Environmental Protection Requirements Research Articles

Trimetallic MOF–derived Fe–Mn–Sn oxide heterostructure enabling exceptional catalytic degradation of organic pollutants

Developing efficient and environmentally benign heterogeneous catalysts that activate peroxymonosulfate (PMS) for the degradation of persistent organic contaminants remains a challenge. Metal–organic frameworks (MOFs)–derived metal oxide catalysts in advanced oxidation processes (AOPs) have received considerable attention research fraternity. Herein, we report an innovative magnetic trimetallic MOF-derived Fe-Mn-Sn oxide heterostructure (FeMnO@Sn) with adjustable morphology, size and Sn content, prepared through an impregnation–calcination strategy. The formation of a novel magnetic Fe2O3/Fe3O4/Mn3O4 heterostructure induces the generation of abundant Fe2+ and Mn2+ sites on the FeMnO@Sn surface. Meanwhile, the introduction of SnO2 into the Fe2O3/Fe3O4/Mn3O4 heterostructure facilitates the cleavage of the OO bond in adsorbed PMS. The synergy among the different functionalities of each metal oxide plays a vital role in the swift and effective degradation of pollutants. In addition, the uniquely designed catalyst exhibits magnetic properties that facilitate easy recycling and repeated use, thereby meeting environmental protection requirements. Overall, this research highlights the design of heterogeneous catalysts for the effective activation of PMS and provides valuable insights for the advancement of future environmental catalysts.

Smart Product-Service System for Parking Furniture—Sale of Storage Space in Parking Places

Growing competition, changing customer needs, and growing environmental protection requirements mean companies are forced to change their approach to business. Traditional product sales are being replaced by systemic solutions focused on meeting specific customer requirements while reducing negative impacts on the environment. One such solution is the Product-Service System (PSS). This allows manufacturers to offer their products’ functionalities and features through related services. By extending the life of products, promoting the reuse of materials, and reducing the amount of waste, the implementation of PSS strongly supports sustainable development. The paper focuses on a new product group—garage boxes (GB). It discusses a new PSS business model that responds to the needs of people living in blocks of flats with no tenant storage lockers or rooms in the basement. The new business model sells the function (storing various possessions) and eliminates problems faced by tenants due to the lack of sufficient storage space. It provides customers with high-quality GB for as long as they need them. Customers can pick and choose equipment with additional services depending on their needs. The idea of the model is the outcome of a nationwide study carried out in Poland on a group of 500 residents of blocks of flats and consultations with manufacturers, homeowner associations, wholesale and retail traders, and the financial sector. The study provided us with information and data that provided a comprehensive picture of the problem of the absence of storage lockers or rooms for residents and the needs connected with GB. The results of the conducted research indicate that the developed business model responds to the diverse requirements of residents and supports sustainable solutions. It is an alternative to the lack of a storage unit assigned to each apartment. The business model developed in the paper is highly innovative and comprehensive. This makes it an attractive solution for residents of apartment blocks, and its implementation can significantly reduce the environmental impact.

Promising areas of slag processing in ferrous metallurgy

The characteristics of promising areas of slag processing in ferrous metallurgy are given. An increase in requirements for environmental protection was noted. Modern slag processing includes primary and secondary processing, which differ in the physical state of the slag. The technological foundations of mass processing of slag have been formed at the Ural Institute of Metals. An assessment of the state of slag processing shows that the capacity of crushing and screening plants, mainly due to complexes purchased abroad, exceeds the yield of slag of current production and leads to a decrease in dumps. Modern areas of economics and environmental protection require the creation and implementation of new technologies and equipment for the processing of slag in liquid and solid form, improving the quality of products at all stages of processing. Processing of slag in liquid form at furnace (or located near melting furnaces) plants will make it possible to organize the technological process in highly economical environmentally friendly small-sized units, to adjust the composition and properties of slag, to expand the range and quality of the resulting products, to create conditions for the utilization of melt heat and the recycling of slag processing products. These processes reduce the environmental burden on the environment, reduce material, energy and operational costs, and expand the range and quality of the products obtained

Evaluation of Biosurfactants to Preflush for Offshore Wells.

