Search Results (65)

Barro Alto processes nickel laterite ore using rotary kilns and six-in-line rectangular electric arc furnaces. This study evaluated the briquetting of ferronickel ore to reduce kiln fines, improve furnace charge permeability, and enhance process safety. Binderless briquettes were produced from screened ore at two size fractions (−6.3 mm and −12.5 mm), with moisture contents of 16% and 24%, cured under closed and open conditions. The physical and metallurgical properties of the briquettes were assessed using ISO standard tests. The results confirmed successful agglomeration of the ore into binderless briquettes. Screening the run-of-mine (ROM) ore improved the feed quality, increasing the NiO grade from 2.0% to 2.2% in the −6.3 mm fraction. The briquettes from the −6.3 mm ore at 16% moisture exhibited the highest green strength (559 N). Higher moisture content reduced the briquette strength and increased both the reduction disintegration and decrepitation indices. The decrepitation index increased from 0.33% to 0.61% for the −6.3 mm briquettes when the moisture increased from 16% to 24%. The reduction levels were 33.4% and 39.2% for −6.3 mm and −12.5 mm briquettes with 16% moisture, respectively. This study concludes that optimal performance was achieved using −6.3 mm ore, 16% moisture, and open curing, thereby balancing reduction efficiency and mechanical stability. Full article

The generation of fine coal particles during mining and processing presents significant environmental and logistical challenges, particularly in coal-dependent, developing countries like South Africa (SA). This review critically evaluates the technical viability of fine coal briquetting as a sustainable waste-to-energy solution within a SA context, while drawing from global best practices and comparative benchmarks. It examines abundant feedstocks that can be used for valorization strategies, including fine coal and agricultural biomass residues. Furthermore, binder types, manufacturing parameters, and quality optimization strategies that influence briquette performance are assessed. The co-densification of fine coal with biomass offers a means to enhance combustion efficiency, reduce dust emissions, and convert low-value waste into a high-calorific, manageable fuel. Attention is also given to briquette testing standards (i.e., South African Bureau of Standards, ASTM International, and International Organization of Standardization) and end-use applications across domestic, industrial, and off-grid settings. Moreover, the review explores socio-economic implications, including rural job creation, energy poverty alleviation, and the potential role of briquetting in SA’s ‘Just Energy Transition’ (JET). This paper uniquely integrates technical analysis with policy relevance, rural energy needs, and practical challenges specific to South Africa, while offering a structured framework for bio-coal briquetting adoption in developing countries. While technical and economic barriers remain, such as binder costs and feedstock variability, the integration of briquetting into circular economy frameworks represents a promising path toward cleaner, decentralized energy and coal waste valorization. Full article

Lignocellulosic biomass is an exciting renewable resource for producing sustainable biofuels, thanks to its abundance and low environmental impact. However, its intricate structure makes it tough for enzymes to break it down effectively. Only efficient pretreatment methods can solve these problems. Among these, mechanical pretreatment methods are particularly good for industry because they are easy to use, do not require chemicals, and make it easier to achieve biomass. This systematic review adhered to the PRISMA protocols and used text analysis with VOSviewer to examine 33 academic articles published between 2005 and 2025. It highlighted two main types of mechanical pretreatment: size reduction (which includes grinding, crushing, and shredding) and densification (like pelletizing and briquetting). The results show that mechanical pretreatment can significantly boost biofuel yields by increasing surface area, lowering crystallinity, and allowing better enzyme penetration. Energy consumption remains a major hurdle for the overall sustainability of biomass conversion processes. This research provides a comprehensive review of current mechanical techniques, detailing their operational settings and performance metrics while also offering suggestions for optimizing biomass conversion processes. By promoting the use of mechanical pretreatment in biofuel production systems, the findings align with the principles of a circular economy and contribute to the development of greener energy sources. Full article

The development of biofuels aligned with the circular economy has gained increasing attention as a sustainable alternative to non-renewable energy sources. This study aims to evaluate the physical and thermal properties of biomass briquettes derived from potato stalk residues to assess their potential as biofuels. For this, dried potato stalk residues were subjected to pyrolysis for carbonization, followed by grinding and mixing with potato and achira binders in proportions of 10% and 20%, respectively. The briquetting process was performed at a pressure of 10 MPa with compaction times of 30 and 60 s. Scanning electron microscopy (SEM) revealed a porous structure with uniform binder distribution, while Raman spectroscopy confirmed the presence of D and G bands, indicative of amorphous carbon structures with graphite-like imperfections. Thermogravimetric analysis (TGA) determined a moisture content of 10%, which ensures stability. Non-carbonized briquettes exhibited higher compressive strength, withstanding forces in excess of 400 N at 20% deformation. The average calorific value of both briquette types was 15 MJ/kg, comparable to biofuels derived from sugarcane bagasse and rice hulls, with samples exceeding the 12 MJ/kg threshold for biomass fuel classification. These results indicate that potato stalk briquettes could be a viable biofuel alternative to support renewable energy diversification. Full article

