Salicylhydroxamic Acid Adsorption Research Articles

Adsorption of salicyl hydroxamic acid and octyl hydroxamic acid mixture on the cassiterite minerals

Salicylhydroxamic acid (SHA) and octyl hydroxamic acid (OHA) are two commonly used hydroxamic acid-based collectors in fine cassiterite flotation. While some reports suggest that a mixture of OHA and SHA yields superior results compared to their individual use, there is a lack of experimental exploration and theoretical analysis. In this study, the flotation performance and the associated adsorption mechanism of SHA, OHA and their mixture on fine cassiterite particles was systematically investigated. The results demonstrate a synergistic effect between SHA and OHA in enhancing fine cassiterite flotation, with the most significant enhancement occurring at a 1:1 mass ratio under the natural pH conditions. This finding is corroborated by contact angle and zeta potential tests. When both SHA and OHA are present, SHA likely attaches to the cassiterite surface via chemisorption in the form of a five-membered chelate ring, while OHA adheres through physical adsorption, primarily establishing hydrogen bonds with oxygen sites on the cassiterite surface or with SHA molecules. The adsorption ratio of SHA to OHA onto cassiterite surfaces is approximately 69%: 31% when an equal mass of SHA and OHA interact with cassiterite under the natural pH condition.

Selective Adsorption of Sodium Silicate on the Surface of Bastnaesite and Fluorite in Salicylhydroxamic Acid System under Alkaline Conditions

During the flotation separation process of bastnaesite, it is difficult to separate bastnaesite from fluorite effectively. In this present study, sodium silicate (SS) can effectively improve the flotation separation effect of bastnaesite and fluorite in salicylhydroxamic acid (SHA) systemasa. Through relevant analyses, such as Zeta potential measurements, adsorption capacity tests, Fourier transform infrared (FTIR) spectroscopic analyses and X-ray photoelectron spectroscopy (XPS) tests, the selective suppressor of SS on fluorite was proven. At pH 10, the single mineral flotation results show that with the increase of SS dosage, the flotation recovery of fluorite rapidly decreases from 61.5% to 35.31%, while the flotation rate of bastnaesite is still high (recovery is 80.02%). Then, the experiment of artificial mixed ore proved that the flotation separation of fluorite and bastnaesite was effective under the appropriate dosage of inhibitor. The results of potentiodynamic measurement and an adsorption capacity test showed that the SiOOH3− structure of SS more easily reacted with fluorite, which further prevented the adsorption of SHA on the fluorite surface. FTIR test results and XPS analysis further showed that SS had a strong binding effect with the Ca site on the fluorite surface, but a weak binding effect with the Ce site on the bastnaesite surface. Consequently, SS can be used as an effective inhibitor in the flotation separation of fluorite and bastnaesite.

Enhanced adsorption of salicylhydroxamic acid on ilmenite surfaces modified by Fenton and its effect on floatability

This work reports a new method of using Fenton to oxidize and modify the ilmenite surface using salicylhydroxamic acid (SHA) as the collector. The activation mechanism of this process was studied by analyzing changes that occurred on the ilmenite surface. Micro-flotation showed that the maximum recovery of ilmenite after treatment with Fenton increased by 37% and attributed to the increase in the adsorbed SHA amount on the ilmenite surface. Zeta potential and XPS measurement data showed that Fenton promoted the conversion of Fe2+→Fe3+ on the ilmenite surface that enhanced SHA adsorption. After adding Fenton, the Fe-SHA complex (formed in the pulp) interacted with the O sites of ilmenite surfaces, and improved the ilmenite floatability. The infrared spectra of the ilmenite+Fenton+SHA system showed several intense bands that indicated enhanced SHA chemisorption on the ilmenite surface. Thus, ilmenite treatment with the Fenton promoted its surface reactivity caused SHA to bind with the ilmenite surface and enhanced the ilmenite floatability.