With the improvement of environmental protection requirements in offshore oil and gas exploration, there is a great demand to find environmentally friendly surfactants for cementing preflush fluids. In the present paper, the application potential of three biosurfactants of rhamnolipid, lipopeptide, and sophorolipid in the preflush fluid was evaluated through a series of experiments. The experiments studied the interfacial tension (IFT) of the biosurfactants, resistance to temperature, salt resistance (sodium chloride and sea salt), and the influences of the studied biosurfactants on the rheological compatibility and capabilities to convert the wettability of the formation from oil-wet to water-wet, mud cake removal efficiency, and to improve the interfacial bonding properties of the preflush fluid. The results showed that rhamnolipid, lipopeptide, and sophorolipid exhibited excellent surface activities in high-temperature and sodium chloride (NaCl) environments. When exposed to sea salt, lipopeptides lost their function due to agglomeration, while rhamnolipids and sophorolipids maintained structural stabilities and high surface activities. When rhamnolipid was mixed with sophorolipid in a ratio of 2:1 at the same concentration, the combined biosurfactant had the best surface activity among the studied surfactants. The combined biosurfactant not only had good rheological compatibility with the drilling fluid and cement slurry but also showed excellent properties in the removal of mud cake. In addition, the effect of the removal of the mud cake was verified by the gas channeling experiment. The experimental results show that the presence of mud cake can reduce the bonding strength. When rhamnolipid was mixed with sophorolipid in a ratio of 2:1 at the same concentration, the removal efficiency of mud cake was the highest, and the interfacial bonding property of the cement sheath can be improved.

Studying the Characteristics of Tank Oil Sludge

Oil sludge is one of the main pollutants generated by the oil industry. Due to serious pollution and increasing oil production, problems arise every year in the effective treatment of oil sludge. The current study examines the composition and physicochemical characteristics of oil sludge, as well as traditional and new methods for processing oil sludge. With the tightening of environmental protection requirements, oil sludge quality reduction, recycling, and harmless treatment technologies will become necessary in the future. The primary task was to determine the composition of tank oil sludge, separate it from mechanical impurities, and study the influence of ultrasonic treatment and subsequent atmospheric distillation on the extract. The separation of the concentrate and the composition of the tank oil sludge, using an extracted mixture of hexane and benzene, are considered. The use of modern SEM methods, elemental analysis, NMR analysis, IR, ultrasound, and GC–mass spectrometry made it possible to characterize the organic part of reservoir oil sludge and its distillation products. First, 300 g of tank oil sludge was preheated and mixed with 300 mL of solvent (hexane:benzene = 1:1). After mixing with the solvent, the result mixture was filtered. Then, it was placed in an ultrasonic bath and exposed to ultrasound at a frequency of 100 kHz for 30 min. After processing, it was extracted in a Soxhlet apparatus at a temperature of 65 °C to isolate the extract. The resulting extract was analyzed on a gas chromatograph with mass detection. The composition of the extract was as follows (in %): hexane—83.99; total hydrocarbon isomers—7.12; n-hydrocarbons—2.52; benzene—6.37%. At a temperature of 85 °C, the benzene yield was 65.85%. It has been established that the fractions obtained through the distillation of oil sludge at temperatures of 65–85 °C have improved dissolving capacity. It has also been shown that the use of these fractions promotes an increase in the content of hydrocarbon isomers by 12–13% in the extract composition.

Trends and drivers of land abandonment in Poland under Common Agricultural Policy

The results of existing research predict that the area of abandoned land will increase in many European regions. One of the countries that are the most prone to this process is Poland where agriculture, after many transformations, is still an important sector of the economy. It is essential to determine drivers of the abandonment of agricultural land use in order to effectively counteract this process. Through the Common Agricultural Policy, the European Union financially supports farmers who use agricultural land in accordance with the environmental protection requirements. This study investigated to what extent the land use, the characteristics of agricultural holdings, the demographics as well as economic factors impacted the process of land abandonment in Poland during the period 2002–2020. The analysis was carried out using statistical and spatial data pertaining to the period before and after Poland’s accession to the European Union. Our results demonstrate that the share of abandoned land within the country's agricultural area has decreased from 9.7 % to 1.2 %. Direct payments to farmers and the agrarian structure of farms were the most significant factors affecting this process. Spearman’s rank order correlations between the share of abandoned arable land and the two mentioned variables are close to or higher than 0.5 in each analysed year. The obtained results did not confirm the common conviction that environmental factors play a decisive role in the process of cultivation abandonment.

