Valuable Components Research Articles

Modern Technologies Providing a Full Cycle of Geo-Resources Development

Resource-dependent countries and economies are found to be particularly sensitive to global shocks. A unifying parallel is drawn between resource-dependent countries and regions with depleted mineral resources. The objective factors of losses of accessed reserves are analyzed. A unifying parallel is drawn between sub-standard ores and industrial waste. The paper proposes shifting geotechnology development from simple mineral extraction towards technologies that provide a full cycle of geo-resources development. A radical way of ensuring a full cycle of geo-resources development is the involvement of sub-standard ores and industrial waste in a closed processing cycle. The utilization of industrial waste without a valuable component extracting or reducing a harmful component to a background value is palliative. A comparative description of various technologies that allow extracting valuable components from sub-standard ores and industrial waste is made. The paper proposes a variant of chemical–physical technology that makes it possible to extract a valuable component from industrial waste to a minimum value. The activation of industrial waste with a disintegrator before a chemical extraction significantly increases the yield of a valuable component from 2.6 to 218.5%. A differentiated approach is needed regarding the choice of leaching solution, its percentage, as well as the leaching method and the need for activation processing of valuable components and industrial ones. The combined highly efficient physical–chemical and physical–technical technologies will ensure the maximum extraction of the valuable component from 52.6 to 98.8% in the full cycle of natural and industrial geo-resources development.

Optimized extraction of mesoporous nanocomposites from spent Li-ion batteries and their use to construct high-performance supercapacitor devices with ultra-high stability

Lithium-ion batteries (LIBs) are one class of the most significant energy storage devices used nowadays. However, a huge number of spent batteries bring harmful resource waste and environmental hazards as LIBs are mainly composed of heavy metals and organic electrolytes. Consequently, recycling spent LIBs has become a hot topic lately, where researchers are actively working to develop a plethora of methods to extract valuable metals and components. In this study, mesoporous Li–Ni–Mn–Co oxide nanoparticles have been successfully extracted from spent Li-ion batteries using a simple microwave/precipitation method. The as-extracted Li–Ni–Mn–Co oxides were used to construct functional supercapacitor devices. However, the as-extracted oxides showed poor stability and low conductivity. To enhance their cycling stability and conductivity, fullerene (C76) is used as a carbon additive to form Li–Ni–Mn–Co oxide/C76 nanocomposite materials. The morphological, structural, and compositional analyses of those composites were performed using FESEM, HRTEM, XRD, and XPS techniques. The Li–Ni–Mn–Co oxide/C76 nanocomposites exhibit higher conductivity and wettability with an enhanced gravimetric capacitance of ∼357 Fg-1 at 1.0 Ag-1. The asymmetric supercapacitor devices deliver specific energy as high as ∼10 Wh/kg at a specific power of ∼800 W/kg with a superior retention rate of ∼115% after 20,000 cycles with ∼100% Coulombic efficiency.

Indigenous technical knowledge of Assam for pests management – Exploit potential in organic agriculture

One neighborhood investigation was conducted amongst 500 farmers of Nagaon, Golaghat, Jorhat and Dibrugarh districts of Central Brahmaputra valley Zone and Upper Brahmaputra valley Zone of Assam. Only 21.8% of farmers completely practiced the indigenous technology knowhow (ITK) for pest management, though 48.4% were aware about ITKs, whereas 41.8% famers apply synthetic chemical driven approaches. A total of 30 different types of ITKs had been collected which weresorted out crop wise and placed in different groups based on their use i.e. rice (20), pulses (1), tuber crops (3), vegetables (2) and fruits (4). It is speculated that a comprehensive study on different ITKs of Assam and their appropriate validation could be the valuable components for organic farming technology.

