Quartz Surface Research Articles

Sodium citrate-sodium hydroxide synergy on remediating asphaltene-contaminated solids

Asphaltenes are the heaviest and surface-active polyaromatic compounds in crude oil. Their precipitation and deposition on sand surfaces switch the wettability of sand from water-wet to oil-wet, which is harmful to the oil recovery process. In this study, we demonstrate the synergistic effect between sodium hydroxide (NaOH) and sodium citrate (Na3Cit) on remediating asphaltene-contaminated silica from both experimental and molecular dynamics (MD) simulation perspectives. Asphaltene desorption efficiency increased from 39 % (Na3Cit only) to 84 % (NaOH + Na3Cit), attributed to better remediation of natural silica wettability and reduced silica-asphaltene adhesion with the co-addition chemicals. Fundamental insights for NaOH-Na3Cit synergy were revealed by MD simulation. The bonding between an asphaltene model compound (C5Pe) and the quartz (101) surface became thermodynamically less favorable when both NaOH and Na3Cit were present in the system, forcing the C5Pe molecules to move away from the surface. In summary, we highlight the NaOH-Na3Cit synergy in promoting the asphaltene detachment from silica surfaces, which has important implications in oil recovery and soil remediation applications.

Layer formation on quartz bed particles during fast pyrolysis of grass

Commercial fast pyrolysis technologies use bed materials, normally natural sand mainly consisting of quartz, acting as circulating heat carrier materials. Nowadays, the commercial conversion of biomass into fast pyrolysis bio-oil (FPBO) is still using ash-lean woody residues as a feedstock since the application of more abundant and possibly cheaper ash-rich agricultural biomass is currently at a significantly lower technology readiness level (TRL). To promote FPBO production from ash-rich biomass, the ash-related issues during the operation process need to be further studied. In the present investigation, the characteristics and formation process of layers formed on quartz bed particles, collected from a bench-scale fast pyrolysis unit based on the rotating cone technology, were studied. Two grass residues, representative of typical Si-K-rich agricultural biomass fuels, were used as feedstocks. Quartz bed particles at different sampling times from startup with fresh bed particles were collected. Scanning Electron Microscopy/Energy-Dispersive Spectroscopy (SEM/EDS) was employed to characterize the layer properties. Bed particle layers exhibited an uneven and discontinuous distribution on the quartz surface. This distribution over bed particles, as well as layer thickness, increased with the operational time. The dominating elements contained in layers were Si, K, Ca, and Cl (excluding O), which resembled that of individual bed ash particles found in the bed samples. In addition, the interpretation of the results was supported by thermodynamic equilibrium calculations. The findings suggest that the process of layer formation was governed by the direct adhesion of non-melted bed ash particles during the fast pyrolysis of grass.

Study on Selective Adsorption Behavior and Mechanism of Quartz and Magnesite with a New Biodegradable Collector

Research on the efficient flotation desilication of low-grade magnesite is of great significance for the sustainable development of magnesium resources. Traditional collectors usually have some disadvantages, such as poor selectivity, severe environmental pollution, and weak water solubility. To strengthen the desilication flotation process of magnesite ore, the biodegradable surfactant, cocamidopropyl amine oxide (CPAO), was first utilized as the collector for the separation of the magnesite and quartz. The selective adsorption behavior and mechanism of the quartz and magnesite with the CPAO as the collector were studied through the micro-flotation experiments of the single mineral and the artificially mixed mineral, contact angle and atomic force microscopy (AFM) measurements, fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. The flotation results indicated that the CPAO showed good selectivity and could effectively separate magnesite and quartz. When the concentration of the CPAO was 10.0 mg/L in the natural pulp pH (about 7.2), the concentrates with 97.67% MgO recovery and 45.62% MgO grade were obtained. The contact angle and AFM measurements indicated that the CPAO could selectively adsorb on the quartz surface rather than the magnesite surface to improve the interface difference between them, especially its surface hydrophobicity. The results of the FTIR and XPS analyses indicated that the CPAO is selectively adsorbed on the surface of the quartz, mainly through electrostatic interaction and hydrogen bonding. In conclusion, the CPAO had good selectivity and great potential as an effective collector in the reverse flotation desilication progress of magnesite.