Оценка эффективности завихрения воздуха при распылении водоугольных суспензий пневматической форсункой

Due to modern requirements for environmental protection, introduction of environmentally friendly power engineering technologies involves search and development of new energy sources. One of the ways to meet these requirements and maintain the same level of energy production by thermal power plants is to use multicomponent fuels. The most promising and affordable heavy fuel oil from the point of view of energy, ecology and economy are coal-water slurries (CWS). In this regard, the study of the properties and characteristics of such fuels is relevant. The coal-water slurries have been prepared in a rotary hydrodynamic cavitation generator. A pneumatic atomizer with external mixing is used to spray the coal-water slurries. Interferometric Particle Imaging method is used to determine the average size of fuel droplets after atomization. The authors have conducted experimental studies of the characteristics of atomization of coal-water slurries based on lignite and pyrogenetic liquid with a pneumatic atomizer with a tangential supply of a spraying agent. A three-stage method to prepare lignite-based slurries with pyrogenetic liquid has been tested. It has been established that when using this technique, the fluidity of coal-water fuel is maintained even with the introduction of 20 % by weight of pyrogenetic liquid into the composition of coal-water slurries when replacing both water and coal in equal proportions. The kinematic viscosity of coal-water suspensions increases when pyrogenetic liquid is added, despite a decrease in the concentration of the solid component. The change of suspension density is insignificant. The results of the study of atomization process have shown that the tangential air supply to the atomizer leads to an increase of the jet spraying angle by 6° compared with direct supply. At the same time, the average droplet size in the jet of a two-component CWS with direct air supply is 8 % smaller. The results of the study have made it possible to obtain completely new knowledge that can significantly advance domestic and world science and technology in the field of power engineering, namely the technology of coal-water fuels atomization. Experimental studies have determined the main patterns of influence of the CWS properties and the method of spraying agent supply on the formation of a gas-drop jet. Such patterns will provide conditions for the effective atomization of quite viscous CWS in the combustion chambers of energy boilers. The results obtained will enable designers and constructors to develop highly efficient designs of steam and hot water boilers and gasifiers fueled by CWS.

Прокурорский надзор за исполнением законов в сфере охраны окружающей среды в Арктической зоне Российской Федерации

Federal executive authorities, the Prosecutor's Office of the Russian Federation, the Environmental Prosecutor's Office of the Arctic Zone of the Russian Federation (AZRF) pay special attention to the state of the Arctic environment. However, the situation in this region is far from normal. The results of the prosecutor's inspections indicate the presence of numerous violations of environmental legislation in the field of subsoil use, marine and river transport, construction, land use and reclamation, and the elimination of accumulated damage as a result of past years. There are cases of industrial safety violations. A serious problem for the Arctic regions is the lack of an effective waste management system in the Arctic zone. Global warming and disruption of the Arctic environment leads to climate change and can lead to even more tangible and severe environmental consequences. The Environmental Prosecutor's Office has a significant impact on correcting the situation in the Arctic, which conducts inspections of enterprises, organizations and citizens for compliance with environmental legislation, prevents and suppresses environmental offenses, and ensures compliance with environmental protection and environmental management requirements.

Impacts of institutional pressures and internal abilities on green performance of transport and logistics companies

PurposeTransport and logistics companies (TLCs) have adopted green practices to reduce their emission and waste in support of environmental protection requirements. However, not all green practices of TLCs have resulted in green performance (GP) because of inherent variations in internal abilities and external factors affecting firms in different operational environments. Using institutional (INT) and resource-based view (RBV) theories we develop a model that shows how institutional pressures and internal abilities impact TLCs’ GP.Design/methodology/approach Underpinned by INT and RBV theories, this study utilised structural equation modelling on a cross-sectional survey of 222 TLC firms operating in the Philippines.Findings The study reveals that TLCs’ regulatory compliance, social obligations and competitor pressures have significant direct effects on TLCs’ GP while supplier integration and resource capabilities serially mediate the relationships. The findings indicate that institutional pressures and internal abilities that shape firms’ environmental policies and procedures explain TLCs’ GP.Research limitations/implications As a result of the cross-sectional nature of our data, findings may be time, population and prevailing situation dependent. The long-term validity of the research can be improved if longitudinal design is employed. We collected data from a single respondent considered as the best respondent. However, with time and resource availability, a jury of executives for each company would have been a better alternative respondent.Practical implications The findings of this research provide TLC managers, policymakers and other stakeholders with much-needed guidance for crafting policies and strategies for handling the challenges of caring for the planet and maintaining sustainable operations.Social implications Improving green practices of TLCs to enable waste and emission reductions is critical to the health and well-being of people and the planet. An environment free of pollution will result in fewer health challenges, fewer medical/insurance-related expenses, and, above all, enable a higher quality of life and a more productive workforce.Originality/value Studies have extensively explored the green practices of TLCs as well as the influences of both institutional pressures and internal abilities of TLCs on their green practices. This study identifies critical factors that significantly affect the GP of TLCs and provides a conceptual framework for a better understanding of the dynamics of strategic, tactical and operational issues that TCLs may face in their effort at greening the sector.

