查看更多>>摘要：? 2022 Elsevier LtdAn quaternary ammonium ionic liquid (1401) was synthesized through tetradecyl dimethyl benzyl ammonium chloride and sodium isobutyl xanthate. Firstly, it was used as a flotation collector for reverse flotation of silicates and sulfur from diaspore-type high-sulfur and high silicon bauxite. Results demonstrated that maximum Al2O3 recovery of 50.8% were achieved, the sulfur content and the ratio of A/S were 0.65% and 3.24. The results showed the 1401 has a stronger collecting ability and selectivity for diaspore compared with dodecyl trimethyl ammonium chloride and N-butyl xanthate. The adsorption mechanism of 1401 on the surface of diaspore, kaolinite and pyrite was studied by Fourier transform infrared spectroscopy (FTIR), zeta potential and X-ray photoelectron spectroscopy (XPS) analysis. Results indicated that physical adsorption was occurred between the 1401 and the surface of diaspore, kaolinite, and the adsorption amount on the surface of kaolinite is much greater than that of diaspore. And the chemisorption between the 1401 and pyrite was occurred and suggested that 1401 was preferred to adsorb on the surface of diaspore and pyrite. These results indicate that the quaternary ammonium ionic liquid 1401 can be used as the collector for reverse flotation of diaspore, providing new ideas for the utilization of bauxite.
查看更多>>摘要：? 2022 Elsevier LtdTo provide an understanding of the preferential interaction and flotation of Cu-activated arsenopyrite compared to pyrite, Cu species adsorbed, extent of surface oxidation, nature of bond and coordination between donor atoms of IPETC, and Cu and As acceptor atoms on mineral surfaces was investigated using X-ray photoelectrons spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analysis. Adsorption of Cu (II) and concurrent reduction to Cu(I) ions, which was paramount for the formation Cu-IPETC chelate complex was apparent on the surface of both pyrite and arsenopyrite from the XPS analysis. IPETC adsorption did not lead to removal of surface oxidation product on either pyrite or arsenopyrite surface, with extent of ferric hydroxide coverage on arsenopyrite far exceling that of pyrite. Adsorbed Cu(I) on the surface of pyrite was higher than arsenopyrite and was irreconcilable to their flotation performance. Bonding of S occurred with Cu(I), and As coordination with deprotonated N was suggested with the strength of the bond increasing at pH 11 using enargite as surrogate mineral. Roughing and single stage flotation of a refractory ore using 200 mg/l CuSO4 and 300 mg/l IPETC at pH 11 gave an Au and As grade of 26.2 g/t and 1.35% respectively, at a mass pull of 6.9 wt% and 82.2% Au recovery.
查看更多>>摘要：? 2022 The AuthorsUnderstanding and optimizing the comminution process in terms of mineral liberation, fragmentation, and fracture energy are aligned with sustainable approaches and overall international goals of green solutions. This study investigates the combined effect of material properties (ore textural features) and process factors (displacement rate) on mineral liberation, fracture energy, and fragmentation. For achieving this aim, multivariate data analysis tools are used to examine the fragmentation by compression of multiple layers of iron oxide minerals in a particle bed. The results indicate that ore textural features distinctively influence particle fragmentation, mineral liberation, and fracture energy and the ore textural effects are more pronounced compared to displacement rate.
