Particle Crushing Research Articles

Evaluation of CBR of Graded Crushed Stone of Flexible Base Structural Layer Based on Discrete Element Model

In order to study the mechanical properties of graded crushed stone, the discrete element method is used to simulate the CBR test of graded crushed stone. Aiming at the composition structure of graded crushed stone material, the PFC3D simulation software is used to construct the test model, and the process of constructing the virtual specimen model of the graded crushed stone discrete element model is discussed in detail. A servo mechanism is used to control the speed of the wall in the software, so as to control the virtual confining pressure imposed on graded crushed stone by the wall and simulate the real CBR test environment. The micro-parameter calibration of the virtual test is carried out by comparing the indoor and virtual CBR specimens of a single particle size specimen and three groups of graded crushed stone specimens. The comparison result shows that the stress-strain characteristics of the graded crushed rock obtained by the discrete element simulation during the uniaxial penetration process have a high degree of similarity, which can verify the accuracy of the model establishment. With the increase in the penetration depth, the penetration force of the aggregates of various particle sizes gradually increases, and the penetration force and the penetration depth are basically linear, and when the particle size is greater than 9.5 mm, the increase in particle size has little effect on the CBR test results. Under the certain conditions, the contact stiffness of graded crushed stone particles with particle sizes of 4.75 mm, 9.5 mm, 13.2 mm, 16 mm, and 19 mm should be 0.88 × 107 (N/m), 0.98 × 107 (N/m), 1.10 × 107 (N/m), 1.25 × 107 (N/m), and 2.05 × 107 (N/m), respectively. The recommended value of the contact stiffness of the small spherical particles increases with the increase in the particle size. This model can provide a basis for studying the micromechanical state of graded crushed stone and physical mechanics tests.

On Application of Internal Heat Sink Sources when Producing Castings from Wear-Resistant Chromium Cast Iron

The features of the formation of castings from chromium cast iron during casting in a combined mold are studied using internal sources of heat removal introduced into the melt. A series of experiemеnts has been carried out with wear-resistant chromium cast iron. The following macrocoolers have been used: a 0.5 mm thick silumin plate containing 3–5 % Ti; a mixture of borax and crushed ferrochrome (1–4 mm); white cast iron shot. The phase composition of the samples has been determined by X-ray diffraction analysis, and their microstructure has been also studied. Hardness testing has been carried out on specimens obtained with cast iron shot. The most effective method of using an internal source of heat removal, which has a significant effect on the cooling rate of the casting and its microstructure, has been determined. The most promising was a mixture of borax and crushed ferrochrome particles, which did not dissolve in the melt and formed zones with local structure refinement, as well as white cast iron shot, a more technological alternative to ferrochrome. The use of white cast iron shot has led to a refinement of the structure of the part “Backing sheet У3.1,1 [U3.1.1]” made of wear-resistant chromium cast iron, as well as to an increase in the hardness of its working surface by 2.6 HRC. Almost all of the shot introduced into the melt has been melted. As a result of the research, it has been revealed that the use of ferrochrome and white cast iron shot is an effective way of local structure refinement and a practical possibility of obtaining a part made of chromium cast iron with increased hardness. All this can increase the wear resistance of parts of crushing and grinding equipment.

The effect of polystyrene foam in different doses on the blood parameters and relative mass of internal organs of white mice

Due to their durability, versatility and economy, plastic products are widely used in all spheres of human life. Despite the inertness of polymers, recent studies show the ability of microplastic to overcome natural tissue barriers, accumulate in the animal’s body, affect metabolism and change the intestinal microbiota, negatively affecting it. In a 42-day experiment, changes in the internal organs’ relative mass, blood biochemical and morphological parameters of white mice were established under the influence of different doses of polystyrene foam in their diet. Four groups of white mice consumed crushed polystyrene foam particles (10%, 1% and 0.1% by weight of the feed, control group without the addition of polystyrene foam). At the end of the experiment, the morphofunctional state of the internal organs was determined by the organ mass index and blood biochemical parameters. Adding crushed polystyrene foam to the feed in an amount of 1% causes a significant decrease in the mass index of the heart and stomach, 10% – only the heart, and 0.1% – does not affect this indicator. Polystyrene foam had a significant effect on blood biochemical parameters, regardless of the dose, causing an increase in the activity of aspartate aminotransferase against the background of a decrease in the activity of alkaline phosphatase. The content of total bilirubin, urea, urea nitrogen and cholesterol decreased, and the concentration of creatinine and total protein increased (due to the albumin fraction). The use of crushed polystyrene foam in mice did not cause significant changes in the blood morphological composition, except for a dose-dependent increase in the number of monocytes. In the future, it is planned to determine histological, histochemical and immunohistochemical changes in the organs of laboratory animals under the influence of plastic in a laboratory experiment.