The article provides a brief overview of technologies and methods for processing dispersed metallic waste generated during ferroalloy production, including high-carbon ferrochrome (HCFeCr). It is noted that the most cost-effective and rational method for reusing metallic dust is briquetting. Considering the development of briquetting technologies, as well as the latest equipment and binder materials involved in this process, aspiration dust from ferrochrome crushing can be fully utilized in metallurgical recycling. To verify this assumption, laboratory studies were conducted using polymer-based binders and liquid glass as a baseline option. The methodology of briquetting using both laboratory and industrial presses is described, along with an assessment of the mechanical properties of the briquettes. The studies indicate that the introduction of an inert filler (gas-cleaning dust) into the metallic dust composition improves the briquetting ability of the mixture by enhancing adhesion between metal particles and the binder. The obtained industrial briquette samples exhibit high mechanical strength, ensuring their further use in metallurgical processing. The study concludes that semi-dry briquetting using hydraulic vibropresses is a promising approach for the utilization of dispersed ferroalloy waste. Full article

In this study, the authors investigated the briquetting of hydroxyapatite and fluorapatite rock material and evaluated the properties of briquettes prepared in a roller press. This was conducted 10 years after the manufacturing process took place. These rocks are a primary source of the mineral phosphorus, for which demand is high, particularly in agriculture. The proper handling of the material in the industry is required due to its high environmental impact. In order to correctly identify the subject of this study, the authors analyzed its composition using energy-dispersive X-ray spectroscopy, scanning electron microscopy and polarized light microscopy. Afterwards, the authors analyzed the properties of the saddle-shaped briquettes, including their surface roughness (Ra, Rq, Rt), surface Leeb hardness distribution, porosity and density. The briquettes exhibited relatively large Ra values (mean 9.67 µm). The highest hardness was registered at the specimen center (61 HV5), whereas the lowest was at the edge (25 HV5). A high density of 2.51 g/cm³ was achieved in the process. It was possible to obtain saddle-shaped briquettes with reproductible properties, high density (porosity of 21%) and durability without using a binder additive. The study demonstrated that roller press briquetting can be successfully utilized as a method for compacting phosphate-bearing materials for the purpose of storage transportation and further processing. Full article

This research analyzes the technical feasibility and implementation of an appropriate technology for the production of briquettes from Pinus spp. waste (sawdust and shavings) in a rural community in Michoacán, Mexico. The results indicate that local small-scale briquette production in the Pichátaro community has the potential to boost a local economy based on the manufacturing and marketing of densified solid biofuels. The design of the manual briquetting machine was developed through a participatory approach with community users. Structural simplicity and locally accessible maintenance were prioritized, the aspects that were addressed little in previous studies. The machine allows for the production of briquettes using a low-cost mixture composed of sawdust and Pinus spp. shavings, corn starch, and water. Based on local conditions and production needs, parameters such as reduced processing times and simplified manufacturing methods were identified as essential to establishing an efficient regional production and supply chain. Furthermore, the valorization of solid waste through the production of alternative biofuels contributes to the diversification of the energy matrix in rural residential sectors and small industries in communities in Mexico. The estimated cost of the machine is USD 75.44, and most of its components are easily replaceable, which favors its sustainability and prolonged use. This study demonstrates that the implementation of a low-pressure briquette system based on appropriate rural technologies represents a viable strategy for the use of wood waste and the promotion of sustainable energy solutions in rural communities. Full article

