Flotation Separation Of Chalcopyrite Research Articles

Synthesis of S-Allyl-O, O′-Dibutyl Phosphorodithioate and Its Adsorption Mechanism on Chalcopyrite Surface

The demand for non-ferrous copper metals has increased dramatically with the development of the global economy; accordingly, some refractory copper sulfide ores with low grade and their associated minerals are beginning to be utilized, making the flotation separation of copper concentrates exceptionally difficult, especially the separation of chalcopyrite and pyrite. In this paper, S-allyl-O, O′-dibutyl phosphorodithioate (ADTP) was synthesized by a one-pot method and used as a chalcopyrite collector in the flotation separation of chalcopyrite and pyrite. Flotation experiments results have shown that ADTP exhibits better selectivity and greater collecting power for chalcopyrite under neutral or weak base conditions. The 95% recovery of chalcopyrite can be achieved at pH 8.0 and 8.0 mg/L ADTP. From the analysis results of the contact angle, the SEM-EDS spectrogram, and elemental mapping, it was found that ADTP adsorbed uniformly on a chalcopyrite surface and made a significant contribution to the hydrophobicity of the surface. Confirmed by FTIR and XPS analysis, ADTP was able to form P–S–Cu bonds on a chalcopyrite surface, proving that it was adsorbed on the chalcopyrite surface in the form of chemisorption.

Flotation separation of chalcopyrite from galena based on selective adsorption of pyrogallic acid: Experiments and MD simulations

Novel eco-friendly organic depressants with high selectivity are attracting ever-growing interests. The selective inhibition effect of pyrogallic acid (PA) on galena in chalcopyrite flotation was investigated in this study. Flotation trials showed that PA markedly depressed galena with only a small effect on chalcopyrite, which contributed to the separation of chalcopyrite and galena by flotation after adding a low dosage of PA. Surface hydrophobicity tests suggested that PA strongly adsorbed on galena but not on chalcopyrite, which attenuated the adsorption activity of collector on galena, thus rendering galena highly hydrophilic. Conversely, chalcopyrite still retained favorable floatability. These findings were corroborated by the results obtained from infrared and surface adsorption measurements. Results of time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy measurements also validated the strong adsorption of PA on galena. This behavior promoted the generation of other hydrophilic species on galena. In addition, molecular dynamic simulations demonstrated that PA tended to adsorb on galena, and water molecules accumulated on galena following PA adsorption, which would decrease the floatability of galena.

Flotation separation of chalcopyrite from pyrite and sphalerite using a novel collector: An experimental and mechanism investigation

In this paper, a new collector, named O-isobutyl-N-allyl thionocarbamate (IBATC), was synthesized, and the structure was characterized by Fourier Transform Infrared Spectrometer (FTIR) and 1H NMR, 13C NMR analysis. The collection performance of IBATC was evaluated by flotation tests and interaction mechanism was investigated by means of adsorption amount, zeta potential measurements, FTIR, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation. The flotation tests results proved that IBATC was inclined to collect chalcopyrite compared with pyrite and sphalerite. Especially in the pH range of 9.5–10 and IBATC concentrate of 30–40 mg/L, the recovery of chalcopyrite exhibited more than 80 %. The adsorption amount and zeta potential measurements showed that IBATC had a greater orientation to chalcopyrite. FTIR and XPS analysis demonstrated IBATC chemically adsorbed on chalcopyrite surface, whereas physically adsorbed on pyrite and sphalerite. Further, DFT calculation of the interaction between IBATC and chalcopyrite proved that S atom of IBATC donated electrons to Cu sites on chalcopyrite surface and the adsorption energy was −19.45 kcal/mol, referring to an exothermic reaction. As a result, IBATC showed great capacity for the separation flotation of chalcopyrite, pyrite and sphalerite.

