Comminution Methods Research Articles

Continuously compressing crushing towards a dry processing method, a testing for graphite ore

In this study the comminution methods of graphite bearing ore were compared by using five different crushing methods, namely a jaw crusher, a roll crusher, uniaxial compression tests, and a new type of continuously compressing crushers. These new continuously compressing crushers were available in laboratory and pilot scales. The particles in the + 1700 µm size class produced by continuously compressing crushing were coarser and rougher in texture compared to the rounded particles produced traditionally by a jaw crusher. In the size class −100 µm, most of the graphite flakes were observed independently in the products of each of these crushing methods. The liberation of ultra-coarse-grained graphite flakes in size class + 300 µm was most observed after pilot-scale continuously compressing crusher. The shape and enrichment of the graphite flakes were very similar after both laboratory and pilot scale continuously compressing crushers. In contrast, the graphite flakes produced by jaw crusher appeared as broken particles in the form of accumulation of several layered and non-independent graphite flake structures. The results of this study demonstrate that the new innovative continuously compressing crushing method enables the enrichment of coarser and cleaner graphite, which has a much higher value and wider industrial applications compared to amorphous and fine-grained graphite.

Effect of material bed compression on white fused corundum product particle shape and bulk density

Comminution of corundum is a challenging task, as it has outstanding mechanical strength and is highly abrasive and is consequently applied as a blasting and polishing agent in the abrasive industry. Thus, the selection of the best comminution methods to achieve the required dispersity properties has great importance. For this, first we must understand the effects of different type of stresses and their influence on the corundum particle fractions. Laboratory scale material bed compression experiments in a piston press were carried out to examine the effect of the pressure and material bed height on the product's particle size distribution, bulk density, and particle shape. The results showed that outstanding yield, high bulk density, and spherical particle shape can be achieved by particle bed breakage in a piston press, so the high-pressure grinding roll (HPGR) technology is a promising comminution method for corundum.

Assessment of masticatory performance in patients undergoing orthognathic surgery: A systematic review and meta-analysis.

One of the main goals of orthognathic surgery is to improve the masticatory performance in patients with maxillofacial deformities. The aim of this study was to evaluate the literature on assessing masticatory performance before, after orthognathic surgery and normal occlusion. An electronic search was performed via Pubmed, Scopus, LILACs and Web of Science without any restrictions until June 2022. The articles assessing masticatory performance using a comminution assay, bite force or occlusal contact area in patients undergoing orthognathic surgery with or without comparing controls were included. The risk of bias of the selected articles was assessed using the appropriate tools according to the study design. Of the 2507 records identified, 21 studies were included in the qualitative evaluation and 17 studies in the meta-analysis. Nine articles were cohort studies, and the other eight were before-after studies. Moderate to high risks of bias were found among the articles. Comparing the values before and after surgery, the meta-analysis revealed a significant improvement in the bite force and occlusal contact area at 1- and 2-year post-surgery. However, regardless of the assessed parameters, the masticatory performance in patients with normal occlusion was significantly greater than those in patients undergoing orthognathic surgery at all evaluated time points. Although combined surgical orthodontic treatment can improve impaired masticatory function, assessed by the comminution method, bite force and occlusal contact area, the improvement may not reach that of normal occlusion.

Chemical variability on Zingiber zerumbet (L.) Roscoe ex Sm. essential oil with respect to different comminution methods

Zingiber zerumbet (L.) Roscoe ex Sm. is an important perennial medicinal plant native to Southeast Asia. In this communication, the physicochemical differences in essential oil yield and chemical composition are investigated in relation to different comminution methods of Z. zerumbet rhizomes. The essential oils were extracted from the rhizomes using different comminution methods, namely grating (GR), chopping (CR), slicing (SR), using a mixture grinder (MR), and using a pestle mortar (PR). The essential oil of fresh rhizomes (FR) was also extracted to look for chemical variations depending on the respective comminution methods. Over thirty-three compounds were identified in the collections using GC-FID and GC-MS techniques. Zerumbone (69.66 ± 2.17 %- 73.9 ± 3.76%) was identified as the major compound in the collections followed by α-humulene (5.40 ± 1.38–14.99 ± 0.74%), humulene oxide-I (3.10 ± 0.23–3.81 ± 0.46%), humulene oxide-II (2.05 ± 0.06–2.47 ± 0.63%) and camphene (3.33 ± 0.68–3.56 ± 0.33%).