Experimental Study on Nonuniform Compaction and Re-Crushing Behavior for Crushed Coal Gangue Under Axial Loading

The crushed coal gangue particles are widely used in solid backfilling. However, the nonuniform compaction and internal re-crushing behavior of crushed coal gangue under bearing stress have not yet been revealed in current research. But this is particularly significant for improving the filling effect and quality. In this article, with the aid of the innovative compaction-acoustic emission (AE) test approach, the internal re-crushing properties of crushed coal gangue were studied. The main findings are listed; 1) the variation of AE parameters versus time is highly consistent with three stages of axial compression deformation; 2) the AE location and variation of AE intensity show that there are nonuniform compaction and layered re-crushing phenomenon in the compaction process of crushed coal gangue. The particle re-crushing transfers from the middle layer to the upper and lower layers; and 3) the particles screening results of the final compaction state show that the original particle size of the upper, middle, and lower layers account for 62%, 66%, and 76%, respectively, confirming the existence of layered crushing. The layered re-crushing characteristics of granular filling materials are revealed for the first time in this article.

A laboratory investigation on the effect of crushability on the interface parameters of Hormoz carbonated soil

Carbonated sands, also referred to as calcareous sediments, are a common type of soil in marine environments such as the West Australia Continental Platform, South China Sea, Persian Gulf and Oman sea and many parts of the world. During pile driving in such soils, imposed shear and volumetric strain to particles, crushing occurs which leads to change in the particle size distribution as well as interface properties of the soil-pile system. In this study, two types of sands (siliceous Firoozkooh-161 and carbonate Hormoz sand) and three types of materials (steel, wood and concrete) have been selected and were investigated using a direct shear and a tall oedometer apparatus for the prediction of the sand-pile interaction properties considering particle crushing. The smoothness and roughness of materials as well as soil relative density, and shearing rate on the interface properties were examined. Based on the results, smooth steel, wood at the direction of vessels, rough steel, smooth concrete, wood at the right angle to vessels, and rough concrete represent the lowest to the highest interface shear strength, respectively. Results revealed, increasing soil relative density leads to an increase in the interface friction angle. The results also emphasized that increasing the vertical stress leads to increasing in the breakage index both dense and loose states, however, the amount of particle increases with density. Particle crushing also decreases significantly when soil interact with smooth surfaces. Furthermore, increasing the shearing rate enhances the shear strength and reduces particle crushing. It also investigated that Hormoz sand compared to Firoozkooh sand exhibits a higher level of particle breakage due to the shape and texture of carbonated particles. Finally based on the achievements of this research, the limit values for skin friction bearing capacity of piles driven in carbonate and siliceous sands proposed in ARGEMA and API approach were examined.

Influence of the Aggregate Shape and Resistance to Fragmentation on Unbound Base Layer Resilient Modulus

The performance of unbound base materials, exclusively of the upper base layers, besides compaction level and layer thickness, depends on unbound material type, aggregates shape, fine content and mechanical properties of aggregates. The response of the pavement structure to loading is expressed through stress and strain magnitudes, accumulation of which leads to layer permanent deformations. One of the key factors for designing unbound base layers is resilient modulus, which can be found from triaxial tests. The aim of the research is to analyse the effect of the aggregate particle shape, structure and the resistance to crushing properties on resilient modulus of the upper layers of the unbound base layers. The following properties have been determined during the tests: aggregate particle size distribution, particle shape and flakiness, percentage of crushed and broken particle surfaces, density, water absorption, resilient modulus under low stress level loading. According to the performed research with tested aggregate mixtures, it is assumed that most influence on resilient modulus is exerted by aggregate whole granular size distribution, water absorption and the largest aggregate particle surface angularity. Resilient modulus in the tested dolomite fraction mixtures differing from 32 mm to 56 mm showed any reasonable difference with mean nominal pressures being higher than 300 kPa.

Three-dimensional network of nitrogen-doped carbon matrix-encapsulated Si nanoparticles/carbon nanofibers hybrids for lithium-ion battery anodes with excellent capability.

