Industrial By-products Research Articles

Carbon-capture potential of industrial by-products for post-carbon society

To contribute to the realization of carbon neutrality by 2050, the authors have focused on the fact that some of the by-products of social activities have the ability to fix carbon dioxide, and have envisioned the creation of a carbon-capture urban environment using these materials. Also, the authors have emphasized carbon capture capabilities of industrial waste disposal facilities named as “Disposal Facility CCS”, since these are where substances containing large amounts of free calcium accumulate. As described herein, the authors have emphasized several kinds of by-product as carbon capture materials, and propose datasets of these carbon capture capabilities by measurement using constant flow aeration type CO2 fixation testing, which we developed. Furthermore, using these datasets, the authors estimate the potential carbon capture capability of a specific industrial waste disposal facility as an example of “Disposal Facility CCS”, and demonstrate its relative effectiveness compared to that of forests. Furthermore, the authors estimate the carbon capture potentials of industrial by-products generated in Japan as some examples. Consequently, this study proposed carbon capture future society concept using CO2 fixation materials on the basis of the estimation results conducted in this study.

Sustainable Stabilization of Brown and Green Clays Using Industrial By-products

Background The disposal of industrial by-products and the rising cost of construction materials are critical issues globally, particularly in developing nations such as Jordan. Brown and green clay are considered problematic types of soft clay, as they fail to meet the necessary specifications for use in construction. Objective This study aims to assess the efficiency of Cement Kiln Dust (CKD) and Silica Fume (S.F.) as stabilizing agents for brown and green clays. The research explores how CKD and S.F. can be used as cost-efficient and eco-friendly alternatives to enhance the mechanical properties of soft clays, improving their viability for construction. Methods An experimental approach was used to investigate the impact of CKD and S.F. on brown and green clay stabilization. The study examines the effect of varying CKD and S.F. concentrations on the clays' plasticity, compaction, unconfined compressive strength, and consolidation properties. CKD was tested at four different levels (0%, 5%, 10%, and 15%), as was S.F. (0%, 5%, 10%, and 15%). Results The findings revealed a notable enhancement in the engineering properties and behavior of both brown and green clay, with reductions observed in the plasticity index (P.I.), compression index (Cc), compressive strength (qc), and maximum dry density (γd). Conclusion Adding 15% CKD to brown clay resulted in the most significant improvements after a curing period of 7 days based on the unconfined compressive strength test results.

A Closed-Loop Economy in the Meat Industry for Generating Alternative Energy from Biogas Plants

This study deals with the concept of a closed-loop economy in the meat industry through the use of animal by-products in biogas plants for electricity generation processes. The purpose of the study was to identify the volume of by-products from the slaughter of cattle and pigs, how the by-products are managed, and the efficiency of their use in biogas plants for electricity production processes. The analyses used data from the Central Statistical Office, the Chief Veterinary Inspectorate, and information obtained from the Polish Agency for Enterprise Development. Studies from the literature on closed-loop economies and bioeconomies were also a valuable source of information. Based on case studies, this paper also presents examples of a closed-loop economy in meat companies. In the area of pork, poultry, and beef livestock production, the analysis covered the years 2004–2022, while in the area of the production and use of meat industry by-products, the data came from 2017–2022. The study shows that reducing the production of waste in the meat industry and the reuse and recycling of waste are important parts of a closed-loop economy. In meat companies, waste from slaughtering animals can be properly managed, either by processing it into animal feed or by using it in biogas plants to generate electricity or heat. Taking into account the number of by-products from cattle and pig slaughter in the country, biogas plants could produce approximately 95,232 MW of electricity per year, which constitutes approximately 4.3% of the energy intensity of the meat industry in Poland.