Influence of Comminution Methods and Air Exposure in the Production of Melissa officinalis Mother Tincture

Introduction: During the processing of fresh plants, prolonged exposure to the air can cause rapid oxidative changes, and this is further accelerated if they have large surface areas. These changes can ultimately lead to losses in valuable ingredients and deterioration of the final product. Consequently, in the food, cosmetics, and pharmaceutical industries, oxidation and the use of antioxidant conservatives are major considerations during processing and production. However, similar considerations are not currently made for herbal medicines. The differences in the UV-Vis spectra of several commercial herbal mother tinctures were investigated here to determine if the oxidation process occurred and should thus be considered during their production. Methods: The impact of air exposure on comminuted fresh Melissa officinalis and on the quality of the resulting mother tincture was evaluated using UV-Vis spectrophotometric analysis, antioxidant tests (potassium permanganate and FOLIN-Ciocalteu), and high-performance thin-layer chromatography. Results: A time-dependent decrease in phenolic compounds, UV absorbance, and antioxidant capacity of the Melissa officinalis mother tincture were observed. Specifically, the antioxidant capacity of ground Melissa officinalis in the resulting herbal mother tincture was reduced by 40.47% and 55.52% after 5 and 30 min of air exposure, respectively. Conclusions: The results indicate that the Melissa officinalis mother tincture is affected if its comminuted starting material is exposed to air during the manufacturing process and that this should be considered when producing fresh herbal medicine plant products in the future.

Material Bed Compression Experiments and the Examination of the Bulk Density of the Product

Comminution of white fused alumina (WFA) and white fused mullite (WFM) is a challenging task, as these materials have very high hardness and compression strength and are also very abrasive. Selection of the best comminution process for each particle size range thus has great importance. For this, first we must understand the effects of different types of stresses and comminution methods used for the comminution of WFA and WFM. In this article a comparison of particle size distribution and bulk density of different fractions and the influence of the applied pressure is carried out on the product of material bed compression and traditional single particle compression by roller crusher. Comminution experiments were carried out in a laboratory scale piston press to achieve material bed compression like in HPGR technology, and in an industrial scale roller crusher. The results showed that the products of the two comminution methods have a significant difference on particle size distribution and the fraction’s bulk density on both materials. The effective amount (<1 mm) of the fractured particles for WFA was 72% and 74% for WFM with material bed compression comminution and with single particle compression 30% for WFA and 28% for WFM. The highest growth in the bulk density compared to the roller crusher product was achieved by material bed compression by the piston press, with 12.3% on the 0.15 0.3 mm WFA fraction.

Improving the efficiency of fluidized bed comminution of limestone samples

Purpose: The aim of the research was to describe the properties and methods of using limestone for desulfurization of flue gases and to analyse the process of fluidized bed comminution and the influence of selected parameters and stand modification on quality of product of fluidized bed comminution. Design/methodology/approach: Tests of the grinding process on the fluidized bed were carried out using a modified fluid bed mill for operational variable parameters and their results were compared with the results received before modification. The modification of the test stand consisted of increasing the height of the grinding chamber, which ensured an increase in the volume of the fluidized layer where the grinding process takes place. Findings: Main parameters that determined the effects of comminution in the analyzed case were: overpressure of working air and the rotor speed of the classifier. The introduction of the modifications of the test stand ensured an increase in the volume of the fluidized layer in which the grinding process takes place. As well as a greater gravitational classification, which caused larger grains to be stopped in the grinding chamber and shift of characteristics of grain compositions towards finer grains. Research limitations/implications: It is assumed that the diameter of sorbent grains used in the fluidized bed can not exceed 6 mm. The granularity of the offered sorbents ranges from 0.1 mm to 1.2 mm. The quality of the desulfurization process depends on the overall granulation of used sorbent grains. Practical implications: Appropriately selected sorbent grains used in wet and dry flue gas desulphurisation plants ensure improved efficiency of the desulphurisation process and lower operating costs of the installation. Originality/value: Thanks to the comminution method used, a sorbent is obtained without impurities and with an increased specific surface, which can be used in fluidized bed boilers.

