Amine Collector Research Articles

Parameters of Collision and Adhesion Process Between a Rising Bubble and Quartz in Long-Chain Amine Solution and Their Correlation with Flotation

The successful adhesion of air bubbles to mineral particles is the crucial to flotation technology. This paper systematically investigates the parameters variation in the dynamic interaction process between a rising bubble and a quartz plate in long-chain amine solutions (dodecylamine, tedecylamine, and octadecylamine). The results show that the type and concentration of long-chain amine affected the collision and adhesion process between bubbles and quartz plates remarkably. The maximum rebound distance (rebound distance after the first collision) of bubbles and the stable-state liquid film thickness gradually decreases with the increase of reagent concentration. Additionally, the collision-rebound duration and induction time shorten accordingly, the surface tension of the solution decreases, the surface hydrophobicity of quartz increases, and the deformation degree and average movement velocity of bubbles decrease. With the increase in carbon chain length, the adsorption form of the amine collector and quartz surface becomes closer to vertical, and the density of water molecules decreases. The recovery of quartz particles is highest with octadecylamine systems, corresponding well with the changing trend in steady-state liquid film thickness. This research provides an effective method for in-depth analysis of the microscopic interaction mechanism between bubbles and mineral surfaces and the prediction of flotation results.

Experimental evidence supporting distinct adsorption configurations of N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine and dodecylamine on apatite surfaces: Quartz crystal microbalance and atomic force microscopy studies

In apatite flotation, a novel amine collector N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine demonstrates a considerably lower collecting ability than dodecylamine. Nonetheless, studies under identical dosage conditions reveal that the adsorption amounts of N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine on apatite surface surpass those of dodecylamine. The collecting efficiency of a collector is traditionally linked to its adsorption amount on the surface of a mineral, suggesting that a collector's efficacy increases with its adsorption amount. However, this study indicates that factors beyond adsorption amount significantly impact a collector's efficiency. Through first-principles calculations, it has been discovered that N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine and dodecylamine possess markedly varied adsorption configurations on apatite surfaces, implying that the variation grant them divergent collecting capabilities in apatite flotation. Supporting these findings, quartz crystal microbalance and atomic force microscopy analyses show the adsorption layer of dodecylamine is nearly triple thickness of N,N-bis(2‑hydroxy-3-chloropropyl) dodecylamine, with a notably different adsorption morphology. These results offer experimental validation of their differing adsorption configurations. This study not only strengthens the theoretical framework for developing selective control technologies of mineral flotation behaviors but also offers more perspectives for designing innovative collector molecules.

Electrochemical action on the flotation beneficiation of ordinary iron ore concentrate

One of the main challenges in processing fresh ferruginous quartzites is to obtain high-quality iron ore concentrates containing more than 70% total iron and less than 1.8% silica to produce DR pellets and hot Briquetted Iron (HBI). Currently, it is widely recognized that the most effective methods to achieve high-quality iron ore concentrates is through reverse flotation using cationic amine collectors in an alkaline medium. However, due to the very fine impregnation of magnetite in quartz, the insufficiently complete release of magnetite even with fine grinding, and the proximity of the flotation (surface) behavior of the separated minerals, high-quality concentrates are not always achievable in the flotation process. Consequently, exploring methods to enhance the efficiency of flotation separation of minerals and improve concentrate quality remains a pertinent issue. Historical studies have shown that electrochemical treatment can adjust the properties of reagents, enhance their effect on specific minerals, and thus control the flotation process. The efficiency of quartz and other silicates flotation by amines significantly depends on the ratio of ionic and molecular forms of the reagent in aqueous solutions of the collector and in the flotation pulp. Altering this ratio can impact the outcomes of reverse cationic flotation of iron ores. It is feasible to change the ratio of the amine forms through electrochemical oxidation or reduction of the reagent solution. Moreover, the electrochemical treatment facilitates the dispersion of the amine in the aqueous medium and its physical adsorption on minerals. Therefore, electrochemical pretreatment of amines can be considered a promising method for intensifying the reverse flotation of iron ore. This paper presents research results aimed at improving the quality of the oversize of the fine screening of ordinary magnetite concentrate from Mikhailovsky GOK, named after A.V. Varichev, through the use of electrochemically treated solutions of cationic amine class collectors in the process of reverse cationic flotation. The research findings confirmed the feasibility of using preliminary diaphragmless electrochemical treatment of reagents Tomamine RA-14 and Lilaflot 811M (esters of monoamine of different composition) for the targeted modification of their properties and for increasing the efficiency of reverse flotation. Consequently, the silica content in the flotation cell product decreased from 1.66–1.7% to 1.51–1.56, with the grade of total iron exceeding 70%.