Upcycling end of lithium cobalt oxide batteries to electrocatalyst for oxygen reduction reaction in direct methanol fuel cell via sustainable approach

Recycling spent lithium-ion batteries (SLIBs) has become essential to preserve the environment and reclaim vital resources for sustainable development. The typical SLIBs recycling concentrated on separating valuable components had limitations, including high energy consumption and complicated separation processes. This work suggests a safe hydrometallurgical process to recover usable metallic cobalt from depleted LiCoO2 batteries by utilizing citric acid as leachant and hydrogen peroxide as an oxidizing agent, with ethanol as a selective precipitating agent. The anode graphite was also recovered and converted to graphene oxide (GO). The above components were directly resynthesized to cobalt-integrated nitrogen-doped graphene (Co@NG).The Co@NG showed a decent activity towards oxygen reduction reaction (ORR) with a half-wave potential of 0.880 V vs. RHE, almost similar to Pt/C (0.888 V vs. RHE) and with an onset potential of 0.92 V vs. RHE. The metal-nitrogen-carbon (Co-N-C) having the highest nitrogen content has decreased the barrier for ORR since the reaction was enhanced for Co@NG-800, as confirmed by density functional theory (DFT) simulations. The Co@NG cathode catalyst coupled with commercial Pt-Ru/C as anode catalyst exhibits excellent performance for direct methanol fuel cell (DMFC) with a peak power density of 34.7 mW cm−2 at a discharge current density of 120 mA cm−2 and decent stability, indicating the promising utilization of spent battery materials in DMFC applications. Besides, lithium was recovered from supernatant as lithium carbonate by coprecipitation process. This work avoids sophisticated elemental separation by utilizing SLIBs for other renewable energy applications, lowering the environmental concerns associated with recycling.

ТЕХНОЛОГИЯ КРИСТАЛЛИЗАЦИОННОГО РАЗДЕЛЕНИЯ НИКЕЛЯ И КАДМИЯ ПРИ ПЕРЕРАБОТКЕ НИКЕЛЬ-КАДМИЕВОЙ ЭЛЕКТРОДНОЙ МАССЫ ЩЕЛОЧНЫХ АККУМУЛЯТОРОВ

The main stages of processing nickel-cadmium electrode mass of alkaline batteries, including: sulfuric acid leaching and subsequent crystallization of the main components of the system - cadmium and nickel in the form of double sulfates MSO4·(NH4)2SO4·6H2O (Tutton's salts), where M = Ni, Cd. As a result of the research, regularities in the behavior of nickel and cadmium at the stage of leaching with a solution of sulfuric acid and crystallization of double sulfates were revealed. It is shown that the separation of cadmium and nickel in the sulfuric acid solution of leaching of nickel-cadmium battery mass by crystallization of nickel and cadmium-ammonium double sulfates is achieved in three stages with the formation of crystals of the composition NiSO4·(NH4)2SO4·6H2O, in two stages of crystallization and the degree of extraction of nickel 99 %, as well as CdSO4·(NH4)2SO4·6H2O and CdSO4·(NH4)2SO4 at the third stage of crystallization. Iron remains in solution after all valuable components have been isolated.

Ethanol and Methyl Jasmonate Fumigation Impact on Quality, Antioxidant Capacity, and Phytochemical Content of Broccoli Florets during Storage

Broccoli is a vegetable that offers valuable components, such as glucosinolates (GLS), flavonoids, and hydroxycinnamic acids (HCA), for our daily food intake. These substances have been associated with reducing the risk of cancer and cardiovascular diseases (CVD). Broccoli florets are also highly perishable, given their elevated respiration rates and their sensitivity to ethylene. Experiments have been carried out on broccoli to investigate the consequences of abiotic stress post-harvest treatments in retarding the senescence process. Nevertheless, the influence of these treatments on the phytochemicals of broccoli has not been extensively examined. Florets of broccoli (Brassica oleracea) were exposed to an atmosphere consisting of 10,000 µL.L−1 ethanol at room temperature for 30 min and 120 min. The exposure to methyl jasmonate (MeJA) treatments was carried out at room temperature using 1 µL.L−1 for 45 min and 180 min. The yellowing of florets was delayed using 10,000 µL.L−1 of ethanol at both exposure times as compared to untreated florets, and the chlorophyll titers were also superior with both doses over the control. The total phenols of the florets increased by 15% and 18% with the application of the hormetic and high doses, respectively, throughout the storage period compared to unexposed broccoli. The GLS and HCA yields were also increased by both ethanol doses. The exposure of florets to 1 µL.L1 MeJA for 45 min resulted in delayed yellowing of florets; however, longer exposures resulted in yellowing after 21 d and significantly (p < 0.05) increased respiration rates relative to untreated florets. Overall antioxidant capacity of the florets was significantly reduced with both doses of methyl jasmonate; however, HCA titers were increased at both doses. The amount of total glucobrassicins within broccoli was increased following exposure of florets to both doses, but no significant differences in glucoraphanin content were observed. As a conclusion, the ethanol treatment could indeed delay senescence and lead to the induction of phytochemicals. In contrast, MeJA’s effect on quality is not quite substantial; it can, however, be used to improve the phytochemical content of florets, particularly indole-type GLS.