Flotation separation of chalcopyrite from molybdenite with sodium thioglycolate: Mechanistic insights from experiments and MD simulations

The pivotal roles of Cu and Mo in industrial applications accentuate the importance of effectively separating and recovering chalcopyrite and molybdenite. They commonly exist together in natural environments, necessitating their segregation prior to engaging in smelting processes. The separation is mainly accomplished through flotation. The inadequate comprehension of the mechanisms of thiol depressants, commonly used in the separation of chalcopyrite and molybdenite, poses challenges to both resource recovery and the development of depressants. Based on the bulk flotation practice of copper-molybdenum sulfide minerals, this study investigated the separation effect and mechanism of sodium thioglycolate (STG) on xanthate-treated chalcopyrite and molybdenite. Flotation and contact angle tests validate that STG enhances the hydrophilicity of chalcopyrite surfaces, leading to an 83.79% flotation separation efficiency for molybdenite. Various methodologies were employed to explore the mechanism of the depressant, encompassing open-circuit potential measurements, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, infrared and ultraviolet spectroscopy, time-of-flight secondary ion mass spectrometry, classical molecular dynamics and ab initio molecular dynamics simulations. The stable adsorption layer of STG is established by the interaction of thiol groups from STG with Cu and Fe sites on the chalcopyrite surface, resulting in the formation of Cu(I)-S and Fe(III)-S structures. The adsorption density of STG layer on the chalcopyrite surface is four times greater than that on molybdenite. Additionally, following the adsorption of STG, the previously adsorbed xanthate chalcopyrite surface is desorbed with an efficiency of 65.88%. These findings contribute to the elucidation of the mechanistic understanding of thiol-containing depressants in the flotation separation process of copper-molybdenum sulfide minerals and establish a basis for the prospective advancement of mineral processing reagents.

Effect of polyaspartic acid as an environmental-friendly depressant on flotation separation of chalcopyrite from arsenopyrite

The selection of environmental-friendly and high-efficiency depressants is a major research priority for removing arsenic from copper concentrates. The polyaspartic acid (PASP, (C4H6O3N) n) was used for the selective separation of chalcopyrite from arsenopyrite to explore the depression mechanism of PASP using micro-flotation experiments, contact angle measurements, zeta potential measurements, fourier transform infrared spectroscopy (FT-IR), local electrochemical impedance (LEIS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The flotation results showed that recovery of chalcopyrite reached up 90.18 %, while the recovery of arsenopyrite was only 23.48 %, when the PASP was added. The contact angle measurements and zeta potential measurements showed that PASP selectively adsorbed on the surface of arsenopyrite, but was not adsorbed on the surface of chalcopyrite. The FT-IR tests further confirmed that the adsorption was chemical adsorption. The LEIS tests revealed that the conductivity of arsenopyrite surface increased with the addition of PASP, while chalcopyrite was almost unaffected. The ToF-SIMS analyses illustrated that the arsenopyrite with Fe and As sites was reacted with —NH– in the structure of PASP to form stable complexes. Finally, the mechanism diagram was designed to provide insight into the adsorption mechanism of PASP on the surface of arsenopyrite and its selective inhibition of arsenopyrite.

The combination of calcium hypochlorite and fulvic acid as an efficient arsenopyrite depressant in Cu-As separation

In this work, fulvic acid (FA) was tested as a novel arsenopyrite depressant in the flotation separation of chalcopyrite from arsenopyrite with or without calcium hypochlorite (Ca(ClO)2). The flotation behaviors were investigated by single and artificial mixed mineral flotation tests. The depression mechanism of FA and Ca(ClO)2 on mineral surface was uncovered by electrochemical measurement, Zeta potential, contact angle, adsorption capacity, Raman, Fourier Transform Infrared spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). Flotation tests illustrated that FA had strong depression action on arsenopyrite but hardly influenced the flotation of chalcopyrite with or without Ca(ClO)2. Electrochemical measurement and Raman spectra results showed that the oxidation degree of arsenopyrite surface was higher than that of chalcopyrite. Zeta potential, FTIR and adsorption capacity results illustrated that FA preferred to adsorb on arsenopyrite surface than chalcopyrite surface, and the introduction of Ca(ClO)2 facilitated the adsorption of FA on arsenopyrite surface. XPS results indicated that Ca(ClO)2 promoted the oxidation of arsenopyrite surface to form more iron oxide products. In addition, FA strongly absorbed on arsenopyrite surface via the complexing between hydroxyl groups and Fe oxidized product to form Fe-OH species, preventing the adsorption of sodium isobutyl xanthate (SIBX) on arsenopyrite and rendering it hydrophilic. While FA weakly adsorbed on chalcopyrite surface, which could be substituted by SIBX and regain hydrophobicity.

