Floatability Of Quartz Research Articles

Optimization of hematite and quartz BIOFLOTATION by AN artificial neural network (ANN)

Mineral flotation using microorganisms and/or their derived products is called “bioflotation.” This is a promising process due to its low environmental impact; however, it is also a very complicated process, due to its multidisciplinary character, involving mineralogy, chemistry, and biology. So, the optimization of this process is an important challenge. This study assessed the implementation of a quadratic model and an artificial neural network (ANN) for the optimization of hematite and quartz floatability and recovery. The flotation process was carried out using a biosurfactant extracted from the Rhodococcus erythropolis bacteria. Quadratic model was adjusted by genetic algorithms techniques and validated using analysis of variance (ANOVA). Multilayered feed-forward networks were trained using a backpropagation algorithm, implemented using MATLAB R2017a. The topologies of the neural networks included 2 neurons in the input layer and 1 neuron in the output layer in both models, while the hidden layer varied according to the performance of the model. The results showed that the ANN model can predict the experimental results with good accuracy, when compared to quadratic model. Sensitivity analysis showed that the studied variables (pH and biosurfactant concentration) have an effect on the mineral recovery.

Utilization of benzyl aminopropyl dimethoxymethylsilane as collector for the reverse flotation of silicate minerals from magnetite

In this paper, a collector benzyl aminopropyl dimethoxymethylsilane (BADM) was utilized for the reverse flotation of silicate minerals from magnetite. The micro-flotation results showed that good floatability of quartz, garnet, olivine and magnetite was obtained at pH 8 in the presence of BADM. However, the depressant, soluble starch, showed a selective depression for magnetite. Separation of the three silicate minerals from magnetite was performed by mixed- mineral flotation experiments with the soluble starch as depressant and BADM as collector. In order to probe the validity of these findings, zeta potentials were measured and the results showed that conditioning of the silicates with soluble starch prior to BADM did not prevent the adsorption of BADM while the adsorption on the magnetite surfaces was decreased.

Enhancing the purity of magnesite ore powder using an ethanolamine-based collector: Insights from experiment and theory

Magnesite ore powder is the primary raw material used to prepare refractory magnesia. With the depletion of high-grade magnesite, methods to reduce the impurities and improve the quality of magnesite ore powder are urgently required. In this study, an ethanolamine-based surfactant, bis (2-hydroxyethyl) dodecylamine (BHDA), was first introduced into the flotation of magnesite ore as a novel collector, and the possibility of improving the purity of the ore was investigated by experiment and theory. Flotation tests, X-ray photoelectron spectroscopy, Fourier-transform-IR spectroscopy, and zeta potential measurements were carried out to study the behaviors and mechanisms by which the collector enhances the purity of magnesite ore powder. The flotation results revealed the noticeable difference in the floatability of quartz, magnesite, and dolomite when combined with the collector over a wide range of pulp pH values (4.18–9.17). The analytical results obtained from FTIR spectra, XPS, and zeta potential measurements indicate that BHDA was readily adsorbed on the surface of quartz, mainly by electrostatic and hydrogen bonding interactions, whereas it was adsorbed on the surfaces of magnesite and dolomite by weak electrostatic interactions. By introducing a hydroxyethyl group to the tertiary amine collector, more hydrogen bonds can form with the surface of quartz, strengthening the adsorption stability. Thus, compared to the traditional collector, dodecylamine, BHDA showed better desilication and purification performance for magnesite ore powder. Meanwhile, our results show that the simpler reagent system and process flow makes BHDA promising for the industrial purification of magnesite ore powder.

