Inna G. AntropovaAryuna D. BudaevaDarya P. Khomoksonova
9页
查看更多>>摘要：This article is devoted to the study of deep processing of synnyrite, a potassium-rich aluminosilicate raw material of the Kalyumnoye deposit of the Synnyr alkalic rock massif (the Republic of Buryatia, Russia) to produce valuable agricultural (potassium magnesium sulfate) and technical (magnesium aluminate spinel) products. The study demonstrated the promise of this method of processing synnyrite, based on thermochemical activation of the original ore with magnesite instead of limestone, followed by sulfuric acid leaching. This approach signif-cantly reduces the cost of the thermochemical process and provides an additional useful product MgSO_4-6H_2O, which recuperates the initial magnesium additive and minimizes solid waste generation. This paper also presents a new method of processing alum KAl(SO_4)_2 obtained from synnyrite, based on sintering with potassium carbonate K_2CO_3 and brucite Mg(OH)_2 (or magnesium oxide) to produce potassium magnesium sulfate K_2Mg(SO_4)_2 and magnesium aluminate spinel MgAl_2O_4. The samples were characterized by DSC, chemical analysis, and XRD using the Rietveld method in TOPAS 4.2 software.
查看更多>>摘要：The secondary encapsulation of gold and silver by silicates and Fe-oxide during the roasting oxidation of refractory gold concentrate signifcantly infuence the gold and silver leaching effciency. In this study, a pre-treatment method of refractory gold concentrate calcine using ammonium bifuoride and sulfuric acid solution is proposed. The effects of the NH4HF2 and H2SO4 concentration, pretreatment temperature, and time on the leaching effciency of gold and silver were investigated in detail. The optimum conditions were determined to be NH4HF2 concentration of 1.5 mol/L, H2SO4 concentration of 2 mol/L, pretreatment temperature of 40?C, and duration of 90 min. The leaching effciency of gold and silver reached 97.6 % and 94.8 %, respectively. The pretreatment process of refractory gold concentrate calcine can be expressed with Johnson-Mehl-Avrami (JMA) equation and depends on the diffusion. The pretreated residue was mainly composed of silicates and Fe-oxide minerals. The gold and silver can be exposed to the ore surface by NH4HF2 pretreatment, which helps to improve its cyanide leaching effciency.
查看更多>>摘要：? 2022 Elsevier LtdIn this study, the impact of chloride content of the seawater on the solvent extraction equilibrium of copper using LIX 984 N was investigated. This effect was studied considering the nonideality of aqueous and organic phases. The presence of chloride ion was shown to increase the extraction tendency toward copper extraction, considering the changes that occur in the ratio of the activity of the dominant copper species to the hydrogen ion (H+). This phenomenon was further confirmed by calculating the equilibrium constant of the copper solvent extraction reaction in presence and absence of the chloride ion. The occurrence of the chloride ion resulted in involvement and dimerization of more organic molecules in the transfer of copper to the organic phase. As a result, a heterogeneous model incorporating the nonideality of the organic and aqueous phases for the solvent extraction of copper was developed and validated by experimental data.
查看更多>>摘要：? 2022 Elsevier LtdThis study investigates two phosphor samples with three processing routes to extract rare earth elements (REE). Acid leaching in 2 M HCl, 80 °C, 1 h yielded higher REE extraction in the compact fluorescent lamp (CFL) feed (82% Eu), with varying rare earth (RE) purity (77–97%) compared to fluorescent tubelight (TL) feed (69% Eu, 98–95% purity). Mechanical activation (MA) of 30 and 60 min caused partial dissociation of the LAP (LaPO4:Ce3+Tb3+) phase and yielded 34% Ce, 36% Tb, and 40% La. Transmission electron microscopy results revealed the formation of polycrystalline sites, which improved RE recovery. Alkali baking showed better REE extraction for both phosphors. 86.5% Y, 69% Eu was selectively extracted in feed acid leaching, and 100% La, 60% Tb, 20.6% Eu after alkali baking with 97% purity and CeO2 in the leach residue. The acid baking route was preferred for CFL phosphor with 91% REE (43 % Tb) extraction and 98% purity. TL phosphor was better for Tb extraction. The alkali baking of TL feed and acid baking of CFL feed yields 37.7% and ～30% rare earth oxides, respectively.
