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Article

Interaction Forces between Diaspore and Kaolinite in NaOL Solution Probed by EDLVO Theory and AFM Analysis

by
Yankun Wu
1,2,
Shichong Yang
1,2,
Wencui Chai
1,3,* and
Yijun Cao
1,2,*
1
Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou 450001, China
2
School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
3
Henan Province Industrial Technology Research Institution of Resources and Materials, Zhengzhou University, Zhengzhou 450001, China
*
Authors to whom correspondence should be addressed.
Minerals 2022, 12(9), 1123; https://doi.org/10.3390/min12091123
Submission received: 10 August 2022 / Revised: 30 August 2022 / Accepted: 1 September 2022 / Published: 3 September 2022
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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Abstract

:
Molecular force plays an important role in the interaction between collector and minerals, which directly reflects the intrinsic reason for the selectivity and collection of the collector to minerals. In this work, the interaction forces between sodium oleate (NaOL) and minerals (kaolinite and diaspore) were directly characterized by atomic force microscopy (AFM) combined with EDLVO theory. The results show that after interacting with NaOL, the zeta potentials of kaolinite and diaspore were more negative, and the hydrophobicity of minerals increased. EDLVO calculation results indicate that electrostatic repulsion dominated the interaction forces between mineral particles, and the van der Waals interaction energy, electrostatic interaction energy, and hydrophobic interaction energy increased after NaOL treatment. AFM measurements show that the NaOL collector increased the attraction force of diaspore-diaspore and kaolinite-kaolinite particles, and the increase in attraction force for diaspore-diaspore particles was larger than in kaolinite particles, which was consistent with the EDLVO results. The adhesion force between the NaOL collector and the diaspore surface was larger than in kaolinite, confirming the fact that NaOL had better collection and selectivity for diaspore than kaolinite. This work improves understanding of the interaction mechanisms between NaOL collector, diaspore, and kaolinite minerals.

1. Introduction

Sodium oleate (NaOL), as a commonly used flotation collector of oxidized ore, is often used as the collector of diaspore in the flotation desilication of bauxite [1,2,3,4,5,6,7,8,9]. In order to explore the interaction mechanisms between NaOL and diaspore in the flotation process, various testing techniques have been used, including zeta potential, contact angle, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and so on [10,11,12,13]. The zeta potential and contact angle testing found that NaOL changed the surface electrical property and wettability of minerals, thus improving the separation of diaspore from silicon-containing minerals. In addition, XPS and FTIR measurements revealed the interaction between NaOL and diaspore was mainly through the carboxyl group of NaOL combined with Al sites on the diaspore surface. In recent years, density functional theory (DFT) was also used to declare the interaction between NaOL and aluminum-silicate minerals [13]. All the above research methods describing the interaction mechanism between collector and diaspore are from the point of interface solution chemistry, while rare studies are from the point of microscopic molecular force to elucidate the NaOL-diaspore interactions, such as the extended DLVO theory and atomic force microscope (AFM) technique, especially AFM measurement [14,15,16].
The classical DLVO theory is not only used to explain the colloid stability, but also to illustrate the molecular interaction energy between agents and fine mineral particles, or fine mineral particles themselves in the flotation process [17,18,19,20,21]. DLVO theory indicates that the interaction between colloidal mineral particles is controlled by both van der Waals force and electrical double layer force. The extended DLVO (EDLVO) theory found that repulsive hydration forces, hydrophobic attraction, magnetic attraction, and steric repulsion are also sometimes present between the mineral particles [22,23]. Yu et al. [16] used the DLVO theory to study the effects of pH and divalent cations on the interaction between montmorillonite and fine coal. It was found that pH and divalent cations could affect the dispersion and condensation between montmorillonite and fine coal by changing electrical double layer force, and further affect the flotation performance. Besides, it is reported that the electrostatic interaction between diaspore particles decreased when the diaspore surface adsorbed calcium and magnesium ions [21]. It has been proved that with the increasing adsorption amount of calcium ions onto the illite surface, the van der Waals attraction between illite particles increased, and the electrostatic force and polar repulsion weaken, which was conducive to the flocculation and precipitation of illite particles [24].
With the development of technology, the AFM technique has made great progress in recent years, which makes it possible to directly measure molecular forces. Many researchers have used atomic force microscopes to measure the forces between collector and mineral particles in the flotation process [25,26,27,28]. The adsorption of flotation agents on the mineral surfaces also could be characterized by AFM. By observing the high-resolution surface topography of mineral samples, the adsorption of reagents on the mineral surfaces could be visually understood. It is reported that after the treatment of the collector, the changes in scheelite surface topography were measured by AFM, revealing the adsorption of the collector on the scheelite surface and the flotation collecting mechanism [29,30]. Through measuring the interaction forces between particles, particles and agents, and particles and bubbles, the interaction mechanisms of flotation reagents in the flotation separation process were revealed [31,32,33,34,35].
In this work, the interaction mechanism of NaOL in the flotation separation of diaspore from kaolinite was investigated from the point of microscopic molecular force using AFM measurement and EDLVO theory. The surface properties of diaspore and kaolinite before and after NaOL treatment were also characterized through contact angle and zeta potential testings, which is fundamental to the study of molecular forces using the EDLVO theory.