Developing Effective Separation of Feldspar and Quartz While Recycling Tailwater by HF Pretreatment

The effect of hydrofluoric acid (HF) pretreatment on flotation of feldspar and quartz using dodecylamine (DDA) as collector was investigated by micro-flotation, zeta potential, pyrene fluorescence spectroscopy, attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and bench scale flotation. The micro-flotation tests revealed that there was little difference in the flotation of feldspar and quartz at pH 2, using H2SO4 as pH regulator. After HF pretreatment, the floatability of feldspar significantly increased while the floatability of quartz showed no change. HF pretreatment resulted in leaching of SiO2 and enrichment of Na, K and Al on the feldspar surface. Consequently, the negative surface charge of feldspar increased at pH 2, which allowed for the flotation separation of the feasible minerals. This took place via an increased electrostatic adsorption between DDA and Na, K, Al on the feldspar surface, which effectively increased its hydrophobicity and as a result, improved the floatability of feldspar. An alternative process which exhibited effective separation of quartz and feldspar while recycling the tailwater from the flotation was proposed.

Smart collectors: Control of the wettability and floatability of quartz with UV irradiation

Quartz is a hydrophilic mineral that usually associates with other ores. In this paper, the effect of UV stimuli on the wettability and floatability of quartz was studied. An azobenzene-containing surfactant was synthesized and its structure was identified by 1H NMR. We used UV–vis and 1H NMR spectra of the surfactant to study its photoisomerization. After UV irradiation of the surfactant molecular, the trans isomer concentration decreases and the cis isomer concentration increases; both the aromatic protons of the azobenzene moiety and aliphatic protons experience an upfield shift, indicating that the surfactant molecular isomerizes from the trans isomer to the cis form. We used contact angle measurements to demonstrate that UV irradiation decreases the hydrophobicity of the quartz and increases the adhesion tension of the surfactant on quartz. The results of flotation tests demonstrate that the azobenzene-containing surfactant has higher performances than alkyl amine salt, and UV irradiation improves the selectivity of the azobenzene-containing surfactant in the flotation of quartz. This study demonstrates that the azobenzene-containing surfactant can be used as a light-responsive collector for quartz in the flotation of phosphate ores.

The Effect of Quartz on the Flotation of Fine Wolframite with Octyl Hydroxamic Acid

The influence of quartz on the flotation of fine wolframite using octyl hydroxamic acid (OHA) as the collector was investigated by micro-flotation tests, inductively coupled plasma (ICP) measurements, adsorption experiments, zeta potential, and Fourier transform infrared spectroscopy (FT-IR) analysis. Micro-flotation tests showed that a large difference in floatability existed between fine wolframite and quartz in the pH range of 7.0 to 10.0. However, in a synthetic mixture, the flotation separation of fine wolframite from quartz became more difficult as the particle size of the latter decreased. When a dissolved solution of wolframite was used as the flotation medium, quartz floatability improved significantly. Zeta potentials of quartz particles shifted positively in the dissolved solution of wolframite compared to distilled water, especially at a pH level of 7.0–10.0, which was attributed to the metal ions dissolved from the wolframite being adsorbed onto the quartz surface. The surface activation of quartz led to an increase in the OHA adsorption and made the surface hydrophobic. FT-IR analysis further demonstrated that OHA could adsorb onto the activated quartz surface through a dominantly chemical process.

Photofoams and flotation mechanism of an azobenzene-based surfactant on quartz

In this study, the flotation behavior and mechanism of an azobenzene-based surfactant on quartz were studied by micro-flotation tests, zeta potential measurements and adsorption analysis. The stability of foams produced by the surfactant can be controlled by ultraviolet (UV) light irradiation. Photocontrolled foams improve the floatability of quartz due to the significant changes in the foam properties. UV light irradiation decreases the zeta potential values of quartz and the adsorption of the surfactants on quartz. The azobenzene-based surfactant predominantly adsorbed to quartz compared to apatite.

Effect of butanol on flotation separation of quartz from hematite with N-dodecyl ethylenediamine

In order to investigate the effect of butanol on quartz flotation when N-dodecyl ethylenediamine (ND) was used as collector, single mineral flotation and artificial mixed mineral (hematite and quartz were mixed at a mass ratio of 3:2) separation were conducted in the laboratory. Experimental results indicated that addition of butanol could improve the collecting performance of ND on quartz and enhance the floatability of quartz. Best flotation recovery of quartz was obtained when butanol was mixed with ND at a mass ratio of 1:1. Moreover, the molecular structure of alcohols had a significant effect on mineral recovery. Best separation efficiency could be obtained when tert-butanol was added as it had the largest cross-sectional area. Zeta potential measurements indicated that alcohols could strengthen electrostatic adsorption between quartz and collector. Molecular dynamic simulations revealed that co-adsorption of alcohols along with ND had taken place on the quartz surface, and ND/tert-butyl combinations were more easily absorbed on the quartz surface.

