Nanometer alumina armored pickering emulsion collector and preparation method and application thereof
By forming rigid oil droplet armor using nano-alumina armored Pickering emulsion collector, the problems of collector instability and gangue entrainment in low-rank coal flotation are solved, achieving efficient flotation of fine-grained low-rank coal with a yield increase of 74.64%.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIUPANSHUI NORMAL UNIV
- Filing Date
- 2026-06-04
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, poor collector adhesion and the tendency of conventional emulsified collectors to become unstable under shear and cause gangue entrainment during the flotation of low-rank coal result in low separation efficiency and make it difficult to effectively improve the flotation clean coal yield of fine-grained low-rank coal.
The use of nano-alumina armored Pickering emulsion collectors, through the synergistic effect of nano-alumina particles and cationic surfactants, forms irreversible rigid oil droplet armor, eliminating the interfacial electrostatic repulsion energy barrier and improving the flotation clean coal yield of fine coal.
It significantly improved the flotation clean coal yield of fine-grained low-rank coal from 41.68% to 74.64%, and maintained oil droplet stability under high shear conditions, enhancing the binding efficiency of bubbles and particles.
Smart Images
Figure CN122377641A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coal washing and mineral processing technology, and more specifically relates to a nano-alumina armored Pickering emulsion collector, its preparation method, and its application. Background Technology
[0002] Low-rank coal (including lignite and long-flame coal) accounts for approximately half of global coal reserves and is an important strategic energy source. However, low-rank coal has a low degree of coalification, a well-developed macroporous structure, and an abundance of oxygen-containing functional groups (such as hydroxyl and carboxyl groups) on its surface. With the widespread adoption of large-scale mechanized coal mining and crushing processes, the proportion of fine-grained coal slime (<0.045 mm) is continuously increasing. To address this issue, emulsified collectors (such as using Span 80 and Tween 80 to emulsify kerosene) are commonly used in industry to reduce oil droplet size and increase the probability of oil-coal contact.
[0003] The numerous oxygen-containing sites on the surface of low-rank coal strongly coordinate with water molecules through hydrogen bonds, forming a robust hydration film that exhibits extremely poor natural hydrophobicity. In traditional water-based flotation, the oil droplets (50-100 μm) produced by conventional non-polar oil collectors (such as kerosene and diesel) are much larger than ultrafine coal particles, resulting in a severe size mismatch and an extremely low collision probability. Traditional surfactant emulsification methods face insurmountable challenges in dynamic solution chemistry: free surfactant molecules not only competitively adsorb at oil-water and coal-water interfaces, leading to hydrophobic gangue minerals, but this competitive migration also strips the emulsifier from the oil droplets, weakening the collector's anchoring on the coal surface; simultaneously, excessive surfactant leads to overly stable foam, severely entraining hydrophilic gangue slime and reducing separation efficiency. Pickering emulsions based on organic macromolecules are constrained by weak reversible non-covalent forces, and under the intense hydrodynamic shear of the flotation machine, the organic particle film is prone to deformation or partial desorption.
[0004] Therefore, how to provide an ultra-stable nano-alumina armored Pickering emulsion collector to fundamentally optimize interfacial thermodynamics and solve the problems of slow flotation kinetics, high reagent consumption, and poor selectivity of fine-grained low-rank coal has become an urgent problem to be solved in this field. Summary of the Invention
[0005] To address the problems of poor collector adhesion and the instability of conventional emulsified collectors under shear, which can easily lead to gangue entrainment in the existing low-rank coal flotation process, this invention provides a nano-alumina armored Pickering emulsion collector, its preparation method, and its application. This collector can form an irreversible rigid oil droplet armor, accurately target fine coal particles, and significantly improve the flotation clean coal yield of fine low-rank coal particles while eliminating the interfacial electrostatic repulsion energy barrier.
[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a nano-alumina armored Pickering emulsion collector, the raw materials of which include: kerosene, emulsifier Tween 80, cetyltrimethylammonium bromide (CTAB) and nano-alumina (Al2O3).