Utilization of PMA-EDTC as a Novel Macromolecular Depressant for Galena in the Flotation Separation of Chalcopyrite

Utilization of PMA-EDTC as a Novel Macromolecular Depressant for Galena in the Flotation Separation of Chalcopyrite

Selective Separation of Chalcopyrite from Pyrite Using Sodium Humate: Flotation Behavior and Adsorption Mechanism.

Flotation separation of chalcopyrite from pyrite using lime or cyanides as depressants results in serious problems, such as the blockage of pipelines and environmental pollution. Eco-friendly organics are a future trend for beneficiation plants. In this research, the eco-friendly organic depressant sodium humate (SH) was chosen as a depressant to separate chalcopyrite from pyrite by flotation. The results indicated that SH could selectively depress pyrite owing to the oxidation species (FeOOH, Fe2(SO4)3) on its surface. The oxidation species were the adsorption sites for the COO- in the SH structure and impeded the subsequent collector potassium ethyl xanthate (KEX) adsorption. However, chalcopyrite was slightly oxidized with fewer oxidation species for SH adsorption, and KEX could be adsorbed and functioned effectively. This research suggested that SH could be an effective and eco-friendly depressant in chalcopyrite-pyrite flotation separation, which had potential use in the industry.

Selective separation of carrollite and chalcopyrite at low alkalinity with xanthan gum as a depressant

The flotation separation of chalcopyrite and carrollite, the two primary copper and cobalt minerals in sedimentary copper-cobalt ores, has been less studied. In this paper, the role of xanthan gum (XG) as a depressor in the flotation separation of chalcopyrite and carrollite by a series of flotation tests, adsorption amount tests, zeta potential measurements, and Furier-transform infrared spectroscopy (FTIR) analysis. The flotation tests showed that XG could selectively flotation separate the chalcopyrite and carrollite at low alkalinity. The results of reagents adsorption tests and zeta potential measurements illustrated that XG has a much stronger adsorption capacity on the surface of carrollite than chalcopyrite, inhibiting the subsequence adsorption of PBX on the carrollite surface. FTIR analysis further illustrated that XG is adsorbed on the carrollite surface by the combined action of hydrogen-bonded and carboxyl-metal complexes groups.

Novel application of depressant sodium mercaptoacetate in flotation separation of chalcopyrite and pyrite

The development of flotation reagents with high selectivity and strong depression ability is of great significance in the efficient enrichment of copper sulfide ores. In this work, a new depressant, sodium mercaptoacetate (SMA) has been explored for the flotation separation of chalcopyrite and pyrite, and the depression mechanism of SMA was studied by Fourier Transform Infrared spectrometer (FTIR), adsorption tests, local electrochemical impedance spectroscopy test (LEIS), Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). Micro-flotation tests showed that SMA strongly depresses pyrite in the pH range of 6–10. When the dosage of SMA is 2.5 × 10−5 mol/L, the dosage of SBX is 1 × 10−5 mol/L, and pH = 6.5, the concentrate with a Cu grade of 31.93% and chalcopyrite recovery of 85.97% can be obtained, in which the pyrite recovery was only 4.18%, respectively. The strong chemical adsorption between SMA and Fe atomic sites exposed on the surface of pyrite reduces the hydrophobicity of pyrite and hinders the adsorption of SBX. In comparison, SMA has less adsorption on the surface of chalcopyrite and hardly affects the further adsorption of SBX. It was shown that SMA could be used as an effective depressant for pyrite in the flotation separation of chalcopyrite and pyrite.