The entrainment effect on the performance of iron ore reverse flotation

An iron ore mineral processing plant in Brazil treating Itabirite ore was assessed by sampling a circuit consisting of Wemco 144 mechanical cells, as part of the AMIRA P9P collaborative research project. This paper presents and discusses the results of entrainability, water recovery and quartz and hematite grades associated to hydrodynamic parameters. The results indicated strong correlation between water recovery and hematite losses which was intensified by the operating conditions of the circuit.A potential alternative to reduce the hematite losses through entrainment and to increase quartz removal was to modify the traditional circuit design to treat rougher and cleaner/recleaner tails in different stages. In addition, the scavenger residence time must be matched to the quartz floatability. Changes to design and operation of these circuits are needed to sustain concentrate recovery and grade as iron ores become finer.

Effect of carbonate minerals on quartz flotation behavior under conditions of reverse anionic flotation of iron ores

Reverse anionic flotation of carbonate-containing iron ores is quite a challenging process. Studies on this ores conducted in many laboratories or beneficiation plants have obtained poor concentrate grades and separation between quartz and iron minerals, even when valuable minerals are adequately liberated. The presence of carbonate minerals, such as siderite, causes a detrimental effect on quartz flotation recovery (froth product) and separation selectivity between quartz and iron minerals. In this work, the effect of carbonate minerals on quartz flotation from iron mineral was investigated using sodium oleate as collector, starch and calcium as regulators. Microflotation, adsorption, PHREEQC calculation, and Fourier transform infrared spectroscopy (FTIR) measurements were conducted in the investigation. Carbonate minerals (i.e., siderite and dolomite) adversely affected the floatability of quartz and separation between quartz and hematite. Starch dosage experiment results clearly showed that the reduction of quartz recovery in the presence of carbonate minerals was mainly related to starch. In addition, mineral dissolution and sodium carbonate dosage experiments evidently exhibited that CO32− dissolved species of carbonate minerals passively affected quartz flotation recovery. By contrast, both starch and CO32− dissolved species of carbonate minerals adversely affected the flotation recovery. FTIR showed that the strong drop-off in quartz recovery in the presence of carbonate minerals was due to the adsorption of CaCO3 precipitations on quartz surfaces and further their interaction with starch molecules. The appearance of CaCO3 precipitations was caused by reaction of Ca2+ from the hydrolysis of CaCl2 and CO32− dissolved species of carbonate minerals. To decrease the passive effect, a potential strategy to improve the flotation performance of iron ores that contain carbonate minerals at strong alkaline pH is suggested to remove carbonate minerals before separation between hematite and quartz.

Effect and mechanism of siderite on reverse flotation of hematite

The effects of siderite on reverse flotation of hematite were investigated using micro flotation, adsorption tests, and Fourier transform infrared spectroscopy. The flotation results show that interactions between siderite and quartz are the main reasons that siderite significantly influences the floatability. The interactions are attributed to dissolved siderite species and fine siderite particles. The interaction due to the dissolved species is, however, dominant. Derjaguin-Landau-Verwey-Overbeek (DLVO) theoretical calculations reveal that adhesion on quartz increases when the siderite particle size decreases and that fine particles partly influence quartz floatability. Chemical solution calculations indicate that the dissolved species of siderite might convert the surface of active quartz to CaCO3 precipitates that can be depressed by starch. The theoretical calculations are in good agreement with the results of adsorption tests and FTIR spectroscopy and explain the reasons why siderite significantly influences reverse flotation of hematite.

