Extraction Of Precious Metals Research Articles

PRECIOUS METALS MARKET FORECASTING IN THE CURRENT ENVIRONMENT

The article analyzes trends in the precious metals market. The general characteristics and assessment of the most popular precious metals are given. The key factors influencing the supply and demand of precious metals are analyzed. Precious metals market forecasts have been developed. An analysis of the state of the world gold market in recent years has been carried out. Using the method of comparative analysis, modern trends in the supply and demand of this precious metal were revealed. The dynamics and structure of world gold reserves are considered. The world's precious metal reserves in different countries were also studied. The potential gold reserves in Ukraine are estimated. The production of precious metals in the world was studied. The rating of countries producing precious metals has been compiled. The leaders in this field have been identified based on the criteria of production capacities and growth rates of precious metals extraction. The structure of consumption of precious metals in the world is analyzed. The factors that lead to an increase in the rate of consumption of precious metals in modern conditions are considered. In particular, an increase in the current rate of commissioning of new solar energy capacities and an increase in the use of electric transport have been identified, which has significantly increased the demand for precious metals in the world. The impact on price dynamics of geopolitical and other economic factors, such as changes in trade relations between countries, currency fluctuations, market crises, changes in the monetary policy of central banks in many countries, and, above all, the increase in interest rates by the US Federal Reserve, was also studied. Considering these and other influencing factors, forecasts of the price dynamics of the precious metals market for 2024 and subsequent years were developed using a graphical method.

ჭაბურღილების ბურღვა ბოლნისის მუნიციპალიტეტის პოლიმეტალურ საბადოში არსებული ძვირფასი ლითონების მოსაპოვებლად

Wells for the extraction of precious metals at the poly deposit of Bolnisi municipality are drilled with EPIROC Christensen 140 Crawler Tier III and Atlas Copco Christensen CS 140 drilling rigs. In order to reduce the time required for lowering and removing the drill pipes and to remove the core qualitatively, without loss, and quickly, the Canadian detachable coring gun is used. Drilling wells is produced with CR-650 polymer powder (polyacrylamide) based drilling polymer solution, which, along with the removal of the drilled rock particles, lubricates and cools the drilling tools, and also prevents muds from hardening and, therefore, narrowing of the wellbore and jamming of the drill pipes. When drilling a well in fractured rock, a buffer solution is used to prevent absorption of the drilling fluid. The use of the above-mentioned modern methods has significantly improved the working time balance and technical-economic indicators of drilling.

Depletion of converter slags to waste in the Vanyukov furnace during pyrometallurgical copper production at JSC Almalyk MMC

The article shows the possibility of involving man-made formations in the pyrometallurgical production of copper in the form of slag and clinker-zinc production for the purpose of comprehensive extraction of non-ferrous and precious metals from them at Almalyk MMC JSC. Clinker, a technogenic waste from zinc production, contains a significant amount of reducing elements in the form of metallic iron and carbon, as well as gold in the amount of 2.3 g/t and silver 250 g/t. In research, clinker works as a reducer of magnetite contained in the converter slag during its depletion and in the process of depletion (reduction) of the converter slag, noble metals are extracted into matte, and then into blister copper up to 95-98%. Converter slags from copper production of Almalyk MMC JSC contain 2.0-3.5% copper, and they, as a circulating product, are depleted in a reverberatory furnace with copper extraction of 75%. To increase the yield of copper from converter slag in Vanyukov furnaces, it is necessary to first deplete the converter slag in reduction processes and then transfer it for processing. It was found that using clinker, a technogenic waste from zinc production with a particle size of +5 - -10 mm, the recovery of converter slag in a converter from magnetite to wustite using the developed technology in 10-15 minutes exceeded more than 50.0% (the amount of magnetite decreased from 21.9 % to 9.8%). As a result of processing recovered converter slags in the Vanyukov furnace, it was possible to reduce the copper content in converter slags of copper production from 2.2-3.5% to 0.58-0.72% in waste slag. To increase the yield of copper from converter slag in the reverberatory and Vanyukov furnaces, it is necessary to first deplete the converter slag in reduction processes and then transfer it for processing.