查看更多>>摘要：? 2022 Elsevier LtdThis research examined the the desulfurization of tailings from the Amaruq mine at a laboratory scale using froth flotation. Optimization of the flotation process was carried out by testing the conventional potassium amyl-xanthate collector (PAX) and three alternative collectors from the mercaptobenzothiazole (MBT) and dithiophosphate (DTP) families. The main goal was to assess the efficiency of the desulfurization process as a sustainable tailings management approach to prevent contaminated mine drainage generation. Mineralogical characterization of the Amaruq tailings using automated scanning microscopy (QEMSCAN?) revealed that the total sulfide and carbonate contents were about 8 wt% and 3 wt%, respectively; 63.39 % of the sulfur occurred as pyrrhotite, 30.17 % as pyrite, 3.63 % as gersdorffite, and 2.61 % as arsenopyrite. To compare the collector flotation yields, response surface methodology (RSM) was used for statistical design, analysis, and modelling of froth flotation experiments using three key-parameters: pH, activator (CuSO4) dosage, and collector dosage. Four quadratic mathematical models were developed for each collector to calculate sulfide recovery. Variance analysis (ANOVA) revealed that the factors that most affected sulfide recovery were collector type/dosage and pH. Process optimization yielded a maximum sulfide recovery of 96.73 % using 300 g/t PAX and 300 g/t CuSO4 at pH 11. A similar recovery of 95.83 % was achieved using an MBT-MTP based collector under the same conditions. The maximum recovery obtained using MTP and MTP-DTP based collectors while operating at optimal conditions (alkaline pH and maximum collector dosage at 350 g/t) was 88.65 %. The desulfurization process succeeded in decreasing the sulfur content in the tailings to<0.11 wt%. The final tailings were not acid-forming, as confirmed by the acid-base accounting (ABA) and net acid generation (NAG) static tests, compared to the highly acid-forming feed samples. Kinetic testing on the benign desulfurized tailings was also performed to predict and validate their acid generating potential, as well as their contaminant release rates (particularly As, Ni, Cu, Fe, and Zn). The Amaruq desulfurized material did not present any significant risk of contaminated mine drainage generation, and the leached contaminants did not exceed the criteria set by Quebec provincial legislation.
查看更多>>摘要：? 2022 Elsevier LtdA mineralogical study of Gon?alo lithium-bearing mica-rich pegmatite ore (Portugal) indicated that lepidolite occurs in coarse-grained textures, which allows an appreciable liberation of gangue minerals (quartz, k-feldspar, and albite) from lepidolite. However, the intergrowth of these gangue minerals results in uncomplicated liberation (i.e., inclusions). Taking advantage of this coarse gangue liberation, optical ore sorting through image analysis was attempted in order to predict the grades of different-sized fractions using a random comminution algorithm. The ore-sorting process allowed the production of a marketable Li pre-concentrate product for metallurgy. Moreover, this method also highlighted the possible valuation of the reject as low-Li-content quartz–feldspar mixtures for the ceramic industry (reduction in the temperature of porosity closing). Furthermore, a scaled approach of grinding and sieving allowed the formation of a lepidolite-rich fraction (>210 μm), which was processed using an electrostatic separator by varying key process parameters. The lepidolite and muscovite were separated to obtain a Li pre-concentrate assaying 3.5 % Li2O from a feed grade containing 1.8 % Li2O. Nevertheless, according to the zeta-potential measurements, the flotation test performed with the finer-sized fraction (–210 + 63 μm) showed that lepidolite flotation was optimised between pH 3 and 5. In this pH range, concentrates from the rougher stage assayed 4.2–4.5 % Li2O, corresponding to 87–95 % Li recovery. At pH > 5, the selectivity decreases, and SiO2 analysis suggests the flotation of quartz and other silicates rather than lepidolite. Feldspar/quartz flotation was also tested using lepidolite flotation rejects to promote the separation of feldspars from quartz and obtain products for ceramic applications.
