Recovery Of Valuable Components Research Articles

Siyah Havuç Suyu Atıklarından Selüloz Ekstraksiyon Parametrelerinin Optimizasyonu ve Nanoselüloz Üretimi

Agricultural wastes are abundant worldwide with increased production and consumption activities as a result of human population growth. Waste recycling processes, which are important to support sustainable production, remain popular due to the increasing amount of agricultural waste. In particular, there are various studies on the recovery of valuable components from waste. In this context, the recovery of cellulose and nanocellulose from waste, which has the potential to be used and applied in many sectors, especially in food, draws attention. Although black carrot juice waste, which is one of the important agricultural wastes, is frequently used in the production of natural colorants, it was used for the production of cellulose and nanocellulose in this study due to its high cellulose content. Response Surface Method-Central Composite Design was used to improve the alkaline extraction conditions of cellulose for the optimum yield and whiteness index by using process parameters of NaOH concentration (2–12%), process temperature (25–110 °C), and time (60–240 min). The optimum process parameters were determined as the NaOH concentration (7.06%), process temperature (44.83°C), and time (114.21 min) for alkaline extraction of cellulose from black carrot juice waste where the yield of cellulose was 22.90±2.48%, and whiteness index was 60.32±0.07%. Nanocellulose was produced from cellulose obtained from black carrot juice waste by acidic hydrolysis using 25% H2SO4. Nanocellulose yield and whiteness index were found as 15.76±0.16% and 58.77±0.26% respectively. The average diameter (61±2.89 nm) and length (281±18.50 nm) of the nanocellulose were determined by Atomic Force Microscopy (AFM). As a result of the Fourier Transform Infrared (FTIR) spectroscopy, it was determined that non-cellulosic components were removed.

Increase in Recovery Efficiency of Iron-Containing Components from Ash and Slag Material (Coal Combustion Waste) by Magnetic Separation

This article presents the results of research aimed at optimizing the process of recovery of valuable components from ash and slag waste from thermal power plants. In this work, both experimental and theoretical studies were carried out to substantiate the use of magnetic separation methods for ash and slag waste processing. Ash and slag wastes were chosen as an object of research due to the presence of valuable components such as iron, aluminum, etc., in them. The research results showed that the method of magnetic separation, including high-gradient magnetic separation, can be effectively used in ash and slag waste processing. As a result, the topology of a magnetic beneficiation technological scheme has been proposed to obtain high-value-added products such as high-magnetic iron minerals, low-magnetic iron minerals, and aluminosilicate microspheres. By using magnetic separation in a weak magnetic field, magnetic microspheres containing high-magnetic iron minerals associated with intermetallics, ranging in size from 20 to 80 µm, were recovered. In the second stage of magnetic separation (high-gradient magnetic separation), an iron ore product with an iron content of 50% with a recovery of 92.07% could be obtained. By using scanning electron microscopy, it was found that the main part of microspheres, which contain low-magnetic iron minerals and aluminosilicates, with sizes from 2 to 15 microns, was recovered in the magnetic fraction. This paper proposes a new approach to the enrichment of ash and slag materials using magnetic separation, which will increase the efficiency of their processing and make the process environmentally sustainable.

Recycling of end of life photovoltaic solar panels and recovery of valuable components: A comprehensive review and experimental validation

With the current rate of installation of photovoltaic (PV) modules, the total installed capacity is expected to reach 4500 GW by 2050. Given the average life of solar modules is 25 years, after their spent time the installed solar panels will eventually turn into waste. The waste from solar panel modules is expected to reach about 8600 tons by 2030 and it will further increase to 78 million tons by 2050. The waste solar panel should be discarded or recycled appropriately since the toxic substances released from them can affect human health and the environment. Therefore, there is a need to develop a recovery and recycling process for waste produced from solar modules. In this comprehensive work, we have summarized (i) the classification of photovoltaic technology, (ii) review the approaches embraced for photovoltaic (PV) waste management on a global level, (iii) the need for photovoltaic (PV) waste management and brief explanation on the recycling process (Mechanical, thermal, chemical and leaser methods) of solar cells. Also, experimental validation has been provided by the recovery of discrete components from End of Life (EoL) solar panels in an appropriate amount. The recovered material components from the modules were subjected to structural and chemical characterization to attest phase purity of the samples.