Waterborne Intumescent Fire-Retardant Polymer Composite Coatings: A Review.

Intumescent fire-retardant coatings, which feature thinner layers and good decorative effects while significantly reducing heat transfer and air dispersion capabilities, are highly attractive for fire safety applications due to their effective prevention of material combustion and protection of materials. Particularly, the worldwide demand for improved environmental protection requirements has given rise to the production of waterborne intumescent fire-retardant polymer composite coatings, which are comparable to or provide more advantages than solvent-based intumescent fire-retardant polymer composite coatings in terms of low cost, reduced odor, and minimal environmental and health hazards. However, there is still a lack of a comprehensive and in-depth overview of waterborne intumescent fire-retardant polymer composite coatings. This review aims to systematically and comprehensively discuss the composition, the flame retardant and heat insulation mechanisms, and the practical applications of waterborne intumescent fire-retardant polymer composite coatings. Finally, some key challenges associated with waterborne intumescent fire-retardant polymer composite coatings are highlighted, following which future perspectives and opportunities are proposed.

Review on Location of Fresh Cold Chain Logistics Distribution Center

This paper reviews the research status, existing problems and challenges, and future research directions of the location of fresh cold chain logistics distribution centers. The research background is based on factors such as the development of the fresh product market, the technological progress of cold chain logistics, the requirements of environmental protection and sustainable development, and the intensification of market competition. The significance of site selection includes improving transportation efficiency, reducing costs, improving customer satisfaction, optimizing supply chain networks, and achieving environmental sustainability.The former focuses on low-carbon, demand uncertainty, and competitive distribution center location, while the latter focuses on the new retail environment and cold chain distribution. The review of relevant literature points out that some progress has been made in the research, but there are challenges such as market demand uncertainty, incomplete data and limited model applicability.Future research directions include the location model of cold chain logistics distribution center based on big data, the location model considering sustainable development factors, and the location method of cold chain logistics distribution center integrating multi-index evaluation.In the conclusion, it is pointed out that in the past, the time window and the overall logistics network were rarely used as research evaluation indicators in the site selection problems, and the cost of reverse logistics and closed-loop supply chain was rarely considered. In the prospect part, it is proposed that in the future, we should pay attention to the problems of reverse logistics and closed-loop supply chain in the distribution of fresh agricultural products, consider the multi-objective optimization of low-carbon cold chain logistics network in different policies and fields, and combine full simulation technology and optimization technology to realize the system optimization research.

Advanced orthogonal analysis of multi-factorial interactions influencing co-combustion performance and pollution reduction potential of coal gangue and biomass in oxy-fuel combustion conditions

In the current scenario of increasing energy scarcity and stricter environmental protection requirements, the utilization of coal gangue and biomass energy is gaining attention worldwide. Biomass and coal gangue are complementary in nature, and their co-combustion can improve the burnout efficiency of coal gangue and reduce pollutant emissions. In this study, coal gangue and wheat straw are selected as research subjects, the optimal process conditions for their co-combustion under the coupling of multiple parameters in oxy-fuel atmosphere through orthogonal experiments are investigated. The results indicate that the most significant factor influencing combustion characteristics is the heating rate. When the biomass content is 45 %, O2 concentration is 50 %, heating rate is 30℃/min and particle size is 180–250μm, the flammability and comprehensive combustion indexes of the samples are maximized, which indicates the optimum combustion characteristics. The primary factor affecting pollutant release is biomass content. When the biomass content is 45 %, O2 concentration is 75 %, combustion temperature is 700℃, and particle size is 180–250μm, the pollutant release concentration is minimized.