Comparison of microwave irradiation and oxidation roasting as pretreatment methods for modification of ilmenite physicochemical properties

The effect of microwave irradiation and oxidation roasting (as a conventional heating method) on ilmenite surface properties and its flotation behavior were compared. This comparison was performed by carrying out micro and laboratory scales flotation tests, XPS, XRD, FTIR, SEM and microprobe analyses, zeta potential and contact angle measurements. The micro scale flotation experiments indicated that the ilmenite flotation recovery improves from 73.5% to almost 94% and 91% after pretreatment by microwave irradiation and oxidation roasting, respectively. This is in good concordance with the results of XPS analysis showing the increase of Fe3+ content from 48.5% to 66% after pretreatment by microwave irradiation and 64.8% after oxidation roasting. As evidenced by FTIR analysis, zeta potential and contact angle measurements, the improvement in ilmenite floatability and hydrophobicity after pretreatment is due to the entrance of more oleate ions into the Helmholtz layer and the increase of the formation of ferric iron oleate which is more insoluble than the ferrous one. The surface properties and floatability of quartz does not change significantly after pretreatment by both methods.In ore flotation experiments, when the grinded ore was pretreated by microwave irradiation and oxidation roasting, without significant changes in the TiO2 grade of flotation concentrate, the recovery of TiO2 improves from 65.4 to 76.2% and 73.7%, respectively. In the case of non-grinded ore, the recovery of TiO2 increases up to 79.8% and 70.2% after microwave irradiation and oxidation roasting, respectively. The decrease of iron content in the gangue minerals increases the improvement of TiO2 grade and recovery after pretreatment by both methods. Using microwave irradiation as a pretreatment process, the improvement in the recovery of TiO2 and separation efficiency is more than those of oxidation roasting. In addition, microwave irradiation reduces the consumption of activation and depressant agents.

Ionic liquids as novel quartz collectors: Insights from experiments and theory

Application of quaternary ammonium based ionic liquids (IL’s) as flotation collectors of quartz has been investigated. Effect of number of carbon atoms in the four identical alkyl chains of the IL’s has been studied. The adsorption behaviour of the IL’s on the quartz surface is ascertained through FTIR, XPS and molecular modelling. The FTIR peak at 2900cm−1 indicates the adsorption of the IL’s onto the quartz surface, which is further substantiated by the appearance of the N (1S) peak in the X-ray photoelectron spectra (XPS). Curve splitting data of C (1S) suggests the maximum adsorption for the IL tetrahexylammonium iodide (THEX). Flotation results of pure quartz using ionic liquids are found to be better compared to the conventional collectors such as dodecylamine (DDA) or cetyltrimethylammonium bromide (CTAB). It is possible to float 92–100% quartz by using a THEX concentration of 4.8 × 10−5M. IL collectors are further applied in the flotation of a low grade banded hematite quartzite (BHQ) iron ore with ∼38% Fe. It is possible to achieve an iron concentrate of 63.6% Fe at 63.2% recovery by using THEX as the collector. Molecular simulations using the COMPASS forcefield explains the IL–quartz adsorption mechanism comprising of both electrostatic and van der Waals forces. Floatability of quartz has been correlated with the surface coverage and adsorption energy calculations. The IL’s used here are found to be better quartz collectors than the conventional ones as they show better collecting efficiency in lower dosages. Flotation using these IL’s does not require frothers which is an added advantage compared to the conventional collectors.

Influence of microwave irradiation on ilmenite flotation behavior in the presence of different gangue minerals

