Comprehensive Utilization Of Resources Research Articles

Dissolution Behaviors of Recycled Cement Paste and Lime in EAF Slag Under Static Conditions

AbstractRecycled cement paste (RCP) is a CaO-rich resource that is recycled from waste concrete and waste cement. For reducing environmental impact and promoting comprehensive resource utilization, RCP could partially replace lime as flux in electric arc furnace (EAF) steelmaking process. In this study, the dissolution behaviors of RCP and lime in EAF slag at 1400 °C and 1500 °C were investigated using static dissolution experiments. The measured dissolution rate constant of lime at 1400 °C and 1500 °C is 3.12×10−5 and 8.42×10−5 m/s, respectively, while that for RCP is 1.37×10−4 and 2.91×10−4 m/s, respectively. For the lime dissolution, a dense dicalcium silicate (C2S) product layer was generated at the dissolution interface, with the diffusion of Ca2+ in the C2S layer being the limiting step for the lime dissolution. However, for the RCP dissolution, no product layer was observed at the dissolution interface. Instead, a dissolution intermediate layer forms due to slag penetration. During the dissolution of RCP, Ca2+ and SiO44− diffuse from RCP layer to slag, while Fe2+ and AlO45− diffuse from slag to RCP layer accumulating in the dissolution intermediate layer. Furthermore, a dissolution model was developed based on current experimental results, which helps to predict dynamic dissolution process of lime and RCP in EAF slag. In general, the dissolution rate of RCP in EAF slag was much higher than that of lime, partially adding RCP as flux in EAF could accelerate the liquid slag formation in EAF steelmaking process.

Problems and prospects of rural energy transformation in China

In recent years, Chinas rural energy supply security capacity has been enhanced, and the adjustment of energy structure has achieved remarkable results, but there are still some problems: The low utilization rate of waste energy in rural areas restricts the comprehensive utilization of resources and environmental protection, the level of rural energy consumption is always in the stage of development, and the lagging construction of rural energy socialized service system restricts the development of rural energy. In view of the problems and challenges faced by Chinas rural energy development, focus on rural energy consumption. This paper analyzes the basic situation of energy development in Chinas rural areas (taking Lantian County of Shaanxi Province as an example). Under the special premise of Chinas national conditions, the specific characteristics of different development in different regions are integrated, and the traditional fossil energy is gradually replaced by the storage and utilization of rural waste and new energy. The key issues such as the construction of rural energy service system and policy guidance are studied, and the measures and suggestions for promoting the scientific development of rural energy in China are put forward.

Selective depression of biodegradable talc depressant sodium carboxymethyl starch on molybdenite flotation with sodium diethyldithiocarbamate

The selective separation of molybdenite and talc is still a challenging problem owing to its excellent inherent hydrophobicity. In this study, sodium carboxymethyl starch was evaluated for the first time as a cost-effective talc depressant to achieve the molybdenite-talc separation with sodium diethyldithiocarbamate, a collector widely used to float sulfide minerals. The single-mineral and multi-mineral flotation tests witness carboxymethyl starch has shown a selective depression on talc and has little effect on molybdenite recovery with sodium diethyldithiocarbamate as a collector, terpineol as a frother and pH = 8 ± 0.5 (at an industrially relevant pH). Furthermore, experimental comparison of FTIR, equilibrium adsorption and XPS analysis demonstrate that the adsorption of sodium carboxymethyl starch on the talc surface can be considered to be irreversible under these conditions, and the higher adsorption density of sodium diethyldithiocarbamate on molybdenite over talc has highlighted the importance of differential adsorption density in the predictions of the efficient separation of molybdenite and talc. The innovative method may be applied efficiently in industrial applications to improve the comprehensive utilization of resources.