Some Characteristics of Thermodynamic Systems and Their Effect on the Efficiency of the Recovery of Valuable Components of Industrial Wastewater from PAO Kazanorgsintez by Supercritical Fluid Extraction

Some Characteristics of Thermodynamic Systems and Their Effect on the Efficiency of the Recovery of Valuable Components of Industrial Wastewater from PAO Kazanorgsintez by Supercritical Fluid Extraction

Metabolic Stability of Eight Airborne OrganoPhosphate Flame Retardants (OPFRs) in Human Liver, Skin Microsomes and Human Hepatocytes

The waste of electrical and electronic equipment (WEEE) is generally considered a secondary raw material for the recovery of valuable components. However, emerging issues regarding the impact of suspended particles arising from WEEE recycling operations are a concern. It was recently demonstrated that samples from three different WEEE plants were rich in organophosphate flame retardants (OPFRs). Since exposure to a xenobiotic can lead to its biotransformation through human metabolism routes, in the present study, the metabolism of eight OPFRs of interest in our sampling campaign (triphenyl phosphate (TPhP), tri-m-tolyl phosphate (TMTP), ethylhexyl diphenyl phosphate (EHDPhP), tributoxyethyl phosphate (TBOEP), diphenyl phosphate (DPhP), trichloroethyl phosphate (TCEP), tris(1,3-dichloropropan-2-yl) phosphate (TDClPP) and bisphenol A bis(diphenyl phosphate) (BDP)) was investigated. Their metabolism was studied at different time points in three matrices: human liver microsomes, human hepatocytes and human skin microsomes. This study, which was run using a common experimental setting, allowed easy comparison of results for each OPFR of interest, and a comparison with other data in the literature was performed. In particular, a number of metabolites not previously described were detected, and for the first time, it was shown that TPhP could be metabolized in human skin microsomes.

The recovery of valuable components from secondary lead dust by a multi-step hydrometallurgical process

Multicomponent secondary lead dust (MSLD) is a significant resource that contains valuable metals such as lead, zinc, and cadmium, along with potentially harmful components such as salts (K, Cl) and As. In this study, an economic and efficient method was proposed for the recovery of MSLD, including desalination, sulfation roasting, water leaching, and zinc plate cementation. Firstly, desalination was conducted to remove K and Cl, and 90.4% of K and 76.5% of Cl were selectively removed with a low NaOH consumption of 1.00 g/t dust at 40 °C and pH 7.5. Subsequently, the desalted residue, enriched with Cd, Zn, As, and Pb, was treated by H2SO4 roasting, which facilitated the transformation of arsenites and sulfides into As2O3 and sulphates. The recovery of As was achieved with a volatilisation efficiency of 93.2% as As2O3 using 65% H2SO4 at 350 °C. Finally, the recovery of Cd was accomplished through zinc plate cementation, resulting in the cementation of 99.4% Cd as Cd sponge with a purity of 96.3%. The residue from water leaching and cemented solution gathered 98.2% Pb and 94.6% Zn. The multi-step process realised the selective removal of K and Cl salts as well as the comprehensive recovery of valuable elements.

Thermodynamic analysis and application for extracting valuable components from iron-phosphorus residue of spent catalysts

The method of extracting valuable metals from spent catalysts has been developed in recent years. In this paper, the solid waste produced in the treatment of spent catalyst was studied and named iron-phosphorus residue (IPR). IPR was composed of FePO4·2H2O, Fe3(PO4)2·3H2O, Fe5(PO4)4(OH)3·2H2O, and SiO2. Appreciable quantities of Ni, Co, V, Mo, and W were detected in IPR. Based on E-pH diagrams, different atmospheric leaching strategies were used to extract valuable components from IPR. Both the HCl and NaOH leaching are appropriate for treating IPR. An in-depth investigation on HCl atmospheric leaching showed that >95% of Fe, Ni, Co, V, and Mo, 76.9% of W, and 89.3% of P were extracted efficiently and SiO2 was enriched into the leach residue, at leaching temperature of 90 ℃, leaching time of 180 min, initial HCl concentration of 5 mol/L and liquid to solid ratio of 8:1 mL/g. The leaching mechanism was discussed via XRD, XPS, and FTIR. An efficient and green process for the recovery of valuable components in IPR has been developed. This research achieves the sufficient extraction of valuable components in IPR and provides significant guidance for the management of similar solid waste.