Research Possibilities for Efficient Capitalization in Construction Eco-Products, of Mineral Additions Generated by the Local Romanian Industries as Wastes or By-Products

The current paper intends to present the directory lines and paths for the development and implementing construction eco-products, with advanced functionality (materials, elements and structures, models and technologies), considering the efficient and customized valorization of by-products and generated waste of local industries, in the context of National Strategy for Research, Innovation and Smart Specialization 2022-2027 regarding the transition to Circular Economy (EC). This represents one of the two main axes of the research project Nucleu Programme of the National Research Development and Innovation Plan 2022-2027, supported by MCID, "ECODIGICONS" project no. PN 23 35 04 01: “Fundamental-applied research into the sustainable development of construction products (materials, elements, and structures, as well as methods and technologies) that utilizes current national resources to enhance the eco-innovative and durable aspects of Romania's civil and transport infrastructure”, financed by the Romanian Government starting with the beginning of 2023. One of the novelties of the proposed approach of the project is considering the entrepreneurial environment of construction industry or complementary branches as essential stakeholders for the future results of the current scientific research. This dramatically changes the dynamic of the project, in terms of specific objectives, namely their focus on solving the current wastes’ problem by innovatively integrating them into competitive construction products with fast applicability and in accordance with support market requests. By the use of strategic management specific methods (e.g., External Environment (EE) and Internal Environment (IE) evaluation, SWOT analysis and derived specific strategies, etc.), four research directions have been identified for the valorization, at regional or even national level, of mineral additions (inert/hydraulically latent/pozzolanic, etc., derived from waste and industrial by-products (metallurgy, processing industry, construction/demolition, etc.)) by development of eco-smart materials and products for construction. The three directions are related to the considered mineral additions: Power plant ashes (fly ash and/or bottom ash), Steel slag and Garnet type residue Hence, the paper is willing to present the identification and the preliminary analyses of the specified research axes, plotted as necessary steps for achieving an intelligent and sustainable transition of the Romanian construction infrastructure. This approach implicitly ensures in the short and medium term, the increase of the degree of implementation of the principles of the Circular Economy (EC) in Romania, in the existing context which includes relevant factors like: geo-political, industrial and economic, urban and demographic, scientific, socio-cultural and environmental, in accordance with the imperatives of National, European and World Sustainable Development strategies.

A novel approach of using SiC for the reductive decomposition of industrial by‐product gypsum

AbstractIn this study, thermodynamic calculations indicate that using silicon carbide (SiC) as an additive for the reductive decomposition of industrial by‐product (IBP) gypsum is a feasible method to lower decomposition temperature and avoid the generation of liquid phase. Experimental results show that the decomposition rate of IBP gypsum exceeded 90% at 950°C for 2 h, while avoiding the generation of liquid phase. In addition, it was found that an intermediate product, 2Ca2SiO4·CaSO4, was generated during the decomposition process. Through the reaction mechanism and kinetics analysis of IBP gypsum and SiC, the decomposition process can be divided into two steps. The first step was the conversion of CaSO4 to 2Ca2SiO4·CaSO4 (decomposition rate <60%), and the chemical reaction was the controlling step. The second stage was the conversion of 2Ca2SiO4·CaSO4 to Ca2SiO4 (decomposition rate >60%), and three‐dimensional diffusion was the controlling step. This novel method not only successfully lowered the decomposition temperature of IBP gypsum, but also avoided liquid phase generation.

Research Progress on Leaching of Rare Earth Elements in Phosphogypsum

With the increasing global demand for rare earth elements and the depletion of traditional mineral resources, recycling rare earth elements from industrial solid waste has become an important direction of sustainable resource utilization. Phosphogypsum is a kind of industrial by-product with huge output and trace rare earth elements, its effective treatment and resource utilization are of great significance for environmental protection and economic development. Based on the occurrence state of rare earth elements in phosphogypsum, the research progress of leaching of rare earth elements in phosphogypsum was reviewed in this paper. The leaching mechanism and influencing factors of different leaching agents were summarized and analyzed.

Investigation Report on Characteristics Strength Partial Replacement of Fine Aggregate with Copper Slag and Granite Powder