查看更多>>摘要：? 2022The authors regret that the original paper was published with several inaccuracies in describing the bioproduction of biosurfactants used in the flotation studies, which do not affect the reported results. The authors would like to apologise for any inconvenience caused. The yeast strain name Candida bombicola should be replaced by Starmerella bombicola in all the occurrences describing the biosurfactants used in our study. Penicillium decumbensnaringinase should be read as Penicillium decumbens naringinase. β-nitro-phenylglucoside (β-NPG) was not used for the enzymatic synthesis of the glucolipid (GL), this compound was used as a reference in a series of separate enzyme assays. The reference to the paper by Van Renterghem et al. (2018) should be replaced by the paper by Saerens et al (2009): Saerens, K., Van Bogaert, I., Soetaert, W. and Vandamme, E. (2009), Production of glucolipids and specialty fatty acids from sophorolipids by Penicillium decumbens naringinase: Optimization and kinetics. Biotechnology Journal, 4, 517–524. https://doi.org/10.1002/biot.200800209. The reference to the paper by Van Renterghem et al. (2018) should be added after the following sentence: “Alcoholic glucoside (GS) is a by-product of the sophoroside production.”. The sentence “Alcoholic glucoside (GS)…can also be produced using Candida bombicola cultures with glucose as the main carbon source and 2-dodecanol as the co-substrate” should be followed by the reference to the paper by Brakemeier, A., Wullbrandt, D. and Lang, S. (1998) Candida bombicola: production of novel alkyl glycosides based on glucose/2-dodecanol. Appl. Microbiol. Biotechnol. 50, 161–166. https://link.springer.com/article/10.1007/s002530051271. The first sentence of Section 2.1 “ASL and GS were produced from S.bombicola, while GL was produced using Penicillium decumbensnaringinase at the Bio-base Europe pilot plant, Ghent, Belgium” should be read as follows: “Glucolipids were synthesized using Penicillium decumbens naringinase starting from the deacytelated acidic sophorolipids that were obtained from the fed-batch cultivation of Starmerella bombicola ATCC 22214 and subsequent alkaline hydrolysis.”. In the Supplementary part, the sentence “S. bombicola fatty alcohol oxidase knockout strains were obtained by integrating the S. bombicola gene under the regulatory control of its own promotor” should be as follows: “S. bombicola fatty alcohol oxidase (FAO1) knock-out strains were obtained by integrating the S. bombicola URA3 gene under the regulatory control of its own promoter at the FAO1 locus.” The correct reference at the end of this paragraph should be “(Van Renterghem et al., 2018)”.
查看更多>>摘要：? 2022A modified Couette rheometer is used to simulate mixing of polymer into clayey tailings, and to study the effects of shearing due to pipeline transport. It is found that a normalized torque correlates very strongly with performance indicators measured at the end of mixing and /or shearing, such as CST, oscillatory rheometry, and floc size distribution as inferred from optical microscopy, whether to evaluate a particular mixing strategy, or after simulated pipeline shear. With respect to polymer injection, the torque increases until reaching a peak value after which the torque sharply reduces. This point was found to correspond to the optimal dose, as characterized by the afore-mentioned performance indicators. For clayey tailings, it appears that this technique, as opposed to alternative torque-based techniques used in other industries such as wastewater floc conditioning, produces samples with superior performance indicators at the method-specific optimal dose.
查看更多>>摘要：? 2022 Elsevier LtdIn this paper, a clean separation technique of galena and chalcopyrite that innovatively combined a sulfuric acid pretreatment with collector-free flotation was proposed. X-ray diffraction (XRD) analysis, Scanning Electron Microscopy (SEM) determination, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) measurement, and flotation experiments were carried out to research on the surface differentiation of galena and chalcopyrite with sulfuric acid and the effect on their flotation performance. XRD analysis showed that significant characteristic peaks of a new species of lead sulfate (PbSO4) were formed in galena after sulfuric acid pretreatment, while chalcopyrite was not affected at all. SEM analysis and floatability results confirmed the effect of sulfuric acid on selective oxidation of galena surface. ToF-SIMS results further provided strong evidence for the conversion of sulfur ions to sulfate ions on galena surface. Lead sulfate species formed on the pretreated galena were detected at a thickness of 0–80 nm, which led to its loss of hydrophilicity and floatability. The experimental results of pretreatment-flotation separation of galena-chalcopyrite mixture and copper-lead sulfide mixed concentrate were in good agreement with the theoretical analysis. The results showed that the new method could effectively and thoroughly separate lead sulfide from copper sulfide ore, and the sulfuric acid in this technology could be recycled in the periodic pretreatment process. This work can enrich the surface inhibition theory of galena by sulfuric acid and provide an effective way for the separation of lead-copper sulfide ore.