The influence of exploration activities of a potential lithium mine to the environment in Western Serbia

The proposed exploitation of the Jadar Valley lithium/borate deposit in Serbia, by the Rio Tinto Corporation, indicates that it would become large-scale processing of boron- and lithium-containing ore. It would be one of the world’s very first lithium mines in populated and agricultural area. The company claims that the envisioned mining will be in accordance with environmental protection requirements. The Jadar Valley deposits have been claimed to cover 90% of Europe’s current lithium needs. Yet, local opposition to the mining has arisen due to potential devastating impacts on groundwater, soil, water usage, biodiversity loss, and waste accumulation. Research drilling by the mining company has already produced environmental damage, with mine water containing high levels of boron leaking from exploratory wells and causing crops to dry out. Furthermore, our investigations reveal substantially elevated downstream concentrations of boron, arsenic, and lithium in nearby rivers as compared to upstream regions. Additionally, here we show that soil samples exhibit repeated breaches of remediation limit values with environmental consequences on both surface and underground waters. With the opening of the mine, problems will be multiplied by the tailings pond, mine wastewater, noise, air pollution, and light pollution, endangering the lives of numerous local communities and destroying their freshwater sources, agricultural land, livestock, and assets.

Ablation simulation of integral woven gradient three‐dimensional thermal protection structures for planetary exploration

AbstractFor the harsh entry environment and higher thermal protection requirements, two structures of three‐dimensional woven gradient thermal protection materials were designed and prepared with the deep space exploration thermal protection system as the object. They are 3D orthogonal woven, 2.5D layer‐to‐layer angle interlock woven, 2.5D layer‐layer angle interlock woven structure(OLL) composite and 3D orthogonal woven, angle 2.5D layer‐to‐layer angle interlock woven, honeycomb structure(OLH) composite. Two materials were prepared and examined by ablation in an oxygen‐acetylene flame. A three‐dimensional macroscopic ablation model was established on the basis of the experiment, and the model was verified to be accurate and effective, which can well respond to the pyrolytic ablation process of the materials. The two designed materials are applied to the outsole of MSL by simulation, and the three‐dimensional response during the entry into Mars is simulated and analyzed in comparison with the thermal protection performance of PICA material. Both materials show better thermal protection than PICA and can be used as a reference in the selection of thermal protection materials.Highlights Two kinds of 3D gradient woven thermal protection materials are designed. A 3D thermal protection system response model is established. The three‐dimensional response during entry was analyzed. Thermal protection of the material is superior to that of PICA.

Optimization of scale inhibitor and adsorption enhancer during squeeze process in offshore oilfields

To solve the problem that scale in oilfields can lead to a reduction of formation permeability and blockage of wellbore and production system pipelines, through the scale inhibitor-formation water compatibility experiment and the minimum effective scale inhibitor concentration experiment, three different types of surfactants are selected as adsorption promoters. Three different types of surfactants were selected as adsorption–desorption accelerators through dynamic core adsorption–desorption experiments. The results of the indoor experiment show that the three types of scale prevention agents selected can meet the environmental protection requirements of the sea area. The static scale prevention rate at high temperature (>120 °C) exceeds 80%, and the minimum effective concentration is less than 3.5 mg L−1. The preferred cation Gemini surfactant has a stable adsorption enhancement effect of the scale inhibitor under different water-bearing conditions and can effectively extend the squeezing life under complex formation conditions. The results improve the comprehensive economic benefits of the field and provide technical feasibility to significantly improve the scale prevention efficiency of the field.