Effects of grinding media on the flotation performance of cassiterite

Grinding plays an important role in the beneficiation process. Different grinding media can determine the size distribution, shape, and even the surface properties of the produced material. However, comprehensive research related to the effect of grinding media on the flotation performance of cassiterite is lacking. In the current study, the effects on the flotability of the products obtained by grinding with ceramic and stainless steel media were investigated using micro-flotation, laser particle size distribution analysis, inductively coupled plasma optical emission spectroscopy (ICP-OES), chemical element analysis, zeta potential measurements, field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS), and X-ray photoelectron spectroscopy (XPS). The micro-flotation results demonstrate that the flotability of stainless steel ground cassiterite surpasses that of ceramic. The laser particle size distribution test reveals that the two grinding media do not have a strong impact on the particle size distribution. The ICP-OES and chemical element analysis results identify the higher iron content in the samples and pulp of stainless steel ground cassiterite as the principle influencing factor. The zeta potential analysis indicates that the dissolved iron ions absorbed on the cassiterite surface results in a positive shift of the mineral surface potential. This not only reduces electrostatic repulsion but also increases the active sites of salicylhydroxamic acid (SHA) chemisorption. FESEM-EDS results demonstrate the rougher surface and higher iron content of the stainless steel ground cassiterite compared to the ceramic ground cassiterite, thereby increasing the SHA adsorption. The stainless steel grinding cassiterite was observed to alter the chemical environment of Fe species on the cassiterite surface via XPS analysis, with Fe2+ exhibiting a stronger reactivity and stability towards SHA compared to Fe3+. Thus, the stainless steel media ground cassiterite demonstrates an improved flotability performance compared to the ceramic equivalent.

The activation mechanism of Fe(II) ion-modified cassiterite surface to promote salicylhydroxamic acid adsorption

This paper systematically analyzed the effects of Fe(II) ions on the cassiterite surface to promote the adsorption of salicylhydroxamic acid (SHA). The interaction behavior and mechanisms re investigated using micro-flotation experiments, adsorption experiments, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The micro-flotation tests revealed that the Fe(II) ions had a strong activation effect on the cassiterite, and the recovery reached the maximum at pH values of 7–8. The results of the adsorption experiment showed that the adsorption capacity of SHA on the mineral surface significantly improved after Fe (II) ion activation; this result was confirmed by the zeta potential test. In addition, the zeta potential results indicated that the positively charged Fe species absorbed on the cassiterite surface led to positive changes in the mineral surface potential and an increase in the number of active sites, thereby increasing the SHA adsorption. The XPS and FTIR results demonstrated that the Fe(II) ions activated the cassiterite through the interaction of terminal oxygen atoms with Fe species on the cassiterite surfaces, and redox reactions and displacement reactions occurred between Fe2+ and Sn4+. SHA was chemisorbed on the cassiterite surface, allowing the anions to react readily with the Fe species to form Fe-SHA complexes. Therefore, the Fe(II) ion-activated cassiterite surfaces enhanced the strength and stability of the SHA chemisorption. Based on the results, an adsorption model of the Fe(II) ion-activated cassiterite surface in the SHA system was established.

Enhancement of salicylhydroxamic acid adsorption by Pb(II) modified hemimorphite surfaces and its effect on floatability

Hemimorphite is an important zinc oxide mineral, but only a few studies have been conducted on the enhanced flotation recovery of hemimorphite with salicylhydroxamic acid (SHA) as the collector. In this study, the effect of Pb(II) on SHA adsorption on the hemimorphite surface with regard to its floatability was systematically studied. X-ray photoelectron spectroscopy (XPS) analysis showed that the Pb species could interact with O sites on the hemimorphite surface, thus forming ZnOPb and SiOPb complexes on the mineral surface and exhibiting strong reactivity toward SHA. Zeta potential measurements indicated that Pb2+ and Pb(OH)+ adsorbed onto the hemimorphite surfaces via physical and chemical adsorption within a pH range that was suitable for the flotation, further enhancing SHA adsorption on the activated mineral surface. Adsorption tests showed that more SHA adsorbed on the Pb-treated hemimorphite surface than on the untreated hemimorphite, and Pb-SHA complexes that were generated in the pulp solution could also adsorb on the surface of hemimorphite. Micro-flotation tests confirmed that the floatability of hemimorphite significantly increased after treatment with Pb(II) ions when SHA was used as the collector. Thus, this paper proposes a promising method of improving the flotation recovery of hemimorphite through via surface modification with Pb(II) ions.

Bastnaesite, Barite, and Calcite Flotation Behaviors with Salicylhydroxamic Acid as the Collector

The flotation of bastnaesite, as a major mineral source of rare earth elements, attracting much attention in the mineral processing field, is challenging owing to the natural flotability of calcium-bearing minerals. To promote the application of flotation, we systematically investigated the flotation behavior of bastnaesite, barite, and calcite, with salicylhydroxamic acid (SHA) as the collector through micro-flotation experiments, zeta-potential measurements, Fourier transform infrared (FT-IR) analyses, X-ray photoelectron spectroscopy (XPS) analyses, and solution chemistry analyses. Micro-flotation experiments confirm that the flotability of bastnaesite is high at pH 6.5–8.5, while calcite floats at pH 8.0–9.5, and barite has little flotation response. The results of FT-IR, XPS, and zeta-potential measurements indicate that there is chemical adsorption of SHA on the bastnaesite surface, and physical adsorption also occurs. However, as for barite and calcite, there is only physical adsorption of SHA on the surfaces. The solution chemistry results show that SHA anions can interact with RE3+, REOH2+, and RE(OH)2+ on bastnaesite surfaces in aqueous suspensions, resulting in bastnaesite flotation.

