Amphoteric collector for separating quartz and potassium feldspar by flotation and preparation method and application thereof

Abstract

The application discloses a kind of amphoteric collector for separating quartz and potassium feldspar by flotation and a preparation method and application thereof, belong to the field of flotation reagent, the amphoteric quartz collector has the following structural formula, wherein R1 is selected from C8-C20 alkyl, R2, R3 are independently selected from H or methyl;R4 is selected from C1-C4 alkyl.The collector shows good selectivity and high recovery rate for quartz mineral in the mixed mineral of quartz content of 30-70wt% and potassium feldspar, can selectively collect quartz mineral particles, so as to realize the increase of SiO2 grade in quartz feldspar mixed ore, reach the purpose of improving mineral purity.

Description

TECHNICAL FIELD

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

[0002] The traditional flotation method of quartz and potassium feldspar mainly relies on the separation of the two by adjusting the pH value and using specific collectors. However, the existing reagent system has many limitations. For example, although the fatty acid collector used in acid flotation has good collecting effect on quartz, it has high acid consumption, serious corrosion to equipment and is not environmentally friendly; the anionic and cationic surfactants commonly used in alkali flotation have lower toxicity, but the preparation of reagents under alkaline conditions is complex and has high requirements for water quality. In addition, the selectivity and adaptability of traditional flotation reagents still need to be improved, especially when dealing with complex ores, it is difficult to achieve efficient separation. The most common method for flotation separation of quartz and feldspar is hydrofluoric acid method, but hydrofluoric acid is not only toxic, but also not environmentally friendly, and the risk coefficient of hydrofluoric acid in use is extremely high. In recent years, many researchers have devoted to developing a fluorine-free separation system.

[0003] In recent years, significant progress has been made in the research of flotation reagents. Researchers have devoted to developing new reagents to improve flotation efficiency, reduce cost and reduce environmental impact. In the prior art, on the one hand, the use of cationic surfactants and anionic surfactants in combination can achieve the separation of quartz and potassium feldspar in a wider pH range, while reducing the amount of single reagent. For example, Chinese patent application CN119327623A discloses a collector that can be used for quartz positive and negative flotation, which realizes the flotation separation of feldspar and quartz by combining anionic and cationic collectors in a specific ratio and modifying the surface of quartz under strong alkaline conditions.

[0004] On the other hand, a series of collectors with better performance have been developed by modifying traditional reagents. For example, Chinese patent application CN116943869A discloses a microparticle feldspar reverse flotation combined collector and a method for feldspar reverse flotation of quartz-containing ore powder, which uses a combined collector of modified sodium oleate and modified sodium dodecyl sulfonate, has stronger collecting ability for feldspar containing quartz ore powder, and higher recovery rate of quartz. However, this method requires modification of two collectors at the same time, and the flotation process is complex, and the separation effect of quartz and feldspar is limited.

[0005] Therefore, there is an urgent need for an environmentally friendly collector that can be used for flotation separation of quartz and feldspar under fluorine-free and acid-free conditions, and has simple synthesis steps, low price and good flotation effect, which is of great significance for the comprehensive recovery and utilization of non-metallic resources in tailings. SUMMARY

[0006] To overcome the problems in the prior art, a first object of the present application is to provide an amphoteric quartz collector for separating quartz and potassium feldspar, which exhibits a dual effect of good selectivity and high recovery rate for quartz minerals in a mixed mineral with a quartz content of 30-70wt% and potassium feldspar.

[0007] A second object of the present application is to provide a preparation method of the amphoteric quartz collector, which can be prepared by only one step reaction, and has the advantages of simple steps and easily available raw materials.

[0008] A third object of the present application is to provide an application of the amphoteric quartz collector, which can separate quartz and feldspar, two minerals with small differences in surface properties, under fluorine-free and acid-free conditions without compounding with other collectors, and has the advantage of high flotation efficiency.

[0009] Through years of intensive research and practical application of mineral flotation, it is found that due to the unevenly embedded fine or micro-fine particles of quartz in the ore, the small difference in surface properties between quartz and feldspar gangue minerals, and the poor environmental friendliness of the flotation slurry, the efficiency and recovery rate of quartz and feldspar beneficiation are seriously affected, and the preparation of the new reagent requires multiple synthesis steps. To solve this technical problem, the present application provides an amphoteric quartz collector for separating quartz and potassium feldspar minerals, which has the following structural formula:

[0010] ;

[0011] Formula 1;

[0012] wherein R1 is selected from C8-C20 alkyl, R2 and R3 are independently selected from H or methyl; and R4 is selected from C1-C4 alkyl.

