Modelization of bacterial leaching besides kinetic and physiologic studies will ultimately provide the information required to understand and control the process of bacterial leaching. In this review, the models are classified into three categories. In the first, the models are simple modifications of
Carbon use efficiency (CUE) is a fundamental parameter for ecological models based on the physiology of microorganisms. CUE determines energy and material flows to higher trophic levels, conversion of plantproduced carbon into microbial products and rates of ecosystem carbon storage.
KINETIC ELEMENTS IN THERMOPHILIC MICROBIAL LEACHING OF SULFUR FROM COAL Charles C. Y. Chen and Duane R. Skidmore Department of Chemical Engineering Columbus, Ohio 43210 ABSTRACT A mechanism found suitdble for pyritic sulfur removal from coal by mesophilic organisms has been modified and evaluated for the same reaction
A robustious structural model is developed to describe the role of bacteria in the leaching process of lowgrade ores under conditions controlled by intraparticle diffusion. The main impetus behind developing this model is to provide an insight into such systems, together with a suitable framework for interpreting experimental data.
The biofilm lifestyle protects cells from environmental stresses such as desiccation, nutrient starvation, radiation, and oxidative stress (Flemming and Wingender 2010). The process of biofilm formation by mineral oxidizing bacteria on metal sulfides is not completely understood.
leaching models for the development of a model that can predict both recovery and reagent consumption using available mineralogical data. The envisaged model will be used as a tool for predicting hydrometallurgical routes from mineralogical data. The development of a hydrometallurgical process is a vital step in designing a mineral
(A) Plot of the bacterial leaching data from Fig. 2A, confirming that the shrinking particle model with surface reaction control describes the leaching of sphalerite in the presence of bacteria at high concentrations of Fe3 Fe2 K 3De ZnSd2 t (6) ferrous ions.
Product Structure. Air is fed in tank from the lower end of shaft, and blended with ore pulps to form uniform suspending mixed liquid. In the gold cyaniding process, leaching agitation tank is applied to leach and carbon absorb ore pulps whose fineness is 200 meshes and whose density is less than 45%.
Microbial Leaching Process to Recover Valuable Metals from Spent Petroleum Catalyst Using Iron Oxidizing Bacteria Debabrata Pradhan, Dong J. Kim, Jong G. Ahn, and Seoung W. Lee AbstractSpent petroleum catalyst from Korean petrochemical industry contains trace
To enable useful predictions of the heap leach process many different simulation approaches have been developed from simple spreadsheets to complex phenomenological models. There are considerable differences in the various heap leach models, and the modelling method employed to of microbial activity in acid ferric sulphate leaching [50,51
The thin layer leaching process originally conceived and developed for leaching oxide ores has been successfully adapted to bacterial leaching of mixed and secondary sulphide ores. The process is currently being applied at the Socicdad Minera Pudahuel Lo Aguirre Plant.
the leaching solution percolating through the ore bed. Early models involved two dimensional governing equations to describe the diffusion and the convection of air into the pore spaces of the heap/dump [1, 2]. It was widely held that the supply of oxygen to the acidophilic bacteria colonizing the ore surfaces was the rate limiting process.
Commercial leaching of sulphide ores by microorganisms is used in numerous oxidation situations as a scavenger process for treating low grade ores and very dilute metal waste streams at comparatively low capital and operating costs compared with conventional hydrometallurgical processes.
shrinking core model. Activation energy for nickel leaching was The extraction of metal values from laterites/Chromite also determined in addition to kinetics study to further support overburdens through the conventional pyrometallurgy and the kinetic models involve in the process.
Microbes such as bacteria and fungi convert metal compounds into their water soluble forms and are biocatalysts of these leaching processes. Additionally, apply ing microbiological solubilization processes, it is possible to recover metal values from in dustrial wastes which
Microbial Leaching of Uranium Ore. 295 However, the model of direct and indirect metal leaching is still under discussion. Recently, this model has been revised and replaced by another one which is not dependent upon differentiation between a direct and an indirect leaching mechanisms. (a) (b) Fig.
Copper is primarily produced by smelting and refining (80% of worldwide production), followed by oxide heap leaching (13%), secondary copper sulphide heap leaching (5%), and other hydrometallurgical routes such as concentrate pressure leaching and bacterial leaching.
Leaching occurs in metals recovery, in contaminated soil washing, and in many natural processes, such as fertilizer dissolution and rock weathering. This paper presents a model developed to simulate the transient evolution of the dissolved chemical species in the
Microbial Leaching (Bioleaching, Biomining) Microbial leaching is the process by which metals are dissolved from ore bearing rocks using microorganisms. For the last 10 centuries, microorganisms have assisted in the recovery of copper dissolved in drainage from water. Thus biomining has emerge as an important branch of biotechnology in recent years.
In this article we will discuss about some examples of leaching. 1. Copper Leaching Copper leaching is practical, feasible and in use throughout the world for many years. In this process, the leaching solution contains sulphate and iron carries the microbial nutrients in and dissolved copper out. The copper containing solution is precipitated.
Microbial systems used for bioleaching. Heap height is an important factor in the temperature rise, which increases with the square of heap height (Ritchie 1997 ). Other factors important in heap heating include sulfide oxidation rate, aeration and irrigation rates, and the local climate (Dixon 2000 ).
Microbial batch leaching experiments designed according to a central composite design model were run for 15 days in a shaking incubator (150 rpm) at a constant temperature (30C) with variations in experimental parameters like ore pulp density, particle size, bacterial inoculum, pH of the culture medium, and residence time.
HB is the average heap height, and S. HB is the average heap top surface. In partial summary, the proposed mathematical model to the heap and column leaching process uses a diffusive control model to describe the solid fluid reaction and the plug flow assumption to describe the solution flow in
removed during the leaching process. Key Words Model, Prediction, Phosphorus Removed, Sulphuric Acid, P = Concentration of phosphorus removed during the leaching process (mg/Kg) the flask was assumed to be initially free of attached bacteria and other micro organism.