Highly selective recovery of gold and silver from E-waste via stepwise electrodeposition directly from the pregnant leaching solution enabled by the MoS2 cathode

The recycling of electronic waste, i.e., waste Printed Circuit Boards (WPCBs), provides substantial environmental and economic advantages. In fact, the concentration of valuable precious and base metals in WPCBs is even higher compared to those found in mined ores. Nevertheless, it is still challenging to selectively extract precious metals with low concentrations from the pregnant leaching solution, due to the co-deposition of base metals, like Cu, which have higher concentrations. In this research, stepwise recovery of precious metals and copper directly from WPCBs thiosulfate leaching solution was facilitated by the Ti cathode coated with MoS2 (MoS2/Ti). The in-situ enrichment of Au(S2O3)23- and Ag(S2O3)23- at the surface of MoS2 enables the high efficiency and selectivity of electrodeposition, which has been confirmed through COMSOL Multiphysics simulations and visualization. As a result, the first-step electrodeposition at 0.6 V recovered 92.44 % Au and 98.18 % Ag without any co-deposition of Cu. Subsequently, the second-step recovery employed a constant current of 0.03 A, achieving 100 % recovery of copper within 12 h. Furthermore, this study optimized the reduction potential, NH3·H2O concentration, and S2O32- concentration for the stepwise electrodeposition process. These findings provide valuable insights for establishing a closed loop circular economy in the electronics industry.

Intensifying separation of Pb and Sn from waste Pb-Sn alloy by ultrasound-assisted acid leaching: Selective dissolution and sonochemistry mechanism

Clean and efficient extraction and separation of precious metals from discarded Pb-Sn alloy is critical to the sustainable utilization of solid waste resources. Dense oxide layer and compact alloy texture in the waste Pb-Sn alloy pose challenges to the effective leaching process. Ultrasonic waves are demonstrated to improve separation efficiency via the favorable physical and chemical effects in solution system. In this study, ultrasound-assisted leaching technology is attempted to rapidly and selectively extract Pb from the waste Pb-Sn alloy, and gives emphasis on ultrasonic electrochemical behaviors. The Eh-pH diagrams of Sn-H2O and Pb-H2O systems were firstly analyzed to lay the selective dissolution foundation. It’s indicated that oxidizing HNO3 lixiviant is suitable to realize the selective separation of Pb. Both Sn and Pb can be dissolved to ionic Sn2+ and Pb2+ in the HNO3 solution. However, Sn2+ rapidly oxidizes to Sn4+ and Sn4+ further hydrolyzes to insoluble SnO2, which will agglomerate on unreacted materials to limit internal metal leaching in conventional leaching process. Due to the vibratory stripping of oxide layer by physical effect of ultrasound, the conventional acid leaching time for Pb extraction can be halved with the ultrasound assistance. About 99.12 % Pb and only 0.1 % Sn are dissolved in ultrasound-assisted leaching under the following optimal parameters: 0.5 mol/L HNO3, leaching temperature of 80 °C, time of 30 min, liquid-to-solid ratio of 20 mL/g, and ultrasound intensity of 0.52 W/cm2. Leaching kinetics of Pb, phase transition, microstructure evolution, Pb-Sn galvanic corrosion and dissolution polarization curve were studied to determine the ultrasonic enhanced dissolution mechanism. Notably, Pb and Sn form a microcorrosion galvanic cell in which Sn acts as a cathode and is protected while the Pb undergoes intensifying corrosion as the anode giving rise to the higher Pb dissolution efficiency. Eventually, it’s suggested that Pb can be rapidly extracted and separated from the waste Pb-Sn alloy during the ultrasound-assisted HNO3 leaching process via the ultrasound physical and chemical effects, especially the sonochemistry aspect of intensified spot corrosion and galvanic corrosion. The proposed ultrasonic electrochemical corrosion in this work were applicable to the extraction of valuable metals from various waste alloys through leaching method.

