Search Results (126)

Replacing clinker with mixtures of calcined clay and limestone is one of the most sustainable strategies for decarbonizing the cement industry. However, the kinetic patterns governing the grinding behavior of these materials are not yet fully understood. This study developed a kinetic model based on particle population balance to simulate this process. Experiments were conducted using a standard Bond ball mill, and the samples were characterized by X-ray diffraction. The results show that the grinding of calcined clay and its mixtures with limestone follows first-order kinetics. The proposed model simulates the process with a high degree of accuracy, with residual errors below 1.5% and a coefficient of determination exceeding 99%. Full article

Background: This study proposes a cascade strategy for the comprehensive valorization of Rosa canina L. leaves, considered an underutilized agricultural by-product. Methods: The approach is based on a combination of optimized Ultrasound-assisted extraction (UAE) followed by High-pressure homogenization (HPH) of the residual biomass from both whole and ground leaves. UAE parameters (temperature, process duration, and ethanol concentration) were optimized to maximize the yield of total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (DPPH, FRAP). Results: The optimal conditions (55.5 °C, 69.7 min, 40.8% ethanol) yielded extracts with a high TPC (289.55 mg GAE/g) and TFC (177.88 mg CE/g), reducing the processing time by 22% while increasing the TPC yield by 31% compared to the conventional solid–liquid extraction (SLE). It was found that primary extraction from whole leaves is more efficient than extraction from ground leaves, suggesting that the energy-intensive preliminary grinding step could be eliminated. The application of HPH to the residual biomass provided a significant secondary release of bioactive compounds, exceeding high-shear mixing (HSM) by up to 1.5 times for whole leaves. Kinetic analysis showed a higher release of bioactive compounds from whole leaves compared to ground leaves. Conclusions: The proposed UAE + HPH cascade process is a sustainable approach, ensuring rational use of resources and a significant increase in the total yield of antioxidants from Rosa canina L. leaves. Overall, the study may contribute to the circular economy by promoting valorization of agricultural by-products through an energy-efficient, sustainable cascade approach. Full article

This review systematically analyzes the technological progress, structural characteristics, and performance disparities among various diamond grinding wheel bond systems, aiming to establish a unified performance evaluation framework. This framework clarifies material selection criteria and highlights promising research directions. Eight prevalent bond systems are encompassed: resin, metal, ceramic, brazing, electroplating, composite, additive manufacturing, and glass-ceramics. A comparative analysis of these systems is conducted across multiple dimensions. Key evaluation metrics primarily include bond strength, thermal stability, self-sharpening capability, thermal conductivity, and formability. Considerable variations in these indicators are observed across the different bonding agents. Each system presents distinct advantages alongside inherent limitations. Within the constructed multi-metric framework, glass-ceramic bonding agents demonstrate high comprehensive potential in critical aspects such as bond strength and thermal stability, underscoring their research value as a novel high-performance bond system. Current primary challenges focus on the regulation of crystallization kinetics, the design of interfacial reaction layers, and multiscale performance prediction. Future research may advance along several paths. Synergistic design of material composition and microstructure is essential, while in-depth investigation into multiphysics coupling mechanisms remains necessary. Furthermore, data-driven material optimization methods are poised to unlock new possibilities for bond development. These approaches are expected to facilitate the precise design and application of high-performance diamond grinding wheel bonds. Full article

The increasing discharge of synthetic dyes into industrial wastewater necessitates sustainable and low-cost treatment strategies. This study valorizes orange seed powder (OSP), an abundant agro-food residue, as a novel biosorbent for Congo red (CR) removal through a combined experimental and molecular simulation approach. Raw OSP was prepared solely by drying and grinding, without chemical activation, emphasizing its practical applicability and environmental sustainability. Physicochemical characterization using FTIR, SEM, and EDX confirmed adsorption-induced structural and compositional changes. Batch experiments evaluated the effects of initial dye concentration, adsorbent dosage, pH, temperature, and contact time. Equilibrium data were well fitted by the Langmuir and Freundlich isotherm models (R² ≈ 0.99), with a maximum adsorption capacity of 258.39 mg g⁻¹ at 25 °C and pH 4, and a removal efficiency exceeding 99.55%. The adsorption kinetics followed a pseudo-second-order model, while intraparticle diffusion contributed to the rate-controlling mechanism, as indicated by the Weber–Morris model. OSP demonstrated excellent regeneration performance over five adsorption–desorption cycles, retaining more than 96% of its initial CR removal efficiency when regenerated with methanol. Grand Canonical Monte Carlo (GCMC) simulations revealed that adsorption is primarily driven by electrostatic interactions, hydrogen bonding, and π–π stacking interactions, in good agreement with the experimental findings. Overall, raw OSP represents an efficient, regenerable, and sustainable biosorbent, highlighting the originality of integrating experimental investigations with GCMC simulations for wastewater treatment applications. Full article

