Combined collector for reverse flotation of micro-feldspar and reverse flotation method for feldspar containing quartz ore powder

Abstract

The present invention discloses a micro-particle feldspar reverse flotation combined collector, comprising modified sodium oleate and modified sodium dodecyl sulfate; the present invention also discloses a quartz ore powder-containing feldspar reverse flotation combined collector, the method comprising preparing a micro-particle feldspar reverse flotation combined collector with a mass concentration of 10%-20%; removing large-particle impurities of 400-500 mesh and fine-particle mud of 40-140 mesh in the quartz ore powder to obtain pretreated quartz ore powder; pouring the pretreated quartz ore powder into a flotation tank and adding deionized water to form a slurry; adding a pH adjuster to the slurry to adjust the pH value to 11-12, then adding an inhibitor, a micro-particle feldspar reverse flotation combined collector and a frother under stirring conditions, and sequentially subjecting the quartz concentrate to reverse flotation roughing, at least two reverse flotation cleanings and at least two scavengings. The micro-particle feldspar reverse flotation combined collector provided by the present invention has a stronger capture ability for feldspar containing quartz ore powder and a higher recovery rate of quartz.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing engineering, and in particular relates to a combined collector for reverse flotation of micro-particle feldspar and a reverse flotation method for feldspar containing quartz ore powder. Background Art

[0002] Quartz, a vitreous mineral composed of silicon dioxide, is an important industrial raw material, widely used in glass, casting, ceramics and refractories, metallurgy, construction, chemicals, plastics, rubber, abrasives, and other industries. However, quartz often coexists with feldspar, or as a gangue mineral, alongside various useful minerals. Effectively separating the two minerals not only lays the foundation for their development and utilization, but also increases economic efficiency and achieves energy conservation and emission reduction for mines that use quartz and feldspar as tailings.

[0003] The most common flotation separation method for quartz and feldspar is hydrofluoric acid. However, hydrofluoric acid is not only toxic and environmentally unfriendly, but also extremely hazardous during use. In recent years, many researchers have been dedicated to developing fluorine-free separation systems, such as the alkaline puffite method. For minerals with high feldspar content and complex feldspar species, the alkaline puffite method is most effective, with low product intercalation and the ability to easily produce a qualified concentrate. Therefore, the alkaline puffite method holds great promise.

[0004] Currently, the collectors used in the alkaline puffite process are primarily single agents, such as sodium oleate. These single agents suffer from poor selectivity, a simple structure, high dosage, and difficulty dispersing at low temperatures, leading to reagent waste and increased reverse flotation costs. While combined collectors, such as sodium oleate and octadecylamine, currently used in the alkaline puffite process can address the issue of poor selectivity, they also result in low concentrate recoveries.

[0005] Therefore, there is an urgent need to develop an efficient collector and feldspar reverse flotation method suitable for feldspar reverse flotation, so as to facilitate the efficient utilization and research of difficult-to-select complex quartz ore resources. Summary of the Invention

[0006] In view of the defects and shortcomings of the existing technology, the purpose of the present invention is to provide a combined collector for the reverse flotation of micro-feldspar, a preparation method and an application thereof, so as to solve the technical problem of poor selectivity of a single collector for micro-feldspar in the feldspar reverse flotation process in the existing technology.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A combined collector for reverse flotation of fine feldspar comprises modified sodium oleate and modified sodium dodecylsulfonate. The simplified structural formula of the modified sodium oleate is:

[0009]

[0010] The structural formula of the modified sodium lauryl sulfonate is:

[0011]

[0012] Where n+m=10.

[0013] The present invention also has the following technical features:

[0014] Specifically, the mass ratio of the modified sodium oleate to the modified sodium dodecylsulfonate is 1:(0.5-1.5).