Maximizing resource recovery: A green and economic strategy for lithium extraction from spent ternary batteries

Spent ternary lithium-ion batteries contain abundant lithium resource, and their proper disposal is conducive to environmental protection and the comprehensive utilization of resources. Separating valuable metals in the ternary leaching solution is the key to ensuring resource recovery. However, the traditional post-lithium extraction strategies, which heavily rely on ion exchange to remove transition metal ions in the leachate, encounter challenges in achieving satisfactory lithium yields and purities. Based on this, this paper proposed a new strategy to prioritize lithium extraction from ternary leachate using “(+) LiFePO4/FePO4 (-)” lithium extraction system. The preferential recovery of lithium can be realized by controlling the potential over 0.1 V versus Standard Hydrogen Electrode (SHE) without introducing any impurity ions. The lithium recovery rate reaches 98.91%, while the rejection rate of transition ions exceeds 99%, and the separation coefficients of lithium to transition metal ions can reach 126. Notably, the resulting lithium-rich liquid can directly prepare lithium carbonate with a purity of 99.36%. It provides a green and efficient strategy for the preferential recovery of lithium from the spent ternary leachate.

Research on resource comprehensive utilization of granite-type sulfide mine tailings

In order to recover and utilize mica and quartz from the tailings of a granite-type sulfide ore in Jiangxi Province, the technique of separating mica and quartz from the tailings by flotation without acid was investigated. Pyrite flotation was performed on a 500 g tailing sample to remove pyrite. And the middlings were acquired by desliming of the unfloated products. Finally mica and quartz was separated from the middlings in the mechanical flotation cell. Under conditions of pH=10.3 with a pulp concentration of 35% and a collector concentration of 180 g/t, a yield of 12.89% mica and 42.73% quartz was obtained, with silica grades as high as 71.50% in the quartz. The mica and quartz products can be used in construction ceramics and construction sand, respectively. It is believed that the outcomes of this work could provide ideas for comprehensive utilization of sulfide tailings.

Synergetic evolution mechanism of coastal resources utilization and coastline change of muddy coast in Jiangsu

Coastal areas possess unique geographical advantages and abundant resources, making them economic development hubs for coastal cities worldwide. However, the overexploitation of coastal resources significantly impedes the sustainable development of these areas. To address this issue, it is crucial to gain a comprehensive understanding of resource utilization patterns over time. Previous studies on resource utilization in the coastal areas of Jiangsu, China, have primarily relied on historical narratives with limited quantitative assessments. In this study, we utilize the Resource Utilization Comprehensive Index (RUCI) to evaluate the status of resource utilization in Jiangsu's coastal areas for the last 1300 years. Based on the characteristics of coastline changes from the Tang Dynasty to 1929 analyzed through the Digital Shoreline Analysis System (DSAS) in ArcGIS, we use entropy weight method (EWM), gray relation analysis (GRA) and Pearson correlation coefficient to determine the RUCI of coastal areas in Jiangsu and analyze its correlation with each evaluation index and influencing factor. The results show that (1) over the past 1300 years, the coastline of Jiangsu primarily underwent a sedimentation process characterized by three stages: slow sedimentation, rapid sedimentation, and north erosion followed by south sedimentation, (2) the comprehensive utilization of resources along the Jiangsu coast was gradually developed from the Tang Dynasty to the Republic of China, with the best utilization achieved during the Qing Dynasty, and (3) the changes in the coastline exhibited a substantial influence on the comprehensive utilization of resources and there was a high correlation between the two. Based on these findings, we propose several policy development suggestions. This study provides a scientific basis for understanding the synergetic evolution mechanism of coastal resources utilization and coastline change in Jiangsu under global change.

Evaluation of optimal waste lithium-ion battery recycling technology driven by multiple factors

As energy and environmental issues become increasingly prominent, the process of global carbon emission reduction is now underway. In the transportation sector, the application of electric vehicles is an effective way to achieve energy saving and emission reduction. Lithium-ion battery, an important component of electric vehicles, has received widespread attention for its advantages including small size, high energy density and smooth discharge voltage. However, their potential safety and pollution issues are becoming prominent and must be properly handled. Moreover, the technical route and future direction of LIB recycling are still unclear at this stage. Herein, this paper evaluates different waste lithium-ion battery recycling technologies in a multi-criteria decision framework to determine the best technology. A criteria system driven by multiple factors is established, including environmental impact (C1), technical risk (C2), comprehensive resource utilization (C3), resource consumption (C4) and economic performance (C5). Subsequently, since the optimal technology is novel and difficult to select, the hesitant fuzzy linguistic term sets are used to express the degree of hesitation in expert decision making. Finally, from the aspects of the choice of sorting method, the Tomada de decisao interativa multicriterio method based on the expectation effect is used to evaluate the optimal waste lithium-ion battery recycling technology, and the validity of the framework is illustrated by data analysis.