Modification mechanism of lead ions and its response to wolframite flotation using salicylhydroxamic acid

The surface modification of wolframite by Pb2+ ions and its influence on the flotation of wolframite using a salicylhydroxamic acid (SHA) collector were investigated through microflotation experiments, contact-angle tests, zeta-potential measurements, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results indicated that the addition of Pb2+ ions increased the SHA adsorption onto wolframite surfaces and contributed to the concomitant increases in the hydrophobicity and floatability of wolframite. Results of zeta-potential and XPS analyses confirmed that Pb2+ modification occurred via ion exchange, dehydration reaction, and precipitation reaction, generating Pb-containing complexes on wolframite surfaces. As expected, the Pb2+-modified wolframite exhibited increased interaction with SHA. The results of zeta-potential, FT-IR and XPS analyses indicated that SHA species reacted with Pb-containing complexes adsorbed on the wolframite surfaces, forming the hydrophobic Pb–SHA complexes. These findings verify the great potential of surface modification for strengthening wolframite flotation.

Flotation behavior and adsorption mechanism of salicylhydroxamic acid in artificial mineral anosovite

Flotation is often employed to separate valuable natural minerals and gangue minerals. However, few studies have been conducted on artificial mineral flotation. Anosovite, the primary mineral in titanium slag, is a typical artificial mineral that can be enriched by flotation. In the present work, flotation behavior and adsorption mechanism of anosovite in salicylhydroxamic acid (SHA) solution were studied. The influence of pH and SHA dosage on anosovite flotability was investigated. Micro-flotation test results show that a pH range of 7–8.5 is available for SHA to collect anosovite. A maximum recovery of 93.26% can be obtained with SHA dosage of only 4×10−5 mol/L. In addition, TOC, zeta potential, FTIR, SEM-EDS, and XPS analyses were used to study the adsorption mechanism. Results demonstrated that SHA adsorption is governed by chemisorption. XPS studies further suggested that chemical adsorption occurred at the Ti sites on the anosovite surface.

Studies on the nature of salicyl hydroxamate adsorption at the surface of neodymium oxide

Adsorption of salicyl hydroxamic acid (SHA) on neodymium oxide (Nd2O3) surfaces was studied at different SHA concentrations. The adsorbed surfaces were examined using X-Ray Diffraction (XRD) and Laser Raman Spectroscopy (LRS). XRD results show that the oxide remains intact until stoichiometric amounts equivalent to Nd(SHA)3 were exceeded. At lower concentrations, the behavior appeared to be an ion exchange of SHA with hydroxide as well as carbonates and chlorides. Results are attributed to a monolayer of chemisorbed SHA at low concentrations and multilayers of surface precipitated Nd(SHA)3 at higher concentrations. LRS corroborated these findings. Peaks from the C-H stretching band and C = N vibration bands were identified and areas under the peaks were quantified. Formation of the hydroxamate compound was ascertained from the C = N bands around 1597 cm−1. It was concluded that chelation occurs through chemical bonding of SHA with surface Nd confirming chemisorption and with trivalent Nd confirming surface precipitation. Thermodynamic calculations in the form of solubility speciation diagrams suggest that chemisorption predominates at moderate pH between 6 and 9 and surface precipitation predominates at higher pH between 9 and 12. Adsorption isotherms were determined for the monolayer and found to yield free energy values between physisorption and chemisorption but, due to the reaction being ion exchange, it was concluded to be chemisorption.

