Preparation process of composite collecting agent for low-temperature spodumene flotation

Abstract

The invention relates to the technical field of mineral processing, and discloses a preparation process of a composite collecting agent for low-temperature spodumene flotation, and the composite collecting agent comprises the following components by weight: 20-30% of oxidized paraffin soap; 3%-8% of dialkyl phosphinic acid; 8%-12% of fatty acid methyl ester ethoxylate; 5%-10% of kerosene; 15%-20% of propylene glycol; 1% to 3% of 1-butyl-3-methylimidazolium hexafluorophosphate; 0.1% to 0.5% of potassium sorbate; 3%-5% of methyl isobutyl carbinol; the preparation method comprises the following steps: carrying out dehydration and pre-activation pretreatment on the oxidized paraffin soap, the dialkyl phosphinic acid and the triethanolamine, carrying out a three-stage mixing process of a mixing stage A, a mixing stage B and a mixing stage C on the oxidized paraffin soap, the dialkyl phosphinic acid and the triethanolamine, and finally carrying out nitrogen protection packaging to obtain a finished product when the pH value, the viscosity, the low-temperature stability and the effective activity content are detected to be qualified. The composite collecting agent is specially used for flotation of spodumene at the low temperature of 5-15 DEG C, can efficiently and selectively collect spodumene minerals, and has the advantages of being good in dissolution dispersity at the low temperature, high in adsorption selectivity, capable of saving energy, efficient and high in universality.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically to a process for preparing a composite collector for low-temperature spodumene flotation. Background Technology

[0002] Spodumene, as one of the main minerals for lithium extraction, requires efficient separation, which is a crucial link in the lithium battery industry chain. Flotation is the core method for enriching spodumene, with anionic collectors (such as oxidized paraffin soap) being widely used. However, in high-altitude, high-latitude, or low-temperature winter environments, conventional collectors, represented by oxidized paraffin soap (mainly sodium fatty acid salts), exhibit significant drawbacks in low-temperature slurries: the solubility and dispersibility of sodium soap decrease sharply, leading to easy crystallization and precipitation, resulting in loss of effective components and reduced collecting activity; simultaneously, molecular diffusion slows down at low temperatures, adsorption kinetics deteriorate, and the selective collection ability for spodumene decreases. To address this issue, existing technologies often rely on external heating of the slurry or the use of large amounts of solvents, which not only results in high energy consumption and significantly increased costs but also potentially introduces environmental and safety issues. Some studies have attempted to combine multiple reagents to improve low-temperature performance, but these often neglect the low-temperature compatibility and synergistic mechanisms between components, leading to complex formulations, unstable effects, and difficulty in achieving a balance between high selectivity, high recovery rate, and broad ore adaptability. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a composite collector preparation process for low-temperature spodumene flotation, which has the advantages of good solubility and dispersibility at low temperatures, high adsorption selectivity, energy efficiency, and broad applicability. It solves the problems of low activity, poor selectivity, reliance on external heating, and high energy consumption of traditional collectors in low-temperature environments.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a process for preparing a composite collector for low-temperature spodumene flotation, comprising the following steps: Step 1: Preparation of reagent components: Prepare the following ingredients in the specified weight ratio: oxidized paraffin soap, dialkylphosphinoic acid, fatty acid methyl ester ethoxylate, kerosene, propylene glycol, 1-butyl-3-methylimidazolium hexafluorophosphate, potassium sorbate, methyl isobutyl methanol and triethanolamine. Step 2, Pretreatment: The prepared oxidized paraffin soap, dialkylphosphine acid and triethanolamine are subjected to dehydration and pre-activation pretreatment respectively; Step 3, Mixing Stage A: Add the pretreated oxidized paraffin soap, dialkylphosphine acid and triethanolamine to the reaction vessel, mix them initially and allow the saponification reaction to occur; Step 4, Mixing Stage B: Add fatty acid methyl ester ethoxylate, kerosene, propylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate sequentially to the product of Stage A for emulsification and dispersion; Step 5, Mixing Stage C: Cool the system to 25-30℃, add methyl isobutyl methanol and potassium sorbate, and perform final conditioning and homogenization; Step Six: Quality Inspection and Packaging: After testing for pH value, viscosity, low-temperature stability and effective activity content, qualified products are sealed under nitrogen protection to obtain the finished composite collector.

