formula:

[0009] ;

[0010] Formula 1;

[0011] In the formula, R1 is selected from C8-C20 alkyl, and R2 is selected from H or methyl.

[0012] As a preferred scheme, the content of quartz in the mineral is 30-90wt%.

[0013] The collector of the present application can exhibit good selectivity to medium and high content of quartz in an alkaline flotation environment, and also exhibit excellent recovery rate in a high quartz content range. The key lies in the synergistic effect of the molecular structure and groups of the collector. Quartz and potassium feldspar belong to silicate minerals, have similar chemical bond properties, close physicochemical characteristics, similar charging mechanisms in aqueous solution, and similar isoelectric points, which makes it difficult for traditional collectors to effectively distinguish between the two, especially in mixed ores with a high proportion of quartz, potassium feldspar is easily entrained with foam, which seriously affects the grade of quartz. In the collector of the present application, the long-chain alkyl group as a strong hydrophobic group significantly enhances the hydrophobicity of the mineral surface, improves the bubble adhesion and flotation efficiency; the -NH- group in the middle is easy to form positively charged amine ions under alkaline conditions, while the quartz mineral surface is negatively charged under alkaline conditions, and these positively charged ions can be electrostatically adsorbed with the negatively charged sites on the mineral surface, and the specific adsorption on the quartz surface is strengthened, and due to the synergistic effect with the cyclohexyl group, good selectivity is achieved in medium and high content of quartz; the special spatial structure of the ester group can produce different steric hindrance effects with the two silicate minerals of quartz and potassium feldspar; in addition, the cyclohexyl group not only increases the additional hydrophobicity, but also optimizes the spatial arrangement of the collector on the quartz surface, making the adsorption more compact and efficient, thereby further improving the recovery rate in the high quartz content range. In contrast, the collector has a weaker effect on potassium feldspar under alkaline conditions.

[0014] As a preferred scheme, R1 is C8-C12 alkyl, and R2 is methyl. It is found that when further preferred groups are used, more excellent selectivity and recovery rate effects can be exhibited.

[0015] As a preferred embodiment, the quartz content in the mineral is 70-90 wt%. Within a further preferred range of quartz content, the collector of the present invention exhibits both selectivity for quartz and excellent recovery rate.

[0016] The present invention also provides a method for preparing a quartz collector, which involves dissolving R1-NH2 in an alkanolic solvent, and then adding a cyclohexyl ester compound of formula 2 to carry out an addition reaction to obtain the quartz collector.

[0017] ;

[0018] Formula 2;

[0019] Wherein, R1 is selected from alkyl groups of C8 to C20, and R2 is selected from H or methyl.

[0020] The preparation method of the present invention is simple, and a product with a high yield can be obtained through only one addition reaction, avoiding the risk of introducing impurities and reducing the purity of the product through multiple reactions.

[0021] This invention allows for the preparation of the quartz collector using existing methods.

[0022] As a preferred embodiment, the cyclohexyl ester compound is cyclohexyl methacrylate; and R1-NH2 is dodecylamine.

[0023] As a preferred embodiment, the molar ratio of R1-NH2 to the cyclohexyl ester compound of Formula 2 is 1:(1.1 to 5). Within the preferred molar ratio range of this invention, it is advantageous to obtain a collector with optimal performance. A more preferred molar ratio is 1:(1.2 to 1.3).

[0024] As a preferred embodiment, the alkanol solvent is selected from at least one of methanol, ethanol, propanol, and ethylene glycol. Further, the alkanol solvent is selected from at least one of methanol and ethanol.

[0025] As a preferred embodiment, the amount of the alkanoic solvent used is 4 to 8 times the mass of R1-NH2. This is the amount of alkanoic solvent used in this invention.

[0026] In this invention, the higher the purity of the alkanoic solvent, the better it is to obtain a collector with higher purity.

[0027] As a preferred embodiment, the addition reaction conditions are: a temperature of 65-70°C and a time of 6-15 hours. The addition reaction temperature used in this invention is slightly higher, which is beneficial for the dissolution of cyclohexyl ester compounds, thereby facilitating the full introduction of long-chain amino groups, and also helps to avoid the formation of side reactions.

[0028] Finally, the present invention also provides an application of a quartz collector for flotation separation of quartz and potassium feldspar minerals, wherein the quartz content in the minerals is 30-90 wt%.