Background: The key parameters determining the bioavailability of an active pharmaceutical ingredient are its solubility/dissolution rate in physiological fluids and permeability across biological membranes. Highly accurate in vitro prediction of bioavailability is a key issue that typically arises during the development of new drug formulations and the improvement of existing ones. Objectives: The objective of the present work is to study the dissolution/release and permeation of olanzapine (OLZ) from two- and three-component solid dispersions (SDs) with sulfobutylether-β-cyclodextrin (SBE-β-CD) and several pharmaceutical adjuvants as solubilizing agents. Methods: Solid dispersions were prepared by mechanical grinding and characterized with X-ray Phase analysis (PXRD), Fourier Transform Infrared (FTIR) and Raman spectroscopy, Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM). Results: Raman spectroscopy was shown to be the best for revealing the interactions of OLZ with SBE-β-CD and γ-aminobutyric acid (GABA) in the three-component SD. The kinetic dependences of OLZ release and diffusion through the cellulose membrane were thoroughly described by quantitative parameters and classified according to the drug release mechanism. Significant improvement of release rate, OLZ concentration, and permeation with SDs compared to the pure OLZ was demonstrated. Conclusions: It was shown that the selected dispersions were stable when stored under normal conditions but underwent changes upon exposure to elevated temperature and humidity. The nature of these changes was determined by the properties of the components and their mutual interactions. Full article

Flotation circuits typically incorporate grinding stages, yet mathematical models for these processes often operate on different principles, leading to misalignment in circuit design. Building on a previously established grinding model for flotation performance, this research introduces significant advances to develop a more comprehensive and industrially relevant framework. The primary innovation is the integration of mechanical entrainment and gangue recovery into the kinetic model, distinguishing between species captured by true flotation and those carried to the surface despite being non-hydrophobic. We developed a robust set of grinding-mill equations based on first-order kinetics to describe the mass-fraction transformation of both true-flotation and entrainment species. To ensure practical applicability, a systematic experimental and modeling methodology for parameter adjustment is introduced, providing a clear sequence for identifying breakage rate constants and flotation kinetic parameters. The proposed strategy was validated using two distinct case studies: an expanded analysis of a copper sulfide ore (ore A) and a new case involving significant gangue entrainment (ore B). The results demonstrate that the model accurately predicts species kinetics, providing a high-fidelity, cost-effective tool to optimize mineral recovery and prevent economic losses from overgrinding in industrial processing plants. Full article

To clarify the influence of the media filling ratio on fine particle production during ceramic ball grinding of magnetite, magnetite ore from the fine grinding stage of an industrial concentrator was investigated under different feed size classes and media filling ratios through grinding kinetics experiments. The generation behavior of the fine and finest particle fractions during ceramic ball grinding was systematically analyzed. The results indicate that particle size fractions with sizes less than or equal to 0.150 mm exhibit pronounced zero-order production characteristics under different filling ratios, with cumulative yields showing a strong linear relationship with grinding time. This zero-order behavior is insensitive to variations in the media filling ratio. Conversely, the generation rate of the finest size fraction is significantly affected by the media filling ratio. For coarse feed sizes, the generation rate of the finest fraction initially increases and then decreases with increasing filling ratio, reaching a peak value of 6.23%/min at a filling ratio of 35%. When the feed falls below 1.18 mm, the generation rate of the finest fraction shows a strong positive correlation with the ceramic ball filling ratio. Furthermore, based on the functional relationship between the generation rate of the finest size fraction and the mill input power, an energy–size model for magnetite ceramic ball grinding was established, providing a quantitative description of the variation in the finest particle yield with respect to the input energy and media filling ratio. The findings provide a theoretical foundation for optimizing media filling ratios, enhancing fine grinding performance, and controlling overgrinding in industrial applications. Full article

