Sodium Ethyl Xanthate Research Articles

Separation of copper-lead using 2,5-dimercapto-1,3,4-thiadiazole as chalcopyrite depressant: Adsorption and hydrophilicity studies

Galena separation from chalcopyrite poses a notable challenge in mineral processing, owing to the involvement of high dosages of traditional process reagents and substantial environmental impact. This study addresses this challenge by introducing 2,5-dimethoxy-1,3,4-thiadiazole (DMTD) as a chalcopyrite depressant using sodium ethyl xanthate (NaEX) as a collector. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses showed that DMTD can be adsorbed on the surfaces of chalcopyrite and galena, but the adsorption on chalcopyrite is stronger than that on galena. UV–vis, zeta potential and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses revealed that DMTD impeded the adsorption of NaEX on chalcopyrite; moreover, NaEX could desorb the DMTD adsorbed on galena and re-adsorb it on galena. Surface hydrophilicity tests revealed that DMTD significantly enhanced the hydrophilicity of chalcopyrite in the presence of NaEX, and galena was selectively separated from chalcopyrite using 1×10− 4 mol/L DMTD at pH exceeding 5. The recovery of galena remained >90 %, while that of chalcopyrite drastically decreased to <5 %. Furthermore, artificial-mixing experiments confirmed the separation effect of DMTD as a chalcopyrite depressant. Notably, this study avoids environmental pollution caused by traditional depressants, offering a potential green approach to achieve effective flotation separation of copper–lead sulfide ore.

Thiourea compounds with diverse hydrophobic group used as selective flotation collectors for galena

Hydrophobic group is a crucial yet underutilized component of a collector molecule. Herein we examine the flotation behaviors of thioureas with various hydrophobic groups for a galena/sphalerite mixed flotation system and compare them with sodium ethyl-xanthate (SEXT). Flotation experiments show that thiourea collectors with shorter alkyl chain and less nucleophilic amine nitrogen display better separation performance. Larger contact angles and adsorption capacities between the thiourea collectors and galena are the key to the enhanced selectivity.In the homogeneous Zn2+/Pb2+ mixed solution, thiourea collectors exhibit strong coordination ability with Pb2+, and their selectivities are noticeably higher than that of SEXT. FTIR and single crystal X-ray diffraction studies prove that thiourea collectors coordinate with metal ions through the S atom only. DFT calculations reveal how side-chain size and type can affect the selectivity.

Electrochemical activation of peroxydisulfate by Ti/IrTaO2 anode for quick degradation of xanthate

High concentrations of residual xanthate in mineral processing wastewater often limit the reuse of tailing water. Targeted removal of xanthate is an effective strategy for improving the tailing water recycling rate. In this study, the degradation efficiency and mechanism of sodium ethyl xanthate (SEX) in an electroactivated peroxydisulfate (EAPDS) system were investigated systematically. To avoid the influence of co-existing organic and inorganic matters in real flotation wastewater, we used simulated SEX wastewater to conduct the efficiency and mechanism investigation. A significant synergistic effect between electrocatalysis and peroxydisulfate was observed during the SEX decomposition. When the initial concentration of SEX was 200 mg/L, it achieved 100% removal rate only in 30 min with PDS dosage of 5 mM at current density of 10 mA/cm2. The introduction of peroxydisulfate boosted the removal efficiency six-fold compared to electrocatalysis alone. UV-Vis spectroscopy and GC-MS analyses revealed that the intermediate products of SEX were C2H5OH and CS2. The reactive oxygen species induced in the EAPDS were identified using a series of detection methods. •OH, 1O2, h+, O2•− and electron transportation process (ETP) all contributed to SEX removal. The degradation mechanism in the EAPDS system was proposed based on the analysis of the reactive oxygen species and products. Application to real flotation wastewater was attempted as well. The effects of different operating conditions were also evaluated, including pH, coexisting anions, PDS dosage, and current density. This study provides a new approach for the rapid removal of residual xanthates from mineral processing wastewater.