Selective separation of rare earth, Sr, Mo, and Zr from simulated raffinate of uranium/plutonium co-purification process

Spent fuel contains many elements including those that are radioactive. Separation and recovery of these substances have been challenging. This paper presents an efficient strategy for stepwise separation of the rare earth, strontium, molybdenum, and zirconium from the simulated raffinate of a uranium/plutonium co-purification process. This strategy employed three extractants with different metal ion selectivity, and cyclohexanediamine tetraacetic acid (CDTA) was introduced as a complexing agent to inhibit the extraction of Zr(IV) and precious metals. The recovery efficiency of all the rare earth elements was more than 97 % through the three-stage extraction, with N,N,N′,N′-tetranoctyl-diglycolamide (TODGA) as the extractant and N,N-dibutyloctanamide (DBOA) as the phase modifiers. Sr(II) was selectively recovered using N,N,N′,N′-tetracyclohexyl-diglycolamide (TCHDGA). A bisphosphonic acid extractant, N,N-hexadecylamine bis (methylene phenylphosphonic acid) (HADMPPA), was designed and synthesized for the selective separation of Zr(IV) and Mo(VI). The separation conditions of the recovered elements from other elements in each step were systematically examined. Moreover, the mechanism of the extraction reaction was investigated using FTIR spectroscopy, the slope method, and the equimolar series method. To our knowledge, this is the first time that four groups of major elements have been sequencially separated from the simulated high-level waste liquid in one process. This work could contribute to nuclear fuel reprocessing as well as the sustainable development of nuclear energy.

(Invited) Ratchet Based Ion Pumps for Selective Ion Separations

Even though highly selective ion pumps are found in the membrane of every living cell, artificial ion selective separation is a longstanding unmet challenge in science and engineering. The development of a membrane-based ion separation technology can drive a dramatic progress in a wide range of applications such as: water treatment, bio-medical devices, extraction of precious metals from sea water, chemical sensors, solar fuels and more. In this contribution we report the experimental demonstration of ion pumps based on a electronic ratchet mechanism.Electronic ratchets are devices that utilize a temporal modulation of a spatially asymmetric electric field to drive steady state current. Like peristaltic pumps, where the pump mechanism is not in direct contact with the pumped fluid, electronic ratchets induce a net current with no direct charge transport between the power source and the pumped charge carriers. Thus, electronic ratchets can be used to pump ions in steady state with no electrochemical reactions between the power source and the pumped ions resulting in an 'all-electric' ion pump.Ratchet-based ion pumps (RBIPs) were fabricated by coating the two surfaces of nano-porous alumina wafers with gold, thus forming nano-porous capacitor-like devices. The electric field within the nano-pores is modulated by oscillating the capacitor voltage. Thus, when immersed in a solution, ions within the pores experience a modulating electric field resulting in ratchet-based ion pumping. The RBIPs performance was studied for various input signals, geometries, and solutions. RBIPs were shown to drive ionic current densities of several uA/cm^2 even when opposed by an electrostatic force. A significant ratchet action was observed with input signal amplitudes as low as 0.1V thus demonstrating that RBIPs can drive an ionic current with no associated redox reactions.An important hallmark of ratchets is the ability to invert the direction of particle flow with a change in the input signal frequency. The stopping frequency, which is the frequency at which the particle flux changes its direction, is determined by the potential distribution and particles transport properties. As a result, for a given ratchet, there can be a frequency at which particles with the same charge, but different diffusion coefficients, are transported in opposite directions. This concept, that was never applied to ion separations, can enable the extraction of ions with extremely low relative concentrations if their diffusion coefficient is even slightly different from the main ions in the solution. We show by simulation, that for the prevalent ions in water, ions with a relative diffusion coefficient difference as small as 1% can be driven to opposite directions with a velocity difference as high as 1.2 mm/s. Since the direction of ion transport is determined by the input signal frequency, the sorting properties can be tuned in real time providing a simple fit-to-purpose solution for a variety of ion separations applications. Figure 1