Concrete is one of the most widely used construction materials, consisting of cement, fine aggregates, coarse aggregates, and water. Traditionally, Ordinary Portland Cement (OPC), river sand, and Hard Broken Granite (HBG) stone are used in concrete production. However, the over-extraction of these natural resources has led to environmental concerns and increased costs. This has created a need for sustainable alternatives that maintain concrete’s quality and performance. This study investigates the partial replacement of fine aggregates with copper slag and granite powder in M25 grade concrete. Copper slag, a by-product of copper smelting, and granite powder, obtained during granite stone cutting, possess physical and chemical properties that make them suitable for concrete. Additionally, Pozzolana Portland Cement (PPC) is examined as a sustainable alternative to OPC. PPC, with its pozzolanic characteristics, enhances workability, chemical resistance, and long- term strength while reducing the carbon footprint. The research evaluates the mechanical and chemical properties of concrete incorporating PPC, copper slag, and granite powder. The study also highlights the environmental and economic benefits, demonstrating how these materials can contribute to sustainable construction practices. By promoting the use of industrial by-products and alternative binders, this research aims to develop high-performance, eco-friendly concrete suitable for modern construction needs. Keywords: Concrete, sustainable construction, fine aggregate replacement, copper slag, granite powder, Pozzolana Portland Cement (PPC), M25 grade concrete, industrial by-products, environmental sustainability.

UTILIZATION OF ALUMINA AND STEEL INDUSTRIAL WASTE FOR THE DEVELOPMENT OF CONTROLLED LOW STRENGTH MATERIALS

The study aimed at incorporating Red Mud, a byproduct of bauxite ore extraction, and Ground Granulated Blast Furnace Slag (GGBS), a byproduct of the steel industry, into Controlled Low Strength Materials (CLSM). These materials were combined with M Sand and cement to develop a sustainable and cost-effective construction material. Utilizing Red Mud and GGBS addresses waste disposal challenges while enhancing CLSM properties, making it a more environmentally friendly option. By converting industrial byproducts into valuable construction components, the research contributes to sustainable development and the circular economy. The research methodology involves creating five different dry mix combinations, varying the proportions of Red Mud, GGBS, M Sand, and cement. Each combination was tested with four different water contents to evaluate their engineering and dynamic properties. This methodical approach was focused to identify the optimal mix that balances strength and workability. By analyzing these properties, the study provided a valuable insight into the behavior of CLSM under various conditions, contributing to the advancement of more efficient construction materials. The systematic testing ensured that the developed CLSM mixes met the necessary performance criteria for practical applications. The primary objective of the study was to develop a phenomenological model based on the obtained strength and flow values. This model will serve as a predictive tool for future research, aiding in the design of CLSM mixtures with desired characteristics. By demonstrating the feasibility of using Red Mud in CLSM, the research underscores its potential to offer cost-effective and sustainable solutions for various engineering applications. This innovative approach not only promotes waste utilization but also opens new possibilities for improving construction practices. The developed model will help engineers and researchers predict the performance of new CLSM formulations, streamlining the development process for future projects.

Evolution characteristics of microwave absorbing carbon material on surface of CoFe2O4@biochar during hydrogen production from methane decomposition process

This study proposes a strategy to convert carbon deposits, generated during the catalytic decomposition of methane for hydrogen production, into high-performance microwave-absorbing materials. This approach not only reduces carbon emissions but also achieves carbon fixation and reuse, promoting environmental sustainability. The research demonstrates that cobalt ferrite (CoFe2O4)-loaded biochar catalysts, at different proportions, exhibit highly efficient and selective hydrogen production capabilities in the process of methane decomposition and hydrogen production, with a peak methane conversion rate as high as 83.6 %, which is higher than that of pure biochar catalysts. The improvement was significant, with an increase of 2.2 times. This catalyst not only strengthens the stability of methane decomposition, but also effectively shortens the reaction induction period, showing excellent catalytic performance and stability. Following methane cracking, an ordered, highly crystalline graphitic carbon structure forms within the catalyst, significantly improving its microwave absorption capacity. At a thickness of 1.3 mm, the catalyst’s microwave absorption reaches a peak value of −41.39 dB, with an effective absorption bandwidth of 4.56 GHz. The catalyst’s outstanding microwave absorption performance arises from synergistic mechanisms, such as multi-layer reflection and interface polarization, which effectively convert electromagnetic energy into thermal energy, facilitating efficient electromagnetic wave dissipation. This research presents an efficient catalyst for the clean utilization of methane resources and explores new pathways to convert industrial by-products into high-value materials, particularly with potential applications in microwave-absorbing technologies.