Flotation separation of chalcopyrite from pyrite using a novel O-n-butyl-N-isobutyl thionocarbamate as the selective collector

A novel thionocarbamate collector, O-n-butyl-N-isobutyl thionocarbamate (NBIB), was synthesized. The flotation test showed that NBIB has good selectivity under low alkali conditions. NBIB has a strong ability to collect chalcopyrite in the pH range of 6 − 11 though it is slightly affected by pH. The ability to collect pyrite is weak and decreases with increasing pH. The adsorption mechanism of NBIB was studied by adsorption measurements, UV–Vis spectroscopy scanning, contact angle measurements, zeta potential measurements, XPS and density functional theory (DFT) calculations. The results showed that the adsorption capacity of NBIB on the chalcopyrite surface is much larger than that on pyrite, and it is not affected by pH, which is consistent with the flotation test results. UV–Vis spectrum scanning showed that the interaction between NBIB and Cu2+ is stronger than that between NBIB and Fe2+. At pH = 9, the hydrophobicity of NBIB on the chalcopyrite surface is greater than that of pyrite. Zeta potential and XPS analysis showed that NBIB may have chemical adsorption on the chalcopyrite surface, but the interaction on the pyrite surface is very weak. DFT calculations further confirm that the bond atom of NBIB is the S atom of the C = S double bond, which has the conditions for forming chemical bonds with chalcopyrite.

Enhanced selective hydrophobicity performance at solid-liquid interface during separation of chalcopyrite from galena with 5-methyl isobutylxanthate-1,3,4-oxadiazole-2-thione

In order to improve the separation efficiency of copper and lead minerals, reduce the use of inhibitors, and further break the design bottleneck of the flotation collector, a novel compound with a di-minerophilic group was designed as a collector used for separating copper and lead minerals. In this study, novel oxadiazole-thione surfactants with or without a di-minerophilic group, including 5-methyl isobutylxanthate-1,3,4-oxadiazole-2-thione (MIXODT) and 5-heptyl-1,3,4-oxadiazole-2-thione (HpODT), were synthesized and introduced initially as collectors in flotation separation of chalcopyrite from galena. Micro-flotation indicated that MIXODT exhibited improved flotation ability and selectivity for chalcopyrite than HpODT. Meanwhile, DFT calculations also showed that the reactivity of MIXODT was higher than HpODT. The MIXODT's better selective adsorption behavior was characterized by wettability measurements, ζ-potential and UV spectra. The results of adsorption thermodynamic and kinetic experiments confirmed that MIXODT adsorption on chalcopyrite was an endothermic-spontaneous chemisorption process, with ΔH (change of enthalpy), ΔS (change of entropy), ΔG (change of free energy) and Ea (activation energy) values of 59.74 kJ·mol−1, 274.70 J·mol−1·K−1, -23.02 kJ·mol−1 and 58.68 kJ·mol−1, respectively. The electrochemical behavior of the chalcopyrite surface showed that a dense adsorption layer was formed on the chalcopyrite surface after MIXODT treatment.

Interaction mechanism of ferrate(VI) with arsenopyrite surface and its effect on flotation separation of chalcopyrite from arsenopyrite

Potassium ferrate (K2FeO4) was used as a novel environmental-friendly depressant, and its inhibition effect on flotation performance of arsenopyrite and chalcopyrite using potassium ethyl xanthate (PEX) as a collector was investigated by flotation experiments, contact angle measurements, adsorption measurements, localized electrochemical impedance spectroscopy (LEIS) measurements, and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that K2FeO4 strongly depressed arsenopyrite in a pH range of 4—11, and the flotation separation of chalcopyrite from arsenopyrite could be realized in the presence of 5×10—4 mol/L K2FeO4 and 5×10—5 mol/L PEX at pH 8 or 10. In the presence of K2FeO4 and PEX, the contact angle and the xanthate adsorption capacity of arsenopyrite decreased significantly. LEIS measurements showed that the addition of ferrate could significantly increase the impedance of the arsenopyrite surface. XPS analyses further confirmed that ferrate accelerated the oxidation of arsenopyrite surface.

