A flotation collector and a preparation method and application thereof

Abstract

The present application relates to a kind of floatation collector and its preparation method and application, belong to mineral processing technical field, solve the collector for the flotation of existing technology in oxide mineral to the low recovery rate of mineral, poor temperature resistance, environmental pollution, high energy consumption problem.The present application floatation collector is the compound shown in formula (1):Wherein n=7, 9 or 11.The compound is the cationic functional group compound containing two carboxyl groups and two amine groups, has higher polarity, can enhance the adsorption between collector and mineral surface functional group;At low temperature, it has good water solubility and dispersibility, help to improve the recovery rate of collector at low temperature;With the compound suitable carbon chain length, can realize flotation in wide temperature range, energy saving and carbon reduction;Polar group makes collector molecule can occur chelation with metal cation, enhances mineral recovery rate, and realizes the selective collection of metal ions in hard water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mineral processing, and in particular to a flotation collector and a preparation method and application thereof. BACKGROUND

[0002] At present, the flotation of oxidized minerals mainly uses fatty acid collectors, which have the advantages of economy, high efficiency, and low dosage.

[0003] There are two typical methods for the flotation of oxidized minerals: one is direct flotation using cationic amine collectors, such as primary amines and their corresponding acetic acid or chlorine derivatives, etc., but the cationic amine collectors can cause certain harm to the environment, and there are problems such as high foam viscosity and difficulty in defoaming during use; the other is to first activate the oxidized minerals with multivalent metal ions (such as calcium and magnesium ions), and then use anionic collectors for flotation, such as fatty acids, oxidized paraffin soaps, and tall oil, etc. Since long-chain fatty acids and their salts are widely available and low in cost, they are widely used in the flotation of oxidized minerals in industry. However, the solubility and dispersibility of such collectors are greatly affected by temperature, and they are very sensitive to the temperature of the ore slurry. At low temperatures (less than 20℃), the water solubility and dispersibility are poor, which affects the flotation recovery rate. When used at low temperatures, the ore slurry often needs to be heated to improve its collecting ability, which increases the energy consumption and cost of the flotation process, and is not conducive to environmental protection and energy saving and carbon reduction.

[0004] In view of the problems encountered in the flotation of oxidized minerals using traditional anionic fatty acid collectors, there is an urgent need for a temperature-insensitive and environmentally friendly collector to improve the water solubility and dispersibility of the collector at low temperatures, improve the collecting ability of the collector for oxidized minerals at low temperatures, and realize mineral flotation in a wider flotation temperature range, thereby saving energy and reducing carbon emissions and energy consumption. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide a flotation collector and a preparation method and application thereof to solve at least one of the problems of low recovery rate of minerals, poor temperature resistance, environmental pollution, and high energy consumption of the collectors used for the flotation of oxidized minerals in the prior art.

[0006] In a first aspect, the present application provides a flotation collector, which is a compound represented by formula (1):

[0007] wherein n = 7, 9 or 11.

[0008] Further, the compound is 2-[(5-amino-5-carboxymethyl)amino]lauric acid, which has a chemical structure represented by formula (2):

[0009]

[0010] Further, the compound is 2-[(5-amino-5-carboxymethyl)amino]tetradecanoic acid, having a chemical structure shown in formula (3):

[0011]

[0012] Further, the compound is 2-[(5-amino-5-carboxymethyl)amino]tetradecanoic acid, having a chemical structure shown in formula (3):

[0013]

[0014] In a second aspect, the present application provides a preparation method of a collector, the preparation method comprising: reacting a fatty acid with a halogenating agent to obtain an α-halo fatty acid; and reacting the α-halo fatty acid with lysine.

[0015] Further, the halogenating agent is one of liquid bromine, N-bromosuccinimide, chlorine, and N-chlorosuccinimide.

[0016] Further, the reaction of the α-halo fatty acid with lysine comprises: dissolving lysine in an alkaline solution, adding the α-halo fatty acid, and reacting.

[0017] Further, the alkaline solution is at least one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, and calcium hydroxide aqueous solution.

[0018] In a third aspect, the present application provides an application of a collector in flotation of oxidized minerals, wherein the collector is the collector of the first aspect or the collector obtained by the method of the second aspect.

[0019] Further, the oxidized mineral is one or more of quartz, iron ore, calcite, apatite, fluorite, and scheelite.

[0020] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0021] 1、The flotation collector of the present application contains two carboxyl groups and two amine groups, compared with traditional anionic fatty acid collectors, has stronger polarity, is more likely to form hydrogen bonds or electrostatic interactions with the surface of oxidized minerals, and is adsorbed on the surface of the minerals; and the solubility and dispersibility of the collector in water are improved, the collector can be well dissolved in water at low temperature without heating, the flotation performance at low temperature (as low as 10 DEG C) is ensured, and the collector can realize flotation in a wide temperature range with a suitable carbon chain length of the collector; when the collector is 2-[(5-amino-5-carboxymethyl) amino] lauric acid and the concentration is 80 mg / L, the quartz has good flotation effect in the range of 10-40 DEG C, and the quartz recovery rate is 80-95%.