The application of a novel amine collector, 1-(dodecylamino)-2-propanol, in the reverse flotation separation of apatite and quartz

This study synthesized a novel amine collector, 1-(dodecylamino)-2-propanol (DDAIP), by incorporating a 2-hydroxy propyl group into the molecular structure of dodecylamine (DDA). Flotation experiments showed that utilizing DDAIP collector resulted in a substantial difference of ∼80% in flotation recoveries between apatite and quartz. Employing DDA as the collector yielded a difference of ∼30% in flotation recoveries between the two minerals. DDAIP demonstrated a superior selectivity in the reverse flotation separation of apatite and quartz in comparison to DDA. Zeta potential experiments indicated that, under identical dosages, DDAIP demonstrated increased adsorption capacities on quartz surface in contrast to DDA, whereas the adsorption amounts on apatite surface remained similar for both the collectors. By combining XPS analysis and first-principles calculations, DDAIP demonstrated enhanced chemical interactions with the Si atoms on quartz surface and a greater number of hydrogen bonds with quartz surface compared to DDA. The presence of an isopropyl group between the hydroxyl and secondary amine groups in DDAIP molecular structure leads to steric hindrance, hindering the simultaneous chemical interactions of the O and N atoms in DDAIP with the Ca2+ ions on apatite surface. Thus, the incorporation of the 2-hydroxy propyl group into DDAIP molecular structure does not enhance its adsorption strength on apatite surface when compared to DDA.

Mechanism of Modified Ether Amine Agents in Petalite and Quartz Flotation Systems under Weak Alkaline Conditions

To investigate the flotation separation behavior of petalite and quartz, various methods were employed in this study. These included micro-flotation experiments, a contact angle analysis, zeta potential analysis, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) to explore the separation mechanism of a modified ether amine reagent (L0-503) for petalite and quartz under weakly alkaline conditions. The micro-flotation test results indicated that the modified ether amine collector had a higher collecting ability for quartz than for petalite, with a maximum recovery rate of 93.2% for quartz and a recovery rate consistently below 14% for petalite in the presence of L0-503. This indicates that the modified ether amine reagent can be used as a reverse flotation agent for separating petalite and quartz. The separation mechanism results showed that the modified ether amine reagent had a significantly higher adsorption capacity for quartz than for petalite due to a strong reaction between the quartz and the secondary amine (-NH=) on the modified ether amine collector. Additionally, the electrostatic force and hydrogen bonding between the reagent and quartz further enhanced the adsorption, while no reaction occurred between the reagent and petalite.

Properties and potential application of ozone-oxidized starch for enhanced reverse flotation of fine hematite

In this study, ozone as an eco-friendly oxidant was employed to improve the depressive performance of starch in the reverse flotation of fine hematite. Micro-flotation results showed that ozone-oxidized starch (OS) better depressed hematite flotation as compared to the native starch (NS). Particle surface wettability and size distribution analysis suggested that OS rendered the hematite surface more hydrophilic in the presence of an amine collector while maintaining a comparable flocculation performance to that of NS. Solubility, rheology, carbonyl and carboxyl content measurements, together with atomic force microscopy (AFM) imaging were performed to examine the variations in the structure and properties of starch upon ozonation and their correlation with the depressive performance of starch. It was found that ozone treatment not only increased starch acidity and solubility, but also concurrently depolymerized starch with the yield of low molecular weight derivatives. These favorable changes appeared to be responsible for the superior performance of OS. Furthermore, the stronger interaction of OS with hematite was verified by X-ray photoelectron spectroscopy (XPS).

