Impact Crusher Research Articles

Effect of grinding methods on slime dissociation characteristics and flotation kinetics of coking coal

Despite extensive research on the connection between coal flotation kinetics and particle size, little is known about the shape effect. To fill this gap, this study aims not only to explore dissociation characteristics and particle shape properties resulting from the grinding of coking coal in a planetary ball mill (PBM) and a vertical shaft impact crusher (VSIC) but also to investigate their effects on flotation kinetics. Moreover, for the first time in the literature, shape, kinetic rate constant, and bubble loading capacity (hydrophobicity) properties of coking coal products ground in two different mills were compared by shape characterization, flotation kinetics, and single bubble loading tests, respectively. The findings are: (1) Compared to PBM, VSIC produced rounder-shaped particles with a better communition selectivity, (2) Since PBM's flotation rate constant values (Km) were higher than VSIC's, the particles produced by the PBM exhibit a favorable aspect ratio for faster flotation.

DEM simulation of an impact crusher using the fast-cutting breakage model

The impact crusher that exploits impact rather than pressure to break down materials has been widely used in the mineral industry. To further improve its performance in material crushing, numerical simulation capable of providing a deeper insight into the complicated dynamics of feed materials than experimental study has emerged as a promising tool. However, the field of the accurate prediction of product quality and explicit simulation of breakage events inside an industrial-scale crusher remains underexplored on account of the absence of a robust breakage model and heavy computational cost. In this study, a numerical investigation of an industrial-scale crusher using the fast-cutting breakage model is conducted within the DEM (Discrete Element Method) framework. The accuracy of the breakage simulation is quantitatively validated by comparing the predicted results with the measurements from actual production. Furthermore, the influence of operating conditions including the rotation speed of the rotor and the feeding rate on the interested parameters, i.e., the power consumption of the equipment, the size distribution of the products, and the impact-induced wear is investigated comprehensively. The results illustrate that (i) the size of the product increases with the rotor speed until a critical value, after which a further increase in rotor speed will exert no significant influence on the size distribution; (ii) The feeding rate is not a critical operating condition that largely determines the fineness of the product and the efficiency of the equipment almost remain stable under a certain range of feeding rates; (iii) The wear of the devices concentrates on the rotor and the impact plates, and the distribution of the wear exhibits different characteristics in different parts, caused by the complex collision between the particles and the devices.

Laboratory and Field Performance Evaluation of NMAS 9.5, 8.0, and 5.6 mm SMA Mixtures for Sustainable Pavement

This study evaluates the laboratory and field performance of stone mastic asphalt (SMA) mixtures with nominal maximum aggregate sizes (NMAS) of 9.5, 8.0, and 5.6 mm. Aggregates and fine aggregates of these sizes were produced using an impact crusher and a polyurethane screen. Mix designs for SMA overlays on aged concrete pavement were developed. Laboratory tests assessed rutting performance using full-scale accelerated pavement testing (APT) equipment and reflective cracking resistance using an asphalt mixture performance tester (AMPT). Field evaluations included noise reduction using CPX equipment, skid resistance using SN equipment, and bond strength using field cores. Results showed that for 8.0 mm SMA mixtures to achieve the same rutting performance as 9.5 mm SMA, PG76-22 grade binder was required, whereas 5.6 mm SMA required PG82-22. The 8.0 and 5.6 mm SMA mixtures showed 22.2% and 25% reduced crack progression, respectively, compared with the 9.5 mm SMA mixtures. Field evaluations indicated that 8.0 mm and 5.6 mm SMA pavements reduced tire–pavement noise by 1.7 and 0.8 dB, increased skid resistance by 8.5% and 2.0%, and enhanced shear bond strength by 150%, compared with 9.5 mm SMA. Overall, the 8.0 mm SMA mixture on aged concrete pavement demonstrated superior durability and functionality toward sustainable pavement systems.