[0013] As a preferred scheme, the content of quartz in the mineral is 30-70wt%.

[0014] The amino group and ester group contained in the molecular structure of the collector can synergistically change the activity and electronegativity of the collector, and the special spatial structure of the ester group can produce different steric hindrance effects with the two minerals of quartz and potassium feldspar which belong to silicates, thereby improving the selectivity of the reagent for medium content quartz. In addition, the long-chain alkyl group in the collector as a strong hydrophobic group can effectively enhance the hydrophobicity of the mineral surface, promote bubble adhesion and flotation efficiency, and synergistically with other alkyl groups in the molecular structure to achieve a higher recovery rate when the content of quartz is 30-70wt%.

[0015] As a preferred solution, R1 is C8-C12 alkyl, and R2, R3 and R4 are all methyl. It is found through experiments that when further preferred groups are used, more excellent selectivity and recovery rate effects can be exhibited.

[0016] As a preferred solution, the content of quartz in the mineral is 30-50 wt%, and it is found through experiments that the collector of the present application has better selectivity and recovery rate effects on quartz within this range.

[0017] The present application also provides a preparation method of the amphoteric quartz collector, which comprises dissolving R1-NH2 in an alkanol solvent and then adding an ester compound of formula 2 for addition reaction, to obtain the product.

[0018] ;

[0019] Formula 2;

[0020] wherein R1 is selected from C8-C20 alkyl, R2 and R3 are independently selected from H or methyl, and R4 is selected from C1-C4 alkyl.

[0021] The preparation method of the present application is simple, and the product with high yield can be obtained through only one step of addition reaction, thereby avoiding the risk of reducing the purity of the product due to the introduction of impurities in multi-step reactions.

[0022] As a preferred solution, the ester compound is 3,3-dimethyl methacrylate.

[0023] As a preferred solution, R1-NH2 is octylamine or dodecylamine. Further, R1-NH2 is dodecylamine.

[0024] As a preferred solution, the molar ratio of R1-NH2 to the ester compound of formula 2 is 1:(1-10). Within the preferred molar ratio range of the present application, the excess of the ester compound over R1-NH2 is conducive to ensuring the sufficient combination of the long-chain amine hydrophobic functional group and ensuring the performance of the collector. Further, the molar ratio of R1-NH2 to the ester compound of formula 2 is (1.1-1.2):1.

[0025] As a preferred solution, 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.

[0026] As a preferred solution, the amount of the alkanol solvent is 1-10 times the mass of R1-NH2.

[0027] As a preferred solution, the concentration of the alkanol solvent is 40-99.9wt%, and further preferably 90-99.8wt%, which is helpful to further improve the addition reaction, control the product purity of the amphoteric quartz collector, and further improve the collecting performance on fine-grained minerals. Further, the temperature for dissolving R1-NH2 in the alkanol solvent is 20-55℃, and the time is 3-15h.

[0028] As a preferred solution, the conditions for the addition reaction are: temperature 55-70℃, and time 3-15h. Within the reaction temperature and time range of the present application, it is helpful to obtain the compound of formula 1 with high yield and high purity. Further, the temperature is 60-65℃, and the time is 4-8h.

[0029] As a preferred solution, the purity of R1-NH2 needs to be greater than 90wt%, which is helpful to prepare the amphoteric quartz collector with better collecting performance under the raw material with the purity.

[0030] The present application allows the amphoteric quartz collector to be prepared by using the existing method.

[0031] The present application finally provides an application of the amphoteric quartz collector, which is used for the flotation separation of quartz and potassium feldspar minerals, and the content of quartz in the minerals is 30-70wt%.

[0032] As a preferred solution, the process of the application is: after the raw ore containing quartz and potassium feldspar minerals is slurried to be alkaline, a slurry is obtained; the flotation reagent containing the amphoteric quartz collector of formula 1 is added to the slurry for flotation, and then quartz froth concentrate and potassium feldspar tailings are obtained.

[0033] The collector of the present application can separate quartz and feldspar minerals with small surface property difference under the conditions of no fluorine and no acid in one roughing without compounding with other collectors, which has the advantages of high flotation efficiency.