Transforming fly ash into value: Sustainable LLDPE-fly ash composites via rotational molding

This study focuses on reducing pollution and promoting sustainability by exploring the use of fly ash (FA), an industrial byproduct, in polymer composites through rotational molding. By incorporating FA into a polymer matrix, the research evaluates the performance of these composites. Results show that the tensile strength increased slightly from 16.54 MPa for pure LLDPE to 17.2 MPa with 5% FA but decreased to 13.5 MPa at 10% FA. The modulus significantly improved, rising from 5.1% to 31.3% with 5% to 20% FA content. Hardness also increased, with a maximum rise of 10.25% at 5% FA and 6.2% at 10% FA. However, elongation at break, bending, and impact strength decreased with higher FA content. The density of the composites increased with up to 10% FA, indicating effective integration of FA particles. These findings demonstrate that FA can be successfully used to develop polymer composites in rotational molding, supporting both environmental sustainability and innovative production practices.

Integrated production of bioethanol and biomethane from rice waste using superior amylolytic recombinant yeast.

This study utilized a circular economy approach to convert unripe rice, a low-cost by-product of the rice milling industry, into biofuels using a biorefinery process. The recombinant yeast Saccharomyces cerevisiae ER T12.7 strain was tested for its ability to produce ethanol from unripe rice. In hydrolysis trials with 20 % (dw/v) UR, ER T12.7 showed superior saccharification yields comparable to the commercial enzyme STARGENTM 002. In 1-L bioreactor tests, ER T12.7 produced ethanol as efficiently as the parental ER V1 strain under simultaneous saccharification and fermentation. The spent fermentation broth from both amylolytic strains was evaluated for biomethane production, achieving high yields of up to 373.61 mL CH4/g volatile solids. This research is the first to demonstrate process integration to produce ethanol and methane from rice waste sequentially, highlighting the potential of unripe rice in biorefining for a circular economy.

Upcycling heavy impure crude terephthalic acid into porous carbons for adsorption of dye pollutants: The role of endogenous ferric groups

Crude terephthalic acid (CTA), a byproduct in the textile industry, is generated from the acid-precipitation process during the treatment of alkali-peeling (AP) wastewater. Due to its heavy impurity, CTA is typically disposed of as solid waste through incineration and landfilling, leading to severe pollution and resource wastage. In this work, an upcycling method was explored to convert CTA into carbonaceous adsorbent through pyrolysis at temperatures ranging from 400 to 800 °C. The carbonization mechanism of CTA to carbon was thoroughly investigated by using TGA-MS, FT-IR and XPS analyses. The resulting CTA carbons exhibited excellent adsorption performance for dye adsorption. For instance, the adsorption capacity for methylene blue (MB) reached 87.9 mg/g, surpassing the performance of several biochar adsorbents. Besides, it was found that the adsorption performance of CTA carbons was better than that of Fe-PTA carbons which have larger specific surface area and such result was attributed to the rich acidic functional groups on CTA carbon surface. Moreover, used CTA carbons could be recovered efficiently by self-activating low-concentration peroxydisulfate, achieving the regeneration rate of 82 %. Our work offers a promising eco-friendly approach for CTA upcycling in textile industry.

Extraction and Fermentation of Sugars from Almond Hull to Produce Astaxanthin

Almond hull is one of major byproducts of almond industry. It is rich in fermentable sugars which can be extracted for value-added applications. This study optimized the fermentable sugar extraction from almond hull by using response surface methodology with Box-Behnken design to optimize the operating parameters, including temperature (30, 55, and 80°C), shaking speed (200, 400, and 600 rpm), and extraction time (10, 65, and 120 min). The results showed that temperature is the most significant factor and the maximum total fermentable sugar yield of 36 ± 0.1 g/L was achieved under the conditions of 120 min, 80°C and 600 rpm for at 10% (dry weight basis) almond hull loading. A second-degree polynomial model can accurately predict the TFS extraction (R2=0.71). The extracted sugars (i.e., almond hull extract - AHE) were fermented into a high-value antioxidant, astaxanthin by using a yeast, Xanthophyllomyces dendrorhous while the effect of the type of nitrogen source on astaxanthin production was investigated, including yeast extract/peptone, ammonium chloride, ammonium sulfate, and urea. Amongst, yeast extract/peptone with the synthetic AHE and ammonium chloride with the original AHE achieved the maximum astaxanthin concentration of 3.31 ± 0.22 mg/L and 2.05 ± 0.27 mg/L, respectively. Selecting proper nitrogen sources (e.g., ammonium chloride) could mitigate the inhibition on astaxanthin fermentation of the original AHE fermentation. Astaxanthin production is a potential value-added outlet for almond hulls and a profit opportunity for the almond industry.