Employing 3D laser scanner for automated morphological assessment of aggregates produced from diverse sources and by different crushing methods

This study introduced an automated approach employing 3D scanner for quick and precise aggregates shape analysis. Recognizing existing gaps, there is still an industry demand to propose a standardized method for measuring material characteristics using 3D scanning. By addressing the limitations of previous studies, this research considered unexplored aspects of 3D scanning to improve the speed and efficiency of that. This research comprehensively examined nearly 1500 aggregates from five natural sources and five types of slag. Four statistical tests named Mann-Whitney U, Kolmogorov-Smirnov, Bootstrap, and Permutation were utilized to determine the optimal sample size for scanning. The findings suggest that scanning just 100 aggregates from each source is sufficient to be a small representative of the whole dataset and it can significantly reduce resource use while maintaining data integrity. As a practical insight, it has tried to scan a batch of 25 aggregates simultaneously in one session which could improve efficiency of scanning by reducing the processing time to just 0.6 min per particle. In MATLAB® software, some common bounding volume techniques such as Axis-Aligned, Oriented, Ellipsoid, and Sphere Bounding Box were used to analyze morphological properties. The findings showed that the aggregates sourced from Basalt, Moraine, and most of slags have more cubical shapes, while Porphyrit and Diabase aggregates are more elongated, flaky, and angular. This study also provided a comparative study of how various techniques for stone crushing affect the morphology of aggregates. The results indicate that a combination of jaw, cone, and horizontal impact crusher produces more spherical and cubical aggregates. Replacing of the cone crusher with a gyratory crusher in the same combination can improve elongation and sphericity slightly but may increase flaky particles. These insights offer valuable guidelines for future research and practical applications in construction material optimization.

The recycling potential of fibre reinforced concrete with 4D Dramix® fibres: Experimental analysis and model verification

This experimental study aims to advance sustainable construction practices by exploring the recycling potential of steel fibre reinforced concrete with 4D Dramix® fibres from the company Bekaert. In this research steel fibres from reinforced concrete specimens with varying fibre quantities of two 4D Dramix® fibre types, more precisely, the 55/50 BG and 65/50 BG fibres are recycled. A jaw crusher at the recycling company AC Materials (Flanders, Belgium) and an impact crusher at the research and development company CTP (Wallonia, Belgium) are employed to optimize the quantity and quality of the recycled fibres. Subsequently, the recycled steel fibres are reintegrated into fresh concrete mixes. The recycling process of the fibres results in a general decrease of the residual tensile strength capacity for the concrete mixtures with recycled fibres (RSFRC) compared to those with new fibres (NSFRC), and the deviation increases with increasing crack mouth opening displacement (CMOD). It was found that fibres recovered by the impact crushing process are (generally) shorter than those obtained from the jaw crusher, which results in a fibre reinforced concrete (FRC) with a somewhat lower post-cracking tensile strength. Nevertheless, most recycled fibres retain 75 % of their original capacity, considering the mean residual tensile strength of the FRC mixtures. Consequently, current findings show promising results for the recycling potential of steel fibres and the residual strength behaviour of RSFRC compared to NSFRC. Additionally, this study highlights the potential for an improved constitutive tensile model for FRC mixtures, where the design parameters ka and kc can be estimated based on the fR3k/fR1k-ratio.

Design and simulation of secondary acceleration type rotor for vertical shaft impact crusher

Design and simulation of secondary acceleration type rotor for vertical shaft impact crusher

The Crushing Distribution Morphology of a Single Particle Subjected to Rotary Impact.

