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Wyszukujesz frazę "libération" wg kryterium: Wszystkie pola

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    Wyświetlanie 1-8 z 8
    Tytuł:
    Effect of intergrown particle liberation on difficult-to-separate coking coal flotation
    Autorzy:
    Gui, X.
    Liu, J.
    Cao, Y.
    Xing, Y.
    Deng, Y.
    Li, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/109875.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    liberation
    particle size
    coking coal
    hydrophobicity
    Opis:
    Flotation tests with intergrown particle liberation were conducted to explore a separation method of difficult-to-separate coking coal from the Tangshan Kailuan mine in China. The particle size distribution, density and coal petrography were investigated. The difficult-to-separate coking coal sample resulted in intergrown particles, such as non-liberated coal and rocks. Thus, intergrown coal particle liberation and re-separation tests were conducted. The results showed that grinding time had a great effect on the flotation performance. Grinding prompted coal to dissociate and improve the surface hydrophobic properties of minerals. However, heterogeneous fine silt covered the surface of coal particles when coal was ground too long. The inorganic mineral particles were over-ground and reduced the contact angle of coal. The results of coal rock dissociation and laboratory re-separation tests showed that clean coal combustible recovery increased through intergrown particle liberation and re-separation.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2016, 52, 1; 279-294
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comminution behavior and mineral liberation characteristics of low-grade hematite ore in high pressure grinding roll
    Autorzy:
    Cao, Jincheng
    Liu, Lei
    Han, Yuexin
    Feng, Ansheng
    Powiązania:
    https://bibliotekanauki.pl/articles/110727.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    low-grade hematite ore
    high pressure grinding roll
    comminution behavior
    degree of liberation
    Opis:
    The comminution process and mechanism of low-grade hematite ore in a high pressure grinding roll (HPGR) were investigated in this work. Three different methods were used for comminution of the hematite ore: HPGR with an air classifier, HPGR with screening followed by ball milling (HPGR+BM), and cone crushing with screening followed by ball milling (CC+BM). In addition, the effects of comminution methods on the degree of liberation of minerals in the grinding products were compared. The results suggest that the comminution process of the ore can be divided into four stages: appearance of tiny cracks, expansion of tiny cracks, which eventually form microcosmic cracks, development of principle cracks, and generation of the conjugate fracturing zone. Intergranular cracks, including partial intergranular cracks and complete intergranular cracks, are apparent in the comminution products of the HPGR. The complete intergranular cracks mainly occur in the conjugate fracturing zone, while the partial intergranular cracks within the particles result in an abundance of locked-particles in the comminution products. Furthermore, the degree of liberation of minerals is more influenced by the final grinding mode rather than the crushing method. It is found that complete intergranular cracks in the conjugate fracturing zone play a significant role in increasing the degree of liberation of iron minerals in the fine size fraction. The “mosaic-type” locked-particles have negligible effect on the liberation properties of iron minerals during the subsequent grinding process.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 2; 575-585
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The relationships between the kinetic grinding parameters with interstitial fillings and the liberation degree of a chromite ore
    Autorzy:
    Umucu, Yakup
    Deniz, Vedat
    Gursoy, Hakan Y.
    Tokcan, Isıl
    Arsoy, Zeyni
    Powiązania:
    https://bibliotekanauki.pl/articles/24148630.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    grinding
    ball mill
    kinetic model
    liberation degree
    interstitial filling
    Opis:
    In this study, the relationships between the liberation degree and the kinetic breakage parameters of a chromite ore obtained from the Burdur (Türkiye) were examined under the laboratory conditions. Firstly, liberation degrees for chromite particles were determined by the particle counting method in a metal microscope for 4 different size groups. Secondly, the breakage parameter of chromite ore which was dry ground with a ball mill was obtained using standard test methods. Additionally, the model parameters were also determined for the fractional interstitial fillings (U) of the chromite sample. Thirdly, the kinetic grinding parameters were compared with the liberation degree of the chromite sample. As a result of the tests, a very good correlation was obtained with R2=0.998, and regression analysis in the grinding processing of the chromite ore was used to verify the validity of the relationship parameter of Si that was produced. To these, it was found that interstitial fillings (U=0.6, 0.8, 1.0, and 1.2) have an effect on the grinding.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 168254
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mineralogical factors affecting the separation behavior of Ta-Nbbearing minerals in the gravity field: mineral grain size, liberation, and association relationship
    Autorzy:
    Cheng, Hongwei
    Xu, Jian
    Wang, Shoujing
    Lv, Zihu
    Wei, Fushuai
    Zhao, Dengkui
    Wu, Dongyin
    Powiązania:
    https://bibliotekanauki.pl/articles/27323650.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    separation behavior
    gravity field
    mineralogical characteristic
    columbite-tantalite
    association relationship
    liberation
    Opis:
    Gravity separation is the primary method used to beneficiate Ta-Nb-bearing minerals, however, it performs poorly in low-grade and fine-grained ores. A comparative study of gravity separation products (concentrate, middlings, and tailings) reveals the factors affecting the separation behavior of Ta-Nb-bearing minerals in the process combined with a spiral chute and shaking table from the perspective of mineralogy. The results reveal that columbite-tantalite is the principal Ta-Nb-bearing mineral. As the grinding time increases, the grade of Ta and Nb in concentrate increases significantly. The grain size of columbite-tantalite in the concentrate is the coarsest, followed by that in the middlings, and the finest in the tailings, which are mainly distributed in the range of -150+38 μm, -75+20 μm, and -38 μm, respectively. The liberation degree of columbite-tantalite in the concentrate and tailings is positively correlated with grinding time, while that in the middlings is negatively correlated with grinding time. The density of columbite-tantalite-bearing particles in concentrate is mainly distributed above 3 or even 4, due to the high liberation degree of the columbite-tantalite in the concentrate, as well as the high amount of rich intergrowth associated with heavy minerals. The density of Ta-Nb-bearing mineral particles in the middlings and tailings is predominantly distributed in D<3, owing to columbite-tantalite mainly associated with lighter gangue minerals such as quartz, albite, and orthoclase. It demonstrates that the liberation degree is not the most essential factor in determining columbite-tantalite separation behavior in the gravity field, and the mineralogical characteristics of columbite-tantalite including grain size, association relationship, and particle density, may be more important. The results of this investigation can provide theoretical support for the strengthening separation of low-grade tantalum-niobium ore.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 174504
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Froth flotation of Aljustrel sulphide complex ore
    Autorzy:
    Sousa, R.
