Particle Size Of Raw Materials Research Articles

How does particle size of spent coffee ground affect the physicochemical properties of isolated cellulose nanosphere?

Studying the effect of raw material particle size on the properties of isolated nanocellulose is crucial for enhancing material performance, optimizing processing techniques, and promoting sustainability in various industrial applications. Therefore, this study aims to extract and characterize nanocellulose from spent coffee ground (SCG) with different particles size (A: 850–1000, B: 500–850, C: 350–500 μm). For this purpose, SCGs were purified using alkaline and bleaching agents to extract cellulose, followed by acid hydrolysis (sulfuric acid 64 %, 45 °C, 1 h) combined with ultrasonication treatment to produce nanocellulose. The obtained nanocelluloses were characterized in terms of morphology, size distribution, sulfur content, ζ-potential, crystallinity, crystal size, thermal stability, and re-dispersibility in water. Atomic force microscopy confirmed the production of spherical nanocellulose (CNS) with diameter ranging from 65.21 nm in A-CNS to 49.31 and 48.06 nm in B and C-CNS, respectively. The ζ-potential of fresh dispersions decreased with particle size, from −44 mV for A-CNS to −41 mV and −40 mV for B and C-CNS, respectively. The sulfur content also decreased gradually from 214.30 (A-CNS) to 191.29 mmol/kg (C-CNS). All CNS were relatively thermally stable, with thermal analysis showing enhanced stability for A-CNS. The crystallinity index (64–69 %) and the crystal size (2.21–2.39 nm) of CNS were not affected by the particle sizes. In summary, the CNS dimensions, ζ-potential of fresh dispersions, sulfur content and thermal stability of CNS varied significantly among samples, depending on the particle size of SCG. Therefore, it is strongly recommended that researchers choose the optimum particle size for producing nanocellulose for the desired applications.

Synthesis of geopolymer using glass fiber powder from retired wind blades: A new attempt to recycle solid waste in wind power industries

This study explores the potential of recycling and utilizing discarded wind turbine blades. It proposes a new method that upcycles the glass fiber powder (GFP) in these blades into geopolymer gel, offering a new solution for the recycling and treatment of retired wind blades. Analyses of the X-ray diffraction (XRD) pattern of the GFP raw material and its dissolution in concentrated alkali indicate a large content of vitreous and active silica-aluminum, suggesting its suitability for producing geopolymers through alkali activation. The effects of the alkali activator modulus (Ms), alkali-binder ratio (N/B), and water-binder ratio (w/b), raw material particle size, and initial curing temperature on the compressive strength of the specimens were comprehensively and systematically investigated. The reaction behavior, chemical structure, and microstructure of GFP-synthesized geopolymers were characterized by selective dissolution, microcalorimetry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). The results showed that gels were formed by the geopolymerization reaction between the GFP and alkali activator. The compressive strength of the specimens increased first and then decreased with increasing alkali activator Ms and N/B. However, increasing w/b led to a decrease in strength. Appropriately small particle sizes of the raw material and moderately increasing the initial curing temperature are beneficial to strengthen the compressive strength. The optimal 28 days compressive strength of 43.43 MPa was achieved with an activator Ms of 1.4, N/B of 10 %, w/b of 0.33, GFP with a D90 of 170 mesh, and an initial 24 h curing temperature of 60 °C. The results of this study can promote the utilization of waste wind blades in the production of sustainable building materials.

