Multiplicity of the chemical, biological, electrochemical and operational variables and nonlinear
behavior of metal extraction in bioleaching environments complicate the mathematical modeling
of these systems. This research was done to predict copper and iron recovery from a copper flotation
concentrate in a stirred tank bioreactor using a fuzzy logic model. Experiments were carried
out in the presence of a mixed culture of mesophilic bacteria at 35°
C, and a mixed culture of moderately
thermophilic bacteria at 50°
C. Input variables were method of operation (bioleaching or
electrobioleaching), the type of bacteria and time (day), while the recoveries of copper and iron
were the outputs. A relationship was developed between stated inputs and the outputs by means
of “if-then” rules. The resulting fuzzy model showed a satisfactory prediction of the copper and
iron extraction and had a good correlation of experimental data with R-squared more than 0.97.
The results of this study suggested that fuzzy logic provided a powerful and reliable tool for predicting
the nonlinear and time variant bioleaching processes.
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