Preparation method and application of magnetic nanoparticle flotation inhibitor

Abstract

The invention belongs to the technical field of iron ore flotation quality improvement and utilization, and relates to a preparation method and application of a magnetic nanoparticle flotation inhibitor. The preparation and application steps are as follows: (1) ultrasonically dispersing Fe3O4 magnetite nanoparticles in water, adding sodium citrate to the dispersion, and stirring for reaction for 0.5 to 2 hours; (2) taking xanthan gum powder and adding it to deionized water with a pH value of 6 to 10, maintaining a water bath constant temperature of 30°C, and stirring for reaction for more than 12 hours; (3) slowly adding the solution of step (2) to the nanoparticle dispersion of step (1), stirring for reaction at a constant temperature in a water bath, performing solid-liquid separation using a magnet, collecting black matter, and washing with water until the pH value is neutral to obtain a magnetic nanoparticle flotation inhibitor XG@Fe3O4; adjusting the pH value to 5 to 10; sequentially adding the above inhibitor and amine collector to the ore pulp and stirring for 3 minutes each, adding a frother and stirring for 1 minute, and obtaining a final qualified iron concentrate product through roughing and concentrating, significantly improving the selective adsorption and inhibitory effect of the agent on iron minerals, and improving the sorting index.

Description

Technical Field

[0001] The invention belongs to the technical field of iron ore flotation quality improvement and utilization, and specifically relates to a preparation method and application of a magnetic nanoparticle flotation inhibitor. Background Art

[0002] The quality characteristics of iron oxide ore, "poor, fine, and impure", are important factors restricting the efficient utilization of iron ore in my country. The grade of iron concentrate directly affects the improvement of blast furnace utilization coefficient and the efficiency and cost of ironmaking production. How to efficiently increase iron and reduce impurities is an important problem currently faced. In order to effectively utilize difficult-to-select hematite, a series of measures such as flash magnetization roasting-weak magnetic separation and deep reduction-magnetic separation technology have been used for hematite beneficiation and quality improvement, but the problem of difficult recovery of fine-grained embedded hematite has not been solved. Flotation technology is an effective method for treating fine-grained embedded difficult-to-select iron ore, especially the use of reverse flotation technology to produce high-quality iron concentrate has obvious advantages. Flotation reagents are the most important influencing factors for achieving iron ore reverse flotation to increase iron and reduce impurities. It is usually necessary to add a large amount of starch or its derivatives during the flotation process to inhibit iron minerals. Although starch inhibitors can effectively inhibit coarse-grained hematite, they have weak inhibitory effect and poor selectivity on fine-grained hematite. Therefore, finding iron mineral inhibitors with strong inhibitory effect and good selectivity is a hot topic in current research. The macromolecular substances formed by the polymerization of starch and industrial polysaccharides are also an important research direction for inhibitors. CN113926591A and CN114669401A respectively disclose a starch and industrial alginate polymerization inhibitor and a supramolecular inhibitor for reverse flotation of hematite. It is particularly important to point out that quartz and iron-containing silicates are the main gangue minerals in iron ore. Both iron-containing silicates and iron minerals have a large number of structural iron ions, and the surface properties are very different. It is difficult to expand the difference in adsorption selectivity on the surface of iron minerals and gangue minerals only from the perspective of inhibitor structure performance.

[0003] The biggest difference between iron minerals and other minerals is that they are magnetic. However, a large number of studies have only focused on the surface properties of minerals during flotation and the increase in the apparent particle size of fine-grained iron minerals by agglomeration of magnetic species, ignoring the effect of the magnetic properties of iron-containing minerals on the adsorption of inhibitors on their surfaces. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a magnetic nanoparticle flotation inhibitor and its application, so as to solve the problems of weak inhibitory force and poor selectivity of existing inhibitors.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A method for preparing a magnetic nanoparticle flotation inhibitor, the specific steps are as follows:

[0007] (1) Fe 3 O4 Magnetite nanoparticles were ultrasonically dispersed in water, sodium citrate was added to the dispersion to promote particle dispersion, and the reaction was stirred at a certain temperature for 0.5 to 2 h;

[0008] (2) Add xanthan gum powder to deionized water with a pH of 6 to 10, maintain a constant temperature of 30°C in a water bath, and stir at a constant speed of 300 r / min for more than 12 h;

[0009] (3) Slowly add the solution of step (2) into the nanoparticle dispersion of step (1), stir the reaction in a water bath at a constant temperature, separate the solid and liquid using a magnet, collect the black substance, and wash it with water until the pH is neutral. The obtained black substance is the magnetic nanoparticle flotation inhibitor XG@Fe 3 O 4 .

[0010] In the step (1), Fe 3 O 4 Magnetite nanoparticles are composed of Fe 2+ / Fe 3+ It is prepared by co-precipitation method, with a particle size of less than 100 nm, a dosage of 20-50 g / L, a mass concentration of sodium citrate solution of 1-5 g / L, and a reaction temperature of 10-40 °C.