Nanoscale Investigation into Dynamics of Thin Liquid Films during Bouncing and Attachment of Rising Air Bubbles on Hydrophilic and Hydrophobic Surfaces.

Investigations on bouncing and attachment of free-rising air bubbles on hydrophobic surfaces have been limited to side-view, high-speed photography of the bubble-plate attachment process. In this work, an investigation of the dynamics as well as stability of thin liquid films (TLFs) between free-rising air bubbles and quartz surfaces was performed using a newly developed multiple-wavelength synchronized reflection interferometry microscopy (SRIM) technique. The effect of surface hydrophobicity on both the stability and critical rupture thickness of TLFs was investigated. Results showed that the TLF ruptured at a critical rupture thickness of 100-1000 nm or beyond during bubble's impact on hydrophobic quartz surfaces. The critical rupture thicknesses varied depending on the surface hydrophobicity as well as surface asperity. A higher surface hydrophobicity, in general, contributed to a higher critical rupture thickness. In addition, the effect of n-octanol on the stability of the TLFs was investigated. Results showed that film stability increased with increasing the concentration of n-octanol, which was accompanied by a significant decrease in the critical rupture thickness. The present result illustrates, for the first time, the dynamics of TLFs on hydrophobic surfaces under a dynamic condition compared with previous studies under a quasi-equilibrium condition. The information revealed from the present work has a significant implication to many industrial applications, including froth flotation and other biological and semiconductor applications.

Regular Arrays of Rod-Shaped Molecular Photoswitches: Synthesis, Preparation, Characterization, and Selective Photoswitching within Mono- and Bilayer Systems.

We assembled photoresponsive mono- and bilayer systems with well-defined properties from rod-shaped molecules equipped with different photoswitches. Using properly chosen chromophores (diarylethene-based switch and unidirectional light-driven molecular motor), we then selectively targeted layers made of the same types of photoswitches using appropriate monochromatic light. UV-vis analysis confirmed smooth and unrestricted photoisomerization. To achieve this, we synthesized a new class of triptycene-based molecular pedestals adept at forming sturdy Langmuir-Blodgett films on a water-air interface. The films were smoothly transferred to gold and quartz surfaces. Repeated deposition afforded bilayer systems: one layer containing diarylethene-based photoswitches and the other a unidirectional light-driven molecular motor. Structural analysis of both mono- and bilayer systems revealed the molecules to be tilted with carboxylic functions pointing to the surface. At least two different polymorphs differing in monolayer thickness and tilt angle (~40° and ~60°) were identified on the gold surface.

FIXATION OF THE OPTICAL FIBER IN THE CONNECTOR USING HYDROGEL

A method of fastening optical fiber in a quartz connector with a sodium polysilicate hydrogel obtained in a cylindrical gap between the connector and the fiber due to the alkaline decomposition of quartz surfaces of parts was developed. The conditions of thermal decomposition of the hydrogel are determined and it is shown that the decomposition of the hydrogel with the formation of a cellular structure is possible at temperatures below the temperature of thermal decomposition of the polymer coating of the fiber. The conditions for obtaining and thermal properties of the hydrogel are determined. Conclusions are drawn about the suitability of the proposed method for fixing optical fiber in a quartz connector.