2. Materials and Methods

2.1. Minerals and Reagents

The single minerals (diaspora and kaolinite) are from Henan province in China. The minerals were ground and screened into three particle sizes (−38 μm, +38 μm ~ −74 μm, +74 μm), and the −38 μm samples were used to prepare a colloidal probe of AFM technology. The typical chemical and mineralogical compositions of single minerals were analyzed by X-ray diffraction (XRD) and X-ray fluorescence (XRF) and shown in Figure 1 and Table 1, respectively. The XRD patterns in Figure 1 show that the diaspore sample was composed of diaspore and a small quantity of anatase. The kaolinite sample mainly contains kaolinite and a small quantity of quartz. As seen in Table 1, the main components of diaspore are Al2O3 and SiO2, accounting for 76.57% and 1.57%, respectively. Moreover, the main components of kaolinite are Al2O3 and SiO2, accounting for 37.96% and 47.19%, respectively. The results indicate that the purity of the diaspore and kaolinite samples is more than 90%.
Hydrochloric acid (HCl) and sodium hydroxide (NaOH) used as pH regulators were purchased from Sigma Aldrich. Sodium oleate and trimethoxysilane used as collector and silylating reagents, respectively, were bought from Mclean Industrial Corporation, China. Unless specifically noted, all the reagents used in this study were of analytical grade, and deionized water (DIW) was used for all tests.

2.2. Zeta Potential Testing

Zeta potentials of diaspore and kaolinite particles before and after being treated with NaOL were tested by Zetasizer Nano ZSP (Malvern Panalytical, UK); 30 mg of mineral samples (−5 μm) each time were first added into 35 mL 1 × 10−3 mol/L of KCl electrolyte solution or 60 mg/L NaOL solutions, and mixed and adjusted the pH value with NaOH or HCl. The mixture was stirred for 10 min and then stood for 30 min. The suspension of the pulp was finally collected for the measurement of zeta potential [36]. Each test was repeated three times, and the averaged values were reported.

2.3. Contact Angle Measurement

The contact angles of diaspore and kaolinite particles before and after being treated with NaOL were measured by a contact angle measuring instrument (Zhongchen JC2000D3W, China); 2 g of the full-size mineral samples were dispersed in 35 mL of deionized water or a 60 mg/L NaOL solution; the pH value was adjusted with NaOH or HCl. The pulp was stirred for 30 min, filtered, and dried to obtain the treated mineral particles. The treated mineral particles were pressed into a dense plane to be used for contact angle measurement [36].

2.4. EDLVO Theory

In EDLVO theory, the total interaction energy (VT, J) between minerals particles consisted of van der Waals interaction energy ( V W , J), electrical double layer interaction energy ( V E , J), and hydrophobic interaction energy ( V H , J) [37,38,39,40]. The formula of the total interaction energy is shown in Equation (1). All the formulas are based on the interaction energy model between the spherical mineral particle and the mineral plate.
V T = V W + V E + V H

2.4.1. Van der Waals Interaction Energy

The van der Waals interaction energy between the spherical mineral particle and the mineral plate was calculated by Equation (2).
V w = − A 12 R H
where R is the radius (m) of the mineral particle, H is the separation distance (m) between the sphere-particle and the mineral plate, and A is the Hamaker constant (J) between the sphere-particle and the mineral plate.
The Hamaker constant is calculated by Equations (3) and (4).
A 131 = ( A 11 1 / 2 − A 33 1 / 2 ) 2
A 232 = ( A 22 1 / 2 − A 33 1 / 2 ) 2
where A131 and A232 are the Hamaker constants for diaspore and kaolinite particles in water, respectively. A11, A22, and A33 represent the Hamaker constants (J) for diaspore particles, kaolinite particles, and water in the vacuum, respectively. The Hamaker constants of diaspore, kaolinite and water are approximately 15.20 × 10−20 J, 10.97 × 10−20 J, 3.70 × 10−20 J, respectively.