[0015] Furthermore, the preparation of the modified sodium oleate comprises the following steps:

[0016] Step 1: Dissolve the formulated amount of sodium oleate in an acetone solution in a cold water bath, and then introduce sulfur trioxide gas to obtain a mixed liquid A;

[0017] Step 2: adding a formula amount of sodium hydroxide to the mixed liquid A to obtain a mixed liquid B, and drying the mixed liquid B to obtain an intermediate product C;

[0018] Step 3: dissolving the intermediate product C in the formula amount in methanol to generate a mixed liquid D under the action of a catalyst, and drying the mixed liquid D;

[0019] The temperature of the cold water bath is 50° C. to 80° C., the mass ratio of the sodium oleate, sulfur trioxide, and sodium hydroxide is 1:(2-3):1, the mass ratio of the sodium oleate, acetone, and methanol is 1:(15-20):(15-20), and the catalyst is concentrated sulfuric acid.

[0020] Furthermore, the preparation of the modified sodium dodecyl sulfate comprises: introducing chlorine gas into sodium dodecyl sulfate at a temperature of 280° C. to 320° C. and a pressure of 5 to 7 MPa to generate sodium chlorododecyl sulfate; adding sodium hydroxide to an ethanol solution of the sodium chlorododecyl sulfate and heating the solution to 150° C. to 180° C. to induce an elimination reaction to introduce a carbon-carbon double bond, thereby obtaining a mixed liquid E; and reacting the mixed liquid E with water in the presence of a catalyst to obtain the modified sodium dodecyl sulfate;

[0021] The mass ratio of the sodium dodecylsulfonate, chlorine, ethanol and sodium hydroxide is 1:1:(8-10):1, and the catalyst is concentrated sulfuric acid.

[0022] Furthermore, the method adopts the above-mentioned micro-feldspar reverse flotation combined collector.

[0023] Furthermore, the quartz-containing mineral powder is the tailings of quartz vein-type gold mine.

[0024] Furthermore, the method comprises the following steps:

[0025] Step S1, preparing a combined collector for reverse flotation of fine feldspar with a mass concentration of 10% to 20%;

[0026] Step S2, removing large impurities of 400-500 mesh and fine mud particles of 40-140 mesh from the quartz-containing ore powder to obtain pretreated quartz-containing ore powder;

[0027] Step S3: pouring the pretreated quartz-containing ore powder into a flotation tank and adding deionized water to form a slurry; adding a pH adjuster to the slurry to adjust the pH value to 11-12, and then adding an inhibitor, the micro-feldspar reverse flotation combined collector prepared in step S1, and a frother under stirring conditions, and sequentially performing reverse flotation roughing, at least two reverse flotation cleanings, and at least two scavengings to obtain a quartz concentrate.

[0028] Furthermore, in step S3, the pH adjuster is sodium hydroxide; the inhibitor is sodium hexametaphosphate; and the foaming agent is No. 2 oil;

[0029] For each ton of mineral powder, the amount of sodium hexametaphosphate added is 100g to 200g; the amount of micro-feldspar reverse flotation combined collector added is 150g to 300g; and the amount of No. 2 oil added is 20g to 40g.

[0030] Furthermore, the mass concentration of the ore pulp is 20% to 40%, the stirring speed of the stirring condition is 1500 to 2000 rpm, and the reverse flotation roughing time is 5 to 7 minutes.

[0031] Furthermore, the time for each reverse flotation selection is 4 to 8 minutes, and the time for each sweep selection is 4 to 6 minutes;

[0032] In the step 3, the amount of the feldspar reverse flotation combined collector added is calculated based on the mass of the ore powder in the slurry, and the amount used per ton is 150 to 300 g.

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

[0034] (1) The micro-feldspar reverse flotation combined collector prepared by the method of the present invention is composed of modified sodium oleate and modified sodium dodecylsulfonate. Compared with the unmodified combined collector, the micro-feldspar reverse flotation combined collector provided by the present invention has a stronger ability to capture feldspar containing quartz ore powder and a higher recovery rate of quartz.

[0035] (2) Due to the introduction of sulfate into the combined collector for reverse flotation of micro-feldspar provided by the present invention, the modified sodium oleate has two active functional groups that can react with the surface of feldspar, thereby significantly improving the flotation effect and reducing the amount of collector used.