Improving pressurized liquid extraction of passion fruit (P. edulis) bagasse: Exploring the effects of high-temperature, particle size, and extraction bed dimensions

Extraction techniques to obtain bioactive molecules from passion fruit bagasse have emerged recently. The driving force behind this effort lies in the array of biological properties related to its compounds, including anti-carcinogenic, antioxidant, anti-inflammatory, and vasorelaxant properties. Given this background, this work proposes improvements to the extraction process from defatted passion fruit bagasse (DPFB). The effect of pressurized liquid extraction (PLE) temperature was examined at 70, 90, and 110 °C, revealing an increase in global yield and total reducing content (TRC) with rising temperature. However, the yield of piceatannol was statistically equal between 70 and 90 °C and decreased at 110 °C, suggesting thermal degradation. These findings were corroborated by thermal stability analysis and oxygen radical absorbance capacity assessment. The impact of raw material particle size was investigated and showed that granulometric classification led to an increase in the TRC and piceatannol yields by 35% and 84%, respectively, and allowed identifying the piceatannol's location within the outer layer of the passion fruit seed (FR1). Mathematical modelling was applied to the kinetic extraction of DPFB-FR1 to assess the effect of bed height to diameter ratio (H/D). The two-site desorption model has properly fitted experimental data and indicated an enhancement in piceatannol mass transfer rate when increasing H/D. In summary, the present work presents findings and conclusions not previously documented in the literature, contributing to the improvement of PLE and pre-treatment methods for passion fruit bagasse.

Fabrication of high-performance recrystallized silicon carbide ceramic membrane based on particle packing optimization

Overcoming the challenges associated with achieving high uniformity and connectivity of pore channels in ceramic membranes, we designed silicon carbide ceramic membrane derived from the recrystallization process based on the Dinger-Funk equation of the closest-packing model with various grain grading. Furthermore, the effects of particle size distribution on the resulting microstructure and pore architecture of the ceramic membrane was also explored. The findings corroborated the critical importance of raw material particle size distribution in controlling pore size distribution and morphology. After sintering at 1900°C, the silicon carbide ceramic membrane, benefiting from ideal particle packing, exhibited a remarkably uniform pore structure. Notably, the most probable pore size constituted over 70 %, while achieving an open porosity of 51.3 % even without the addition of pore-forming agents. The silicon carbide ceramic membrane also demonstrated exceptional hydrophilicity (water contact angle:∼0°), impressive water permeation (1210 L m−2 h−1·bar−1), coupled with efficient turbidity removal (∼100 %) in carbon black wastewater treatment applications. Additionally, membrane regeneration proved effective using a dilute NaOH solution backwash, achieving a flux recovery efficiency of 98 %. This strategy had directive significance for designing high-performing silicon carbide ceramic membranes.

A study on composite carbonaceous reducing agent pellets based on low-order unbonded coal

To minimize the cost of carbon-reducing agents and reduce the waste of powder in production, a novel composite carbonaceous reducing agent pellet was prepared through cold pressing, utilizing low-rank unbonded coal (NC) as the primary raw material and incorporating petroleum coke (PC) and high-bonding coal (HVC). This study investigated the influence of different material composition ratios, the addition of organic binder (OBD) and inorganic binder (IBD) (water glass solution), forming moisture ranging from 2 to 12 %, holding temperatures of 60 to 100 ℃, holding times of 2 to 6 h, and material particle sizes ranging from 40 to 250 mesh (0.063–0.420 mm). Additionally, forming pressures of 5 to 30 MPa were analyzed concerning their impact on the cold consolidation strength (CCS) of the resulting pellets. The primary and secondary effects of forming pressure, forming moisture, binder content, and raw material size on pellet strength were examined. According to the actual production situation, the optimum technological conditions were determined. The primary and secondary effects on CCS were ranked as follows: forming pressure > particle size of raw material > binder ratio of 4 % content > forming moisture. External morphology and internal structures of different carbon materials were characterized via FESEM, BET, FTIR, XRD, and XPS. Mechanisms affecting the pellet strength were analyzed. The newly developed composite carbon-reducing agent pellets were suitable for industrial silicon production. This study presented a pathway for the clean and efficient utilization of low-rank unbonded coal and low-viscosity coal, offering substantial economic and social benefits.

