Separate Grains Research Articles

Precious and Base Metal Minerals in Black Sands of the Egyptian Mediterranean Coast: Mineralogical and Geochemical Attributes

This paper investigates the mineralogical and geochemical characteristics, as well as the possible sources, of gold, silver, platinum group elements (PGE), copper, and lead found in the beach sands along Egypt’s Mediterranean coast. Using scanning electron microscopy and electron probe micro-analysis, this study determines the morphology and micro-chemistry of separated grains to assess their economic potential and how various minerals respond to different transport distances. The analysis reveals that gold grains are of high purity (94.11 to 98.55 wt.%; average 96 wt.% Au) and are alloyed with Ag (1.28–2.32 wt.%) and Cu (0.16–3.15 wt.%). Two types of gold grains were identified, indicating differences in transport distances. Variations in morphology, surface features, inclusion types, rims, and chemistry of the native metals, including gold grains, suggest differences in composition, weathering degree, transport distance, deposit types, and host rocks. The average Ag concentration in gold grains (1.86 wt.%) suggests a link to mesothermal or supergene deposits. Most silver, copper, and lead grains are spherical, with some variations in shape. Silver grains have 71.66–95.34 wt.% Ag (avg. 82.67 wt.%). Copper grains have 92.54–98.42 wt.% Cu (avg. 94.22 wt.%). Lead grains contain 74.22–84.45 wt.% Pb (avg. 79.26 wt.%). The identified platinum group minerals (PGM) belong to the Pt–Fe alloys and sperrylite, both of which are PPGE-bearing minerals. These metals likely originate from the weathering of upstream Nile tributaries surrounded by igneous and metamorphic rocks from Ethiopian and Central African regions, with a minor contribution from the Egyptian Eastern Desert Mountains.

Design and Fabrication of Gravity Separator for Grains and Dust

Gravity separators are machines used to separate grains and dust by using the difference in weight between grains and dust. They work by causing grains to fall at different speeds, with heavier grains falling faster and lighter dust falling slower. The new gravity separator design is more efficient and effective than previous designs, making it easier to clean and maintain. It has the potential to revolutionize the separation process, saving businesses time and money. The new gravity separator is more effective at separating grains from dust and other impurities, improving the quality of food products and mined minerals. Additionally, it is also reducing waste.

High performance Mn/Mg co-modified calcium-based material via EDTA chelating agent for effective solar energy storage

Calcium-based material is a very promising candidate energy storage material for next generation concentrated solar power (CSP) plants with operation temperatures above 700 °C. However, performance decay and poor solar absorption capacity limit the large utilization of calcium-based material. Here, ethylene diamine tetraacetic acid (EDTA)-assisted sol–gel method is first employed to modify CaO with magnesium (Mg) and manganese (Mn) elements. MgO and Ca2MnO4 nanoparticles are attached to the surface of CaO particles to separate grains spatially to inhibit sintering. In addition to the external separation effect, Mn elements are found to be doped successfully into CaO crystal lattice rather than simply mixed, which restrains atomic diffusion and agglomeration inside CaO and thus further inhibits sintering more efficiently. The Mg and Mn co-doped sample (Ca:Mn:Mg = 9:1:2) synthesized by EDTA demonstrates exceptional thermal stability at 800 °C. The performance decay is only 6.3 % after 100 cycles and mainly manifests in the first ten cycles (4 %). Furthermore, by combining two-step calcination to avoid agglomeration and uneven doping, we also obtain the co-doped sample (Ca:Mn:Mg = 9:1:1) with nearly no performance decay in 100 cycles. The proposed materials possess an average solar absorptance of 67 %, about 4 times that of pure calcium material. This work not only designs energy storage materials with excellent performance expected to be applied in the next generation CSP plant but also provides a lattice doping route for calcium-based material modification.

Microscopic insights into poly- and mono-crystalline methane hydrate dissociation in Na-montmorillonite pores at static and dynamic fluid conditions