In a vertical shaft impact crusher, the particle crushing process is extraordinarily complex, and the particle shape significantly influences the size distribution of the crushed product. To quantify the crushing behavior of particles more accurately and thus reveal the crushing mechanism of the crusher, an analytical approach is suggested for characterizing the crushing distribution of particles subjected to rotational impact. First, according to the working principle of vertical shaft impact crusher, a rotary impact tester was designed, and the cumulative damage model of particles under repetitive impact was established based on the theory of fracture mechanics, based on which the simulation model of single-particle rotary impact tester was constructed. Then, seven distinct particle shapes were established based on the particle shapes observed during the crusher's actual production. Finally, an investigation was conducted using the simulation model to examine the impact of various rotor velocities and particle shapes on the macroscopic mechanical properties and crushing distribution attributes of single-particle crushing. In the single-particle rotary impact crushing experiments, the findings indicated that the particle crushing transpired at the site of contact with the anvil. The particle size distribution of subparticles generated through the crushing with distinct particle shapes all exhibit single-peak characteristics as rotor speed increases. The magnitude of the peak value progressively escalates in tandem with the rotor speed increase. Furthermore, as the rotor speed increases, so do the cumulative mass distribution and the maximum continuous crushing cumulative mass. When the horizontal aspect ratio of the particles is V < 1 and V > 1, the crushing effect of the particles is poor at the same rotational speed; the curve of the maximum continuous crushing degree has an inverted "V″ shape. The crushing effect of the particles improves as their edges become progressively sharper, and the maximum continuous crushing degree of the particles increases as the edge sharpness of the particles advances.

Restoration of the Impact Crusher Rotor Using FCAW with High-Manganese Steel Reinforced by Complex Carbides

Abstract A new hardfacing alloy within the Fe-Ti-Nb-Mo-V-C alloying system was utilized to restore the working surfaces of cone crusher rotors using Flux-Cored Arc Welding (FCAW). TiC, NbC, Mo2C, VC, Mn, and ferromanganese powders were selected as the base materials for manufacturing the welding wire. The resulting hardfaced layer exhibits a composite structure, with manganese austenite as the matrix and complex solid solution reinforcements with a NaCl structure, closely resembling the formula (Ti0.3Nb0.3Mo0.3)C. The primary advantages of this hardfacing alloy include its capacity for intensive deformation hardening along with high abrasion resistance. The hardness of the hardfaced layer is approximately 47 HRC in the as-deposited state and increases to around 57 HRC after work hardening, surpassing typical hardfacing alloys derived from high manganese steel by about 10 HRC. The efficacy of the alloy was tested in restoring rotors made of Hadfield steel in a PULVOMATIC series crusher model 1145, during the milling of sand-gravel mixtures ranging from 25 to 150 mm into spalls measuring 5 to 20 mm. With an average productivity of approximately 60 tons per hour and a production volume of 300 tons, the utilization of this hardfacing alloy enabled multiple restorations of the rotor while maintaining productivity at a level of 15 thousand tons of spalls.

Effects of rock types and crushing mechanism on the 3D morphological parameters of manufactured sands: a combination study of 3D scanning and spherical harmonic analysis

This study aims to investigate the effect of rock types, i.e., granite, conglomerate rock, limestone, and crushing mechanism, i.e., Vertical Shaft Impact (VSI) crusher, Horizontal Shaft Impact (HSI) crusher, on the morphology of manufactured sands. By combining the 3D scanning and spherical harmonic analysis, the morphological parameters of manufactured sands such as elongation ratio (EL), flatness ratio (Fl), aspect ratio (AR), edge angle (EA), sphericity (SH), and fractal dimension were quantified. The results indicate limestone is more readily broken into blade-shaped particles without being able to blunt sharp edges through constant abrasion. The proportion of bladed particles in manufactured sand prepared from limestone is 1.91 times higher than the proportion of bladed particles in conglomerates. Additionally, the HSI crusher has a more significant effect on rocks with smaller strength. For the same parent rock, manufactured sand from a VSI crusher contains 30% more spherical and oblate particles than from an HSI crusher.

Influence of Recycling Processes on Properties of Fine Recycled Concrete Aggregates (FRCA): An Overview

Concrete waste recycling processes involve multiple stages, equipment, and procedures which produce Fine Recycled Concrete Aggregates (FRCA) for use in construction. This research aims at performing a comprehensive overview of the recycling technologies, recycling processes, and normative requirements to produce high-quality FRCA and to investigate the influence of these processes on their physical properties. The properties investigated were the particle size distribution (PSD), water absorption, oven-dry density, and adhered paste. The correlations between these properties were also investigated. The results indicate that the recycling processes with the highest potential for producing high-quality aggregates demand jaw crusher and impact crusher combinations. These processes are better suited for achieving FRCA with the desired particle size distribution and oven-dry density. However, water absorption and adhered paste, which are critical factors for obtaining high-quality FRCA, seem to be more dependent on the original material than on the recycling process.

