Quartz Recovery Research Articles

Novel Insights into the Hydroxylation Behaviors of α-Quartz (101) Surface and its Effects on the Adsorption of Sodium Oleate

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca2+-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca2+ in the form of Ca(H2O)3(OH)+ can greatly promote the adsorption of OL− on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL− ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents.

Flotation recovery of rare earth oxides from hematite–quartz mixture using sodium oleate as a collector

Froth flotation plays a significant role in the beneficiation of rare earth elements (REE) minerals from differing ores. Monazite has been identified as one of the principal REE minerals in most iron oxide silicate rich tailings generated in Australia from the extraction of primary commodities such as copper and gold. These tailings generally contain hematite and quartz as the major gangue minerals. A previous investigation has identified almost identical flotation response between monazite and hematite in the presence of anionic collectors. Therefore, it is necessary to investigate the feasibility of selective flotation of rare earth oxides (REO) in monazite from hematite–quartz mixtures, to identify cost-effective processing methods. The flotation conditions for selective REO separation from model minerals mixtures were tested in a 1.2 L Denver flotation cell using sodium oleate as a collector. Sodium silicate and starch were tested as depressants for hematite and quartz. Results from the flotation tests revealed that the increased dosage of sodium oleate led to an increase in REO recovery with a corresponding decrease in upgrade, and increased hematite (Fe2O3) and quartz (SiO2) recoveries. In the absence of depressants, the separation of REO from a low grade mixture (0.83% REO feed grade) was unselective, where 3000 g/t sodium oleate recovered 98% REO at a grade of 1.31% (enrichment ratio, E = 1.58) along with 77% Fe2O3 and 37% SiO2 recoveries. However, the depressants reduced the flotation recovery of Fe2O3 and SiO2, which was shown by an improvement in REO grade. The flotation recovery of REO decreased to 84% with a corresponding increase in grade to 4.13% when 1000 g/t sodium silicate was used in the presence of 3000 g/t sodium oleate. Furthermore, 1000 g/t starch in the presence of 3000 g/t sodium oleate increased REO concentrate grade to 5.56% although the recovery decreased to 65%. Subsequently, a rougher–scavenger flotation test conducted with the mixed depressants (sodium silicate: starch, 1:1) produced a final concentrate recovering 61% REO at a grade of 6.25%. This study has shown that REO can be separated selectively from hematite–quartz rich mixtures by flotation when using sodium oleate as the collector and sodium silicate and starch as depressants.

Intensification of interfacial adsorption of dodecylamine onto quartz by ultrasonic method

Besides being a versatile mineral resource, quartz is also a common gangue mineral in mineral separation. The separation and enrichment of quartz minerals are particularly important in industrial production. Cationic surfactants of dodecylamine (DDA) is mainly used as collector in the quartz flotation as it consists of hydrophilic amino group which attach to the quartz surface, and the hydrophobic carbon-chain groups which make the quartz hydrophobic. So the adsorption behaviour of DDA is vital to the quartz flotation. In this paper, we examine an ultrasonic method for enhancing the adsorption of DDA in the froth flotation of quartz. The adsorption mechanism of the DDA collector onto quartz is systematically investigated via Fourier transform infrared spectroscopy (FTIR) measurements, adsorption heat measurements, adsorption amount tests, contact angle analysis, and induction time tests, and X-ray photoelectron spectroscopy (XPS) analysis. Our results indicate that ultrasonication does not change the functional groups of the DDA, however, the adsorption intensity with an adsorption heat of −26.56 J/g between ultrasonically treated DDA and quartz is fairly large. The adsorption amount of DDA onto quartz significantly increases after ultrasonically treated without increasing its concentration, and the maximum contact angle of quartz particles after conditioning by the ultrasonically treated DDA increase from 53.07° (for untreated DDA) to 66.13° at the concentration of 8 × 10−5 mol/L. In bubble attachment tests, the induction time between quartz particles and a bubble is observed to decrease from 30 ms to 20 ms compared to that without ultrasonic treatment, and coupled with a greater attachment performance of the DDA solution with ultrasonic treatment. And the XPS analysis confirms the adsorption of ultrasonically treated DDA onto quartz surface. Further, we perform micro-flotation tests to verify the enhanced adsorption of the ultrasonically treated collector onto the quartz surface for different initial concentrations; the results indicate that ultrasonication of DDA significantly improves the flotation recovery of quartz, particularly at moderate collector concentrations. This study is beneficial for understanding the interfacial adsorption and the ultrasonic intensification of DDA onto quartz particles.