Comprehensive evaluation of green mine construction level considering fuzzy factors using intuitionistic fuzzy TOPSIS with kernel distance.

With increasing concerns about climate change and resource-environmental limitations, the green development of the mining industry has become mainstream and gained much support. Driven by the concept of sustainable and green development, China has made the advancement of green mine construction a crucial part of establishing an eco-society and has put forward the overall goal of green mines. An important future strategy is to evaluate a large number of mines. However, developing scientific, reliable, and comprehensive index systems and evaluation methods is extremely difficult because of the objective complexity of green mine evaluation and the fuzziness of some indicators. The kernel method and intuitionistic fuzzy set can effectively handle these problems. This study proposed a comprehensive evaluation index system and a hybrid evaluation method based on the kernel distance measure and intuitionistic fuzzy TOPSIS method. The index system contains 22 indicators considering six aspects: mining area environment, resource development mode, comprehensive utilization of resources, energy saving and emission reduction, technical innovation, and corporation management. The hybrid evaluation method was applied to the practical assessment of ten green mines in Panxi, China. Comparative analyses were carried out to demonstrate its applicability and sensitivity. The results verify that the hybrid method can fully depict the construction achievements of green mines in all aspects with strong reliability and stability. This approach is a valuable reference for evaluators and decision-makers in government departments.

Full quantitative resource utilization of raw mustard waste through integrating a comprehensive approach for producing hydrogen and soil amendments

BackgroundPickled mustard, the largest cultivated vegetable in China, generates substantial waste annually, leading to significant environmental pollution due to challenges in timely disposal, leading to decomposition and sewage issues. Consequently, the imperative to address this concern centers on the reduction and comprehensive resource utilization of raw mustard waste (RMW). To achieve complete and quantitative resource utilization of RMW, this study employs novel technology integration for optimizing its higher-value applications.ResultsInitially, subcritical hydrothermal technology was applied for rapid decomposition, with subsequent ammonia nitrogen removal via zeolite. Thereafter, photosynthetic bacteria, Rhodopseudomonas palustris, were employed to maximize hydrogen and methane gas production using various fermentation enhancement agents. Subsequent solid-liquid separation yielded liquid fertilizer from the fermented liquid and soil amendment from solid fermentation remnants. Results indicate that the highest glucose yield (29.6 ± 0.14) was achieved at 165–173℃, with a total sugar content of 50.2 g/L and 64% glucose proportion. Optimal ammonia nitrogen removal occurred with 8 g/L zeolite and strain stable growth at 32℃, with the highest OD600 reaching 2.7. Several fermentation promoters, including FeSO4, Neutral red, Na2S, flavin mononucleotide, Nickel titanate, Nickel oxide, and Mixture C, were evaluated for hydrogen production. Notably, Mixture C resulted in the maximum hydrogen production (756 mL), a production rate of 14 mL/h, and a 5-day stable hydrogen production period. Composting experiments enhanced humic acid content and organic matter (OM) by 17% and 15%, respectively.ConclusionsThis innovative technology not only expedites RMW treatment and hydrogen yield but also substantially enriches soil fertility. Consequently, it offers a novel approach for low-carbon, zero-pollution RMW management. The study’s double outcomes extend to large-scale RMW treatment based on the aim of full quantitative resource utilization of RMW. Our method provides a valuable reference for waste management in similar perishable vegetable plantations.

Construction Practices of Green Mines in China

To maintain high-level economic development, protect the ecological environment, and achieve carbon peaking and carbon neutrality goals, the construction of green mines has become a critical issue in China. In this study, the importance of mineral resources to human society is discussed, and the construction experiences and sustainable development directions of green mines are summarized, which can provide valuable references for the global mining industry. The entry and management process in China was introduced to help understand green mines’ construction objectives and tasks. Moreover, based on the successful construction cases of green mines, four typical green mine models are concluded: the green technology mining model, operation modernization mining model, stability mining model, and ecological restoration mining model. In addition, the key construction elements of green mines are concluded, for example, the mining environment, mining methods, comprehensive utilization of resources, energy conservation, emission reduction, scientific and technological innovation and intelligence, and enterprise-land stability, which provided the directions and guidance for green mine construction.