Quantitative competitive adsorption characteristics of sodium humate and dodecylamine on hematite and quartz surfaces

Competitive adsorption behavior of reagents is of great significance for efficient flotation separation of minerals. Motivated by the surface complex adsorption, surface complexation model (SCM) is an effective approach for quantitative characterization of reagents adsorption behavior. In this study, sodium humate (SH) adsorption and mixed SH and dodecylamine (DDA) competitive adsorption mechanisms onto hematite and quartz were quantitatively described and predicted using SCM. The model simulation suggested that there are two binding forms (monodentate and bidentate) between the groups on SH and the hematite sites and one (monodentate) with the quartz sites. The adsorption equilibrium constants (logK) of SH were calculated, which are 10.15, 23.34 (for hematite) and 10.41 (for quartz), respectively. In addition, the fitting results indicate that SH is adsorbed on the hematite surface mainly through the bidentate ≡Fe2-R(COO)2 site. Furthermore, the successful prediction of adsorption and surface potential at pH system were performed to verify the reliability of the model. Quantitative analysis of mixed SH and DDA interactions with mineral surfaces will elucidate and predict the reagents competitive adsorption behavior, which can also provide reliable data and parameters for surface complexation databases for surface complexation. Meanwhile, this finding provides valuable insights for the flotation of minerals, which enables their selective separation efficiency to be modulated and optimized.

Observation of a volatile astatine hydroxide species in online gas-adsorption thermochromatography experiments

During recent online gas-phase experiments with the transactinide elements copernicium (Cn, Z = 112) and flerovium (Fl, Z = 114), the transport of a volatile astatine species was observed. Comprehensive Monte Carlo simulations of the deposition pattern of 211At on the given quartz, selenium, and gold chromatographic surfaces were carried out, and the corresponding adsorption enthalpies were estimated. Based on the astatine speciation from previous model experiments, the compound observed in this work was ascribed to AtOH/HAtO. The herein presented results assist in paving the way toward a future chemical characterization of tennessine (Ts, Z = 117) with similar gas adsorption chromatography techniques.

Insights into the influence of calcium ions on the adsorption behavior of sodium oleate and its response to flotation of quartz: FT-IR, XPS and AMF studies

Assiduous efforts on the high-efficiency flotation of quartz with calcium ion activation have been ongoing, while there is a lack of understanding of its potential mechanism. In this research, insights into the influence of calcium ions on the adsorption behavior of sodium oleate and its response to flotation of quartz were systematically investigated. Micro-flotation experimental results show that addition order of calcium ions influences the quartz flotation. Ca2+/NaOL complexes exhibit higher flotation recovery of quartz (92.18 %) under the recommended conditions. The Zeta potential and Fourier transform infrared spectroscopy results indicate that the adsorption of NaOL onto bare quartz surfaces is extremely difficult, and the addition of Ca2+ promotes the adsorption of NaOL. X-ray photoelectron spectroscopy analysis results confirm that Ca2+/NaOL complexes reinforce the adsorption of NaOL and Ca2+ onto quartz surface by the formation of -Si-O-Ca-OOCR, and the Ca-OOCR content in the total Ca reaches 62.61 %. The adsorption amount results further illustrate that the adsorption amount of Ca2+ and NaOL increase to 18.56 × 10−2 mg/g and 40.83 × 10−2 mg/g, respectively. Additionally, starch slightly decrease the adsorption amount of Ca2+ on quartz surfaces. Atomic force microscope analysis reveal that Ca2+/NaOL components promote the formation of Ca-OOCR colloid precipitates and the transportation of the precipitates to the quartz surface. The main adsorption of Ca-OOCR colloid precipitates contributes to the enveloped bulge image. Notably, the Ca-OOCR colloid precipitates adsorption mechanism exerts more important role in the adsorption of sodium oleate and calcium ion species, as well as its response to flotation of quartz.

Effects of Hydrogen Bonds between Ethoxylated Alcohols and Sodium Oleate on Collecting Performance in Flotation of Quartz.