2.4.2. Electrostatic Interaction Energy

The electrostatic interaction energy is caused by the charge on the mineral surface in the solution system and was calculated by Equation (5).
V E R = 4 π ε a k ψ 1 ψ 2 exp ( − k H ) 1 + exp ( − k H )
where ψ 1 and ψ 2 are the surface potential (V) of minerals approximated by the Zeta potential [19,20,21,41,42], ε a is the dielectric constant of water 6.95 × 10−10 C2/(J·m), and k − 1 is Debye length (m).
Debye length was calculated by Equation (6) under the condition of 1:1 electrolyte.
k − 1 = 1 1.039 × 10 8 ( c z 2 ) 1 / 2
where c (mol/L) is solution concentration, and z is the number of charges in the solution.

2.4.3. Hydrophobic Interaction Energy

The hydrophobic interaction energy is a special attraction between hydrophobic mineral surfaces and was calculated by Equation (7).
V H = 2 π V H 0 h 0 R e x p ( − H h 0 )
where h 0 is the attenuation length (m) generally ranging from 1 to 10 nm, and V H 0 is the hydrophobic force constant (J/m2).
The hydrophobic force constant was calculated by Equation (8).
V H 0 = − 0.00251 2 π e x p ( θ 100 ) − 1 e − 1
where θ is the contact angle of minerals (°).

2.5. AFM Measurements

2.5.1. Preparation of Colloid Particle Probe

The colloidal probe of mineral particles was prepared by attaching diaspore and kaolinite particles onto the tipless cantilever using epoxy resin adhesive, and the main steps are shown in Figure 2. The tipless probe with an elastic coefficient of 1.0 N/m was successively washed with chromatographically pure anhydrous ethanol and deionized water three to five times and then blown dry with N2. A small number of mineral particles (10~30 μm) were dispersed in 100 mL of anhydrous ethanol, then transferred to the clean glass sheet, and dried under vacuum at 60 °C for 30 min. The mineral particles were finally attached to the tipless probe by an AFM contact mode [31,32].

2.5.2. Preparation of Collector Probe

The preparation of the collector probe mainly included the silanization of the probe and adsorption of the collector NaOL, as shown in Figure 3. The probe with an elastic coefficient of 1.0 N/m was firstly cleaned according to the above method. The probe was then silanized with trimethoxysilane by vapor deposition method under a N2 atmosphere for 4 h, cleaned with anhydrous ethanol to remove excess trimethoxysilane, and blown dry by N2. Finally, the probe was immersed in a 60 mg/L NaOL solution for 5 h, and the needed collector probe was obtained after being cleaned with anhydrous ethanol and deionized water in turn [43,44].

2.5.3. Interaction Force Measurement

The interaction forces between the particles and particle-collector were measured by AFM Nano Waizd 4 (JPK, Germany, Figure 4). The measurement steps are as follows: The mineral colloid probe, or collector probe, was first installed onto the holder. The mineral substrate was fixed in a culture dish, and 95 mL of deionized water or 60 mg/L NaOL with pH 9 was slowly added to the culture dish. After adjusting the laser and setting the parameters, the force measurement was carried out by contact mode. Each test was repeated 100 times, and all test data were analyzed by JPK Data Processing 4.

3. Results and Discussion

3.1. Surface Properties of Diaspore and Kaolinite

3.1.1. Zeta Potential Analysis

The surface charge property of minerals is an important factor affecting intermolecular forces and was analyzed by zeta potential testing. The zeta potentials of diaspore and kaolinite particles with or without treated 60 mg/L NaOL at different pH are shown in Figure 5. As seen in Figure 5, the isoelectric point (IEP) of diaspore and kaolinite was pH 4.60 and pH 3.65, respectively, in accordance with the reported literature [10,36,45,46]. The zeta potentials of diaspore and kaolinite were more negative with increasing pH. After treatment of NaOL, the zeta potentials of diaspore and kaolinite were more negative, indicating that the negatively charged NaOL had been absorbed on the two minerals’ surfaces [10]. It should be pointed out that after NaOL treatment, the zeta potential of the diaspore shift in alkaline conditions was larger than that for kaolinite, stating that more NaOL was adsorbed onto the diaspore surface, and that it had a stronger interaction with diaspore than kaolinite.