Flotation Behavior, Collector Adsorption Mechanism of Quartz and Feldspar-Quartz Systems Using PEA as a Novel Green Collector

A novel green cationic surfactant Poly (propylene glycol) bis (2-aminopropyl ether) (PEA) with multiple amine groups was utilized as a collector for flotation separation of quartz from feldspar-quartz associated ore (FQA) without acid (particularly, HF) and alkali. The collecting performances and the adsorption mechanisms of PEA on the quartz/FQA were investigated through flotation experiments, ICP-OES, XRD, Zeta potential, FTIR and XPS measurements. A remarkable separation of the quartz from FQA has been realized in an environmental friendly way. The froth flotation results show that the flotation recovery of quartz is 97.79% and that of FQA is 19.30% at pH 9.00–9.50 with 10−4 M PEA when the particle size ranges from 150 to 270 μm. The results of batch flotation, ICP-OES and XRD analyses show that the first flotation product is almost quartz, while more feldspar and little quartz exist in the sink product when compared with the FQA feed. The mechanism of PEA acting as the collector for the separation of quartz/feldspar has been investigated. The PEA is adsorbed on the quartz surface by electrostatic and hydrogen bonding interaction with ─NH3+ /─NH2 head groups, while is less adsorbed on the feldspar surface due to electrostatic repulsion between the K+ / Na+ ions and the positively charged ─NH3+/─NH2 head groups of PEA. A conceptual adsorption model of the PEA cationic collector on the quartz and the FQA surfaces has been proposed.

Synthesis and utilization of a gemini surfactant as a collector for the flotation of hemimorphite from quartz

A gemini surfactant, N,N′-dilauroyl ethylenediamine sodium dipropionate (DNET), was applied as a novel collector for improving the flotation separation efficiency of hemimorphite from quartz. Flotation tests of hemimorphite separation from quartz with DNET were carried out to determine the flotation performance. The adsorption mechanism of DNET on the hemimorphite surface was analysed based on zeta potential measurement, Fourier transform infrared (FTIR) spectroscopic analysis, and XPS detection. The results indicated that DNET had strong collecting ability on hemimorphite. When the DNET dosage was 175.0 mg/L and the slurry pH was 6.83, more than 84% of the hemimorphite could be floated. The quartz recovery was less than 8.00% in the experimental process. The artificially mixed mineral separation results demonstrated that DNET could effectively separate hemimorphite from quartz. The flotation separation results showed that the grade and recovery of zinc were 49.40% and 99.61%, respectively, when the DNET dosage was 150.0 mg/L and the slurry pH was 8.56. The adsorption mechanism analysis indicated that chemical adsorption occurred between DNET and the Zn site on the hemimorphite surface.

Non-HF collectorless flotation of quartz

Pure mineral flotation experiments have demonstrated that quartz can be floated without a collector, in solutions containing an inorganic acid (e.g. H2SO4) and sodium fluoride (NaF). Excellent quartz recoveries, similar to that of previous investigations with aqueous solutions containing hydrofluoric acid (HF), have been achieved with lower fluorine concentrations and a more optimal F/H ratio when combining separate sources of H and F instead of using only HF.

Effects of Porosity and Electrical Resistance of Metallurgical Coke and Semicoke on Silicon Recovery in an Electric Arc Furnace

The effects of the electrical resistance and porosity of two types of coke used in ferrosilicon electric arc furnaces were investigated to determine the silicon recovery from quartz rock ( $$ {\text{SiO}}_{2} $$ ). To investigate the effect of the electrical resistance and porosity on the quartz recovery rate, semicoke and metallurgical coke were separately tested in ferrosilicon arc furnaces. The product was quantitatively and qualitatively studied. The results showed that the higher electrical resistance and porosity of semicoke, in comparison with metallurgical coke, increased the efficiency of silicon recovery and also reduced the electrical energy consumption. The furnace efficiency when using semicoke and metallurgical coke was 90.8% and 80.5%, respectively.

Interfacial Behavior of Anionic/Cationic Flotation Collectors in Mixed Aqueous Solutions and Their Effect on Flotation Recovery of Quartz

AbstractIn this study, the effects of anionic/cationic collector mixtures on surface tension (γ) were investigated as a function of pH using the pendant drop method. For the tests, long‐chain tallow amine and petroleum sulfonate, which are the most common anionic and cationic flotation collectors, were used individually and as binary mixtures with different mixing ratios. The results show that pH of the solution had crucial effects on surface tension values of the amine whose species distribution varied with pH but not on petroleum sulfonate that is found in the ionized form over the entire pH range. In the case of binary anionic/cationic collector mixtures, the minimum surface tension values were obtained under highly acidic pH conditions with a mixing ratio of 1:3, while the collector mixtures with 3:1 and 1:1 mixing ratios displayed similar surface tension values at all pH values. For all binary‐collector mixtures with different mixing ratios, the surface tension values were found to be higher than those of single‐collector solutions with equal collector concentrations. In the case of microflotation tests, the flotation recoveries of quartz in the presence of the binary anionic/cationic collector mixtures dropped more than 25% when compared with the results in the presence of single‐collector solutions having equal collector concentrations.