Characterization, performance evaluation and optimization of wheat straw – bagasse blended fuel pellets

This study was carried out to assess the fuel pellets produced from wheat straw and sugarcane bagasse. The wheat straw and bagasse were blended into four ratios including; 10:90, 30:70, 70:30 and 90:10 (wheat straw: bagasse) and developed into fuel pellets. The fuel pellets were characterized to determine the moisture content, volatile matter, fixed carbon, ash content, calorific value, bulk density and mechanical durability. The ignition time, burning rate and specific fuel consumption of the wheat straw – bagasse blended fuel pellets were studied at varying blend ratios (10:90, 30:70, 70:30 and 90:10), moisture contents (9.1%, 10.6%, 12.6% and 14.7%) and raw material particle sizes (2 mm, 4 mm, 6 mm and 10 mm). Results indicated that the wheat straw: bagasse blend ratios containing more proportion of bagasse (30:70 and 10:90) recorded a shorter ignition time, higher burning rate and lower specific fuel consumption. Larger raw material particle sizes exhibited shorter ignition time, higher burning rate and specific fuel consumption. Moreso, the fuel pellets with low moisture contents also recorded shorter ignition time, higher burning rate and lower specific fuel consumption. It was concluded that fuel pellets with high quantity of bagasse, large particle sizes and low moisture content demonstrated favorable combustion characteristics. Response surface methodology was used in the optimization so as to determine the optimum combination of blending ratio, moisture content and raw material particle size that would result in the lowest ignition time, highest burning rate and lowest specific fuel consumption. Results indicated that an optimum combination of a wheat straw: bagasse blend ratio of 10:90, moisture content of 14.70% and a particle size of 10.00 mm resulted in the lowest ignition time, highest burning rate and lowest specific fuel consumption.

A comprehensive study of melt foaming in E‐glass batch‐to‐melt conversion process: Effects of sulfate content and chemistry of raw materials

AbstractControl of sulfate‐induced melt fining without excessive foaming is one of the critical steps in maintaining the stability of E‐glass fiber manufacturing processes. Besides, the efficiency of combustion or energy utilization is directly affected by the extent of the melt‐foaming. A fundamental understanding of key factors affecting melt foaming under the simulated oxy‐fuel combustion environment will enable commercial E‐glass fiber production to optimize both batch chemistry and operation conditions to achieve adequate furnace control. In this study, six types of E‐glass batches with the same target glass composition were prepared by using four different CaO sources; calcined limes with different SO3 contents, limestone, limestone with sodium sulfate, and a mixture of limestone and calcined lime. All batch samples were examined by HTMOS‐EGA system (high temperature melting observation system with evolved gas analysis). HTMOS enables monitoring batch‐to‐melt conversation steps by using a high‐resolution camera and EGA detects the evolved reaction gaseous, such as CO, CO2, and SO2 via an Fourier transform infrared (FTIR) gas analyzer. Gases of water vapor, N2, and O2 were introduced accordingly into the fused quartz crucible to simulate similar oxy‐fuel atmosphere of the furnace operation. This study aimed to investigate the effects of different SO3 contents in batches and different raw material chemistries on the foam formation in E‐glass melts under the oxy‐fuel atmosphere. Different raw materials were characterized by mineralogical analysis, chemical analysis, particle size distribution, chemical oxygen demanding (COD) level, and Brunauer–Emmett–Teller (BET) analysis. Although some of the batches contained the same SO3 content, different foam formations resulted from the effect of the batch chemistry. Our detailed HTMOS‐EGA investigations show that not only SO3 content in the batch affects foam formation in E‐glass melts, but also raw material chemistry and particle size have strong effects on the melt foaming in E‐glass batch melting, especially for those of ingredients having hydroxide phases and/or finer particles with higher specific areas.