查看更多>>摘要：? 2022 Elsevier LtdMolybdenite (MoS2), driven by its unique sandwich structure, is chemical inert and hydrophobic leading to a high refractory sulfide ore, and Co-white alloy, due to its grinding and corrosion resistance, is a refractory product (mainly containing Co, Fe, Cu and Si) for use in traditional hydro-metallurgical processing. In this work, a novel, two-step process was proposed to enhance the leaching performance of both molybdenite and Co-white alloy. First, prior to leaching and based on the sulfur affinity of Co, Fe and Cu, molybdenite and Co-white alloy were converted into ternary sulphides (MxMo6S8) with high leaching activity. Second, a leaching process was carried out in an autoclave with oxygen as the oxidant. Compared to molybdenite and Co-white alloy, the leaching performance of the ternary sulfides was greatly improved under moderate conditions. During the leaching of ternary sulfides, the sulfur is partially converted to elemental sulfur, which is unlike the acid leaching process of molybdenite where sulfur is oxidized to sulfuric acid. Factors affecting the decomposition of ternary sulfide were also studied in detail under moderate conditions. The optimal leaching conditions were found to be a temperature of 120 °C, a sulfuric acid concentration of 1 mol/L, a duration of 150 min, and an oxygen partial pressure of 0.95 MPa. The oxidation efficiency of molybdenum reached 99%, the elemental sulfur yield was 55%, and the leaching efficiencies of cobalt and copper were both greater than 99%.
查看更多>>摘要：? 2022 Elsevier LtdNitric acid pressure leaching (NAPL) of limonitic laterite is a recently developed technology by our group, which is in line with the concept of clean and sustainable development for the nickel industry. In this paper, an autoclave equipped with acid injection and sample withdrawal systems was used to investigate the behavior of nickel, iron, and mineral evolution during the leaching process. Afterward, a kinetic model was derived to describe the process of nickel dissolution. The results indicated that the temperature, acid concentration, and liquid–solid ratio were positively correlated with nickel extraction. Additionally, the dissolution process of goethite from a microscopic perspective was observed and confirmed, that the dissolution of goethite and the hydrolysis to produce hematite occurred simultaneously. Also, several kinetic models for characterizing the leaching of porous materials were tested. The grain model-pore diffusion control-cylindrical particle was chosen to describe nickel extraction. The kinetics equation can be summarized as [Formula presented], with an effective diffusivity of 4.59 × 10?10 m2/min at 210 °C. Consequently, it is concluded that the pores of goethite are the active sites and that the diffusion of the leaching agent within the pores is the controlling step of the reaction. This work serves the NAPL process for limonitic laterite and provides a foundation for more efficient extraction of nickel.
查看更多>>摘要：? 2022 Elsevier LtdThe inevitable presence of zinc ions will increase the difficulty of removing quartz from zinc oxide ores using sodium oleate (NaOl) as a collector. The problem of separating smithsonite from zinc ions activated quartz (Zn-Quartz) is still unresolved. In this study, a readily biodegradable and environmentally friendly reagent (tetrasodium iminodisuccinate, IDS) was introduced for efficiently separating them. Micro-flotation tests showed that IDS could selectively reduce the floatability of Zn-Quartz but barely influence that of smithsonite, and efficient separation of smithsonite from Zn-Quartz was realized. Zeta potential measurements demonstrated that the introduction of IDS prevented the adsorption of NaOl on the surface of Zn-Quartz, while had negligible interference on that of smithsonite surface. Furthermore, inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS) were used to further investigate the depressant mechanism of IDS on Zn-Quartz. The results illustrated that IDS could chemically react with zinc sites and desorb them from the surfaces of quartz, thereby depress the flotation of quartz.
查看更多>>摘要：? 2022 The Author(s)The stability of the froth is known to strongly affect flotation performance. Literature shows that both frothers and ions reduce bubble coalescence, and stabilise the bubbles that form, resulting in greater froth stability. Considering both variables act on the froth in a similar manner, it is becoming increasingly important to understand how frothers behave under conditions of increased ionic strength. Increasing the frother dosage stabilised the froth and increased the recovery of water and solids but had no impact on the recovery of copper and only a slightly positive influence on the recovery of nickel, with a simultaneous decrease in the grades of both copper and nickel. Increasing the ionic strength also stabilised the froth which increased the recovery of water and solids, but both the recoveries and grades of copper and nickel were unaffected. Examining both variables simultaneously revealed that ionic strength was more influential than frother dosage in the recovery of water with the opposite being true for the solids recoveries. This means that a simultaneous increase in ionic strength and decrease in frother dosage by the same amount will increase the water recoveries and decrease the solids recoveries. Such an increase will also slightly decrease the nickel recoveries while having no effect on the copper recoveries. Overall, managing the frother dosage under conditions of increased ionic strength, while still maintaining flotation performance, is possible. However, depending on the water quality, the frother dosage can be managed, this needs to be tailored to suit the requirements of the plant. Therefore, this study investigates the interrelationship between frother dosage and ionic strength within the context of flotation.
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