Three-dimensionally structured silicon (Si)–carbon (C) nanocomposites have great potential as anodes in lithium-ion batteries (LIBs). Here, we report a Nitrogen-doped graphene/carbon-encapsulated Si nanoparticle/carbon nanofiber composite (NG/C@Si/CNF) prepared by methods of surface modification, electrostatic self-assembly, cross-linking with heat treatment, and further carbonization as a potential high-performance anode for LIBs. The N-doped C matrix wrapped around Si nanoparticles improved the electrical conductivity of the composites and buffered the volume change of Si nanoparticles during lithiation/delithiation. Uniformly dispersed CNF in composites acted as conductive networks for the fast transport of ions and electrons. The entire tightly connected organic material of NG/C@Si and CNF prevented the crushing and shedding of particles and maintained the integrity of the electrode structure. The NG/C@Si/CNF composite exhibited better rate capability and cycling performance compared with the other electrode materials. After 100 cycles, the electrode maintained a high reversible specific capacity of 1371.4 mAh/g.

Experimental and DEM-Based Numerical Studies on the Shearing Characteristics of Talus-like Rock Mass.

The talus-like rock mass is a special kind of geomaterial widely distributed in southwestern China, which has induced serious engineering disasters for tunneling engineering. However, the mechanical behavior of the talus-like rock mass remains unclear as the previous studies mainly focused on similar geomaterials such as the soil–rock mixtures. In this paper, we have carried out both experimental and discrete element method (DEM)-based numerical analyses to investigate the shearing characteristics of the talus-like rock mass collected from a real project site. Large-scale direct shear tests reveal that the strength parameters increase with the block content, which is different from the traditional soil–rock mixture. A dependence has been discovered in that the specimen dilation becomes more obvious under lower normal stress and larger block content. It is also observed that higher normal stress is beneficial for crushing blocks. The force chains obtained in the DEM simulations show that distinct internal structures are generated in the rock samples with different block contents. The distribution of coordination number establishes the dependence of fabric stability on block content during shearing. Bond-break evolution reveals the tendencies of crushed particles were consistent with those of experimental tests. The findings provide a more in-depth understanding about the mechanical behavior of the talus-like rock mass, which helps to uncover the cause of the collapse of the real tunnel project.

Experimental measurement of particle crushing around model piles jacked in a calibration chamber

During installation of driven or jacked piles in sand, particle crushing occurs in a region below the base of these piles. Quantification of the degree and extent of particle crushing during driving or jacking in sand is necessary to improve current design methods. To study the effects of particle crushing on the capacity of piles jacked in uniform silica sand samples, a model pile was jacked and tested in a half-cylindrical calibration chamber with transparent observation windows in its front wall. Annular samples of crushed sand 3 mm in thickness were recovered after testing from several locations along the shaft and the base of the model piles and used to assess particle gradation changes and to calculate breakage parameters. Relationships between the load mobilized at the base of the model piles and three breakage parameters are proposed. Furthermore, the number of jacking strokes (ranging from 1 to 32 in this research) has a negligible effect on the degree of crushing produced during installation and on the measured stresses at the base of the model pile. Analyses of the digital images captured during pile jacking indicate that the silica sand particles in the path of the model pile crush mainly along irregularities and sharp edges. Different zones are identified below the model pile according to the degree of particle crushing. Digital images taken during static loading of the model pile allowed tracking of the displacement paths of individual sand particles during loading.

Image-Aided Analysis of Ballast Particle Movement Along a High-Speed Railway

As a core infrastructure of high-speed railways, ballast layers constituted by graded crushed stones feature noteworthy particle movement compared with normal railways, which may cause excessive settlement and have detrimental effects on train operation. However, the movement behavior remains ambiguous due to a lack of effective measurement approaches and analytical methods. In this study, an image-aided technique was developed in a full-scale model test using digital cameras and a color-based identification approach. A total of 1274 surface ballast particles were manually dyed by discernible colors to serve as tracers in the test. The movements of the surface ballast particles were tracked using the varied pixels displaying tracers in the photos that were intermittently taken during the test in the perpendicular direction. The movement behavior of ballast particles under different combinations of train speeds and axle loads was quantitatively evaluated. The obtained results indicated that the surface ballast particle movements were slight, mainly concentrated near sleepers under low-speed train loads and greatly amplified and extended to the whole surface when the train speed reached 360 km·h−1. Additionally, the development of ballast particle displacement statistically resembled its rotation. Track vibration contributed to the movements of ballast particles, which specifically were driven by vertical acceleration near the track center and horizontal acceleration at the track edge. Furthermore, the development trends of ballast particle movements and track settlement under long-term train loading were similar, and both stabilized at nearly the same time. The track performance, including the vibration characteristics, accumulated settlement, and sleeper support stiffness, was determined to be closely related to the direction and distribution of ballast particle flow, which partly deteriorated under high-speed train loads.

