Iron ore low-temperature reverse flotation anion collecting agent and preparation method

Abstract

The invention aims to provide an iron ore low-temperature reverse flotation collecting agent and a preparation and use method thereof in order to overcome the defects of an existing flotation production technology. The low-temperature reverse flotation collecting agent for the iron ore is obtained through reaction of fatty acid, alcohols, esters, inorganic alkali and water as raw materials, and the raw materials comprise, by mass, 30%-80% of the fatty acid, 10%-30% of the alcohols, 3%-10% of the esters, 3%-10% of the inorganic alkali and the balance water. The molar ratio of the inorganic base to the fatty acid is (0.5-1): 1. By adjusting the molecular structure and functional groups of the collecting agent, the collecting agent has the characteristics of high collecting capacity, good selectivity, low temperature resistance, good dispersion solubility and environmental protection, and can meet the actual requirements of reverse flotation of lean, impure and fine iron ores at low temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to an anion collector for low-temperature reverse flotation of iron ore and a preparation method thereof. Background Art

[0002] At present, the reverse flotation process is mainly used for domestic lean iron ore. This process often uses fatty acid anions and modified collectors. Such collectors are not well soluble and dispersed in water and need to be heated to 30-45°C for flotation, which not only increases the cost of mineral processing, but also consumes coal and produces a large amount of CO2 gas, affecting the environment. Especially in the north, in the cold winter weather, flotation energy consumption and heat loss are more serious. Therefore, how to improve the low-temperature reverse flotation performance of collectors and solve the problem of heating iron ore flotation is of great significance to improving the efficient utilization of my country's iron ore resources.

[0003] In recent years, there has been more and more research on anionic collectors for low-temperature reverse flotation of iron ore. Many scholars have modified the polar groups of fatty acids and developed a series of modified fatty acid collectors such as halogenated fatty acids, hydroxy fatty acids, and sulfonated fatty acids, which have improved the selectivity and low-temperature resistance of the collectors and enhanced the collection performance.

[0004] Among them, the Chinese journal articles "Development of CW-1 Iron Ore Flotation Collector", "Experimental Study on Iron Ore Reverse Flotation Desiliconization Based on New Low-Temperature Resistant Collectors" and "Experimental Study on New Fatty Acid Collectors in Low-Temperature Flotation Desiliconization of Anshan-type Iron Ore" used ozone-combined catalysts to catalyze the oxidation of oleic acid to synthesize any acid and azelaic acid as collectors, and used a mixture of organic acids and fatty acids after addition and substitution reactions to prepare collectors. The synthesis process is complex, there are many by-products in the reaction, and the reaction time is long. The LKY-1, TA-19, DGT-P and AG-1 collectors developed in the Chinese journal articles "Industrial Experimental Application of LKY-1 Low-Temperature Collector", "Research and Application of Low-Temperature Resistant Collector TA-19 in Lilou Iron Mine", "Research on the Application of New Low-Temperature Collector DGT-P in Reverse Flotation of Qidashan Iron Ore" and "Research on Reverse Flotation Process of Qidashan Concentrator Mixed Magnetic Concentrate with New Low-Temperature Collector" all require a flotation temperature of no less than 20°C. The flotation temperature is still relatively high and cannot meet the requirements of low-temperature flotation in northern winter. Summary of the invention

[0005] The purpose of the present invention is to provide an anion collector for low-temperature reverse flotation of iron ore and a preparation method thereof in view of the problems existing in the existing anion collector for low-temperature reverse flotation of iron ore. By selecting fatty acids with different freezing points and different unsaturation degrees (iodine values), conjugating and compounding with low-carbon fatty alcohols and low-molecular-weight ester substances, introducing hydroxyl groups and ester groups into the agent, the dispersibility, solubility and collection ability of the agent in the low-temperature state are enhanced, and a new collector is synthesized by self-emulsification and saponification, which can be applied to low-temperature reverse flotation of iron ore at 5 to 30°C.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The invention provides an anion collector for low-temperature reverse flotation of iron ore, which is obtained by reacting fatty acids, alcohols, esters, inorganic bases and water as raw materials, wherein the raw materials are composed of the following mass percentages: the total mass percentage is 100%, the fatty acid is 30%-80%, the alcohol mass content is 10%-30%, the ester mass content is 3%-10%, the inorganic base mass content is 3%-10%, the balance is water, and the molar ratio of the inorganic base to the fatty acid is 0.5-1:1;

[0008] The fatty acid is at least one of C13-C18 unsaturated straight-chain or branched fatty acids, with an iodine value of 130-140 and a freezing point of -15-8°C; it can be selected from vegetable oleic acid, animal oleic acid or synthetic fatty acids with a lower freezing point;

[0009] The alcohol is at least one of C2-C10 straight-chain or branched fatty alcohols; it can be selected from at least one of ethanol, isopropanol, n-propanol, ethylene glycol, diethylene glycol, pentanol, hexanol, octanol, etc. with a low freezing point;

[0010] The ester is at least one of methyl benzoate, dimethyl phthalate, methyl acetate, ethyl acetate and butyl acetate;

[0011] The inorganic base is sodium hydroxide or potassium hydroxide, and the molar ratio of the inorganic base to the fatty acid is 0.5 to 1:1. When the molar ratio of the base content to the fatty acid is less than 1, the fatty acid is in a semi-saponified emulsified state, which helps the collector to disperse and dissolve at low temperature.

