Effects of grain size gradation on the porosity of packed heap leach beds

Shuo Zhang, Wenying Liu, Giuseppe Granata

    Research output: Contribution to journalArticle

    2 Citations (Scopus)

    Abstract

    Fluid flow through packed ore/rock beds is among the critical processes that control the release of valuable metals as well as substances potentially harmful to the environment. The properties of fluid flow in porous media are associated with the structure of the pores through which the fluid flows which, in turn, is influenced by grain size gradation, grain shape and packing method. In this study, we investigated the effect of three types of grain size gradation on porosity and pore size distribution using the bulk density and the computed tomography (CT) scanning methods. It was generally observed with the uniformly graded grains that the porosity decreased as the mean grain size increased until a limit was reached. The porosities of the well graded grains were lower than those of the uniformly graded grains in the coarse size range, but there was no difference in the porosities between the two types of gradation in the fine size range. Furthermore, the influence of the packing method on the well graded grains was more pronounced than on the uniformly graded grains, implying relative ease of compaction of well graded grains. The proportion of fine grains in the gap graded grains influenced the porosities, which firstly decreased and then increased. The pore size distribution of the gap graded grains showed a high degree of heterogeneity compared to those of the uniformly graded and the well graded grains. The findings indicate that in ore/rock dumps fine particles account for the bulk of the porosity and possibly the bulk of any pore water content, suggesting that fine particles are likely to contribute most of the leachable substances.

    Original languageEnglish
    Pages (from-to)238-244
    Number of pages7
    JournalHydrometallurgy
    Volume179
    DOIs
    Publication statusPublished - 2018 Aug 1

    Fingerprint

    Porosity
    Flow of fluids
    Ores
    Pore size
    Grain size and shape
    Rocks
    Density (specific gravity)
    Water content
    Process control
    Tomography
    Porous materials
    Compaction
    Metals
    Scanning

    Keywords

    • Fluid flow
    • Heap/dump leaching
    • Packed bed permeability
    • Pore size distribution
    • Waste rock drainage

    ASJC Scopus subject areas

    • Industrial and Manufacturing Engineering
    • Metals and Alloys
    • Materials Chemistry

    Cite this

    Effects of grain size gradation on the porosity of packed heap leach beds. / Zhang, Shuo; Liu, Wenying; Granata, Giuseppe.

    In: Hydrometallurgy, Vol. 179, 01.08.2018, p. 238-244.

    Research output: Contribution to journalArticle

    Zhang, Shuo ; Liu, Wenying ; Granata, Giuseppe. / Effects of grain size gradation on the porosity of packed heap leach beds. In: Hydrometallurgy. 2018 ; Vol. 179. pp. 238-244.
    @article{af22120bfc5c4d6d97554547461c5972,
    title = "Effects of grain size gradation on the porosity of packed heap leach beds",
    abstract = "Fluid flow through packed ore/rock beds is among the critical processes that control the release of valuable metals as well as substances potentially harmful to the environment. The properties of fluid flow in porous media are associated with the structure of the pores through which the fluid flows which, in turn, is influenced by grain size gradation, grain shape and packing method. In this study, we investigated the effect of three types of grain size gradation on porosity and pore size distribution using the bulk density and the computed tomography (CT) scanning methods. It was generally observed with the uniformly graded grains that the porosity decreased as the mean grain size increased until a limit was reached. The porosities of the well graded grains were lower than those of the uniformly graded grains in the coarse size range, but there was no difference in the porosities between the two types of gradation in the fine size range. Furthermore, the influence of the packing method on the well graded grains was more pronounced than on the uniformly graded grains, implying relative ease of compaction of well graded grains. The proportion of fine grains in the gap graded grains influenced the porosities, which firstly decreased and then increased. The pore size distribution of the gap graded grains showed a high degree of heterogeneity compared to those of the uniformly graded and the well graded grains. The findings indicate that in ore/rock dumps fine particles account for the bulk of the porosity and possibly the bulk of any pore water content, suggesting that fine particles are likely to contribute most of the leachable substances.",
    keywords = "Fluid flow, Heap/dump leaching, Packed bed permeability, Pore size distribution, Waste rock drainage",
    author = "Shuo Zhang and Wenying Liu and Giuseppe Granata",
    year = "2018",
    month = "8",
    day = "1",
    doi = "10.1016/j.hydromet.2018.06.014",
    language = "English",
    volume = "179",
    pages = "238--244",
    journal = "Hydrometallurgy",
    issn = "0304-386X",
    publisher = "Elsevier",