Potential Short-Term Effects of Mine Tailings on Phytoplankton Assemblages in the Open Ocean

The disposal of mine tailings into the marine environment is considered an essential option to secure the economic efficiency of deep-sea mining, but it might adversely affects the ecosystem. To examine the potential impacts of tailing disposal from polymetallic nodules and polymetallic sulfide mines on phytoplankton communities, addition experiments of crushed fine particles into surface seawater were conducted in the open Indian Ocean and changes in chlorophyll a fluorescence and community composition were analyzed. The addition of tailings had serious adverse effects on phytoplankton fluorescence and photosynthetic activity, regardless of mine type. The adverse effects seemed to mainly be due to the physical properties of the mine tailings. These also showed discriminatory effects on phytoplankton, resulting in great changes in community composition. The results suggest that mine tailings could have significant adverse impacts on phytoplankton assemblages, but the degree of impact greatly varies depending on the phytoplankton groups. The discriminatory impacts would cause changes in biomass, community structure, and thus ecological function.

An Experimental Investigation of the Mechanical Behavior and Particle Crushing Characteristic of Volcanic Soil.

Volcanic soil is a special soil that is well-known for its distinctive texture, vesicular nature, and particle fragility. The fragility characteristic of volcanic soil is the main factor affecting the foundation stability in road engineering. This study focuses on the mechanical properties and particle crushing characteristics of volcanic soil retrieved from Northeast China. A series of triaxial consolidation and drainage shear tests are performed on volcanic coarse-grained soil (5 mm > d > 0.075 mm) under different initial relative densities and effective confining pressures. Results show the peak friction angle of volcanic soil significantly decreases with the increase of confining pressure. The particle crushing degree of volcanic soil increases with the increase of confining pressure, particle size, and relative density. The relative breakage rate of the same particle size group has a good linear relationship with a fractal dimension. Moreover, for the same particle size, the relationship between plastic work and relative breakage rate can be fitted by a power function, which is not significantly affected by relative density or effective confining pressure. From an engineering view, in addition to increasing the compaction degree of volcanic soil, volcanic soil with fine particles used as a roadbed filler can significantly reduce the deformation of the roadbed and improve the bearing capacity of the foundation.

Experimental study on laser assisted ultrasonic elliptical vibration turning (LA-UEVT) of 70% SiCp/Al composites

SiCp/Al composites are more and more used in aerospace, military industry and other industries. However, the surface integrity of materials is poor, and the cutting force is large as the anisotropy of materials in the traditional machining (TM) process, which hinders the application of ceramic particle reinforced metal matrix composites. With the requirement of high dimensional accuracy, high efficiency and low damage for materials in these fields, non-traditional machining technology has become a research hotspot. Laser assisted machining (LAM) is a non-contact special machining method. Its advantages in machining SiCp/Al composites have been proved by experiments, but there are still processing defects such as thermal cracks. Therefore, to further improve the machining quality of 70% SiCp/Al composites with high volume fraction, a new machining method combining ultrasonic elliptical vibration turning (UEVT) and laser heating assisted turning (LAT) is proposed. High frequency intermittent machining and the adjustment of laser temperature influence on materials can be realized by adjusting the ultrasonic amplitude. Combining the characteristics of the two processing techniques, the feasibility study of the new machining method was studied by turning experiments. In this paper, compared with TM and LAT, the removal mechanism of materials and the effects of different laser heating temperatures and ultrasonic vibration on cutting force, surface quality, subsurface damage and chip morphology are explored. The results show that LA-UEVT can effectively reduce the cutting force and surface roughness, improve the plastic removal ability, and inhibit surface and subsurface damage. And the material removal process is mainly in the form of small particle crushing and particle pressing, which improves the stability of cutting force in the cutting process.