Knowledge on the kinetics of gas hydrate dissociation in clay pores at static and dynamic fluid conditions is a fundamental scientific issue for improving gas production efficiency from hydrate deposits using thermal stimulation and depressurization respectively. Here, molecular dynamics simulations were used to investigate poly- and mono-crystalline methane hydrates in Na-montmorillonite clay nanopores. Simulation results show that hydrate dissociation is highly sensitive to temperature and pressure gradients, but their effects differ. Temperature changes increase thermal instability of water and gas molecules, leading to layer-by-layer dissociation from the outer surface. Under flow conditions, laminar flow predominates in nano-pores, and non-Darcy flow occurs due to clay-fluid interactions. Viscous flow disrupts hydrogen bonding at the hydrate surface, enhancing kinetic instability of water. Grain boundaries of polycrystalline hydrates are less stable compared to bulk phases and preferentially decompose, forming new dissociation fronts. This accelerates dissociation compared to monocrystalline hydrates. Fracture occurs at the grain boundaries of polycrystalline hydrate in the fluid, resulting in separate hydrate crystal grains. This fracture process further accelerates hydrate dissociation. In flow systems, methane nanobubbles form in fluid and readily transport with fluid flow. Unlike surface nanobubbles at static conditions, these liquid nanobubbles exhibit mobility. The findings of this study can contribute to a better understanding of the complex phase transition behavior of hydrate in confined environment, and provide theoretical support for improving production control technology.

Natural hydrogen in low temperature geofluids in a Precambrian granite, South Australia. Implications for hydrogen generation and movement in the upper crust

Natural hydrogen (H2) has the potential to be a low-carbon fuel and energy source, playing a crucial role in achieving a clean, secure, and affordable energy future. However, our understanding of the generation, migration, and accumulation of H2 in the subsurface remains poorly constrained. Increasing evidence suggests that H2 is abundantly and widely present in various geological settings, making them viable targets for exploration of this emerging resource. Reports have indicated the presence of hydrogen-dominated natural gas in vintage boreholes located in the Yorke Peninsula and Kangaroo Island, South Australia. These boreholes were drilled in Cambrian sedimentary cover over Precambrian terranes that host iron ore, copper or gold ore deposits. To gain insight into these occurrences, rock samples were examined from the Roxby Downs granite, a Mesoproterozoic pluton associated with the Hiltaba Suite event (1.59 Ga), belonging to the same magmatic origin as the Yorke Peninsula basement.Our investigation revealed metasomatic fluid circulation, evidenced by alteration of feldspar and mafic grains, as well as discrete cemented fractures within the granite. In some of these fracture-fill cements, we discovered water and gas inclusions containing hydrogen. The formation of the hydrogen-bearing cements occurred at paleo-temperatures ranging from 170 °C to the present-day 55 °C. Analysing the oxygen isotope values of the quartz cements and considering their fluid inclusion temperatures, a marine water signature as the source of water in equilibrium with the quartz cements was identified.To constrain the fluid history, neon and argon isotope signatures from the fluid inclusion gases were measured from the granite and separated quartz grains. Nucleogenic neon isotopes increased with depth along specific production lines. While this is consistent with long-lived fluid within the granite and increasing fluid residence with depth, separated quartz grains show less variation with depth and suggest that younger fluids were introduced, triggering alteration of less robust minerals, visible in bulk granite. Petrographic analyses identified hydrolytic alterations of mafic minerals into magnetite, and subsequently magnetite to hematite, as sources of hydrogen and contributors to the observed increase in pore water salinity. Our findings highlight that natural hydrogen can be produced and retained in granites at low temperatures, expanding beyond the commonly reported alteration processes observed in mafic and ultramafic rocks.

Investigating Grain-on Malt Whiskey Production Using Naked Barley

The ability to produce malt whiskey using grain-on production methods may benefit American craft spirit producers who lack the capacity to separate grains from the wort prior to fermentation and distillation. Off-flavors thought to be derived from barley husk material have prevented distillers from producing whiskey made entirely from malt with grain-on production methods. In the present study, the impacts of using a huskless, naked barley to produce grain-on malt whiskey was investigated. New make spirit was produced at laboratory scale using malt from the covered barley variety Lightning and naked barley variety Buck. The level of esters, higher alcohols, and total polyphenols was measured in the new make spirit. Distillate made from naked barley malt (50% ABV) had a total fusel oil concentration of 2,767 mg/L while whiskey made from covered barley malt had a higher total fusel oil concentration of 3,128 mg/L. Ester levels between the two spirits were similar, with levels of ethyl acetate measuring 7.15 mg/L in the whiskey made from naked barley malt and 7.68 mg/L in the whiskey made from husked barley malt. No polyphenols were detected in either spirit. The new make spirit was also subjected to sensory analysis in the form of a triangle test and quantitative descriptive analysis. Panelists were able to detect a difference between the samples, and whiskey made from naked barley malt was perceived to have a reduction in cereal, feinty, and pungent character. Additionally, despite the naked barley being a GN producer, processing during malting reduced GN to a level associated with non-producing varieties.