[0011] In the step (2), the mass concentration of xanthan gum is 0.5-2 g / L, and a dilute HCl or NaOH solution is used as a pH regulator.

[0012] In the step (3), the volume ratio of the nanoparticle dispersion to the xanthan gum solution is 1:1 to 3:1, the xanthan gum droplet addition rate is 10 to 50 mL / min, and the reaction conditions are constant temperature stirring in a water bath at 60 °C and intermittent mechanical stirring at a speed of 200 to 600 r / min for 12 to 24 h.

[0013] The application of the magnetic nanoparticle flotation inhibitor is applied to the iron ore cationic reverse flotation process. The inhibitor must be fully dispersed by ultrasound before use. The specific steps are as follows:

[0014] The iron ore sample ground to monomer dissociation is adjusted into a slurry of appropriate concentration. The slurry concentration is determined according to the ore properties and process, and sodium hydroxide is added to adjust the pH. The above inhibitors and amine collectors are added to the slurry in turn and stirred for 3 minutes each. Finally, a frother is added and stirred for 1 minute to carry out flotation operations. After rough selection, the above inhibitors are added again for a concentration to obtain the final qualified iron concentrate product.

[0015] The pH is 5-10, and the dosage of the inhibitor is 50-200 mg / L.

[0016] During the flotation process, the reagent creates the necessary space and time conditions under long-range forces such as fluid transport force, electrostatic force, and van der Waals force, which is a prerequisite for its characteristic adsorption on the mineral surface. The key to improving the adsorption selectivity of flotation reagents on the mineral surface lies in regulating the long-range physical forces during the adsorption process between the reagent and the mineral.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The surface of magnetic nanoparticles is modified with hydrophilic xanthan gum, and the long-range magnetic attraction between the magnetic nanoparticles and the magnetic minerals is used to regulate the adsorption of hydrophilic xanthan gum on the surface of the magnetic minerals, thereby improving the weak adsorption inhibition force and poor selectivity of polyhydroxy inhibitors on the mineral surface. Compared with the traditional reverse flotation, the dosage of starch inhibitors is small, which not only increases the iron grade of the concentrate and improves the recovery rate, but also reduces the consumption and waste of food crops in iron ore reverse flotation operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The scanning electron microscope (a), magnetic curve (b) and infrared spectrum (c) of the magnetic nanoparticle flotation inhibitor of the present invention;

[0020] Figure 2 It is a process flow chart in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments. Example 1

[0022] The magnetically separated iron concentrate with a total iron content of 68.87% was mixed with quartz with a purity of 99.4% at a ratio of 2:1. The total iron content of the mixed ore was 45.98%; the grinding fineness was -0.074mm, accounting for 80%. The following examples were carried out using this mixed ore as a sample. Figure 2 As shown, the specific implementation steps are as follows:

[0023] Take a Fe 2+ / Fe 3+ Nano-Fe prepared by co-precipitation method 3 O 45.0 g of particles were added to 100 mL of water and ultrasonically dispersed for 10 min; 0.2 g of sodium citrate was added to the ultrasonic dispersion and stirred for 1 h in a 30°C water bath to obtain a nanoparticle dispersion. 0.1 g of xanthan gum powder was added to 100 mL of deionized water with a pH of 6, the water bath was kept at a constant temperature of 30°C, and the reaction was stirred at a constant speed of 300 r / min for 24 h to obtain a xanthan gum solution. 100 mL of xanthan gum solution was added to 100 mL of nanoparticle dispersion at a drop rate of 10 mL / min, stirred in a constant temperature water bath at 60 °C for 18 h, and mechanically stirred at a speed of 200 r / min for 15 min every 1 h to obtain a magnetic nanoparticle flotation inhibitor, such as Figure 1 As shown, Figure 1 As can be seen from (a) and (b), the diameter of the magnetic nanoparticle inhibitor is about 200 nm, the surface is uniform and smooth without cracks; there is no hysteresis phenomenon, the superparamagnetism of the magnetic particles is maintained, and it can be used as a magnetic adsorbent for magnetic minerals. Figure 1 (c) It shows that the inhibitor is rich in hydrophilic groups such as hydroxyl and carboxyl groups.

[0024] The mixed ore was adjusted to a pulp with an ore mass concentration of 35%, and the following substances were added to the pulp in sequence: pH adjuster sodium hydroxide (adjust the pulp pH to 8.0), magnetic nanoparticle flotation inhibitor 80 mg / L, collector dodecylamine 100 g / t, frother No. 2 oil 30 g / t, and flotation roughing was carried out after 3 minutes of pulping, and the roughing time was 3 minutes; the inhibitor was added for a primary concentration, the concentration inhibitor dosage was 30 mg / L, and the concentration time was 3 minutes to obtain the final flotation concentrate product.