Preferential Oxycodone Loss of Physically Manipulated Abuse Deterrent Oxycodone HCl Extended Release Tablets Prepared for Nasal Insufflation Studies.

A method to reproducibly mill abuse deterrent oxycodone hydrochloride (HCl) extended release (ER) tablets was developed for a nasal insufflation pharmacokinetic (PK) study. Several comminution methods were explored before determining that a conical mill resulted in controlled milling of tablets to a size range equal to or below 1000μm. However, milling resulted in significant loss of oxycodone from abuse deterrent oxycodone HCl ER tablets compared to minimal oxycodone loss from oxycodone HCl immediate release (IR) tablets. Characterization of milled tablet powder showed that loss of oxycodone was not attributed to analytical procedures or oxycodone phase change during high intensity milling processes. The content uniformity of oxycodone in the milled tablet powder varied when ER and IR tablets were milled to a particle size distribution equal to or below 500μm but did not vary when particles were sized above 500 µm to equal to or below 1000μm. In addition, the initial excipient weight to drug substance weight ratio impacted the amount of oxycodone lost from the respective formulation. However, dissolution demonstrated that when oxycodone HCl ER tablets are milled, differences in excipient weight to drug substance weight ratio and particle size distribution of milled tablets did not result in significantly different release of oxycodone.

The effect of comminution on surface roughness and wettability of graphite particles and their relation with flotation

The surface property of minerals not only affect the adsorption capacity of collector, but also impact flotation performance. The effect of comminution methods on graphite particles surface property was studied in this research. The graphite particles with different rough surface were prepared by different comminution methods, and the surface property measured with atomic force microscope (AFM). The effect of surface property on flotation was studied by measuring of Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), contact angle and collector adsorption capacity. The results of the measurements of BET and SEM indicated that the surface roughness was beneficial to kerosene adsorption capacity, surface hydrophobicity and flotation performance of graphite particles. The measurements of contact angle indicated that the surface roughness had significant effect on the wettability of graphite particle. Based on the analysis of flotation performance and surface property, it can be concluded that comminution method could affect the surface roughness of graphite particles, thus affecting the adsorption capacity of kerosene and the wettability, consequently impacting the floatability of graphite particles.

Comparison of particle size and shape distribution of corundum produced by industrial ball mill and material bed compression

Comminution of corundum is a challenging task, as it has very high hardness and compression strength, and it is also a very abrasive material. Selection of the best comminution process for each particle size thus has a great importance. But for this, first we must understand the effects of different type of stresses and comminution methods used for the dry comminution of corundum. In this article the comparison of particle size and shape distribution of corundum produced by material bed compression and classic ball mill grinding is carried out. Comminution experiments were carried out in a laboratory scale piston press, to achieve material bed compression like in HPGR technology, and in a conventional industrial scale ball mill for particle-particle, particle-grinding media interaction. The results showed that the products of the two comminution methods have a significant difference both in particle size and shape distribution.

A Novel Classification Method of Zygomaticomaxillary Complex Fractures by Suture Comminution to Better Predict Clinical Outcomes

Purpose: To assess a novel technique for classifying zygomaticomaxillary complex (ZMC) fractures by its ability to predict clinical outcomes and reoperations when compared to a well-established classification method. Methods: The investigators conducted a retrospective cohort study over a 7-year period composed of patients with unilateral and bilateral fractures of the ZMC. Fractures were graded according to the Zingg method and a CT-based comminution method. Outcomes were classified into 3 groups: orbital complications, facial complications, and reoperation. Orbital complications consisted of enophthalmos and diplopia. Facial complications consisted of lagophthalmos, ectropion, ptosis, facial motor weakness, trismus, and malar depression. Other variables included demographics, mechanism of injury, and preoperative symptoms. Results: A total of 159 patients were identified producing a total of 204 ZMC fractures. The mean age was 40.2 ± 16.5 years and the most common mechanism of injury was motor vehicle accidents in 49.7% of patients. By the Zingg classification, B-type fractures were the most common in 46% of patients. The average total comminution score was 2.9 ± 2.4. Univariate analysis showed an association between increased age and reoperation ( P = .01). After adjusting for demographic and clinical variables on multivariate analysis, total comminution score was a significant predictor of facial complications and reoperation. The Zingg method did not demonstrate significance as a predictor for facial complications or reoperation. Neither classification method was predictive of orbital complications. Conclusion: The results of this study suggest that total comminution scoring is a viable method for categorizing ZMC fractures to better predict clinical outcomes.