Resource-Based Utilization of Mineral Mining Operations in Panzhihua City, China: Basis for Strategic Plan

The comprehensive utilization of resources has become an urgent task to transform the mode of economic growth, develop a circular economy, build a resource-saving and environment-friendly society. The study conducted descriptive analysis to examine the resource-based utilization of mineral mining operations in Panzhihua City, China, through interviews with management and employees using questionnaires. It systematically described various aspects of mining operations, such as resource annual production, electric power consumption, manpower utilization, facilities and equipment, logistics, and production costs. Challenges highlighted included the gradual process of obtaining buy-in from managers and employees and convincing consumers to prioritize environmental protection. Based on these findings, a strategic plan was developed for mineral mining operators in Panzhihua City, focusing on addressing weaknesses and implementing strategies to improve resource utilization in areas like production, power consumption, manpower utilization, facilities, equipment, logistics, and production costs. These insights and strategies are crucial for mining operators in Panzhihua City to navigate challenges effectively and improve overall performance in resource utilization and allocation, ensuring long-term success and sustainability in the competitive mining industry landscape.

Profile, Status, and Prospects of Electronic Companies in Foshan City: Basis for Development Plan

The comprehensive utilization of resources has become an urgent task to transform the mode of economic growth, develop a circular economy, build a resource-saving and environment-friendly society, and an important way to ensure the sustainable use of resources, reduce the pressure of environmental pollution, improve the efficiency of resource utilization and improve the quality of economic development. The study utilized a descriptive research method, the study aims to depict the profile, status, and prospects of these companies, with a particular focus on marketing, technical, and financial aspects for strategies, and innovation, opportunities, and challenges for operations. The respondents involved in the research are the managers or business owners of these electronic companies. Significant findings reveal that the five electronic companies in Foshan City are substantial in size, operating as joint-stock companies with assets valued in millions of RMB and employing thousands of individuals, primarily focused on household appliances. Strategies within these companies, particularly in marketing, technical, and financial areas, require enhancement to meet the continuously evolving needs and demands of the market, influenced by changes in technology and consumer behavior. Operations within electronic companies, emphasizing innovation, opportunities, and challenges, are crucial variables to consider for improving competitiveness in the electronic products industry. The study's output presents a proposed development plan deemed helpful for the electronic companies in Foshan City, providing a roadmap for their future growth and success.

Evaluation of green mine construction level in Tibet based on entropy method and TOPSIS

Green mine construction is a systematic project involving the whole life cycle of mineral resources exploitation and utilization, representing the overall level of development potential. As an important strategic mineral resources reserve base in China, Tibet is rich in mineral resources. In order to calculate the level of green mine construction in Tibet, we obtained different data sources such as statistical yearbooks and mine construction information through field research and discussion. We establish the EMUCIMH evaluation system, select a total of 20 indexes from seven aspects(ecological mining environment, scientific mining method, efficient resource utilization, standardization of energy conservation and emission reduction, intelligent mine construction, standardization of enterprise management and harmonization of mining community),using the Entropy Weight TOPSIS Method to study the problems existing in the process of green mine construction, expecting to provide some references for government departments to make management decisions and for mining enterprises to improve green mine construction. The results show that among the 11 national green mines in Tibet, the construction status is uneven, and there are large differences in the mining methods, the comprehensive utilization of resources, and the ecological environment of mining areas. In contrast, The difference of standardization of enterprise management, intelligent mine construction and the harmonization of mining community is small. Among the specific indicators, in terms of exhaust emissions, mining community harmony and corporate culture are doing well, while they are relatively poor in terms of environmental management and monitoring, technological innovation, and intelligent mine, which need to be improved. Large and medium-sized mines, especially metal mines, the overall level of green mine construction is high, followed by small and medium-sized metal mines and individual Non-metal large mines, and mines with more historical problems faced more difficulties and challenges.