Asteraceae Seeds as Alternative Ingredients in a Fibre-Rich Diet: Protein Quality and Metabolic Effects in Rats.

We verified whether milk thistle seeds and pot marigold seeds provided valuable components for a fibre-rich diet and how their addition affected body composition, nitrogen balance and lipid metabolism in rats. Growing rats were fed a control diet (5% fibre) or three fibre-rich diets (24% fibre), which contained cellulose as the sole source of fibre (24%; positive control), milk thistle seeds (32%) or pot marigold seeds (39%). All diets were balanced in macronutrients, including total protein content (9%), which was half of the amount recommended for rats to maximise protein absorption and utilisation, and the ratio of plant protein to animal protein (approx. 1:1). After 4 weeks, dietary pot marigold seeds reduced body weight gain, which translated into lower gains of body fat and lean mass in rats (all at p ≤ 0.05). Protein digestibility differed among individual fibre-rich diets (p ≤ 0.05), with the lowest result having been recorded for dietary pot marigold seeds (73%), followed by dietary milk thistle seeds (78%), and the highest result having been recorded for dietary soybean protein isolate (control protein source, 89%). Nitrogen retention was higher with dietary soybean protein isolate (53%) and dietary milk thistle seeds (47%) than with dietary pot marigold seeds (38%) (p ≤ 0.05). In the caecal digesta, the concentrations of the major short-chain fatty acids were almost or >2-fold higher after dietary milk thistle seeds and pot marigold seeds than after the positive control diet (all at p ≤ 0.05). Dietary pot marigold seeds enlarged the liver and increased the plasma activities of liver enzymes but reduced hepatic lipid contents (all at p ≤ 0.05). Certain Asteraceae seeds provide components of varied nutritional quality, with milk thistle seeds being a relatively good source of protein and both types of seeds being a source of fermentable fibre. Pot marigold seeds have potential anti-obesogenic effects, but with the risk of damaging internal organs.

Influence of natural conditions of southern Dagestan on formation of food substances in fruits of Golden Delises apples

The results of studying the amino acid composition, macroand microelements, vitamins and other food substances in Golden Delicious apples grown in terroirs located at various altitudes above sea level in the south of Dagestan are presented in order to determine cultivation sites with natural conditions contributing to the greatest accumulation of these valuable components in fruits. The elemental composition of apples was studied using flame and atomic absorption photometry, mass concentrations of amino acids by HPLC methods, the content of sugars, titrated acids, pectins and vitamin C – titrimetrically, phenols and vitamin P colorimetrically. It was found that natural factors of the fruit zone located on the plain cause a high concentration of sugars in Golden Delicious apples – 11,3 %, soluble dry substances – 14,9 % and minerals: potassium (135.5 mg%), calcium (19.0 mg%), sodium (25.6 mg%), magnesium (12.6 mg%) and iodine (2.4 μg%), and the climatic conditions of the foothills are favorable for the synthesis of titrated acids (0,51%), vitamins C (6,8 mg %) and P (63,1 mg %), phenolic (362,1 mg %) and pectin substances (0,83 %), as well as iron, zinc and copper. The difference in the formation of minerals in apples, depending on natural conditions and the altitude gradient of the place of growth, was: for potassium – 7,2; sodium – 8,2; calcium – 9,5; magnesium – 9,4; iron – 10,9; copper – 10,2; zinc – 9,3, iodine – 8,3 %. The total amount of amino acids in apples, depending on the culture site, ranged from 683,2 to 696,9 mg/dm3. In fruits from the foothills, the total mass concentrations of replaceable and essential amino acids were 1,3 and 5,9% higher, respectively, than in apples grown on the plain. The results of the study can be taken into account in the rational use of agroecological resources of fruit zones that differ in soil-climatic conditions and altitude gradient, as well as to reveal the biological potential of the Golden Delicious apple variety.