3.1.2. Wettability Analysis

Surface wettability is another important factor affecting intermolecular forces and was analyzed by contact angle testing [47]. The contact angles of diaspore and kaolinite surfaces with or without treated 60 mg/L NaOL at different pHs are shown in Figure 6. As shown in Figure 6, before treatment with the NaOL collector, the contact angles of the diaspore were no more than 30° and slightly affected by pH. After treatment with the NaOL collector, the contact angles of the diaspore were greatly increased, indicating NaOL largely increased the hydrophobicity of the diaspore surface. It is worth noting that the contact angle increased with pH increasing from 3 to 9 and reached the maximum value of 90° at pH 9. The trend was the same as the flotation results reported in our previous work [36]. Figure 6 also shows that before treatment with the NaOL collector, the contact angles of kaolinite were no more than 25° and slightly increased with pH increasing from 3 to 9. After treatment with a NaOL collector, the contact angles of the kaolinite became larger and increased with pH, increasing from 3 to 9, reaching the maximum value of 39.2° at pH 9. However, the effect of NaOL on the contact angle of kaolinite was smaller than that of diaspore, probably because less collector was adsorbed onto the kaolinite surface. From the contact angle results, it could be known that the NaOL collector increased the wettability difference between diaspore and kaolinite, thus improving the flotation separation of diaspore from kaolinite [10].

3.2. Interaction Energy between Mineral Particles

Since the better flotation separation of diaspore from kaolinite was achieved at pH 9, the interaction energies between particles in deionized water and NaOL solution at pH 9 were calculated by EDLVO theory, including van der Waals interaction energy, electrostatic interaction energy, hydrophobic interaction energy, and total interaction energy.

3.2.1. Van der Waals Interaction Energy

The van der Waals interaction energy of diaspore-diaspore particles and kaolinite-kaolinite particles before and after being treated with the NaOL collector was shown in Figure 7. Before being treated with the NaOL collector, the van der Waals interaction energy for diaspore-diaspore particles (VW-diaspore) was larger than that of kaolinite-kaolinite particles (VW-kaolinite). After being treated with the NaOL collector, VW-diaspore and VW-kaolinite increased, since the adsorption of NaOL increased the particle radius.

3.2.2. Electrostatic Interaction Energy

The electrostatic interaction energy of diaspore-diaspore particles and kaolinite-kaolinite particles before and after being treated with the NaOL collector was shown in Figure 8. Before being treated with the NaOL collector, the electrostatic interaction energy for kaolinite-kaolinite particles (VE-kaolinite) was larger than that of diaspore-diaspore particles (VE-diaspore), and both of them were positive, indicating there were electrostatic repulsive forces. After being treated with the NaOL collector, both VE-diaspore and VE-kaolinite increased, and VE-diaspore was larger than VE-kaolinite. The results declare that NaOL largely increased the electrostatic repulsive forces of particles, which was beneficial to particle dispersion and further conducive to flotation recovery.

3.2.3. Hydrophobic Interaction Energy

The hydrophobic interaction energy of diaspore-diaspore particles and kaolinite-kaolinite particles before and after being treated with the NaOL collector was shown in Figure 9. Before being treated with the NaOL collector, the hydrophobic interaction energy for kaolinite-kaolinite particles (VH-kaolinite) was larger than that of diaspore-diaspore particles (VH-diaspore), and both of them were negative, indicating there were attractive forces. After being treated with the NaOL collector, both VH-diaspore and VH-kaolinite increased, and VE-diaspore was larger than VE-kaolinite. The results indicate that NaOL largely increased the hydrophobic attraction of diaspore particles, which was beneficial to the diaspore particles’ adhesion to the bubbles.

3.2.4. Total Interaction Energy

The total interaction energy of diaspore-diaspore particles and kaolinite-kaolinite particles before and after being treated with the NaOL collector was shown in Figure 10. Before being treated with the NaOL collector, the total interaction energy for kaolinite-kaolinite particles (VT-kaolinite) was larger than that of diaspore-diaspore particles (VT-diaspore), and both of them were positive, indicating there were repulsive forces. After being treated with the NaOL collector, both VT-diaspore and VT-kaolinite increased. Although VT-kaolinite was still larger than VT-diaspore, the values were already very close. The results indicate that NaOL largely increased the repulsive forces of particles, which was beneficial to particle dispersion.