[0034] As a preferred solution, the pH is 7-11. Under alkaline conditions, the amino group in the present application is easy to form positively charged amine ions, and the silicate mineral has a negative surface under alkaline conditions. These positively charged ions can more easily be electrostatically adsorbed on the negatively charged sites on the mineral surface. Within the pH range of the present application, the collector shows good collecting effect on quartz, and within this pH range, the use of appropriate amount of collector can play a role in selective separation. Further, when the pH is 10-11, the collector of the present application shows high selectivity for quartz minerals.

[0035] As a preferred scheme, the amount of the amphoteric quartz collector is 5-400 mg / L relative to the amount of the raw ore, and the content of quartz in the mineral is 30-50 wt%. The amount of the amphoteric quartz collector of the present application can produce a certain collecting effect on quartz minerals and potassium feldspar, and with the increase of the amount of the collector, the floating rate of the two minerals increases, and when the amount of the collector is further selected to be 20-22.5 mg / L, the best selective collecting effect is produced. Of course, if it is within the best pH range, it is not limited.

[0036] As a preferred scheme, the amphoteric quartz collector can be used in combination with other collectors to further improve the recovery rate of separation, such as dodecylamine; and a foaming agent or the like can be added to promote the flotation process.

[0037] As a preferred scheme, the raw ore containing quartz and potassium feldspar minerals needs to be ground to a particle size of 0.074 mm of 60-100 wt% before being thickened by using a pH regulator. Further, the pH regulator is at least one of sodium hydroxide and sodium carbonate.

[0038] As a preferred scheme, the flotation further includes at least one cleaning. It is found through experiments that on the basis of roughing, at least one cleaning is added to further improve the grade of SiO2 in the concentrate, reduce the grade of K2O, further improve the selectivity, and reduce the loss of the whole mineral through middlings.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] (1) The present application provides an original amphoteric quartz collector which is applied to the flotation process of quartz and potassium feldspar mixed ore, and is especially suitable for selective flotation of quartz content of 30-70 wt%. The collector can selectively enhance the hydrophobicity of the surface of fine useful medium quartz concentration particles, and under the synergistic effect of specific functional groups and molecular structures, the collector selectively acts on quartz to enhance the hydrophobicity of the surface of quartz and improve the recovery rate, and is a high-efficiency selective collector for quartz.

[0041] (2) The amphoteric quartz collector of the present application can realize the separation of quartz and feldspar which have small differences in surface properties under the conditions of no fluorine and no acid without compounding with other collectors, and shows good selectivity in the mixed mineral of quartz content of 30-70 wt% and potassium feldspar, and the recovery rate can reach more than 72% after only one roughing.

[0042] (3) The preparation method of the amphoteric quartz collector of the present application can be obtained by only one step reaction, and has the advantages of simple steps and easy-to-obtain raw materials.

[0043] (4) The amphoteric quartz collector of the present application can meet the application of industrial production, and the amphoteric quartz collector realizes selective adsorption on quartz through the synergistic effect of the double functional groups, has higher quartz recovery rate and lower impurity inclusions compared with ordinary collectors, and is friendly to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The chemical synthesis formula of the amphoteric quartz collector prepared for the embodiment of the present application.

[0045] Figure 2 The flotation process flow chart of the amphoteric quartz collector of embodiment 3 of the present application.

[0046] Figure 3 The flotation process flow chart of the amphoteric quartz collector of embodiment 4 of the present application.

[0047] Figure 4 The nuclear magnetic resonance hydrogen spectrum of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester prepared for the embodiment of the present application.

[0048] Figure 5 The nuclear magnetic resonance carbon spectrum of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester prepared for the embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0050] Unless otherwise defined, all the professional terms used in the following are the same as the meanings commonly understood by those skilled in the art. The professional terms used in the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the scope of protection of the present application.

[0051] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by the existing method.

[0052] When the N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester (DAMD) amphoteric quartz collector is applied to quartz flotation, the flotation process conditions are as follows: the dosage of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester is between 5 mg / L and 400 mg / L, and the ore particle size is 60-100 wt% of -0.074 mm.

[0053] When the N-dodecyl-β-amino-1-1-dimethylpropionate amphoteric quartz collector is applied to potassium feldspar flotation, the flotation process conditions are as follows: the amount of N-dodecyl-β-amino-1-1-dimethylpropionate is between 5 mg / L and 400 mg / L, and the ore particle size is -0.074 mm, accounting for 60 to 100 wt%.