A clean two-stage Bayer process for achieving near-zero waste discharge from high-iron gibbsitic bauxite

The current Bayer process focused on alumina extraction without considering the comprehensive utilization of other valuable components, such as iron, and the resulting red mud caused severe ecological and environmental safety risks. This work proposed a clean two-stage Bayer digestion technology to obtain iron-rich red mud with low Na2O content from high-iron gibbsitic bauxite processing. The effects of digestion conditions on alumina extraction rate and iron enrichment degree in red mud were studied systematically. The ICP, XRD, SEM, and TEM were used to investigate the chemical compositions, phase structures and microstructures of bauxite and red mud. Results show that approximately 83% Al2O3 was extracted, and about 43% SiO2 was separated simultaneously in gibbsitic bauxite in the first stage, whereas undigested aluminum-bearing minerals mainly originated from substituted aluminum in goethite. Hydrogen was produced by the reaction of glycerol with sodium aluminate solution in the second stage, which promoting the reaction of Al-goethite with titanium-bearing minerals to form Fe(Ⅱ) and Ti(Ⅳ)-substituted hematite. The increase in reductants amount, caustic alkali concentration, reaction temperature, and time favored Al-goethite transformation in digestion. The total Al2O3 recovery and the Fe2O3 in red mud could reach more than 99% and 86%, respectively. Moreover, the content of Al2O3, SiO2, and Na2O in red mud satisfied the iron ore concentrate standard of GB/T 36704-2018, which was attributed to avoiding the generation of desilication products (DSP) in red mud. The 93% silicon could be removed from the liquid phase by two separations of the digested slurry. This work will facilitate the large-scale reduction of red mud discharge through further the value-added use of novel red mud technology in collaboration with steel and aluminum, achieving the green and sustainable development of the alumina industry.

Обґрунтування складу високобілкового концентрату для супів швидкого приготування

Proteins are the most valuable components in human nutrition due to the various functions they do in the organism. Meantime, the dramatic population growth on the Earth would threaten humanity with scarcity of proteinaceous food. Traditional agricultural technologies of breeding animals and microbiological processes would not provide obtaining the proper amounts and proper quality of proteins as the obligatory food component. Therefore, the search for new sources of food proteins as the economically profitable and convenient objects to be processed into half products and foodstuffs with use of innovative technologies is gaining topicality. By this day, industrial enterprises prefer soy and wheat proteins; however, the trend of studying the expedience of using the other grain and oil cultures, plant green mass, wild and cultivated mushrooms is rapidly proliferating. This article is dedicated to the studies of biochemical composition of cultivated mushrooms and the relevance to combine them with other high-protein materials (lentil flakes and linseed meal), in order to elaborate the concentrates for instant soups. Combining of two or three multi-component protein for tifiers in the compositional mixtures would give the unique possibility to regulate the functional properties of the latter and thenceforth to make their usage as convenient and to expand the range of foodstuffs with increased amount of proteins, essential primarily. The usage of such compositions can be epitomized by instant soups, the old and highly developed sector of food concentrate market that promotes obtaining various dishes wholly. The most famous trademarks are Knorr, Lipton, Batchelors, Heinz, Mivina, Vegeta, and also many domestic producers in Ukraine. Introduction of half products with balanced amino acid content and diverse functional purposes into food concentrate sphere is the topical challenge to updated food technologies, in particular foods for well-being

The Use of Silver Nitrate as an Elicitor to Increase Bioactive Compounds in Artichoke [Cynara cardunculus var. scolymus (L.) Fiori] Callus Culture