查看更多>>摘要：? 2022The kinetics of arsenopyrite compact samples dissolution in nitric acid media was investigated using the full factorial experiment model (FFEM). The effects of nitric acid concentration (2–5 M), temperature (303–348 K), disk rotation frequency (3.33–10 rps) on the arsenopyrite dissolution rate were studied. Nitric acid concentration and temperature have a significant effect, and disk rotation frequency does not. With an increase in nitric acid concentration from 4 M to 5 M and temperature from 318 K to 333 K, the dissolution rates of iron and arsenic increase by 30.1–30.4 times, from 0.26–0.27 × 10–6 mol dm?2 s?1 to 7.83–8.21 × 10–6 mol dm?2 s?1. Increasing temperature to 348 K does not lead to a significant increase in the dissolution rate. The data obtained were processed using the FFEM to obtain kinetic equations (R2 = 0.95): WFe=0.04CHNO31.8e[Formula presented]ω0.1, WAs=0.04CHNO31.8e[Formula presented]ω0.1. Using SEM–EDS and XPS analyses, the mechanism of arsenopyrite passivation was determined. Under mild conditions (nitric acid concentration of 3 M and temperature of 303 K), local conglomerates containing iron polysulphides (Fe2Sx) are formed on the arsenopyrite surface. They do not create diffusion difficulties when dissolving arsenopyrite. Under harsh conditions (nitric acid concentration of 5 M and temperature of 333 K), polysulphides begin to aggregate. It leads to the formation of the passivating film containing elemental sulphur. The film is thin (20–30 μm) and porous. While the arsenopyrite dissolution rate is high. Further increase of parameters leads to thickening and compaction of the passivating film and decrease in the arsenopyrite dissolution rate.
查看更多>>摘要：? 2022 Elsevier LtdA disaccharide unit glycosaminoglycan named hyaluronic acid (HA) was exploited as a novel sphalerite depressant in the flotation separation of Pb-Zn sulfides in this study. The effect of HA on the flotation of galena and sphalerite were evaluated by micro-flotation tests. The depression mechanisms were investigated by adsorption capacity, Zeta potential and X-ray photoelectron spectroscopy (XPS) analysis. The results of micro-flotation tests proved that HA was an efficient and selective sphalerite depressant, which could depress sphalerite but hardly influence the flotation of galena to achieve desirable separation results using sodium isobutyl xanthate as collector. The results of adsorption capacity and Zeta potential tests suggested that HA was more inclined to adsorb on sphalerite surface than that of galena, which hindered the adsorption of SIBX on sphalerite surface but insignificantly affected the interaction of SIBX with galena surface. XPS results indicated that HA chemisorbed on sphalerite through the coordination of carboxyl and N-acetyl groups with Zn sites, whereas it physically adsorbed on galena surface by means of hydrophobic interaction.
查看更多>>摘要：? 2022 The AuthorsThe aim of the study was to develop a process option for the value addition of a leach residue from hydrometallurgical nickel refining. The residue in question is copper-rich (58 %) with sulphur (23 %), nickel (3 %) and iron (2 %) as the other main constituents. The prevailing phases are covellite and antlerite and the residue is already a marketable product as such. The current study suggests a flow sheet with moderate temperature autogenous pressure leach, selenium removal and copper electrowinning. Precious and platinum group metals will enrich the solid phase. Further solution purification is to be considered if London Metal Exchange grade copper is desired. The process was modelled in a steady-state and a proposal was made for integration into nickel refining. The bleed requirement from the developed copper circuit was 51 % of the spent electrolyte, which may be treated and utilised in the preceding nickel refining. In addition, sensitivity analysis was conducted to obtain data for adapting the copper circuit to suit nickel refining and navigate the way forward in the development project. The process simulation showed that the copper circuit, in the case of pressure leaching, would produce more than 300 kg of acid per tonne of feed, which would need to be bled out.
查看更多>>摘要：? 2022As an essential raw material for the tin industry, cassiterite ore needs to be effectively separated and purified, and the removal of impurities such as fluorite becomes the key to cassiterite flotation. In this study, the flotation separation of cassiterite (SnO2) and fluorite (CaF2) was enhanced by using hydroxylcitric acid (HCA) as fluorite inhibitor and 2-carboxyphenyl phosphonic acid (CEPPA) as collector. With a reagent scheme of 120 mg/L CEPPA and 4.5 mg/L HCA at pH 10.0, the flotation recovery of cassiterite and fluorite was 92.80% and 13.57%, respectively. Under the same experimental conditions of artificially mixed mineral flotation, the flotation index of cassiterite concentrate grade 78.19% and recovery 90.29% was obtained. The selective adsorption mechanism of CEPPA and HCA on minerals was investigated by Zeta potential, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results showed that CEPPA anions had chemically adsorbed on cassiterite and fluorite, and the adsorption of HCA on fluorite surface was stronger than that on cassiterite surface. XPS analyses further confirmed that Ca sites exposed on fluorite had a stronger affinity for HCA than cassiterite. Furthermore, the addition of HCA had little effect on the adsorption of CEPPA on cassiterite, while the strong chemisorption of HCA on fluorite surface prevented the adsorption of CEPPA on fluorite. These results provide a theoretical basis and promising new strategy for the flotation separation of cassiterite and fluorite.
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