Hydrogen bonds play an important role in the interaction between surfactants. In this study, the effect of three different ethoxylated alcohols (OP-10, NP-10, AEO-9) on the collecting behavior of sodium oleate (NaOL) in the flotation of quartz was investigated. To explore the mechanism, the hydrogen bond between ethoxylated alcohols and NaOL was analyzed using molecular dynamics (MD) simulation. The results showed that ethoxylated alcohols promoted the collecting performance of NaOL and reduced the dosage of the activator CaO and the collector NaOL in the flotation of quartz. The Zeta potential measurement illustrated that ethoxylated alcohols promoted the adsorption of OL- on the activated quartz surface and the degree of promotion was in the order of OP-10 > NP-10 > AEO-9. The MD simulation results showed that a hydrogen bond presented between ethoxylated alcohols and OL-. Due to the hydrogen bond between the ethoxylated alcohols and OL-, the attraction force between OL- and the quartz surface increased with the addition of ethoxylated alcohols in the order of OP-10 > NP-10 > AEO-9 based on the MD simulation results. As the result, the addition of ethoxylated alcohols increased the adsorption density of OL- on the activated quartz surface, which explained the promotion of the collecting performance of OL- in the flotation of quartz.

Investigation into the Adsorption Mechanism of a Novel Collector Cetyl Trimethyl Ammonium Chloride on the Surface of Hematite and Quartz

In this research, a novel collector cetyl trimethyl ammonium chloride (CTAC) was used to separate hematite from quartz via reverse flotation for the first time. Micro-flotation tests showed that CTAC had a strong ability to selectively collect quartz and that a separation of hematite from quartz could be accomplished with a concentration of 0.00263 mmol/L CTAC. Zeta-potential measurements indicated that the positive CTAC+ species could selectively increase the surface potential of quartz, but that it had rather a weak effect on the hematite. X-ray photoelectron spectroscopy (XPS) detection indicated that CTAC had a stronger binding affinity to oxygen sites on the surface of quartz than on hematite, resulting in a large amount of CTAC being predominantly adsorbed onto quartz. This was supported by the atomic concentration of C1s and N1s of quartz after CTAC treatments were 4.25 and 2.84 times higher than hematite, respectively.

Quantification of Particle Filtration Using a Quartz Crystal Microbalance Embedded in a Microfluidic Channel.

To quantify colloidal filtration, a quartz crystal microbalance (QCM) with a silicon dioxide surface is embedded on the inner surface of a microfluidic channel to monitor the real-time particle deposition. Potassium chloride solution with micrometer-size polystyrene particles simulating bacterial strains flows down the channel. In the presence of intrinsic Derjaguin-Landau-Verwey-Overbeek (DLVO) intersurface forces, particles are trapped by the quartz surfaces, and the increased mass shifts the QCM resonance frequency. The method provides an alternative way to measure filtration efficiency in an optically opaque channel and its dependence on the ionic concentration.

Understanding the Behavior of Sodium Polyacrylate in Suspensions of Silica and Monovalent Salts.

This study investigated the interaction of monovalent cations with different sizes on quartz surfaces and the rheological impact that this causes in concentrated suspensions when subjected to the action of a rheological modifier, in this case, sodium polyacrylate (NaPA). Yield stress was determined using a rheometer with a vane-in-cup configuration to establish the relationship between shear stress and strain. Experiments were carried out in LiCl, NaCl, KCl, and CsCl solutions. The results show that the yield stress increases following the order Li < Na < K < Cs in the absence of PAA. However, the addition of NaPA significantly reduced the yield stress in all cases. This reduction was more noticeable in the LiCl and NaCl solutions than in the KCl and CsCl solutions, suggesting a more pronounced effect of PA in maker salts. We conducted molecular dynamics simulations to understand how PA interacts with dissolved salts on the quartz surface. Our results showed that Li had the highest adsorption, followed by Na, K, and Cs. As the salt concentration increased, so did the adsorption. We validated these simulation results with rheological experiments, which helped us understand the observed differences. The molecular interactions indicate that, in the lithium system, cationic bridges and the synergy between hydrogen bridges and hydrophobic bridges predominate mainly. This tendency decreases as the type of cation is changed due to the decrease in the electrical density of the cation in the following order: Li < Na < K < Cs. This reduces bridging with the quartz surface and, therefore, directly impacts the system's rheological properties.