The globe artichoke belongs to the Asteraceae family and has become more and more popular among other vegetables due to its beneficial health-promoting features that are related to bioactive compounds present in leaves. The plant materials have inadequate proportions of valuable bioactive compounds in nature, so researchers are emphasizing on how to enhance their amounts. In vitro techniques with integrated novel practices can be employed to enhance phytochemicals from any plant. The current study aimed to determine and assess valuable bioactive components in 3 artichoke cultivars via callus cultures which were subjected to a treatment of 4 different concentrations (2.5, 5.0, 10.0, and 15.0 mg L-1) of silver nitrate. Results indicated that well-balanced levels of plant growth regulators were necessary for stimulating the callus formation of globe artichoke. The findings of the current study also revealed the importance of cultivar differences regarding callus formation. Experimental results revealed that variation in silver nitrate concentrations had a significant effect on biomass, total phenolic content and total antioxidant activities. The results of the current, study may offer a good strategy by promoting bioactive compounds of globe artichoke leaves for utilizing in large-scale industries, pharmacology, and food supplements.

FEATURES OF SORPTION OF CERIUM IONS BY THE INTERPOLYMER SYSTEM BASED ON AMBERLITE IR120 AND AB-17–8 ION-EXCHANGE RESINS

Many technological solutions contain valuable components as waste and can become an additional source of rare earth elements to meet the needs of modern production. The development of technologies based on commercially available and cheap sorbents opens up the possibility of extracting rare earth elements from various solutions. The aim of this work is to study the effect on the process of sorption of cerium ions from the corresponding sulfates by individual Amberlite IR120, AB-17-8 ion exchangers and an interpolymer system based on them. The experiments were carried out using the following physicochemical methods of analysis: conductometry, pH-metry, colorimetry, and atomic emission spectroscopy. Ion exchangers in the interpolymer system undergo remote interaction with a further transition to a highly ionized state. An optimal conformation is formed in the structure of the initial ion exchangers. A significant increase in the ionization of ion exchange resins occurs at a molar ratio of Amberlite IR120:AB-17-8 = 3:3. With this ratio, a significant increase in sorption properties is observed due to the mutual activation of ion exchangers. The average increase in the sorption properties of cerium ions in the Amberlite IR120:AB-17-8 = 3:3 interpolymer system is more than 85% compared to Amberlite IR120 and almost 70% compared to AB-17-8. A possible reason for the high sorption is the maximum correspondence between the globes of the interlayer chain of Amberlite IR120 and AB-17-8 bond ions after their mutual activation in an aqueous medium.

Ultrahigh-Frequency Hop Dryer with Tiered Resonators

Introduction. From the analysis of hop dryers of different systems and designs follows the prospect of hop drying by complex influence of the energy of the electromagnetic field of ultrahigh frequency and convective heat. Aim of the Article. The article aims at developing a small-sized microwave convective hop dryer with justified parameters for intensive drying technology of freshly harvested hops. Materials and Methods. Taking into account the justified criteria for the design of a hop dryer and the analysis of existing resonators, there was proposed a methodology for the development of a hop dryer with an energy supply in an electromagnetic field, including requirements for structural design, operational and economic indicators, and technology. The electrodynamic parameters of the resonator were investigated according to the CST Studio 2017 program. Results. The dielectric parameters of hops are theoretically investigated and functional dependences on humidity at a frequency of 2,450 MHz are obtained. The dynamics of hop heating is investigated when its dielectric loss factor changes during the action of an ultrahigh frequency electromagnetic field. There has been developed a design and technological scheme of a radio-hermetic microwave convective hop dryer of continuous flow action with tiered resonators for low-power agricultural enterprises. Resonators are arranged in tiers in the screening cylindrical housing: the first and third resonators are hemispherical, and the middle one is made in the form of an ellipsoid to ensure a high electric field strength. The transportation of raw materials takes place by rotating the discs in a gentle mode. Discussion and Conclusion. The expected specific energy costs of a hop dryer with a capacity of 12–13 kg/h at the microwave generator power of 4.0 kW for drying freshly harvested hops with a humidity of 76–82% to a humidity of 11–14% are 0.30–0.33 kWh/kg. The required electric field voltage of 2 kV/cm in all three resonators is provided, therefore, disinfection of raw materials occurs at a temperature of 65–70°C for 5–6 minutes of stay in three resonators. The intensity of moisture release from hop cones during endogenous convective heating increases 5–6 times compared to the convective drying method. The introduction of microwave drying technology using a convective method of evaporation and removal of moisture from the drying chamber reduces the duration of the process, saves valuable components of cones for brewing.