[0036] (3) In the feldspar reverse flotation combined collector provided by the present invention, the introduction of ether groups in the modified sodium oleate enhances the polar groups in the molecule, making the collector more easily dispersed in the ore pulp and increasing its solubility; the ether oxygen atoms can also react with Al ions and adsorb on the feldspar surface, thereby enhancing the collection ability; sodium dodecyl sulfate is modified to introduce hydroxyl groups, which increases its dispersibility and solubility in the ore pulp, thereby enhancing its collection ability.

[0037] (4) The method of the present invention can be used to prepare a combined collector for reverse flotation of micro-feldspar with better collecting ability, and the method of the invention is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a process flow chart of feldspar reverse flotation of the present invention;

[0039] Figure 2 This is the laser particle size analysis diagram of mineral powder;

[0040] Figure 3 is the infrared spectrum of modified sodium oleate;

[0041] Figure 4 This is the infrared spectrum of modified sodium dodecyl sulfate.

[0042] The technical solution of the present invention is further described below in conjunction with embodiments. DETAILED DESCRIPTION

[0043] In accordance with the above technical solution, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0044] The inventive concept of the present invention is to provide a feldspar reverse flotation combined collector with high selectivity to reduce the impact of the collector adsorbed on the pre-selected mineral on the reverse flotation operation, enhance the selectivity of sodium oleate adsorption, increase the reverse flotation recovery rate, and improve the sorting index.

[0045] In the feldspar reverse flotation combined collector provided by the present invention, sulfonic acid groups and ether bonds are introduced into the modified sodium oleate. The sulfonic acid groups primarily function by forming cyclic chelates with metal ions to enhance the capture ability of the modified sodium oleate. The ether bonds, in addition to improving the dispersibility of the modified sodium oleate, can also interact with aluminum ions on the feldspar surface, adsorbing them and thereby enhancing the capture ability. Hydroxyl groups are introduced into sodium dodecyl sulfate to significantly enhance its hydrophilicity, and the dispersion of the modified sodium dodecyl sulfate in the ore pulp is significantly improved. After modifying the sodium oleate and sodium dodecyl sulfate, a novel feldspar reverse flotation combined collector with strong capture ability, high dispersibility, and good selectivity is prepared.

[0046] In summary, the present invention provides a combined collector for reverse flotation of fine feldspar, comprising modified sodium oleate and modified sodium dodecylsulfonate. The structural formula of the modified sodium oleate is:

[0047]

[0048] The structural formula of the modified sodium lauryl sulfonate is:

[0049]

[0050] Where n+m=10.

[0051] Preferably, the mass ratio of the modified sodium oleate to the modified sodium dodecylsulfonate is 1:(0.5-1.5).

[0052] Preferably, the preparation of the modified sodium oleate comprises the following steps:

[0053] Step 1: Dissolve the formulated amount of sodium oleate in an acetone solution in a cold water bath, and then introduce sulfur trioxide gas to obtain a mixed liquid A;

[0054] Step 2: adding a formula amount of sodium hydroxide to the mixed liquid A to obtain a mixed liquid B, and drying the mixed liquid B to obtain an intermediate product C;

[0055] Step 3: dissolving the intermediate product C in the formula amount in methanol to generate a mixed liquid D under the action of a catalyst, and drying the mixed liquid D;

[0056] The cold water bath temperature is 50° C. to 80° C., the mass ratio of sodium oleate, sulfur trioxide, and sodium hydroxide is 1:(2-3):1, the mass ratio of sodium oleate, acetone, and methanol is 1:(15-20):(15-20), and the catalyst is concentrated sulfuric acid.