[0022] 2、The flotation collector of the present application contains carboxyl and amine functional groups, is easy to chelate with metal cations, and the metal ions on the surface of oxidized minerals become active sites for flotation, so when the collector is applied to hard water environment with rich metal cations, not only the selective collection of metal ions can be realized, but also the binding strength of the collector to the mineral surface can be enhanced, and the flotation of the mineral is promoted.

[0023] 3、The non-polar group of the amino acid collector of the present application is a hydrocarbon group, has hydrophobic properties, and the hydrocarbon group of the collector adsorbed on the surface of the mineral enhances the hydrophobicity of the mineral surface, so that the mineral particles are more easily captured by bubbles and rise to the water surface. The carbon chain length of the hydrocarbon group is within a certain range, and as the carbon chain length increases, the collection effect of the fatty acid is improved. However, this effect is not infinite, and the increase of the carbon chain length should be within a suitable range, and the range of the present application is between C10 and C14. If the carbon chain length exceeds this range, although the hydrophobicity of the collector continues to increase, the solubility will decrease, and the collection ability will be weakened.

[0024] 4、The preparation process of the collector of the present application is simple, the process conditions are low, and the collector is easy to prepare and synthesize; the raw material contains lysine, is environment-friendly, and does not need post-treatment; and the prepared amino acid collector has low toxicity, low volatility and biodegradability, and is environment-friendly.

[0025] 5、The flotation collector of the present application can be well dissolved and dispersed in water at low temperature without heating, reduces the amount of the collector while ensuring the flotation efficiency of the collector at low temperature, expands the regional application range of the collector, realizes energy saving and carbon reduction, reduces energy consumption, and reduces the impact of the amount of the collector on the environment.

[0026] The technical solutions in the present application can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the following description, and some advantages will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. The objects and other advantages of the present application can be realized and obtained by the contents particularly indicated in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated herein and constitute a part of the detailed description. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0028] Figure 1 Infrared spectrum characterization results of the collector 2-[(5-amino-5-carboxymethyl)amino] lauric acid prepared for Example 1;

[0029] Figure 2 High-resolution mass spectrum characterization results of the collector 2-[(5-amino-5-carboxymethyl)amino] lauric acid prepared for Example 1;

[0030] Figure 3 Process schematic diagram of the collector 2-[(5-amino-5-carboxymethyl)amino] lauric acid prepared for Example 1;

[0031] Figure 4 The quartz flotation recovery rate changes with pH at 25℃ when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL), respectively;

[0032] Figure 5 The quartz flotation recovery rate changes with the collector addition amount at 25℃ when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL), respectively;

[0033] Figure 6 The quartz flotation recovery rate changes with temperature at pH = 11.5 when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL), respectively;

[0034] Figure 7 The quartz flotation recovery rate changes with pH at 10℃ when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL), respectively;

[0035] Figure 8 The quartz flotation recovery rate changes with the collector addition amount at 10℃ when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL), respectively. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present application will be described in detail below with reference to the drawings, in which the figures constitute a part of the present application and illustrate the principles of the present application together with the embodiments of the present application, but are not intended to limit the scope of the present application.

[0037] At present, the flotation of oxidized minerals mainly uses anionic fatty acid collectors, and the solubility and dispersibility of the traditional fatty acid collectors are greatly affected by temperature, and are very sensitive to the temperature of the ore pulp. Under low temperature conditions (less than 20℃), the water solubility and dispersibility are relatively poor, which affects the flotation recovery rate. Under low temperature conditions, the ore pulp often needs to be heated to improve its collecting ability, which will increase the energy consumption and cost of the flotation process, and is not conducive to energy saving and carbon reduction. In addition, the traditional fatty acid collectors will cause certain harm to the environment during use.

[0038] Therefore, the present application provides a flotation collector, which is a compound represented by formula (1):

[0039] wherein n = 7, 9 or 11. Compared with the prior art, the amino acid collector represented by formula (1) provided by the present application contains two carboxyl groups and two amine groups, has strong polarity, can not only form hydrogen bonds or electrostatic interactions with the surface of the mineral and be adsorbed on the surface of the mineral, but also improve the solubility and dispersibility in water, and can be well dissolved in water at low temperature without heating, thereby ensuring the flotation performance at low temperature (less than 20℃), and cooperating with the appropriate carbon chain length of the collector, the collector can realize flotation in a wide range of flotation temperatures.

[0040] When the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid, the flotation effect of quartz is as follows: Figure 6 It can be seen that when the concentration of ADA is 80 mg / L, the quartz has good flotation effect in the range of 10-40℃, and the quartz recovery rate is 80-95%.

[0041] The flotation collector of the present application contains carboxyl and amine functional groups, which can easily chelate with metal cations, and the metal ions become active sites for flotation. Therefore, when applied to a hard water environment with rich metal cations, not only can the collector selectively collect metal ions, but also can enhance the binding strength of the collector and the mineral surface, and promote the flotation of the mineral.