Discussion on Comprehensive Utilization and Ecological Management of Coal Gangue

Coal production will continue to increase year by year, and the amount of waste discharged will also increase year by year. In addition, the amount of coal waste accumulated in the past is quite huge. In order to implement the concept of ecological civilization in the new era, reduce the atmospheric, water, and ecological environmental problems caused by the accumulation of coal gangue in the region, solve the safety and environmental risks of existing waste disposal sites, restore the ecological and environmental functions of waste disposal sites and surrounding areas, and improve the comprehensive utilization rate of coal gangue, in accordance with relevant policies such as environmental protection and resource comprehensive utilization, and the requirements for the construction of a "waste free city" in Shenmu City, Combining the actual needs of creating a "waste free enterprise". Therefore, the comprehensive utilization and ecological management of coal gangue has become an urgent and urgent social issue that needs to be studied and solved.

Valuable Recovery Technology and Resource Utilization of Chromium-Containing Metallurgical Dust and Slag: A Review

As a type of metallurgical solid waste with a significant output, chromium-containing metallurgical dust and slag are gaining increasing attention. They mainly include stainless steel dust, stainless steel slag, ferrochrome dust, and ferrochrome slag, which contain significant amounts of valuable elements, such as chromium, iron, and zinc, as well as large amounts of toxic substances, such as hexavalent chromium. Achieving the harmless and resourceful comprehensive utilization of chromium-containing metallurgical dust and slag is of great significance to ensuring environmental safety and the sustainable development of resources. This paper outlines the physicochemical properties of stainless steel dust, stainless steel slag, ferrochrome dust, and ferrochrome slag. The current treatment technologies of chromium-containing metallurgical dust and slag by hydrometallurgy, the pyrometallurgical process, and the stabilization/solidification process are introduced. Moreover, the comprehensive utilization of resources of chromium-containing metallurgical dust and slag in the preparation processes of construction materials, glass ceramics, and refractories is elaborated. The aim of this paper is to provide guidance for exploring effective technology to solve the problem of chromium-containing metallurgical dust and slag.

Water Fertilizer Integration Equipment Research Status and Development Trend

Integrated water and fertilizer technology can accurately adjust the mix of water and fertilizer on demand, and then through the irrigation system, water and fertilizer are delivered to the roots of the crop in quantity, on time, and with precision. As an important part of the integrated system of water and fertilizer, the fertilizer has a critical influence on the quality of the fertilizing system. Nowadays, the development of intelligent agriculture has become a general trend of agricultural development. By exploring the development process of water and fertilizer mixing, this paper sorted out the research status of various kinds of fertilizers in China, compared different mixing methods of water and fertilizer, and analyzed and summarized the excellent working performance of different fertilizers. Secondly, the current research emphases were discussed, including precision fertilization technology, intelligent control, comprehensive utilization of resources and circular agriculture. Then, the development trend of integrated water and fertilizer equipment is put forward, including the improvement of precision fertilization, the development of multifunctional integrated equipment, and the application of data management and decision support system. Through continuous technological innovation and application, the integrated equipment of water and fertilizer is expected to play a greater role in the agricultural field.

Radon exhalation characteristics after pyrolysis of long flame coal

Coal pyrolysis is a important method for classifying and utilizing coal resources and contributes to enhanced comprehensive resource utilization. However, In high-temperature areas such as coal pyrolysis, there is an abnormal phenomenon release of radioactive gas radon, understanding the relationship between temperature and radon exhalation characteristics, as well as the underlying mechanisms, holds great importance for assessing radon pollution in mining areas. After coal undergoes pyrolysis under high temperature conditions, its material composition, pore structure, water content, and other properties have changed. The pyrolysis products in different atmosphere environments have differences, and the characteristics of radon emission are also different. To address this, the present study conducted coal pyrolysis experiments in both aerobic and anaerobic environments, using long flame coal sourced from Yulin, China. The radon release concentration of the pyrolysis products was measured. The research findings indicate that during pyrolysis at elevated temperatures, the ratio of coal mass loss is constantly increasing. High temperatures promote the development of pores and fissures, and significant changes in coal properties at temperature thresholds (300 °C and 500 °C). The specific surface area, pore volume, and fracture ratio all display substantial increases, and the amplitude of change is greater under aerobic conditions. The fractal dimension of total pores and macropores shows continuous growth, while the specific surface area, pore volume, and fracture ratio exhibit a strong negative correlation with the radon emission rate of pyrolysis products. The expansion and penetration of pores and cracks, along with the release of a substantial amount of pyrolysis gas, accelerate the transformation, migration, and exhalation of radon, resulting in a negative correlation between the heat treatment temperature and the radon release rate of pyrolysis products. Under aerobic conditions, the radon release rate of pyrolysis products decreases more significantly.