Исследование стойкости поверхности спутников к эрозийному износу

The purpose of the research was to study the high-speed impact interaction of a stream of meteor particles and the space satellite surface. The paper describes the effects arising from the movement of microparticles in a material, gives models of the solid particle–metal surfaces interaction, and introduces experimental and analytical dependencies. Within the study, we identified the main factors and estimated their influence on the wear of the surface parts. Furthermore, we examined the mechanism of material destruction depending on the ratio between the hardness of the wear particles and the material. The paper describes various ways of protecting satellites from the influence of the space environment: the use of high-strength and high friction resistance materials, e.g. tungsten, titanium, in the manufacture of the load-bearing structure; the limitation of the spacecraft operation time in space; the use of protective screens and multilayer walls. We studied friction and erosion caused by single particles, the possibility of thermally localized deformation, i.e. adiabatic shear, resulted from local heating, and introduced the mechanism of plastic materials erosion caused by small size abrasive particles. The response of the material at such particle velocities is little known. The study postulates that the material removal (wear) when the surface of the spacecraft is exposed to a stream of abrasive particles results from the interaction of several simultaneously occurring processes due to the separate or combined influence of the components of the stream of these particles. It is recommended that when considering the erosion of material in the stream around the space environment, it is necessary to take the following into account: collisions of particles with each other inside the oncoming stream; crushing of individual particles; screening of the treated surface by particles bouncing off it; a wide range of angles of incidence of particles at a certain point in time; influence of the treated surface on the trajectory of cosmic particles; subsurface damage to the material due to repeated impacts with microparticles; adsorption effect of reducing the strength of the spacecraft surface material at the interface between the spacecraft surface and the stream, etc.

Geological and engineering appraisal of hydraulic frac sand in some Egyptian localities as a proppant of oil well drilling

Sand that comprises high purity silica grains, in large percent, is of the best naturally occurring grains that can be used as proppants during hydraulic fracturing processes. Proppants are used to increase formations' permeability; to increase reservoirs' productivity, or to reopen plays and utilize unconventional reservoirs. The potentiality of these grains to be used as frac proppants is determined according to certain physical, mechanical, petrographical and chemical evaluations that include particle size analysis, acid solubility, turbidity, bulk density, crush resistance and hardness, sphericity and roundness, mineral and chemical composition. This study shows the evaluation of the silica sand samples collected from Malha Formation in Wadi El Dakhal, Eastern Desert; Naqus Formation in Wadi Qena, Eastern Desert; and Bahariya Formation at Gabal El-Dist area in Bahariya Oasis, Western Desert, Egypt. The samples were examined according to frac sand international standards. The results showed the potentiality of the tested samples to be utilized as frac sand proppants. Wadi El-Dakhal and Wadi Qena studied areas possess very promising samples for frac sand production. But, the quality of Wadi El-Dakhal samples is somewhat better than that of Wadi Qena samples. The samples of Gabal El-Dist in Bahariya Oasis are relatively less to achieve the requirements; however, they can be utilized in shallow depths.The assessment testing of the studied samples revealed a good results and verifying the standard requirements, where SiO2 content is 89.1% in Wadi Qena, 99.3 % in Wadi Dakhal and 78.1% in Gebel El Dist, crush resistance at 5000 psi gives fine percent 4.71 W.Q, 6.78 W.D, and 14.11 B.O, turbidity readings raining from 100.5 to 133.25 NTU, the grain roundness are rounded to sub rounded, and grain size distribution range is 30/50 to 40/70 grading (710 um to 210 um).

New soil abrasion testing method for evaluating the influence of geological parameters of abrasive sandy ground on scraper wear in TBM tunneling

When shield TBM tunneling in abrasive sandy ground, scrapers are loaded with heavy forces resulting from the extrusion and friction processes of sand particles. Scraper wear reflected as displacement or desquamation is related to soil parameters. Due to the lack of reliable test methods, experimental studies on the influence of soil parameters on scraper wear are limited. In the present study, existing soil abrasion testers have been reviewed to discuss the advantages and deficiencies. An improved WHU-SAT soil abrasion tester has been developed to study the influence mechanism of soil parameters on scraper wear. Experimental studies have been conducted to evaluate the variation of scraper wear with quartz content, particle size, particle shape and water content. Two soil abrasion tests have been performed for each case. Scraper wear has been considered to be the average value. The results indicate that scraper wear increases with the increase of quartz content and the growth rate increases. It is related to the particle crushing and adhesion effect of limestone sand. As the average particle size increases, the extrusion and friction between the modeled scraper and the sand particles increases first and then decreases. Thus, scraper wear increases first and then decreases with the increase of average particle size. The trend is generally comparable to the corresponding changes in scraper wear with water content. As quartz balls collide with sand particles and destroy the microscopic friction system composed of scrapers and asperities, scraper wear decreases as the increase of roundness and the falling rate decreases. Optimized solutions such as soil abrasivity evaluation, tunnel alignment optimization and soil discharge improvement have been proposed to alleviate the influence of soil parameters on scraper wear. The present study promotes the rational estimation of sand abrasivity and scraper consumption during the feasibility study of abrasive sandy gournd tunneling using shield TBM.