    }

    TY - JOUR

    T1 - Effects of grain size gradation on the porosity of packed heap leach beds

    AU - Zhang, Shuo

    AU - Liu, Wenying

    AU - Granata, Giuseppe

    PY - 2018/8/1

    Y1 - 2018/8/1

    N2 - Fluid flow through packed ore/rock beds is among the critical processes that control the release of valuable metals as well as substances potentially harmful to the environment. The properties of fluid flow in porous media are associated with the structure of the pores through which the fluid flows which, in turn, is influenced by grain size gradation, grain shape and packing method. In this study, we investigated the effect of three types of grain size gradation on porosity and pore size distribution using the bulk density and the computed tomography (CT) scanning methods. It was generally observed with the uniformly graded grains that the porosity decreased as the mean grain size increased until a limit was reached. The porosities of the well graded grains were lower than those of the uniformly graded grains in the coarse size range, but there was no difference in the porosities between the two types of gradation in the fine size range. Furthermore, the influence of the packing method on the well graded grains was more pronounced than on the uniformly graded grains, implying relative ease of compaction of well graded grains. The proportion of fine grains in the gap graded grains influenced the porosities, which firstly decreased and then increased. The pore size distribution of the gap graded grains showed a high degree of heterogeneity compared to those of the uniformly graded and the well graded grains. The findings indicate that in ore/rock dumps fine particles account for the bulk of the porosity and possibly the bulk of any pore water content, suggesting that fine particles are likely to contribute most of the leachable substances.

    AB - Fluid flow through packed ore/rock beds is among the critical processes that control the release of valuable metals as well as substances potentially harmful to the environment. The properties of fluid flow in porous media are associated with the structure of the pores through which the fluid flows which, in turn, is influenced by grain size gradation, grain shape and packing method. In this study, we investigated the effect of three types of grain size gradation on porosity and pore size distribution using the bulk density and the computed tomography (CT) scanning methods. It was generally observed with the uniformly graded grains that the porosity decreased as the mean grain size increased until a limit was reached. The porosities of the well graded grains were lower than those of the uniformly graded grains in the coarse size range, but there was no difference in the porosities between the two types of gradation in the fine size range. Furthermore, the influence of the packing method on the well graded grains was more pronounced than on the uniformly graded grains, implying relative ease of compaction of well graded grains. The proportion of fine grains in the gap graded grains influenced the porosities, which firstly decreased and then increased. The pore size distribution of the gap graded grains showed a high degree of heterogeneity compared to those of the uniformly graded and the well graded grains. The findings indicate that in ore/rock dumps fine particles account for the bulk of the porosity and possibly the bulk of any pore water content, suggesting that fine particles are likely to contribute most of the leachable substances.

    KW - Fluid flow

    KW - Heap/dump leaching

    KW - Packed bed permeability

    KW - Pore size distribution

    KW - Waste rock drainage

    UR - http://www.scopus.com/inward/record.url?scp=85049325291&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=85049325291&partnerID=8YFLogxK

    U2 - 10.1016/j.hydromet.2018.06.014

    DO - 10.1016/j.hydromet.2018.06.014

    M3 - Article

    VL - 179

    SP - 238

    EP - 244

    JO - Hydrometallurgy

    JF - Hydrometallurgy

    SN - 0304-386X

    ER -