On the role of nanobubbles in particle–bubble adhesion for the flotation of quartz and apatitic minerals

This work evaluated the influence of nanobubbles (150–200 nm, mean diameter) on the visual adhesion of microbubbles (70 μm mean diameter) and macrobubbles (1 mm mean diameter) onto selected mineral particles (quartz and apatite) and on the flotation of both minerals, at bench scale. The adhesion of bubbles to high purity grains of quartz and apatite was monitored using a specially designed photographic technique. The results showed that the highest adhesion of bubbles onto the mineral grains occurred only after “conditioning” with nanobubbles. The nanobubbles appear to adhere to hydrophobic surfaces and confined to the rough surfaces of the grains, probably due to the dissipation of the free surface energy of the solids. As a result, the nanobubbles appear to serve as nuclei for enhanced adhesion of micro and/or macrobubbles, assisting the flotation of both minerals. In the case of quartz (D50 = 290 μm), the recovery increase was about 23% compared to a standard test of flotation with macrobubbles only. Furthermore, flotation kinetics was rapid and quartz recovery, at the first min, was double that obtained in the absence of nanobubbles. In the case of a fine apatitic ore (35% < 37 μm particles), best results were obtained with a combination of nano, micro and macrobubbles, with a 500–1000 g t−1 saponified soybean oil collector and a 300–600 g t−1 gelatinized corn starch depressant of iron bearing minerals. The P2O5 recoveries increased about 9% compared to flotation with macrobubbles only, and separation also occurred at a higher rate. The total recovered phosphate (4 min standard test) was obtained in the first 1.5 min, after conditioning with nanobubbles, followed by injection of and microbubbles. Results validated the reported high potential for nanobubbles in “surface conditioning”, the first stage of mineral flotation and were explained in terms of the solution and interfacial phenomena involved.

Sorghum starch as depressant in mineral flotation: part 2 – flotation tests

In order to find a feasible replacement for cornstarch, the flour and starch of a graniferous variety of sorghum was tested as a depressant of hematite and quartz in a cationic microflotation in a modified Hallimond tube, using an ether amine as collector. Hematite and quartz samples from the Brazilian Iron Quadrangle were used in the flotation tests. The mineral samples were characterized by XRF, and SEM/EDS. Zeta potential measurements were performed in the pH range from 3.5 to 12.5. A commercial cornstarch was used as the depressant benchmark. Four depressants dosages and pH values were tested. A statistical test was used to verify the pH, dosage, and starch type influence on the minerals recoveries. At pH 10.5, the lowest average hematite recovery using sorghum starch was 7.27±1.22% for a dosage of 40mg/L, 13.24% lower than the value achieved for cornstarch. The results indicated that sorghum starch has a stronger depressant action on hematite than cornstarch. Quartz recovery was deeply influenced by the presence of cornstarch. Dosages below 40mg/L of sorghum starch recovered more quartz than cornstarch in all tested pH values. At pH 9 and dosage of 5mg/L, sorghum starch recovered 387% more quartz than cornstarch. The ANOVA test showed that pH, dosage, and starch type had significant impact on hematite and quartz recovery. The results suggest that sorghum has a great potential to replace corn as default depressant in iron ore flotation.

An evaluation of hydroxamate collectors for malachite flotation

Abstract Copper oxide minerals, such as malachite, do not often respond well to traditional copper sulphide collectors, and require alternative flotation schemes. Hydroxamic acid collectors have been suggested as a means to directly float malachite; however, there is limited information on the effect of reagent structure on the performance of these collectors. This paper investigated the effect of five alkyl hydroxamates and two aromatic hydroxamates on the flotation of a synthetic ore composed of pure, fully liberated, malachite and quartz. Zeta potential measurements were used to aid in understanding reagent adsorption onto the surface of the two minerals. The collectors were then evaluated using bench scale flotation results. While zeta potential measurements suggested that all the collectors investigated selectively adsorb onto the surface of malachite, only benzohydroxamic acid and C8 alkyl hydroxamates were effective collectors in the flotation of malachite. Benzohydroxamic acid was the most selective; however, significantly lower dosages of C8 alkyl hydroxamates were required to obtain similar malachite recoveries, with minimal increases in quartz recovery. Benzo- and octylhydroxamic acid were further examined for the flotation of fine (−38 μm) particles. For fine particle flotation experiments the effect of temperature was also investigated as a means to improve the flotation performance.