Vibration and tribological properties of epoxy-granite composites used as novel foundations for machine elements

Abstract Composites have become attractive to many industries today and are a good alternative to many traditional materials. Epoxy granite (EG) is used as a competitive alternative to ground ceramics, especially as a foundation for machine tools. This is because of their high damping ratio compared to other traditional materials such as cast iron. In the present study, a lightweight and cost-effective EG composite material was developed as a new foundation for machine elements. The composite material EG was prepared by mixing epoxy resin (12 wt %) and granite particles by casting method. The crushed granite particles were sieved and separated into coarse particles ≤2.36 ≥ 1.18 mm, medium particles ≤1.18 ≥ 0.6 and fine particles ≤0.6 mm. Vibration modal analysis is performed using an impact hammer to measure the natural frequencies occurring at each material size and the damping ratios. Microbial and fungal resistance is tested to understand applicability in humid environments, and water absorption and soak resistance were also measured. Scratch tests are performed using a top scratch tester to measure scratch width for fine and coarse samples. The electrostatic discharges generated by friction on the rubber and granite-epoxy composite sole are measured. It was found that as the particle size decreases, the damping ratio increases and the damping capability is improved, both microbial and fungal resistance increases, the scratch width is small for fine particles, while it is difficult to achieve for other granite sizes. Electrostatic discharges show a better feel for the composite material, but it is better with fine particles.

High-frequency acoustic cavitation in the technology of producing milk and dairy products

The article tells us about the issue of the influence of high-frequency acoustic cavitation on the quality characteristics of raw milk and white cheese produced with its use. It is shown that with the duration of milk processing for 30 minutes and the impact power of 45 kHz, the number of bacteria of the Escherichia coli group decreases by 40% and native calcium is preserved, which is subsequently necessary for the formation of a high-quality cheese layer. The effect of high-frequency acoustic cavitation on the components of milk, such as fat and protein, has been studied. It is established that during the initial period of exposure to high-frequency cavitation, there is a crushing of fat particles - homogenization with subsequent agglomeration, and then the release of free (destabilized) fat. It is worth noting that acoustic cavitation does not have a negative effect on the protein component of milk. Thus, whey proteins, which are most susceptible to denaturation (precipitation) during heat treatment, remain in the native state during cavitation exposure. The authors concluded that high-frequency acoustic exposure is technologically feasible in the production of high-protein products, in particular, in the production of white cheese. The results of histological analysis indicate that calcium in this type of processing in cheese has a structured appearance and larger associations in size compared to cheese obtained from unprocessed milk, which has a positive effect on the quality of the protein matrix of the product.

Development of a method for efficient extraction of food raw materials

Optimization of extracting food products from plant raw materials using a mathematical model is suggested. The model has been derived for the analysis of extracting pectin from Jerusalem artichoke. Multistage anti-cyclic extraction, non-stationary diffusion for the initial element of the processed raw material in the form of plates is considered. The calculations take into account the effect of reverse solvent change, the time of the solvent drain from the solid phase, among other process parameters. The derived equation makes it possible to analyze the effect of the impregnation of a part of the miscella at an intermediate stage of a countercurrent multistage extraction on the efficiency of the process. The correctness of the mass conductivity coefficient calculations was confirmed using the performance indicators of the extractor. Based on the data obtained, a mathematical model was created that describes the extraction process with a variable coefficient of mass conductivity. Thus, it is possible to determine the optimal parameters of the process including the rate of fluid flow through the material, the crushed material particle size, the thickness of the particles, and the processing time.

Mechanical Behavior and Particle Crushing of Carbonate Sand in Simple Shear Tests

Mechanical Behavior and Particle Crushing of Carbonate Sand in Simple Shear Tests