[0042] The non-polar group of the amino acid type collector is a hydrocarbon group, which has hydrophobic property, and the hydrocarbon group of the collector adsorbed on the surface of the mineral enhances the hydrophobicity of the surface of the mineral, so that the mineral particles are more easily captured by the bubbles and rise to the water surface. The length of the carbon chain of the hydrocarbon group is within a certain range, and with the increase of the length of the carbon chain, the collecting effect of the fatty acid is improved. However, this effect is not infinite, and the increase of the length of the carbon chain should be within a suitable range, and the range of the present application is between C10 and C14. If the length of the carbon chain exceeds this range, although the hydrophobicity of the collector continues to increase, the solubility will decrease, and the collecting ability will be weakened.

[0043] The flotation collector of the present application can be well dissolved in water at low temperature without heating, which ensures the flotation ability under low temperature conditions, realizes energy saving and carbon reduction, and reduces energy consumption; the preparation process of the flotation collector uses lysine, which is friendly to the environment and does not need post-treatment; and the prepared amino acid type collector has low toxicity, low volatility and biodegradability, and is friendly to the environment.

[0044] According to a preferred embodiment of the present application, the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA), and the chemical structure is shown in formula (2):

[0045]

[0046] According to a preferred embodiment of the present application, the collector is 2-[(5-amino-5-carboxymethyl)amino] tetradecanoic acid, and the chemical structure is shown in formula (3):

[0047]

[0048] According to a preferred embodiment of the present application, the collector is 2-[(5-amino-5-carboxymethyl)amino] decanoic acid, and the chemical structure is shown in formula (4):

[0049]

[0050] The chemical structure of the collector is characterized by infrared spectroscopy and mass spectrometry.

[0051] The present application provides a method for preparing the collector of the first aspect, and the method comprises:

[0052] (1) reacting a fatty acid with a halogenating reagent to obtain an alpha-halo fatty acid;

[0053] (2) reacting the alpha-halo fatty acid with lysine;

[0054] The fatty acid is one or more of n-decanoic acid, dodecanoic acid and tetradecanoic acid.

[0055] The reagent for halogenating the fatty acid can be one of liquid bromine, N-bromosuccinimide, chlorine, and N-chlorosuccinimide. Different halogenating reagents require different conditions for reaction with the fatty acid, and different degrees of difficulty in separating the product after the reaction and treating the waste liquid.

[0056] In view of simplifying the process route, improving the selectivity of the α-halogenated fatty acid, and making the product easy to separate, the present application preferably uses liquid bromine to brominate the fatty acid by the Hell-Volhard-Zelinsky method (HVZ) to obtain an α-brominated fatty acid. Under the action of a catalyst, the α-hydrogen of the fatty acid is replaced by bromine to form an α-brominated fatty acid. Selecting phosphorus trichloride or / and phosphorus tribromide as the catalyst can promote the conversion of the carboxylic acid, and then generate the α-brominated fatty acid through a nucleophilic substitution reaction, but excessive catalyst can cause side reactions. Through multiple tests, it is found that when the mass of the catalyst is 3-5% of the mass of the fatty acid, the reaction efficiency is relatively high.

[0057] In order to improve the yield of the α-brominated fatty acid, the molar ratio of the fatty acid to liquid bromine is 1:(1.05-1.1). A slight excess of bromine can ensure that the fatty acid is fully reacted to generate a monobrominated acid, but the amount of bromine added should not be too large, otherwise side reactions will occur, which is not conducive to the removal of residual liquid bromine in the subsequent link.

[0058] Specifically, in order to improve the reaction efficiency and according to the reaction mechanism of the HVZ method, the step (1) can be subdivided into the following two steps:

[0059] (a) heating the fatty acid to completely melt, continuing to heat, adding a catalyst, stirring and reacting;

[0060] (b) further increasing the temperature of the reaction system of step (a) to a certain temperature, adding liquid bromine, and continuing to stir to make the bromine fully react.

[0061] Specifically, in step (a), the fatty acid is heated to completely melt, and the heating time is controlled to be appropriate for completely melting the fatty acid. According to one preferred embodiment of the present application, the temperature for melting dodecanoic acid is 75-95°C, and more preferably 75°C.

[0062] Specifically, in step (a), the temperature after continuing to heat is the temperature at which the fatty acid is converted into a halogenated enol in the presence of a catalyst. According to one preferred embodiment of the present application, when the fatty acid is dodecanoic acid, the temperature after continuing to heat can be controlled to be 85-95°C, and preferably 85°C.

[0063] Specifically, in step (b), a high reaction temperature and a long reaction time are required after the addition of bromine, and both a too low reaction temperature and a too short reaction time are not conducive to the improvement of the yield of the reactant, while a too high temperature can lead to the elimination of hydrogen bromide in the product to generate an α, β-unsaturated carboxylic acid, and also can make the yield of the α-bromofatty acid decrease; a too long reaction time can increase the energy consumption. Therefore, the temperature is preferably selected to be 95-105°C, and the reaction time is preferably controlled to be more than 5h, and more preferably 4-6h.