Study on Recovery of Lithium from Lithium-Containing Aluminum Electrolyte

The current process of recovering lithium from wasted aluminum electrolyte mostly entails extracting lithium from lithium-containing aluminum electrolyte by acid leaching and dissipation. Aiming at the disadvantages of the existing treatment method, such as the long process flow, environmental pollution, poor working environment, etc., we propose a new technology to extract lithium from the wasted aluminum electrolyte and systematically investigate the effects of raw material particle size, holding time, temperature and other factors on the recovery of lithium. The results show that the better process conditions for the recovery of lithium are as follows: the raw material particle size is 75~150 μm, the additive is CaCl2, the mass ratio of calcium chloride to lithium-containing aluminum electrolyte is 3:5, the reaction temperature is 1473 K, and the holding time is 3 h. After the product of the reaction is crushed and leaching is carried out by using deionized water (pH = 6.8), the temperature of the leaching is 368 K, the leaching time is 3 h, and the solid–liquid ratio is 1/3, and the leaching rate of Li can be up to 75.1%. In addition, the purity of the recovered AlF3 is more than 92.7%. This process realizes the comprehensive and efficient use of lithium-containing aluminum electrolyte and provides a new idea for the development of lithium extraction technology from lithium-containing aluminum electrolyte.

In Situ Ca‐ and Mg‐ Codoped Biochar Derived from Tobacco Stem for Phosphate Adsorption and Desorption

AbstractPhosphorus is an important element for plant growth. The efficient use and recovery of phosphorus is crucial due to limited phosphate resource reserves. This study explored the potential application of an in situ Ca and Mg co‐doped biochar derived from tobacco stem to reclaim and reuse phosphate from aqueous solutions. We performed various batch adsorption experiments and industrial analysis based on different parameters. The findings indicate that biochar prepared using the raw material particle size range of 0.85–2 mm and pyrolyzed at 800 °C presented good pore structure and specific surface area. Ca and Mg elements in biochar exhibited great influence on its phosphate adsorption property. The maximum phosphate adsorption capacity of the tobacco stem‐based biochar was 54.66 mg/g, and the experimental data agreed with the Langmuir equation, suggesting monolayer adsorption. The adsorption process conformed to the pseudo‐second‐order kinetic equation, indicating that chemisorption was the dominant adsorption process and that the adsorption was controlled by intra‐particle diffusion. Furthermore, phosphate adsorbed on tobacco stem‐based in situ Ca and Mg co‐doped biochar was released under acidic, alkaline, and neutral conditions. Therefore, in situ Ca and Mg co‐doped biochar prepared from tobacco stems is a potential environmentally friendly and low‐cost adsorbent for phosphorus recovery.

The Effect of Leaching Duration and Solid/Liquid Ratio on Lithium Extraction from Mica Schist Used Hydrochloric Acid Process

Lithium demand has increased rapidly in the last few years because lithium is a metal that is important in technology, like electronic equipment and electric vehicles. One of the primary lithium resources is lithium ore, which contains minerals such as spodumene and lepidolite. Mica schist is one of the lithium ore sources that is indicated to contain lithium. The mica schist used in this research was from Kebumen, Central Java, Indonesia. This raw material indicates a lithium mineral called lepidolite. The aims of this research were to find out the potential of local Indonesian minerals as raw materials for lithium extraction processes in lithium-ion battery (LiB) applications, with the effect of leaching time and solid/liquid ratio. The leaching agent used in this research was 2 M chloride acid (HCl). Variables of this research were-100 mesh for particle size of raw material, 1:5, 1:10, 1:15, and 1:20 (g/ml) for solid/liquid ratio, 30, 60, 90, and 120 minutes for leaching time, and 70 °C for leaching temperature. Inductively Coupled Plasma (ICP-OES) analysis was done on this research to determine the mica-schist composition. The optimum lithium percentage that was obtained in this research was 40.65% on a solid/liquid ratio of 1:5 (g/ml) and a leaching time of 120 minutes.

Kinetics of extracting valuable components from Ti-bearing blast furnace slag by acidolysis with sulphuric acid.