Atomic insight into the activation mechanism of feldspar by sodium oleate in flotation separation of quartz and feldspar: XPS, AFM, and molecular dynamics

ABSTRACT As we all know, sodium oleate (NaOL) is usually used as a collector for oxidized minerals, but in this study, it is used as an activator for feldspar to separate from quartz. Therefore, the adsorption mechanism, topography, and configurations of NaOL on the quartz and feldspar surface were investigated using X-ray photoelectron spectroscopy, atomic force microscope, and molecular dynamics simulation at the atomic level. The results revealed that NaOL preferably interacted with the Al atoms on the feldspar surface mostly in the form of chemical adsorption and made the feldspar surface blurry and rough, so NaOL could activate feldspar and enhance its flotability. However, NaOL hardly reacts or is easily desorbed from the quartz surface. Thus, the adsorption differences of NaOL between the quartz and feldspar surfaces contributed to realize the effective separation of quartz and feldspar.

Coordination reaction triggered xanthan gum and Fe(III) self-assembly and adsorption on hematite surface for quartz-hematite flotation separation

The cation reverse flotation is a widely used method in improving the grade of iron ore concentrate, but hematite depressant is the key. In this work, the flotation behavior of hematite and quartz using the complex of Fe(III) and xanthan gum (Fe(III)-XG) as depressant was investigated via micro-flotation tests. The results show that Fe(III)-XG showed excellent separation efficiency for hematite from quartz using dodecylamine (DDA) as collector. The adsorption capacity and water contact angle analysis indicate that the adsorption of Fe(III)-XG onto hematite hinders the adsorption of DDA onto hematite surface, and the adsorption quantity of Fe(III)-XG on quartz surface is lower than on hematite surface. Further, XRD, FTIR and XPS analyses were performed to detect the functional part and adsorption mechanism of Fe(III)-XG. The results indicate that the coordination of Fe(III) with –COOH and –OH in xanthan gum (XG) could form Fe(III)-XG complex which is beneficial to adsorption onto mineral surface selectively. The weak adsorption of Fe(III)-XG onto quartz surface by sites of Si-OH could not hinder the electrostatic adsorption of positively charged DDA while the pre-adsorption of Fe(III)-XG on the hematite surface through selective chemical action hinders the adsorption of DDA. The model of flotation separation of hematite from quartz system with Fe(III)-XG and DDA was drawn.

Characterization of the effects of wettability and pore pressure on the interfacial behavior of CO2 interacting with oil-water two-phase on pore walls