Evaluation of novel RAFT block copolymers as alternatives to amine collectors

This study introduced and flagged the potential of novel RAFT (reversible addition-fragmentation chain transfer) block copolymers as controllable and tunable collectors to circumvent the main drawbacks associated with amine collectors such as high foaming propensities and generating overly stable froths during froth flotation. A series of RAFT copolymers was evaluated to derive important insights into their abilities to control foamability and foam stability while maintaining high surface hydrophobization. The functional and structural design of the new RAFT copolymers included a hydrophilic block of poly dimethylaminoethyl acrylate quaternised with methyl iodide (PDMAEAI+) which induced a cationic effect, while altering the hydrophobic structure of poly n-butyl acrylate (PBA) determined the degree of surface hydrophobicity engendered on the targeted quartz surface. It was found that the specific number of the incorporated PBA functional groups largely governed the corresponding solubilities and the associated molecular interfacial activity of the copolymers relative to controlling their foaming abilities and surface hydrophobization. As a proof of concept, this study attests that these RAFT copolymers are promising in replacing amine collectors in reverse quartz flotation.

Efficient coal concentration using a short-chain amine-type compound as collector reagent: Flotation and optimization studies

This work presents the flotation of a sub-bituminous coal using 1-butylamine as a short-chain amine collector. The flotation results have been obtained with 1-butylamine (coal yield: 100%) and compared with those achieved with a quaternary amine (coal yield: 95.4%), kerosene (coal yield: 100%) and diesel (coal yield: 95.7%). The best results have been obtained with 1-butylamine. Less depressant effect has been observed with 1-butylamine. The FTIR signals have been attenuated when the coal is conditioned with 1-butylamine. Zeta potential measurements have also been changed after conditioning. The contact angle of water and graphite has decreased from 82.3° to 32.2°. An optimization has been performed using a Box-Behnken experimental design. Flotation has significantly affected by time and collector dosage. The pH is not a significant factor. The optimal conditions for the best efficiency using 1-butylamine as a collector are 2.0 min of flotation and 10-3 mol/L of collector.

Novel polyhydroxy cationic collector N-(2,3-propanediol)-N-dodecylamine: Synthesis and flotation performance to hematite and quartz

To enhance the performance of traditional cationic collector, a novel polyhydroxy amine collector N-(2,3-Propanediol)-N-dodecylamine (PDDA) was designed by introducing one propylene glycol group into dodecylamine (DDA). It was prepared by a nucleophilic substitution reaction, which showed better solubility and hydrophobicity than DDA and was firstly employed as the collector for the separation of hematite and quartz. Flotation tests showed that PDDA had an excellent flotation performance and significantly better selectivity than DDA. In addition, the flotation performance and adsorption mechanism of PDDA on hematite and quartz surfaces were studied using Fourier transform infrared spectroscopy (FT-IR), zeta potential and X-ray photoelectron spectroscopy (XPS) tests. These results demonstrated that the interaction between PDDA and the minerals’ surfaces was mainly electrostatic adsorption and hydrogen bond, while PDDA tended to adsorb on the surfaces of quartz more than that of hematite. Performance optimization of amine collectors by introducing hydroxyl was also verified, which was of great meaning to the design, development, and application of the polyhydroxy cationic collector. In conclusion, PDDA could be used as a potential collector in the flotation separation of quartz and hematite.