[0054] In the following examples and comparative examples, the amphoteric quartz collectors were obtained by the following methods:

[0055] Methyl N-dodecyl-β-amino-1,1-dimethylpropionate was synthesized from dodecylamine and methyl 3,3-dimethacrylate. 100 mL of methanol (99.8% purity) 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, 0.11 mol of methyl 3,3-dimethacrylate was slowly added dropwise, and the mixture was heated in a water bath to 65 °C with stirring under reflux for 6 hours. After the reaction was complete, methanol (which can be recycled) and low-boiling substances were removed from the reaction product using a rotary evaporator to obtain the final product. The resulting amphoteric quartz collector has the following structural formula (Formula 3):

[0056] ;

[0057] Formula 3.

[0058] The nuclear magnetic resonance spectrum of DAMD and the corresponding chemical shift (δ) assignments are as follows: Figure 4 and Figure 5 As shown, 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 3.56 (s, 3H), 3.17(s, 1H), 2.42 (t, J = 6.7 Hz, 2H), 2.10 (d, J = 1.3 Hz, 2H), 1.32 (t, J = 6.7Hz, 2H), 1.25 (s, 18H), 1.05 (s, 6H), 0.88- 0.84 (m, 3H). 13 The δ values ​​of each C atom and their assignments in the C-NMR spectrum are as follows: 13 C NMR (101 MHz, DMSO) δ 171.70, 51.69, 50.79, 48.50, 44.05, 31.20, 30.39, 28.90, 28.60, 26.92, 26.70, 21.98, 13.81.

[0059] Example 1

[0060] Comparative flotation of quartz pure mineral with N-dodecyl-β-amino-1-1- dimethylpropionic acid methyl ester and dodecylamine, including the following steps:

[0061] Single mineral flotation experiments were performed on a XFG flotation machine from Jilin Prospecting Machinery Plant with an impeller speed of 1992 rpm. 2 g of quartz mineral sample (-0.074 mm to +0.038 mm in size) was added to the flotation cell and mixed with 40 mL of deionized water. NaOH was added as a pH adjuster and the above-mentioned amphoteric quartz collector was added sequentially, with a 2 min interval between each operation. After 1 min of frothing, the froth was scraped for 2 min. The resulting upper froth product and the in-cell product were dried and weighed in a petri dish, and the flotation recovery was calculated. Each test was repeated 3 times. The pH and the type and amount of collector were adjusted according to the corresponding experimental requirements. The results are shown in Tables 1 and 2.

[0062] Table 1 Comparative flotation of quartz pure mineral with N-dodecyl-β-amino-1-1- dimethylpropionic acid methyl ester and dodecylamine (%)

[0063]

[0064] Table 2 Comparative flotation of quartz pure mineral with N-dodecyl-β-amino-1-1- dimethylpropionic acid methyl ester and dodecylamine (%)

[0065]

[0066] Example 2

[0067] Comparative flotation of potassium feldspar pure mineral with N-dodecyl-β-amino-1-1- dimethylpropionic acid methyl ester and dodecylamine, including the following steps:

[0068] Single mineral flotation experiments were performed on a XFG flotation machine from Jilin Prospecting Machinery Plant with an impeller speed of 1992 rpm. 2 g of potassium feldspar mineral sample (-0.074 mm to +0.038 mm in size) was added to the flotation cell and mixed with 40 mL of deionized water. NaOH was added as a pH adjuster and the above-mentioned amphoteric quartz collector was added sequentially, with a 2 min interval between each operation. After 1 min of frothing, the froth was scraped for 2 min. The resulting upper froth product and the in-cell product were dried and weighed in a petri dish, and the flotation recovery was calculated. Each test was repeated 3 times. The pH and the type and amount of collector were adjusted according to the corresponding experimental requirements. The results are shown in Tables 3 and 4.

[0069] Table 3 The results of the flotation performance test of dodecylamine and N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester on potassium feldspar pure mineral (%)

[0070]

[0071] Table 4 The results of the flotation performance test of dodecylamine and N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester on potassium feldspar pure mineral (%)

[0072]

[0073] Example 3

[0074] The flotation performance comparison of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester and dodecylamine on the artificial mixed mineral of quartz and potassium feldspar with different mass ratios.

[0075] The flotation experiment of the artificial mixed mineral of quartz and potassium feldspar with different mass ratios was carried out on the XFG flotation machine of Jilin Exploration Machinery Factory, and the impeller speed of the flotation machine was 1992 rpm.

