Mineral type rare earth ore direct flotation composite collecting agent, preparation method and flotation method

Abstract

The invention discloses a mineral type rare earth ore direct flotation composite collecting agent, a preparation method and a flotation method. The mineral type rare earth ore direct flotation composite collecting agent comprises fatty acid, fatty alcohol and a sodium hydroxide solution. Wherein the mass ratio of the fatty acid to the fatty alcohol is 10: 1, the mass concentration of the sodium hydroxide solution is 10-20%, and the mass of the sodium hydroxide solution is equal to the total mass of the fatty acid and the fatty alcohol. According to the mineral type rare earth ore direct flotation composite collecting agent, the preparation method and the flotation method, the mineral type rare earth ore direct flotation composite collecting agent has the advantages of being simple in process, high in selectivity, high in collecting performance, good in dispersity, environmentally friendly and low in price, and is used for micro-fine particle mineral type rare earth ore separation; and high-grade and high-recovery-rate flotation indexes can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of mineral processing, and more specifically, to a composite collector for positive flotation of mineral-type rare earth ores, a preparation method and a flotation method. Background Art

[0002] Rare earth deposits in my country are divided into weathering rare earth ores and mineral rare earth ores. Mineral rare earth ores are mainly separated and extracted by gravity separation, magnetic separation and flotation. Froth flotation can handle fine particles of minerals, so this technology is widely used in mineral rare earth ores. The key to froth flotation is the selection of flotation collectors. Common collectors for rare earth ores include carboxylic acids, hydroxamic acids and phosphoric acid collectors. Fatty acid collectors were the first collectors used in rare earth flotation, but traditional fatty acid collectors have the disadvantages of poor adaptability, poor dispersibility and low selectivity. In mineral flotation, other agents are often used in combination with them to improve the flotation effect.

[0003] For example, the Chinese invention patent with the patent publication number CN112474064A discloses a preparation and use method of a composite collector for complex rare earth ore flotation. In the above invention patent, by using a combination of hydroxamic acid collectors, fatty acid collectors and phosphonic acid compounds, the problem of heating the slurry during traditional reagent flotation is avoided. The Chinese invention patent with the patent publication number CN117046614A discloses a rare earth ore positive flotation combined collector, a preparation method and a flotation method using the same. In the above invention patent, chlorinated fatty acids are used as raw materials and compounded with hydroxamic acid to form a rare earth ore positive flotation combined collector. The collector can be used for the sorting of mineral-type rare earth ores with high mud content and fine embedded particle size, and can significantly improve the flotation concentrate grade and recovery rate. A Chinese invention patent with patent publication number CN112246441A discloses a flotation composite collector and its preparation method and application. The above invention patent proposes using peroxide and hydroxylamine salt as raw materials to prepare a composite collector containing hydroxamic acid compounds and alcohol, thereby achieving a synergistic collection effect between various flotation reagents. The above composite combined collector has the disadvantages of complex process flow, long time consumption, and high reagent price. Summary of the invention

[0004] The purpose of the present invention is to provide a composite collector for positive flotation of mineral-type rare earth ores, a preparation method and a flotation method. The composite collector for positive flotation of mineral-type rare earth ores has the advantages of simple process, strong selectivity, high collecting performance, good dispersibility, environmental protection and low price. It is used for the separation of fine-grained mineral-type rare earth ores and can obtain flotation indicators of high grade and high recovery rate.

[0005] In order to achieve these purposes and other advantages according to the present invention, a composite collector for positive flotation of mineral-type rare earth ores is provided, comprising the following components:

[0006] Fatty acids, fatty alcohols, and sodium hydroxide solution;

[0007] The mass ratio of fatty acid to fatty alcohol is 10:1, the mass concentration of sodium hydroxide solution is 10-20%, and its mass is equal to the total mass of fatty acid and fatty alcohol.

[0008] Preferably, in the mineral-type rare earth ore positive flotation composite collector, the fatty acid is a C8-C18 fatty acid, and the fatty alcohol is a C10-C16 fatty alcohol.

[0009] The present invention also provides a method for preparing the composite collector for positive flotation of mineral-type rare earth ores, comprising the following steps:

[0010] S1, melting fatty acids and fatty alcohols;

[0011] S2, mixing the melted fatty acids and fatty alcohols in S1 at a mass ratio of 10:1, and continuously stirring and mixing to obtain a mixture;

[0012] S3, adding a sodium hydroxide solution having a mass concentration of 10-20% equal to the mass of the mixture in S2, stirring and saponifying, to obtain a preform;

[0013] S4, adding deionized water to the preform obtained in S3 to dilute the preform to a mass concentration of 2-10%, thereby obtaining the mineral-type rare earth ore positive flotation composite collector.