Sustainable Selective Recovery of Sulfuric Acid and Vanadium from Acidic Wastewater with Two-Step Solvent Extraction.

A two-stage extraction process was proposed to recover sulfuric acid and vanadium from simulated acid solution and titanium dioxide waste acid (TDWA). Some extractants were compared and studied, in which the enthalpy changes (ΔH) of the extraction process and the extracted complex were analyzed by using thermodynamics. The microscopic characteristics of the loaded organic phase were compared and investigated by infrared spectroscopy (FT-IR), where the extraction mechanism was described. The extraction efficiency of sulfuric acid was more than 99% by three-stage countercurrent extraction with 60% triisooctylamine (TEHA) and 35% N-pentanol, in which ΔH was -61.31 kJ/mol and the extracted complex of H2SO4·TEHA·2-N-pentanol was obtained. The extraction efficiency of vanadium was above 98% by using 20% bis-2-ethylhexyl phosphate (P507) and 80% sulfonated kerosene, where ΔH was 14.69 kJ/mol and the extracted complex of VO·2A (vanadium as VO2+ and P507 as HA) was obtained. The stripping efficiencies of sulfuric acid and vanadium were more than 90% and 98%, respectively. The extraction effect of used organic phase after regeneration was equivalent to that of the new organic phase with cycle numbers of less than 10. The real waste acid of TDWA was operated to extract and separate sulfuric acid and vanadium with the same parameters, in which the characteristics of high extraction efficiency and good selectivity were obtained. The technique may provide a new thinking for the separation and recovery of valuable components from TDWA.

Chemical and Microbiological Techniques for Recovery and/or Removal of Elements from Incinerated Sewage Sludge Ash—A Review of Basic Methods

In the face of material shortages, growing environmental awareness, and technical advancement, incinerated waste materials are being considered secondary resources. Especially incinerated sewage sludge ash is of interest due to its massive and increasing production and relatively stable composition with a satisfying concentration of elements of value. This paper revises the basic methods for recovery of valuable components from incineration sewage sludge and simultaneous removal or stabilization of elements that may negatively influence the environment with further ash usage or storage. The presented work focuses on collating and analysing the efficiency of currently used approaches as well as their limitations and perspectives for future development. Chemical methods analysed include acidic and alkaline leaching, chelating, and sequential leaching. Due to scarce examples from literature, the exploration of a microbiological approach focuses on the mechanisms and potential for application of different microorganisms for element extraction. The methods described are relatively efficient and affordable, yet still need further development. Specifically, microbiological approaches are rarely used for incineration sewage sludge treatment regardless of their potential advantages over other approaches. Constant mineral and chemical composition within one incineration plant can vary among plants due to many factors, so a well-established range of techniques and an individual approach are important.

High-value utilisation of PGM-containing residual oil: Recovery of inorganic acids, potassium, and PGMs using a zero-waste approach

Residual oil containing platinum group metals (PGMs), which is under-researched, can easily pose resource waste and environmental risks. PGMs feature as scarce strategic metals, and inorganic acids and potassium salts are also considered valuable. An integrated process for the harmless treatment and recovery of useful resources from residual oil is proposed herein. This work developed a zero-waste process based on the study of the main components and characteristics of the PGM-containing residual oil. The process consists of three modules: pre-treatment for phase separation, liquid-phase resource utilisation, and solid-phase resource utilisation. Separating the residual oil into liquid and solid phases allows for the maximum recovery of valuable components. However, concerns about the accurate determination of valued components emerged. Findings revealed that Fe and Ni are highly susceptible to spectral interference in the PGMs test when using the inductively coupled plasma method. After studying 26 PGM emission lines, Ir 212.681 nm, Pd 342.124 nm, Pt 299.797 nm, and Rh 343.489 nm were reliably identified. Finally, formic acid (81.5 g/t), acetic acid (117.2 kg/t), propionic acid (291.9 kg/t), butyric acid (3.6 kg/t), potassium salt (553.3 kg/t), Ir (27.8 g/t), Pd (10960.0 g/t), Pt (193.1 g/t), and Rh (109.8 g/t) were successfully obtained from the PGM-containing residual oil. This study provides a helpful reference for the determination of PGM concentrations and high-value utilisation of PGM-containing residual oil.