As a pretreatment method, microwave irradiation was applied to modify ilmenite surface properties and to improve its flotation behavior in the presence of different gangue minerals including olivine, pyroxene, tremolite, clinochlore and quartz. The flotation experiments were carried out in both micro (Hallimond-tube) and laboratory (flotation cell) scales. The microflotation experiments showed that the ilmenite surface irradiation converts Fe2+–Fe3+ ions, characterized by XPS analysis, improving the floatability. This is due to the increase of oleate adsorption and the formation of more insoluble ferric iron oleate as evidenced by FTIR analysis and zeta potential measurements. In addition, this pretreatment decreases the consumption of flotation reagents. The microwave irradiation does not have a significant effect on surface properties and floatability of quartz. In laboratory scale flotation experiments, when quartz is the main gangue mineral, the TiO2 grade and recovery of flotation concentrate improved from 27.1% to 28.3% and 85.3% to 92.7%, respectively by using microwave irradiation. In the presence of tremolite and clinochlore containing almost 12.4% Fe, the microwave irradiation improved the TiO2 grade and recovery from 21.3% to 22.1% and 71% to 82.5%, respectively. In the case of olivine and pyroxene with 30.1% Fe, the recovery of TiO2 increases from 66.9% to 69.1%. In the flotation of the ore sample containing 24.5% Fe, the microwave irradiation improves the recovery of TiO2 in the ilmenite concentrate from 65.4% to 76.2%. In a general result, in the flotation of ilmenite from different gangue minerals, the separation efficiency and selectivity index have a negative correlation with the iron content of gangue minerals.

Tribochemical treatment of feldspathic-quartz ore in froth separation

Principles of tribochemical treatment of minerals have been developed to control the mineral flotation ability. It is found that floatability of quartz depends on the quartz electronic structure. Using feldspathic-quartz ore as an example, the authors illustrate the improvement in separability of the minerals and the ecological friendliness of the tribochemical treatment.

Collecting performances of N-dodecylethylene-diamine and its adsorption mechanism on mineral surface

The collecting performances of N-dodecylethylene-diamine (ND) to quartz and hematite were studied via single mineral flotation. Experimental results show that ND has stronger collecting ability to quartz than hematite. Different floatability of quartz and hematite was presented in the existence of depressant. Compared with lauryl amine, ND has stronger collecting performances to quartz. Satisfied separation result of artificially mixed sample was acquired with iron grade of concentrate of 59.92% and iron recovery of 88.85% when pulp pH value was 7.27 with 41.7 mg/L collector and 3.33 mg/L starch. Polar group properties calculation results indicated that ND has stronger collecting capability and better selectivity than lauryl amine. Measurement results of zeta-potentials and infrared spectrum showed that hydrogen bonding adsorption and electrostatic adsorption occur between the surface of ND and quartz.

Utilization of humic acid as a depressant for hematite in the reverse flotation of iron ore

In the present work the utilization of humic acid as a depressant for hematite in the iron ore flotation process was studied taking into consideration its physicochemical properties. Contact angle measurements of hematite and quartz were performed using a computer controlled Ramé-Hart goniometer. After conditioning with humic acid at pH 10.2, at low dodecylamine concentrations, hematite presented a much lower contact angle as compared to that of quartz under the same conditions. Microflotation tests were carried out using an EMDEE flotation apparatus. Initially, the two minerals were studied individually. The results showed that, depending of the humic acid and dodecylamine concentrations, the floatability of quartz was higher than 90% and 61% of the hematite was depressed. The flotation of the mixture of the two minerals (25% quartz and 75% hematite) was subsequently studied. The hematite recovery was higher than 90% in the depressed concentrate which assayed 86.0% Fe 2O 3. The results suggest that humic acid could be used as an alternative for starch in the iron ore flotation process.

石英石鹸浮選における銅イオン活性について

The floatability of quartz in the presence of Cu ion was investigated by flotation test with varying amounts of CuSO4 and Na-Oleate under various pH values. Also to account for the mechanism of Cu activation, the behavior of Cu ion during flotation was studied.From results obtained the following conclusions are summarized:1) Maximum floatability is found at about 1: 1 moil ratio of Cu to Na-Oleate and excess of Na-Oleate tends to depress quartz.2) Optimum pH range of Cu activation is from about 6 to 10.5, which is considerably narrower, compared with that of Ba and Ca activators.3) Cu in the form of Cu (OH) 2 can be adsorbed on quartz surface, which may be expected to act as the linkage between quartz surface and hydrophobic film of Cu-Oleate.