[0005] Preferably, the components and their weight ratios of the composite collector in step one are as follows: 20%-30% oxidized paraffin soap; 3%-8% dialkylphosphinoic acid; 8%-12% fatty acid methyl ester ethoxylate; 5%-10% kerosene; 15%-20% propylene glycol; 1%-3% 1-butyl-3-methylimidazolium hexafluorophosphate; 0.1%-0.5% potassium sorbate; 3%-5% methyl isobutyl methanol; and 10%-15% triethanolamine.

[0006] Preferably, the oxidized paraffin soap is prepared by oxidizing paraffin in air and then reacting it with sodium hydroxide via a saponification reaction, and its chemical formula is: (1) Oxidation reaction: In the formula, It is a mixture of alkanes in raw paraffin. It is oxygen in the air. Fatty acids produced by oxidation; (2) Saponification reaction: In the formula, Fatty acids are oxidation products. As a saponification reagent, To produce the final product, oxidized paraffin soap, It is water used in the saponification reaction.

[0007] Preferably, the pretreatment conditions for step two are as follows: the oxidized paraffin soap is dried at 55-60℃ and under a vacuum of -0.09 to -0.08 MPa for 2-3 hours to reduce its moisture content to ≤0.5%.

[0008] Preferably, the pretreatment conditions for step two are as follows: Dialkylphosphine acid is dissolved in anhydrous ethanol with a concentration ≥99% in a water bath at 70-75°C, then purified by static crystallization at 0-4°C for 6-8 hours. After vacuum filtration and washing the crystals 2-3 times with anhydrous ethanol of the same concentration pre-cooled to 0-4°C, the crystals are dried at 55-60°C and a vacuum degree of -0.09~-0.08MPa for 2-3 hours to obtain white dialkylphosphine acid crystalline solid with a purity ≥98%.

[0009] Preferably, the pretreatment conditions for step two are as follows: triethanolamine is dynamically dehydrated using a type 4A molecular sieve for 36-48 hours to reduce its moisture content to ≤0.2%.

[0010] Preferably, the mixing conditions for step three, stage A are as follows: The reaction is carried out at 45-50℃ and 200-300 rpm for 40-50 minutes, during which the system changes from turbid to a homogeneous, light yellow, transparent liquid. The chemical formula of the saponification reaction occurring during this process is: In the formula, This indicates the long-chain fatty acid components contained in the oxidized paraffin mixture, among which... The number of carbon atoms is mainly alkyl chain, It refers to triethanolamine. This indicates the triethanolamine fatty acid salt produced in the reaction. It is generated as a trace byproduct.

[0011] Preferably, the mixing conditions for step four stage B are as follows: maintain the temperature at 40-45℃, gradually increase the rotation speed to 800-1000 rpm in a phased gradient speed-up mode, and shear emulsify for 50-60 minutes to form a stable oil-in-water emulsion.

[0012] Preferably, the mixing conditions for step five, stage C are: mixing at 22-25℃ and 300-400 rpm for 20-25 minutes to obtain a uniformly fluid amber-colored translucent liquid.

[0013] Preferably, the composite collector is used in low-temperature spodumene flotation to selectively collect spodumene minerals in a low-temperature slurry environment of 5-15℃.

[0014] Compared with the prior art, the present invention provides a process for preparing a composite collector for low-temperature spodumene flotation, which has the following beneficial effects: 1. This invention introduces triethanolamine to replace traditional sodium hydroxide in the saponification reaction to generate organic ammonium soap, which can effectively improve low-temperature fluidity and dispersibility. Compared with the problem of easy crystallization and precipitation of sodium soap, organic ammonium soap maintains a uniform and transparent liquid state in a wide temperature range of -10~15℃, which enables the composite collector to be quickly dispersed in the slurry and avoids the loss of effective components due to low-temperature solidification.