Optimization of Process Parameters for a Vertical Shaft Impact Crusher through the CFD-DEM Method

Optimization of Process Parameters for a Vertical Shaft Impact Crusher through the CFD-DEM Method

Collision Energy Analysis within the Vertical Shaft Impact Crusher Based on the Computational Fluid Dynamics-Discrete Element Method.

Particles in the vertical shaft impact crusher absorb and dissipate collision energy in the impact breakage. The distribution of the collision energy determines the breakage rate of materials and breakage energy consumption of the entire system. In this paper, the gas-solid coupling method is used to explore the regional distribution of collision energy, collision frequency, and collision energy spectrum of the material particle groups. Hence, a theoretical basis is provided for the efficient and energy-saving design of the crusher. First, a coupling mathematical model of the computational fluid dynamics and discrete element method is established to describe the interaction between material and fluid in the crushing chamber. Moreover, the experiment is carried out using a PL8500 VSI crusher and compared with the simulation results to verify the model's reliability. Finally, the effects of different working conditions on the energy dissipation distribution and energy spectrum are explored. The results show that the collision energy within the crushing chamber can be accurately predicted by using the fluid-solid coupling model. Moreover, increasing the rotational speed can effectively transform low-energy collision events into high-energy collisions and increase the collision frequency with energy dissipation above the threshold energy. Thus, the probability of material breakage is increased. Last, increasing the feed rate minorly affects the material breakage rate, while the specific energy of the entire system is reduced.

Impact crusher kinematics: The dynamics of an impact swing mechanism as an analytical-mathematical model

This study presents an analytical-mathematical model that elucidates the mechanics/kinematics of an impact crusher's impact swing mechanism. Essentially, this model comprises a series of mathematical descriptions and equations that are leveraged from established mechanical principles, such as rigid body kinematics, multibody dynamics, and collision laws, thus enabling comprehensive analytical exploration of the complex mechanical-kinematical system underlying the impact swing's mechanism, particularly focusing on the system-critical activation of this mechanism when triggered by an impacting non-fragile particle. The developments presented in this paper, supportively illustrated through detailed diagrams, provide relevant insights into the operational behaviour of modern impact crushers. This research therefore not only advances the theoretical understanding of system-critical crusher kinematics but also holds significant implications for the design and optimisation of future equipment. The resulting model's ability to analytically and mathematically delineate the complex mechanical-kinematical system of an impact swing mechanism not only facilitates efficient analyses but also circumvents the extensive and resource-intensive demands typically associated with numerical simulations of such systems. Consequently, this approach thereby forms substantial added value, particularly in the realm of engineering analysis.

Optimization of the physical and mechanical processes of stone crushing by the method of computational scanning

Physical and mechanical processes for processing dry materials such as grinding and crushing are the most resource-intensive ones. It is preferable to carry out the technological process of stone crushing where maximum yield of fine-grained crushed stone with a size of 0-5 mm is obtained. The purpose of this study is to determine the optimal parameters of stone crushing on a vertical impact crusher where the yield of fine-grained crushed stone will be maximum. The physical and mechanical processes of stone crushing were optimized using the computational scanning method. The optimization was performed based on the obtained regression equation describing the output of fine-grained crushed stone from influencing factors on the process. To determine the optimal values of the factors affecting the process of stone crushing an algorithm flowchart has been developed and a calculation program has been compiled in Delphi. As a result the following values of operational factors were obtained: incoming raw material size d = 0.0375 m; the speed of the crusher rotor, n = 1600 rpm; the distance between the accelerator and the ring platform l = 0.2 m; the concentration of crushed stone size 0-5 mm at the output of the crusher will be a maximum of 55.37%.