[0014] Preferably, in the method for preparing a composite collector for positive flotation of mineral-type rare earth ores, the fatty acid and fatty alcohol in S1 are melted at a temperature of 50-70°C.

[0015] Preferably, in the method for preparing a composite collector for positive flotation of mineral-type rare earth ores, when the melted fatty acid and fatty alcohol are mixed in S2, the continuous stirring time is 5-6 minutes.

[0016] Preferably, in the method for preparing a composite collector for positive flotation of mineral-type rare earth ores, the stirring and saponification time in S3 is 5-10 minutes.

[0017] The present invention also provides a rare earth flotation method, which uses the above-mentioned mineral-type rare earth ore positive flotation composite collector, comprising the following steps:

[0018] A. Crush the rare earth ore until the particle size of the ore particles is less than 0.074 mm, accounting for 65-85%;

[0019] B. performing a rough flotation on the rare earth ore powder crushed in step A to obtain a rougher concentrate and a rougher tailings;

[0020] In the rough flotation, the dosage of water glass is 400-800g / t, the dosage of composite collector for direct flotation is 600-1000g / t, the pH value of ore pulp is 4-5.5, and the mass concentration of ore pulp is 30-40%;

[0021] C. Sweep the roughing tailings obtained in step B twice to obtain flotation tailings;

[0022] During scavenging, the dosage of composite collector for positive flotation is 200-300g / t;

[0023] D. performing three fine flotation operations on the rougher concentrate obtained in step B to obtain a flotation concentrate, and using the flotation concentrate as a rare earth concentrate;

[0024] In fine flotation, the dosage of water glass is 100-200g / t, and the dosage of composite collector in positive flotation is 200-300g / t.

[0025] Preferably, in the rare earth flotation method, the scavenged concentrate obtained by the first scavenging in step C is returned to the feed for the next rough flotation; the scavenged concentrate obtained by the second scavenging in step C is returned to the feed for the first scavenging in the next step C.

[0026] Preferably, in the rare earth flotation method, the tailings obtained from the first fine flotation in step D are returned to the feed for the next rough flotation; the tailings obtained from the second fine flotation in step D are returned to the feed for the first fine flotation in the next step D; and the tailings obtained from the third fine flotation in step D are returned to the feed for the second fine flotation in the next step D.

[0027] Preferably, in the rare earth flotation method, the time of rough flotation in step B is 4-6 minutes and the temperature is 20-55°C; the time of scavenging in step C is 1-2 minutes; and the time of fine flotation in step D is 1-2 minutes and the temperature is 20-55°C.

[0028] The beneficial effects of the present invention are:

[0029] 1. The composite collector for positive flotation of mineral-type rare earth ores of the present invention is prepared by using fatty acids as raw materials and compounding a certain amount of fatty alcohol. Natural fatty acids are cheap and easy to purchase, so that the cost of the composite collector for positive flotation of mineral-type rare earth ores is significantly reduced compared with industrial collectors such as H205 and salicylic hydroxamic acid.

[0030] 2. Compared with a single flotation collector, the composite collector for positive flotation of mineral-type rare earth ores of the present invention has the characteristics of high selectivity, strong collecting ability, low toxicity, good foaming ability and easy degradation, and can be adapted to the flotation of rare earths at room temperature.

[0031] 3. The rare earth flotation method of the present invention adopts a mineral-type rare earth ore positive flotation composite collector, and through the rare earth flotation process of 1 coarse 3 fine 2 sweep, not only can high-grade and high-recovery rare earth concentrate indicators be obtained, but also the loss of rare earth minerals in tailings is reduced, thereby improving economic benefits.

[0032] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flow chart of the rare earth flotation method. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0035] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] An embodiment of the present invention provides a composite collector for positive flotation of a mineral-type rare earth ore, comprising the following components:

[0037] C8-C18 fatty acids, C10-C16 fatty alcohols and sodium hydroxide solution.

[0038] The mass ratio of fatty acid to fatty alcohol is 10:1, the mass concentration of sodium hydroxide solution is 10-20%, and its mass is equal to the total mass of fatty acid and fatty alcohol.