[0015] 2. This invention achieves the beneficial effect of enhancing the low-temperature interface adsorption efficiency by constructing a synergistic antifreeze system of propylene glycol and ionic liquid. In this system, propylene glycol acts as an antifreeze agent to lower the freezing point of the system, while 1-butyl-3-methylimidazolium hexafluorophosphate improves the oil-water interfacial tension through electrostatic interaction. The synergistic effect of the two allows the agent to maintain a stable nanoemulsion structure below 5°C.

[0016] 3. This invention, by combining dialkylphosphonic acid and fatty acid methyl ester ethoxylate, can precisely control the selective collection of minerals. Specifically, dialkylphosphonic acid specifically chelates metal ions on the surface of spodumene, while fatty acid methyl ester ethoxylate simultaneously inhibits silicate gangue, forming a selective adsorption-efficient separation mechanism. This is a significant improvement over single sodium soap collectors, giving it a universal advantage in the processing of complex ores. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 A process for preparing a composite collector for low-temperature spodumene flotation includes the following steps: Step 1: Preparation of reagent components: Prepare the following ingredients in the specified weight ratio: oxidized paraffin soap, dialkylphosphinoic acid, fatty acid methyl ester ethoxylate, kerosene, propylene glycol, 1-butyl-3-methylimidazolium hexafluorophosphate, potassium sorbate, methyl isobutyl methanol and triethanolamine. Step 2, Pretreatment: The prepared oxidized paraffin soap, dialkylphosphine acid and triethanolamine are subjected to dehydration and pre-activation pretreatment respectively; Step 3, Mixing Stage A (Initial Mixing): The pretreated oxidized paraffin soap, dialkylphosphine acid and triethanolamine are added to the reaction vessel for initial mixing and saponification reaction. Step 4, Mixing Stage B: Add fatty acid methyl ester ethoxylate, kerosene, propylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate sequentially to the product of Stage A for emulsification and dispersion; Step 5, Mixing Stage C (Final Mixing): Cool the system to 25-30℃, add methyl isobutyl methanol and potassium sorbate, and perform final conditioning and homogenization; Step Six: Quality Inspection and Packaging: After testing for pH value, viscosity, low-temperature stability and effective activity content, qualified products are sealed under nitrogen protection to obtain the finished composite collector.

[0020] Specifically, the components and their weight ratios of the compound collector in step one are as follows: 20%-30% oxidized paraffin soap; 3%-8% dialkylphosphinoic acid; 8%-12% fatty acid methyl ester ethoxylate; 5%-10% kerosene; 15%-20% propylene glycol; 1%-3% 1-butyl-3-methylimidazolium hexafluorophosphate; 0.1%-0.5% potassium sorbate; 3%-5% methyl isobutyl methanol (MIBC); and 10%-15% triethanolamine.

[0021] The specific functions of the ingredients are shown in Table 1 below: Table 1 Specifically, oxidized paraffin soap is usually prepared by oxidizing paraffin in air and then reacting it with sodium hydroxide via a saponification reaction. Its chemical formula is: (1) Oxidation reaction: In the formula, It is a mixture of alkanes in raw paraffin. It is oxygen in the air. Fatty acids produced by oxidation; (2) Saponification reaction: In the formula, Fatty acids are oxidation products. As a saponification reagent, To produce the final product, oxidized paraffin soap, It is water used in the saponification reaction.

[0022] Specifically, the pretreatment conditions for step two are as follows: the oxidized paraffin soap is dried at 55-60℃ and under a vacuum of -0.09~-0.08MPa for 2-3 hours to reduce its moisture content to ≤0.5%.

[0023] The above-mentioned low-temperature vacuum drying process can effectively remove free water and low-boiling-point volatiles from oxidized paraffin soap, avoiding soap hydrolysis, stratification and mold growth caused by moisture during subsequent compounding, and ultimately ensuring the chemical stability and phase uniformity of the compound collector during low-temperature storage and use.

