Flotation Recovery Of Pyrite Research Articles

Flotation separation of pyrite and carbonate minerals from a carlin-type gold deposit in Guizhou by a new combined collector and its adsorption mechanism

Flotation is the most common method for effective separation of pyrite and carbonate minerals from Carlin-type gold deposits. The effect of conventional xanthate collector on flotation of a Carlin-type gold mine in Guizhou province is poor, and it can not effectively remove carbonate minerals. In this paper, butyl xanthoxanthate and benzohydroxamic acid (BHA) were used as a new combined collector for the flotation separation of a Carlintype gold mine in Guizhou Province. The flotation behavior of pyrite and its adsorption mechanism on pyrite surface were discussed in detail through pure mineral flotation test, actual ore flotation test, contact Angle test, infrared spectrum analysis and XPS analysis. The results showed that the collection capacity of butyl xanthoxime combined with benzohydroxamic acid was obviously stronger than that of BHA or butyl xanthoxime alone. The optimal ratio of pyrite flotation with combined collector is 3, and the recovery rate of pyrite flotation is 37%, which is higher than that of pyrite flotation recovery of 30.5% when benzohydroxamic acid is used alone and 28.5% when butyl xanthate is used alone. The contact Angle test, infrared spectrum and XPS analysis showed that the combined collector of butyl xanthate and benzohydroxamic acid (BHA) produced strong chemical adsorption on the surface of pyrite. Bha can increase the adsorption capacity of butyl xanthate on the surface of pyrite, which is conducive to the flotation recovery of pyrite.

Effect of D-arginine as a novel depressant on the flotation separation of chalcopyrite from pyrite at low alkalinity

Flotation separation of Cu–Fe sulfide minerals typically necessitate the addition of substantial quantities of lime to depress pyrite flotation. Because lime can harm the environment, there is an urgent need to develop novel environmentally friendly depressants that are non-toxic and biodegradable. In this study, we investigated an environmentally friendly pyrite depressant containing amino and carboxyl groups, namely D-arginine (DA). The effect of DA on the surface hydrophobicity of Cu–Fe sulfide minerals and thus collector adsorption was investigated by analyzing zeta potentials, adsorption capacities, and contact angles. Additionally, changes in the surface properties of the minerals induced by DA were examined using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and atomic force microscopy (AFM). Flotation tests revealed that 2 × 10–4 mol/L DA reduced the flotation recovery of pyrite to 9.96 % at low alkalinity while leaving chalcopyrite recovery unchanged. The results of mineral surface analysis indicated that DA exhibited significantly stronger adsorption on the pyrite surface than on the chalcopyrite surface. Furthermore, DA effectively reduced the adsorption of the collector on the surface of pyrite, thereby weakening pyrite floatability at low alkalinity. Therefore, DA is a promising alternative depressant for the flotation separation of chalcopyrite from pyrite.

Mixed Anionic/Cationic Collectors for Pyrite Flotation: An Experimental and Theoretical Study

ABSTRACT The presence of pyrite causes harmful environmental and metallurgical effects during the pyrometallurgical processes of metals. Hence, various processing methods should minimize the amount in the feed. Meanwhile, flotation is one of the most common methods due to the natural hydrophobic property of the pyrite surface. Based on this premise, this research focuses on the efficiency of pyrite flotation using mixed anionic/cationic collectors as one of the significant factors of flotation. This study is organized and performed in two laboratory and simulation sections. Lab-scale studies consider the kind of collector(s), collector(s) concentration, size, frother concentration, and pH as practical factors. Dodecyl amine (DDA), potassium amyl xanthate (PAX), and Sodium Isopropyl Xanthate (SIPX) are three types of collectors examined in the single and mixed forms for pyrite flotation. In the simulation part, adsorption of a single form and mixed forms of collectors on the pyrite (001) surface and its effects on the wetting property of the surface is investigated using the molecular dynamics approach. In sum, the results of this study show that, although pyrite has the favorable ability of flotation with anionic collectors from the xanthate family (PAX and SIPX) due to its natural hydrophobic feature, the presence of a cationic collector (DDA) significantly enhances its flotation performance so that a 1:1 mixture of DDA and PAX with a concentration of 15 for each collector, at pH 7, and the presence of an A65 as frother (30 ), increases the flotation recovery of pyrite by more than 95%.