[0039] The embodiment of the present invention also provides a method for preparing the above-mentioned composite collector for positive flotation of mineral-type rare earth ores, comprising the following steps:

[0040] S1, melting fatty acids and fatty alcohols;

[0041] S2, mixing the melted fatty acids and fatty alcohols in S1 at a mass ratio of 10:1, and continuously stirring and mixing to obtain a mixture;

[0042] S3, adding a sodium hydroxide solution having a mass concentration of 10-20% equal to the mass of the mixture in S2, stirring and saponifying, to obtain a preform;

[0043] S4, adding deionized water to the preform obtained in S3 to dilute the preform to a mass concentration of 2-10%, thereby obtaining the mineral-type rare earth ore positive flotation composite collector.

[0044] Wherein, in the preparation method of the composite collector for positive flotation of mineral-type rare earth ores, the fatty acid and fatty alcohol in S1 are melted at a temperature of 50-70°C.

[0045] When the melted fatty acids and fatty alcohols in S2 are mixed, the continuous stirring time is 5-6 minutes.

[0046] The stirring and saponification time in S3 is 5-10 minutes.

[0047] like Figure 1 As shown, an embodiment of the present invention further provides a rare earth flotation method, which uses the above-mentioned mineral-type rare earth ore positive flotation composite collector, comprising the following steps:

[0048] A. Crush the rare earth ore until the particle size of the ore particles is less than 0.074 mm, accounting for 65-85%;

[0049] B. performing a rough flotation on the rare earth ore powder crushed in step A to obtain a rougher concentrate and a rougher tailings;

[0050] In the rough flotation, the dosage of water glass is 400-800g / t, the dosage of composite collector for direct flotation is 600-1000g / t, the pH value of ore pulp is 4-5.5, and the mass concentration of ore pulp is 30-40%;

[0051] C. Sweep the roughing tailings obtained in step B twice to obtain flotation tailings;

[0052] During scavenging, the dosage of composite collector for positive flotation is 200-300g / t;

[0053] D. performing three fine flotation operations on the rougher concentrate obtained in step B to obtain a flotation concentrate, and using the flotation concentrate as a rare earth concentrate;

[0054] In fine flotation, the dosage of water glass is 100-200g / t, and the dosage of composite collector in positive flotation is 200-300g / t.

[0055] In the rare earth flotation method, the scavenged concentrate obtained by the first scavenging in step C is returned to the feed for the next rough flotation; the scavenged concentrate obtained by the second scavenging in step C is returned to the feed for the first scavenging in the next step C.

[0056] In the rare earth flotation method, the tailings obtained from the first fine flotation in step D are returned to the feed for the next rough flotation; the tailings obtained from the second fine flotation in step D are returned to the feed for the first fine flotation in the next step D; and the tailings obtained from the third fine flotation in step D are returned to the feed for the second fine flotation in the next step D.

[0057] Wherein, in the rare earth flotation method described above, the time of rough flotation in step B is 4-6 minutes and the temperature is 20-55°C; the time of scavenging in step C is 1-2 minutes; the time of fine flotation in step D is 1-2 minutes and the temperature is 20-55°C.

[0058] In order to prove the beneficial effects of the composite collector for positive flotation of mineral-type rare earth ores and its preparation method and the rare earth flotation method using the same in the present application, the following examples are carried out for verification:

[0059] In the following examples, the fatty acids, fatty alcohols and sodium hydroxide are all commercially available analytically pure; flotation uses a commercially available mechanical stirring flotation machine; the flotation pH adjusters use commercially available NaOH and HCl analytically pure; the rare earth ore is fluorocarbon cerium with a REO grade of 1-3%.

[0060] <Example 1>

[0061] The ore raw material selected in this embodiment is a bastnaesite-type rare earth ore from a certain place in Sichuan. The rare earth ore mainly contains gangue minerals such as barite, fluorite and quartz. The main rare earth mineral is bastnaesite, and the REO grade is only 2.34%.

[0062] The fatty acid in the composite collector raw material used in this embodiment is lauric acid, which is a saturated fatty acid, also known as dodecanoic acid, with a chemical formula of C 12 H 24 O2; fatty alcohol is lauryl alcohol, also known as dodecanol, with a chemical formula of C 12 H 26 O. The mass ratio of lauric acid to lauryl alcohol is 10:1; the mass concentration of the sodium hydroxide solution is 20%, and the ratio of its mass to the total mass of lauric acid and lauryl alcohol is 1:1.

