Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Theses
    • View Item
    • espace Home
    • espace
    • Curtin Theses
    • View Item

    Modelling and simulation of carbon-in-leach circuits

    192110_Wadnerkar2013.pdf (3.613Mb)
    Access Status
    Open access
    Authors
    Wadnerkar, Divyamaan
    Date
    2013
    Supervisor
    Prof. Vishnu Pareek
    Type
    Thesis
    Award
    PhD
    
    Metadata
    Show full item record
    Faculty
    Faculty of Science and Engineering, Department of Chemical Engineering
    URI
    http://hdl.handle.net/20.500.11937/973
    Collection
    • Curtin Theses
    Abstract

    A CIL circuit is a process of continuous leaching of gold from ore to liquid using a counter-current adsorption of gold from liquid to carbon particles in a series of tanks. It concentrates gold from 2.5-3.5 g/t in ore to 10000 to 15000 g/t on carbon, thus playing an important role on the economics of a gold refinery.In this study, a dynamic model of CIL circuits has been developed to study the transient nature of the system. The effect of various operating parameters on the performance of the system has also been assessed. For example, the particle size and cyanide concentration were predicted to play a critical role on the gold leaching. A decrease in the particle size increased the efficiency of the process, whereas an opposite effect was observed on increasing the cyanide concentration. The recovery also increased on increasing the carbon transfer interval. On the other hand, oxygen concentration did not show a significant effect on the efficiency.The hydrodynamics of CIL tanks is also a complex phenomenon, and it affects both leaching and adsorption kinetics. Current models account for the effect of hydrodynamics in lumped manner. One needs to incorporate the hydrodynamic parameters explicitly in order to make the model applicable over a wider range of operating conditions. Therefore, rigorous CFD simulations of CIL tanks have also been carried out in this study. However, current multiphase CFD simulations require validation especially for interphase closures (such as drag). Therefore, simulations have been conducted using a number of drag models. The modified Brucato drag model was found to be the most appropriate for the CIL tanks, and hence was used in conducting the majority of the simulations in this study. Subsequently, the simulations were conducted to study the effect of various parameters, such as solid loading, and impeller speed and type, on the hydrodynamics of CIL tanks.At low solid loadings, the effect of it on the liquid hydrodynamics was minimal, however, at high solid concentrations, substantial impact on the hydrodynamics was predicted. For example, ‘false bottom effect’ was predicted at very high solid concentration indicates the presence of dead zones. Similarly, at higher solid loadings, higher slip velocities were observed below the impeller, near the wall and near the impeller rod. Finally, the higher solid loadings also caused the dampening of turbulence due to the presence of particles, thus resulting in significant power consumption to counteract this dampening.Other than ore particles, CIL tanks also contain the larger carbon particles. The flow of carbon particles is affected by the flow of ore-liquid slurry. No model is currently available for calculating the drag force on the carbon particles. For obtaining the drag force, a novel macroscopic particle model (MPM) based on RDPM approach was used after validation. The predictions from the MPM model were compared with the available experimental data, and a new drag model has been proposed for the carbon particles in the CIL slurry.The research develops a phenomenological model, validates the drag model for ore particles and proposes a drag model for carbon particles. These models along with the methodology presented in the thesis can be applied on the industrial scale CIL tanks for any ore type provided the rate terms and kinetic constants are known.

    Related items

    Showing items related by title, author, creator and subject.

    • Simulation of solid-liquid flow in stirred tanks at high solid loading
      Wadnerkar, Divyamaan; Utikar, Ranjeet; Tade, Moses; Pareek, Vishnu (2012)
      Solid liquid stirred tanks are commonly used in mineral industry for operations like concentration, leaching, adsorption, effluent treatment, etc. Hydrodynamic study is necessary to evaluate the performance of such systems. ...
    • CFD simulation of solid–liquid stirred tanks
      Wadnerkar, Divyamaan; Utikar, Ranjeet; Tade, Moses; Pareek, Vishnu (2012)
      Solid liquid stirred tanks are commonly used in the minerals industry for operations like concentration, leaching, adsorption, effluent treatment, etc. Computational Fluid Dynamics (CFD) is increasingly being used to ...
    • Coarse grid simulation of gas-solid flows in riser
      Shah, Milinkumar T. (2011)
      Gas-solid risers have been extensively used as multiphase reactors in circulating fluidized bed (CFB) system such as fluid catalytic cracking (FCC) and Circulating fluidized bed combustion (CFBC). In FCC, a riser facilitates ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.