Effect of regulating dissolved oxygen concentration in pulp with aerated gas on pyrite flotation

Moderate oxidation is beneficial to the flotation of sulfide ores, but the exact dissolved oxygen (DO) concentration suitable for flotation is still unclear. In this work, a self–made vacuum aeration flotation equipment was designed and assembled to accurately control the DO concentration in pulp by adjusting the relative proportion of O2/N2 during aeration, and the effect of DO concentration on the floatability and surface properties of pyrite as well as the interaction between pyrite and xanthate was studied. Microflotation experiments, contact angle, time–of–flight secondary ion mass spectrometry, X–ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, electrochemical and localized electrochemical impedance spectroscopy measurements were conducted in this investigation. The results showed that the flotation recovery of pyrite could be remarkably affected by DO concentration in pulp; it increased first and then decreased with the increase of DO concentration; an optimal DO concentration (DO = 3.3 mg/L) was helpful for pyrite flotation recovery; both the formation of dixanthogen and the avoidance of excessive iron oxide/hydroxide formed on pyrite surface were the key to improve the pyrite recovery. This research is expected to be applied in optimizing the flotation separation by DO-pH combined detection and regulation, strengthening the green flotation of sulfide ore with low collectors, and the design and manufacture of new closed and efficient sulfide ore flotation equipment.

Tailored pH-triggered surfactant for stepwise separation of a three-component mineral system

Stepwise separation of multi-species with a single type of chemical additives (such as surfactants) is an auspicious but challenging issue in many engineering processes as one surfactant usually lacks the ability to interact with different components. One promising strategy is to develop an environment-responsive surfactant, which possesses various functional groups to anchor target constituents under different environmental conditions. In this work, we have prepared a pH-responsive surfactant (2-(benzylthio)-acetohydroxamic acid, BTHA) possessing two pH-switchable groups (i.e., thioether and hydroxamate) that can selectively interact with different target substances, thus enabling stepwise and efficient separation of a three-component mineral system. The single in-house synthesized BTHA is successfully applied to the sequential separation of pyrite, diaspore, and kaolinite from high-sulfur bauxite by simply tuning the solution pH. Specifically, under the acidic condition (pH 6.0), the hydroxamate group of BTHA is deactivated, thus only the thioether groups can directionally interact with pyrite and enable the selective flotation recovery of pyrite to 85.9%. When the solution pH is subsequently increased to 8.0, the active hydroxamate group of BTHA can tightly chelate with diaspore and result in its efficient separation from kaolinite. The bifunctional surfactant exhibits strong and selective interactions with target substrates via pH modulation, allowing the adsorption selectivity and efficient stepwise separation, which provides an innovative paradigm for the development of novel surfactants with diverse applications in the mineral, metallurgical, chemical, and renewables recycling industry.

Experimental and theoretical study of the effect of pH level on the surface properties and floatability of pyrite

This study concentrated on a thorough surface investigation to ascertain how pH affected the surface characteristics and floatability of pyrite. To assess the impact of pH on the adsorption of collector on the surface of pyrite, a special computational model was also created. Although it varied at various medication dosages, the flotation recovery of pyrite indicated a reduction with rising pH, according to the results of the flotation studies. Contact angle and other tests revealed that as pH rose, the surface of pyrite slightly oxidized to expose corrosion pits, hydrophilic oxidation products (Fe(OH)3, SO42-, etc.) gradually deposited on the surface, the surface hydrophilicity of pyrite increased rapidly, and the adsorption of xanthate was inhibited. In accordance with the experiments, the adsorption strength trend of xanthate on the surface of pyrite was supported by the findings of DFT calculations. As pH rose, the interaction distance between xanthate and surface gradually widened and the force gradually decreased. Additionally, the hydroxylation of surface became increasingly significant and its oxidation trend sharpened with increasing pH. The findings of this investigation open the door for future research on related sulphide minerals by illuminating the variations in surface properties of pyrite at various pH levels and its interaction with xanthate.