Cloning and heterologous expression of Fusarium oxysporum nitrilase gene in Escherichia coli and evaluation in cyanide degradation

Cyanide is widely utilized in the extraction of precious metal extraction even though it has been deemed as the most toxic compound. Fusarium oxysporum has been shown to degrade cyanide through the activity of the Nitrilase enzyme. In this study, the coding sequence of nitrilase gene from F. oxysporum genomic DNA was optimized for cloning and expression in E. coli. The pUC57 containing synthetic optimized nitrilase gene was transferred into E. coli DH5α strain. This nitrilase gene was sub-cloned into pET26b (+) expression vector containing an in-built His-tag at the C-terminal end to facilitate its purification. The recombinant plasmid, pETAM1, was confirmed by PCR, digestion pattern, and sequencing. The recombinant protein was overproduced in E. coli BL21 (DE3). The results of the SDS-PAGE pattern and Western blot analysis confirmed the expression of the expected recombinant protein. For expression optimization of Nitrilase protein, M16 orthogonal experimental design of the Taguchi method was used. The effect of induction time, temperature and IPTG concentration were examined using four levels for each factors. Estimation of the amount of the expressed protein was calculated via densitometry on SDS-PAGE. The enzyme activity and expression in E. coli proved to be successful since there was ammonia production when potassium cyanide and acrylonitrile were used as substrates while the highest enzyme activity of 88% was expressed at 30 °C. The Km and Vm values of the expressed Nitrilase enzyme were determined to be 0.68 mM and 0.48 mM/min respectively.

Towards Sustainable H2O2 Photogeneration: Advancements, Challenges, and Future Prospects

AbstractHydrogen peroxide (H2O2) has emerged as a versatile and environmentally friendly oxidant, showing wide applications in diverse sectors such as fine chemical synthesis, waste stream treatment, precious metal extraction, and textile bleaching. With an escalating demand, H2O2 has now become one of the most essential chemicals worldwide. Efficient photocatalytic generation of H2O2 from water (H2O) and oxygen (O2) has been a long‐standing challenge, presenting a promising prospect to replace existing production methods. This review presents a framework aimed at achieving highly efficient and continuous H2O2 production via photocatalysis. The key aspects include photocatalyst design, selectivity for redox reactions, stability issue and reactor design. Through a comprehensive inspection and comparison of state‐of‐the‐art research, the most viable pathways for H2O2 photogeneration are identified, ensuring optimal solar‐to‐fuel conversion efficiency and high selectivity for target products. The ultimate goal is to establish H2O2 photogeneration as a sustainable and efficient method for producing this valuable chemical, contributing to a greener and more sustainable future.

Extraction of Au(III), Pt(IV), and Pd(II) from Aqueous Media with Deep Eutectic Solvent Dissolved in <i>n</i>-Heptane as Extractant

Due to the scarcity, studying precious metals extraction such as gold, platinum, and palladium is very critical. Solvent extraction is one of the established methods due to its simplicity and quickness but the low operational cost. In this study, a deep eutectic solvent (DES) consisting of decanoic acid and lidocaine in the molar ratio of 2:1 was applied as an extractant to extract Au(III), Pt(IV), and Pd(II) from aqueous media. Au(III) was solvated and extracted with DES in the form of AuCl3. Pd(II) was extracted by the cation exchange reaction between Pd2+ and H+. Complete extraction of Au(III) 98.2% and Pd(II) 100% can be achieved using 500 and 300 g/L DES, respectively. This finding opens new opportunities for improving Au(III) and Pd(II) extraction using an environmental friendly and inexpensive extractant.