[0024] Specifically, the pretreatment conditions for step two are as follows: Dialkylphosphonic acid is dissolved in anhydrous ethanol with a concentration of ≥99% in a water bath at 70-75℃, and then purified by static crystallization at 0-4℃ for 6-8 hours. After vacuum filtration and washing the crystals 2-3 times with anhydrous ethanol of the same concentration pre-cooled to 0-4℃, the crystals are dried at 55-60℃ and a vacuum degree of -0.09~-0.08MPa for 2-3 hours to obtain white dialkylphosphonic acid crystalline solid with a purity of ≥98%.

[0025] The purity of dialkylphosphonic acid was significantly improved by the above-mentioned recrystallization and vacuum drying purification processes, and residual organophosphonates and neutral oil impurities from the synthesis process were removed, thereby enhancing its adhesion to the spodumene surface at low temperatures. It has selective chelating ability at the site, while avoiding hydrolysis side reactions between trace amounts of water in dialkylphosphinoic acid and ionic liquid components.

[0026] Specifically, the pretreatment conditions for step two are as follows: triethanolamine is dynamically dehydrated using a type 4A molecular sieve (pore size 0.4nm) for 36-48 hours until its moisture content is ≤0.2%.

[0027] Through the above-mentioned dynamic dehydration treatment using molecular sieves, trace amounts of water in triethanolamine are deeply removed, preventing side reactions with ionic liquid components and dialkylphosphine, ensuring the chemical stability and long-term storage performance of the composite collector system, and improving its reactivity with organic bases under low-temperature conditions.

[0028] Specifically, in step three, stage A, the mixing conditions are as follows: The reaction is carried out at 45-50℃ and 200-300 rpm for 40-50 minutes. During stage A, a saponification reaction occurs, and the system changes from turbid to a homogeneous, light yellow, transparent liquid. The core saponification reaction occurring in this process can be represented by the following chemical formula: In the formula, This indicates the long-chain fatty acid components contained in the oxidized paraffin mixture, among which... The number of carbon atoms is mainly Alkyl chains (containing small amounts of other functional groups). This refers to triethanolamine, which acts as an organic base in this reaction, providing the necessary alkaline environment for neutralization and participating directly in the reaction. This indicates the triethanolamine fatty acid salt (an organic ammonium soap) produced in the reaction, which is one of the key active ingredients that allows the mixture to maintain good solubility and dispersibility at low temperatures. It is generated as a trace byproduct; The advantage is that the above steps are a neutralization reaction between organic acids (fatty acids) and organic bases (triethanolamine). Compared to using sodium hydroxide to produce traditional sodium soap... The resulting triethanolamine soap exhibits better water solubility, low-temperature fluidity, and compatibility with other organic components. This is one of the key process steps designed for this composite collector to adapt to the low-temperature flotation environment. The transformation of the system from turbid to a homogeneous and transparent liquid is a sign that the water-insoluble free fatty acids have been converted into soluble triethanolamine soap.

[0029] Through the above-mentioned organic saponification reaction, the insoluble free fatty acids are converted into triethanolamine fatty acid salts, thereby improving the low-temperature solubility (it can still remain clear and transparent at 5°C), dispersibility and compatibility with other organic components of the collector component. At the same time, the introduction of triethanolamine optimizes the pH buffering capacity of the system, thereby avoiding the problem of excessively high ionic strength of the pulp caused by inorganic alkali.

[0030] Specifically, in step four, stage B, the mixing conditions are as follows: maintain the temperature at 40-45℃, gradually increase the rotation speed to 800-1000 rpm using a phased gradient speed-up mode, and shear emulsify for 50-60 minutes to form a stable oil-in-water emulsion.

[0031] The gradient-increase shear emulsification process described above achieves micro-nano-scale dispersion of the oil phase (kerosene, dialkylphosphonic acid) in the aqueous matrix, forming a stable O / W emulsion. This improves the mass transfer efficiency, uniformity of action, and low-temperature stability of the agent (no stratification after 48 hours at 5°C), while avoiding local overheating and component degradation caused by high-speed shearing.

[0032] Specifically, in step five, stage C, the mixing conditions are as follows: mix for 20-25 minutes at 22-25℃ and 300-400 rpm, avoiding excessive foaming, to obtain a uniformly fluid amber-colored, translucent liquid.