Effect and mechanism of the xanthate/H2O2 addition order on flotation separation of chalcopyrite and sphalerite

Oxidation will affect the flotation of sulfide ore, but both sulfide ore and xanthate are easily oxidized, the role of oxidation in the flotation separation of sulfide ore is still unclear. In this study, different single mineral flotation tests were designed to explore the role of hydrogen peroxide (H2O2) in the flotation separation of chalcopyrite and sphalerite, and artificial mixed minerals tests was conducted to verify the selective depression effect of H2O2. Ultraviolet–visible (UV–vis) spectrometer, inductively coupled plasma-mass spectrometry (ICP-MS) measurement, microcalorimetry measurement, contact angle measurement, and Fourier transform infrared (FTIR) spectrometer were used to discuss the depressive mechanism of H2O2 on sphalerite. Flotation tests with different dosing methods show that mineral self-oxidation is the main reason for its depression. Both the chalcopyrite and sphalerite can be oxidized by H2O2, and the PBX adsorbed on its surfaces can also be desorbed by H2O2. However, sphalerite is easier to oxidize than chalcopyrite, and the PBX adsorbed on the surface of sphalerite is also easier to be desorbed. Therefore, sphalerite is selectively depressed by H2O2 in the flotation of chalcopyrite in the order of “mineral + PBX + H2O2″.

Flotation separation of chalcopyrite and pyrite via Fenton oxidation modification in a low alkaline acid mine drainage (AMD) system

The selective flotation separation of pyrite and chalcopyrite, and the comprehensive utilization of AMD play a vital role in the cleaner production of copper sulfide ore. In this paper, flotation separation of chalcopyrite and pyrite via Fenton oxidation modification in a low alkaline acid mine drainage (AMD) system was investigated. The results of micro-flotation experiment displayed that the maximum recovery difference between chalcopyrite and pyrite was 74.6% at recommended test conditions. The artificial mixed-mineral flotation experiment further confirmed the desirable flotation separation of minerals. Zeta potential, FTIR spectra analysis, contact angle measurement and adsorption amount analysis results confirmed that the hydrophilic species caused by Fenton oxidation could seriously hinder the interaction between pyrite surfaces and EX collector. Whereas, the Fenton oxidation had feeble influence on the floatability of chalcopyrite. The XPS study indicated that Fenton oxidation significantly increased the contents of SO42- on pyrite surfaces, and the concentration of SO42- increased from 5.9% to 37.65%. Meanwhile, this modification promoted the deep transformation of Fe chemical states mainly from Fe(Ⅱ)-S to Fe(III)–OOH and Fe2(SO4)3. As a result, the contents of Fe(III)–OOH and Fe2(SO4)3 reached 50.04% and 29.19%, respectively. For chalcopyrite, a small amount of oxide/hydroxide species were formed during this processing, and the chalcopyrite can interact with EX collector effectively. Thus, flotation separation of chalcopyrite and pyrite via Fenton oxidation modification in a low alkaline AMD system mainly attributes to the significant differences in the number and species of hydrophilic species.

Selective flotation of chalcopyrite from galena using a novel collector benzoic diethylcarbamothioic thioanhydride: An experimental and theoretical investigation

The flotation separation of chalcopyrite and galena has always been the focus of production. Benzoic diethylcarbamothioic thioanhydride (BDT) is a novel chelating collector that has shown a certain application strength in the field of sulfide ore flotation. In this research, micro-flotation tests, zeta potential tests, Fourier transform infrared spectroscopy measurements, X-ray photoelectron spectroscopy measurements, and density functional theory (DFT) calculations were used to investigate the selective recovery and selective adsorption of BDT on chalcopyrite and galena. The flotation results showed that BDT had good flotation selectivity for chalcopyrite and galena, which achieved up to 96.67 % and 50.26 %, respectively, at pH 6 using a collector dosage of 100 g/t. The analysis of the adsorption mechanism showed that CS and CO in BDT are mainly involved in the adsorption process. On the surface of chalcopyrite, CS and CO can form a six-membered chelating ring with Fe or Cu sites. BDT can also be adsorbed on the surface of galena in the same way, but the adsorption strength is weaker than that on the surface of chalcopyrite.