Commercial organizations with foreign investments: problems of foreign economic activity in the field of precious metals mining

The article research the problematic issues of foreign economic activity and, in general, the financial and economic activities of commercial organizations with foreign investments operating in the field of precious metals mining. The author considers the dual nature of foreign direct investment as a factor that simultaneously contributes to the development of the national economy and creates risks and threats in the field of protecting and ensuring the security of the national economy from external interference. In the article, the author draws attention to the specific factors of foreign investment in the field of industrial production and mining, including the prevalence of the re-export nature of foreign investment and its causes, as well as the period of turnover of investments, which are also influenced by exchange rate differences. The article focuses on the consideration of specific sanctions that have been imposed on the sector of mining and production of precious metals, reveals their essence and specifics, and assesses their direct negative impact on mining and manufacturing enterprises in general, as well as their negative impact on commercial organizations with foreign investments, in particular. Sanctions are considered in the context of private and public sanctions measures, as well as from the position of countering them from the economic entities themselves. The article also examines the issues and provides a description of the practical aspects of direct anti-sanction and indirect public financial regulation, adversely affecting the financial and economic results of domestic enterprises operating in the field of production and extraction of precious metals

Towards Sustainable WEEE Management:Challenges, Insights and a Strategic Framework

Waste Electrical and Electronic Equipment (WEEE) management presents profound environmental challenges worldwide. In locales like Huila, Colombia, devising effective strategies is paramount for fostering sustainable trajectories. This investigation aims to identify the salient elements essential for developing a proficient approach to WEEE management in this region. Employing a predominantly qualitative mixed-methods approach, the study intertwines inductive, deductive, and abductive rationales, applying an interpretative perspective. Our sample encompassed 72 stakeholders active in WEEE management, extending from urban households to WEEE-focused businesses and environmental entities. Comprehensive questionnaires gathered data on socio-demographics, WEEE awareness, comprehension of relevant regulations, and associated practices. An exhaustive descriptive statistical analysis examined each variable's behavior, supplemented by visual representations and pivotal statistical parameters. These findings were further augmented by a SWOT analysis. Results emphasize the cardinal challenges in sculpting a strategic WEEE management pathway, yielding insights indispensable for policymakers intent on refining WEEE procedures. Moreover, the investigation introduces a methodical framework for secure, effective electronic waste handling, transportation, precious metal extraction, and disposal. Fundamentally, this research enriches the discourse on WEEE management, proffering pragmatic solutions with extensive ramifications. Received: 15 August 2023 / Accepted: 21 October 2023 / Published: 5 November 2023

Energy prices volatility, natural resource policy-making and green economic recovery in post COVID-19 era: Evidence from BRICS countries

The connectedness of natural resource volatility and economic growth has been an area of central attention for academicians and researchers before and even after the COVID-19 pandemic. The global as well as the Asian financial crises have negatively impacted the natural resources and economic growth of countries. Literature lacks the impact of crises on natural resources especially in BRICS economies. Hence, the current study examines the agriculture, livestock, crude oil, metal, and, coal-based natural resource commodities in determining the sustainable economic growth of BRICS countries. To achieve the objectives, data from the GSC index (Goldman Sachs Commodity Index) and different World Bank indicators is collected over a period from 2002 to 2022 which also includes the era of Post COVID-19 pandemic. Augmented dicky fuller test is used to explore the stationarity of constructs while ECM (error correction model) and Granger causality test are used to capture the connectedness between the explanatory and dependent variables. The empirical results infer that prices of commodities based on agriculture, livestock, oil, coal, and valuable metals are positively linked with sustainable economic performance in BRICS Countries. The results may be supportive of accelerating economic growth by improving the extraction and consumption of natural resources, livestock, agriculture, precious metals, oil, and coal.

