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Wyszukujesz frazę "particle breakage" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
First-order and second-order breakage rate of coarse particles in ball mill grinding
Autorzy:
Barani, K.
Balochi, H.
Powiązania:
https://bibliotekanauki.pl/articles/109734.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ball mill
grinding kinetic
particle breakage
Opis:
It has been observed by many authors that the breakage rates of coarse particles in a ball mill slow down with increasing grinding time and deviate from the first order. In this paper it is intended to find out whether the breakage rates of coarse particles obey second-order kinetics or not. For this purpose, quartz, limestone, iron ore and a mixture of quartz/limestone (weight ratio of 1:1) were selected as a ball mill feed. The first-order breakage rate was determined for the four particle sizes of quartz, limestone, iron ore and the mixture of quartz/limestone. Results indicating good first-order kinetics were obtained with the fine-sized particles (-1.2+1 mm, -0.6+0.42 mm). However, the coarse-sized particles (-5+4 mm, -3.15+2.5 mm) showed deviations from the first order. These coarse particles were in the abnormal breakage region. The second-order breakage rate was determined for the coarse particles (-5+4 mm, -3.15+2.5 mm). It can be seen that, for both sizes and all the materials, the second-order plot had better fit than the first-order plot. Also, it can be concluded that the second-order kinetics could model the breakage of coarse particles better than the first-order kinetics, and the validity of the second-order breakage rate was increased with increasing particle size. However, it is suggested to examine the validity of the second-order breakage rate kinetics for other materials and particle sizes.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 268-278
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental research on the strength distribution of brittle spheres under compression
Autorzy:
Zhou, Qiang
Guo, Qing
Pan, Yongtai
Zhu, Changyong
Wei, Yinghua
Powiązania:
https://bibliotekanauki.pl/articles/1447969.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
particle strength
breakage energy
crushing force
lognormal function
breakage probability
Opis:
The strength of a particle is one of the most crucial characteristics within a comminution process due to the mechanical stresses experienced by each particle. In this study, the K9 glass spheres and ceramic spheres were subjected to a breakage test. The test includes the breakage of up to 240 particles under compression to obtain the distribution of the breakage probability depending on the crushing force and breakage energy. The breakage test was conducted for five particle size fractions from each individual material. Thus obtained 10 crushing force distributions and corresponding 10 breakage energy distributions were fitted with lognormal distribution function. The parameters in the lognormal were analyzed including the effect of the material and particle size. Following this, the relationship between the crushing force and breakage energy was analyzed based on the Hertzian elastic contacts model and Tomas’s elastic-plastic contact model, respectively. Additionally, particle strength in terms of crushing force and breakage energy were compared and found to be size dependent. Finally, a simple transformation algorithm of distributions is developed. According to this algorithm the crushing force distribution can be transformed into breakage energy distribution and vice versa. The findings facilitate a better understanding of the particle strength distribution under compression and will help to improve the comminution process design, control and optimization.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 2; 58-69
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of energies on the impact breakage characteristic of magnetite ores
Autorzy:
Si, Liang
Cao, Yijun
Li, Guosheng
Powiązania:
https://bibliotekanauki.pl/articles/2200336.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fractal dimension
ore breakage characteristic
particle size distribution
mineral liberation
fracture morphology
Opis:
The energy applied during breakage is the key to enhancing the magnetite liberation degree and improving quality. The relationship between energy and liberation properties remains unclear due to various complicated factors affecting mineral liberation. Therefore, this work aims to study the effect of energy on the breakage characteristics of magnetite ores; the impact breakage test was conducted on magnetite particle groups at different energies using a drop weight impact tester; the statistical analysis was performed based on the fractal theory to research the particle size distribution; the fracture morphology and liberation properties of these ores were analyzed using scanning electron microscope and mineral liberation analyzer. Results show that the particle size distribution of magnetite after breakage conforms to the fractal law. The larger the energy, the greater the fractal dimension for this distribution, showing a linear relation between them, which implies that the fractal dimension can evaluate the breakage degree. The fracture morphology of magnetite ores indicates that as the energy increases, the intergranular fracture evolves into transgranular fracture, proving the influence of energy on fracture modes. It is found that the magnetite liberation degree first increases and then decreases with the rising of energy, indicating that the magnetite liberation can be improved at an appropriate amount of energy. The above conclusions provide a theoretical reference for optimizing energy and improving broken product quality.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 159098
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental research on energy-size distribution model of coal particle bed comminution
Autorzy:
Zhou, Qiang
Guo, Qing
Pan, Yongtai
Zhu, Changyong
Wei, Yinghua
Powiązania:
https://bibliotekanauki.pl/articles/1845226.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal
particle bed comminution
extended G-S distribution
JK size-dependent breakage model
mathematical modelling
Opis:
In order to accurately predict the particle size distribution (PSD) of coal particle bed comminution under different applied pressures, the tests of two kinds of coal with four size fractions under five different applied pressures were carried out by TAW-3000 hydraulic servo testing machine. The Gaudin-Schumann(G-S) distribution is extended by the fractal theory and the JK size-dependent breakage model is discussed. Two mathematical models for predicting PSD of crushing products in coal particle bed comminution are proposed. Results show that the relationship between the mass-specific energy and applied pressure is linear. Because of the protective effect of fine particles, the change of particle size modulus d0 in G-S distribution is not significant, while the distribution parameter α decreases logarithmically with the increase of mass-specific energy. With the decrease of size fraction, the crushability of coal particle bed decreases, and a master curve can be used to fit the comminution characteristics of coal particle bed with different size fractions. The extended G-S distribution model and the JK size-dependent breakage model have better fit the results of coal particle bed comminution. This research provides a useful reference for the mathematical modelling of coal particle bed comminution.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 772-783
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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