Ti-bearing blast furnace slag is a kind of solid waste produced by Pangang Group Company through the blast furnace smelting method. A variety of valuable components can be extracted from the Ti-bearing blast furnace slag after acidolysis with concentrated sulphuric acid. In order to study the kinetics of acidolysis, this paper investigated the effects of the acidolysis temperature, acid-slag ratio and raw material particle size on the overall extraction rate of Ti4+, Mg2+ and Al3+ components at different reaction times, and simulated the acidolysis process by using the unreacted shrinking core model. The results showed that the acidolysis process was controlled by internal diffusion with an apparent activation energy of 19.05kJmol-1 and the semi-empirical kinetic equation of the acidolysis process was obtained.

Effect of Non-Plastic Raw Materials Particle Size on Technological Properties of the Single-Fired Wall Tile Bodies

This study has investigated the effect of particle size of non-plastic components of quartz and pegmatite on some technological properties of wall tile bodies. For this, quartz-pegmatite mixtures were further milled up to 90 min. before adding into the body composition unlike the standard body composition, where quartz and pegmatite were used as-received. The physical and mechanical properties of the bodies were investigated and compared with the standard values. Thermal expansion coefficient and moisture expansion values were determined by a dilatometer. Phase analyses were carried out by X-ray diffraction and microstructural characteristics were studied using a scanning electron microscope. Changes in various technological properties with reducing particle size of the non-plastic components were reported, particularly the increased green and fired strength. It was discussed that using finer particle size non-plastic raw materials of quartz and pegmatite would enable not only increased industrial productivity but also increased producibility of thinner large format wall tiles.

Influence of Raw Material Size on the Microstructure of Graphene Oxide and Its Early Strengthening Properties of Cemen

With the purpose of exploring the influence of raw material size on the structure-performance of graphene oxide (GO) for cement reinforcement, this paper used natural flaked graphite with different particle sizes as raw material to prepare GO nanosheets by a method of enhanced Hummers, and then used scanning electron microscope (SEM) , X-ray diffraction (XRD) , Raman spectrum, infrared spectrum (IR) and other means to characterise the microstructure of GO products in detail, and then investigated the effects of raw material size and graphene oxide GO dosage on its early strengthening effect in cement. The experimental results showed that with the decrease of raw material particle size, the spacing between the layers of GO products is basically the same, while the oxidization degree is increased, and the oxygen-containing groups on the surface are increased. When the GO matt was used to prepare cement mortar with same GO extent, the mechanical strengths at an age of 3 days were found to initially increase and then decrease with the reduction of raw material particle size, and the GO products had the best effect on the improvement of early mechanical strength of cement when the raw material particle size was 13μm. On the other hand, GO matt being obtained from the raw material particles in a size of 13μm was employed to prepare cement mortar with different GO content, of which the 3d strength was found to increase apparently with the increasing GO content, and thus resulted in the increment of 8. 85% to the 3d compressive strength and 6. 34% to the 3d flexural strength for the mortar specimen obtained with a GO content of about 0. 05%, but the further increasing of the GO content is not proposed, which might gave rise of a relative low mechanical strength.

Moroccan Citrus clementina Peels: Optimization of Pectin Extraction and Determination of Chemical and Functional Properties.

Citrus peels are considered a rich source of valuable biomolecules. Pectin is a polymer of polysaccharide acid and is composed of galacturonic acid monosaccharides. In this study, response surface methodology was used to optimize pectin extraction from Citrus × clementina Hort. ex Tan. (Rutaceae) peels using citric acid as an extraction solvent. The effect of the parameters conditioning the extraction process and pectin yield (pH level, temperature, extraction time, solid/liquid ratio, and raw material particle size) was investigated using a Box-Behnken design. The quality of the extracted pectin was assessed both chemically (moisture, ash, protein, and carbohydrate content) and functionally (gelling power and emulsifying activity). According to the screening experiment, the pH level, temperature, and particle size were the main factors influencing the pectin yield. The adjusted mathematical model enabled us to plot response surfaces in order to determine the optimal extraction conditions. The highest production yield of pectin (26.6%) was obtained at the optimal conditions of pH = 1.5, temperature = 100 °C, and particle size = 0.1 mm for an extraction time of 30 min. Compared to the predicted value of 26.6%, the experimental extraction yield of C. clementina was about 21.4% of pectin. Concerning the functional properties, the extracted pectin had a high gelling power of 164 ° SAG and an emulsifying activity of 38.5%.