3.3. Adhesion Force between Mineral Particles

In order to directly elucidate the effects of NaOL collector on the interactions between diaspore-diaspore and kaolinite-kaolinite particles, the interaction forces between mineral particles in water and NaOL solution at pH 9 were measured by AFM. The results are shown in Figure 11 and Figure 12.
Figure 11 shows the representative force curves between the diaspore-terminated probe and the diaspore surface. In the approach process, the jump-in phenomena existed in water and NaOL solution at pH 9, indicating the existence of an attractive force. It was also found that the adhesion force in NaOL solution was much larger than in water, which could be attributed to the fact that the NaOL collector increased the van der Waals force and the hydrophobic force. It should be pointed out that no repulsive force was detected, this may be due to the pH regulator and collector solution shielding the electrostatic force [48,49]. The adhesion force is defined as the maximum attractive force experienced by the probe during the retraction process [50,51]. In the retraction process, the adhesion force between the diaspore-terminated probe and diaspore surface in water at pH 9 was 1.21 nN, while the adhesion forces in NaOL solution at pH 9 was 25.13 nN, indicating the NaOL collector increased the interaction between diaspore particles.
Figure 12 shows the typical force curves between the kaolinite-terminated probe and the kaolinite surface. From the approaching force curves, it can be seen that the jump-out and jump-in phenomena existed in water and NaOL solution at pH 9, indicating the existence of a repulsive force first and then an attractive force. The repulsive force was an electrostatic force, while the attractive forces were the van der Waals force and the hydrophobic force. It was also found that the adhesion force in NaOL solution was much larger than in water. As seen from the retraction force curves, the adhesion force between the kaolinite-terminated probe and the kaolinite surface in water at pH 9 was 5.05 nN, while the adhesion forces in NaOL solution at pH 9 was 17.10 nN. The increase in adhesion forces between diaspore-terminated and diaspore surface by NaOL collector was larger than that involving kaolinite, probably because there were more NaOL adsorbed on the diaspore surface and increased the attractive forces between diaspore particles.

3.4. Adhesion Force between Collector and Mineral Particles

In order to further verify the interaction between the NaOL collector and diaspore/kaolinite particles, the interaction forces between the NaOL probe and diaspore/kaolinite surfaces in water pH 9 were measured, as shown in Figure 13. In the approach process, the jump-in phenomena existed between the NaOL probe and the diaspore/kaolinite surfaces, indicating the existence of an attractive force. There is also a jump-out phenomenon that existed between the NaOL probe and diaspore surface, stating the existence of a repulsive force. Even so, it was also found that the adhesion force between the NaOL probe and diaspore surface was much larger than that between the NaOL probe and kaolinite surface, which was the intrinsic reason why more NaOL collector was adsorbed on the diaspore surface than on the kaolinite surface. In the retraction process, the adhesion force between the NaOL probe and the diaspore surface was 17.03 nN, while the adhesion force between the NaOL probe and the kaolinite surface was 3.51 nN.

4. Conclusions

Atomic force microscopy (AFM) was applied to directly characterize the interaction forces between mineral-mineral (kaolinite and diaspore) and NaOL collector-minerals; the EDLVO theory was also used to analyze the van der Waals interaction energy, electrostatic interaction energy, and hydrophobic interaction energy between mineral particles with or without the NaOL collector at pH 9. EDLVO calculations show that the NaOL collector could increase the van der Waals interaction energy, electrostatic interaction energy, and hydrophobic interaction energy between kaolinite/diaspore particles. Furthermore, the dominant interaction was electrostatic repulsion, which is conducive to particle dispersion. AFM measurement results show the adhesion force between the NaOL collector and the diaspore surface was 17.03 nN, larger than that involving kaolinite, which was 3.51 nN; this was the intrinsic reason why more NaOL collector was adsorbed on the diaspore surface than the kaolinite surface. The NaOL collector vastly increased the adhesion forces between diaspore particles and kaolinite particles, including van der Waals force and hydrophobic force, consistent with the results of the EDLVO calculation. Due to the shielding of the electrostatic force by a high concentration of pH regulator and collector solution, no or small repulsive force was detected. AFM and EDLVO were excellent theoretical and experimental methods to investigate the interaction mechanisms between the collector and minerals at the molecular level.