Effect of Crushing Method on the Properties of Produced Recycled Concrete Aggregates

Construction and Demolition Waste (C&amp;DW) is generated around the world and its quantity will increase in the future. Recycling has become the favored method of dealing with concrete waste but, to avoid its downcycling, it is important to develop a recycling process which is able to produce high-grade recycled concrete aggregates (RCA). To that end, studying the influence of the production process on the properties of RCA can prove to be a crucial step toward a more circular construction industry. In this study, the influence of the crushing method is investigated. Samples of five laboratory-made concretes have been crushed using the most common mechanical crushing methods (impact crusher and jaw crusher), and the particle size distribution, morphology, hardened cement paste content and water absorption of the produced RCA have been measured and analyzed. The findings indicate that the use of impact crushers results in the production of RCA possessing more spherical geometric characteristics, albeit with a broader particle size distribution and a relatively higher content of fine particles as compared to those obtained from jaw crushers. Additionally, it is observed that the employed crushing technique seemingly exerts no discernible impact on the hardened cement paste content and the water absorption in the context of the studied concretes.

Determining parameters of grinder rotor and its blades

The rotary crusher allows you to qualitatively grind pressed roughage. The authors proposed and developed an improved technological scheme of an impact crusher equipped with two beaters for dosed transfer to the grinding chamber. The impact crusher consists of a transfer chute, metering beaters, a chopping chamber, a rotor, chopping knives, fixed knives, an exit chute, a feed bin, and an electric motor. Work efficiency is determined by the following parameters: length, width, and thickness of knives, rotor speed. The purpose of the work is to substantiate the parameters of the rotor and its knives. Analytical dependencies are obtained to determine the parameters of the knife. Theoretical studies have established that the minimum length of the knife should be 6.9 cm, the width of the knife should be 50 mm, and its thickness should be 4 mm. A model for the theoretical calculation of the probability of grinding roughage of the required size within the limits of zootechnical requirements has been obtained. Based on the calculations, the probability of cutting the feed of the required size, depending on the number of rotations of the rotors, was established.

THE RESULTS OF THE ANALYSIS OF STUDIES OF STRUCTURAL AND OPERATIONAL PARAMETERS OF IMPACT CRUSHERS FOR THE PRODUCTION OF FARM ANIMAL FEED

The article discusses the issues of improving the design and operating parameters of impact crushers for the production of farm animal feed. A special place in the diet of animals is occupied by cereals, which are characterized by a high content of protein and minerals. Improving the design and operating parameters of crushers is a difficult, but important and urgent task. As a result of the analysis, significant shortcomings of existing feed shredders were identified. Based on the analysis of the grinding process, the calculation of the speed and geometric parameters of the impact crusher was carried out. As a result of experiments with an impact crusher, the basic regression equation necessary to analyze the influence of the factors under consideration on the specific productivity of the crusher was obtained. The significance of the coefficients of the model is estimated according to the Student's criterion. The resulting model was tested for adequacy according to Fisher's theory. The model is adequate. To analyze the influence of factors on the specific characteristics of the crusher, response surfaces were constructed. When processing the results of the study using the MathCAD computer program, the maximum value of the specific productivity from the influence of all the factors under consideration was obtained, as well as their optimal values in this regression equation.

PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE FROM AQUEOUS SOLUTION USING BASE MODIFIED TERMITE SOIL UNDER UV LIGHT IRRADIATION

Photocatalysis is an effective treatment method for removal of toxic pollutants from industrial wastewaters. Sodium hydroxide was used to modified termite mound soil obtained from Ahmadu Bello University Zaria, Kaduna State, Nigeria. The soil was washed with deionized water and placed in an oven set at 60oC for 6 hrs before crushing with an aggregate impact crusher, sieved with 0.075 m mesh pore size. The sieved soil sample was tagged as unmodified-TMS (termite mound soil). The soil sample was modified using sodium hydroxide (NaOH) at different concentrations (5 %, 10 %, 15 %, and 20 % W/V). The modified and unmodified-TMS catalysts were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray fluorescence (XRF), Electron diffractive X-ray (EDX), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR), thermogravimetric analyses (TGA), and Selected area electron diffraction (SAED), The photocatalytic activity of the unmodified-TMS, 5 % NaOH, 10 % TMS-NaOH, 15 % TMS-NaOH, and 20 % TMS-NaOH, were assessed by testing the degradation rate of Methylene Blue under ultraviolet light irradiation. The results indicated that the samples exhibited the best photocatalytic activity at optimum parameters of catalyst dosage 2.5 g /L. pH 9 and 125 mg/L concentration of MB this is evidenced by the highest methylene degradation rate of (74 %). The photocatalytic degradation of the Methylene blue dye was found to obey first-order kinetics.&#x0D;