[0057] Preferably, the preparation of the modified sodium dodecyl sulfate comprises: introducing chlorine gas into the sodium dodecyl sulfate at a temperature of 280° C. to 320° C. and a pressure of 5 to 7 MPa, replacing hydrogen atoms with chlorine free radicals, and generating a chlorination reaction to produce sodium chlorododecyl sulfate; adding sodium hydroxide to an ethanol solution of the sodium chlorododecyl sulfate and heating to 150° C. to 180° C. to generate an elimination reaction to introduce a carbon-carbon double bond, thereby obtaining a mixed liquid E; and reacting the mixed liquid E with water in the presence of a catalyst to obtain the modified sodium dodecyl sulfate;

[0058] The mass ratio of sodium dodecylsulfonate, chlorine, ethanol and sodium hydroxide is 1:1:(8-10):1, and the catalyst is concentrated sulfuric acid.

[0059] The present invention also protects a method for reverse flotation of feldspar containing quartz ore powder, which adopts the above-mentioned micro-particle feldspar reverse flotation combined collector.

[0060] The quartz-containing mineral powder is the tailings of quartz vein-type gold mine.

[0061] The method comprises the following steps:

[0062] Step S1, preparing a combined collector for reverse flotation of fine feldspar with a mass concentration of 10% to 20%;

[0063] Step S2: performing laser particle size analysis on the mineral powder. Based on the analysis results, using 400-500 mesh and 40-140 mesh sieves to remove large particles of impurities and fine particles of mud, respectively, to obtain pretreated quartz-containing mineral powder;

[0064] Step S3: pouring the pretreated quartz-containing ore powder into a flotation tank and adding deionized water to form a slurry; adding a pH adjuster to the slurry to adjust the pH value to 11-12, adding an inhibitor, the micro-feldspar reverse flotation combined collector prepared in step S1, and a frother under stirring conditions, and sequentially performing reverse flotation roughing, at least two reverse flotation cleanings, and at least two scavengings to obtain a quartz concentrate.

[0065] In step S3, the pH adjuster is sodium hydroxide; the inhibitor is sodium hexametaphosphate; and the foaming agent is No. 2 oil;

[0066] For each ton of mineral powder, the amount of sodium hexametaphosphate added is 100g to 200g; the amount of the combined collector added is 150g to 300g; and the amount of No. 2 oil added is 20g to 40g.

[0067] The mass concentration of the ore pulp is 20% to 40%, the rotation speed of the ore pulp stirring is 1500 to 2000 rpm, and the reverse flotation roughing time is 5 to 7 minutes.

[0068] The time for each reverse flotation selection is 4 to 8 minutes, and the time for each sweep selection is 4 to 6 minutes.

[0069] Example 1

[0070] The main minerals in a quartz-bearing deposit in Shaanxi are quartz, plagioclase, potassium feldspar, and ankerite, with content of 79%, 7%, 4%, and 4%, respectively. Small amounts of pyrite, calcite, and siderite are also present. The quartz grain size is generally coarse, with a small amount of quartz metasomatized along the edges and in the center of the potassium feldspar, making it difficult to completely dissociate.

[0071] According to the above technical scheme, in this embodiment, modified sodium oleate is first prepared, then modified sodium dodecyl sulfonate is prepared, and finally the prepared modified sodium oleate and modified sodium dodecyl sulfonate are mixed to obtain a combined collector.

[0072] Wherein, the preparation of modified sodium oleate comprises the following steps:

[0073] Step 1: Dissolve the formulated amount of sodium oleate in an acetone solution in a 70°C cold water bath, and after the liquid phase is homogenized, introduce sulfur trioxide gas to obtain a mixed liquid A;

[0074] Step 2: adding a formula amount of sodium hydroxide to the mixed liquid A to obtain a mixed liquid B, and drying the mixed liquid B to obtain an intermediate product C;

[0075] Step 3: dissolving the intermediate product C in the formula amount in methanol to generate a mixed liquid D under the action of a catalyst, and drying the mixed liquid D to obtain modified sodium oleate;

[0076] The mass ratio of sodium oleate, sulfur trioxide and sodium hydroxide is 1:2:1, the mass ratio of sodium oleate, acetone and methanol is 1:20:20, and the catalyst is concentrated sulfuric acid.