Effects of the storage temperature and time of corn from the center and extremities of corncob on quality parameters

The objective was to evaluate the effects of storage temperature and storage time of corn from the center and extremities of corncob on quality parameters. Even though 60 °C is considered an indicated temperature for corn drying air when the mass presents uneven dimensions, the grains from the center are still more affected. In this case, the latent damage caused to the grains from the center of the corncob was pronounced during storage, worsening with increasing temperature and storage time. The higher acidity (1.29 mg NaOH 100g-1), lipase activity (10.51%), fermented grains (3.32%), rotten grains (0.58%), moldy grains (1.06%), and pasting temperature (91.08 °C), and by the lower soluble protein (14.56%) and non-defectives grains (94.35%) were observed in the grains from the center, separated after storage for 6 months at 25 °C. These results suggest that: a) the separation of grains from the center and extremities of the corncob during the post-harvest stages can increase the amount of non-defectives grains by more than 2% after 6 months of storage at 25 °C, and b) genetic improvement studies should be carried out to search for new genotypes with higher grain uniformity along the corncob.

Gravity and electrostatic separation of unburned coal from a selected fly ash

Unburned coal grains make it difficult to use fly ash economically, which causes energy losses in the fuel. The article presents the possibilities of separating unburned coal from selected fly ash. In order to assess the possibility of separation of unburned carbon, the analysis of grain density and ash composition was used. Unburned coal was separated by four methods – one wet gravity and three dry methods. It has been found that despite very fine ash grains, the quality and quantity of separation products are significantly dependent on the separation method used and the separated grains’ qualitative characteristics. The analysis of the coal grains under an electron microscope has revealed that they contain mineral inclusions. Their presence enables selective separation of carbon without first grinding the middling grains. The most advantageous results of the separation of unburned coal were obtained by the electrostatic separation method. Separated coal can be used in high-value carbon applications.

Improvement of the environmental safety of weaving equipment by reducing the wear of contact surfaces

The purpose of the work is improvement of the environmental safety of weaving equipment by reducing the wear of contact surfaces. For the environment, minimizing the wear during the operation of weaving equipment is of great importance. Nevertheless, the physical-chemical interaction of metal surfaces with the environment in its individual sections is uneven due to its polycrystalline structure and heterogeneity. At the same time, the value of their residual stresses (microstresses), the degree of plastic deformation, etc., have a significant effect on the physical and chemical activity of separate surface grains. The article covers the causes of wear of the batten mechanism of a shuttleless loom because of friction. In order to ensure the environmental safety of weaving equipment, methods of increasing the wear resistance of the batten mechanisms of shuttleless looms have been proposed. The article substantiates that an effective method for improving the efficiency of the batten mechanisms of shuttleless looms can be the method of surface plastic deformation of the inner surface of the batten teeth shed. As a result, the uniformity of the physical-chemical interaction of metal surfaces with the environment is ensured, as the resistance to wear and fatigue failure increases.

МИКРОСТРУКТУРЫ НА ПОВЕРХНОСТИ ЗЕРЕН КВАРЦА И ПРОИСХОЖДЕНИЕ ПАЛЕОГЕНОВЫХ ПЕСКОВ УЛЬЯНОВСКО-СЫЗРАНСКОГО ПОВОЛЖЬЯ

Quartz grains were separated by standard sieving of the Paleogene sands from the Sosnovka Formation of the Ulyanovsk-Syzran Volga region, which are a scarce and valuable raw material for glass making and construction. In order to establish the origin of the sands and restore the facies conditions of their formation, the surface microtextures of the separated quartz grains were examined by optical and electron microscopy. It was shown that the clastic grains of the Sosnovka sands bear the signs of a multi-stage formation process under the conditions of subaquatic (beach zone), eolian, mixed subaquatic-eolian (coastal dunes), injective, and continental pedological settings. For the first time, a complex of microtextures characteristic of the extrusion of grains from deep horizons under pressure and inherent in the injection mechanism of sand formation was described. The diagnostic complex of injectites includes rotational microtextures, notched microtroughs, and deformed fluid inclusions. The rather fresh appearance of the listed microtextures suggests that they were superimposed on the coastal-marine and eolian stages of the evolution with the subsequent formation of sand intrusions. At the final stage of the geological history of the Sosnovka sands, the grains were shaped by the continental pedological conditions, when secondary silica in the form of globules and their clusters cemented the quartz grains, the surface of which concatenated the features of the previous stages. Based on the results of the study, an interpretation scheme summarizing various microtextural features of the reconstructed paleoenvironments and the stages of formation the Sosnovka sands was developed. The finding that the Sosnovka sands are sand intrusions is of great practical importance, as it necessitates new approaches to the discovery and prediction of glass and quartz sand deposits confined to the Paleogene Sosnovka Formation of the Ulyanovsk-Syzran Volga region.