Synthesis of tung oil-based polyphenols via phosphotungstic acid loaded tung meal-based carbon-catalyzed Friedel-Crafts alkylation: A smart way to access renewable bio-based polyurethanes

Achieving green preparation and economical recycling of polyurethane (PU) foams while considering environmental protection and comprehensive resource utilization is a significant challenge. Herein, we have proposed an integrated utilization strategy of tung oil fruit to design tung oil-based PU (TPU) foams with malleability and thermal processability. Phosphotungstic acid was first loaded onto tung meal-based carbon derived from the solid microwave carbonization of waste tung meal to obtain carbon-based catalysts with a total acid density of up to 2408.4 μmol/g. In the Friedel-Crafts alkylation reaction of tung oil and guaiacol, the carbon-based catalysts show highly catalytic performance and reusability, resulting in the phenolic hydroxyl content of tung oil-based polyphenols reaching 3.05 mmol/g. The TPU foams containing phenol-carbamate bonds were prepared from tung oil-based polyphenols, which can be processed into TPU films through thermal compression molding. The recycled TPU films show tunable mechanical properties and can be further reprocessed. We have also produced carbon fiber-reinforced composites with TPU as the matrix, which have good mechanical properties and can be sustainably recycled. This research aims to produce closed-loop recycling-oriented TPU foams using forest resources as raw materials while adequately using waste to achieve green production processes.

A novel combined metallurgy-beneficiation method for the facile and low-cost comprehensive resource utilization of low-grade kaolin solid wastes

Low-grade kaolin is the largest emissions of industrial solid waste that is difficult to dispose of and pollutes the environment seriously. From the perspective of harmless and complete resource utilization, we proposed a novel strategy that combines the wet leaching under mild conditions and physical beneficiation for the facile and low-cost high-valued utilization of low-grade kaolin that involves high-efficiency recovery of aluminum (Al), silicon (Si), and titanium (Ti). The key to successful implementation of this method lies in the new discovery that the residual SiO2 after Al extraction of kaolinite by acid leaching under specific conditions could be rapidly dissolved in dilute NaOH solution at room temperature 25 °C. This highly reactive SiO2 challenges the conventional notions of various silica species are usually chemically stable. By adjusting the key technical parameters of the thermal activation-acid leaching process, the selective and efficient extraction of Al2O3 from low-grade kaolin was realized. The acid leaching residue was then subjected to selective recovery of SiO2 by alkaline leaching at 25 °C to obtain high-quality sodium silicate. Finally, the alkali leaching residue as titanium coarse concentrate was separated by centrifugal concentrator to obtain artificial rutile (TiO2 >91.06%). The key mechanism for the formation of the highly reactive silica was also systematically studied and confirmed.

An Integrated Approach to Green Mines Based on Hesitant Fuzzy TOPSIS: Green Degree Analysis and Policy Implications

China proposes to construct green mines as one of the significant means to elevate the green degree of mining industry and protect the mining environment. This paper constructs six evaluation indicators, namely mine environment, Resource development mode, Comprehensive utilization of resources, Energy conservation and emission reduction, Technological innovation and digital mining, Enterprise management and corporate image, to reflect green degree of mining firms. An improved multiattribute evaluation method (MAEM) is proposed based on hesitant fuzzy TOPSIS and kernel method. A case study of green mining firms in Panxi, southwestern China is provided to demonstrate the application of the proposed model. According to the research in this paper, it is more appropriate to expand the data in accordance with the optimistic criteria. The results also show that the improved hesitant fuzzy TOPSIS is a better method in the evaluation of green degree. Through the results of this paper, a reasonable and scientific method is introduced for the evaluation of the green degree of mining firms, and it can be promoted to the evaluation of the mineral resource development efficiency.