Gallium and other valuable components recovery from phosphorus flue dust by a novel process combining vacuum chlorination and water leaching

Gallium (Ga) is an important strategic metal widely used in the semiconductor manufacturing industry. In this paper, a new vacuum chlorination and water leaching process for simultaneous P fixation and Ga, Pb, and Zn separation from phosphorus flue dust (PFD) using CaCl2 as reagent was proposed. The principle of metal volatilization in vacuum was clarified and the reaction mechanism of chlorination was studied. The impacts of the experimental parameters on the metals volatilization rate were assessed. Under the optimal conditions, Ga volatilization rate reached 97.44 %, the volatilization rates of Pb and Zn respectively reached 98.11 %, and 98.56 % and were highly enriched in the condensation zone, while most of P was converted into water-insoluble Ca2P2O7 and remained in the residue. In addition, the impacts of several factors in the water leaching process on the removal of Cl from the residue were studied. Finally, the leaching solution mainly containing Cl-, K+, and Ca2+ and the water leaching residue with P content of 19.21 % were obtained. This process provides a new clean and sustainable method for the recovery of valuable components in PFD, without the generation of hazardous substances, and therefore it has potential application value.

Hydrogarnet process as a modern approach to hydrometallurgical alkaline processing of low-grade bauxites. Review

In current conditions, energy costs are becoming the decisive factor threatening the existence of alumina industry. Hydrochemical processes are relevant for low-grade bauxites and red muds as, due to high availability of such materials (as compared with the high-grade ones), a critical rise of energy costs (gas, fuel oil, coal) can be offset when relying on the conventional Bayer process. This paper considers the results of studies aimed at the development and implementation of Bayer-hydrogarnet process to be applied to low-grade bauxites and dumped red muds. The sodium and aluminium oxides contained in red mud get regenerated in the hydrogarnet cycle and get returned to the Bayer process, while the new solid product synthesized, which carries all the bauxite iron, silicon, calcium and trace elements, is converted into various commodities. The authors demonstrate that, irrespective of the origin of bauxites and red muds, this technology enables to achieve high recovery of valuable components into final products while minimizing pollution. Recent developments concerning the equipment used and the actual process were aimed at streamlining the process, raising the recovery of aluminium oxide and expanding the range of by-products. Apart from producing alumina and aluminium hydroxide, the low-waste hydrogarnet process can be used to produce cast iron, pigments, ameliorants, building materials and others. Tests conducted at different scales prove that the process can be applied to different grades of bauxite.

Suitability of CAD-based Disassembly Sequence Plans for Flexible Remanufacturing

When products reach the end-of-first-life (EoFL), often recovery of valuable components is ignored because of unprofitable disassembly processes. Extracting the wanted component is a highly manual try-and-error process of disassembling multiple components. The creation of dis- and reassembly plans (e.g. for workers or robots) based on CAD files is currently too labour extensive and individually dependent on the EoFL state. Several studies exist for the automatic generation of assembly plans by CAD files with collision-based approaches. However, whether these approaches are suitable for industrial remanufacturing planning has not been discovered. This research compares the suitability of an AND/OR graph (AOG) and a precedence graph (PG) approach on ten exemplary examples. The suitability is measured with graph-based and visual feasibility checks as well as performance measures. The AOG approach is more promising than the PG approach because it considers the flexible formation of subassemblies and thus, better flexibility for scheduling in mixed-model disassembly lines. The results contribute to automatically deriving disassembly and reassembly plans for lot size one and saving labour-extensive high-wage planning effort. Overall, the resulting quality of assembly plans is highly dependent on the CAD model quality. Only two of the ten models resulted in suitable assembly plans. A preliminary CAD quality control during the design phase is needed to improve the applicability of the examined approaches.