Visible-Light-Driven BiOBr-TiO2-Attapulgite Photocatalyst with Excellent Photocatalytic Activity for Multiple Xanthates

The novel ternary composites BiOBr-TiO2-attapulgite (BTA) were synthesized using a simple hydrothermal and water-bath method, exhibiting excellent photocatalytic performance to multiple xanthates. For the BTA photocatalyst, TiO2 and BiOBr were uniformly loaded onto the surface of acid-activated attapulgite. As a widely used collector in mining processes, sodium ethyl-xanthate (SEX) was selected as the target pollutant due to its high toxicity. The BTA ternary photocatalyst demonstrated significantly higher adsorption and photocatalytic degradation performance compared to TiO2 nanoparticles, BiOBr nanosheets, and BiOBr-TiO2 heterojunction. Structural characterization and experimental results indicated that the exceptional photocatalytic degradation efficiency of BTA was mainly attributed to the formation of a heterojunction between BiOBr and TiO2, as well as the presence of additional active adsorption sites provided by attapulgite. Free radical scavenging experiments and EPR results confirmed that the photogenerated holes were the predominant active species in photodegrading SEX throughout the entire experiment. The LC-MS results provided insight into potential degradation pathways of SEX. This research demonstrates that BTA, as a novel triple composite material, achieves rapid and complete degradation to 20 mg/L SEX within 20 min. This work presents a novel approach to synthesize mineral-based photocatalysts, which have broad prospects for application in flotation wastewater treatment.

Degradation of multiple xanthates using highly efficient visible light-responsive BiOBr-TiO2 composite photocatalysts

BiOBr-TiO2 (BT) composite photocatalysts were synthesized by using a two-step method including hydrothermal synthesis and water-bath precipitation. The microstructural characterization analysis proved that high-crystallinity and high-purity binary BT materials were achieved without by-products. TiO2 nanoparticles with a diameter of approximately 15 nm were decorated on multi-layered BiOBr nanosheets. The results showed that BT had highly-improved adsorption capacity and photocatalytic efficiency in comparison to pristine BiOBr and TiO2. The reaction rate constant of the optimal BT-2 composite photocatalysts for the degradation of 20 mg/L sodium ethyl-xanthate could reach 0.06496 min−1, which was 2.7 and 40.3 times than pure BiOBr and TiO2, respectively. The free radical scavenger test demonstrated that photogenerated holes were the main active species in the photocatalytic degradation reaction process. A possible degradation pathway for SEX molecules was provided through the interaction of visible light and BT-2 photocatalyst. The as-prepared BT materials can be used as efficient photocatalysts to completely degrade various types of xanthates under visible light.

The effect of copper ions on the surface chemistry of galena in near-neutral and alkaline solution

In the process of flotation separation of copper-lead sulfide ores, the adsorption of copper ions on the galena surface often occurs, which poses a significant challenge in the separation of copper and lead. The adsorption mechanism of copper ions on the galena surface and its impact on the adsorption of the collectors (i.e., sodium diethyldithiocarbamate (NaDDTC) and sodium ethyl xanthate (NaEX)) at different pH levels (6.5, 9.5, and 12.5) with a copper ions coverage of 0.14 pseudo-monolayers, were studied using zeta potential measurements, inductively coupled plasma-optical emission spectrometry (ICP-OES), ultraviolet–visible (UV–Vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The obtained results showed that copper ions were primarily bonded to the S sites on the galena surface, forming Cu(I) sulfides, which could subsequently react with NaDDTC and NaEX to form cuprous diethyldithiocarbamate and cuprous xanthate, respectively. It was observed that the presence of copper ions affects the adsorption capacity of the collectors on the galena surface, depending on the type of collectors and the solution pH. Furthermore, the reactivity of the collectors with Pb sites on the galena surface may be reduced in the presence of copper ions.