Fine classes of metal dust generated during the production of ferroalloys increase the likelihood of irretrievable losses, creating the prerequisites for the development of rational methods for processing this material. One of the known technologies for recycling dispersed raw materials in metallurgical processing is their direct remelting. Although this technology is easily feasible, it has several significant drawbacks, among which the main problem remains the high dust carryover of fine material by ascending gas-thermal flows. A potential solution could be the preliminary preparation of raw materials through agglomeration. Domestic enterprises producing various types of ferroalloys have the necessary infrastructure and equipment for agglomerating dispersed ore materials, but the lack of experience and resource-saving technologies for processing metal dust prevents their full integration into metallurgical processing. In this regard, there is significant interest and demand from ferroalloy enterprises for the development of new methods to involve dispersed metal production waste in secondary recycling, adapted to existing agglomeration equipment. Numerous studies have shown that the cheapest method of agglomeration is briquetting. Given the advancement of briquetting technologies, as well as the use of the latest equipment and binding materials in this process, it can be assumed that this will allow for more complete integration of aspiration dust from ferrochrome crushing into metallurgical processing. To test this assumption, studies were conducted on the physicochemical properties of aspiration dust from ferrochrome crushing, assessing the possibility of obtaining an agglomerated product with the required strength parameters. The results of these studies demonstrated the fundamental possibility of producing high-carbon ferrochrome from briquetted material made from aspiration dust of ferrochrome crushing. Full article

The foundry industry is an industry with a large production of waste. One such type of waste is fine-grained to dust-like waste, depending on the stage of the foundry process in which it is generated. As part of this research, dust samples were collected from three Slovak foundries producing castings from gray iron, ductile iron, and steel. The aim of the experiments was to recycle iron from dust materials in the foundry process. Based on the chemical composition of the dust, samples with the highest iron content were selected and added to the charge of the electric induction furnace (EIF). Since it was not possible to add dust material directly into the EIF, the dust was modified by pelletizing and briquetting using three types of binders selected according to the foundries’ requirements. Pellets were prepared using dust from only one type of foundry waste and were used as part of the charge in the EIF. In the case of briquetting, different binder contents in the briquette mixture were tested to evaluate their effect on the strength and disintegration of the briquettes. Based on the foundries’ requirements that the binder had to be low-cost and that we had to not contaminate the melt (thus requiring a minimal amount), not affect the furnace operation, and not degrade the properties of the produced cast iron, briquettes with the best properties were selected and used as part of the charge for cast iron production. Samples of the cast iron produced this way were taken for chemical analysis, and specimens were prepared for tensile strength testing. The results showed that the use of briquettes, in limited amounts, did not have a negative impact on the chemical composition of the cast iron, the melting process, or its tensile strength. Full article

This article aims to provide a comprehensive review of the use of logging residues in manufacturing briquettes, and to demonstrate their potential as a renewable energy source. Technical aspects of briquetting are examined, including wood properties, particle size, moisture content, and process temperature. Forest residues, such as branches and treetops, have a high energy potential with calorific values reaching up to 20 MJ∙kg⁻¹ after briquetting. Densifying these residues increases their energy density (achieving up to 1120 kg∙m⁻³) and reduces waste and greenhouse gas emissions. Briquetting processes were analyzed economically and environmentally, with studies showing that production costs can be reduced by 25% when using locally sourced residues. This review recommends optimizing production processes to improve briquette durability and quality. Future research directions focused on developing cost-effective briquetting technologies tailored for small- and medium-sized businesses are identified in the study. Rural and economically disadvantaged regions could benefit from these advancements in briquetting. This paper advocates improved collaboration with international organizations to standardize briquette quality, promoting market acceptance and trade. Technology such as briquetting has the potential to advance renewable energy systems and achieve global climate goals. Full article

The current intensive development of steelmaking is being impeded by a scarcity of pure scrap. The potential to replace pure scrap with metallized raw materials that are naturally alloyed with vanadium and titanium, such as annealed unfluxed titanomagnetite pellets, could facilitate the achievement of key objectives in metallurgical development, particularly in the smelting of electric steel. The objective of this research was to produce annealed and metallized pellets from titanomagnetite concentrate under laboratory conditions, with the intention of further processing them as a commercial product in a blast furnace or as an intermediate product for the production of hot briquetted iron (HBI). The results demonstrate that pellets derived from titanomagnetite concentrate exhibit sufficient compressive strength (up to 300 kg/pellet) and a degree of metallization exceeding 90%, which aligns with the requirements for electric steelmaking. The suitability of pellets derived from titanomagnetite concentrate for use in both blast furnaces and metallization processes has been corroborated. Full article