Author Contributions

Conceptualization, Y.W. and W.C.; methodology, Y.W. and W.C.; validation, Y.W. and S.Y.; formal analysis, Y.W. and S.Y.; investigation, Y.W.; resources, Y.W., S.Y. and W.C.; data curation, Y.W.; writing—original draft preparation, Y.W.; writing—review and editing, W.C. and Y.C.; visualization, Y.W. and W.C.; supervision, W.C. and Y.C.; project administration, W.C.; funding acquisition, W.C. and Y.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Natural Science Foundation of China (Nos. 52004249 and U1704252) and National Key Research and Development Program (2020YFC1908801).

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

The authors are grateful to Zhengzhou University for providing a good research platform. Reviewers’ insightful comments and valuable suggestions are greatly appreciated.

Conflicts of Interest

The authors declare no conflict of interest.

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Minerals 12 01123 g001 550
Figure 1. XRD patterns of diaspore (a) and kaolinite (b).
Figure 1. XRD patterns of diaspore (a) and kaolinite (b).
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Figure 2. Schematic diagram of the colloid probe preparation.
Figure 2. Schematic diagram of the colloid probe preparation.
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Figure 3. Schematic diagram of the collector probe preparation.
Figure 3. Schematic diagram of the collector probe preparation.
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Figure 4. Photograph of AMF (a) and schematic diagram of force testing (b).
Figure 4. Photograph of AMF (a) and schematic diagram of force testing (b).
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Figure 5. Zeta potentials of diaspore (a) and kaolinite (b) before and after interaction with NaOL.
Figure 5. Zeta potentials of diaspore (a) and kaolinite (b) before and after interaction with NaOL.
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Figure 6. Contact angles of diaspore and kaolinite before and after interaction with NaOL.
Figure 6. Contact angles of diaspore and kaolinite before and after interaction with NaOL.
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Figure 7. Van der Waals interaction energy between mineral particles in different solution.
Figure 7. Van der Waals interaction energy between mineral particles in different solution.
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Figure 8. Electrical double layer interaction energy between particles in different solutions.
Figure 8. Electrical double layer interaction energy between particles in different solutions.
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Figure 9. Hydrophobic interaction energy between particles in different solutions.
Figure 9. Hydrophobic interaction energy between particles in different solutions.
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Figure 10. Total interaction energy between particles in different solutions.
Figure 10. Total interaction energy between particles in different solutions.
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Figure 11. Interaction forces between diaspore and diaspore in different solutions: (a) approach curves; (b) retraction curves.
Figure 11. Interaction forces between diaspore and diaspore in different solutions: (a) approach curves; (b) retraction curves.
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Figure 12. Interaction forces between kaolinite and kaolinite in different solutions: (a) approach curves; (b) retraction curves.
Figure 12. Interaction forces between kaolinite and kaolinite in different solutions: (a) approach curves; (b) retraction curves.
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Figure 13. Interaction forces between NaOL collector and mineral particles: (a) approach curves, (b) retraction curves.
Figure 13. Interaction forces between NaOL collector and mineral particles: (a) approach curves, (b) retraction curves.
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Table
Table 1. Chemical composition analysis results of diaspore and kaolinite.
Table 1. Chemical composition analysis results of diaspore and kaolinite.
MineralsAl2O3 1SiO2 1TiO2 1Fe2O3K2ONa2OCaOMgOLOI
Diaspore76.571.572.941.090.480.0410.0670.06814.43
Kaolinite37.9647.190.240.380.020.0740.160.1413.84
1 Based on chemical analysis.
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Wu, Y.; Yang, S.; Chai, W.; Cao, Y. Interaction Forces between Diaspore and Kaolinite in NaOL Solution Probed by EDLVO Theory and AFM Analysis. Minerals 2022, 12, 1123. https://doi.org/10.3390/min12091123

AMA Style

Wu Y, Yang S, Chai W, Cao Y. Interaction Forces between Diaspore and Kaolinite in NaOL Solution Probed by EDLVO Theory and AFM Analysis. Minerals. 2022; 12(9):1123. https://doi.org/10.3390/min12091123

Chicago/Turabian Style

Wu, Yankun, Shichong Yang, Wencui Chai, and Yijun Cao. 2022. "Interaction Forces between Diaspore and Kaolinite in NaOL Solution Probed by EDLVO Theory and AFM Analysis" Minerals 12, no. 9: 1123. https://doi.org/10.3390/min12091123

APA Style

Wu, Y., Yang, S., Chai, W., & Cao, Y. (2022). Interaction Forces between Diaspore and Kaolinite in NaOL Solution Probed by EDLVO Theory and AFM Analysis. Minerals, 12(9), 1123. https://doi.org/10.3390/min12091123

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