Modification and regulation of acid-activated kaolinite with TiO2 nanoparticles and their enhanced photocatalytic activity to sodium ethyl xanthate

ABSTRACT High photocatalytic activity composites of TiO2/acid-activated kaolinite (T/AK) were optimally constructed utilizing a simple hydrothermal method for the high-performance photocatalytic degradation to sodium ethyl xanthate (SEX) in mineral processing wastewater in this work. The synthesized T/AK composites under different preparation conditions were characterized by SEM, TEM, XRD, XPS, and UV-vis DRS to determine their structure, morphology, elemental composition, and photochemical properties. Compared with pristine TiO2 and kaolinite, the T/AK composites exhibited enhanced photocatalytic degradation performance to SEX due to their synergistic effects of adsorption and catalysis. The photocatalytic degradation efficiency of 0.4 g/L of 0.6T/AK composites to 30 mg/L of SEX reached 94% in 50 min under optimal preparation conditions, demonstrating that T/AK composites photocatalysts could effectively degrade toxic and corrosive SEX. The active radical studies revealed that the most significant active component in the photocatalytic system is h+ . The enhanced photocatalytic activity originated from its large specific surface area and suppressed the recombination rate of the photogenerated carriers of T/AK composites, which makes them great potential in wastewater treatment of mineral processing.

Effect of strong collectors and frothers on coarse particle flotation using the HydroFloat™ for a North American concentrator

ABSTRACT In conventional flotation, particles larger than 150 μm tend to float poorly, especially those with high specific gravity. The flotation equipment, HydroFloat™, has been implemented in the mining industry and has resulted in significant improvements in coarse particle recovery, particularly when used with strong collectors and frothers. A North American concentrator processing copper-molybdenum (Cu-Mo) ore has been having difficulties in recovering particles coarser than 150 μm. Presently, the concentrator uses sodium ethyl xanthate and X-133 frother (baseline). Previous tests conducted using stronger collectors and frothers showed that potassium amyl xanthate (PAX) and FrothPro 630 increased Cu recovery by 3% using a conventional laboratory flotation machine. In that testwork, chalcopyrite recovery for particles > 300 μm was low (~55%) under a range of testing conditions. Thus, the HydroFloat™ was tested using potassium ethyl xanthate and PAX in an attempt to increase Cu recovery for particles > 300 μm. Results showed that the recovery of chalcopyrite particles > 300 μm increased by more than 10%, depending on the test condition.

Selective flotation separation of galena from sphalerite via chelation collectors with different nitrogen functional groups

Nitrogen functional groups often provide excellent collecting selectivity and efficiency for collector molecules because of the rational alkalinity as Lewis base and the delicate affinity for metal ions. In this work, 1,3-diphenylthiourea (DPTU), 2-acetylhydrazine-1-carbothioamide (ADCT), (E)-1,5-diphenylthiocarbazone (DPTZ) were used as novel selective collectors for the flotation of galena/sphalerite mixed system, and universal collector sodium ethyl-xanthate (SEX) was used as the reference collector. The flotation results showed that collector with more nitrogen atoms (DPTZ) offered better selectivity for the flotation separation of galena from a galena/sphalerite mixed mineral system. Separation selectivity, FTIR and XPS studies showed, in the case that collector solution environment pH value < pKa value, N atoms did not participate in the coordination reaction. But in the opposite case, almost all N atoms in the collector molecule participated in the coordination reaction. As a result, there is stronger interaction between the collector molecule and the lead ion on the surface of galena, which was conducive to the selective flotation separation. The contact angle results showed that suitable hydrophobic groups were also critical to efficient separation.