Functional Oligosaccharides Derived from Fruit-and-Vegetable By-Products and Wastes

Industrial-scale food manufacturing generates high quantity of fruit-and-vegetable solid by-product and waste streams (FVSW) which have become a challenge to the environment post-production. Due to this, proposals for a better use of resources to reduce the environmental burden and to promote a circular economy have been introduced. Reintroducing discarded materials back into the production through the recovery of valuable components or through the conversion into value-added ingredients is one approach attracting strong interest in research. FVSW is rich in lignocellulosic materials which can be reused to produce bioactive ingredients. This review highlights the potential use of FVSW as low-cost raw materials and describes the valorisation of FVSW for the production of functional oligosaccharides. The focus is on the production technologies of the main functional oligosaccharides, namely pectic-oligosaccharides, inulin and fructooligosaccharides, xylooligosaccharides, and isomaltooligosaccharides.

Manufacture of wear-resistant cast iron and copper-bearing antibacterial stainless steel from molten copper slag via vortex smelting reduction

A novel method of preparing wear-resistant cast iron and copper-bearing antibacterial stainless steel by moderate dilution of molten copper slag and vortex smelting reduction is proposed in this paper. The reduction behaviors of different components during vortex smelting reduction after medium dilution of molten copper slag are systematically investigated. Thermodynamic analysis results show that lime (CaO) can promote the decomposition of the iron peridotite phase and strengthen the reduction of copper and iron in slag. Under the conditions of 1450 °C, slag alkalinity of 1.0, 0.13 wt% carbon addition, vortex stirring speed of 250 rpm, and sedimentation stirring speed of 63 rpm, the metallization rate of copper and iron is 91.76%. In addition, 97.90 wt% zinc and 14.79 wt% lead in copper slag enter flue gas to be recovered, and 94.11 wt% silver and 88.66 wt% gold are reduced into metal. HBW555Cr13 wear-resistant cast iron and 20Cr13Cu3 copper-bearing martensitic antibacterial stainless steel, which meet the requirements of Chinese national standards, are successfully prepared by this process, realizing the separation, enrichment, and recovery of valuable components in the copper slag. The Brinell hardness of wear-resistant cast iron is 575, and the antibacterial rate of copper-containing antibacterial stainless steel against Escherichia coli is more than 99%. The reduction slag can be used as the raw material for preparing cement clinker after water quenching. There is no secondary waste residue, which realizes the molten copper slag's large-scale, slag-free, and high-value utilization.

Functional properties of extracts from wheat ( Triticum aestivum L.) coarse bran and shorts (razmol) obtained under different supercritical CO 2 extraction conditions

Coarse bran and shorts (razmol) are by-products of wheat milling. The important functional and bioactive components of wheat are separated during milling along with the bran and razmol. Supercritical CO2 extraction process is an environmentally friendly application that is used effectively in the recovery of functional and bioactive components. In this study, the functional components of the extracts obtained by supercritical CO2 extraction at different pressures from wheat bran and razmol were investigated and compared. It was found that the total phenolics content and antioxidant activity of razmol extracts increased with the increase of applied pressure. It was determined that the total polyunsaturated fatty acid content of the bran extracts increased from 55% to 59% with the increase in pressure, however, there was no significant change in the razmol extracts and it was around 57%. It was observed that the FTIR spectra of the extracts obtained by supercritical CO2 extraction of wheat bran and razmol were similar to the spectra of edible vegetable oils and wheat germ oil. However, in the obtained spectra, it was determined that CO2 peaks occurred at 2357 cm−1 with the application of supercritical CO2 extraction. Apart from this, differences were observed in the fingerprint region due to the fact that the extracts contain different bioactive compounds. The change in pressure applied in supercritical CO2 extraction caused changes in the extract profiles. In addition, in this study, it was determined that bran and razmol extracts were different in terms of extract yield and amount of bioactive components. Practical applications In the milling industry, a significant amount of bran and razmol are separated as by-products. This study provides guidance on the recovery of valuable components from these by-products with an inexpensive and environmentally friendly application. In addition, by revealing the functional properties of the extracts obtained, it helps to evaluate their possible use in the food industry.

A closed-circuit cycle process for recovery of carbon and valuable components from spent carbon cathode by hydrothermal acid-leaching method.