Preparation of high-performance M-type strontium hexaferrites by ceramic method by optimizing the particle size of raw materials

High-performance strontium hexaferrites (SrM) was prepared by optimizing the particle size of strontium carbonate (SrCO3) and iron oxide (Fe2O3). The microstructure, morphology, particle size and magnetic properties of as-prepared strontium hexaferrite have been examined. The results showed that fine SrCO3 and Fe2O3 powders enhanced reactivity and lowered the starting temperature of the reaction. Magnetic result showed that as-prepared strontium hexaferrite with large saturation magnetization and high coercive force was fabricated by using fine SrCO3 and Fe2O3 powder. The optimum value of saturation magnetization (MS) and coercive force (HC) are 78.97emu/g and 5019Oe respectively. This study facilitated an energy-saving strategy for large-scale production of high-performance strontium hexaferrites in the future.

Use of Post-Consumer Plastics in the Production of Wood-Plastic Composites for Building Components: A Systematic Review

This systematic review study adopted the PRISMA methodology to investigate recent research on wood-plastic composites (WPC) utilizing post-consumer plastics in the construction industry. Initially, 3111 articles were selected from academic databases using keywords such as “wood and plastic composites”, “WPC”, “polymer”, “recycled”, “waste”, “construction”, and “sustainability.” After stringent exclusion criteria, 15 relevant studies on plastic waste composites were identified. These studies often employ post-consumer plastics like polypropylene and high-density polyethylene, along with plant-based fillers, aiming to enhance mechanical properties and reduce reliance on virgin materials. Analysis of these studies revealed that the optimal plastic composition in the composites ranged from 40% to 45% wood and from 50% to 60% plastic, with the extrusion process being the most employed for shaping. Specific factors, such as the use of compatibilizers and the particle size of raw materials, were identified as significant influencers on composite strength. These materials exhibited high thermal stability, rendering them suitable for construction applications exposed to high temperatures. The diversity of plastic waste explored in the studies underscores the potential to tailor thermal properties to specific application demands. These composites facilitate closed-loop plastic recycling, enabling their reintegration into the production chain and offering opportunities for lightweight, durable, and high-performance products in the construction industry. However, beyond the factors examined in the studies, a meticulous assessment of the fire resistance, weather resistance, ultraviolet resistance, moisture absorption, dimensional stability, degradation, long-term durability, impact strength, recyclability, and cost-effectiveness of the material is crucial. Thoughtful consideration of these factors is essential to achieving a comprehensive understanding of the potential and limitations of recycled plastic composites in promoting energy efficiency and sustainability in the construction industry.

Comparison of conventional crushing and high-voltage pulsed power technology as techniques for disaggregating different types of spent magnesia-carbon refractory bricks during recycling

Three different types of spent magnesia-carbon (MgO–C) bricks were chosen to evaluate the liberation of magnesia particles through high-voltage pulsed power technology (HVPPT) and conventional comminution (jaw and cone crushing). The primary objective was to determine how the different types of MgO–C bricks comminute and whether magnesia particles could be restored to their original raw material particle size distribution (PSD).Analytical results revealed that the bricks contained varying amounts of graphite and resin binder, indicating differences in their compositions and therefore comminution properties. The HVPP technique demonstrated its ability to liberate magnesia particles within the +1700 μm fraction, whereas conventional crushing predominantly formed composite particles (containing MgO and carbon) within this size range, with over 63% particles falling in this category. This finding suggests that MgO particles were not adequately liberated during the conventional crushing process, indicating the need for an additional comminution step to achieve the desired liberation.