[0076] 4 g of the mixed mineral sample (particle size of -0.074 mm to +0.038 mm) was added into the flotation tank and mixed and stirred with 80 mL of deionized water. NaOH was added as a pH adjuster and a flotation collector in sequence, and each operation interval was 2 min, followed by foaming for 1 min and scraping for 2 min. The obtained upper foam product and the tank product were dried and weighed in a culture dish, and the flotation recovery rate was calculated. Each test was repeated 3 times. And according to the corresponding experimental requirements, the pH and the type and amount of the collector were adjusted. The experimental results are shown in Tables 5 and 6.

[0077] Table 5 The results of the flotation performance comparison of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester on the artificial mixed mineral of potassium feldspar and quartz with different mass ratios (%)

[0078]

[0079] Table 6 The results of the flotation performance comparison of dodecylamine on the artificial mixed mineral of potassium feldspar and quartz with different mass ratios (%)

[0080]

[0081] Comprehensive comparison, although the dodecylamine recovery rate in the mixed minerals of potassium feldspar and quartz is strong at different quartz purity, but the SiO2 and K2O after flotation has little change compared with the initial grade, which shows that dodecylamine collects all the potassium feldspar up while collecting quartz, which shows that dodecylamine has little selectivity for quartz, while N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester in the mixed minerals of potassium feldspar and quartz under high alkaline conditions, when the quartz content is 30wt% (mass ratio 7:3)~70wt% (mass ratio 3:7), the grade of SiO2 after flotation compared with the initial SiO2 shows an upward trend, while the grade of K2O after flotation compared with the initial K2O shows a downward trend, which shows that N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester has good selectivity for quartz in the range of quartz and potassium feldspar, and the recovery rate of quartz can be more than 72%. But when the quartz content is 90wt%, N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester cannot realize selective collection of quartz.

[0082] Example 4

[0083] The results of the first cleaning of the artificial mixed ore of quartz and potassium feldspar with different mass ratios of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester.

[0084] In this experiment, after the first rough flotation, in order to further improve the grade of the concentrate, a first cleaning operation was carried out, the impeller speed of the flotation machine was 1992 rpm, the dosage of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester and the flotation pH were the same as in Example 3. In the cleaning process, the concentrate was floated again to further improve the grade of quartz and reduce the content of potassium feldspar. The cleaning operation effectively improved the SiO2 grade of the concentrate, and ultimately obtained a concentrate with higher grade, and through the middlings reduced the overall loss, the results are shown in Table 7.

[0085] Table 7 The cleaning results of N-dodecyl-β-amino-1-1-dimethylpropionic acid methyl ester in the artificial mixed ore of potassium feldspar and quartz with different mass ratios (%)

[0086] .

Claims

1. The application of an amphoteric quartz collector, characterized in that: This material is used for flotation separation of quartz and potassium feldspar minerals, wherein the quartz content in the minerals is 30-50 wt%; and the pH of the flotation separation is 10-11. The amphoteric quartz collector has the following structural formula: Where R1 is C 12 R2, R3 and R4 are all methyl groups.

2. The application of the amphoteric quartz collector according to claim 1, characterized in that: The amphoteric quartz collector is prepared by dissolving dodecylamine in an alkanol solvent, then adding methyl 3,3-dimethacrylate for an addition reaction.

3. The application of the amphoteric quartz collector according to claim 2, characterized in that: The molar ratio of dodecylamine to methyl 3,3-dimethacrylate is 1:(1-10); The alkanol solvent is selected from at least one of methanol, ethanol, propanol, and ethylene glycol.

4. The application of the amphoteric quartz collector according to claim 3, characterized in that: The amount of the alkanoic solvent used is 1 to 10 times the mass of methyl 3,3-dimethacrylate.

5. The application of the amphoteric quartz collector according to claim 3, characterized in that: The conditions for the addition reaction are: temperature of 55–70°C and time of 3–15 h.

6. The application of the amphoteric quartz collector according to claim 5, characterized in that: The application process is as follows: the raw ore containing both quartz and potassium feldspar minerals is slurried to a pH of 10-11 to obtain a slurry; flotation reagents, including the amphoteric quartz collector of Formula 1, are added to the slurry for flotation to obtain quartz froth concentrate and potassium feldspar tailings.

7. The application of the amphoteric quartz collector according to claim 6, characterized in that: The amount of the amphoteric quartz collector used relative to the amount of raw ore is 5-400 mg / L.

Images