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Research analysis reveals factors influencing third-phase crud formation and composition during metal extraction, including solution composition, solid suspensions, organic compounds, colloidal compounds (e.g., silicic acid), and extractant purity. Compositional analysis of copper-containing sulfuric acid solutions (1.25 g/dm3 copper) identifies principal sulfate-forming components. Copper extraction was studied using extractants LIX 984N, ACORGA M5774, and M5640 at different ratios of the organic phase to the aqueous O:A (from 1:2 to 1:10). Suppressive impact of 10 vol.% CR60 additive on third-phase crud formation during copper extraction with LIX 984N, ACORGA M5774, and M5640 is analyzed, with ACORGA M5774 being the most effective. Physicochemical analysis characterizes CR60's active substance as poly(sodium 4-styrenesulfonate) with steel-suppression properties, and its structural formula is determined. Optimal copper extraction conditions establish ACORGA M5640's 24% efficiency, followed by ACORGA M5774 at 15%. CR60 reduces crud formation, with 5 cm3 of ACORGA CR60 added to sulfuric acid solution reducing interfacial crud formation by 2–3 times. Optimal extraction parameters include 1:2 O:A ratio, 20 ± 5 °C temperature, 5 cm3 CR60 additive, 5 min process duration, and 1-day settling time. ACORGA M5774 (10 vol.% in kerosene) is recommended as an extractant, with 2–3 stages of countercurrent extraction. [ABSTRACT FROM AUTHOR]

Purpose. The research aims to develop a technology for tailings solution purification using membrane nanofiltration to reduce waste volume and enterprise costs by reusing the purified water.       Methods. The research uses polyamide nanofiltration membranes on a semi-industrial plant. The nanofiltration process is conducted at a pressure of 3.5 MPa with 30% permeate yield. The chemical composition of the solutions is analyzed using atomic-absorption and chemical methods.       Findings. Removal of 69% arsenic, 68.5% zinc and 95.7% iron has been achieved under optimal conditions. The purified solution with a residual sulphuric acid concentration of ~3.5 g/l can be used again for leaching lead dust. The concentrated metal solution allows for additional zinc extraction. The use of technology reduces waste volumes by more than 30% and reduces the enterprise’s recycling costs.       Originality. The research proposes a new environmentally friendly nanofiltration technology for tailings solution purification that can effectively remove heavy metals and extract valuable components. This approach uniquely integrates membrane nanofiltration at an optimized pressure of 3.5 MPa, achieving high removal rates of heavy metal ions such as As3+, AsO43⁻, Zn2+, Fe2+, and Fe3+, while reducing waste by 30% and enabling the reuse of sulfuric acid and water in the leaching process, leading to significant cost and resource savings.       Practical implications. Implementation of the proposed technology at lead dust processing enterprises reduces the costs of wastewater treatment, reduces the waste volume and allows for the reuse of water and acids in the production process. [ABSTRACT FROM AUTHOR]

The g-C3N4 (GCN) adsorbent with two different morphologies, coral (CGCN) and nano fiber (GCNNF), was synthesized and recruited for extraction and preconcentration of lead and copper metal ions by effervescent salt-assisted dispersive micro solid phase extraction procedure. The structures of the two adsorbents were affirmed by Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and Brunauer–Emmett–Teller analyses. The factors affecting the extraction efficiency were carefully studied and the optimum values of the parameters for both adsorbents were pH 6.5, adsorbent dosage 8 mg, desorption time 3 min, and the elution solvent 300 μL of 2 mol L−1 of HNO3. The detection limits of Pb(II (and Cu(II) ions for CGCN were 0.9 and 0.3 μgL−1 and for GCNNF were 1.56 and 0.7 μgL−1, respectively. The percent relative standard deviations were obtained to be 1.32% and 2.23% for CGCN (n = 3) and 1.24% and 2.29% for GCNNF (n = 3), respectively for the lead and copper metal ions. In addition, the adsorbents could be used up to 7 times without an imperative reduction in the percentages of analytes recovery. Finally, the performance of CGCN and GCNNF were used for preconcentrate of lead and copper ions in honey, canned fish, and human hair samples. [ABSTRACT FROM AUTHOR]

We investigated the potential of tailings generated from chrysotile asbestos fiber production as a source of iron, nonferrous metals, and gold. We proposed the use of granulometric separation and systematically examined different enrichment processes, namely magnetic separation, gravity concentration, and enrichment using a Knelson concentrator, to extract the valuable components. The characterization of the initial tailing samples revealed that it comprises primarily of serpentine, brucite, antigorite, hematite, vustite, sillimanite, and magnesium oxide. Using the suggested enrichment process, we isolated gold, chromite, and nickel-cobalt concentrates as valuable products in addition to magnetite. The new approach exhibited high separation efficiency for iron, nonferrous metals, and gold, allowing their satisfactory extraction. [ABSTRACT FROM AUTHOR]