[0033] Through the above-mentioned low-temperature and low-speed conditioning and homogenization, the components can achieve molecular-level synergistic equilibrium under mild conditions, giving full play to the low-temperature synergistic effect of ionic liquid and organophosphonic acid, while avoiding component degradation and excessive foaming caused by high temperature, and finally obtaining a finished product with excellent flowability and good storage stability.

[0034] Specifically, the composite collector is used in low-temperature spodumene flotation to efficiently and selectively collect spodumene minerals in a low-temperature slurry environment of 5-15℃.

[0035] The composite collector prepared above was used in the following four scenarios and compared with existing conventional collectors or collectors without key components, specifically: Example 1 Using the above preparation process, a composite collector was prepared according to the following mass percentages: 25% oxidized paraffin soap, 6% dialkylphosphinoic acid, 10% fatty acid methyl ester ethoxylate, 7% kerosene, 18% propylene glycol, 2% 1-butyl-3-methylimidazolium hexafluorophosphate, 0.3% potassium sorbate, 4% MIBC, and the balance being triethanolamine. Take a sample of a certain spodumene ore ( (Grade 1.2%), after grinding, the pulp concentration was adjusted to 30%, the pulp temperature was controlled at 10℃, the pH was adjusted to 9.0 with sodium carbonate, sodium silicate (1.5kg / t) was added to suppress gangue, and then compound collector X (total dosage 0.8kg / t) was added to carry out a closed-circuit flotation test with one rougher, one cleaner and two scavengers.

[0036] Comparative Example 1 A comparative collector was prepared by replacing 1-butyl-3-methylimidazolium hexafluorophosphate and propylene glycol in composite collector X with water by equal mass, while keeping other components and preparation process unchanged. Parallel flotation tests were conducted under the exact same ore, slurry, and total reagent dosage as in Example 1.

[0037] Example 2 Using the above preparation process, a composite collector Y was prepared according to the following mass percentages: 28% oxidized paraffin soap, 5% dialkylphosphinoic acid, 9% fatty acid methyl ester ethoxylate, 8% kerosene, 16% propylene glycol, 1.5% 1-butyl-3-methylimidazolium hexafluorophosphate, 0.2% potassium sorbate, 3.5% MIBC, and the balance being triethanolamine. A sample of a lepidolite and spodumene coexisting mineral was taken ( (Grade 0.9%), after grinding, the pulp concentration was adjusted to 28%, the pulp temperature was controlled at 5℃, the pH was adjusted to 8.5 with sodium hydroxide, dextrin (0.5kg / t) was added to inhibit silicate gangue, and then composite collector Y (total dosage 1.0kg / t) was added to carry out a closed-circuit flotation test with one roughing, two cleaning and three scavenging.

[0038] Comparative Example 2 A conventional single anionic collector, oxidized paraffin soap (industrial grade, not compounded using this process), was used as a control collector. Under the same ore and slurry conditions as in Example 2, the dosage was adjusted to the same active ingredient content (approximately 1.1 kg / t), and parallel flotation tests were conducted.

[0039] Example 3 The same composite collector X as in Example 1 was used. A spodumene ore sample from the same source as in Example 1, but with a lower grade, was taken. (Grade 0.7%), after grinding, the pulp concentration was adjusted to 32%, the pulp temperature was controlled at 15℃, the pH was adjusted to 9.2 with sodium carbonate, sodium silicate (2.0 kg / t) and carboxymethyl cellulose (0.2 kg / t) were added to suppress gangue, and then a composite collector was added. (Total dosage 1.2 kg / t) A closed-circuit flotation test was conducted using one roughing, two cleaning, and three scavenging processes.

[0040] Comparative Example 3 Composite collector The triethanolamine in the sample is replaced by sodium hydroxide solution (to pre-convert the oxidized paraffin soap into pure sodium soap), while other components and preparation processes remain unchanged, to prepare a comparative collector. Parallel flotation tests were conducted under the exact same ore, slurry, and total reagent dosage conditions as in Example 3.