[0077] Figure 3 This is the infrared spectrum of the modified sodium oleate prepared in this example. As can be seen from the figure, sulfonic acid groups and ether bonds are introduced into the modified sodium oleate. The main function of the sulfonic acid group is to form a cyclic chelate with metal ions to improve the capture ability of the modified sodium oleate. In addition to improving the dispersibility of the modified sodium oleate, the ether bond can also interact with aluminum ions on the surface of feldspar, adsorbing on its surface to enhance the capture ability.

[0078] Then, modified sodium dodecyl sulfate is prepared according to the following steps: chlorine gas is introduced into the sodium dodecyl sulfate at a temperature of 290° C. and a pressure of 6.5 MPa to replace hydrogen atoms with chlorine free radicals, thereby generating a chlorination reaction to produce sodium chlorododecyl sulfate; sodium hydroxide is added to an ethanol solution of the sodium chlorododecyl sulfate and the solution is heated to 170° C. to generate an elimination reaction to introduce a carbon-carbon double bond, thereby obtaining a mixed liquid E; and the mixed liquid E is reacted with water in the presence of a catalyst to obtain the modified sodium dodecyl sulfate.

[0079] The mass ratio of sodium dodecylsulfonate, chlorine, ethanol and sodium hydroxide is 1:1:10:1, and the catalyst is concentrated sulfuric acid;

[0080] Figure 4 This is the infrared spectrum of the modified sodium dodecyl sulfate prepared in this example. It can be seen from the figure that the modified sodium dodecyl sulfate introduces hydroxyl groups, and the introduced hydroxyl groups can significantly improve the hydrophilicity of the modified sodium dodecyl sulfate, which can significantly improve the dispersion of the modified sodium dodecyl sulfate in the slurry.

[0081] Then, 0.02 g of modified sodium oleate and 0.01 g of modified sodium dodecylsulfonate (ie, a mass ratio of 1:0.5) were mixed evenly to obtain a combined collector for use.

[0082] Use Figure 1 The method shown uses the combined collector prepared in this example to complete the reverse flotation of feldspar containing quartz ore powder. The specific reverse flotation operation steps are as follows:

[0083] First, the quartz ore powder was analyzed by laser particle size analysis. Figure 2 As shown, according to the results of laser particle size analysis, sieves with mesh sizes of 140 and 500 were selected to screen out large particles of impurities and fine particles of mud;

[0084] Then, 100g of the screened ore powder was poured into a flotation tank, deionized water was added to adjust the mass concentration to 20% of the ore pulp, and the pH value of the ore pulp of sodium hydroxide was added in sequence to be 12, the inhibitor sodium hexametaphosphate (consumption was 150g / t), and the feldspar reverse flotation combined collector prepared in step 1 was added. After adjusting the ore pulp at a stirring speed of 1900rmp for 3min, a frother No. 2 oil (consumption was 30g / t) was added. After fully adjusting the ore pulp for 3min, a scraper was started to carry out reverse flotation roughing, and the roughing time was 6min to obtain a concentrate. The concentrate obtained by the roughing was then subjected to two reverse flotation selections in sequence. The combined collector consumption was 100g / t during the selection. In this process, the ore pulp pH was controlled to be 12, and the selection time was 5min to obtain a reverse flotation quartz concentrate.

[0085] The roughing tailings were scavenged twice, the slurry pH value was controlled at 12, the combined collector dosage was 100 g / t, the scavenging time was 5 min, and reverse flotation tailings were obtained.

[0086] The quartz grade and quartz recovery rate finally obtained in this example are shown in Table 1.

[0087] Comparative Example 1

[0088] In this comparative example, 0.02 g of unmodified sodium oleate and 0.01 g of sodium dodecyl sulfate were uniformly mixed to obtain a combined collector; and then reverse flotation of feldspar containing quartz ore powder was completed according to the reverse flotation method provided in Example 1.

[0089] The quartz grade and quartz recovery rate finally obtained in this comparative example are shown in Table 1.

[0090] Example 2

[0091] The raw material components and preparation method of the combined collector used in this embodiment are the same as those in Example 1, except that, in this embodiment, the masses of modified sodium oleate and modified sodium dodecylsulfonate are both 0.015 g (i.e., a mass ratio of 1:1).