Depression of Pyrite in Seawater Flotation by Guar Gum

The application of guar gum for pyrite depression in seawater flotation was assessed through microflotation tests, Focused Beam Reflectance Measurements (FBRM), and Particle Vision Measurements (PVM). Potassium amyl xanthate (PAX) and methyl isobutyl carbinol (MIBC) were used as collector and frother, respectively. Chemical species on the pyrite surface were characterized by Fourier-transform infrared spectroscopy (FTIR) spectroscopy. The microflotation tests were performed at pH 8, which is the pH at the copper sulfide processing plants that operate with seawater. Pyrite flotation recovery was correlated with FBRM and PVM characterization to delineate the pyrite depression mechanisms by the guar gum. The high flotation recovery of pyrite with PAX was significantly lowered by guar gum, indicating that this polysaccharide could be used as an effective depressant in flotation with sea water. FTIR analysis showed that PAX and guar gum co-adsorbed on the pyrite surface, but the highly hydrophilic nature of the guar gum embedded the hydrophobicity due to the PAX. FBRM and PVM revealed that the guar gum promoted the formation of flocs whose size depended on the addition of guar gum and PAX. It is proposed that the highest pyrite depression occurred not only because of the hydrophilicity induced by the guar gum, but also due to the formation of large flocs, which could not be transported by the bubbles to the froth phase. Furthermore, it is shown that an overdose of guar gum hindered the depression effect due to redispersion of the flocs.

Mechanism of sodium sulfide on flotation of cyanide-depressed pyrite

Abstract The mechanism of sodium sulfide (Na2S) on the flotation of cyanide-depressed pyrite using potassium amyl xanthate (PAX) as collector was investigated by flotation test and electrochemical measurements. The flotation results show that both PAX and Na2S can promote the flotation recovery of cyanide-depressed pyrite and their combination can further improve the pyrite flotation recovery. Electrochemical measurements show that PAX and Na2S interacted with cyanide-depressed pyrite through different mechanisms. PAX competed with cyanide and was adsorbed on the pyrite surface in the form of dixanthogen, thus enhancing the hydrophobicity and flotation of cyanide-depressed pyrite. Unlike PAX, Na2S rendered the pyrite surface hydrophobic through the reduction of ferricyanide species and the formation of elemental sulfur S0 and polysulfide. The combined application of PAX and Na2S induced superior pyrite flotation recovery because of a synergistic effect between PAX and Na2S.

Effect of high voltage pulse treatment on the surface chemistry and floatability of chalcopyrite and pyrite

The effect of high voltage pulse (HVP) treatment on the surface chemistry and flotation behaviour of chalcopyrite and pyrite were investigated using single mineral. The results indicated that the effect of HVP treatment on pyrite was more significant than chalcopyrite, both in terms of size reduction degree and flotation behaviour. Despite the stronger resistance to mechanical breakage than chalcopyrite, the proportion of −0.053 mm product of pyrite was higher than chalcopyrite for 12.2 per cent in average after HVP treatment of different pulse numbers. The flotation recovery of chalcopyrite was only slightly reduced after HVP treatment of 130 pulse discharges. However, under the same test conditions, the flotation recovery of pyrite was reduced by 64.1 per cent in average. The flotation behaviour of the two single minerals were in agreement with their surface oxidation behaviour in HVP treatment. XPS analysis and EDTA extraction suggested that chalcopyrite surface had only partially oxidized by HVP treatment; whereas pyrite was deeply oxidized with a large amount of S element converted to be sulphate radicals. The relative permittivity of pyrite, chalcopyrite and water was 33.5, 78.1 and 80 respectively, which led to a ratio of electrical field strength inside pyrite, chalcopyrite and water theoretically being 2.39:1.02:1. As a result, pyrite particles had stronger capability to attract electrical breakdown channel than chalcopyrite, and subjected to more severe size reduction and surface oxidation under the same conditions. On the other hand, the slight surface oxidation of chalcopyrite particles was hypothesized to be caused by the active species (OH, H2O2, etc.) formed during pulse discharge.

Effects of particle size and ferric hydroxo complex produced by different grinding media on the flotation kinetics of pyrite

Flotation kinetics is an excellent tool used to evaluate flotation performance, which is controlled by several factors, such as the particle size, bubble size, and surface property. In this study, we investigated the effects of particle size and ferric hydroxo complex produced by grinding with CB and CIB media on the flotation kinetics of pyrite using Python statistical analysis software and Origin software based on five flotation kinetic models. The results showed that the pyrite particles produced when CB was used as the grinding medium exhibited better cumulative experimental recovery owing to a lower formation of ferric hydroxo complexes. In the case of grinding with CB medium, the first-order flotation kinetic model (ε = ε∞(1 − e−kt)) provided the best fit for the experimental data, whereas the first-order and second-order flotation kinetic model are considered the best in the case of grinding with the CIB medium depending on the experimental conditions. In addition, the particle size and the ferric hydroxo complex were found to be the determining factors of the flotation rate constant (k) and cumulative ultimate recovery (ɛ∞), respectively, in both cases. The intermediate sizes of 10 to 120 μm were found to be the optimal particle sizes for achieving a higher pyrite flotation rate. Less quantity of ferric hydroxo complexes formed on the surface of the pyrite particles, resulting in a higher ɛ∞. The presence of ferric ions inhibited the pyrite flotation recovery and its flotation rate once the pulp pH was sufficient to cause complete precipitation of the ferric hydroxo complex.

