Search Results (11)

The aim of this study is to explore the feasibility of using flotation wastewater from copper–porphyry ore processing to synthesize a gel that serves as a precursor for a polymer nanocomposite used in supercapacitor electrode fabrication. These wastewaters—characterized by high acidity and elevated concentrations of metal cations (Cu, Ni, Zn, Fe), sulfates, and organic reagents such as xanthates, oil (20 g/t ore), flotation frother (methyl isobutyl carbinol), and pyrite depressant (CaO, 500–1000 g/t), along with residues from molybdenum flotation (sulfuric acid, sodium hydrosulfide, and kerosene)—are byproducts of copper–porphyry gold-bearing ore beneficiation. The reduction of Ni powder in the wastewater induces the degradation and formation of a gel that captures both residual metal ions and organic compounds—particularly xanthates—which play a crucial role in the subsequent steps. The resulting gel is incorporated during the oxidative polymerization of aniline, forming a nanocomposite with a polyaniline matrix and embedded xanthate-based compounds. An asymmetric supercapacitor was assembled using the synthesized material as the cathodic electrode. Electrochemical tests revealed remarkable capacitance and cycling stability, demonstrating the potential of this novel approach both for the valorization of industrial waste streams and for enhancing the performance of energy storage devices. Full article

The use of mixtures of thiol collectors has been reported to benefit the flotation of Cu-Ni-PGM ores. However, the increasing reliance on recycled water in mineral processing may alter the performance of flotation reagents. This necessitates a deeper understanding of flotation reagents into their behaviour in different components or constituents of process water. This is crucial for better decision-making when determining the quality of process water that optimises reagent performance for specific ores. Ca²⁺ and Na⁺ are common cations in process water and are known to exert various effects in both the pulp and froth phases, making them frequent subjects of recent investigations into water quality. In contrast, NO₃⁻ anions have received less research attention compared to other common ions in process water, such as Cl⁻, SO₄²⁻, and S₂O₃²⁻, despite being present in significant concentrations. NO₃⁻ ions are understood to originate from blasting chemicals used during mining, leaching into solution during milling, and thus can be considered key players in the interactions occurring in the pulp phase. Their interactions in the pulp phase and their role in flotation are therefore important to consider. This work presents results from bench-scale batch flotation tests conducted on a Cu-Ni-PGM ore from the Merensky Reef, using mixtures of thiol collectors, namely sodium isobutyl xanthate and sodium diethyl dithiophosphate, in solutions containing Ca(NO₃)₂ and NaNO₃. NaNO₃ solutions showed higher solids recoveries for all thiol collector mixtures compared to Ca(NO₃)₂ solutions, this was attributed to increased gangue entrainment in Na⁺ compared to Ca²⁺. Higher Cu and Ni recoveries were observed in NaNO₃ solutions across all thiol collector mixtures; however, higher Cu and Ni grades were achieved in Ca(NO₃)₂ solutions compared to NaNO₃. Full article

BiOI microspheres were synthesized using the solvothermal method for the degradation of residual xanthate and gaseous nitric oxide (NO) under visible light irradiation. The as-prepared BiOI nanomaterials were then characterized using various technologies, including XRD, FE-SEM, TEM, UV-Vis DRS, and XPS. The photodegradation results show that the removal efficiency of isobutyl sodium xanthate can reach 98.08% at an initial xanthate concentration of 120 mg/L; that of NO is as high as 96.36% at an inlet NO concentration of 11 ppm. Moreover, the effects of operational parameters such as catalyst dosage, initial xanthate concentration, and pH value of wastewater on the removal of xanthate were investigated. The results of scavenging tests and full-spectrum scanning indicate that ·O₂⁻ radicals are the main active species in xanthate degradation, and peroxide xanthate is an intermediate. The reusability of BiOI was explored through cyclic experiments. Furthermore, the reaction path and the mechanism of NO removal using BiOI were analyzed, and the main active species was also ·O₂⁻. It is concluded that BiOI photocatalysts have high potential for wastewater treatment and waste gas clean-up in the mineral industry. Full article

Xanthates are by far the most widely used collectors in the froth flotation beneficiation of sulfide ores. However, the xanthate production process suffers from low yield, low productivity, long reaction time and environmental pollution. To address these issues, an effective method was developed for the synthesis of xanthates using phase transfer catalyst. Sodium isobutyl xanthate was synthesized from isobutyl alcohol ((CH₃)₂CHCH₂OH), sodium hydroxide (NaOH) and carbon disulfide (CS₂) with dichloromethane (CH₂Cl₂) as solvent and cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC), tetrabutylammonium bromide (TBAB) and tetrabutylammonium chloride (TBAC) as phase transfer catalyst. The compound was characterized by elemental analysis, infrared spectrum, ¹H NMR and ¹³C NMR. The influencing factors on the content and yield of sodium isobutyl xanthate including phase transfer catalyst type, phase transfer catalyst dosage and reaction time were studied by single-factor experiments. The influencing factors on the product purity and yield including reaction temperature, solvent volume, material ratio and rotating speed were studied by orthogonal experiments. The results showed that when the amount of TBAC was 3.0%m_alcohol, the reaction temperature was 35 °C, the solvent volume was 3.5 V_alcohol, the rotating speed was 180 rpm, the reaction time was 4 h and the material ratio was n[(CH₃)₂CHCH₂OH]:n(NaOH):n(CS₂) = 1:1:1.10, the product yield could be up to 86.66% and the product purity reached 82.56%. Full article