[0063] The preparation method of the above positive flotation composite collector:

[0064] S1, dissolving lauric acid and lauryl alcohol;

[0065] S2, mixing the lauric acid and lauryl alcohol obtained in S1 at a mass ratio of 10:1, and continuously stirring and mixing until uniformly mixed to obtain a mixture pharmaceutical solution;

[0066] S3, adding a sodium hydroxide solution with a mass concentration of 20% equal to the total mass of lauric acid and lauryl alcohol to the mixed agent solution in S2, stirring and saponifying for 7 minutes to obtain a preform;

[0067] S4, adding deionized water to dilute the preformed product in S3 to a reagent solution with a mass concentration of 2%, thereby obtaining the mineral-type rare earth ore positive flotation composite collector.

[0068] The rare earth flotation method using the composite collector comprises the following steps:

[0069] A. Crush the rare earth ore until the particle size of the ore particles is less than 0.074 mm, accounting for 70%;

[0070] B. performing a rough flotation on the rare earth ore powder crushed in step A to obtain a rougher concentrate and a rougher tailings;

[0071] In the rough flotation, the dosage of water glass is 400g / t, the dosage of composite collector for positive flotation is 500g / t, the pH value of ore pulp is 4.5, and the mass concentration of ore pulp is 40%;

[0072] C. Sweep the roughing tailings obtained in step B twice to obtain flotation tailings;

[0073] During scavenging, the dosage of positive flotation composite collector is 200g / t;

[0074] D. performing three fine flotation operations on the rougher concentrate obtained in step B to obtain a flotation concentrate, and using the flotation concentrate as a rare earth concentrate;

[0075] During fine flotation, the amount of water glass used is 100g / t, and the amount of composite collector used for positive flotation is 200g / t.

[0076] The scavenged concentrate obtained by the first scavenging in step C is returned to the feed for the next rough flotation; the scavenged concentrate obtained by the second scavenging in step C is returned to the feed for the first scavenging in step C for the next time.

[0077] Among them, the tailings obtained from the first fine flotation in step D are returned to the next rough flotation feed; the tailings obtained from the second fine flotation in step D are returned to the first fine flotation in the next step D; the tailings obtained from the third fine flotation in step D are returned to the second fine flotation in the next step D.

[0078] The time of rough flotation in step B is 4 minutes and the temperature is 25°C; the time of scavenging flotation in step C is 2 minutes; the time of fine flotation in step D is 2 minutes and the temperature is 25°C.

[0079] The separation indexes of the rare earth flotation method using the above composite collector are as follows:

[0080] Table 1 Sorting index of Example 1

[0081]

[0082] <Example 2>

[0083] The ore raw material selected in this embodiment is a bastnaesite-type rare earth ore from a certain place in Sichuan. The rare earth ore mainly contains gangue minerals such as barite, fluorite and quartz. The main rare earth mineral is bastnaesite, and the REO grade is only 2.34%.

[0084] The collector used in this example is different from that in Example 1 in that the single collector component with 0 amount of lauryl alcohol added is lauric acid and sodium hydroxide solution, wherein the mass concentration of the sodium hydroxide solution is 20%, and the mass ratio of the sodium hydroxide solution to the mass of lauric acid is 1:1.

[0085] The above single collector preparation method:

[0086] S1, melted lauric acid;

[0087] S2, adding a sodium hydroxide solution with a mass concentration of 20% equal to the mass of lauric acid to the lauric acid solution, stirring and saponifying for 7 minutes to obtain a preform;

[0088] S3, adding deionized water to dilute the preformed product in S2 to a pharmaceutical solution with a mass concentration of 2%, thereby obtaining the single collector.

[0089] The rare earth flotation method using the above single collector comprises the following steps:

[0090] A. Crush the rare earth ore until the particle size of the ore particles is less than 0.074 mm, accounting for 70%;

[0091] B. performing a rough flotation on the rare earth ore powder crushed in step A to obtain a rougher concentrate and a rougher tailings;

[0092] In the rough flotation, the dosage of water glass is 400g / t, the dosage of composite collector for positive flotation is 600g / t, the pH value of ore pulp is 4.5, and the mass concentration of ore pulp is 40%;

[0093] C. Sweep the roughing tailings obtained in step B twice to obtain flotation tailings;

[0094] During the sweeping process, the dosage of the composite collector for positive flotation is 300g / t;

[0095] D. performing three fine flotation operations on the rougher concentrate obtained in step B to obtain a flotation concentrate, and using the flotation concentrate as a rare earth concentrate;

[0096] During fine flotation, the amount of water glass used is 200g / t, and the amount of composite collector used for positive flotation is 300g / t.