Dandelion flowers are a valuable source of bioactive compounds with well-documented health-promoting properties. However, their high water content and delicate tissue structure make them highly perishable; therefore, appropriate preservation methods are essential to maintain their biological activity. The aim of this study was to evaluate the effects of convective drying and freeze drying, as well as drying temperature, on the drying kinetics and grinding behavior of dandelion (Taraxacum officinale Weber ex F.H. Wigg.) flowers and on the color and antioxidant properties of the resulting dried material. Convective hot-air drying was several times faster than freeze drying, and drying temperature significantly affected both the duration of the process and the properties of the dried flowers. Moreover, freeze-dried samples exhibited greater grindability and higher antioxidant activity than convectively dried flowers. In addition, powder obtained from freeze-dried dandelion flowers was lighter in color and exhibited lower redness and higher yellowness compared with samples obtained by hot-air drying. Both color coordinates and particle size after grinding were correlated with the antioxidant activity of the dried material. Full article

Grinding is an essential process in mineral processing. Hydrogen-based mineral phase transformation, used to efficiently process refractory iron ores, can alter the physical and chemical properties of the ore, affecting its grinding characteristics. This paper uses iron ore from Baoshan, Shanxi Province, as the raw material for laboratory-scale hydrogen-based mineral phase transformation (HMPT) experiments and grinding tests. It examines the impact of four cooling methods on the ore’s grinding characteristics. The results show that samples cooled in a reducing atmosphere to 200 °C and then water-quenched exhibit the best relative grindability. For the same grinding time, the content of coarse-sized particles (+0.074 mm) in the product is lowest, while the fine-sized particles (−0.030 mm) is highest. The grinding kinetic parameters of the samples with this cooling method are the highest. After 2 min of grinding, the value of n is 1.3363, and the particle size distribution of the product is the most uniform. The BET and SEM test results indicate that samples with this cooling method have more internal pores, the largest pore size, and the most surface cracks and pores. This paper clarifies the effects of the HMPT cooling methods on grinding characteristics, providing a theoretical foundation for the efficient separation of iron ores. Full article

Ceramic balls, as an emerging grinding medium, require a systematic method for optimizing their size distribution in wet ball mills. This study proposes an innovative approach that integrates Duan’s semi-theoretical ball diameter formula with breakage statistical mechanics to determine the optimal ceramic ball size distribution. The ideal ball diameters for grinding 2.36–3.0 mm, 1.18–2.36 mm, 0.60–1.18 mm, and 0.30–0.60 mm tungsten ore were identified as 55 mm, 50 mm, 35 mm, and 20 mm, respectively. Subsequently, the optimal ball size distribution was formulated as CB3: Ø55 mm:Ø50 mm:Ø35 mm:Ø20 mm = 30%:40%:20%:10%. Comparative sieve analysis and discrete element method (DEM) simulations confirmed that the CB3 distribution yields the highest proportion of qualified particles, the most favorable collision frequency, and the greatest kinetic energy among all tested configurations. The proposed method demonstrates both accuracy and practicality, providing a theoretical foundation for the industrial application of ceramic ball grinding systems. Full article

Activated carbon beads, some of which contain Fe₃O₄ nanoparticles or graphene oxide, were synthesized by thermal activation (700 °C) of chitosan hydrogel beads. Materials showed a multiporous scale (micro/meso/macro) and BET specific surface areas in the 260–572 m².g⁻¹ range. The adsorption kinetics of beads and powders resulting from their grinding were studied for a mixture of six micropollutants (bisphenol A, carbofuran, carbamazepine, diclofenac, dimethoate and imidacloprid) dissolved in spring water. While the adsorption kinetics on the beads (pH 7.3, 25 °C, 10–100 µg.L⁻¹) are slow (equilibrium time > 24 h), the powdered samples are more efficient: for an initial concentration of 50 μg.L⁻¹ of each pollutant (0.1 g.L⁻¹ of adsorbent), 50 to 99% of the micropollutants introduced into the solution were removed after 4 h of contact time. Depending on the pollutant nature, the adsorption isotherms (0.2–40 μg.L⁻¹) studied for an activated carbon powder containing Fe₃O₄ (1 mass %) are either of Langmuir or Freundlich type, or they follow Henry’s law and are related to the different properties of the molecules. Full article