Emerging waste-to-wealth applications of fly ash for environmental remediation: A review

The considerable increase in world energy consumption owing to rising global population, intercontinental transportation and industrialization has posed numerous environmental concerns. Particularly, in order to meet the required electricity supply, thermal power plants for electricity generation are widely used in many countries. However, an annually excessive quantity of waste fly ash up to 1 billion tones was globally discarded from the combustion of various carbon-containing feedstocks in thermoelectricity plants. About half of the industrially generated fly ash is dumped into landfills and hence causing soil and water contamination. Nonetheless, fly ash still contains many valuable components and possesses outstanding physicochemical properties. Utilizing waste fly ash for producing value-added products has gained significant interests. Therefore, in this work, we reviewed the current implementation of fly ash-derived materials, namely, zeolite and geopolymer as efficient adsorbents for the environmental treatment of flue gas and polluted water. Additionally, the usage of fly ash as a catalyst support for the photodegradation of organic pollutants and reforming processes for the corresponding wastewater remediation and H2 energy generation is thoroughly covered. In comparison with conventional carbon-based adsorbents, fly ash-derived geopolymer and zeolite materials reportedly exhibited greater heavy metal ions removal and reached the maximum adsorption capacity of about 150 mg g−1. As a support for biogas reforming process, fly ash could enhance the activity of Ni catalyst with 96% and 97% of CO2 and CH4 conversions, respectively.

Emotion Dysregulation and Substance Use Risk and Protective Factors among Veterans in Residential Treatment

Background: Substance use disorders (SUDs) are frequent concerns among healthcare providers serving military personnel and Veterans, and SUDs are also associated with high healthcare utilization. Problematic substance use is consistently associated with deficits in emotion regulation, and changes in emotional regulatory processes may be important factors during treatment and recovery. Methods: The present study examined emotion regulation and substance use risk and protective factors among Veterans seeking residential treatment for SUD within the Veterans Health Administration (VHA). Data were collected from 138 Veterans at pre-treatment and post-treatment to examine if changes in emotion regulation were associated with post-treatment outcomes. Results: Results indicated difficulties with emotion dysregulation at discharge predicted substance use risk factors, but not substance use protective factors, after controlling for scores at intake. Emotion regulation significantly improved throughout the course of treatment. Facets of emotion dysregulation at post-treatment, specifically difficulties engaging in goal-directed behavior, lower emotional clarity, lower emotional awareness, and more impulse control difficulties, predicted future admission to withdrawal management services, but not future mental health engagement, mortality, or resumed use (positive urine drug screen). Conclusions: Emotion regulation skills may be valuable treatment components, as they are related to reduced substance use risk factors; however, the results of improved emotion regulation were mixed for other measures of treatment outcome.

Opuntia spp.: An Overview of the Bioactive Profile and Food Applications of This Versatile Crop Adapted to Arid Lands

Opuntia spp. are crops well adapted to adverse environments and have great economic potential. Their constituents, including fruits, cladodes, and flowers, have a high nutritional value and are rich in value-added compounds. Cladodes have an appreciable content in dietary fiber, as well as bioactive compounds such as kaempferol, quercetin, and isorhamnetin. Fruits are a major source of bioactive compounds such as phenolic acids and vitamin C. The seeds are mainly composed of unsaturated fatty acids and vitamin E. The flowers are also rich in phenolic compounds. Therefore, in addition to their traditional uses, the different plant fractions can be processed to meet multiple applications in the food industry. Several bakery products have been developed with the incorporation of cladode flour. Pectin and mucilage obtained from cladodes can act as edible films and coatings. Fruits, fruit extracts, and fruit by-products have been mixed into food products, increasing their antioxidant capacity and extending their shelf life. Betalains, obtained from fruits, can be used as food colorants and demonstrate promising applications as a sensor in food packaging. This work reviews the most valuable components of the different fractions of this plant and emphasizes its most recent food applications, demonstrating its outstanding value.