Effect of sodium silicate on the flotation separation of chalcopyrite and galena using sodium sulfite and sulfonated lignin as depressant

• Exploring the inhibitory effect of combination depressant for galena . • Exploring the enhancement effect of Na 2 SiO 3 on combination depressant. • Revealing the inhibition mechanism of combination depressant. • Revealing the enhancing mechanism of Na 2 SiO 3 to combination depressant. A combination depressant SHI was composed of sodium sulfite (Na 2 SO 3 ) and sulfonated lignin (SL) in a 5:1 M ratio. In this study, SHI and sodium silicate (Na 2 SiO 3 ) were employed to inhibit the floatability of galena, and the synergies between agents was explored. Micro-flotation results shown that after 2.4 × 10 −4 mol/L SHI was added, the recovery of galena and fine-galena declined by 53% and 36%, respectively. SHI exhibited excellent depressing efficiency toward galena. In the presence of Na 2 SiO 3 , the inhibitory effect of SHI was more obvious. Zeta potential measurements indicates that SHI and Na 2 SiO 3 altered the potential of galena surface through chemical reaction or adsorption action. The X-ray photoelectron spectroscopy results demonstrate that Na 2 SO 3 in the SHI were reacted with Pb ions on the galena surface and formed PbSO 3 , the SL was adsorbed by the galena surface through hydrogen bonding. In parallel, Na 2 SiO 3 interacted with the mineral surface by generating PbSiO 3. The addition of inhibitors increased the oxidation rate of the galena surface, thereby reducing the adsorption of collectors. Density functional theory simulations shown that Na 2 SiO 3 reduced the bonding energy between the galena surfaces and Na 2 SO 3 , and improved the stability of adsorption.

Effect of pre-oxidation on galena in the flotation separation of chalcopyrite from galena with calcium lignosulfonate as depressant

In this work, to achieve efficient separation of chalcopyrite from galena in Cu–Pb sulfide minerals, pre-oxidation by sodium persulfate (Na2S2O8) was used to magnify the differences in the floatability of two minerals in the presence of calcium lignosulfonate (CLS). The micro-flotation results of chalcopyrite and galena showed that pre-oxidation by Na2S2O8 could strengthen the depression performance of CLS on galena. The strengthening mechanism of Na2S2O8 to CLS adsorption onto the galena surface was revealed by local electrochemical impedance spectroscopy (LEIS), zeta-potential analysis, and X-ray photoelectron spectroscopy (XPS). LEIS showed that oxidation by Na2S2O8 contributed to the adsorption of CLS on the galena surface. XPS analysis demonstrated that the main oxidation species on the galena surface were PbSO4 and Pb(OH)+ in the presence of Na2S2O8 and that CLS interacted with oxidized galena by chemisorption. Zeta potential analysis indicated that a positive oxidation species was adsorbed on the galena surface; moreover, the oxidation species Pb(OH)+ endowed CLS on the galena surface with excellent adsorption performance. These findings are also supported by the results of the solution chemistry calculation. Galena also exhibits terrible surface reactivity and responds poorly to xanthate collectors after interaction with Na2S2O8 and CLS.

Selective separation of chalcopyrite from pyrite using an acetylacetone-based lime-free process