[0029] As a preferred embodiment, the application process is as follows: a raw ore containing both quartz and potassium feldspar minerals is prepared to an alkaline pH to obtain a slurry; flotation reagents, including the quartz collector of Formula 1, are added to the slurry for flotation to obtain quartz froth concentrate and potassium feldspar tailings. The collector of this invention can achieve selective collection of quartz minerals with medium and high content in a fluorine-free and acid-free alkaline environment, has a wide range of applications, and exhibits excellent recovery rates even in the high quartz content range.

[0030] As a preferred embodiment, the pH is 7-12. Within the pH range of this invention, as the pH increases, the flotation rate of pure quartz minerals or pure potassium feldspar minerals shows a trend of first increasing and then decreasing. However, there is a significant difference in the flotation rates of the two minerals, and their pH inflection points are different. Therefore, within this pH range, selective separation can be achieved by selecting an appropriate amount of collector.

[0031] As a preferred embodiment, the amount of the quartz collector relative to the amount of the raw ore is 5–200 mg / L; the quartz content in the mineral is 70–90 wt%. Due to the coexistence of cyclohexyl groups and ester groups in the collector of this invention, the collecting performance of the collector is significantly improved, thus achieving good results with low collector dosage and reducing reagent costs. Further preferably, an agent dosage of 15–25 mg / L will produce the best selective collecting effect. Of course, this limitation does not apply if the pH range is optimal.

[0032] As a preferred embodiment, the flotation process further includes at least one cleaning stage. Experiments have shown that adding at least one cleaning stage on top of the roughing stage can further increase the SiO2 grade in the concentrate, decrease the K2O grade, and further improve selectivity. The collector of this invention can be used for the purification of various quartz products.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The quartz collector provided by the present invention contains long-chain alkyl hydrophobic groups, -NH- groups, ester groups and cyclohexyl groups. This special functional group and its connection mode enable the collector of the present invention to show good selectivity for medium and high quartz content under alkaline flotation environment, and also show excellent recovery rate in the high quartz content range.

[0035] (2) The quartz collector of the present invention is applicable to a wide range of quartz contents, has strong collection specificity, and has good collection effect. Compared with existing collectors, it has a significant advantage in dosage.

[0036] (3) The method for preparing the quartz collector of the present invention can be obtained by a single reaction step, which has the advantages of simple steps and readily available raw materials.

[0037] (4) The quartz collector of the present invention not only has obvious selectivity for potassium feldspar mixed minerals with quartz content of 70~90wt%, but also has a recovery rate of more than 80% after only one roughing process. It can carry out precise flotation process of quartz minerals according to content, which greatly reduces the cost of collector and improves flotation efficiency. Attached Figure Description

[0038] Figure 1 The chemical formula of the quartz collector prepared in the embodiments of the present invention is shown.

[0039] Figure 2 This is a flotation process flow diagram of the quartz collector in Example 1 of the present invention.

[0040] Figure 3 A flow chart of a refined flotation process is provided for the quartz collector in Example 3 of the present invention.

[0041] Figure 4 The hydrogen nuclear magnetic resonance spectrum of N-dodecyl-β-amino-1-methylpropionic acid cyclohexyl ester prepared in the embodiments of the present invention.

[0042] Figure 5 The carbon NMR spectrum of N-dodecyl-β-amino-1-methylpropionic acid cyclohexyl ester prepared in the embodiments of the present invention. Detailed Implementation

[0043] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0044] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0045] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0046] In the following examples and comparative examples, the quartz collector was obtained by the following method:

[0047] N-Dodecyl-β-amino-1-methylpropionate cyclohexyl ester was synthesized from dodecylamine and cyclohexyl methacrylate. 100 mL of ethanol and 0.1 mol of dodecylamine were added to a 500 mL three-necked flask equipped with a serpentine condenser. The mixture was heated to 30 °C with stirring under reflux for 30 min until the dodecylamine was completely dissolved. Then, 0.12 mol of cyclohexyl methacrylate was slowly added dropwise, and the mixture was heated to 70 °C with stirring under reflux for 6 hours. After the reaction was complete, methanol (which can be recovered and reused) and low-boiling substances were removed from the reaction product using a rotary evaporator to obtain the final product. The resulting quartz collector has the following structural formula (Equation 3):

[0048] ;

[0049] Formula 3.