The extraction of lithium from a titanium wastes by selective acid leaching was explored. The preliminary leaching tests showed that diluted sulphuric acid could be used to leach lithium from the wastes. The recovery of lithium from a synthetic leach solution of the SMTC (spent melts of titanium chlorinators) using solvent extraction was studied. A number of extractants were investigated for the extraction of lithium and its separation from the other metals in the synthetic leach solution. It was found that amongst the three acidic organophosphorus extractants studied, D2EHPA performed best. With the organic system consisting of 0.05 M D2EHPA and 0.05 M TBP in Shellsol D70 under an A/O ratio of 5:1 at pH 0.25 and 40°C, over 97 % lithium was extracted and almost no iron and aluminium were co-extracted. The lithium extracted could be stripped from the D2EHPA/TBP system with 5 M NaOH to obtain LiOH product. [ABSTRACT FROM AUTHOR]

The article discusses about an effective system development for mining of thin deposits using small-sized self-propelled machines for high efficiency and completeness of mineral extraction. Furthermore, in this research are given the results of development of fine vein lodes by using sublevel system and high-performance, compact self-propelled machines. The developed technological scheme of ore extraction and delivery by self-propelled VSD is recommended to use in mining enterprises which develop vein deposits with varying thickness of ore and a wide range of occurrence angles. [ABSTRACT FROM AUTHOR]

This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact time at room temperature. These experiments addressed sorption kinetics and sorption isotherm. The maximum sorption capacity reached 55.8 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at initial uranium concentration of 0.62 mg·L−1. To describe sorption kinetics pseudo-first-order, pseudo-second-order and intraparticle diffusion models were proposed. Studies indicated that the sorption of uranium can be fitted by a pseudo-second-order kinetic model very well. Equilibria were described by Langmuir, Freundlich, and Dubinin–Radushkevich equations. The experimental sorption isotherm is successfully described by the Langmuir model. [ABSTRACT FROM AUTHOR]

Keeping the high potential of some microorganisms in adsorption of radionuclides in view, the adsorption properties of Enterobacter cloacae towards uranium were attentively scrutinized, and then it was used for preconcentration of uranium in different samples, using Enterobacter cloacae /carbon nanotube composite. First, using ultrasonic agitation, the effects of operational factors on biosorption of uranium on the inactive Enterobacter cloacae were appraised and modeled by central composite design, and a comprehensive study was performed on the equilibrium, kinetics, thermodynamic, and selectivity aspects of biosorption. The optimization studies along with the evaluations of the adsorption properties revealed that Enterobacter cloacae have a high affinity for fast and selective biosorption of uranium ions, at pH 5.1. Second, the Enterobacter cloacae /carbon nanotube was synthesized, characterized, and utilized for preconcentration of uranium in different samples, using a mini-column packed with the composite. The optimization of operational factors on recovery of uranium, using the central composite design, showed that uranium can be quantitively adsorbed at a sample flow rate lower than 4.5 mL min−1 and the desorption could be accomplished with 3.0 mL HCl 0.6 M solution. Finally, the mini-column was exploited for preconcentration and determination of uranium in different samples. The results revealed the low detection limit (0.015 μg.L−1), high precision (RSDs ≤3.92%), and good accuracy of the proposed procedure. Because of the adequate adsorption properties of Enterobacter cloacae towards uranium, it was utilized for preconcentration of uranium in different samples, using Enterobacter cloacae /carbon nanotube composite. [Display omitted] • Adsorption properties of Enterobacter cloacae for uranium were attentively scrutinized. • Effects of operational factors on the process were appraised by CCD. • Enterobacter cloacae /MWCNTs composite was utilized for preconcentration of uranium. • The results showed the efficiency of the proposed procedure for determination of U(VI). [ABSTRACT FROM AUTHOR]

Zr–Ca–Mg composite phosphates of various chemical compositions were prepared by facile heterogeneous synthesis and their adsorption properties towards 137Cs, 85,90Sr, 60Co radionuclides were studied. The obtained composites showed a high efficiency for 137Cs, 85,90Sr, and 60Co adsorption (K d > 104 mL/g) from model 0.1M NaNO 3 aqueous solution. A sharp decrease in adsorption properties was found against 0.01M CaCl 2 and seawater background, due to a decrease in the adsorbents selectivity. Zr–Ca–Mg phosphates exhibited high efficiency of radionuclides immobilization during metal ions leaching in water (desorption efficiency ∼10%). At the same time, the desorption rate of radionuclides in seawater solutions increased by 4–8 times. Calcination of saturated adsorbents at 1000 °C led significantly to increase in the efficiency of radionuclides immobilization. Thus, the activity of 60Со and 85Sr radionuclides in seawater solutions after exposure for 28 days did not exceed the lower detection limit, and the desorption efficiency of 137Cs was less than 4%. This was due to the formation of mixed Cо 0.5 Zr 0.5 (PO 4), SrZr 4 (PO 4) 6 phosphates, characterized by high efficiency of radionuclides immobilization. The obtained Zr–Ca–Mg composite phosphates are promising materials for the adsorption and immobilization of 137Cs, 85,90Sr, and 60Co radionuclides. • The adsorption of 137Cs, 85,90Sr, 60Co from model solutions was studied. • The high efficiency of Zr–Ca–Mg composite phosphates as adsorbents was shown. • The peculiarities of radionuclides leaching from saline solutions was established. • Enhanced radionuclides immobilization during adsorbents calcination was shown. • The mechanism of radionuclides adsorption and immobilization were carried out. [ABSTRACT FROM AUTHOR]