[0012] The principle of the present invention is: by selecting fatty acids with different freezing points and different unsaturation (iodine value), when the molar ratio with the inorganic base is less than 1, the fatty acid is in a semi-saponified emulsified state, which helps the collector to disperse and dissolve at low temperatures, and is conjugated with low-carbon fatty alcohols and low-molecular-weight ester substances. The hydroxyl group is introduced by alcohols, which increases the interaction between the collector and water molecules, improves the solubility and dispersibility of the agent, and can also enhance the stability of the foam and improve the flotation efficiency. The ester group is introduced by esters, which can improve the surface activity of the collector and improve the selectivity. In alkaline solutions, the hydrogen bonding between the carbonyl oxygen atom and OH- in the ester bond can make the ester form an adsorption layer on the mineral surface, and then improve the capture ability of the collector through electrostatic adsorption, hydrogen bonding and chelation. At the same time, the compounding of the agents after the combination has a synergistic effect, which enhances the capture ability and selectivity of the collector.

[0013] In addition, the present invention also provides a method for preparing the above collector, comprising the following steps:

[0014] 1) At a certain temperature, the fatty acids, alcohols and esters are fully mixed according to the proportions;

[0015] 2) The mixture is heated, and then an inorganic alkali solution with a mass concentration of 5% to 20% is added according to a proportion, stirred and saponified to obtain a collector.

[0016] Furthermore, in the preparation method of the above collector, a condensing device needs to be added to the reactor during the heating saponification process to prevent the alcohol substances from volatilizing.

[0017] Furthermore, in the preparation method of the above-mentioned collector, fatty acids, alcohols and esters need to be mixed first and then saponified, which can improve the solubility and dispersibility of the collector. The reason is that when alcohols and esters are added first, the structure and state of the fatty acids are improved, the critical micelle concentration is reduced, and thus the solubility of the fatty acids and the solubility of the saponification products are improved.

[0018] Furthermore, in the preparation method of the above collector, the saponification temperature is 70-100° C. and the insulation time is 30-90 min.

[0019] Furthermore, in the above-mentioned method for preparing the collector, the container used for preparing the collector is a non-ferrous container;

[0020] Furthermore, in the preparation method of the collector, mechanical stirring is used for stirring, and the stirring speed is controlled at 500 to 3000 rpm.

[0021] The beneficial effects of the present invention are:

[0022] 1. The main raw material of the collector of the present invention is a low freezing point fatty acid, which is in a liquid flow state at low temperatures. The saponified product can still maintain a liquid flow state at low temperatures, has good low temperature dispersibility, and can be configured at low temperatures.

[0023] 2. The low-carbon fatty alcohol added to the low-temperature collector of the present invention has certain foaming properties and can also be used as a solvent to increase the low-temperature dispersibility of the collector. The unsaturated straight-chain and branched-chain fatty acids of C13 to C18 have good selectivity and have a synergistic effect when combined with alcohols and fatty acids, which can enhance the collector's collection ability and selectivity.

[0024] 3. The synthesis process of the collector of the present invention is simple, the raw materials are safe and non-toxic, and the product price is low. Compared with traditional fatty acid collectors, it has the advantages of small dosage, low operating temperature and strong collection ability, which can save energy and reduce flotation costs.

[0025] 4. The collector of the present invention has a wide range of applications, and can be used not only for low-temperature reverse flotation of iron ore at 5 to 30°C, but also for flotation of tungsten ore, cassiterite, fluorite and other ores. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flotation process flow chart of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0028] The following examples use soybean oil fatty acid, rapeseed oil fatty acid, synthetic fatty acid as fatty acids; ethanol, ethylene glycol, isopropanol, methyl acetate, and butyl acetate are all industrial reagents; industrial sodium hydroxide is used as an inorganic base; tap water is used to prepare the alkali solution; and potassium dichromate titration is used to determine the iron grade.

[0029] Example 1

[0030] The invention discloses a low-temperature reverse flotation collector for iron ore. The weight proportion of each raw material is as follows: 30 parts of soybean oil fatty acid, 15 parts of ethanol, 3 parts of methyl acetate and 32 parts of 10% sodium hydroxide solution.

[0031] The preparation method is as follows: ① At 50°C, add soybean oil fatty acid, ethanol and methyl acetate in a stirring barrel in sequence and stir and mix evenly. ② Raise the temperature to 90°C, drop 10% sodium hydroxide solution, stir and mix for 1 hour, and the preparation of liquid fluidized iron ore low temperature collector 1# is completed.

[0032] How to use collector 1#:

[0033] The prepared collector 1# was used for rough separation of red magnetic mixed iron ore with a TFe grade of 48.91%. The flotation process is as follows: Figure 1 As shown, under the condition of flotation temperature of 10°C, NaOH dosage of 900g / t, starch dosage of 800g / t, CaO dosage of 300g / t, collector 1# dosage of 1000g / t, the flotation indicators of concentrate yield of 54.24%, concentrate grade of 68.42% and concentrate recovery rate of 75.81% were obtained in one roughing.