Research on the Performance and Application of a Low-Carbon Waste-Recycling Cement

This paper mainly introduces the history of the formation and development of an ultra-high performance low-carbon waste-utilizing cement (fast-setting and fast-hardening high-belite sulphoaluminate cement). This cement not only uses a large amount of solid waste (fly ash, blast furnace slag, industrial waste gypsum, alkali slag, etc.) as raw materials, and the waste utilization can reach 40%~95%, but also has a calcination temperature of 150~200℃ and 50 ℃ lower than that of traditional ordinary Portland cement and sulphoaluminate cement, and the carbon emission is equivalent to 30%~60% and 50%~80%. Through the elaboration of its main mineral composition, chemical composition, physical properties and action mechanism, the reasons for its excellent properties such as good whiteness, fast setting and hardening, high late strength, and small dimensional deformation are analyzed. And the application research is focused on the fields of inorganic flooring, airports, road quick repair, prefabricated walls, ultra-light and efficient A-level fire insulation, cement crafts, inorganic artificial stone, and UHPC ultra-high performance concrete. At present, there are many types of low-carbon cement in the world, including Porsol cement, Alinit cement, Celitement cement, Japanese eco-cement, multi-component high-mixture cement, high-belite cement, Anther cement, BCT cement, etc., but most of the products have a slow coagulation and hardening speed, and cannot meet the needs of rapid demolding, turnover, and traffic opening for mortar, concrete, cement products or pavements; at the same time, the production process is complicated and cumbersome, the later strength is low, the deformation is large, and the durability is poor. Therefore, in the actual promotion process in the engineering field, there are great difficulties and many constraints. Among them, Aether cement and BCT cement belong to the belite-sulfoaluminate cement system. Aether cement has 6h early strength performance. Compared with Portland cement (burning temperature1400~1500℃), it can significantly reduce production energy consumption, reduce CO2 emissions by 25%~30% per ton of cement, and the 28-day compressive strength reaches the strength level of standard cement (CEMⅠ52.5R); the size shrinkage of this concrete is less than 50% of that of OPC concrete, but its raw materials still use limestone, bauxite, gypsum, iron raw materials and marl raw materials, without effective utilization of bulk industrial waste, and CO2 emissions are far from meeting the low-carbon environmental protection requirements. BCT cement can be produced at a lower temperature (1250~1300℃), and its raw materials use industrial waste residues such as limestone, marl, fly ash and industrial by-product gypsum. CO2 emissions are 30% lower than traditional OPC cement clinker, but there is no early hourly strength, and the strength after 1~2 days is higher than that of ordinary Portland cement. This is far from the goal of using bulk industrial waste as raw materials to produce green, low-carbon, energy-saving and high-performance cement materials, which is currently widely used at home and abroad. At the same time, the above-mentioned low-carbon cement cannot effectively and reasonably control key indicators such as cement whiteness value, early strength before 4 hours, and dimensional change rate, and cannot meet the requirements of high-performance cement. At the same time, the production process is not mature and stable enough, and there is still a long way to go to meet the comprehensive popularization of production industrialization and promotion scale.

Spacer arm of ionic liquids facilitated laccase immobilization on magnetic graphene enhancing its stability and catalytic performance

To fulfill the requirements of environmental protection, a magnetically recoverable immobilized laccase has been developed for water pollutant treatment. In order to accomplish this objective, we propose a polydopamine-coated magnetic graphene material that addresses the challenges associated with accumulation caused by electrostatic interactions between graphene and enzyme molecules, which can lead to protein denaturation and inactivation. To achieve this, we present a polydopamine-coated magnetic graphene material that binds to the enzyme molecule through flexible spacer arms formed by ionic liquids. The immobilized laccase exhibited a good protective effect on laccase and showed a high stability and recycling ability. Laccase-ILs-PDA-MGO has a wider pH and temperature range and retains about 80% of its initial activity even after incubation at 50 °C for 2 h, which is 2.2 times more active than free laccase. Furthermore, the laccase-ILs-PDA-MGO exhibited a remarkable removal efficiency of 97.0% and 83.9% toward 2,4-DCP and BPA within 12 h at room temperature. More importantly, laccase-ILs-PDA-MGO can be recovered from the effluent and used multiple times for organic pollutant removal, while maintaining a relative removal efficiency of 80.6% for 2,4-DCP and 81.4% for BPA after undergoing seven cycles. In this study, a strategy for laccase immobilization by utilizing ILs spacer arms to modify GO aims to provide valuable insights into the advancement of efficient enzyme immobilization techniques and the practical application of immobilized enzymes in wastewater treatment.