Liquid effluents generated during mineral processing are usually contaminated with heavy metals and oxyanions, requiring an effective technique for their simultaneous removal. This study evaluated adsorption as a method to remove ions from an artificial acid effluent containing Cu²⁺, Zn²⁺, and ${\mathrm{S}\mathrm{O}}_4^{2-}$, using a mixture of activated carbon and barite as adsorbents. Adsorbent particles were prepared by grinding in a ring pulverizer for 120 s, using equal proportions of activated carbon and barite concentrate. The pH, contact time, and adsorbent particle mass were investigated. The results indicated that the adsorption efficiency depends on pH and adsorbent particle concentration: with increasing pH, the adsorption of Cu²⁺ and Zn²⁺ improves, while that of ${\mathrm{S}\mathrm{O}}_4^{2-}$ decreases. As the particle mass increases, the adsorption efficiency also increases. The maximum efficiency of simultaneous adsorption of ions of 55 ± 2.6% was achieved at pH 3 with an adsorbent particle concentration of 40 g·L⁻¹. The experimental data best fit the pseudo-1st-order kinetic model, suggesting that the limiting stage is external or internal diffusion and that the predominant adsorption mechanism is physisorption. Furthermore, the results were best fitted to the Freundlich isotherm, indicating heterogeneous and multilayer adsorption. In conclusion, the mixture of activated carbon and barite is presented as a potential adsorbent for acid effluent treatment with heavy metals and oxyanions. Full article

The study of the destruction mechanisms of mineral component particles during processing in grinding units is a relevant scientific problem that requires further theoretical and experimental solutions. This work is dedicated to determining the kinetic characteristics of ferromagnetic bodies moving under the influence of an electromagnetic field within a vortex mill. Dependencies of the velocity of these bodies on the radial coordinate for various values of magnetic induction and its gradient were obtained, establishing that velocities can reach approximately 50 m/s. A model for the disintegration of Portland cement particles, caused by their interaction during mechanical processing in a vortex mill, has been developed. It is shown that the average number of disintegration events for the predominant portion of the studied particles is two, which is significantly lower than the total number of collisions. An analysis of the key factors influencing the intensity and nature of particle destruction was conducted, including the magnitude of magnetic induction, the switching frequency of electromagnets, and the magnetic susceptibility of the processed materials. Based on a statistical analysis of the particle size distributions of the mineral raw material after dispersion, a principle for dividing the space within the working volume of the unit into functional zones was formulated: (1) a zone of mixing, grinding, and particle activation (at ferromagnetic element speeds of 0–12 m/s); (2) a zone of intensive grinding and particle activation (with speeds of 12–50 m/s). Full article

This study investigated the drying–grinding–extrusion processing of camel compound feeds enriched with locally available botanicals. A 2 × 2 × 3 full factorial design was applied to evaluate the effects of infrared drying temperature (two levels), grinding time (two levels), and extrusion screw speed (three levels) on process efficiency and product quality. Moisture calibration was performed using gravimetric reference values. Drying kinetics were modeled with Page and Midilli equations, while specific energy consumption (SEC) and specific moisture extraction rate (SMER) were calculated. Particle-size distribution, extrusion parameters, and extrudate properties (expansion ratio, bulk density, water absorption index (WAI), water solubility index (WSI), hardness, and color) were analyzed. Infrared drying resulted in faster moisture removal and greater energy efficiency compared with convective drying. The Midilli model provided the best fit to drying kinetics data. The results indicate that optimized combinations of drying, grinding, and extrusion conditions can enhance the technological and nutritional potential of camel compound feeds; however, biological validation is required. Limitations: These findings are limited to processing and compositional outcomes; biological validation in camels (in vivo or in vitro) remains necessary to confirm effects on digestibility, health, or performance. Full article

Using solid waste from the non-ferrous metal industry as non-traditional supplementary cementitious material has attracted increasing attention. In this study, iron-rich slag (IRS) was incorporated into calcium sulfoaluminate cement (CSC) to improve its properties, and its strength development and hydration mechanism were systematically evaluated. Three types of IRS with distinct particle size characteristics were fabricated through mechanical grinding, and their effects on the strength development and hydration heat evolution of CSC-based materials were investigated. Furthermore, several solid-phase analysis methods were employed to characterize the hydration mechanisms and microstructural characteristics of IRS-containing CSC-based materials. The results show that mechanical grinding enhances the reactivity of IRS in CSC-based systems, which in turn facilitates the generation of hydrates like ettringite (AFt), AH₃, and C–S–H gel, thereby improving their strength. The incorporation of IRS effectively decreases the total hydration heat released by CSC-based materials within 24 h. Furthermore, evidence from EDS analysis suggests the possible isomorphic substitution of Al³⁺ by Fe³⁺ in AFt, which, along with the slower reaction kinetics of Fe-AFt, may contribute to the improved late-age strength development of CSC-based materials. This study proposes a sustainable strategy for producing high-performance CSC-based materials and offers a potential approach for the high-value use of non-ferrous metal industry solid waste in construction materials, thereby demonstrating both scientific value and practical engineering significance. Full article