Effect of n-octanol on impurity removal by reverse flotation of magnesite ore

Dodecylamine is one of the most commonly used amine collectors for the reverse flotation of magnesite ore. Through a combination of experimental research and computational simulation, the effect of n-octanol on the removal of impurities by the reverse flotation of magnesite ore was studied. The test results show that when the dosage of dodecylamine was 60 mg/L, the flotation rates of magnesite and dolomite were 59.53% and 58.02%, respectively, and the flotation rate of quartz was 97.60%. In the presence of n-octanol, the flotation rate of magnesite decreased to 56.41%, and the flotation rates of dolomite and quartz increased to 61.30% and 99.59%, respectively. The test results show that the addition of n-octanol can improve the selectivity of minerals under the same amount of collector. The adsorption of dodecylamine (dodecylamine and n-octanol) on the surface of magnesite, dolomite and quartz was simulated using quantum chemical calculations based on density functional theory (DFT) and implemented in the CASTEP module of Materials Studio. The results show that dodecylamine can adsorb to magnesite, dolomite and quartz, and the adsorption effect was strongest on quartz. After adding n-octanol, the population value of the bond between the agent and magnesite decreased from 0.19 to 0.17, indicating that the adsorption effect of the agent on magnesite was weakened. The population value of the bond between the drug and dolomite increased from 0.19 to 0.23, indicating that the adsorption effect of the drug on dolomite was enhanced. H28, H29, and H2 in the drug form bonds with O12, O20, and O20 on the surface of quartz (101), respectively, and the population values were 0.43, 0.25, and 0.09, respectively. The adsorption sites of the drug and the quartz were increased, and the adsorption effect of the quartz was markedly improved. The test and simulation results show that the dosage of the agent can be reduced in the presence of n-octanol. N-octanol is not only beneficial to the removal of silicon by amine reverse flotation but also has a certain beneficial effect on the removal of calcium by reverse flotation.

Polyvinyl alcohol/starch-based film incorporated with grape skin anthocyanins and metal-organic framework crystals for colorimetric monitoring of pork freshness

An intelligent film for the visual monitoring of pork freshness was developed using degradable polyvinyl alcohol (PVA)/starch (PS) to immobilize the chromogenic agent of anthocyanins and the volatile amine collector of metal–organic frameworks (MOFs). The indicative property of grape skin anthocyanins (GSAs) was verified using the UV–vis spectra, corresponding to multi-color changing in a pH range of 2–12. Interestingly, the introduction of MIL-101 crystals in the PS/GSAs film significantly increased the specific surface area (approximately 10 times) of the film, the superior volatile amine enrichment capability of MIL-101 enabling the film to detect freshness with a high degree of sensitivity. Moreover, the as-prepared film exhibited good antibacterial properties attributed to MIL-101, which help maintain the freshness of the pork. Owing to these advantages, the PS-GSAs/MIL-101 film was tested to real-timely monitor pork freshness in package, the results were further confirmed basis the total volatile basic nitrogen values.

Mechanical Flotation of Mineral Particles with an Underwater Speaker

ABSTRACT This paper aims to demonstrate a safe, non-chemical approach for improving the efficiency of froth flotation. Laboratory scale flotation tests for quartz particles of different sizes (< 20 µm, 20–38 µm, 38–75 µm, 75–106 µm, 106–150 µm, 150–212 µm) with an ether amine collector at different dosages were conducted in batch mode by using a bottom-driven mechanical flotation cell. An underwater loudspeaker was placed in the flotation pulp phase. The solids concentrations tested were 5% and 20% by weight. The results showed that acoustic sound (at 375 Hz and 77 decibels) increased the flotation recovery by at least 6% over a broad particle size range (i.e. 20–212 micron). The results also suggested applying acoustic sound in a flotation system can improve flotation recovery to a larger extent at a lower reagent dosage. An advantage of having the loudspeaker immersed in the pulp phase rather than in air above the flotation cell was the substantially reduced noise level. The present study provides a potential approach for improving flotation performance and reducing the chemical reagent consumption in flotation cells.

Development and utilization of a novel hydrogen bonding enhanced collector in the separation of apatite from quartz

• Hydrogen bond functional group is introduced into amine collector molecules. • A novel and high-efficiency collector HDMEA was synthesized in laboratory. • Better selectivity was achieved by regulating the size of the polar group. • The separation performance of HDMEA was superior to DDA. In the light of the adsorption difference of cationic collectors on quartz and apatite, an additional hydrogen bond functional group can be introduced into the traditional collector molecule—dodecylammonium acetate (DDA) to achieve high-efficient separation of minerals. In this study, a new surfactant—N-(2-hydroxy-1, 1-dimethylethyl) dodecylamine (HDMEA) was synthesized in our laboratory and acted as a new-type amine collector in the reverse flotation separation of apatite from quartz. The results of micro-flotation tests indicated that the separation performance of HDMEA was significantly better than that of DDA. When the concentration of HDMEA was 20 mg/L at pH 6.43, the apatite with 38.57% grade and 95.8% recovery could be achieved in mixed-flotation tests. The adsorption mechanism of DDA and HDMEA on quartz and apatite was comparably explored by the measurements of zeta potential, FTIR, contact angle, and AFM as well as the DFT calculations. These results demonstrated that improving the hydrogen bonds adsorption on quartz (by –NH- and –OH groups) and increasing the steric-hindrance effect on apatite help to achieve efficient flotation separation of quartz and apatite.