The effects of the separator structures and magnetic roller arrangements on eddy current separation

The eddy current separator is the key equipment used for the separation and enrichment of non-ferrous metals from the solid waste. The customization and universality requirements for eddy current separators have been improved with the increasingly strict environmental protection requirements in various industries and the pursuit of higher economic benefits by enterprises. The low separation efficiency of the small-sized non-ferrous metals and the difficulty in separating between non-ferrous metals are two urgent problems that limit the development of the eddy current separation. The separator structures design, the factors regulation and the core component magnetic roller optimization are the keys to solve problems. Vertical and horizontal eddy current separators are the two main types of permanent magnet eddy current separators in practical applications and reported studies. However, the study and production cost of the eddy current separator are high, and there are few reports on the separator structures in existing studies. There is also a lack of comparative analysis of different applicable conditions for eddy current separators and optimization design of the magnetic roller. This study compared and analyzed the effects of different factors on the vertical and horizontal eddy current separation efficiency, and clarified the advantages and prospects of the vertical eddy current separator in optimizing the separation efficiency between non-ferrous metals. The comparison and multi-objective optimization were conducted on the magnetic rollers to expand the particle size range that can be separated. The separation performance and the economy of the magnetic roller have been improved significantly, and the performance indicators are better than those of existing equipment with the same specifications. The magnetic roller with specific structural parameters has increased eddy current force and magnetic efficiency density by 75.0% and 63.5%, respectively. It is expected to further expand the applicable materials for the eddy current separator.

Flotation performance and kinetics study of low-grade limestone with fatty acids-rich oilseed residue as green collector

With the depletion of mineral resources and increasing environmental protection requirements, researching and developing efficient and environmentally friendly flotation agents is crucial for the comprehensive utilization of mineral resources. Low-grade limestone deposits with high impurities pose a challenge for efficient processing and direct industrial applications. This study explores a novel and sustainable approach to address this challenge by evaluating the prospective use of a fatty-acid-rich oilseed residue as a bio-collector (referred to as collector SSFA) to recover carbonates from a low-grade limestone, characterized by high acid insolubles content and its influence on the kinetics of the flotation process. The bio-collector (SSFA) outperformed the conventional collector sodium oleate (referred to as SSO) by significantly increasing the recovery of total carbonates (TC) while simultaneously reducing acid insolubles (AI). A low-grade limestone feed containing 78.40 % TC and 20.90 % AI was upgraded through both mechanical and column flotation techniques. Mechanical flotation yielded a product with 92.9 % TC, 93.48 % TC recovery, 4.0 % AI, and 77.58 % yield at SSFA dosage of 0.87 kg/t. Column flotation, at the same dosage, yielded a product with slightly higher TC content (94.20 %), lower TC recovery (91.02 %), similar AI content (4.07 %), and slightly lower yield (74.68 %). The kinetics of the flotation process indicated that the limestone sample exhibited fast-floating behaviour, attributed to the enhanced selectivity of the SSFA collector. The bio-collector SSFA stands out as a promising and sustainable alternative to conventional collectors for large-scale low-grade limestone flotation due to its remarkable ability to selectively recover total carbonates while minimizing acid insolubles.

Application of Particle Swarm Optimisation in Multi-Objective Cost Optimisation of Engineering Enterprises under the Background of Digital Economy

Engineering projects must meet quality and schedule requirements during construction. This is a typical multi-objective problem and a difficult point in the management of engineering enterprises. To address these issues, a research study proposes an intelligent multi-objective optimisation technique. First, analyse the optimisation objectives of the enterprise in the context of digitalisation. Then, construct a multi-objective cost optimisation model for engineering enterprises. Second, the Multi-Objective Particle Swarm Optimisation (MOPSO) algorithm is introduced to solve multi- objective problems. To improve the multi-objective optimisation effect of the model, the inertia weight parameters and particle learning behaviour are optimised and adjusted, as the model is prone to getting stuck in local optima. In the performance test of the algorithm model, the optimised MOPSO model can accurately search for the minimum value of 0 at the position (0, 0) under the Rastrig in function, and at the same time, the number of iteration convergence is the least. The GA, ACOM, and traditional MOPSO models have more iterative convergence times, and the optimisation results are 0.10, 0.15, and 0.14, respectively. It can be seen that the performance of the optimised MOPSO model is better. In the specific example analysis, using the optimised MOPSO solution, the project cost was reduced from 31 million yuan in the contract to 30.52 million yuan, and the construction period was shortened from 588 days to 540 days, and met the environmental protection and quality requirements. The research content can provide important decision support for engineering project managers.