One step resource utilization treatment of solid waste: Preparation of high-performance building bricks from calcium carbide slag by ultra-high mechanical pressure

Calcium carbide slag (CCS), a bulk solid waste byproduct of the energy industry. This paper introduced an innovative ultra-high pressure contact forming technology that utilizes 100% CCS under high pressure conditions ranging from 100 to 400 MPa. investigated the effects of pressing pressure and curing conditions on the comprehensive performance of the resulting bricks. The findings reveal that bricks subjected to autoclave curing for a duration of 3 days exhibit optimal mechanical and waterproof properties. The bricks demonstrated the compressive and flexural strength of 37 MPa and 4.3 MPa, and a softening coefficient of 0.89. Furthermore, the bricks' dry density, wet density, and porosity index were measured at 1200 kg/m3, 1600 kg/m3, and 1.3, respectively. Notably, the leaching concentrations of toxic and harmful elements within the bricks are in compliance with environmental standards. This research delineates a viable avenue for the future resourceful utilization of solid waste.

Approach to Design Sustainable Alkali-Activated Slag Recycled Aggregate Concrete: Mechanical and Microstructural Characterization

There is a steep increase in demand for concrete as the need for infrastructure is increasing with a rapid increase in urbanization. Consequently, there has been a surging demand for cement across the globe. By using alkaline concrete activated with ground granulated blast furnace slag (GGBS), cement usage can be eliminated in concrete, which addresses the issue of CO2 emissions concerned with the cement manufacturing process and promotes the use of industrial by-products as sustainable building materials. The current study focuses on proposing a methodology to design sustainable GGBS-based alkali-activated concrete incorporated with 100% coarse recycled coarse aggregates (RCA) recovered from construction and demolition (C&D), for various strengths by optimizing the mix proportions and verifying the same through experiments. From the current study, it is evident that this mix design procedure can be adopted to design alkali-activated slag recycled aggregate concrete (AASRAC) mixes for strengths ranging from 44MPa to 85MPa. The optimum values of alkalinity factor (λ) and NaOH concentration (M) i.e., 1.5 and 12, have a significant role in the development of high strengths which is attributed to the formation of hydrotalcite. Micrographs captured using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) studies reveal that the alkaline binders promote the development of a denser and stronger interfacial transition zone (ITZ) that enhances the strength of lower AA/B concretes at the microstructural level as Ca/Si ratio is higher for lower AA/B concretes. Global warming potential (GWP) analysis reveals that the alkali-activated concretes have significantly lower GWP compared to conventional OPC-based concrete by approximately 2.5 times. The mix-design chart proposed in this study may pave the way to designing structural grade AASRAC with enhanced performance for the desired strength, which may find its application in fast-track construction and manufacturing of prefabricated elements.

Gilthead seabream (Sparus aurata) fed with polar lipids from olive oil industry by-products: Shelf-life, microbiological and physicochemical characteristics during storage at 2oC

Gilthead seabream (Sparus aurata) fed with polar lipids from olive oil industry by-products: Shelf-life, microbiological and physicochemical characteristics during storage at 2oC

Integrating fiber with new cement trends to create a greener future for sustainable concrete