Flotation Performance, Structure-Activity Relationship and Adsorption Mechanism of O-Isopropyl-N-Ethyl Thionocarbamate Collector for Elemental Sulfur in a High-Sulfur Residue

O-isopropyl-N-ethyl thionocarbamate (IPETC) collector was used to selectively recover elemental sulfur from a high-sulfur residue, and its flotation performance, structure–property relationship and adsorption mechanism to elemental sulfur were studied. The raw ore flotation test showed that IPETC displayed superior flotation performance to the elemental sulfur compared with sodium ethyl xanthate (SEX) and ammonium dibutyl dithiophosphate (ADDTP) collectors. Pure mineral flotation and adsorption experiments further demonstrated that among the three collectors, IPETC had the strongest collecting power and the optimum selectivity towards elemental sulfur. The structure–property relationship research based on density functional theory (DFT) calculation supported the above conclusion. The adsorption mechanism analysis manifested that IPETC adsorption on elemental sulfur surface was a chemical process by separately generating normal covalent bond between carbonyl S atom and S atom and a backdonation covalent bond between O atom and S atom, which was confirmed by the FTIR spectrum analysis result. IPETC exhibits excellent collecting ability and selectivity for elemental sulfur and therefore it has bright application prospects.

Chemical stability of xanthates, dithiophosphinates and hydroxamic acids in aqueous solutions and their environmental implications

Currently there is a wide variety of collectors used in mineral processing, the xanthates being the most used in sulfides flotation. Unfortunately, it is known that xanthates are not stable compounds and their decomposition generates carbon disulfide (CS2), a substance that is considered toxic. These aspects have motivated the search for collectors that exhibit superior performance without the health, safety and environmental (HSE) concerns associated with xanthates. In this study, the chemical stability of three xanthates of different alkyl groups (sodium ethyl xanthate (SEX), sodium isopropyl xanthate (SIPX) and potassium amyl xanthate (PAX)) was evaluated by UV/Vis spectroscopy, as a function of pH and time. Similarly, the chemical stability of three chelating collectors was evaluated: sodium di-isobutyl dithiophosphinate (SDIBDTPI), benzohydroxamic acid (BHA) and octanohydroxamic acid (OHA). Likewise, the surface tension of their aqueous solutions was measured making use of the Du Noüy method, to determine the critical micelle concentration (CMC). The results showed that the xanthate UV/Vis absorption spectra reflect the presence of a chemical reaction as the pH decreases from 4 to 2.5, which results in the formation of carbon disulfide (CS2). In addition, the generation of CS2 is favored as time elapses and the pH of the solutions decreases from 10 to 6, regardless of the hydrocarbon chain length. Conversely, dithiophosphinate and hydroxamic acids present greater chemical stability, although they form micelles at a certain concentration (CMC), a phenomenon that is not observed with xanthates. By not hydrolyzing, oxidizing, or decomposing into other chemical species, SDIBDTPI, BHA, and OHA may be considered environmentally friendly reagents. In the above context, it is important to promote the adoption of these collectors in mineral processing.

Recovering valuable metals from the leaching liquor of blended cathode material of spent lithium-ion battery

Blended cathode material for lithium-ion battery has been widely applied in electric vehicles, but effectively recovering valuable metals from the leaching liquor of blended cathode material is difficult due to the high content of manganese. In this study, an effective approach for recovering valuable metals from high-manganese leaching liquor of spent blended cathode materials is proposed. Firstly, 97.5% nickel and 100% cobalt in high-manganese leaching liquor are co-precipitated by sodium ethyl-xanthate under the optimum conditions of pH=5, 2 h, 50 °C and the dosage of sodium ethyl xanthate of 55 g·L-1. Then, over 95% nickel in precipitate is selectively leached into solution while almost 100% cobalt is still left in precipitate through a two-step ammonia leaching under the conditions of 2 mol·L-1 ammonia, 50 g·L-1 ammonium sulfate, L/S=8 ml·g-1, 1 h and 40 °C. Finally, the manganese and lithium left in leaching liquor are separated by solvent extraction. Over 99% manganese is effectively extracted and separated from lithium on the conditions of 40% vol D2EHPA, pH=5, 25 °C, the ratio of organic to aqueous (O:A)=1.25 and extraction time of 10 min. The whole recovering process is facile and can help effectively recycle lithium, nickel, cobalt and manganese from spent blended cathode materials.