[0064] The present application also includes a step of purifying the α-bromofatty acid prepared in step (1), which is actually to remove the unreacted liquid bromine and neutralize the small amount of residual bromine in the reaction system. The specific operation is as follows: the residual liquid bromine in the container is extracted by a vacuum pump, and when the reaction material is light yellow, the air extraction is stopped, and a certain amount of sodium sulfite solution is added to neutralize the unreacted liquid bromine; after adding pure water to the reaction liquid, the reaction liquid is moved to a separatory funnel to separate the lower water layer, and the upper organic liquid is separated to obtain a light yellow liquid or a milky white liquid, which is an α-bromofatty acid. In specific implementation, other substances can also be used to neutralize the liquid bromine, as long as they can neutralize and do not produce other harmful substances.

[0065] The acylation reaction between the α-halo fatty acid and the lysine is irreversible, and halogenated hydrogen is generated in the reaction, which can form a salt with amines, so that the acylation reaction between the α-halo fatty acid and the lysine is difficult to proceed again. Therefore, the reaction needs to be carried out in the presence of an alkaline reagent. The alkaline reagent neutralizes the halogenated hydrogen and does not affect the acylation reaction described in the present application, such as sodium hydroxide, sodium carbonate, sodium carbonate, sodium bicarbonate, calcium hydroxide, etc., so that the lysine can fully react.

[0066] Specifically, in order to improve the reaction efficiency, the step (2) of the collector preparation method of the present application specifically includes: dissolving the lysine in an alkaline solution, adding the α-halo fatty acid prepared in step (1), and reacting; wherein the alkaline solution is at least one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, and calcium hydroxide aqueous solution.

[0067] Although the alkaline reagent can promote the acylation reaction between the α-halo fatty acid and the lysine by neutralizing the generated halogenated hydrogen, the stronger the alkalinity, the more likely the α-halo fatty acid to undergo hydrolysis reaction to generate byproduct α-hydroxydodecanoic acid, which is not conducive to the acylation reaction of the present application. Therefore, the present application needs to limit the amount of the alkaline reagent.

[0068] Specifically, the molar ratio of the lysine to the solute in the alkaline solution is 1:(0.4-0.6).

[0069] In step (2) of the present application, the molar ratio of the halogenated fatty acid to lysine is 1: (1.1-1.2), and a slight excess of lysine can ensure that the bromoalkyl acid is fully reacted, but the amount of addition should not be too much, otherwise it is not conducive to the subsequent product purification.

[0070] In order to ensure the smooth progress of the reaction and obtain high-quality products, step (2) needs to be carried out at an appropriate temperature range.

[0071] Specifically, the temperature for step (2) to carry out the reaction is 95-110℃, and the time is 4-6h. If the temperature is too high, side reactions may occur in the reaction system, such as the formation of α, β-unsaturated carboxylic acid, which reduces the yield and purity of the target product; the halogenated fatty acid is not stable at high temperature and is prone to decomposition, thereby reducing the yield of the target product. According to a preferred embodiment of the present application, the temperature for step (2) to carry out the reaction is 95℃, and the time is 5h.

[0072] The chemical reaction process for preparing 2-[(5-amino-5-carboxymethyl) amino] lauric acid (ADA) by using dodecanoic acid and lysine as raw materials is shown in the following reaction equation: Figure 3 When decane or tetradecanoic acid is used to react with lysine, due to the similarity in structure and properties of fatty acids with different carbon chain lengths, the synthesis method of α-halogenated dodecanoic acid and the acylation reaction method thereof with lysine are also applicable. However, due to the change in carbon chain length, in order to improve the reaction efficiency, part of the reaction conditions need to be adjusted, mainly the reaction temperature which has a greater impact on the reaction.

[0073] The present application also includes a step of purifying the product prepared in step (2), specifically: transferring the reaction product into a separatory funnel, adding water to extract three times to obtain a light yellow product, and removing excess water by normal pressure distillation at 60-90℃ for 8-12h. The by-product halide salt generated during the preparation process is easily soluble in water, and the generated halide salt is removed by extraction, and then dried to obtain the pure final product.

[0074] The present application also provides the use of the collector of the first aspect or the collector obtained from the second aspect in the flotation of oxidized minerals.

[0075] Specifically, the method of applying the collector to the flotation of oxidized minerals comprises:

[0076] (1) slurry preparation of the mineral sample to be treated to obtain a mineral slurry;

[0077] (2) adjusting the pH of the mineral slurry and adding the flotation collector;

[0078] (3) aeration flotation.

[0079] Preferably, in step (1), the mass concentration of the ore sample in the pulp after sizing is 5-10%, the lower the mass concentration, the better the effect of the flotation; but it is not advisable to be reduced unlimitedly, which will lead to the increase of production cost and the decrease of production efficiency.

[0080] Preferably, the particle size of the ore sample in the pulp is 38-74 μm, if the particle size of the ore sample is too large, the contact area between the ore and the reagent will be reduced, the flotation speed will be slow, and even the target mineral cannot be floated; if the particle size of the ore sample is too small, the dosage of the reagent will be increased, the flotation cost will be increased, and the mud phenomenon will be caused, which will reduce the flotation performance of the ore.