To date, research studies on film-like residual oil have mainly focused on reservoirs in the late stage of water flooding development. However, there have been relatively few studies on film-like residual oil on pore walls after gas flooding. In this study, a molecular dynamics simulation method was used to investigate the behavior characteristics of fluid-fluid and fluid-solid interfaces and the exploitation potential of film-like remaining oil in water-wet, mixed-wet and oil-wet systems under different pore pressures after CO2 flooding. The results indicated that in the oil-in-water system, the cohesive energy density (CED) of the water films was much greater than that of the CO2 and decane components, and the CED of water films in the water-wet systems was slightly greater than the CED of water films in the mixed-wet systems. Regardless of the water-wet or mixed-wet systems, Einter(CO2−decane) was the strongest between the components. Therefore, CO2 molecules could easily enter the oil films and divide the oil phase into clusters of different sizes. The interfacial tension at the CO2 + decane/H2O and H2O/SiO2 interfaces in both the water-wet and mixed-wet systems decreased with increasing pressure. Under the same pressure, the degree of decrease in interfacial tension at the CO2 + decane/H2O interface in the mixed-wet systems was smaller than that in the water-wet systems. The degree of decrease in interfacial tension at the H2O/SiO2 interfaces in the mixed-wet systems was generally greater than that in the water-wet systems. In the water-in-oil system, because the water films isolated the oil films from the CO2 molecules, the interaction energy between the CO2 molecules and oil phase was weak, so the oil films remained on the quartz surfaces. Due to the existence of the hydrogen bond network inside the water phase, the morphological changes in water films were also small when the CO2 molecules interacted with the water phase. At the CO2/H2O interfaces, under the same pressure, the resistance of CO2 molecules to pass through the water films in the oil-wet systems was greater than that in the mixed-wet systems, and the CO2 molecules in the mixed-wet systems were more likely to enter into the water films. The interfacial tension reduction at the interfaces in the mixed-wet systems was smaller than that in the oil-wet systems. At the H2O/decane interfaces, the power of CO2 molecules breaking through the oil-water interfaces and entering into the oil phase in both the mixed-wet and oil-wet systems was basically equal under the same pressure. The interfacial tension reduction at the interfaces in the mixed-wet systems was almost equal to that of the oil-wet systems. At the decane/SiO2 interfaces, the CED of the oil films in the oil-wet systems was greater than that in the oil-wet systems under the same pressures, and the Einter(CO2−SiO2) in the mixed-wet systems was greater than the Einter(CO2−SiO2) in the oil-wet systems, indicating that CO2 molecules were more easily adsorbed on the quartz surfaces in the mixed-wet systems, and the interfacial tension reduction at the interfaces in the mixed-wet systems was greater than that of the oil-wet systems. The interfacial tension at the CO2/H2O, H2O/decane and decane/SiO2 interfaces in both the mixed-wet and oil-wet systems decreased with increasing pressure. The research results provide a reference for understanding the fluid-fluid and fluid-solid interface behaviors and the exploitation potential of film-like residual oil during CO2 gas flooding.

Synergistic mechanism of adsorption-diffusion at quartz-water interface for the dewatering of waste slurry using APAM flocculant: Insights from molecular dynamics simulation

In this study, molecular dynamics simulations were performed to investigate the flocculation and soil-water separation mechanism of anionic polyacrylamide (APAM) flocculant. Results show that the adsorption behavior of APAM on quartz particles in the quartz-water interface is the basis for flocculation occurrence, and the adsorption ability improves with the increases in APAM dosage. APAM molecules compete with the water molecular layer and are directly adsorbed on the surface of quartz through hydrogen bonds, while most APAM structures are indirectly adsorbed on the quartz surface through van der Walls forces. The diffusion behavior is the key to determining effective flocculation. The apparent chain self-entanglement of APAM molecules hinders the diffusion of APAM on the water surface as the APAM dosage increases, corresponding to a decrease in the diffusion coefficient. This phenomenon results in APAM molecules failing to collide with enough quartz particles on the water surface. The bridging action generated by the balance between adsorption-diffusion behavior is the key to the flocculation and dewatering effect. Additionally, flocculation treatment tests of waste slurry using APAM with different dosages were conducted, and the size of the flocs at different APAM concentrations was examined by SEM, further confirming the existence of the optimal amount of APAM.

Reducing CO2 emissions and improving oil recovery through silica aerogel for heavy oil thermal production