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.

Effects of fine–coarse particles interaction on flotation separation and interaction energy calculation

ABSTRACTThe particle interaction behavior is important in flotation process, and the interaction energy calculation is helpful for evaluating this behavior. This study investigates and compares the floatability of magnesite, dolomite, and quartz in single mineral flotation and artificial mixture flotation with dodecylamine (DDA) as collector. The results showed that while the pH, dissolved ions, and competitive adsorption had a minor influence on their floatability, fine magnesite and dolomite largely decreased the recovery of quartz. Scanning electron microscope (SEM) analysis on the flotation products demonstrated severe masking of fine particles on the surface of quartz. The extended-DLVO (Derjaguin–Landau–Verwey–Overbeek) theory was applied to calculate the interaction energy between the mineral particles, and the results showed that the interaction force between magnesite and quartz and between dolomite and quartz was attractive; therefore, fine magnesite and dolomite particles were easily masked on the surface of quartz. The calculation results agree with the experiment results and explain the mechanism of particles’ interaction and the reasons for the differences in single mineral flotation and artificially mixed minerals flotation.

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.

Depressing effect of fine hydrophilic particles on magnesite reverse flotation

The influence of fine particles on the flotation separation of minerals is becoming increasingly important as new, fine grained deposits are exploited. Fine particles float poorly and less selectively under normal flotation conditions, having detrimental effects on recovery of other minerals. The reasons of this interacting effect are complex, which may be entrainment, pH variation, dissolved ions from mineral surfaces, aggregation/dispersion and coating behavior of particles or even the competitive adsorption effect. In this study, the influence of fine magnesite and dolomite on the flotation of quartz was investigated. It was found that at pH=9.2–9.5 and with DDA dosage of 8.6×10−4, the recovery of coarse (−100+65μm) quartz was reduced dramatically from 96.66% to 37.15% when the content of quartz was 5% in the flotation with fine (−5μm) magnesite, and when the content of fine dolomite was increased from 2.5% to 20%, the recovery of coarse quartz was reduced from 91.20% to 75.08%. To examine the reasons, zeta potential, zero point of charge and contact angles of magnesite, dolomite and quartz were measured in the absence and presence of dodecylamine (DDA). The interaction energies between particles were then calculated. Results showed that the aggregation behavior of mineral particles was likely to be the reason. Interaction energy calculated based on Extended-DLVO (Derjaguin–Landau–Verwey–Overbeek) theory predicted that in DDA surfactant solution, the interaction forces between magnesite and quartz, dolomite and quartz were attractive, between dolomite and magnesite was repulsive. The experimental results are in excellent agreement with the theoretically predicted results. The aggregation caused by interacting behavior explains the depressing effect of fine hydrophilic particles on magnesite reverse flotation.

A Method of Calculating the Interaction Energy between Particles in Minerals Flotation

Extended-DLVO (Derjaguin-Landau-Verwey-Overbeek) theory is applied to calculating the interaction energy between particles in flotation process in the paper. This study investigates and compares the floatability of magnesite, dolomite, serpentine, and quartz in single mineral flotation and artificial mixture flotation with DDA as collector. The results showed that when the pH, dissolved ions, and competitive adsorption had a minor influence on their floatability, fine magnesite and dolomite largely decreased the recovery of quartz. SEM analysis on the flotation products demonstrated severe masking of fine particles on the surface of quartz. The Extended-DLVO theory was applied to calculate the interaction energy between the minerals, and the results showed that the interaction forces between magnesite and quartz, serpentine and quartz, and dolomite and quartz were attractive; therefore, fine magnesite, serpentine, and dolomite particles are easily masked on the surface of quartz. The calculation results agree with the experiment results and explain the mechanism of particles interaction and the reasons for the inconsistency in single mineral flotation and actual ore flotation. The particles interaction behavior is important in flotation process, and the interaction energy calculation is helpful for evaluating this behavior.