[0092] Then, reverse flotation of feldspar containing quartz ore powder was completed according to the reverse flotation method provided in Example 1, and the final quartz grade and quartz recovery rate were shown in Table 1.

[0093] Comparative Example 2

[0094] In this comparative example, 0.015 g of unmodified sodium oleate and 0.015 g of sodium dodecyl sulfate (ie, a mass ratio of 1:1) were uniformly mixed to obtain a combined collector.

[0095] Then, reverse flotation of feldspar containing quartz ore powder was completed according to the reverse flotation method provided in Example 1, and the final quartz grade and quartz recovery rate were shown in Table 1.

[0096] Example 3

[0097] The raw material components and preparation method of the combined collector used in this embodiment are the same as those in Example 1, except that 0.012 g of modified sodium oleate and 0.018 g of modified sodium dodecylsulfonate (i.e., a mass ratio of 1:1.5) are uniformly mixed to obtain the combined collector.

[0098] Then, reverse flotation of feldspar containing quartz ore powder was completed according to the reverse flotation method provided in Example 1, and the final quartz grade and quartz recovery rate were shown in Table 1.

[0099] Comparative Example 3

[0100] In this comparative example, 0.012 g of unmodified sodium oleate and 0.018 g of unmodified sodium dodecyl sulfate (ie, a mass ratio of 1:1.5) were uniformly mixed to obtain a combined collector.

[0101] Then, reverse flotation of feldspar containing quartz ore powder was completed according to the reverse flotation method provided in Example 1, and the final quartz grade and quartz recovery rate were shown in Table 1.

[0102] Comparative Example 5

[0103] In this comparative example, single modified sodium oleate was used as a collector, and the reverse flotation method disclosed in Example 1 was adopted to complete the reverse flotation of feldspar containing quartz ore powder. The final quartz grade and quartz recovery rate were shown in Table 1.

[0104] Comparative Example 6

[0105] In this comparative example, sodium oleate was used as a collector, and the method disclosed in Example 1 was used to complete the reverse flotation of feldspar containing quartz ore powder. The final quartz grade and quartz recovery rate were shown in Table 1.

[0106]

[0107]

[0108] Table 1. Reverse flotation results of quartz ore with different collectors

[0109] As can be seen from Table 1, the combined collector prepared by mixing modified sodium oleate and modified sodium dodecyl sulfate in a mass ratio of 1:1 provided by the present invention has the best effect on reverse flotation of quartz ore; when the mass ratio of modified sodium oleate to modified sodium dodecyl sulfate is 1:0.5, the flotation effect is second best; when single sodium oleate is used as a collector, the flotation effect is the worst.

[0110] By comparing Examples 1 to 3 with Comparative Examples 1 to 5, it can be seen that:

[0111] Compared to a combined collector made from an unmodified mixture of sodium oleate and sodium dodecyl sulfate, the combined collector made from a mixture of modified sodium oleate and modified sodium dodecyl sulfate has a better feldspar capture capability, resulting in higher-grade quartz. Furthermore, the combined collector made from a mixture of modified sodium oleate and modified sodium dodecyl sulfate also significantly improves the recovery rate of quartz.

[0112] The feldspar capture ability of the modified sodium oleate is worse than that of the unmodified sodium oleate, but not as good as the combined collector provided by the present invention.

[0113] In summary, the modified combined collector in Example 2 has the best effect and the highest recovery rate.

[0114] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0115] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0116] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A combined collector for reverse flotation of micro-feldspar, characterized in that: It includes modified sodium oleate and modified sodium dodecylsulfonate, and the structural formula of the modified sodium oleate is: The structural formula of the modified sodium lauryl sulfonate is: Where n+m=10.

2. The micro-feldspar reverse flotation combined collector according to claim 1, characterized in that: The mass ratio of the modified sodium oleate to the modified sodium dodecylsulfonate is 1:(0.5-1.5).