[0007] Furthermore, the ratio of kerosene, emulsifier Tween 80, cetyltrimethylammonium bromide (CTAB), and nano-alumina (Al2O3) is 50 g: 15 g: 10 g. -6 mol:(1×10 -5 ~3×10 -5 ) mol.
[0008] Furthermore, the hexadecyltrimethylammonium bromide is added in the form of an aqueous solution at a concentration of 10. -5 mol / L.
[0009] Furthermore, the nano-alumina is γ-phase nano-alumina with a particle size of 1-20 nm, preferably 10 nm.
[0010] The nano-alumina armored Pickering emulsion collector provided by this invention is a Pickering emulsion collector with the synergistic effect of nanoparticles and cationic surfactants. This collector can form an irreversible rigid oil droplet armor, accurately target fine coal particles, and significantly improve the flotation clean coal yield of fine low-rank coal while eliminating the interfacial electrostatic repulsion energy barrier.
[0011] The second technical solution of this invention provides a method for preparing the above-mentioned nano-alumina armored Pickering emulsion collector, the steps of which include: Kerosene, emulsifier Tween 80, and nano-alumina are mixed evenly to obtain a premix. The premix was added to an aqueous solution of hexadecyltrimethylammonium bromide and homogenized and emulsified to obtain the nano-alumina armored Pickering emulsion collector.
[0012] Furthermore, the homogenization emulsification process is carried out at a rotation speed of 8000-12000 rpm (preferably 10000 rpm) for a time of 20-30 min (preferably 25 min).
[0013] The third technical solution of the present invention provides an application of the above-mentioned nano-alumina armored Pickering emulsion collector in coal mine flotation.
[0014] The fourth technical solution of the present invention provides a flotation method for low-rank coal, wherein the collector used in the method is the above-mentioned nano-alumina armored Pickering emulsion collector.
[0015] Furthermore, the amount of collector used in the flotation process is 0-12 kg / t, and the amount is not zero.
[0016] The present invention discloses the following technical effects: The nano-alumina armored Pickering emulsion collector provided by this invention utilizes nano-alumina particles that adhere almost irreversibly to the oil-water interface with a desorption free energy as high as 400.3 kT, forming a dense and rigid armored layer around the kerosene droplets. This effectively prevents Ostwald ripening and droplet aggregation under high shear conditions, generating deep submicron oil droplets with a large specific surface area. After adding this emulsion, the Zeta potential on the coal surface shifts sharply from -18.40 mV to +10.30 mV, completely eliminating the electrostatic repulsion barrier and transforming the interaction between bubbles and particles into a strong attraction. Based on the extended DLVO theory, the physical presence of nano-alumina increases local steric hindrance, extending the wetting film drainage time from 88 ms to 94-95 ms, significantly enhancing the binding efficiency between bubbles and particles. Considering the above mechanisms, compared to the highest yield of 41.68% in deionized water, using this composite emulsion can significantly increase the clean coal yield of fine-grained low-rank coal to 74.64%. Attached Figure Description
[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram comparing the application of a traditional emulsifying collector (Comparative Example 1, left figure) and a nano-alumina armored Pickering emulsion collector (Example 1, right figure). Detailed Implementation
[0018] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0019] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0020] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0021] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0022] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0023] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.
[0024] Unless otherwise specified, room temperature and normal temperature in the specific embodiments of this invention refer to 20-30℃.
[0025] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.
[0026] Example 1 The preparation steps of the nano-alumina armored Pickering emulsion collector include: S1. Raw material preparation: 3×10 -5 mol γ-phase nano-alumina (10 nm), 50 g kerosene, 15 g Tween 80 and 100 mL of 10 -5 A mol / L aqueous solution of CTAB.