[0050] The accuracy of its structure was verified by nuclear magnetic resonance, and the experimental results are as follows: Figure 4 and Figure 5 As shown, its 1 The δ values ​​and their assignments for each H ion in the H₂-NMR spectrum are as follows: 1 H NMR (400 MHz, DMSO) δ 4.74 (dt, J = 8.4, 4.3Hz, 1H), 2.68 (td, J = 9.5, 2.8 Hz, 1H), 2.57 – 2.51 (m, 1H), 2.44 (q, J =2.8 Hz, 1H), 1.78 – 1.74 (m, 2H), 1.51 – 1.34 (m, 10H), 1.31 – 1.27 (m, 2H), 1.23 (s, 18H), 1.03 (d, J = 6.7 Hz, 3H), 0.88 – 0.82 (m, 3H). That 13 The δ values ​​and their assignments for each C ion in the C-NMR spectrum are as follows: 13 C NMR (101 MHz, DMSO) δ 174.47, 71.85, 52.56,49.06, 48.50, 31.19, 30.85, 29.45, 28.94, 28.59, 26.65, 24.82, 22.89, 21.98,14.90,13.80.

[0051] Example 1

[0052] A comparison of the flotation performance of quartz collector N-dodecyl-β-amino-1-methylpropionate cyclohexyl ester and dodecylamine in the flotation of pure quartz minerals includes the following steps:

[0053] Single-mineral flotation experiments were conducted on an XFG type flotation machine at Jilin Exploration Machinery Plant, with an impeller speed of 1992 rpm. For each mineral, 2g of quartz mineral sample (particle size -0.074mm to +0.038mm) was added to the flotation cell and mixed with 40 mL of deionized water. NaOH was added sequentially as a pH adjuster and flotation collector, with a 2-minute interval between each operation. Following this, foaming was performed for 1 minute, followed by skimming for 2 minutes. The resulting upper foam product and the product in the cell were dried and weighed in petri dishes, and the flotation recovery rate was calculated. Each experiment was repeated three times. The pH, type of collector, and dosage were adjusted according to the experimental requirements. The results are shown in Tables 1 and 2.

[0054] Table 1. Results of flotation performance tests (%) of dodecylamine and N-dodecyl-β-amino-1-methylpropionate cyclohexyl ester on pure quartz minerals.

[0055]

[0056] Table 2. Results of experimental study on the effect of dodecylamine and N-dodecyl-β-amino-1-methylpropionate dosage on the flotation performance of pure quartz minerals (%)

[0057]

[0058] Example 2

[0059] A comparison of the flotation performance of N-dodecyl-β-amino-1-methylpropionate cyclohexyl ester and dodecylamine in the flotation of pure potassium feldspar minerals includes the following steps:

[0060] Single-mineral flotation experiments were conducted on an XFG type flotation machine at Jilin Exploration Machinery Plant, with an impeller speed of 1992 rpm. 2g of potassium feldspar mineral sample (particle size -0.074mm to +0.038mm) was added to the flotation cell and mixed with 40mL of deionized water. NaOH was added sequentially as a pH adjuster and flotation collector, with a 2-minute interval between each operation. Following this, foaming was performed for 1 minute, followed by skimming for 2 minutes. The resulting upper foam product and the product in the cell were dried and weighed in petri dishes, and the flotation recovery rate was calculated. Each experiment was repeated three times. The pH, collector type, and dosage were adjusted according to the specific experimental requirements. The experimental results are shown in Tables 3 and 4.

[0061] Table 3. Results of flotation performance tests (%) of dodecylamine and N-dodecyl-β-amino-1-methylpropionate cyclohexyl ester on pure potassium feldspar minerals

[0062]

[0063] Table 4. Results of the experimental study on the effect of dodecylamine and N-dodecyl-β-amino-1-methylpropionate dosage on the flotation performance of pure potassium feldspar minerals (%)

[0064]

[0065] Example 3

[0066] A comparison of the flotation performance of N-dodecyl-β-amino-1-methylpropionate cyclohexyl ester and dodecylamine in artificially mixed quartz and potassium feldspar minerals with different mass ratios was conducted, including the following steps:

[0067] Flotation experiments were conducted on an XFG flotation machine at Jilin Exploration Machinery Plant, using artificially mixed minerals of different proportions of quartz and potassium feldspar. The impeller speed of the flotation machine was 1992 rpm. 4 g of the mixed mineral sample (particle size -0.074 mm to +0.038 mm) was added to the flotation cell and mixed with 80 mL of deionized water. NaOH was added sequentially as a pH adjuster and flotation collector, with a 2-minute interval between each operation, followed by 1 minute of foaming and 2 minutes of skimming. The resulting upper foam product and the product in the cell were dried and weighed in petri dishes, and the flotation recovery rate was calculated. Each experiment was repeated three times.