Interaction of salicylhydroxamic acid with the surface of MgTi2O5: a study combined DFT and experiment

Salicylhydroxamic acid (SHA) is a typical chelate collector. This study elucidated the effect of steric hindrance on SHA adsorption on the MgTi2O5 surface using density functional theory. The geometry optimisation and electronic structures of SHA ion and the MgTi2O5 (110) surface were calculated. Subsequently, six adsorption configurations of SHA ion on the MgTi2O5 (110) surface were calculated and compared by analysing geometric configuration, bond length, adsorption energy, density of states (DOS), and Mulliken population. The results show that both the oxygen molecules of C╱╲=O and N╱╲O− in SHA ion can coordinate to the metal ion. Steric hindrance affects the formation of a five-membered ring structure. The four adsorption configurations of the newly established structure can effectively avoid steric hindrance, and stable chelate rings are formed. The adsorption energies of the four new configurations range from −300 kJ/mol to −400 kJ/mol, and the bond lengths are about 2 Å. DOS and Mulliken population results indicate that O atoms bond to Ti and Mg atoms. Traditional chelate collector adsorption theory ignores the presence of steric hindrance. At the same time, the species distribution of SHA solution, zeta potential and flotation have also been studied in this paper, and there is a consistency between the calculation and experiment results. This study provides insights into the adsorption mechanism of a chelate collector on a mineral surface.

Flotation Behavior and Mechanism of Anglesite with Salicyl Hydroxamic Acid as Collector

The flotation behavior of anglesite at different pulp pH levels was studied, with salicyl hydroxamic acid (SHA) acting as collector. The results demonstrated the effectiveness of SHA over a wide pH range. Zeta potential, adsorption, and x-ray photoelectron spectroscopy measurements were carried out to explore the interactions between SHA and anglesite. The results showed that the adsorption of SHA on the surface of anglesite was both chemical and physical. Furthermore, experiments with a bench-scale closed-flotation circuit proved that the collector can effectively recover anglesite from zinc-leaching residues (ZLRs). This work sheds new light on flotation of anglesite, providing a significant contribution to understanding of anglesite flotation and its application for disposal of ZLRs.

Depression Mechanism of Strontium Ions in Bastnaesite Flotation with Salicylhydroxamic Acid as Collector

Metal ions are widely present in flotation pulp. Metal ions change solution chemistry and mineral surface properties, consequently affecting mineral flotation. In this work, the effect of strontium ions on bastnaesite flotation with salicylhydroxamic acid (SHA) was investigated by microflotation tests, contact angle measurements, zeta-potential measurements, and X-ray photoelectron spectroscopy (XPS) analysis. Microflotation tests confirmed that the addition of strontium ions decreased bastnaesite floatability, compared with that in the absence of strontium ions. Contact angle measurements suggested that the pretreatment of strontium ions decreased SHA adsorption. Zeta potential measurements confirmed that the bastnaesite was depressed by the adsorption of positively charged strontium species, and the lower adsorption capacity of SHA onto the bastnaesite surfaces was obtained after modifying with strontium ions. XPS analysis demonstrated that strontium ions adsorbed onto the bastnaesite surfaces through the interaction between strontium ions and oxygen atoms of surface ≡ CeOH 0 groups. This occurrence hindered surface Ce sites which chelated with SHA and therefore, decreased bastnaesite floatability.

Rutile flotation with Pb2+ ions as activator: Adsorption of Pb2+ at rutile/water interface

The adsorption of Pb2+ at the rutile/water interface has been studied for the activation of rutile flotation with salicyl hydroxamic acid (SHA) as a collector in this work. This study was performed through measurement of the zeta potential, adsorption capacity, calorimetry and X-ray photoelectron spectroscopy. The experimental results showed that the adsorption of SHA on rutile and the flotability of rutile were significantly improved by the addition of Pb2+. This improvement was attributed to the specific adsorption of Pb2+ in the form of PbOH+, which interacted with the Ti-OH at the rutile surface and formed a surface Ti-O-Pb+ complex. This adsorption followed the Langmuir model. It reversed the zeta potential sign of rutile at pH 5.5⿿6.8 and had a heat of adsorption of ⿿46.71kJ/mol, suggesting the occurrence of a chemiosorptive process.

Flotation and Surface Behavior of Cassiterite with Salicylhydroxamic Acid

The flotation and surface interaction of cassiterite with salicylhydroxamic acid have been investigated in this paper. The results showed that recovery of cassiterite with salicylhydroxamic acid was high at a neutral pH, with the maximum recovery occurring at ca. pH 6.5. When the size of cassiterite is less than 74 μm, coarse particles showed better flotability than the fine ones. The adsorption of salicylhydroxamic acid was also high at a neutral pH. The isoelectric point of cassiterite showed an acidic shift in the presence of salicylhydroxamic acid. A chelate was identified on the cassiterite surface. The results of the adsorption, electrophoretic mobility, and IR spectrum of cassiterite indicated that the adsorption on the cassiterite surface included both physical and chemical adsorption. On the basis of the experimental results, a complex multilayer adsorption model was proposed to illustrate the adsorption on the surface of cassiterite.