[0081] The pH value of the pulp has a significant influence on the flotation performance of the collector, under different pH value conditions, the solubility, dispersibility and the action with the mineral surface of the collector will be changed, which will further affect the flotation effect. Therefore, in step (2), the pH of the pulp is adjusted by using acid or alkali to adapt to the flotation of the mineral by different collectors in different pulps.

[0082] According to one preferred embodiment of the present application, when 2-[(5-amino-5-carboxymethyl)amino]lauric acid (ADA) is used as the collector for the flotation of quartz ore, the pH value of the pulp is adjusted to neutral or alkaline, specifically 7-14, preferably 10-13, which is beneficial to the collection of the mineral quartz by the ADA collector. Quartz is a silicon oxide, under neutral or alkaline conditions, its surface has a negative charge, and the added amino acid collector will be subjected to the electrostatic attraction of the quartz surface, so as to be adsorbed on the surface of the quartz, and this adsorption is a type of physical adsorption.

[0083] The dosage of the collector is an important parameter in the flotation process, which directly affects the flotation efficiency and selectivity. The dosage of the collector needs to be adjusted according to the pH value of the pulp, the temperature, the mineral properties, and other additives used in the flotation.

[0084] According to one preferred embodiment of the present application, when ADA is used as the collector for the flotation of quartz ore, and the pH value of the pulp is adjusted to alkaline, in step (2), the concentration of the flotation collector in the pulp is 20-100 mg / L, preferably 60-90 mg / L. The adsorption of the collector on the surface of the mineral is closely related to the actual flotation mechanism, the flotation mechanism refers to the basic way of the adsorption of the molecules or ions of the collector on the mineral-water interface, mainly including electrostatic adsorption, hydrogen bond adsorption, semi-micelle adsorption, and the adsorption of the reaction products of the collector on the surface of the mineral, etc., the too low dosage of the collector may lead to the decrease of the recovery rate of the target mineral, and the too high dosage of the collector may lead to the incorrect collection of too much gangue mineral, which also affects the recovery rate.

[0085] From Figure 5 , Figure 8It can be seen that the flotation recovery rate increases significantly with the increase of the concentration of the collector in the range of 20-90 mg / L; when the concentration reaches a certain value, the increase of the recovery rate with the increase of the concentration becomes smaller, and the optimal concentration is 80 mg / L; when the concentration of the collector is too high, the flotation recovery rate decreases; and in the flotation method of the present application, the optimal concentration of the collector is 80 mg / L at 10℃ and 25℃, which shows that the flotation method of the present application is not sensitive to temperature.

[0086] The flotation temperature also has an important influence on the flotation process. The temperature of the ore pulp can affect the solubility of the collector, the wettability of the mineral surface, the chemical reaction rate of the flotation process, the selectivity to the flotation mineral, the selectivity of the flotation foam, etc.

[0087] According to a preferred embodiment of the present application, the temperature of the aeration flotation is 10-40℃, preferably 10-25℃. The amine group and the carboxyl group in the chemical structure of the flotation collector of the present application increase the polarity of the collector, improve the water solubility and dispersibility of the collector at low temperature, and broaden the temperature range of the flotation of the ore pulp by the collector; however, the temperature cannot be too low, and too low temperature can also affect the solubility and collecting ability of the amino acid collector. If the flotation temperature is too high, the ore pulp needs to be heated, which increases the energy consumption. When the concentration of the ADA collector is 80 mg / L and the pH of the ore pulp is 11.5, the recovery rate of the quartz in the quartz ore by the ADA collector can be more than 90% at 10℃.

[0088] Further, in order to improve the collecting efficiency, the step (2) further comprises adding an activator (Ca 2 + , Mg 2+ , Ba 2+ , etc.) to the ore pulp.

[0089] Specifically, the activator activates the mineral to form an activation site on the surface of the mineral, and the double carboxyl group in the collector molecule has nucleophilicity and can form a stable complex with metal ions. In the flotation process, this chelation can increase the adsorption between the mineral surface and the flotation reagent, not only improving the flotation performance of the mineral, but also realizing the selective adsorption of the mineral with metal ion active sites on the surface.

[0090] Further, in order to improve the flotation recovery rate of the mineral, the concentration of the activator in the ore pulp of the present application is 0-60 mg / L. If the concentration of the activator is too small, the mineral may not be effectively activated, resulting in a decrease in the recovery rate; and if the concentration of the activator is too large, too much collector may be consumed or a precipitate that is not conducive to flotation may be formed on the surface of the mineral.

[0091] In order to reduce the floatability of some minerals in the ore pulp and realize selective flotation, the step (2) further comprises adding an inhibitor to the ore pulp. When performing the collecting flotation on the quartz in the ore sample, in order to avoid the iron-containing minerals in the ore sample from being floated, a starch inhibitor can be added to the ore sample to increase the hydrophilicity of the surface of the iron-containing minerals, thereby inhibiting the collection of the iron-containing minerals. When inhibiting the flotation of other oxide minerals, a corresponding inhibitor can be sought.

[0092] It should be noted that by adjusting the specific flotation condition parameters, the amino acid collector of the present application can be applied to the selective collection and flotation of calcite, apatite, fluorite, and scheelite in addition to the flotation of quartz.