3. The combined collector for reverse flotation of micro-feldspar according to claim 1, characterized in that: The preparation of the modified sodium oleate comprises the following steps: Step 1: Dissolve the formulated amount of sodium oleate in an acetone solution in a cold water bath, and then introduce sulfur trioxide gas to obtain a mixed liquid A; Step 2: adding a formula amount of sodium hydroxide to the mixed liquid A to obtain a mixed liquid B, and drying the mixed liquid B to obtain an intermediate product C; Step 3: dissolving the intermediate product C in the formula amount in methanol to generate a mixed liquid D under the action of a catalyst, and drying the mixed liquid D; The temperature of the cold water bath is 50° C. to 80° C., the mass ratio of the sodium oleate, sulfur trioxide, and sodium hydroxide is 1:(2-3):1, the mass ratio of the sodium oleate, acetone, and methanol is 1:(15-20):(15-20), and the catalyst is concentrated sulfuric acid.

4. The combined collector for reverse flotation of micro-feldspar according to claim 1, wherein: The preparation of the modified sodium dodecyl sulfate comprises: introducing chlorine gas into sodium dodecyl sulfate at a temperature of 280° C. to 320° C. and a pressure of 5 to 7 MPa to generate sodium chlorododecyl sulfate; adding sodium hydroxide to an ethanol solution of the sodium chlorododecyl sulfate and heating the solution to 150° C. to 180° C. to induce an elimination reaction to introduce a carbon-carbon double bond, thereby obtaining a mixed liquid E; and allowing the mixed liquid E to undergo an addition reaction with water under the action of a catalyst to obtain the modified sodium dodecyl sulfate; The mass ratio of the sodium dodecylsulfonate, chlorine, ethanol and sodium hydroxide is 1:1:(8-10):1, and the catalyst is concentrated sulfuric acid.

5. A method for reverse flotation of feldspar containing quartz ore powder, characterized in that: The method adopts the micro-feldspar reverse flotation combined collector according to any one of claims 1 to 4.

6. The reverse flotation method for feldspar containing quartz ore powder according to claim 5, characterized in that: The quartz-containing mineral powder is the tailings of quartz vein-type gold mine.

7. The reverse flotation method for feldspar containing quartz ore powder according to claim 5, characterized in that: The method comprises the following steps: Step S1, preparing a combined collector for reverse flotation of fine feldspar with a mass concentration of 10% to 20%; Step S2, removing large impurities of 400-500 mesh and fine mud particles of 40-140 mesh from the quartz-containing ore powder to obtain pretreated quartz-containing ore powder; Step S3: pouring the pretreated quartz-containing ore powder into a flotation tank and adding deionized water to form a slurry; adding a pH adjuster to the slurry to adjust the pH value to 11-12, and then adding an inhibitor, the micro-feldspar reverse flotation combined collector prepared in step S1, and a frother under stirring conditions, and sequentially performing reverse flotation roughing, at least two reverse flotation cleanings, and at least two scavengings to obtain a quartz concentrate.

8. The reverse flotation method for feldspar containing quartz ore powder according to claim 7, characterized in that: In step S3, the pH adjuster is sodium hydroxide; the inhibitor is sodium hexametaphosphate; and the foaming agent is No. 2 oil; Among them, for each ton of mineral powder, the added amount of sodium hexametaphosphate is 100g to 200g; the added amount of micro-feldspar reverse flotation combined collector is 150g to 300g; and the added amount of No. 2 oil is 20g to 40g.

9. The reverse flotation method for feldspar containing quartz ore powder according to claim 7, characterized in that: The mass concentration of the ore pulp is 20% to 40%, the stirring speed of the stirring condition is 1500 to 2000 rpm, and the reverse flotation roughing time is 5 to 7 minutes.

10. The reverse flotation method for feldspar containing quartz ore powder according to claim 7, characterized in that: Each reverse flotation selection takes 4 to 8 minutes, and each sweep selection takes 4 to 6 minutes. In the step 3, the amount of the feldspar reverse flotation combined collector added is calculated based on the mass of the ore powder in the slurry, and the amount used per ton is 150 to 300 g.

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