[0027] S2. Mix kerosene, emulsifier Tween 80 and γ-phase nano-alumina evenly to obtain a premix; S3. Add the premix to the CTAB aqueous solution and homogenize and emulsify at 10,000 rpm for 25 min. Adjust the final concentration of nano-alumina to 3 × 10⁻⁶. -5 mol / L, to obtain nano-alumina armored Pickering emulsion collector.
[0028] Example 2 The difference compared to Example 1 is that the raw material composition is as follows: 10 -5 mol γ-phase nano-alumina (10 nm), 50 g kerosene, 15 g Tween 80 and 100 mL of 10 - 5 A mol / L aqueous solution of CTAB.
[0029] Adjust the final concentration of nano-alumina to 10. -5 mol / L, to obtain nano-alumina armored Pickering emulsion collector.
[0030] Comparative Example 1 Traditional emulsified collectors: Mix 50 g of kerosene and 15 g of Tween 80, then add the mixture to 100 mL of aqueous solution and emulsify at 10,000 rpm for 25 min to obtain a conventional emulsifying collector (without nano-alumina).
[0031] Comparative Example 2 The difference from Example 1 is that the γ-phase nano-alumina was replaced with an equal amount of SiO2.
[0032] Comparative Example 3 The difference from Example 1 is that the γ-phase nano-alumina was replaced with an equal amount of TiO2.
[0033] Test case Figure 1 This is a schematic diagram comparing the application of a traditional emulsifying collector (Comparative Example 1, left figure) and a nano-alumina armored Pickering emulsion collector (Example 1, right figure).
[0034] The collectors prepared in the examples and comparative examples were used for the flotation treatment of low-rank coal, and the steps are as follows: Low-rank coal slime (particle size <0.50 mm) was prepared into a slurry with a concentration of 60 g / L and pre-stirred for 120 s. Collector (12 kg / t) was added, and the slurry was adjusted for 120 s. Then, 10 kg / t terpineol frother was added and mixed for 30 s. Aeration was carried out at 200 L / h, and foam was collected by skimming for 180 s. The flotation parameters are shown in Table 1. The control group consisted of raw coal subjected to flotation tests in a deionized water environment without any added collector.
[0035] Table 1 The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A nano-alumina armored Pickering emulsion collector, characterized in that, Raw materials include: Kerosene, emulsifier Tween 80, cetyltrimethylammonium bromide, and nano-alumina.
2. The nano-alumina armored Pickering emulsion collector as described in claim 1, characterized in that, The ratio of kerosene, emulsifier Tween 80, cetyltrimethylammonium bromide, and nano-alumina is 50 g:15 g:10 g. -6 mol: (1×10 -5 ~3×10 -5 ) mol.
3. The nano-alumina armored Pickering emulsion collector as described in claim 1, characterized in that, The hexadecyltrimethylammonium bromide was added in the form of an aqueous solution at a concentration of 10%. -5 mol / L.
4. The nano-alumina armored Pickering emulsion collector as described in claim 1, characterized in that, The nano-alumina is γ-phase nano-alumina with a particle size of 1-20 nm.
5. A method for preparing the nano-alumina armored Pickering emulsion collector according to any one of claims 1-4, characterized in that the step... include: Kerosene, emulsifier Tween 80, and nano-alumina are mixed evenly to obtain a premix. The premix was added to an aqueous solution of hexadecyltrimethylammonium bromide and homogenized and emulsified to obtain the nano-alumina armored Pickering emulsion collector.
6. The preparation method according to claim 5, characterized in that, The homogenization emulsification process is carried out at a speed of 8000-12000 rpm for 20-30 min.
7. The application of the nano-alumina armored Pickering emulsion collector according to any one of claims 1-4 in coal mine flotation.
8. A flotation method for low-rank coal, characterized in that, The collector used in the method is the nano-alumina armored Pickering emulsion collector as described in any one of claims 1-4.
9. The method as described in claim 8, characterized in that, The amount of collector used in the flotation process is 0-12 kg / t, and the amount is not zero.