[0093] Example 1

[0094] The preparation method of 2-[(5-amino-5-carboxymethyl)amino] lauric acid comprises:

[0095] (1) 0.5 mol of dodecyl acid is weighed and added to a 250 mL three-necked flask equipped with a stirrer, a thermometer, and a spherical condenser reflux tube, and is placed in a 75°C constant temperature water bath kettle for heating and melting. After the temperature is continuously increased to 85°C, the stirrer is turned on, and a catalyst phosphorus trichloride (PCl3) is added. The constant temperature stirring is performed for 1 h;

[0096] (2) The temperature of the reaction system in step (1) is increased to 95°C, 0.525 mol of liquid bromine is added to the system, and the constant pressure separatory funnel is used for slow dropwise addition to the reaction system. The stirring is fast, the dropwise addition time is controlled to be 6 h, and the stirring reaction is continuously performed for 5 h to make the liquid bromine fully react;

[0097] After the reaction is completed, the remaining liquid bromine in the three-necked flask is extracted by a vacuum pump. When the reaction material is light yellow, the air extraction is stopped, and a certain amount of sodium sulfite solution is added to neutralize the unreacted liquid bromine. Pure water is added to the reaction liquid, the reaction liquid is moved to a separatory funnel to separate the lower water layer, and the upper organic liquid is separated to obtain a light yellow liquid or a milky white liquid, which is 2-bromododecanoic acid;

[0098] (3) 2-bromododecanoic acid and lysine are added to a 250 mL three-necked flask equipped with a stirrer, a thermometer, and a spherical condenser reflux tube in a proportion of 1:1.15, deionized water is added, the temperature is increased to 95°C in a water bath kettle, and the constant temperature reaction is performed for 5 h;

[0099] After the reaction is completed, the reaction product is transferred to a 250 ml separatory funnel, extracted with water three times to obtain a light yellow product, and the excess water is removed by atmospheric distillation at 70°C for 10 h to obtain the final product 1.

[0100] The spectrum obtained by performing infrared spectrum testing on the product 1 is as shown in the following figure. Figure 1The infrared spectrum of the product 1 is shown in Figure 1. The spectrum shows the vibration absorption peaks of secondary amine group and carboxyl group at 3430 cm -1 , 1625 cm -1 , which indicates that the bromination and substitution reactions in the preparation process are successfully completed. The spectrum shows the vibration absorption peak of primary amine group at 1563 cm -1 , which indicates that only one of the two amine groups of lysine has reacted with the α-halo fatty acid. The amine group at the end of the side chain of lysine has high reactivity and can chemically react with carboxylic acid to form amide bond, so the α-halo fatty acid reacts with the amine group on the side chain of lysine.

[0101] Figure 2 The mass spectrum results of the product 1 are shown in Figure 1, which are obtained by ESI ionization source (solvent: methanol; mode: positive ion). The results show the adduct ion peaks of [M+H]-, [M+Na]-, and [M+K]-, which indicates that the 2-[(5-amino-5-carboxymethyl)amino] lauric acid is successfully synthesized.

[0102] Through the calculation of the amount of substance before and after the reaction, the yield of the product of Example 1 is 62%.

[0103] Example 2

[0104] The same preparation method as in Example 1 is used, except that the amount of phosphorus trichloride catalyst added in step (1) is 3 g, and the final product 2 is obtained.

[0105] The product 2 is subjected to infrared spectrum test and mass spectrum test by ESI ionization source, and the test results show that Example 2 successfully synthesizes 2-[(5-amino-5-carboxymethyl)amino] lauric acid.

[0106] Through the calculation of the amount of substance before and after the reaction, the yield of the product of Example 2 is 52%.

[0107] Example 3

[0108] The same preparation method as in Example 1 is used, except that the temperature of the reaction system in step (2) is increased to 105°C, and the final product 3 is obtained.

[0109] The product 3 is subjected to infrared spectrum test and mass spectrum test by ESI ionization source, and the test results show that Example 3 successfully synthesizes 2-[(5-amino-5-carboxymethyl)amino] lauric acid.

[0110] Through the calculation of the amount of substance before and after the reaction, the yield of the product of Example 3 is 48%.

[0111] Example 4

[0112] The same preparation method as in Example 1 was used, except that in step (2), the amount of liquid bromine added was 0.55 mol, to obtain the final product 4.

[0113] Product 4 was subjected to infrared spectrum test and mass spectrum test with ESI as ionization source, and from the test results obtained, it was concluded that Example 4 successfully synthesized 2-[(5-amino-5-carboxymethyl)amino] lauric acid.

[0114] Through calculation of the amount of substance before and after the reaction, it was obtained that the yield of the product of Example 4 was 50%.

[0115] Example 5

[0116] The same preparation method as in Example 1 was used, except that in step (3), the molar ratio of 2-bromododecanoic acid: lysine: sodium hydroxide was 1:1.15:0.69, to obtain the final product 5.

[0117] Product 5 was subjected to infrared spectrum test and mass spectrum test with ESI as ionization source, and from the test results obtained, it was concluded that Example 5 successfully synthesized 2-[(5-amino-5-carboxymethyl)amino] lauric acid.