Flotation separation of quartz and dolomite from collophane using sodium N-dodecyl-β-amino propionate and its adsorption mechanism

Flotation is the most widely used method to effectively separate dolomite and quartz from collophane. Conventional amine collectors can’t effectively remove silicate minerals due to their poor selectivity, thick foam and weak collective performance. In this work, a novel amphoteric collector sodium N-dodecyl-β-amino propionate(C12Giy) was synthesized by methyl acrylate method. The strength of C12Giy's collective performance for three minerals was investigated by the micro-flotation test. In addition, the adsorption mechanism of C12Giy on the surface of three minerals was studied by zeta potential test, infrared spectroscopy and XPS test. The micro-flotation results show that C12Giy has a strong collection performance for dolomite and quartz, but weaker for collophane. It was also noted that when the pH is 3 and the concentration of C12Giy is 30 mg/L, collophane and quartz can be effectively separated. Similarly, when the pH is 5 and the C12Giy concentration is 30 mg/L, the effective separation of collophane and dolomite can be achieved. Zeta potential test and infrared spectrum analysis showed that C12Giy was adsorbed on surface of collophane and quartz by electrostatic attraction at pH= 3, while it is chemical adsorption on the surface of dolomite at pH= 5. The XPS analysis further indicated that the exposed magnesium ions on the surface of dolomite are crucial for the selective adsorption of C12Giy on dolomite. On the one hand, Magnesium ions, as an important component on the surface of dolomite rather than collophane, enhance the chemical adsorption of C12Giy on dolomite. On the other hand, it increases the total interaction energy of dolomite with quartz particles by adding C12Giy, which in turn increases their electrostatic attraction with the bubbles. Therefore, C12Giy can be utilized as a potential collector to separate dolomite and quartz from collophane.

Influence of polysorbate 80 on flotation of zinc oxide ores with amine collector

Influence of polysorbate 80 on flotation of zinc oxide ores with amine collector

Potential application of an eco-friendly amine oxide collector in flotation separation of quartz from hematite

The development of eco-friendly collectors is an essential issue of much concern in mineral flotation processes. In this work, an eco-friendly amine oxide, N,N-Dimethyl aminopropyl dodecylamide oxide (LAO), was introduced as the collector in flotation separation of hematite and quartz. Compared with conventional amine collector dodecylamine (DDA), LAO with low toxicity has better flotation performance and superior selectivity in the natural slurry. With 10 mg/L LAO, the recovery of quartz and hematite is respectively 94.72% and 10.50%, while using the same dosage of DDA, the quartz recovery is only around 40% and the hematite recovery is 23%. The median effective inhibition concentration (EC50) of LAO for Daphnia magna is 328.44 mg/L, indicating LAO is a nontoxic compound to aquatic organisms. Therefore, LAO is a promising eco-friendly collector to apply in the separation of quartz from hematite.

Synergistic Effect of DBP with CTAB on Flotation Separation of Quartz from Collophane

Collophane is difficult to upgrade by reverse flotation of quartz with amine collector alone due to its low grade, complex structure, fine dissemination grain size, etc. This investigation was conducted to explore the synergistic effect of dibutyl phthalate (DBP) as a surfactant with cetyltrimethyl ammonium bromide (CTAB) as the collector on the separation of quartz from collophane by means of micro-flotation tests, surface tension and aggregate size measurements, and froth water mass fraction/recovery characterization. It was found that DBP reduced the surface tension of the reagent solution and enhanced the collision probability between bubbles and quartz particles by increasing the size of aggregates through increased hydrophobic interaction between the quartz particles and DBP droplets. The addition of DBP reduced the entrainment of fine collophane particles as a result of improved defoaming and increased the flotation recovery of quartz without resulting in any flotation of collophane at dosages lower than 200 mg/L. Flotation test results with the binary artificial mineral mixture showed that DBP improved the P2O5 recovery, SiO2 rejection, and P2O5 grade by up to 7%, 12%, and 1%, respectively.