Spent carbon cathode (SCC) as a hazardous solid waste produced in aluminum electrolysis industry, contains plenty valuable components but generate a seriously threat to the environment. This paper focus on a closed-circuit cycle process for direct treatment of SCC based on the hydrothermal acid-leaching method. Thermodynamic calculation, single factor experiment, orthogonal experiment and kinetic study are utilized to obtain the leaching properties of impurities, optimize the leaching conditions, study the influence of conditions on leaching, and capture the restriction factors of leaching. The results indicate that the carbon content of the treated SCC can reach 97.3% when the leaching condition attach the optimal (liquid-solid ratio of 25mL/g, temperature of 413K, time of 270min and acid concentration of 4mol/L), and liquid-solid ratio is regarded as the crucial factor influencing on that. In addition, the activation energy of impurities reaches 6.25kJ/mol and the whole leaching process is controlled by the diffusion extent. Finally, the filtrate after the hydrothermal acid leaching is treated, and calcium fluoride, cryolite and sodium chloride are successfully separated. The proposed process eliminates the harm of SCC to the environment, and completes a closed-circuit cycle for the treatment of SCC and recovery of valuable components. It enriches the hydrometallurgical processes of SCC, and provides an attractive scheme for the treatment of SCC.

Efficient recovery of aromatic compounds from the wastewater of styrene monomer and propylene oxide co-production plant via hypercrosslinked aryl-rich starch-β-cyclodextrin polymeric sorbent

• A hydrophilic HSPS-ACD(H) with high porosity was fabricated. • HSPS-ACD(H) is a new benchmark sorbent for uptake of AP and 1-PE. • Competitive or synergetic adsorption of co-existing aromatics was studied. • Efficient recovery of the target aromatics was demonstrated in fixed bed column. • DFT calculations provided insights into mechanism for selective adsorption. Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge. Herein, we develop an efficient continuous adsorption process for recovering aromatic compounds in wastewater from styrene monomer and propylene oxide co-production (SMPO) plant. Based on our insight into the potential of bio-based porous materials for adsorption application, starch-graft-polystyrene (SPS) and aryl-modified β-cyclodextrin (ACD) were prepared, and novel hypercrosslinked porous polymers combined SPS with ACD (HSPS-ACDs) were synthesized through external crosslinking approach. In a binary-component system, the best-performing one HSPS-ACD(H) with high ACD content and large specific surface area possessed superior capacities for the representative aromatic compounds, acetophenone (AP, 2.81 mmol·g −1 ) and 1-phenylethanol (1-PE, 1.35 mmol·g −1 ) compared with the previously reported materials. Further, the adsorption properties of aromatic compounds on HSPS-ACD(H) were investigated in batch mode. For practical application, continuous adsorption experiments were conducted in a HSPS-ACD(H)-packed fixed bed, where the target aromatic components in wastewater were effectively retained and further released by elution. Besides showing the reversible adsorption and efficient enrichment effect, the HSPS-ACD(H)-packed fixed bed also maintained great stability in multiple cycles. Moreover, quantum chemical calculations were performed to elucidate the potential mechanism of adsorption of AP and 1-PE onto HSPS-ACD(H).

Study on the Electrochemical Mechanism of the Comprehensive Recovery of Valuable Components from Spent Cemented Carbide

Study on the Electrochemical Mechanism of the Comprehensive Recovery of Valuable Components from Spent Cemented Carbide

Optimization of Conditions for Processing of Lead–Zinc Ores Enrichment Tailings of East Kazakhstan

This article presents the results of studies of a low-waste technology for processing enrichment tailings using a combined enrichment–hydrometallurgical method. After washing the enrichment tailings from harmful products and reducing their size, multi-stage flotation of the crushed material of the enrichment tailings was carried out. The use of a new reagent in the flotation process was studied in order to ensure the maximum recovery of the main valuable components from the enrichment tailings. A new collector of Aero 7249 (Shenyang Florrea Chemicals Co., Ltd., Shenyang, China) type was used for the flotation. The recovery of valuable components was as follows: Cu, 6.78%; Zn, 91.69%; Pb, 80.81%; Au, 95.90%; Ag, 82.50%; Fe, 78.78%. Tailings of the flotation were re-enriched using a fatty acid collector (sodium oleate). Additional (reverse) flotation resulted in obtaining a product corresponding to the composition of building sand in terms of the content of valuable components of the waste rock. The studies of the conditions for processing the enrichment tailings of lead–zinc ore indicate the possibility of its optimization in order to maximize the involvement of waste in the production.