[0118] Through calculation of the amount of substance before and after the reaction, it was obtained that the yield of the product of Example 5 was 45%.

[0119] Example 6

[0120] The same preparation method as in Example 1 was used, except that in step (3), the temperature of the water bath was raised to 110°C, to obtain the final product 6.

[0121] Product 6 was subjected to infrared spectrum test and mass spectrum test with ESI as ionization source, and from the test results obtained, it was concluded that Example 6 successfully synthesized 2-[(5-amino-5-carboxymethyl)amino] lauric acid.

[0122] Through calculation of the amount of substance before and after the reaction, it was obtained that the yield of the product of Example 6 was 55%.

[0123] Example 7

[0124] The same preparation method as in Example 1 was used, except that the dodecyl acid in Example 1 was replaced by tetradecyl acid, to obtain the final product 7.

[0125] Product 7 was subjected to infrared spectrum test and mass spectrum test with ESI as ionization source, and from the test results obtained, it was concluded that Example 7 successfully synthesized 2-[(5-amino-5-carboxymethyl)amino] tetradecanoic acid.

[0126] Through calculation of the amount of substance before and after the reaction, it was obtained that the yield of the product of Example 7 was 60%.

[0127] Example 8

[0128] The same preparation method as in Example 1 was adopted, except that the dodecyl acid in Example 1 was replaced by n-decanoic acid, to obtain the final product 8.

[0129] Product 8 was subjected to infrared spectrum test and mass spectrum test with ESI as ionization source, and from the test results obtained, it was concluded that Example 8 successfully synthesized 2-[(5-amino-5-carboxymethyl) amino] decanoic acid.

[0130] Through the calculation of the amount of substance before and after the reaction, the yield of the product of Example 8 was 58%.

[0131] Comparative Example 1

[0132] The same method as in Example 1 was adopted, except that the reaction temperature of 2-bromododecanoic acid with lysine was 120℃, and the product obtained was brown, indicating that the product preparation failed.

[0133] Application Example 1

[0134] In this embodiment, the quartz is taken from Anshan area in Liaoning Province, China, and the purity of the ore sample is above 96%. In this embodiment, single mineral flotation experiment is carried out on the quartz, and the particle size of the flotation ore sample is 37-74 μm, and the flotation temperature is 25℃ and 10℃, respectively.

[0135] The specific implementation steps include:

[0136] (1) 2g of the ore sample to be treated was added into a 40mL flotation cell, 38mL of ultrapure water was added, and the slurry was adjusted for 2min;

[0137] (2) A pH adjuster was added to the ore slurry to adjust the pH to a predetermined value;

[0138] (3) Calcium chloride was added to the ore slurry prepared in step (2) as an activator, and stirred for 2min, and then sodium oleate was added as a collector to obtain ore slurry 1;

[0139] 2-[(5-amino-5-carboxymethyl) amino] lauric acid (ADA) was directly added to the ore slurry prepared in step (2) as a collector to obtain ore slurry 2;

[0140] (4) Ore slurry 1 and ore slurry 2 were stirred for 2min, respectively, and subjected to aeration flotation, and the flotation time was 2min;

[0141] (5) After the flotation was completed, the froth product, i.e. the concentrate, and the product in the cell were filtered, dried, weighed, and the flotation recovery rate was calculated.

[0142] Figure 4The results show the quartz flotation recovery rate as a function of pH at a temperature of 25°C with the collectors 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL) respectively. From the results, it can be seen that in the acidic to neutral range, the collecting effect of ADA and sodium oleate is not significant; as the pH value increases, the collecting ability of ADA and sodium oleate gradually increases; when the pH value exceeds 11, the collecting effect begins to weaken. This indicates that an alkaline environment is conducive to the collection of the two collectors, and the collecting effect of ADA is more significant than that of sodium oleate in an alkaline condition; there is an optimal pH range, about 11-13, and the collecting efficiency will decrease to below 80% when the range is exceeded. Figure 3

[0143] The results show the quartz flotation recovery rate as a function of pH at a temperature of 25°C with the collectors 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL) respectively. From the results, it can be seen that in the acidic to neutral range, the collecting effect of ADA and sodium oleate is not significant; as the pH value increases, the collecting ability of ADA and sodium oleate gradually increases; when the pH value exceeds 11, the collecting effect begins to weaken. This indicates that an alkaline environment is conducive to the collection of the two collectors, and the collecting effect of ADA is more significant than that of sodium oleate in an alkaline condition; there is an optimal pH range, about 11-13, and the collecting efficiency will decrease to below 80% when the range is exceeded. Figure 5 Figure 5 The results show the quartz flotation recovery rate as a function of pH at a temperature of 25°C with the collectors 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL) respectively. From the results, it can be seen that in the acidic to neutral range, the collecting effect of ADA and sodium oleate is not significant; as the pH value increases, the collecting ability of ADA and sodium oleate gradually increases; when the pH value exceeds 11, the collecting effect begins to weaken. This indicates that an alkaline environment is conducive to the collection of the two collectors, and the collecting effect of ADA is more significant than that of sodium oleate in an alkaline condition; there is an optimal pH range, about 11-13, and the collecting efficiency will decrease to below 80% when the range is exceeded.