Effect of Ether Mono Amine Collector on the Cationic Flotation of Micaceous Minerals—A Comparative Study

Micaceous minerals, known as layer silicates, are counted mostly as the gangue minerals associated with valuable minerals, especially iron oxides. They mainly reject through the reverse flotation process using the cationic collectors, e.g., ether amines, to improve process sustainability. Although ether amines have been applied for floating the wide range of silicates, few investigations explored their adsorption behaviors on the micaceous minerals. In this study, flotation of phlogopite, biotite, and quartz (for comparison purposes) in the presence of Flotigam®EDA (EDA) (commercial ether monoamine collector), at pH 10 was investigated through the single mineral micro–flotation experiments. Adsorption behaviors were explored by the contact angle, residual surface tension measurements, and zeta potential analyses. Micro–flotation outcomes indicated that the quartz floatability was more than phlogopite and biotite. In the presence of 30 mg/dm3 EDA, their recoveries were 97.1, 46.3, and 63.8%, respectively. Increasing EDA concentration made a substantial increase in micaceous minerals’ floatability. Adsorption assessments confirmed that increasing the EDA concentration resulted in higher adsorption of EDA onto the surface of micaceous minerals than the quartz (all by physical adsorption). Such a behavior could be related to the nature of micaceous minerals, including their layer structure and low hardness.

Study on quantitative structure-biodegradability relationships of amine collectors by GFA-ANN method

In this study, the biodegradability of 17 amine collectors, categorized by fatty amine, quaternary ammonium compounds and oxygen-containing amine collectors, are tested with the Closed Bottle Test for 90 days, and the results indicate most amine collectors are not readily biodegradable. The oxygen-containing amine collectors have the best biodegradability due to the introduced oxygen-containing functional groups, subsequently fatty amine collectors with branched chains, while the tested quaternary ammonium compounds all have poor biodegradation ability. Besides, we search for and calculate 35 molecular descriptors to develop the quantitative structure biodegradability relationship (QSBR) of amine collectors. With the Genetic Function Approximation (GFA) algorithm, two sets of important molecular descriptors related to biodegradability (q) of amine collectors are selected from 35 molecular descriptors. Based on internal and external validations, the robust and reliable non-linear QSBR model with the squared correlation coefficient above 0.99 is determined via Artificial Neural Network (ANN) method, where the descriptors are respectively CL, N, ELUMO, δv2, indicating the biodegradable ability of amine collectors is correlated with the alkyl chain lengths (CL), the number of nitrogen atom-containing compounds (N), energy of the lowest unoccupied molecular orbital (ELUMO) and valence second-order connectivity index (δv2).

An HPLC Method for the Determination of Amines in Flotation Pulp Based on Derivatization

Alkyl amines are surfactants used as quartz collectors in the reverse flotation of phosphate ores. It is important in both research and industrial practice to quantify amine concentration in the solution and/or wastewater. A simple and rapid method using high-performance liquid chromatography (HPLC) was developed to quantitatively determine the concentration of amine collectors (including dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine) in a mineral flotation system. The method involved a sample derivatization procedure with 9-fluorenyl methoxycarbonyl chloride (FMOC-Cl) and separation/determination by HPLC coupled with a fluorescence detector. The calibration curves showed good linearity (R2 > 0.9956) in the range of 0.20–5.00 µg/mL, and the recoveries of dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine were in the ranges of 84.93–97.64%, 89.93–101.92%, 85.29–98.37%, and 93.57–103.26%, respectively. The method was successfully used to quantify amines in wastewater from flotation experiments and artificial flotation wastewater (amine solution after activated carbon adsorption). The results from the analysis of four amines in the solution demonstrated that the proposed method is suitable for the simultaneous determination of amines in flotation pulp and wastewater.