Bioleaching Process Control

Abstract

A process of bioleaching a sulphide mineral slurry in a reactor which is controlled by varying the rate of supply of sparging gas to the reactor, and the energy supplied to a motor-driven agitator in the reactor, in response to the measured or inferred oxygen demand of the slurry.

1 . A method of conducting a bioleaching process which includes the steps of feeding a sulphide mineral slurry to a reactor, sparging the slurry in the reactor with a gas, agitating the slurry in the reactor with a motor-driven agitator, causing biooxidation of the sulphide mineral to take place, and controlling the rate of supply of the sparging gas to the reactor and of the energy supplied to the motor in response to at least one of the following measured oxygen demand and inferred oxygen demand. 
     
     
         2 . A method according to  claim 1  that includes the steps of deriving data which is dependent on the rate of supply of the sparging gas to the reactor and the composition of an off-gas from the reactor, and calculating the oxygen demand from the derived data. 
     
     
         3 . A method according to  claim 1  wherein the oxygen demand is dependent on the power which is drawn by the motor-driven agitator, the rate of supply of the sparging gas to the reactor, and the dissolved oxygen level in the slurry. 
     
     
         4 . A method according to  claim 1  that includes the step of reducing the rate of feeding the slurry to the reactor if the sulphide grade of the slurry is reduced.