Inorganic electrolytes present in the process water used during froth flotation may have both beneficial and detrimental effects. These effects are said to be ion specific, as some ions may result in enhanced froth stability, increased mineral recoveries and decreased concentrate grades, while others may bring the opposite effects. Onsite process water quality variations have intensified the need to understand the relationship between inorganic electrolytes and flotation reagents on flotation performance. The use of mixtures of thiol collectors in sulfide flotation is a common practice across the globe; however, very few investigations have considered these in process waters of varying compositions. This study considers the effect of common cations, Na⁺ and Ca²⁺, in process water on the behavior of mixtures of thiol collectors. Single-salt solutions of NaCl and CaCl₂ at an ionic strength of 0.0213 mol·dm⁻³ were used to investigate the behavior of mixtures of two thiol collectors. These were carefully selected to understand how mixtures of thiol collectors behave in the presence of a monovalent cation versus a polyvalent cation. Bench-scale froth flotation tests were conducted using a Cu-Ni-PGM ore from the Merensky Reef. The results have shown that the divalent cation, Ca²⁺, resulted in higher %Cu and %Ni recoveries at all collector mixtures compared to the monovalent cation, Na⁺. The concentrate grades were, however, slightly compromised, as slightly more gangue reported to the concentrate in the presence of Ca²⁺. This behavior is attributed to the effect of polyvalent cations on bubble coalescence and froth stability. Full article

Tetrathionates have been found in significantly high concentrations in recycled process waters from massive sulphide ore processing plants. These polythionates react with xanthate added to flotation pulps thus reducing xanthate dosages in solution potentially affecting flotation performance. The current study focused on the effect of the tetrathionate-xanthate reaction on sulphide mineral recoveries. Ore dissolution studies confirmed the generation of tetrathionates by copper-lead-zinc ores. In 20 min, the tetrathionates consumed more than half of the xanthate in solution at pH 7. Rest potential measurements and Fourier transform infrared spectroscopy (FTIR) showed that the degree of collector-mineral interactions of xanthate and both galena and chalcopyrite was greatly reduced in the presence of a 2000 mg/L tetrathionate solution. Microflotation tests showed that chalcopyrite recovery was less sensitive to tetrathionates as indicated by small changes in mineral recoveries. Galena was sensitive to the action of tetrathionates on the mineral surface as the galena recovery significantly declined when floated with xanthate as a collector in both a 500 mg/L tetrathionate solution and a 2000 mg/L tetrathionate solution. These fundamental results lay a sound base on which more discussion into the significance and the effect of tetrathionates on flotation performance of sulphide ores can be developed. Full article

The effects of ZnSO₄ on arsenopyrite depression were studied with sodium carbonate and sodium isobutyl xanthate (SIBX) as the pH regulator and collector, respectively. In both micro and real ore flotation tests, ZnSO₄ showed better depression on arsenopyrite (pH 7.5–9.0 adjusted by Na₂CO₃) compared with sodium humate. The depression mechanism of ZnSO₄ on arsenopyrite flotation was studied by electrokinetic potential, adsorbed amount measurements, scanning electron microscope (SEM) observation and energy dispersive spectra (EDS) detection. The electrokinetic potential measurement results show a potential increase forpleas the arsenopyrite treated with ZnSO₄ in the pH range 7.5–9.0, which could be attributed to the formation of the precipitated zinc carbonate (ZnCO_3(S)). For arsenopyrite treated with both ZnSO₄ and SIBX, the electric surface potentials also display an increase, to approximate the values with solely ZnSO₄ treated, at pH 7.5–9.0, indicating the inhibition of ZnCO_3(S) upon the SIBX adsorption onto arsenopyrite. Adsorption results demonstrated that SIBX adsorption onto arsenopyrite indeed was inhibited at the pH 7.5-9.0 through the sharp decrease in SIBX adsorbed amount with ZnSO₄ as the depressant at this pH range. SEM observation and EDS detection results verify the formation of colloidal ZnCO₃ on the arsenopyrite, with ZnSO₄ as the depressant in combination with Na₂CO₃. Full article