[0041] Example 4 Using the above preparation process, a composite collector was prepared according to the following mass percentages: 22% oxidized paraffin soap, 7.5% dialkylphosphinoic acid, 11% fatty acid methyl ester ethoxylate, 6% kerosene, 19% propylene glycol, 2.5% 1-butyl-3-methylimidazolium hexafluorophosphate, 0.4% potassium sorbate, 4.5% MIBC, and the balance being triethanolamine. A sample of spodumene ore with high calcium and magnesium impurities was taken. Grade 1.1%, (Content > 5%), after grinding, adjust the slurry to a concentration of 30%, control the slurry temperature at 8℃, adjust the pH to 9.5 with sodium carbonate, add sodium hexametaphosphate (0.8 kg / t) to disperse the slurry and inhibit calcium-magnesium gangue, and then add a composite collector. (Total dosage 1.0 kg / t) A closed-circuit flotation test with one roughing and one cleaning step was conducted.

[0042] Comparative Example 4 Composite collector The dialkylphosphinolic acid in the sample was replaced with an equal amount of oxidized paraffin soap, while other components and preparation processes remained unchanged, to prepare a comparative collector. Parallel flotation tests were conducted under the exact same ore, slurry, and total reagent dosage conditions as in Example 4. The key indicators of the closed-circuit flotation tests obtained in the examples and comparative examples are compared in Table 2 below. Table 2 Note: Flotation efficiency index = (concentrate grade / raw ore grade) × recovery rate, used to comprehensively evaluate the selectivity and recovery effect of collectors.

[0043] From Table 2, we can obtain: (1) Under the same low-temperature slurry environment, the spodumene recovery rate of Example 1 was 9.4 percentage points higher than that of Comparative Example 1, and the concentrate recovery rate was higher. The grade increased by 0.9 percentage points and the flotation efficiency index increased by 22.4%, indicating that the composite collector of the present invention enhances low-temperature dispersibility and selectivity through the synergistic effect of ionic liquid and organic soap. (2) Under extremely low temperature conditions of 5℃, the recovery rate of Example 2 was 16.6 percentage points higher than that of Comparative Example 2, and the amount of reagent used was reduced by 24%, and the concentrate grade was increased by 0.8 percentage points. This proves that the present invention completely solves the industry problem of conventional sodium soap solidification failure at low temperature through the antifreeze synergistic design of triethanolamine soap and propylene glycol, and achieves low-temperature high-efficiency flotation. (3) For low-grade spodumene, Example 3 still maintains a high recovery rate of 78.5% and a concentrate grade of 5.1% under the condition of 0.7%, which is 7.3 and 0.7 percentage points higher than Comparative Example 3, respectively. This proves that triethanolamine organic soap has better solubility and selectivity at low temperature than inorganic sodium soap, and can effectively reduce gangue entrainment. (4) Under conditions of high calcium and magnesium impurities, the recovery rate and concentrate grade of Example 4 were both better than those of Comparative Example 4, while the tailings grade decreased by 0.10 percentage points, indicating that dialkylphosphine has a positive effect on the recovery rate and concentrate grade of Example 4. The selective chelation effect is the key mechanism by which this invention improves the separation efficiency of spodumene and calcium-magnesium gangue.

[0044] In summary, this invention successfully prepared a composite collector with excellent flowability, high collecting activity, and selectivity at low temperatures of 5-15℃ through organic alkali saponification modification of oxidized paraffin soap, chelation enhancement with dialkylphosphine acid, low-temperature dispersion promotion with ionic liquid, and the construction of an O / W microemulsion system. Compared with conventional collectors, it improves spodumene recovery rate by 9-17 percentage points, reduces reagent dosage by 20-30%, and improves low-temperature storage stability and resistance to gangue interference. This provides a reliable technical solution for the efficient development of spodumene resources in cold regions and has good prospects for industrial application.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a composite collector for low-temperature spodumene flotation, characterized in that, Includes the following steps: Step 1: Preparation of reagent components: Prepare the following ingredients in the specified weight ratio: oxidized paraffin soap, dialkylphosphinoic acid, fatty acid methyl ester ethoxylate, kerosene, propylene glycol, 1-butyl-3-methylimidazolium hexafluorophosphate, potassium sorbate, methyl isobutyl methanol and triethanolamine. Step 2, Pretreatment: The prepared oxidized paraffin soap, dialkylphosphine acid and triethanolamine are subjected to dehydration and pre-activation pretreatment respectively; Step 3, Mixing Stage A: Add the pretreated oxidized paraffin soap, dialkylphosphine acid and triethanolamine to the reaction vessel, mix them initially and allow the saponification reaction to occur; Step 4, Mixing Stage B: Add fatty acid methyl ester ethoxylate, kerosene, propylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate sequentially to the product of Stage A for emulsification and dispersion; Step 5, Mixing Stage C: Cool the system to 25-30℃, add methyl isobutyl methanol and potassium sorbate, and perform final conditioning and homogenization; Step Six: Quality Inspection and Packaging: After testing for pH value, viscosity, low-temperature stability and effective activity content, qualified products are sealed under nitrogen protection to obtain the finished composite collector.

2. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The components and their weight ratios of the composite collector in step one are as follows: 20%-30% oxidized paraffin soap; 3%-8% dialkylphosphinoic acid; 8%-12% fatty acid methyl ester ethoxylate; 5%-10% kerosene; 15%-20% propylene glycol; 1%-3% 1-butyl-3-methylimidazolium hexafluorophosphate; 0.1%-0.5% potassium sorbate; 3%-5% methyl isobutyl methanol; and 10%-15% triethanolamine.

3. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The oxidized paraffin soap is prepared by oxidizing paraffin in air and then reacting it with sodium hydroxide via a saponification reaction. Its chemical formula is: (1) Oxidation reaction: In the formula, It is a mixture of alkanes in raw paraffin. It is oxygen in the air. Fatty acids produced by oxidation; (2) Saponification reaction: In the formula, Fatty acids are oxidation products. As a saponification reagent, To produce the final product, oxidized paraffin soap, It is water used in the saponification reaction.

4. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The pretreatment conditions for step two are as follows: the oxidized paraffin soap is dried at 55-60℃ and under a vacuum of -0.09 to -0.08 MPa for 2-3 hours to reduce its moisture content to ≤0.5%.

5. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The pretreatment conditions for step two are as follows: Dialkylphosphine acid is dissolved in anhydrous ethanol with a concentration of ≥99% in a water bath at 70-75℃, and then purified by static crystallization at 0-4℃ for 6-8 hours. After vacuum filtration and washing the crystals 2-3 times with anhydrous ethanol of the same concentration pre-cooled to 0-4℃, the crystals are dried at 55-60℃ and a vacuum degree of -0.09~-0.08MPa for 2-3 hours to obtain white dialkylphosphine acid crystalline solid with a purity of ≥98%.

6. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The pretreatment conditions for step two are as follows: triethanolamine is subjected to dynamic dehydration treatment with 4A molecular sieve for 36-48 hours to reduce its moisture content to ≤0.2%.

7. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The mixing conditions for step three, stage A are as follows: The reaction is carried out at 45-50℃ and 200-300 rpm for 40-50 minutes, during which the system changes from turbid to a homogeneous, light yellow, transparent liquid. The chemical formula for the saponification reaction occurring during this process is: In the formula, This indicates the long-chain fatty acid components contained in the oxidized paraffin mixture, among which... The number of carbon atoms is mainly alkyl chain, It refers to triethanolamine. This indicates the triethanolamine fatty acid salt produced in the reaction. It is generated as a trace byproduct.

8. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The mixing conditions for step four, stage B are as follows: maintain the temperature at 40-45℃, gradually increase the rotation speed to 800-1000 rpm in a phased gradient speed-up mode, and shear emulsify for 50-60 minutes to form a stable oil-in-water emulsion.

9. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The mixing conditions for step five, stage C are as follows: mix for 20-25 minutes at 22-25℃ and 300-400 rpm to obtain a uniform, amber-colored, semi-transparent liquid.

10. The process for preparing a composite collector for low-temperature spodumene flotation according to claim 1, characterized in that, The composite collector is used in low-temperature spodumene flotation to selectively collect spodumene minerals in a low-temperature slurry environment of 5-15℃.

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