Nanostructured Silver Films with a Low Coefficient of Thermal Expansion as a Promising Material for Nanoelectronics

The results of a study of the thermal expansion of thin silver films obtained by thermal vacuum evaporation are presented. It is shown that, after single heating, the films consist of two types of crystallites. The nanosized fraction, for which the main area of the film is accounted, is represented by crystallites with a size of 50–60 nm. In addition to them, separate grains of hundreds of nanometers in size are observed in the samples, many of which are formed during the condensation process. The coefficient of linear thermal expansion of nanocrystalline films which is only 7 × 10−6 K−1 is determined by electron diffraction using the method of measurement standard. This is significantly lower than the value which is typical for bulk samples. The decrease in the coefficient of thermal expansion is explained by the nanocrystalline nature of the films. The closeness of the obtained value to the coefficient of thermal expansion of silicon and germanium allows us to consider the use of nanocrystalline silver films as an effective way to improve the reliability and efficiency of modern and prospective microelectronics.

Stochastic analysis of micro-cone penetration tests in snow

Abstract. Cone penetration tests have long been used to characterize snowpack stratigraphy. With the development of sophisticated digital penetrometers such as the SnowMicroPen, vertical profiles of snow hardness can now be measured at a spatial resolution of a few micrometers. By using small penetrometer tips at this high vertical resolution, further details of the penetration process are resolved, leading to many more stochastic signals. An accurate interpretation of these signals regarding snow characteristics requires advanced data analysis. Here, the failure of ice connections and the pushing aside of separated snow grains during cone penetration lead to a combination of (a) diffusive noise, as in Brownian motion, and (b) jumpy noise, as proposed by previous dedicated inversion methods. The determination of the Kramers–Moyal coefficients enables differentiating between diffusive and jumpy behaviors and determining the functional resistance dependencies of these stochastic contributions. We show how different snow types can be characterized by this combination of highly resolved measurements and data analysis methods. In particular, we show that denser snow structures exhibited a more collective diffusive behavior supposedly related to the pushing aside of separated snow grains. On less dense structures with larger pore space, the measured hardness profile appeared to be characterized by stronger jump noise, which we interpret as related to breaking of a single cohesive bond. The proposed methodology provides new insights into the characterization of the snowpack stratigraphy with micro-cone penetration tests.

Role of nickel in structural and mechanical properties of nc-WNNi sputtered nanocomposite coatings

Nanocomposites coatings offers a wide range of possibilities to promote hardness, oxidation resistance, wear resistance, etc properties significant for protective coatings. Finding new nanostructured coating with high hardness and thermal stabilities are the prime requirement of modern industries. In view of above, the nc-WNNi nanocomposite coatings were deposited using reactively sputtered method on silicon (100) substrate by varying the power of Nickel (Ni). The coatings were characterized by using grazing incidence X-ray diffraction (GIXRD), Field emission scanning electron microscope (FESEM), energy dispersive x-ray analysis (EDX), thickness profiler, four probe resistivity measurement and nanoindentation tester. Through GIXRD studies the desired face centered cubic W2N phase was confirmed, with decreasing crystallite size on increasing Ni power (content). FESEM image revels/suggest that at low Ni content, the film structure stabilized into well separated grains with the presence of grain boundary and were of uneven shape throughout. On increasing Ni power, the agglomeration increase and no clear signature of grain boundaries were visible. The resistivity of the films was found to be decreasing with increasing Ni content at different temperatures. Improved mechanical properties were observed at low Ni power (content), which drastically decreases with increasing Ni power. The highest hardness (H), elastic modulus (Er), elastic recovery (We), and resistance to plastic deformation (H3/E2) were obtained 26.60 GPa, 276.82 GPa, 69.80 GPa, 245 MPa respectively for nc-WN10Ni film. The nc-WN10Ni film shows the highest mechanical properties as compared to others.