Flotation and adsorption of a new collector α-Bromodecanoic acid on quartz surface

A new type collector α-Bromodecanoic acid (CH3(CH2)7CHBrCOOH, α-BDA) was synthesized by solvent-free method (Hell–Volhard–Zelinski reaction) in laboratory for the flotation of quartz mineral at a relatively low temperature of 16°C. The adsorption mechanism of α-BDA collector on quartz mineral surface was established by zeta potential measurements, contact angle measurements, Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS), in conjunction with the results of quartz micro-flotation tests. The flotation results showed that the activator Ca(II) functioned as an indispensable and crucial factor on the recovery of pure quartz. When the quartz was floated with α-BDA alone at strong alkaline conditions (pH⩾11.50), the recovery rate reached to only 11.9%. However, when using the activator Ca(II) at a concentration of 4×10−4mol/L, the collector exhibited an excellent performance, where about 99.5% of the quartz had been floated at or above pH value 11.50 at 16°C. The study revealed that the α-BDA collector had adsorbed on the surface of pure quartz in the forms of electrostatic interaction, hydrogen bonding and chemical adsorption based on the results of zeta potential measurements, contact angle measurements, FT-IR spectra, and XPS.

Investigation of quartz flotation from decarburized vanadium bearing coal

Ether diamine (Fm 2835-2L) was used as a collector for flotation of quartz. It allows flotation of quartz from mica and calcite. The adsorption mechanism of Fm 2835-2L on quartz was investigated by flotation tests, zeta-potential measurements and infra-red (FTIR) spectra measurements. Results show that Fm 2835-2L adsorbs on the quartz surface in physical adsorption with no new products, changing its zeta potentials, and increasing its hydrophobicity. The effect of calcium ions on flotation of quartz was investigated by flotation tests and zeta-potential measurements. Results show that under neutral or weakly acidic conditions calcium cation can adsorb onto the surfaces of quartz, increase the zeta potential of quartz particles, which in turn causes weaker aggregation of quartz particles and lower flotation recovery of quartz. Under the alkaline conditions the hydrolytic components of calcium are also adsorbed on the quartz surface and increase the zeta potential of quartz particles, which causes stronger aggregation of quartz particles and higher flotation recovery of quartz. However, the hydrolytic components such as CaOH + , Ca(OH)2(aq) and Ca(OH)2(s) were not formed in significant amounts in the best flotation tests.

Use of the ionic liquid-tricaprylmethyl ammonium salicylate (TOMAS) as a flotation collector of quartz

Tricaprylmethyl ammonium salicylate (TOMAS), an ionic liquid has been employed as a collector for the flotation of quartz. The sign reversal of zeta potential of quartz from negative to positive values and increase in contact angle from 80 to 700 by the addition of TOMAS have substantiated the interaction of TOMAS with the quartz surface. The change in morphology as indicated in SEM and two peaks at 2933 and 2857cm−1 owing to the vibrations of CH2 and CH3 as seen in FTIR spectra support the adsorption of the reagent on quartz. The N(1s) peak as observed in the XPS spectra of the quartz treated with TOMAS, and the curve fitting data of C(1s) corroborate the reagent-mineral interaction. A comparative study of adsorption of DDA and TOMAS using classical molecular mechanics also suggests stronger adsorption of the latter on the hydroxylated quartz surface. Flotation studies of quartz at natural pH indicate ∼100% quartz recovery at a TOMAS concentration of 8*10−5M. Flotation of the natural occurring BHQ iron ore containing 38.7% Fe and 43.8% SiO2 concludes that a TOMAS concentration of 3.71*10−5M is sufficient to achieve 67.3% Fe with 66.6% iron recovery. TOMAS stands out as a better quartz collector, when compared with DDA.

Effect of Mn (II) on quartz flotation using dodecylamine as collector

Quartz is, in most cases, the major gangue mineral found in the manganese ore. Mn iron, dissolved from the surface of ore, will determine the interfacial properties of the particles and, thus, their flotation behavior. In this work, the effect of Mn2+ on quartz flotation was investigated through flotation tests. It was found that quartz can be depressed with Mn2+ and floated with dodecylamine in the pH region 7-8. In order to prove the validity of the findings, UV spectrophotometry, FTIR and SEM-EDS were carried out. UV spectrophotometry tests results show that Mn2+ can competitive adsorb with RNH3 (+) in the surface of quartz at acidic and neutral pH values. The FTIR measurements and SEM-EDS analysis indicate that Mn2+ forms precipitation and adsorbs on the negatively charged quartz surface, it induces quartz recovery dropping in alkaline pH. Furthermore, in the case of sodium hexametaphosphate (SH), sodium silicate or citric acid, the effects of Mn2+ were also studied. This depression in the given Mn2+ did not disappear. Citric acid is an appropriate modifier to separate quartz depressed by Mn2+ from other ores at pH 7.