Heavy oil reserves comprise more than 60% of global crude oil resources, and thermal oil recovery techniques, especially steam injection, are widely utilized for extracting heavy oil. However, these thermal production processes are characterized by high energy consumption and carbon emissions, which pose significant challenges in reducing CO2 emissions. In response to these challenges, this study presents a novel approach that combines silica aerogel with CO2-assisted thermal recovery technology. Our findings demonstrate that the incorporation of aerogel nanoparticles enhances the adsorption capacity of CO2 in the aqueous phase. The adsorption behavior of CO2 in silica aerogel aligns with the Langmuir model. When silica aerogel nanoparticles are employed in steam flooding, a notable improvement is observed in both oil recovery and CO2 sequestration rate. Molecular dynamics simulations reveal that the porous structure of aerogel enables the adsorption of light saturates molecules from crude oil, promoting their diffusion into the aqueous phase and ultimately enhancing oil recovery. The steam condensation experiments clearly demonstrate that the presence of aerogel and CO2 exerts a substantial influence on the condensation heat transfer of steam, resulting in a reduction in the condensation heat transfer rate between the steam and the cooling wall. Additionally, molecular dynamics simulations reveal that silica aerogel nanoparticles exhibit an affinity for adsorbing onto hydrophobic quartz surfaces, forming an insulating layer between steam and quartz, thereby facilitating CO2 sequestration. The introduction of silica aerogel nanoparticles expands the swept volume of steam heat. This study provides valuable insights into the underlying mechanisms responsible for improved CO2 sequestration and increased oil recovery through the implementation of silica aerogel nanoparticles, offering fresh perspectives on heavy oil recovery.

Insights into the desilication mechanism of goethite by anionic reverse flotation from hydroxyl role

This paper mainly investigates the role of hydroxyl on the desilication of goethite by anionic reverse flotation. Accordingly, micro-flotation experiments suggested that the activation effect of Ca(II) on quartz was obviously better than that of goethite in the high alkaline sodium oleate (OL) system.. Furthermore, the Zeta potential also confirmed that the selectivity of Ca(II) ions on quartz surface was better than that on goethite surface. Solution chemical analysis revealed that the dominant species of activator Ca(II) and collector OL were Ca2+ and OL−, respectively. Fourier transform infrared (FT-IR) spectroscopy suggested that OL− could not form an effective adsorption on mineral surfaces in the absence of Ca2+, while OL - had a strong chemisorption in the presence of Ca2+. Density functional theory (DFT) calculations demonstrated that the successful floating of quartz involves three surface modifications, namely the surface hydroxylation, the adsorption of Ca2+ on the hydroxylated surface, and the adsorption of OL− on the Ca2+-activated surface. In this process, hydroxylation is the prerequisite for the subsequent adsorption of Ca2+ and OL−. Besides, the selective adsorption of sodium humate (SHM) causes the flocculation and inhibition of goethite, which also plays a key role in the desilication of goethite.

Proposing a novel factor influencing flotation collector abilities to collect minerals by comparing two cationic collectors N,N-bis(2-hydroxy-3-chloropropyl) dodecylamine and dodecylamine

Dodecylamine (DDA) is a commonly used cationic collector in the reverse flotation of apatite and quartz but has poor selectivity. To improve the selectivity of DDA, two 2-hydroxy-3-chloropropyl groups are introduced to the structure of DDA to create a novel cationic collector N,N-bis(2-hydroxy-3-chloropropyl) dodecylamine (BHCPDA). Flotation experiments demonstrate that BHCPDA has better selectivity than DDA. The findings from zeta potential experiments and X-ray photoelectron spectroscopy analysis consistently indicate that BHCPDA exhibits a greater adsorption amount on quartz surface compared to apatite. This observation explains its heightened ability for collecting quartz in the flotation relative to apatite. However, both the methods also reveal that BHCPDA displays a higher adsorption amount on apatite surface than DDA, whereas DDA demonstrates a greater efficiency in collecting apatite. This implies that the efficacies of flotation collectors in collecting minerals are not solely dependent on their adsorption amounts on the mineral surfaces. First-principles calculations indicate that BHCPDA and DDA adopt distinct adsorption configurations on quartz surface, leading to a reduced collecting ability of BHCPDA for quartz. The integration of the flotation experiments with the various test methods leads to the conclusion that the adsorption configurations of collectors on mineral surfaces significantly influence their abilities to collect the minerals.