This paper presents the results of optimizing the physicochemical properties of microsilica-based composite briquettes for metallurgical-grade silicon production. Microsilica, a waste product of silicon production, contains a sufficiently high amount of silicon dioxide (96–97%). This fact makes microsilica a promising composite material for metallurgical processing. However, its granulometric composition limits its direct use. The method of briquetting on an industrial briquetting press was used. The influence of the granulometric composition of the composite mixture on the heat tolerance and reactivity of the finished briquettes was studied. The methods of obtaining and testing the briquettes, their composition, and the briquetting and drying process were described. The obtained briquettes were tested for the smelting of metallurgical silicon. The silicon recovery rate in the metal with the standard charge was 71%, while the recovery rate with the briquetted monocharge was 85%. The results of silicon smelting from the briquettes demonstrated the high quality of the obtained metal, corresponding to the standards of metallurgical-grade silicon. The implementation of these technologies improves the quality of the finished product and addresses environmental issues related to the disposal of microsilica, reducing its accumulation and minimizing its impact on the environment. Full article

The melting of scrap and hot briquetted iron (HBI) in an AC electric arc furnace (EAF) is simulated by an advanced 3D computational fluid dynamics (CFD) model that captures the arc heating, the scrap/HBI melting process, and the solid collapse mechanisms. The CFD model is used to simulate a scenario where charge layering and EAF power profiles are provided by a real EAF operation. CFD simulation of the EAF operation shows proper prediction of the charge melting when compared with standard industry practice. Namely, the CFD model predicts a 32.5%/67.5% ratio of solid/liquid steel at the beginning of refining, which approaches the 30%/70% ratio used in standard practice. Based on this prediction, the melting rate in the CFD results differs by 8.3% from actual EAF operation. The impact of charge layering on melting is also investigated. CFD results show that distributing charge material into a greater number of layers in the first bucket (10 layers as compared to 4) enhances the melting rate by 12%. However, including dense material at the bottom of the furnace deteriorates melting performance, reducing the impact of the number of layers of the charge. The CFD platform can be used to optimize the use of HBI/scrap in real EAF operations and to determine best recipe practices. Full article

As a by-product of wastewater treatment, sewage sludge can be used for natural, agricultural, or energy purposes. One method of preparing sludge for management and use is solar drying. To intensify the drying process, natural additives can be used to alter the structure of the sludge and accelerate the evaporation of water. This research aimed to evaluate the influences of different organic additives in sewage sludge mixtures on the physicochemical and energy parameters of briquettes. This research was carried out without thermal boosting in a 4 × 2.5 × 2 m plastic tunnel. The tunnel was equipped with three drying stations and control and measuring equipment. In two test series, sludge additives in the form of straw and lignocellulosic materials, sawdust, bark, woodchips, and walnut shells, were used. Briquettes were made from the resulting mixtures and then subjected to physical and chemical analyses. This research showed high variability in the contents of trace elements, nitrogen, and sulphur in relation to an increase in the amount of sludge in the briquettes, which, for the briquettes made from sewage sludge, was nearly twice as high as for the briquettes made from the mixtures. The results of the flue gas analysis for the briquettes with sawdust and wood chip additives were very similar. The briquettes made from sewage sludge with lignocellulosic materials (bark and wood chips) had fuel properties similar to woody biomass, with a calorific value and heat of combustion of 15–16 MJ/kg. Fibrous additives (straw) significantly increased the strength parameters of the briquettes, by more than 50% of the value. The compositions and properties of the mixtures affected the following briquetting parameters: temperature and compressive force. The briquettes made from sewage sludge and additives can be classified according to ISO 21640 as SRFs (solid recovered fuels). In most of the results, the net calorific value (NCV) was 3 to 4; the chlorine content (CL) was 2 to 1; and the mercury content (Hg) was 1. The sewage sludge mixtures facilitated the agricultural and energy use of the briquettes. Full article

Currently, enterprises producing crystalline silicon are facing the formation and accumulation of large volumes of microsilica, a technogenic dusty waste formed during the melting of silicon alloys. Due to its chemical composition, this waste can be a significant raw material for metallurgical production. Therefore, this study is aimed to solve the problem of recycling microsilica. For these studies, a technology for the combined briquetting of microsilica and a carbonaceous reducing agent was developed for the production of a pilot batch of briquettes. This paper presents the results obtained from the process of testing the melting of crystalline (technical) silicon from briquetted monocharge obtained from microsilica. The tests were conducted under large-scale laboratory conditions on a 200 kVA ore-thermal furnace, where 30, 50, and 100% replacements of the traditional charge mixture with briquettes were tested. The results of this study showed that briquettes in the melting process of technical silicon can be successfully used in the range of 0 to 50%. The use of briquettes can significantly improve the technological indicators. The maximum extraction of silicon (approximately 83%) was achieved at 30% replacement. The technical and economic indicators of the process also improved. In particular, an increase in productivity was observed in comparison with tests on a traditional charge. Full article