Feasibility of high-magnesium nickel slag-fly ash as precursor of magnesium phosphate cement and its hydration mechanism

The aim of this study was to investigate the process conditions, hydration reaction products and mechanism of high-magnesium nickel slag (HMNS)-fly ash (FA) as a precursor of magnesium phosphate cement (MPC). The relationships between properties, hydration products, hydration processes, and micromorphology were investigated by engineering properties, XRD, TG-DSC, FT-IR, Raman, and SEM/EDS. The results showed that the optimal process (HMNS/FA = 1.0/0, NH4H2PO4 dosing of 25 wt%, water-cement ratio of 0.26, the maintenance condition is air maintenance, and 200 mesh particle size of raw materials) prepared the cementitious material with 28 d compressive strength of 58.00 MPa and linear expansion rate of only 2.5 %. The hydration process was a multi-stage process, including the dissolution of NH4H2PO4 and pre-treated HMNS (WHMNS), the precipitation of intermediate hydration products and the formation of struvite, and the formation of gelling phases such as -Si-O-P-, -Al-O-P-, and -Si-O-Al-O-P-. Eventually, a high-strength gel-crystal phase structure consisting of gelling phases such as struvite wrapped around unreacted raw materials and struvite crystals was formed. FA was harmful for cementitious material, and impurities and high levels of Ca in FA reacted with phosphate to form hydration products with a loose porous structure (e.g., brushite). The optimal process sample complies with the 52.5R grade of ordinary Portland cement (GB175-2007); its embodied energy was reduced by more than 73.4 % compared to magnesium phosphate cement (MPC), and the corresponding CO2 emission was reduced by more than 74.2 %. Therefore, it has the potential to partially replace MPC from the environmental and feasibility point of view.

Fine Fireclay (FC) technological properties and mineralogy by tuning body composition and raw materials particle size distribution

The Fire-Clay (FC) technology is being revised to cope with challenges involving difficulties in the supplying chains and need to optimize the reuse of waste from production. In this view, the effects induced onto the fundamental FC-ceramic reactions by the introduction of waste from Fire-Clay and Vitreous-China productions are investigated, as a function of the secondary raw materials’ particle size (s) in partial replacement of traditional chamotte. Complex interwoven reactions take place upon changing s, pointing to a general improvement of greification with a reduction of s and increase of the glass content. The role of small nepheline syenite contents (<5 wt%) is also analyzed, leading to relevant effects on greification and thermal expansion. All this opens a chance of introducing waste up to 20–25 wt%, thus providing a relevant contribution to a sustainable production and mitigation of natural resources exploitation.

Evaluation indexes of poplar sawdust and alfalfa grass forming pellets

An experimental study was conducted to obtain the degree and pattern of influence of the interaction of various test factors on the evaluation indexes of biomass-forming pellets and the optimal combination of test parameters. Poplar sawdust and alfalfa grass were crushed and compressed into pellets, which were used as test samples. The particle size and moisture contents of the biomass raw materials were selected as test factors, and the quality and performance evaluation indexes, such as relaxation density, Shore hardness, water resistance, crush resistance, longitudinal dimensional stability, forming rate, and productivity, were measured for each pellet group. The results showed that for the same biomass raw material, when the particle size range is zero to 1.5 mm and the moisture content is at 15%, the relaxation density, Shore hardness, and forming rate of the formed pellets are the greatest, and the crush resistance, water resistance, and longitudinal dimensional stability are the strongest. When the particle size range is about 4 to 5.5 mm and the moisture content is at 5%, the relaxation density, Shore hardness, and forming rate of the pellets are the smallest, and the crush resistance, water resistance, and longitudinal dimensional stability are the weakest. The best moisture content of the pellets is about 15%.