Determining Alloy Nucleation Core Origin and Grain Refinement Strategy Based on the Dependence Degree of Content Difference

What is nucleation core origin during alloy solidification, especially for equiaxed grains? Different dependence degrees of the magnitude or occurrence of element content variation could shed light on this long-standing issue in actual large ingots. Here, based on etched surface height and grayscale, element content distributions within the solid fraction in continuous casting billets and additive manufacturing samples are first obtained by only a two-dimensional surface. Then, combined with the phylogenetic trees, the rank correlation is applied to measure the dependence of content differences during initial solidification. Assessments of external dependence degrees are helpful to determine nucleation core origin and low internal dependence degree facilitates grain refinement. Moreover, in continuous casting, some nucleation cores in the central equiaxed grain zone are confirmed to originate from the edge-chilled zone and high equiaxed grain area ratio under a low superheat, which is attributed to the low ratio of temperature gradient to growth rate rather than remelting fewer cores originating from the chilled zone. In addition, the floating behavior of separated grains originating from the chilled zone can be affected by gravity force, but these grains should be more active when increasing the casting superheat that may weaken the influence of gravity to a certain extent.

内外滚筒式荞麦脱粒机设计及田间试验

Aiming at the problems of large loss rate and high damage rate during buckwheat threshing, an inner and outer roller buckwheat thresher was designed. The device is mainly composed of an inner roller and an outer roller, the inner roller is a rod-tooth combination roller, and the outer roller is a grid roller, the inner and outer rollers can be rotated independently. The outer roller is supported on the friction wheels and the supporting wheels, and driven to rotate by the friction wheel transmission system. The compression device is installed at the top to prevent the outer roller from slipping during the rotation. During working, the materials enter between the inner and outer rollers and the separation of grains and stems under the brushing and kneading action of the inner and outer rollers takes place. In order to push the materials between the inner and outer rollers smoothly, a double spiral blade type screw feeding device was designed. By establishing a mathematical model of material pushing, the screw feeding device has a material conveying speed of 1.87 m/s and a conveying capacity of 4.29 kg/s. In order to study the threshing performance, the threshing device was installed on the basis of the Kubota 688 tracked type combine to complete a prototype of a tracked buckwheat combination harvester. Field tests show that the grain impurity rate is 6.50%, the grain damage rate is 1.42%, the threshing loss rate is 0.25%, the cleaning loss rate is 1.01%, the direct loss rate of the header is 2.43%, and the total machine harvest loss rate is 3.69% at the working speed of 0.53 m/s and the feeding rate of 0.41 kg/s. The test results provide a basis for the improvement of buckwheat mechanized harvesting machinery.

Optical borehole-wall analysis – Useful method for planetary environment reconstruction

A borehole-wall scanner was developed with 0.1 mm spatial resolution and used to analyse borehole surfaces in Earth analogue tests to support the drilling of ExoMars 2020 rover and other future missions. Altogether 13 field sites were analysed, and the results were interpreted together with laboratory measurements of optical, infrared and Raman instruments of the acquired samples. The tests show the instrument and method is useful to identify grains, structural features and their spatial distribution along the strata. A range of borehole-wall features could be identified, including separated grains (with identified size, shape, colour and albedo), aggregates, layering, deformation features, voids left behind after fallen out grains. Two basic lithological types could be identified: the heterogeneous fragile sedimentary, and the homogeneous stronger volcanic/magmatic rocks. The drilling produced artefacts such as smearing of soft material or aggregation of existing small grains could that provide information on the presence of plastic material. The experiences of borehole-wall analysis revealed that walls usually show highly heterogeneous appearance at all spatial scales – but the crushed samples were homogeneous, as structural information were lost during the sample crushing. Thus optical scanning of drilled holes provide important information that we propose should be used during sample acquisition for future lunar drilling and Mars Sample Return.

Design and Assessment of a Small-Scale Machine for Cleaning Wheat Grains

Abstract A small-scale wheat cleaning machine was designed to winnow and separate grains from materials-other-than-grains (MOG), such as premature grains and chaff, in order to enhance the quality of grains. It was evaluated technically with respect to assessment criteria: cleanliness, grain loss, chaff rejection, and cleaning efficiency. Experiments were carried out at three levels of sieve slopes (5, 10, and 15°), two sieve reciprocating speeds (0.48 and 0.95 m·s−1), two levels of feed rates (1 and 1.5 kg·min−1), and three air velocities (5, 6 and 7 m·s−1). The results showed that, at sieve reciprocating speed of 0.95 m·s−1, the maximum cleanliness value was – 96.25% – observed at 1.5 kg·min−1 feed rate, 5 m·s−1 air velocity and 5° sieve slope. The minimum cleanliness value – 76.82% – was observed at a feed rate of 1 kg·min−1, 15° sieve slope, 7 m·s−1 air velocity, and 0.48 m·s−1 sieve reciprocating speed. The results showed that the use of either a very low, or a very high sieve slope angle and sieve reciprocating speed while using different air velocities and feed rates is not recommended.