• Acetylacetone (AA) can selectively collect chalcopyrite from pyrite without lime at pH 9.0. • Fe atoms on chalcopyrite surface interact with AA to form a six-membered ring complex. • The reactivity of Fe atoms on chalcopyrite surface is higher than that on pyrite surface. • The adsorption energy of AA on chalcopyrite is greater than that on pyrite. In the flotation separation of chalcopyrite and pyrite, the commonly used high-lime process often causes problems such as losses of precious metals, blockage in pipelines and environmental pollution. In this study, acetylacetone (AA) was used as a novel collector to separate chalcopyrite from pyrite without adding limes. The flotation results indicate that AA can selectively separate chalcopyrite from pyrite without depressants at pH 9.0. Flotation kinetics and entrainment calculations show that compared with potassium ethyl xanthate (KEX), AA reduces pyrite entrainment and produces the concentrate with a higher Cu grade and a higher separation efficiency. Solution chemistry calculations show that enolate (AAE - ) and ketone (AAK) are the dominant species of AA at pH 9.0. Contact angle measurements, zeta potential measurements and Fourier transform infrared (FTIR) analysis indicate that the dominant species of AA chemically adsorb onto chalcopyrite surfaces at pH 9.0 while the adsorption on pyrite is minimal. Density functional theory (DFT) analysis reveals that the Fe atoms on chalcopyrite are the active sites interacting with AA to form six-membered ring complexes. The selective adsorption of AA relies on the spatial distribution and reactivity of Fe atoms on the commonly exposed cleavage surfaces of chalcopyrite and pyrite. After surface relaxation, a layer of Fe atoms appears on the outermost layer of chalcopyrite (1 1 2) surface, which is beneficial for the adsorption of AA species while a layer of S atoms for pyrite (1 0 0) surface. The Fe (III) on chalcopyrite (1 1 2) surface has a higher reactivity than the Fe (II) on pyrite (1 0 0) surface, leading to a higher adsorption energy of AA species on the chalcopyrite. Therefore, this acetylacetone-based lime-free process has a great potential for industrial application in the separation of chalcopyrite from pyrite.

Effect of peracetic acid as a depressant on the flotation separation of chalcopyrite from arsenopyrite

• Separation of arsenopyrite from chalcopyrite hindered by similar floatabilities. • Depression of arsenopyrite flotation required for better separation. • Effect of peracetic acid as a depressant of arsenopyrite was investigated in this study. • Found to greatly aid in flotation separation under neutral pH conditions. Arsenopyrite is an arsenic-bearing mineral that frequently occurs with chalcopyrite in polymetallic sulphide deposits. Their separation via existing methods and reagents involved in the flotation process, however, remains sub-par due to difficulties in the effective depression of arsenopyrite. In this study, the eco-friendly organic oxidant of peracetic acid (PAA, CH 3 C( O)OOH) was used for the first time ever to effectively depress arsenopyrite under conditions of neutral pH. Flotation experiments, adsorption tests, zeta potential analysis, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) were performed to investigate the depression mechanism of PAA on arsenopyrite. Single mineral flotation results showed PAA to have a massive depressive effect on arsenopyrite, reducing its froth recovery from 90% to 3% but only marginally affecting the froth recovery of chalcopyrite. Mixed minerals and bench-scale flotation tests further verified that PAA was an efficient arsenopyrite depressant. Adsorption test results, meanwhile, indicated that PAA could significantly reduce the adsorption of xanthate on the surface of arsenopyrite, but not on that of chalcopyrite. Zeta potential measurements, on the other hand, suggested a strong interaction between the surface of arsenopyrite and PAA compared with chalcopyrite, which induced a positive shift of zeta potential on the arsenopyrite surface. XPS analysis demonstrated that PAA only slightly oxidizes the surface of chalcopyrite, and a very small amount of iron oxide, sulfur oxide and copper oxide were generated, indicating that the surface was still hydrophobic. On the contrary, PAA could strongly oxidize the surface of arsenopyrite and generate a large number of oxygen-containing species, such as As(III)–O, As(V) − O, Fe(III) − O, Fe(III)–SO, SO 3 2− , and SO 4 2− . This was supported by measuring the contents of these oxides of iron, sulphur, and arsenic on the surface of arsenopyrite, which were found to increase from 47.13% to 88.56%, 14.95% to 45.49%, and 45.94% to 81.57%, respectively. Finally, hydrophilic oxide films containing AsO 2 − , AsO 3 − , SO 3 2− , Fe(OH) 3 , FeAsO 4 , and Fe 2 (SO 4 ) 3 were formed on the arsenopyrite surface, which further contributed to its depression.