[0025] The implementation results of this example are as follows: the iron grade of the concentrate finally obtained by the method of the present invention is 69.2%, and the iron recovery rate is 88.7%. Compared with the original conventional starch inhibitor, the iron grade of the concentrate using this method is increased by 2.4 percentage points, and the iron recovery rate is increased by 6.5 percentage points. Example 2

[0026] The processing raw materials and methods are basically the same as those in Example 1, except that: when preparing the magnetic nanoparticle flotation inhibitor, the concentration of the nanoparticle dispersion is 40 g / L, the mass concentration of the sodium citrate solution is 5 g / L; the concentration of the xanthan gum solution is 2 g / L, and the pH value during preparation is 10; the volume ratio of the nanoparticle dispersion to the xanthan gum solution is 3:1, and the xanthan gum drop rate is 50 mL / min. The suitable dosages of the prepared magnetic nanoparticle flotation inhibitor in the roughing and concentrating of the flotation process are 120 and 50 mg / L, respectively. The iron grade of the concentrate finally obtained by the method of the present invention is 70.3%, and the iron recovery rate is 86.8%. Example 3

[0027] The processing raw materials and methods are basically the same as those in Example 1, except that: when preparing the magnetic nanoparticle flotation inhibitor, the concentration of the nanoparticle dispersion is 50 g / L, the mass concentration of the sodium citrate solution is 1 g / L; the concentration of the xanthan gum solution is 0.5 g / L, and the pH during preparation is 7; the volume ratio of the nanoparticle dispersion to the xanthan gum solution is 2:1, the xanthan gum drop rate is 20 mL / min, the reaction is stirred in a 60 ° C constant temperature water bath for 24 h, and mechanically stirred at a speed of 500 r / min for 3 min every 0.5 h. The suitable dosage of the prepared magnetic nanoparticle flotation inhibitor in the roughing and concentrating of the flotation process is 90 and 50 mg / L, respectively. The iron grade of the concentrate finally obtained by the method of the present invention is 68.2%, and the iron recovery rate is 90.8%. Example 4

[0028] The processing raw materials and methods are basically the same as those in Example 1, except that: when preparing the magnetic nanoparticle flotation inhibitor, the concentration of the nanoparticle dispersion is 20 g / L, the mass concentration of the sodium citrate solution is 1 g / L, and the reaction is stirred for 1 h in a 40°C water bath to obtain a nanoparticle dispersion; the concentration of the xanthan gum solution is 1.5 g / L, and the pH value during preparation is 9; the volume ratio of the nanoparticle dispersion to the xanthan gum solution is 1.5:1, and the xanthan gum drop rate is 30 mL / min. The suitable dosages of the prepared magnetic nanoparticle flotation inhibitor in the roughing and concentrating of the flotation process are 60 and 60 mg / L, respectively. The iron grade of the concentrate finally obtained by the method of the present invention is 66.7%, and the iron recovery rate is 91.2%.

Claims

1. A method for preparing a magnetic nanoparticle flotation inhibitor, characterized in that: The specific steps are as follows: (1) Ultrasonic dispersion of Fe3O4 magnetite nanoparticles in water, adding sodium citrate to the dispersion, and stirring the reaction at a certain temperature for 0.5 to 2 h; (2) Add xanthan gum powder to deionized water with a pH of 6 to 10, maintain a constant temperature of 30°C in a water bath, and stir at a constant speed of 300 r / min for more than 12 h; (3) Slowly add the solution of step (2) into the nanoparticle dispersion of step (1), stir the reaction in a water bath at a constant temperature, separate the solid and liquid with a magnet, collect the black substance, and wash with water until the pH is neutral. The obtained black substance is the magnetic nanoparticle flotation inhibitor XG@Fe3O4.

2. The method for preparing a magnetic nanoparticle flotation inhibitor according to claim 1, characterized in that: In the step (1), the Fe3O4 magnetite nanoparticles are composed of Fe 2+ / Fe 3+ It is prepared by co-precipitation method, with a particle size of less than 100 nm, a dosage of 20-50 g / L, a mass concentration of sodium citrate solution of 1-5 g / L, and a reaction temperature of 10-40 °C.

3. The method for preparing a magnetic nanoparticle flotation inhibitor according to claim 1, characterized in that: In the step (2), the xanthan gum mass concentration is 0.5-2 g / L, and a dilute HCl or NaOH solution is used as a pH regulator.

4. A method for preparing a magnetic nanoparticle flotation inhibitor according to any one of claims 1 to 3, characterized in that: In the step (3), the volume ratio of the nanoparticle dispersion to the xanthan gum solution is 1:1 to 3:1, the xanthan gum droplet addition rate is 10 to 50 mL / min, and the reaction conditions are constant temperature stirring in a water bath at 60 °C and intermittent mechanical stirring at a speed of 200 to 600 r / min for 12 to 24 h.

5. Use of the magnetic nanoparticle flotation inhibitor prepared by the preparation method according to claim 1, characterized in that: Applied to the iron ore cationic reverse flotation process, the inhibitor must be fully dispersed by ultrasound before use.

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