Gold Leaching from Printed Circuit Boards Using a Novel Synergistic Effect of Glycine and Thiosulfate

Printed circuit boards (PCBs) are a secondary source for the extraction of precious metals, such as gold (Au), silver (Ag), platinum (Pt), palladium (Pd), etc. Thiosulfate and glycine systems have recently gained a significant amount of attention for Au leaching. However, in the thiosulfate system, the stability of leached Au tends to decrease when using lower thiosulfate concentrations. In this study, a copper–ammonia–thiosulfate system (thiosulfate system) and glycine or histidine were combined to leach Au from PCBs. The glycine–thiosulfate system resulted in a higher Au leaching than the histidine–thiosulfate system. The results revealed that the glycine–thiosulfate system exhibited a synergistic effect on Au leaching (93.7%) at pH 9.3 and 40 °C, while the Au leaching percentages were 47.1% and 50.7% for the thiosulfate and glycine systems, respectively. In the dual system, Fe leaching was insignificant, although Ag and Al leaching were 95.3% and 27.0%, respectively. Compared to the thiosulfate system, the dual system maintained the stability of the leached Au. The system required 60 mM thiosulfate and 0.5 M glycine at 40 °C and pH 9.3 in order to leach Au from PCBs. The kinetic study suggested that Au and Ag leaching from PCBs in the dual system followed the diffusion-controlled model. The Au leaching rate in the initial phase of the dual system was similar to that of the glycine–cyanide system. This novel, mild approach could be applied to hydrometallurgy to leach other precious metals from sources, such as ore and spent catalysts.

Efficient extraction and analysis of precious metals with a conducting polymer modified magnetic sorbent material

Polymerization of pyrrole-1-carbodithioic acid on silica coated Fe3O4 nanoparticles created the magnetic sorbent, PPy-CS2@SiO2@Fe3O4, for extraction and analysis of precious metals. PPy-CS2@SiO2@Fe3O4 is an air stable, granular composite readily dispersible in water and suitable for magnetic solid-phase extraction of Ru, Rh, Ir, Pd, Pt and Au. Maximum sorption and recovery was achieved at pH 6, 15 mg of sorbent and a 15 min extraction time, and a 4 mL desorption solution consisting of 2 M HNO3 and 0.5 M thiourea. Limits of detection (0.02 to 0.08 µg L−1), linear dynamic ranges (0.5 to 1000 µg L−1) and relative standard deviations (1.3 to 5.2%) were determined. Extraction with PPy-CS2@SiO2@Fe3O4 was not affected by a 400-fold excess of co-existing metals, allowing extraction from a complex chemical reaction mixture and produced water. Bulk sorption capacities for Pd2+ and Au3+ were 163.0 and 132.7 mg g−1, respectively, indicating larger scale extractions are possible.

Study on the extraction and separation of precious metals from wastewater using a hydrophobic deep eutectic solvent

Efficient and sustainable recovery of precious metals from the acidic leaching solution of solid waste is considered to be the main solution to the scarcity of precious metal resources. In this study, a hydrophobic deep eutectic solvent (HDES) was synthesized using trioctylmethylammonium chloride (N263) and oleic acid (OA). HDES was then used for the efficient recovery of Ir, Pt, Ru, and Rh from leaching solution containing precious metals. The effects of different molar ratios between N263 and OA, the initial pH of the aqueous phase, the oscillation time, and the phase ratio O/A of the extraction process were investigated. The organic phases were characterized analytically using ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, and electrospray ionization–mass spectrometry to further investigate the reaction mechanisms of the extraction process. The single-stage extraction percentages of Ir(IV), Ru(III), Pt(IV), and Rh(III) ions were 97.57%, 94.26%, 99.55%, and 15.1%, respectively. The high saturation extraction capacity of HDES enabled a high precious metal load, reaching 18.44 g L−1. Hydrogen bonds were formed between Cl-, which was bound by electrostatic force in the N263 structure, and H in the -COOH group in the OA molecule. During the extraction process, metal chloride complex ions replaced Cl- and entered the organic phase as 2[C17H33-COOH···N263+]IrCl62-, 3[C17H33-COOH···N263+]RuCl63-, 2[C17H33-COOH···N263+]PtCl62-, and 3[C17H33-COOH···N263+]RhCl63-. After scrubbing for effective removal of Cu and Fe in the loaded organic phase, different systems were used for stripping. The stripping percentage of precious metal ions reached more than 96.3%, providing efficient separation of the four precious metals from wastewater.