Experimental and theoretical studies of sodium acetyldithiocarbamate for the removal of Cu2+ and Ni2+ from aqueous solution

With the continuous worsening of water pollution, the use of various collectors to remove heavy metal ions from aqueous solutions has attracted widespread attention. In this work, an acid-resistant collector, sodium acetyldithiocarbamate (ADTC) that combines acetamide with carbon disulfide was proposed for heavy metal removal. The structure of ADTC was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectrometer (NMR). Flame atomic absorption spectrophotometry (FAAS) was used to detect the concentration of metal ions in the solution before and after the treatment of the chelating agents. The chelation removal efficiency are compared for different chelating agents for Cu2+ and Ni2+ in acidic aqueous solution with pH = 1–7, and compared to the chelation removal efficiency of sodium diethyldithiocarbamate (DDTC) and sodium ethyl xanthate (SEX) chelating agents. The experimental results suggest the order of the chelating ability is ADTC > DDTC > SEX for Cu2+ and Ni2+. The chelating ability of ADTC to Ni2+ is stronger than that of Cu2+. The chelating ability of the collector is greatly affected by the pH value. The ADTC has a good chelating ability in the pH range of 3–7. The molecular orbital distribution, charge and electrostatic potential surfaces in quantum chemistry are used to explore the main active sites of the chelating agent are the S atom. The results of high resolution mass spectrometry showed that the ADTC is coordinated with the positive divalent metal ion in the ratio of 2:1. According to the results, the dithioamino (–NHCSS−) groups are coordinated with the positive divalent metal ion in a 2:1 ratio. Molecular dynamics simulation is used to explore the adsorption energy and binding strength of the chelating agent on the metal surface.

Investigating the Electrochemical Interaction of a Thiol Collector with Chalcopyrite and Galena in the Presence of a Mixed Microbial Community

High microbial cell counts have been recorded in sewage waters employed as process water in mineral beneficiation plants across the world. The presence of these microbes can negatively impact flotation performance through mineral passivation, although some microbes improve flotation performance as investigated in various bio-flotation studies. The current study aims to understand the electrochemical behaviour of minerals in the presence of a sodium ethyl xanthate (SEX) collector and microbes originating from a sulphide ore processing plant in South Africa. The electrochemical response was correlated to observe flotation performance. Mixed potential measurements were conducted in parallel to microflotation tests, to assess the hydrophilicity or hydrophobicity induced on sulphide minerals adapted to microbe-laden synthetic plant water. Sulphide minerals’ mixed potentials and interactions of SEX with sulphide minerals were dramatically reduced in the presence of the mixed microbial community (MMC). The observations were correlated with poor flotation efficacy noted in microflotation tests. These fundamental results shed light on how the adsorption of thiol collectors on sulphide minerals is adversely affected by microbes, prompting a discussion on flotation process monitoring when mineral beneficiation is conducted using microbe-laden water.

Comparative Effectiveness of Flotation Technique at Varying Conditions for Beneficiation of Itakpe and Agbaja Iron Ores

Itakpe and Agbaja iron ores are part of prominent iron deposits in Nigeria, yet studies on their beneficiation via froth flotation are relatively limited. Thus, this research investigated comparatively the flotation behaviour of both ores at varied pulp pH, particle size, and collector type. The ores were also examined using Energy Dispersive X-ray Fluorescence Spectroscopy, Petrological, and fractional sieve size analyses. Fifty (50) kg sample each of the ores was sourced for the research. Then, size fractions (63, 75, and 125 mm) of each ore were prepared and subjected to froth flotation using different collectors; Potassium Amyl Xanthate (PAX), Sodium Ethyl Xanthate (SEX), and Oleic Acid, at varying pulp pH ranging from 9-11. From the results obtained Itakpe iron ore assayed 36.18% Fe2O3 and contains predominantly haematite, sillimanite, and quartz while Agbaja iron ore contains chiefly, quartz and haematite, and assayed 40.6% Fe2O3 alongside 1.505% P2O5. The liberation sizes of both ores lie favouraby in the range -125+75 µm. Beneficiation studies carried out revealed that significant enrichment of both ores was actualized. Thus, it was established that Itakpe iron ore is best processed using PAX at pH 11 and particle size of 125 µm yielding concentrates assaying 67.66% Fe2O3 at a recovery of ~90% while for Agbaja iron ore, PAX at pH 9 and particle size of 63 µm is considered best to yield enriched concentrates assaying 65.5% Fe2O3 at 52.5%.recovery.