MODIFICATION OF TERMITE MOUND SOIL USING PHOSPHORIC ACID FOR PHOTODEGRADATION OF METHYLENE BLUE DYE UNDER UV LIGHT IRRADIATION

Termite mound was mined from the termite nest spotted at Ahmadu Bello University, Zaria Kaduna State, Nigeria. It was washed with deionized water and placed in an oven set at 60oC for 6 hrs before crushing with an aggregate impact crusher and sieved into 0.075 m mesh pore size. The sieved soil sample was tagged as unmodified-TMS (termite mound soil). The soil sample was modified using orthophosphoric acid (H3PO4) at different (5 %, 10 %, 15 %, and 20 %) concentrations. The modified and unmodified-TMS were characterized by the methods of scanning electronic microscope (SEM), transmission electron microscope (TEM), Electron diffractive X-ray (EDX), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR), thermogravimetric analyses (TGA), and Selected area electron diffraction (SAED), The photocatalytic activity of the unmodified-TMS, 5 % TMS-H3PO4, 10 % TMS-H3PO4 , 15 % TMS-H3PO4 , and 20 % TMS-H3PO4, were assessed by testing the degradation rate of Methylene Blue under ultraviolet light irradiation using optimum parameters (1.5 g/L, pH 11 &amp; 75 mg/L). The results indicated that the samples exhibited the best photocatalytic activity at optimum parameters of catalyst dosage 1.5 g /L. pH 11 and 75 mg/L concentration of MB as evidenced by the highest methylene degradation rate of (88 %). The photocatalytic degradation of Methylene blue dye was found to obey first-order kinetics.&#x0D;

The Physical Property Values and Suitability of Coarse Aggregates from Various Sources Used in Selected Building Construction Projects in the Kathmandu Valley

To examine the values of physical properties and suggest suitability of Coarse Aggregates from different Sources used in Selected Building Construction Projects within Kathmandu Valley. Construction of Journalism and Mass Communication Administrative Building, Construction of Central Department of Management Academic Building, Construction of Office of Registrar Building of Tribhuvan University along with Paropakar Woman and Fertility Hospital Service Extension and Research Building have been considered for study. Gradation/Sieve Analysis, Crushing Test, Abrasion Test, Impact Test on Aggregates, Shape Test Specific Gravity and Water Absorption Test and Soundness Test were done at lab. The data collected from both primary and secondary sources were summarized, classified, tabulated, categorized. For the quantitative data like various tests of coarse aggregates from different sources were tabulated, processed and a comparison was made between different physical parameters and values to standard guidelines of IS, DUDBC, NS and NS. The gradation analysis of coarse aggregates from both source lies within the limit values but the coefficient of uniformity were beyond the limit and coarse aggregates from both sources were found to be poorly graded. The LAAV parameter has no significance role in building construction related issues. The Strength, Specific Gravity, Soundness, ACV, AIV for coarse aggregates from source 2 resembles better physical properties than coarse aggregates from source 1. But, the textural parameters like FI and EI of coarse aggregates from source 1 resembles better properties than source 1but does not lie within permissible limits. This was mainly because of using cone and impact crusher for source-1 and only cone and impact crusher 2. How to cite this article: Bhatta A, Shrestha JM. The Values of Physical Properties and Suggest Suitability of Coarse Aggregates from Different Sources used in Selected Building Construction Projects within Kathmandu Valley. J Adv Res Geo Sci Rem Sens 2022; 9(3&amp;4): 26-41. DOI: https://doi.org/10.24321/2455.3190.202202