High-performance expanded graphite regenerated from spent lithium-ion batteries by integrated oxidation and purification method

Currently, the recycling of spent lithium-ion batteries (LIBs) has mainly been focused on the extraction of precious metals, such as lithium, cobalt and nickel from cathodes, while the waste graphite anode has been overlooked due to its low-cost production and abundant resources reserve. However, there are enormous potential value and pollution risk in the view of graphite recycling. Thus, we propose an original method to prepare expanded graphite (EG) as new anode material generated from waste graphite in LIBs which integrates the oxidation and purification in one-step. By regulating the oxidizability of potassium hypermanganate in the sulfur-phosphorus mixed acid system, the expansion of graphite and removal of impurities are realized simultaneously and thoroughly. As anticipated, the shortening of preparation process and purification procedure can also reduce the generation of polluting substances and production cost. It displays excellent electrochemical performance (reversible capacity of 435.8 mAh·g−1 at 0.1C and long-term cycling property of 370 mAh·g−1 at 1C after 1000 cycles), which is even higher than that of pristine commercial graphite. This delicate strategy of high-performance expanded graphite recycling achieves the integration of purification and value-added processes, providing the instructive guide to regenerate industrial-grade anode materials for the increasing LIBs demand in the future.

Systemic Economic Viability of Informal Sectors: E-Waste Management

The informal sector has been at India’s core of recycling WEEE for the last few decades. They do not have the scientific knowledge of processing e-waste and use acid baths and heat treatment to extract precious metals. The existing processes used by informal actors lead to a serious impact on their health as well as the environment. The introduction of advanced recycling technology for mitigating the hazardous effects on the environment and human health is as important as the development of technology for new-age electronic products. The social, economic, and environmental benefits to the informal sector can ensure formalized livelihoods in e-waste recycling by ensuring access to technology. The paper highlights how setting up a recycling facility and capacity building of the informal sector solves the problem of informality and its associated social, economic, and environmental evils, which will benefit the sector as a whole.

Extraction of metals with analyzed new reagents foaming agents SK-1, SK-2 from coals

The article presents the results of studies of brown and black coals from the Angren and Shargun deposits of the Republic of Uzbekistan. According to the results of the research, a number of different non-ferrous and noble metals were revealed in their composition: Tungsten up to 2 wt.% Au, Ag as well as rare earth elements (REE). Methods and techniques have been developed for the extraction of precious metals from coals: Ag, Au and rare earth elements Ge and Sc. Scientists of the laboratory of the Institute of General and Inorganic Chemistry “ChT, PG and Surfactants” synthesized new reagents - blowing agents SK-1, SK-2, which are used in the enrichment and flotation of non-ferrous and noble metal-containing coals. The method developed by us allows the integrated use of natural coal and can solve the important problem of ash and slag waste disposal and significantly reduce emissions of toxic elements into the atmosphere.

Mass balance and techno-economic study of a complete treatment chain of bio-oxidation for the extraction and recovery of precious metals from gold ore

A techno-economic feasibility study of a complete chain of bio-oxidation treatment for the extraction of gold ore with refractory character was carried out. Several basic parameters were considered, including operating and technical parameters, capitalization parameters, direct and indirect costs of the operation, and basic market parameters. The data generated were used to develop a preliminary techno-economic model. SuperPro Designer software was used to identify the industrialization potential of the project. With an estimated total capital investment (TCI) of 220 M$ and an estimated operating cost of 58.27 M$/a, we estimate that a total revenue of 78.48 M$/a is achievable. Other economic data were also estimated such as a gross margin of 25.75 %, a return on investment (ROI) of 15.82 %, a payback period of 6.32 years, and an internal rate of return (IRR) of 9.55 %. All this project was shown to have a net present value (NPV) of 34.40 M$ and an interest rate of 7 % per year, which is considered a profit. The process was shown to be most sensitive to the change in gold price.