Comparative Effectiveness of Flotation Technique at Varying Conditions for Beneficiation of Itakpe and Agbaja Iron Ores

Itakpe and Agbaja iron ores are part of prominent iron deposits in Nigeria, yet studies on their beneficiation via froth flotation are relatively limited. Thus, this research investigated comparatively the flotation behaviour of both ores at varied pulp pH, particle size, and collector type. The ores were also examined using Energy Dispersive X-ray Fluorescence Spectroscopy, Petrological, and fractional sieve size analyses. Fifty (50) kg sample each of the ores was sourced for the research. Then, size fractions (63, 75, and 125 mm) of each ore were prepared and subjected to froth flotation using different collectors; Potassium Amyl Xanthate (PAX), Sodium Ethyl Xanthate (SEX), and Oleic Acid, at varying pulp pH ranging from 9-11. From the results obtained Itakpe iron ore assayed 36.18% Fe2O3 and contains predominantly haematite, sillimanite, and quartz while Agbaja iron ore contains chiefly, quartz and haematite, and assayed 40.6% Fe2O3 alongside 1.505% P2O5. The liberation sizes of both ores lie favouraby in the range -125+75 µm. Beneficiation studies carried out revealed that significant enrichment of both ores was actualized. Thus, it was established that Itakpe iron ore is best processed using PAX at pH 11 and particle size of 125 µm yielding concentrates assaying 67.66% Fe2O3 at a recovery of ~90% while for Agbaja iron ore, PAX at pH 9 and particle size of 63 µm is considered best to yield enriched concentrates assaying 65.5% Fe2O3 at 52.5%.recovery.

Study effects of conventional flotation reagents on bioleaching of zinc sulfide

Although flotation and bio-extraction of metals from its products are extensively investigated, there are few studied which evaluated the effects of reagents on bioleaching process. Both structure and concentration of flotation reagents are effective factors on microorganism activities. In this study, Kendall’s tau (τ) as a statistical method was used to statistically access the effect of typical sulfide flotation surfactants (collectors: potassium amyl-xanthate, potassium isobutyl-xanthate, sodium ethyl-xanthate, potassium isopropyl-xanthate, and Dithiophosphate), and frothers: pine oil and methyl isobutyl carbinol) on the bioleaching of Zn sulfides in a mixed culture (Leptospirillum ferrooxidans, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans). To consider both structure and concentration of these reagents, their molarities were used for the statistical evaluations. The Kendall assessments indicated that by increasing in the molarity of reagents, the pH value (the most effective factors of bioleaching) was increased (τ: 0.56) while the ORP value (τ: −0.54), Fe3+Fe2+ ratio (τ: −0.51) and numbers of oxidizing bacteria (τ: −0.38) in the solution were decreased. Therefore, as a result of these multi-interactions, by increasing the molarity of reagents, Zn recovery was decreased (τ: −0.45). These results potentially can be used for selection of flotation reagents when bioleaching would be the metallurgical metal extraction method.