    Futuro, A.
    Pires, C. S.
    Leite, M. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/109732.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    froth flotation
    mineral liberation
    flotation reagents
    complex sulphide ore
    Opis:
    Froth flotation of copper-zinc-lead ores is a complex process based on similar metallurgy processing and strong interactions between chalcopyrite and sphalerite. These types of ores represent 15% of the world production and 7.5% of copper deposits all over the world. In the present study, an attempt is made to assess the feasibility of froth flotation of a complex sulphide ore, where the effect of liberation grade as well as depressant, collector and frother dosage was studied. Copper flotation is dependent on the mineral liberation grade, which is significantly related with the size distribution. It was shown that longer grinding time increased the Cu grade but decreased the copper recovery due to the presence of very fine particles. Lime and sodium metabisulphite, used as depressants, allowed to achieve a good flotation performance. It was shown that for this type of ore lower dosage of the collector should be applied. Finally, a higher frother dosage led to a greater selectivity and reduced entrainment of very fine particles, but also caused low kinetic ratio and low recovery of valuable minerals. A well-defined flotation objective was imperative for a good liberation grade and reagents dosage selection, mainly for complex sulphide ores. A useful contribute was given to a better technical understanding of flotation of a complex sulphide ore from the Moinho deposit.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 2; 758-769
    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:
    Effect of crushing type on the efficiency of flowing film separation
    Autorzy:
    Sirkeci, A. A.
    Gul, A.
    Bulut, G.
    Ozer, M.
    Guven, O.
    Perek, K. T.
    Powiązania:
    https://bibliotekanauki.pl/articles/109918.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    particle shape characteristics
    liberation degree
    chromite
    shaking table
    Opis:
    In recent years, the influence of different crushing systems (compression, impact, attrition) has been receiving more attention due to their significant role on particle liberation and shape of particles. The objective of this study was to investigate the effects of different crushing systems on both liberation degree and shape factors of chromite particles along with their enrichment conditions by shaking table. The tests were conducted on -1+0.5, -0.5+0.212 and -0.212 mm size fractions using the Wilfley type shaking table. The results of these tests showed that concentrates with higher metal contents were obtained by impact crushing of chromite in proportion to higher liberation degree and roundness of particles. Therefore, it was found that selective breakage can well be obtained by impact crushing in all fractions. The results of this study demonstrated the importance of crushing type on the liberation and enrichment processes.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 2; 601-608
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The use of continuous centrifugal gravity concentration in grinding circuit. Modified approach for improved metallurgical performance and reduced grinding requirements
    Autorzy:
    Altun, N. E.
    Sakuhuni, G.
    Klein, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/109786.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    centrifugal gravity concentrator
    grinding
    classification
    liberation
    Opis:
    The use of centrifugal gravity concentration in the closed-grinding circuit of a gold-containing massive sulphide ore was tested on classifier underflow and overflow. A continuous Knelson CVD6 was retrofitted to the hydrocyclone underflow for recovery of Au and Pb at a coarser feed size. The objective of treatment of overflow was recovering unliberated Au prior to flotation. The tests were performed in actual operating conditions at Nyrstar’s Myra Falls Mine. The results of the tests on the cyclone underflow revealed that both liberated and unliberated Au and Pb were recovered by the Centrifugal Variable Discharge (CVD) concentrator. Concentrate grades <60g/Mg Au were attainable at a more than 20% recovery. This application also allowed early and increased Pb recovery before it became gravity unrecoverable by over-grinding. Other benefits included capturing middlings for regrinding as well as potential coarser grinding and increase in mill throughput. A coarse grind also corresponds to a reduction in deformation of Au-particles, and is beneficial for increased Au recovery in downstream processing. Treatment of cyclone overflow by the CVD also provided favourable results. The outcomes included capturing unliberated gold prior to flotation and potentially reducing pumping requirements and reagent consumption. A comparison of the metallurgical performances showed that CVD application on classifier underflow was more effective. The CVD was capable of recovering unliberated gold in sulphides and performed better at a coarser particle size. Therefore, when used with the grinding circuit, a coarser grind can be applied and the CVD could be used to reject gangue at a coarser size.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2015, 51, 1; 115-126
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-8 z 8

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