The need for innovation in the construction sector is increasingly pressing, propelled by rising environmental issues and the ongoing quest for structural efficiency. This study investigates the transformational potential of fiber-reinforced concrete (FRC), analyzing its ability to improve mechanical performance and promote environmental sustainability. By using diverse fibers, including natural, synthetic, and industrial waste fibers, FRC enhances qualities like as tensile strength, fracture resistance, and durability while promoting more sustainable building techniques. This research carefully explores current improvements in the processing and handling of various fibers and assesses their effects when integrated into concrete. Particular emphasis is placed on the use of recovered industrial by-products, including slag, fly ash, and recycled plastics, in conjunction with natural fibers such as bamboo, kenaf, and flax. These materials are recognized for both augmenting the structural integrity of concrete and substantially decreasing the carbon footprint of construction by lowering dependence on virgin resources and encouraging the recycling of industrial waste. Experimental investigations and life cycle evaluations were performed to measure the improvements in performance and sustainability provided by FRC. The study results indicate that FRC has enhanced durability and performance attributes, making it a suitable choice for both structural and non-structural applications. Moreover, the incorporation of sustainable fibers has shown a decrease in greenhouse gas emissions, consistent with international sustainability objectives. Nonetheless, the implementation of FRC encounters obstacles pertaining to the inconsistency of fiber characteristics, economic viability, and industrial scalability. Confronting these obstacles via continuous research and interdisciplinary cooperation is essential for the widespread adoption and use of FRC in the construction sector. This study emphasizes the significance of new materials, such as fiber-reinforced concrete, in promoting sustainable building methods, illustrating its potential to profoundly influence the future of construction regarding environmental responsibility and structural efficacy.

The fertility of urban ruins: Obsolete industrial cities as ecosystem holders to activate circular economy

This paper seeks to find poetry in recreating, if not beauty, then aesthetic dimension in waste itself, to find perfection in imperfection itself. The underline hypothesis stems from questions such as what is the relationship between the automotive industry and the building industry? What if there exists a knowledge transfer mechanism between the two. What if the know-how of automakers be applied to the building industry? Beyond adaptive reuse of existing buildings and abandoned structures, the image of the city of Detroit as the model of industrialized American city could be reshaped by the knowledge of its memory. This manuscript provides a speculative approach to revitalize one of the most famous examples of an American industrial city. The approach attempts to highlight the importance of activating multi-industry pollination known as industrial symbiosis (IS) specifically between the automotive industry and the building industry using the city of Detroit as a case study. Ideas to test the vitality of this approach were explored and tested in a graduate architectural design studio where students were challenged with transforming the automotive industry by-products, waste streams, and flows into building products and façade systems.

Photothermal Synergistic Hydrogen Production via a Fly-Ash-made Interfacial Vaporific System.

Employing UV-vis spectrum for hydrogen generation and vis-IR spectrum to elevate reaction temperatures and induce phase transitions effectively enhances yield and purifies water, demonstrating a judicious strategy for solar energy utilization. This study presents an interfacial photothermal water splitting system that utilizes all-inorganic, economical industrial by-products known as fly ash cenospheres (FAC) for solar-driven hydrogen generation. In this system, the yield reaches 254.8µmol h-1cm-1, representing an 89% augmentation compared to that of the three-phase system. In situ experiments, combined with theoretical calculation, reveal the system's robust light absorption capacity, facilitating rapid gas separation, thus improves the solar-to-hydrogen (STH) efficiency. Furthermore, the system demonstrates strong performance in turbid water and scalability for expansive applications, achieving a hydrogen yield exceeding 50 L h-1 m-2 from various water sources. Facilitating large-scale hydrogen production and water purification, it thereby establishing its potential as a viable solution for sustainable energy generation.

A novel application of industrial waste bischofite for the anti-aging property of asphalt: Synthesis of organic layered double hydroxide and performance evaluation

Asphalt aging causes significant distress to pavements, which risks driving safety and poses unsustainable repair and reconstruction works. Layered double hydroxide (LDH) is a promising anti-aging modifier for asphalt. A unique benefit of LDH is its potential raw material - bischofite, a fruitful by-product of salt lake industries and is often casually discarded. In this work, LDH with laminated structure and high crystallinity was synthesized from industrial waste bischofite, and the silane coupling agent A151 was grafted onto the LDH surface, which remarkably inhibits the adhesion and hydrophilicity of LDH and makes it more compatible with asphalt. Asphalt becomes hard and brittle after aging, and the rheological properties deteriorate considerably. At the micro-level, asphalt aging is manifested by the oxidation of light components to heavy ones, the increase of molecular weight, the accumulation of macromolecules, and the gelation of the colloidal structure. Comparative studies indicate that the LDH synthesized from waste bischofite is able to relieve performance deterioration, component oxidation, molecular polymerization, and structure gelation of asphalt during aging. Furthermore, the A151 surface organic modification can further improve the effect of LDH in bolstering the anti-aging property of asphalt. These favorable results provide a sustainable approach to building durable pavements.