Desulphurization of coals of different ranks in the presence of slimes by reverse flotation

In this paper, the flotation separation of pyrite from sub-bituminous and meta-bituminous coals in the presence of slimes was investigated. The sub-bituminous coal and the meta-bituminous coal have significant differences in their surface properties compared with pyrite. The flotation experiments were performed in the presence of potassium amyl xanthate (PAX) collector. The adsorption of PAX on pyrite was significant while that on the coal surfaces was negligible. The recovery of pyrite from sub-bituminous coal increased by 55% when the concentration of PAX increased from 1×10−4mol/L to 5×10−4mol/L. Similarly, pyrite recovery from the meta-bituminous coal increased by up to 60% for the coarser size fraction upon increasing PAX concentration from 1×10−4mol/L to 5×10−4mol/L. Before the de-sliming process, the flotation recovery of pyrite increased with decreasing coal particle size whereas the opposite is true for pyrite grade. Desliming reduced the adsorption amount of PAX on pyrite by more than 50% because of the removal of fine particles that would otherwise be available for adsorption. Desulphurization of fine coal appears to be challenging probably due to the increased entrainment of fine coal particles during pyrite flotation. The de-sliming process increased pyrite grade by >20% for the meta-bituminous coal and by 10% for the sub-bituminous coal. The results suggest that excessive collector consumption by fine particles and slimes, and entrainment are the main challenges in separating pyrite from coal particles.

Influence of clays on the slurry rheology and flotation of a pyritic gold ore

The presence of clay minerals in ores has been known to adversely affect the flotation performance. This work investigated the influence of kaolin and bentonite clays on the flotation of gold-bearing pyrite in the gold ore. The changes in rheological properties of the flotation pulp under normal operating conditions were also studied with the additions of kaolin and bentonite clays at various solid concentrations. The zeta potential measurements also were carried out to understand the mechanism of adsorption of potential determining ions. It was found that bentonite clay reduced the pyrite recovery, and modified the pulp rheology more than kaolin. The addition of Ca2+ ions to the pulp containing bentonite improved the pyrite flotation recovery by its ability to modify the rheological characteristics. It is consistent with the published literature that Ca2+ ions suppressed the swelling properties of bentonite, and altered the surface charge properties of bentonite clay particles. Additionally, the rheological characteristics such as the flow index and the consistency index affected the flotation performance as the former indicates the extent of movement of bubbles and particles within flotation pulp. This suggests the possibility of using the rheological measures to monitor the changes in the flotation performance in routine plant operations.

The separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding

In this study, the differences between the separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding were investigated. In the rougher flotation prior to regrinding, high chalcopyrite and chalcocite recovery were obtained in conjunction with high pyrite flotation recovery due to the activation of pyrite by copper ions during primary grinding. The rougher flotation concentrate was reground in a rod mill before cleaner flotation. It was found that chalcopyrite and chalcocite exhibited different flotation behavior and also affected pyrite flotation differently in cleaner flotation. The mechanism underpinning these phenomena was investigated by a range of techniques including the polarization of mineral electrodes, X-ray photoelectron spectroscopy (XPS) analyses and ethylene diamine tetraacetic acid (EDTA) extraction. It was found that the flotation behavior of both copper minerals and their effect on pyrite flotation after regrinding were governed by their electrochemical activities and galvanic coupling with pyrite.

The solution chemistry of carbonate and implications for pyrite flotation

The solution chemistry of carbonate and implications for pyrite flotation in the presence of lizardite have been investigated. The results show that lizardite causes problems in the flotation of pyrite, by adhering to the pyrite particles. Addition of various reagents which can produce carbonate has been found to improve pyrite recovery during flotation. The solution chemistry of carbonate indicated that carbonate mainly exists in the form of CO32- ions in the pH range that carbonate can restore pyrite flotation recovery. When the reagent producing the carbonate ion is able to provide it at a higher concentration, the pyrite flotation performance is improved.