[0144] Figure 6 Figure 6 The results show the quartz flotation recovery rate as a function of pH at a temperature of 25°C with the collectors 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) and sodium oleate (NaOL) respectively. From the results, it can be seen that in the acidic to neutral range, the collecting effect of ADA and sodium oleate is not significant; as the pH value increases, the collecting ability of ADA and sodium oleate gradually increases; when the pH value exceeds 11, the collecting effect begins to weaken. This indicates that an alkaline environment is conducive to the collection of the two collectors, and the collecting effect of ADA is more significant than that of sodium oleate in an alkaline condition; there is an optimal pH range, about 11-13, and the collecting efficiency will decrease to below 80% when the range is exceeded.

[0145] Figure 7 ​​Fig. 2 is a diagram showing the change of the flotation recovery rate of quartz with pH at 10℃ when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) or sodium oleate (NaOL). Figure 7 It can be seen that the flotation process of sodium oleate and ADA is significantly affected by pH at 10℃. In acidic or neutral environment, the recovery rate of both is not ideal, and the flotation effect is not good. However, when the pH of the solution is increased to the alkaline range, the flotation recovery rate is improved, showing good flotation performance. Especially when the pH reaches 11-13, the flotation effect reaches the best state. In this strong alkaline environment, ADA shows stronger collecting ability than sodium oleate. The experimental data show that when the pH is 12, the recovery rate of ADA is more than 90%, while the recovery rate of sodium oleate is less than 50%. Therefore, under the specific conditions of low temperature 10℃ and alkaline solution, ADA as a collector shows a better flotation effect than sodium oleate. This means that in the case of efficient recovery of specific substances, especially in the face of low-temperature alkaline environment, the use of ADA as a collector may be more effective.

[0146] Figure 8 Fig. 3 is a diagram showing the change of the flotation recovery rate of quartz with the amount of collector at 10℃ when the collector is 2-[(5-amino-5-carboxymethyl)amino] lauric acid (ADA) or sodium oleate (NaOL). Figure 8 It can be seen that when the temperature is maintained at 10℃ and the pH of the solution is 11.5, the collecting efficiency of any collector increases with the increase of the dosage. Compared with Figure 5 When the temperature is 25℃, the optimal dosage of the collector is 80mg / L. When the temperature of the ore pulp is reduced to 10℃, the optimal dosage of ADA is still 80mg / L, while the optimal dosage of sodium oleate is increased by 70mg / L. Within the range of 15-90mg / L, the collecting effect of ADA is obviously better than that of sodium oleate. This further confirms the high efficiency and practicability of ADA in the mineral flotation process.

[0147] In addition, from the flotation process and flotation results of the above application examples, Figures 4-8 It can be seen that before using sodium oleate as a collector to float the ore pulp, not only the pH value of the ore pulp needs to be adjusted, but also calcium chloride activator needs to be added to activate the mineral surface to provide active sites for the adsorption of sodium oleate collector, so as to realize flotation. In contrast, before using the collector of the present application to float the ore pulp, only the pH value of the ore pulp needs to be adjusted, and no activator is needed to activate the mineral surface, so that a good flotation recovery rate can be obtained. Therefore, the use of the collector of the present application can simplify the flotation process of the ore pulp, reduce the use of reagents, and reduce the cost. In addition, compared with sodium oleate, the amino acid collector has low toxicity, low volatility and biodegradability, and is environmentally friendly.

[0148] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A flotation collector, characterized in that, The collector is a compound shown in formula (1): wherein n = 7, 9 or 11.

2. The collector of claim 1, wherein The compound is 2-[(5-amino-5-carboxymethyl)amino] lauric acid, having a chemical structure shown in formula (2):

3. The collector of claim 1, wherein The compound is 2-[(5-amino-5-carboxymethyl)amino] tetradecanoic acid, having a chemical structure shown in formula (3):

4. The collector of claim 1, wherein The compound is 2-[(5-amino-5-carboxymethyl)amino] decanoic acid, having a chemical structure shown in formula (4):

5. A process for the preparation of the collector as claimed in any one of claims 1 to 4, characterized in that, The preparation method comprises: reacting a fatty acid with a halogenating agent to obtain an alpha-halo fatty acid; and reacting the alpha-halo fatty acid with lysine.

6. The method of claim 5, wherein, The halogenating agent is one of liquid bromine, N-bromosuccinimide, chlorine, and N-chlorosuccinimide.

7. The method of claim 5, wherein, The reaction of the alpha-halo fatty acid with lysine comprises: dissolving lysine in an alkaline solution, adding the alpha-halo fatty acid, and reacting.

8. The method of claim 7, wherein, The alkaline solution is at least one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, and calcium hydroxide aqueous solution.

9. Use of a collector in the flotation of oxidic minerals, characterized in that, The collector is the collector of any one of claims 1-4 or the collector obtained by any one of claims 5-8.

10. Use according to claim 9, characterized in that, The oxidized mineral is one or more of quartz, iron ore, calcite, apatite, fluorite, and scheelite.

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