Effects of Collectors and Frothers on Copper and Molybdenum Coarse Particle Recoveries—A Statistical Approach

Typically, coarse dense mineral particles greater than 150 μm are difficult to float, and the recovery decreases progressively. Various physical parameters can be manipulated in an attempt to increase the recovery. These physical parameters are the following: liberation, turbulence in the flotation cell, pH, collector, frother type and dosage. The testwork discussed in this paper was performed for a copper-molybdenum operation that is experiencing coarse particle (>150 μm) losses in the tails. This operation uses Diesel No. 2 fuel and sodium ethyl xanthate for molybdenum and copper flotation, respectively and X-133 frother. In an attempt to increase coarse particle recovery, stronger collectors (potassium amyl xanthate, Aero 249 and Aero 3501) and frothers (FrothPro 618, FrothPro 630 and FrothPro 706) were used. The analysis was performed using the Analysis of Variance (ANOVA) approach. The conditions required by the ANOVA method were met. The results showed that the collector potassium amyl xanthate (PAX) with frothers X-133 and FrothPro 630 resulted in approximately 3% increase in copper rougher recovery relative to the baseline (sodium ethyl xanthate and X-133). The collectors and frothers did not have a significant effect on molybdenum recovery within the dosage limits investigated.

Recovery of cobalt and zinc from the leaching solution of zinc smelting slag

Zinc smelting slag belongs to hazardous solid waste. Traditional pyrometallurgical or hydrometallurgical technology for treating zinc smelting slag focuses on zinc extraction but neglects cobalt recovery. With increasing cobalt demand and soaring cobalt price, recovering cobalt from zinc smelting slag not only helps alleviate resource shortage, but also improves the economic efficiency of zinc smelting slag recovery. In this study, a facile method for combination of recycling cobalt and zinc from the leaching solution of zinc smelting slag based on step-by-step removal of impurities and precipitation of cobalt processes was developed. First, impure iron ion was removed from acid leaching solution through the Fenton reaction by adding H2O2 and controlling the pH. The iron removal rate could reach 99%, and the content could be reduced to less than 1 mg/l. And then, copper and cadmium ions in the solution were extracted with zinc powder by cementation, and the removal rate reached 99%, reducing the content of copper and cadmium to 1 and 5 mg/l, respectively. Finally, cobalt was recovered by adding sodium ethyl xanthate. Almost 100% cobalt precipitation efficiency was obtained in this process under the optimum conditions of 8 g/l sodium ethyl xanthate, 1 g/l K2MnO4, pH 4, 55 °C, and 5 h. After precipitation, the cobalt ion concentration of the solution decreased to less than 1 mg/l, and a pure zinc solution with a concentration of 114.5 g/l was obtained. 88% cobalt and 98% zinc were recovered in the entire separation and purification processes.

Study of the effects of conventional reagents for sulfide flotation on bio-oxidation activity of Acidithiobacillus ferrooxidans

Bioleaching as a low cost and environment-friendly process could be a promising option for the enrichment of froth flotation products. Flotation reagents (collectors, frothers, etc.) are effective on the bacteria growth and oxidation activity; however, their impact has not been widely investigated. In this study, the effect of conventional reagents for sulfide flotation; collectors: potassium amylxanthate (KAX), potassium isobutyl-xanthate (KIBX), sodium ethylxanthate (NaEX), potassium isopropyl xanthate (KIPX) and Dithiophosphate (Aero3477), and frothers; pine oil (PO) and methyl isobutyl carbinol (MIBC) in various concentrations have been examined on Acidithiobacillus ferrooxidans activities. The results of this study demonstrate these flotation surfactants may have positive or negative influences on the bio-oxidation, based on their chemical compositions and/or concentrations. In general, the inhabitation effects of collectors would be increased in higher dosages and based on differences between results of various conditioning tests with the control test (without reagent) in different days, this effect could be considered by the following order: for 0.01 g/L: KAX > KIPX > KIBX > Aero3477 > NaEX, 0.1 g/L: NaEX > KIPX > KAX > KIBX > Aero3477, and 1 g/L: NaEX > KIPX > KIBX > KAX > Aero3477, and for frothers: MIBC > PO in all concentrates. These outputs potentially can be used for the selection of flotation surfactants when the flotation products are going to be further processed by bioleaching for the metallurgical extraction.