Microstructural analysis of sausage quality

Microstructural analysis of sausage quality

Investigation of physicochemical properties and antioxidant activity of ultrafine bamboo leaf powder prepared by ball milling

The bamboo leaf ultrafine powders were obtained by ball milling. The physicochemical properties and antioxidant activity of different particle sizes of bamboo leaf ultrafine powders were studied. The results showed that the smaller the distribution of granule diameter, the lower the flowability and density, but the higher the dissolvability. When the smallest particle size, and that was when the bamboo leaf powder was obtained by ball milling 5 hr, the content of polysaccharides, proteins, total phenols, and total flavonoids were higher than other powders. According to the scanning electron microscopy (SEM), the surface of bamboo leaf powder pretreated by superfine pulverizing was rough and collapsed. In addition, the DPPH· and ABTS· scavenging ability of bamboo leaf powder increased with the decrease in the particle size. It can be concluded that the ball milling technology is conducive to increase the yield of active substance and the antioxidant activity of bamboo leaves. Practical applications The modified method of superfine comminution significantly improved the physicochemical and antioxidant activity of bamboo powder. Therefore, superfine comminution would be a nice choice for the production of ultrafine powder from bamboo leaf. In addition, the active bamboo leaf ultrafine powder can be incorporated into other food products for enhancing textural properties and promoting favorable mouth-feel because the addition of polysaccharides, proteins, total phenols, and total flavonoids from bamboo leaves is associated with certain food properties.

Effects of drying methods (hot air, microwave, and superheated steam) on physicochemical and nutritional properties of bulgur prepared from high‐amylose and waxy hull‐less barley

AbstractBackground and objectivesBulgur, an ancient and traditional food extensively consumed in Turkey and the Middle East, has been gaining popularity elsewhere as a nutritious and convenient cereal product with prolonged shelf life. The cooking, drying, and comminution methods used for bulgur production may affect the color, yield, chemical composition, nutritive quality, and physical properties of bulgur. The objectives of this study were to produce bulgur from high‐amylose and waxy hull‐less barley (Hordeum vulgare L.) varieties and to investigate the effects of different drying methods: hot air, microwave, and superheated steam on the physicochemical and nutritional properties of barley bulgur.FindingsDifferent drying methods applied in this study for the preparation of barley bulgur had significant effects on the physicochemical and nutritious properties of the final products. Bulgur products from high‐amylose barley (cv. CDC Hilose) contained lower amounts of proteins, but higher amounts of ash, arabinoxylans, resistant starch, total dietary fiber, and vitamin E than bulgur products from waxy barley (cv. CDC Marlina). However, bulgur products from CDC Marlina exhibited significantly higher solubility of β‐glucans compared with bulgur from CDC Hilose.ConclusionsOverall, the optimal quality characteristics in terms of high bulgur yield, short cooking time, low cooking losses, high β‐glucan solubility, and high retention of vitamin E were achieved for bulgur prepared from grain dried with superheated steam at 110°C. The second best results were obtained for bulgur prepared from the microwave‐dried grain. Some differences in composition and properties of bulgur prepared from waxy and high‐amylose barley were related to genetic variations and differences in starch composition. The higher content of total dietary fiber in bulgur products from CDC Hilose was partly attributed to a higher content of resistant starch formed during the processing of this high‐amylose barley.Significance and noveltyBarley has been long considered a wholesome and nutritious grain, and the results of this study clearly showed that it can be used for the preparation of bulgur, a convenient and functional food product. The use of superheated steam as a drying method for the preparation of barley bulgur proved to generate product with superior properties, especially when compared to conventional hot air drying.