[0097] The scavenged concentrate obtained by the first scavenging in step C is returned to the feed for the next rough flotation; the scavenged concentrate obtained by the second scavenging in step C is returned to the feed for the first scavenging in step C for the next time.

[0098] Among them, the tailings obtained from the first fine flotation in step D are returned to the next rough flotation feed; the tailings obtained from the second fine flotation in step D are returned to the first fine flotation in the next step D; the tailings obtained from the third fine flotation in step D are returned to the second fine flotation in the next step D.

[0099] The time of rough flotation in step B is 4 minutes and the temperature is 45°C; the time of scavenging flotation in step C is 2 minutes; the time of fine flotation in step D is 2 minutes and the temperature is 45°C.

[0100] The separation indexes of the rare earth flotation method using the above single collector are as follows:

[0101] Table 2 Sorting index of Example 2

[0102]

[0103] <Example 3>

[0104] The ore raw material selected in this embodiment is a bastnaesite-type rare earth ore from a certain place in Sichuan. The rare earth ore mainly contains gangue minerals such as barite, fluorite and quartz. The main rare earth mineral is bastnaesite, and the REO grade is only 2.34%.

[0105] The difference between the composite collector used in this embodiment and that in embodiment 1 is that the fatty acid in the raw material is palmitic acid, which is a saturated fatty acid, also known as palmitic acid, with a chemical formula of C 16 H 32 O2. The mass ratio of palmitic acid to lauryl alcohol is 10:1; the mass concentration of sodium hydroxide solution is 20%, and the ratio of its mass to the total mass of palmitic acid and lauryl alcohol is 1:1.

[0106] The preparation method of the above positive flotation composite collector:

[0107] S1, melt palmitic acid and lauryl alcohol;

[0108] S2, mixing the palmitic acid and lauryl alcohol obtained in S1 at a mass ratio of 10:1, and continuously stirring and mixing until uniformly mixed to obtain a mixture pharmaceutical solution;

[0109] S3, adding a sodium hydroxide solution with a mass concentration of 20% equal to the total mass of palmitic acid and lauryl alcohol to the mixed agent solution in S2, stirring and saponifying for 7 minutes to obtain a preform;

[0110] S4, adding deionized water to dilute the preformed product in S3 to a reagent solution with a mass concentration of 2%, thereby obtaining the mineral-type rare earth ore positive flotation composite collector.

[0111] The rare earth flotation method using the composite collector comprises the following steps:

[0112] A. Crush the rare earth ore until the particle size of the ore particles is less than 0.074 mm, accounting for 70%;

[0113] B. performing a rough flotation on the rare earth ore powder crushed in step A to obtain a rougher concentrate and a rougher tailings;

[0114] In the rough flotation, the dosage of water glass is 400g / t, the dosage of composite collector for positive flotation is 500g / t, the pH value of ore pulp is 4.5, and the mass concentration of ore pulp is 40%;

[0115] C. Sweep the roughing tailings obtained in step B twice to obtain flotation tailings;

[0116] During scavenging, the dosage of positive flotation composite collector is 200g / t;

[0117] D. performing three fine flotation operations on the rougher concentrate obtained in step B to obtain a flotation concentrate, and using the flotation concentrate as a rare earth concentrate;

[0118] During fine flotation, the amount of water glass used is 100g / t, and the amount of composite collector used for positive flotation is 200g / t.

[0119] The scavenged concentrate obtained by the first scavenging in step C is returned to the feed for the next rough flotation; the scavenged concentrate obtained by the second scavenging in step C is returned to the feed for the first scavenging in step C for the next time.

[0120] Among them, the tailings obtained from the first fine flotation in step D are returned to the next rough flotation feed; the tailings obtained from the second fine flotation in step D are returned to the first fine flotation in the next step D; the tailings obtained from the third fine flotation in step D are returned to the second fine flotation in the next step D.

[0121] The time of rough flotation in step B is 4 minutes and the temperature is 25°C; the time of scavenging flotation in step C is 2 minutes; the time of fine flotation in step D is 2 minutes and the temperature is 25°C.