Solution Chemistry of Sodium Silicate and Implications for Pyrite Flotation

The solution chemistry of sodium silicate and implications for pyrite flotation have been studied. In addition to flotation and sedimentation tests, electrophoresis, inductively coupled plasma (ICP) tests, and X-ray photoelectron spectroscopy (XPS) have been used. The flotation and sedimentation results show that lizardite causes problems in the flotation of pyrite by adhering to the pyrite particles. Addition of the sodium silicate could make the mixed sample of pyrite and lizardite more disperse in the alkaline condition and significantly reduce the adverse effect of lizardite on the flotation of pyrite. ICP tests and XPS analysises show that sodium silicate can adsorb onto the lizardite surface and change the surface characteristic of lizardite. Sodium silicate mainly exists in the form of SiO(OH)3– in the pH range that sodium silicate can restore pyrite flotation recovery. The adsorption of SiO(OH)3– ions at the lizardite/solution interface overcompensates the positive charge on the lizardite particle and its ζ potential is rendered negative. The total interaction energy between lizardite and pyrite is changed from attractive energy to repulsive energy in the presence of sodium silicate, according to the calculation of the Derjaguin–Landau–Verwey–Overbeek theory.

The effect of lizardite surface characteristics on pyrite flotation

The effect of lizardite surface characteristics on pyrite flotation has been investigated through flotation tests, adsorption tests, zeta potential measurements, FTIR study, X-ray photoelectron spectroscopy (XPS) and sedimentation tests. The flotation results show that at pH value 9, where flotation of nickel sulfide ores is routinely performed, two kinds of lizardite samples (native lizardite and leached lizardite) have different effects on the flotation of pyrite. The native lizardite adheres to the surface of pyrite and reduces pyrite flotation recovery while the leached lizardite does not interfere with pyrite flotation. Infrared analyses and XPS tests illustrate that acid leaching changed the surface characteristics of lizardite mineral and the leached lizardite has less magnesium on its surface. It has been determined that the electro-kinetic behavior of lizardite aqueous suspensions is mainly a function of the Mg/Si atomic ratio on lizardite surface. So, the low isoelectric point observed in the leached sample has been linked to values of this ratio lower than that of the native lizardite.

Surface study of the effect of sulphite ions on copper-activated pyrite pre-treated with xanthate

X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry have been used to determine the specific effect of sulphite ions on the surface chemistry of copper-activated pyrite pre-treated with isobutyl xanthate in flotation experiments with nitrogen and air purging at pH 7. The results from these spectroscopic techniques illustrate that sulphite ions affect the surface chemistry of pyrite similarly whether nitrogen or air purged. It was found that sulphite ions interact with adsorbed collector species, as well as with the pyrite surface itself. A reduction in the adsorbed collector concentration and a commensurate increase in surface hydrophilicity explain the low flotation recovery of pyrite in the presence of sulphite. As expected, this effect was more pronounced in the flotation experiments with air purging.

加温による黄鉄鉱浮選の抑制効果

The depressing effect of raising pulp temperature on pyrite flotation have been investigated by using diethyl dithiophosphate (ethyl aerofloat, E. A. F.) as a collector. The mechanism of depression have been studied in terms of collector adsorption and changes in concentration of sulfate, hydroxide and iron ions in pulp during conditioning, and the surface products after conditioning identified by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and X-ray photo-electron spectroscopy (XPS).The results obtained are as follows:The flotation recovery of pyrite at pH 6 was only slightly decreased by raising pulp temperature from25°C to °C in the presence of large amounts of collector, but it was significantly depressed in moderate collector addition of the order of 200-300 g/t.There was no difference between collector adsorption at 25 °C and that at 60°C in the collector addition less than 500 g/t. Accordingly, the depression of pyrite by raising pulp temperature can not be explained by the decrease of collector adsorption.From the changes of the concentration of sulfate, hydroxide and iron ions before and after conditioning at 25°C or 60°C, it was suggested that basic iron sulfate was precipitated on pyrite surface during conditioning at either pulp temperature, but the amount precipitated at 60 t was much larger than that at 25°C, because the oxidation reaction of pyrite surface took place at 60°.The existence of sulfate on the pyrite surface after conditioning at 60 t was detected by DRIFTS and XPS.From the above experimental results, it is concluded that pyrite depression by raising pulp temperature is mainly attributed to the formation of hydrophilic basic iron sulfate which offsets the hydrophobization effect with collector adsorption.