[0034] Example 2

[0035] The invention discloses a low-temperature reverse flotation collector for iron ore. The weight proportion of each raw material is as follows: 30 parts of rapeseed oil acid, 12 parts of ethylene glycol, 3 parts of butyl acetate and 22 parts of 15% sodium hydroxide solution.

[0036] The preparation method is as follows: ① At 50°C, add rapeseed oil fatty acid, ethylene glycol, and butyl acetate in a stirring barrel in sequence and stir and mix evenly. ② Raise the temperature to 90°C, dropwise add 15% sodium hydroxide solution, stir and mix for 1 hour, and the preparation of low-temperature collector 2# is completed.

[0037] How to use collector 2#:

[0038] The prepared collector 2# was used for rough separation of red magnetic mixed iron ore with a TFe grade of 48.92%. The flotation process is as follows: Figure 1 As shown, under the conditions of NaOH dosage 900g / t, starch dosage 800g / t, CaO dosage 300g / t, collector 2# dosage 850g / t, and flotation temperature 20°C, the flotation indicators of concentrate yield 53.88%, concentrate grade 68.35%, and concentrate recovery rate 75.28% were achieved in one roughing.

[0039] Example 3

[0040] The invention discloses a collector for low-temperature reverse flotation of iron ore. The weight proportion of raw materials is as follows: 30 parts of synthetic fatty acid (average molecular weight 290), 12 parts of isopropanol, 3 parts of butyl acetate and 18 parts of 20% sodium hydroxide solution.

[0041] Preparation of low-temperature collector for iron ore in this example: ① At 50°C, add synthetic fatty acid, isopropanol and butyl acetate in a stirring barrel in sequence and stir to mix evenly. ② Raise the temperature to 90°C, drop 15% sodium hydroxide solution, stir and mix for 1 hour, and the preparation of low-temperature collector 3# is completed.

[0042] How to use collector 3#:

[0043] The prepared collector 3# was used for rough separation of red magnetic mixed iron ore with a TFe grade of 49.1%. The flotation process is as follows: Figure 1As shown, under the conditions of NaOH dosage 850g / t, starch dosage 900g / t, CaO dosage 300g / t, collector 3# dosage 650g / t, and flotation temperature 15°C, the flotation indicators of concentrate yield 54.15%, concentrate grade 68.18%, and concentrate recovery rate 75.49% were achieved in one roughing.

[0044] Comparative Example

[0045] A comparative collector was used, and the fatty acids in the collector were compared according to the same effective content. The flotation conditions were the same as those in Example 2. The effects of the collectors are compared in Table 1:

[0046] Table 1 Comparison of the effects of various collectors

[0047]

[0048]

Claims

1. A collector for low temperature reverse flotation of iron ore, characterized in that: The method is obtained by reacting fatty acids, alcohols, esters, inorganic bases and water as raw materials, wherein the raw materials are composed of the following mass percentages: 30%-80% fatty acids, 10%-30% alcohols, 3%-10% esters, 3%-10% inorganic bases, and the remainder is water, and the molar ratio of the inorganic base to the fatty acid is 0.5-1:1; The fatty acid is at least one of C13-C18 unsaturated straight-chain or branched-chain fatty acids, with an iodine value of 130-140 and a freezing point of -15-8°C; The alcohol is at least one of C2-C10 straight-chain or branched fatty alcohols; The ester is at least one of methyl benzoate, dimethyl phthalate, methyl acetate, ethyl acetate and butyl acetate.

2. The iron ore low temperature reverse flotation collector according to claim 1, characterized in that: The inorganic base is sodium hydroxide or potassium hydroxide.

3. The iron ore low temperature reverse flotation collector according to claim 1, characterized in that: The fatty acid is vegetable oleic acid, animal oleic acid or synthetic fatty acid.

4. The iron ore low temperature reverse flotation collector according to claim 1, characterized in that: The alcohol is at least one of ethanol, isopropanol, n-propanol, ethylene glycol, diethylene glycol, pentanol, hexanol and octanol.

5. A method for preparing the iron ore low temperature reverse flotation collector according to claim 1, characterized in that: The steps include: 1) At a certain temperature, the fatty acids, alcohols and esters are fully mixed according to the proportions; 2) The mixture is heated, and then an inorganic alkali solution with a mass concentration of 5% to 20% is added according to a proportion, stirred and saponified to obtain a collector.

6. The method for preparing the iron ore low temperature reverse flotation collector according to claim 5, characterized in that: The saponification temperature is 70-100° C., and the heat preservation time is 30-90 minutes.

7. The method for preparing the iron ore low temperature reverse flotation collector according to claim 5, characterized in that: The stirring is performed by mechanical stirring, and the stirring speed is controlled at 800 to 3000 rpm.

8. A method for using the iron ore low temperature reverse flotation collector according to claim 1, characterized in that: In the reverse flotation operation of iron ore, the amount of collector used is 500-1000g / t and the reverse flotation temperature is 15-20℃.

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