[0068] Furthermore, the flotation process, pH, and the type and dosage of collector were adjusted according to the corresponding experimental requirements. The experimental results are shown in Tables 5, 6, and 7.

[0069] Table 5. Comparison of flotation performance (%) of N-dodecyl-β-amino-1-methylpropionate cyclohexyl ore with different mass ratios of artificially mixed quartz and potassium feldspar.

[0070]

[0071] Table 6. Flotation results (%) of a 1:9 artificial mixture of potassium feldspar and quartz after one refining step of N-dodecyl-β-amino-1-methylpropionate cyclohexyl ester.

[0072]

[0073] Note: The collector dosage during the fine selection process is 65 mg / L, the pH is 11, and the impeller speed of the flotation machine is 1992 rpm.

[0074] Table 7 Comparison of flotation performance of dodecylamine with different mass ratios of artificially mixed quartz and potassium feldspar ores (%)

[0075]

[0076] In summary, although dodecylamine exhibits strong recovery rates in mixed potassium feldspar and quartz minerals with varying quartz purities, the SiO2 and K2O levels after flotation show almost no change compared to the initial grades, indicating that dodecylamine has virtually no selectivity for quartz. However, under highly alkaline conditions, when the quartz content in the mixed potassium feldspar and quartz minerals ranges from 30 wt% (mass ratio 7:3) to 90 wt%, the SiO2 level after flotation shows a significant upward trend compared to the initial SiO2, while the K2O level shows a significant downward trend compared to the initial K2O. This indicates that N-dodecyl-β-amino-1-methylpropionic acid cyclohexyl ester has good selectivity for medium to high quartz content minerals. However, the quartz recovery rate is low when the quartz content is 30 wt%, but it significantly improves when the quartz content is 50-90 wt%. Especially when the quartz content is 70-90 wt%, the recovery rate can reach over 80% after only one roughing stage, achieving a simultaneous improvement in both recovery rate and selectivity. Furthermore, when the quartz content is high, the grade of the quartz can be further improved through fine selection, demonstrating its good selective collection performance and applicability to the purification of various quartz products.

Claims

1. A quartz collector, characterized in that: The quartz collector, used for flotation separation of quartz and potassium feldspar minerals, has the following structural formula: ； Formula 1; Wherein, R1 is selected from alkyl groups of C8 to C20, and R2 is selected from H or methyl.

2. The quartz collector according to claim 1, characterized in that: R1 is a C8-C12 alkyl group, and R2 is a methyl group; the quartz content in the mineral is 30-90 wt%.

3. A method for preparing a quartz collector according to claim 1 or 2, characterized in that: After dissolving R1-NH2 in an alkanoic solvent, a cyclohexyl ester compound of formula 2 is added to carry out an addition reaction to obtain the product. ； Formula 2; Wherein, R1 is selected from alkyl groups of C8 to C20, and R2 is selected from H or methyl.

4. The method for preparing a quartz collector according to claim 3, characterized in that: The cyclohexyl ester compound is cyclohexyl methacrylate; R1-NH2 is dodecylamine.

5. The method for preparing a quartz collector according to claim 3, characterized in that: The molar ratio of R1-NH2 to the cyclohexyl ester compound of formula 2 is 1:(1.1~5); The alkanol solvent is selected from at least one of methanol, ethanol, propanol, and ethylene glycol.

6. The method for preparing a quartz collector according to claim 5, characterized in that: The amount of the alkanoic solvent used is 4 to 8 times the mass of R1-NH2.

7. The method for preparing a quartz collector according to claim 4, characterized in that: The conditions for the addition reaction are: temperature 65~70℃ and time 6~15h.

8. The application of the quartz collector according to claim 1 or 2, characterized in that: It is used for flotation separation of quartz and potassium feldspar minerals, and the quartz content in the minerals is 30~90wt%.

9. The application of the quartz collector according to claim 8, characterized in that: The application process is as follows: the raw ore containing both quartz and potassium feldspar minerals is adjusted to an alkaline pH to obtain a slurry; flotation reagents, including the quartz collector of Formula 1, are added to the slurry for flotation to obtain quartz froth concentrate and potassium feldspar tailings.

10. The application of the quartz collector according to claim 9, characterized in that: The flotation process also includes at least one fine cleaning step; the pH is 7-12; the amount of quartz collector used relative to the amount of raw ore is 5-200 mg / L; and the quartz content in the mineral is 70-90 wt%.

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