Формирование микроструктурных характеристик сырокопчёной колбасы при различных способах измельчения мясного сырья

Формирование микроструктурных характеристик сырокопчёной колбасы при различных способах измельчения мясного сырья

Effect of Comminution Methods on Low-Rank Coal Bubble–Particle Attachment/Detachment: Implications for Flotation

The floatability of fine low-rank coal particles can be greatly influenced by their morphological characteristics, such as shape and surface roughness. In this study, the attachment efficiency and detachment amplitude of fine low-rank coal particles produced by various comminution methods onto/from the bubble surface were investigated using homemade bubble–particle wrap angle and bubble–particle attachment/detachment testing systems. Results showed that the length–diameter ratio of rod-milled products was smaller than that of crushed products. The wrap angle of particles obtained by the crushed method was larger than that obtained by the rod-milled method, i.e., particles with greater length–diameter ratio showed higher attachment efficiency onto the bubble surface. Meanwhile, particles with greater length–diameter ratio exhibited a larger detachment amplitude, which suggests that it is more difficult to be detached from the bubble surface. However, rod-milled products showed lower attachment onto the bubble surface. The flotation test confirmed that the floatability ratio of crushed products was higher than that of rod-milled products, consistent with evidence from experimental analyses. This study provides a fundamental understanding of particle shapes for low-rank coal flotation by a novel research method combining the attachment efficiency and detachment amplitude of bubble–particle combinations.

Metals recovery from e-scrap using gravity, electrostatic and magnetic separations

The purpose of the work was to recover metals from e-scrap, in particular from mainboards of desktop computers, using gravity, electrostatic and magnetic separation. The article describes the method of comminution as well as the yield of size fraction after this process. In addition, the separation of the fraction of 0.32 - 0.56 mm with the use of two systems: I) electrostatic and magnetic separation, and II); gravity and magnetic separation, was presented. The feed to the magnetic separator for both systems was metals (high density products). The yield of fraction 0.32 - 0.56 mm obtained after comminution was 40.7% while the yields of the products obtained from the first system were as follows: in the case of electrostatic separation, 24.9% metals and 75.1% plastics and glass; and for magnetic separation 0.7% of ferromagnetics, 19.0% of diamagnetics and 5.3% of paramagnetics. The yields of the products in the second system were: in the case of gravity separation, fraction with a density ρ > 2.96 g/cc = 33.0% and fraction with a density ρ<2.96 g/cc = 67.0%; and for magnetic separation 0.8% of ferromagnetics, 25.3% of diamagnetics and 6.9% of paramagnetics.

Влияние способа измельчения мясного сырья на стабильность цветовых характеристик сырокопченой колбасы в процессе хранения

Влияние способа измельчения мясного сырья на стабильность цветовых характеристик сырокопченой колбасы в процессе хранения

Микроструктурные и мультисенсорные характеристики сырокопченой колбасы при использовании различных способов измельчения мясного сырья

Микроструктурные и мультисенсорные характеристики сырокопченой колбасы при использовании различных способов измельчения мясного сырья

Production of Chips from Logging Residues and Their Quality for Energy: A Review of European Literature

Wood chips from logging residues are a renewable solid fuel that has become widely used in the energy sector. The current work presents a review of European papers on various aspects of wood chips production published in the years 2005–2018. The effects of the comminution method on the quality and energy parameters of the resulting wood chips were analysed. Most authors identified terrain and roadside chipping as the optimum technologies from the energy viewpoint. Furthermore, seasonal changes in the moisture content of wood chips have implications for their ash content and calorific value and determine the annual patterns of supplies to energy plants. In general, logging residues should be chipped approximately five to seven months after harvesting and delivered over economically feasible distances, which have increased in recent years due to the large dispersion of forest areas and energy plants. In a number of cases, logging residue chips did not meet the quality specifications contained in the relevant ISO standards, which may result in technological problems with their burning, especially in small to medium energy plants.