Структурные изменения железистых кварцитов под действием лазерного излучения

The development of modern technologies for the complex extraction of valuable components from refractory ores and technogenic deposits is possible on the basis of the latest achievements of fundamental sciences, a combination of physicochemical, enrichment and metallurgical processes. The article presents the results of a study of the structure of ferruginous quartzites during laser processing. Changes in the Raman scattering spectra under various energy impacts are revealed.

Copper recovery from waste printed circuit boards with small peptides enhanced by ultrasound

Waste printed circuit boards (WPCBs) are one of the most critical and valuable components in electronic equipment. WPCBs contain many metals (Cu accounts for more than 90%), which are a potential secondary resource to overcome metal scarcity. The recovery of metals from WPCBs is significant for environmental protection and resource reuse. This investigation presents a simple and sustainable approach to leach Cu from WPCBs with small peptides enhanced by ultrasound. Various leaching parameters, including initial small peptides concentration, temperature and initial H2O2 volume fraction have a highly significant influence. The maximum Cu leaching were 95.4 ± 0.1%, 92.5 ± 0.1% and 87.4 ± 0.1% by glutathione (GSH), glycylglycine (GG), and glycyl-L-glutamine (GLG), which caused by the differences of small peptides functional groups. The Cu leaching by ultrasound exhibited 2.1–3.9 folds higher than without ultrasound treatment. The kinetic analysis showed that the Cu leaching from WPCBs was mainly controlled by diffusion and chemical reactions. The coordination numbers of copper-chelating GSH (CC-GSH), copper-chelating GG (CC-GG), and copper-chelating GLG (CC-GLG) were measured by simulation experiments. The hydroxyl, carboxyl, amino and sulfhydryl groups are the main reasons for the complexation of small peptides and Cu2+, which was confirmed by the characterization of copper-chelating small peptides (CCPs) crystal. The Cu leaching with small peptides enhanced by ultrasound potentially represents an innovative technology with significant advantages in metals extraction and time efficiency. Furthermore, the results provide perspectives and new insights into the preparation of CCPs and the industrial application of modified leaching residues.

STUDY OF CONDITIONS FOR THE ASSOCIATED EXTRACTION OF VANADIUM AND GALLIUM DURING ALKALINE LEACHING OF RAW ALUNITE ORE

Alunite ore containing a significant amount of aluminum, iron oxide, titanium dioxide, and other valuable components (Ga – 0.003 wt%, V – 0.0315 wt.%) is the main raw material for the production of alumina and promising raw material for the production of gallium and vanadium. This paper studies the dynamics of the distribution of gallium and vanadium in the liquid phase during the dissolution of raw alunite in an alkaline solution are studied. The results have showed that alkali concentration, leaching temperature, liquid-to-solid ratio have a significant effect on the degree of extraction of these elements from solution. It has been found that when raw alunite ore is leached with a 5% NaOH solution (S:L=1:6) for 2 hours, the degree of extraction of Ga and V is, respectively, 50.2 and 59.23% of their total content in the rock

Green synthesis of aluminum hydroxide from alumina–silica based solid hazardous waste

The collaborative detoxification and extraction of valuable resources from various industrial wastes are proposed based on the composition characteristics and toxic properties of different solid/hazardous wastes such as coal gangue, aluminum dross, red mud, spent cathode carbon blocks, and carbide slag. The coupling reaction mechanism of the valuable or toxic components of aluminum, sodium, silicon, calcium, iron, fluorine, and nitrogen in the industrial wastes was studied in order to explore the potential value of waste. The results show that the alumina and sodium components in the industrial wastes are efficiently extracted, and the reaction process is promoted by iron and carbonaceous substances. The hazardous solid waste aluminum dross and the spent cathode carbon block are detoxified during the reaction process. The optimal reaction temperature is 1150 °C, and the residence time is 45–75 min. The extraction rate of Al2O3 is 92.4–93.3%, and the extraction rate of Na2O is 93.5–94.4%. The extracted alumina and sodium components can be used to prepare a series of high quality alumina.