[0122] The separation indexes of the rare earth flotation method using the above composite collector are as follows:

[0123] Table 3 Sorting index of Example 3

[0124]

[0125] Comparison between Example 1 and Example 2 shows that the flotation performance of the composite collector of lauric acid and lauryl alcohol described in the present invention is significantly stronger than that of the single lauric acid collector, and the REO grade and recovery rate of the obtained rare earth ore flotation product are 5.7 percentage points and 10.37 percentage points higher, respectively. Comparison between Example 1 and Example 3 shows that the performance of the composite collector prepared by different types of fatty acids and fatty alcohols is slightly different.

[0126] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A composite collector for positive flotation of mineral-type rare earth ores, characterized in that: Includes the following components: Fatty acids, fatty alcohols, and sodium hydroxide solution; The mass ratio of fatty acid to fatty alcohol is 10:1, the mass concentration of sodium hydroxide solution is 10-20%, and its mass is equal to the total mass of fatty acid and fatty alcohol.

2. A composite collector for positive flotation of mineral-type rare earth ores as claimed in claim 1, characterized in that: The fatty acid is a C8-C18 fatty acid, and the fatty alcohol is a C10-C16 fatty alcohol.

3. A method for preparing a composite collector for positive flotation of mineral-type rare earth ores as claimed in claim 1 or 2, characterized in that: The following steps are involved: S1, melting fatty acids and fatty alcohols; S2, mixing the melted fatty acids and fatty alcohols in S1 at a mass ratio of 10:1, and continuously stirring and mixing to obtain a mixture; S3, adding a sodium hydroxide solution having a mass concentration of 10-20% equal to the mass of the mixture in S2, stirring and saponifying, to obtain a preform; S4, adding deionized water to the preform obtained in S3 to dilute the preform to a mass concentration of 2-10%, thereby obtaining the mineral-type rare earth ore positive flotation composite collector.

4. The method for preparing a composite collector for positive flotation of mineral-type rare earth ores according to claim 3, characterized in that: The fatty acids and fatty alcohols in S1 are melted at a temperature of 50-70°C.

5. The method for preparing a composite collector for positive flotation of mineral-type rare earth ores according to claim 3, characterized in that: When the melted fatty acids and fatty alcohols in S2 are mixed, the continuous stirring time is 5-6 minutes.

6. The method for preparing a composite collector for positive flotation of mineral-type rare earth ores according to claim 3, characterized in that: The stirring saponification time in S3 is 5-10 minutes.

7. A rare earth flotation method, using the composite collector for positive flotation of mineral-type rare earth ores as claimed in claim 1 or 2, characterized in that: The following steps are involved: A. Crush the rare earth ore until the particle size of the ore particles is less than 0.074 mm, accounting for 65-85%; B. performing a rough flotation on the rare earth ore powder crushed in step A to obtain a rougher concentrate and a rougher tailings; In the rough flotation, the dosage of water glass is 400-800g / t, the dosage of composite collector for direct flotation is 600-1000g / t, the pH value of ore pulp is 4-5.5, and the mass concentration of ore pulp is 30-40%; C. Sweep the roughing tailings obtained in step B twice to obtain flotation tailings; During scavenging, the dosage of composite collector for positive flotation is 200-300g / t; D. performing three fine flotation operations on the rougher concentrate obtained in step B to obtain a flotation concentrate, and using the flotation concentrate as a rare earth concentrate; In fine flotation, the dosage of water glass is 100-200g / t, and the dosage of composite collector in positive flotation is 200-300g / t.

8. A rare earth flotation method as claimed in claim 7, characterized in that: The scavenged concentrate obtained by the first scavenging in step C is returned to the feed for the next rough flotation; the scavenged concentrate obtained by the second scavenging in step C is returned to the feed for the first scavenging in step C for the next time.

9. A rare earth flotation method as claimed in claim 7, characterized in that: The tailings obtained from the first fine flotation in step D are returned to the next rough flotation feed; the tailings obtained from the second fine flotation in step D are returned to the first fine flotation in the next step D; the tailings obtained from the third fine flotation in step D are returned to the second fine flotation in the next step D.

10. A rare earth flotation method as claimed in claim 7, characterized in that: The time of rough flotation in step B is 4-6 minutes, and the temperature is 20-55°C; the time of scavenging flotation in step C is 1-2 minutes; the time of fine flotation in step D is 1-2 minutes, and the temperature is 20-55°C.

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