The use of mixtures of thiol collectors is reportedly beneficial in sulfide flotation. This is becoming standard practice for many concentrators, but process water recirculation and re-use in flotation circuits may compromise the behaviour of such mixtures owing to changes in physicochemical interactions occurring in the pulp phase as a result of water quality variations. It is expected that changes in the pulp chemistry would in turn affect both the pulp and froth phase phenomena, thereby affecting flotation performance. Thus, this study considers mixtures of thiol collectors, sodium iso-butyl xanthate (SIBX), and sodium di-ethyl dithiophosphate (SEDTP) in degrading water quality. Bench-scale flotation tests were conducted on various molar ratios of the selected thiol collectors under different ionic strengths (0.0242 mol·dm⁻³ and 0.1212 mol·dm⁻³) of synthetic plant water. Increasing the ionic strength of synthetic plant water and SEDTP molar ratio resulted in an increase in water, solids, Cu, and Ni recoveries. Cu-Ni grades decreased in increasing SEDTP molar ratios. The highest Cu-Ni grades were obtained in degrading water quality. The increase in water and solids recoveries in increasing SEDTP and ionic strength of plant water is attributed to an increase in froth stability. It can be concluded that the increase in the ionic strength of plant water increased water recoveries and therefore froth stability in parallel with SEDTP’s froth stabilizing effect, thus suggesting an additive interaction on the froth stabilisation effect seen. Full article

The Norwegian mining industry is currently showing increasing interest in the production of metals. Recent research has demonstrated promising results identifying the high potential of the Nussir deposit for the production of copper and other valuable minerals. Mineralogical characterization for Nussir ore samples and their flotation concentrates was performed with optical microscopy and Zeiss automated mineralogy (Mineralogic) where the fine copper sulphide middlings were not completely recovered with a traditional sodium isobutyl xanthate (SIBX) collector. In the current study, dithiophosphate and a mixture of xanthate and dithiophosphate collectors’ interaction on copper and other gangue mineral components of the ore sample were investigated with zeta potential, quantitative adsorption, FTIR studies and Hallimond tube flotation. All the results for single mineral experiments confirmed the feasibility of selective copper sulphide flotation by disecondary butyl dithiophosphate (DBD) as collector. The blend of xanthate and dithiophosphate was chemically adsorbed as individual entities on the surface of the copper minerals via competitive adsorption. A systematic study with DBD and a mixed collector (SIBX and DBD) system was conducted on the coarse grind (−105 µm) of the Nussir ore sample, and the results showed a synergistic interaction between the two reagents. The beneficiated copper concentrate using this mixture of collectors is indeed of improved copper grade and recovery. The highest copper recovery in bench scale flotation was 95.3% with a concentrate grade of 19.4% Cu for DBD collector, whereas mixtures of dithiophosphate and xanthate collectors in the ratio of 3:1 resulted in the highest copper grade (24.7%) and recovery (96.3%). Full article

Norway has newly seen an upsurge of interest in exploiting its mineral deposits influenced by fresh Government focus and survey support for previously under-prospected areas. One of the major areas of interest is a huge copper deposit, operated by Nussir ASA, located in the Repparfjord tectonic window in the Caledonides of west Finnmark. The latest mineral resource estimation is from July 2014, which states that Nussir consists of 5.8 million tonnes of indicated resources and 60.2 million tonnes of inferred resources, giving 66 million tonnes of copper ore. This paper represents the first study on processing characteristics of this ore to date. Our parallel studies using xanthates and dithiophosphates as collectors for Nussir ore flotation examined the grade and recovery of copper, silver, gold, and platinum group (PGM) minerals. Therefore, in this subsequent study, a chelating agent n-Butoxycarbonyl-O-n-butyl thionocarbamate (BBT) is used as a collector and it was found that the recovery and grades of the economically interesting minerals are improved at as low as 2 × 10⁻⁵ M collector concentration. Zeta potential, Hallimond flotation and adsorption studies were initially performed in order to assess the selective interaction of BBT and its blend with SIBX (Sodium Isobutyl xanthate) on the three copper minerals of the ore. The bench scale flotation experiments were performed using mixtures of xanthate and thionocarbamate collectors of the Nussir ore and both the resulting copper recovery and grade employing these collector mixtures is observed to be 2–8% superior to the use of a single collector system. Additionally, the current study revealed that the metallurgical results are strongly influenced by the ratio of the collectors in the mixture and particularly the sequence of the collector addition. Full article

Recently, extraction of metals from different resources using a simple, efficient, and low-cost technique-known as bioleaching-has been widely considered, and has turned out to be an important global technology. Leptospirillum ferrooxidans and Acidithiobacillus (Thiobacillus) ferrooxidans are ubiquitous bacteria in the biomining industry. To date, the effects of commercial flotation reagents on the biooxidation activities of these bacteria have not been thoroughly studied. This investigation, by using various systematic measurement methods, studied the effects of various collectors and frothers (collectors: potassium amylxanthate, potassium isobutyl-xanthate, sodium ethylxanthate, potassium isopropylxanthate, and dithiophosphate; and frothers: pine oil and methyl isobutyl carbinol) on L. ferrooxidans and A. ferrooxidans activities. In general, results indicate that in the presence of these collectors and frothers, L. ferrooxidans is less sensitive than T. ferrooxidans. In addition, the inhibition effect of collectors on both bacteria is recommended in the following order: for the collectors, potassium isobutyl-xanthate > dithiophosphate > sodium ethylxanthate > potassium isobutyl-xanthate > potassium amylxanthate; and for the frothers, methyl isobutyl carbinol > pine oil. These results can be used for the optimization of biometallurgical processes or in the early stage of a process design for selection of flotation reagents. Full article