Dynamic Entropy of Two-Dimensional Active Brownian Systems in Colloidal Plasmas.

We analyze the experimental data on the motion of active Brownian micrograins in RF discharge plasmas. In the experiments, two types of microparticles were used: first—plastic grains fully covered with metal, and second—Janus particles with a thin metal cap. We have tracked the trajectories of the separate grains and plotted the pair correlation functions of the observed structures. To examine the motion of the grains, we studied the dependencies of the MFPT dynamic entropy on the coarsening parameter, the fractal dimension of the system on its mean kinetic temperature, and the mean localization area of the grain on its mean kinetic temperature. Based on the obtained results, we conclude that the character of motion of our active Brownian systems changes as the power of an illuminating laser (and, therefore, the mean kinetic temperature of the grains) increases. Janus particles change their trajectories from more chaotic to spiral-like ones; in the case of fully covered particles, we observe the dynamical phase transition from the more ordered structure to the less ordered one.

Universally characterizing atomistic strain via simulation, statistics, and machine learning: Low-angle grain boundaries

When applied to catalysis and related materials phenomena, grain boundary (GB) engineering optimizes over many currently disparately defined properties. Such properties include GB mobility, solute diffusivity, and catalytic footprints correlating current density with dislocation-induced strain. A recent universalizing framework has systematically classified low-Σ GBs in relation to analogous high-angle references, distinguishing them using footprints formed from the directional straining needed to reversibly yield bicrystals from their separated grains. Correlating the elastic work profiles derived from this thermodynamic process with matching changes in GB dislocations, strain footprints can comprehensively link formerly disparate catalytic properties and materials phenomena. This research investigates such structure-energy correlations to evaluate differences between low-angle (LAGBs) and high-angle (HAGBs) GBs, systematically delineating LAGB-HAGB transitions, explaining their origins, and connecting transitions to materials phenomena. A hierarchical statistical model, nesting GB degrees of freedom within one another, systematically detects such transitions via simplified strain footprints without failure of a single unique GB structure and material combination. A more comprehensive analysis of footprint directional components and discontinuities links transitions to catalytically relevant materials phenomena, describing thermal grooving, shear coupling, complexions, and defect migration under a single universal atomistic framework. With machine learning and spatially generalized strain footprints, this framework reconciles such phenomena via more comprehensive geometry-energy correlations.

Optimization of the cylindrical sieves for separating threshed rice mixture using EDEM

The design of the cylindrical sieve equipment used for the screening and separation of agricultural granular materials is mainly through the experimental method, which has the disadvantages of a long development cycle and high cost. To solve this problem, the discrete element method (DEM) was utilized to accurately build the particle models of threshed rice components (grains, shriveled grains, and short stalks), and simulated the separation of grains from the mixture in a cylindrical sieve. The influences of rotational speed (A), cylindrical sieve diameter (B), cylindrical sieve aperture (C), and inclinational angle (D) on screening cleaning rate, screening loss rate, and screening efficiency were investigated. Meanwhile, the optimal parameters of the cylindrical sieve were obtained using a central composite design (CCD) under response surface methodology (RSM). The results of CCD showed that the quadratic multinomial model is credible and revealed that the cylindrical sieve aperture has a significant impact on the screening characteristics. It is predicted that the optimal values for screening cleaning rate, loss rate, and efficiency were 97.84%, 0.27%, and 85.38%, respectively, while A, B, C, and D were 23.6 r/min, 297 mm, 8.7 mm, and 2°, respectively. The experimental results using a real threshed rice mixture were found to be in good agreement with the optimal simulation results. This study proved a reliable research method and provides a design reference for the cylinder sieving systems for threshed rice or separation of other bulk material. Keywords: cylindrical sieve, threshed rice mixture, discrete element method, separation, rice, optimization DOI: 10.25165/j.ijabe.20221502.5150 Citation: Yuan J B, Wang J F, Li H, Qi X D, Wang Y J, Li C. Optimization of the cylindrical sieves for separating threshed rice mixture using EDEM. Int J Agric & Biol Eng, 2022; 15(2): 236–247.