Evaluation of residence time distribution and mineralogical characterization of the biooxidation of sulfide minerals in a continuous stirred tank reactor

摘要

The residence time distribution (RTD) of the liquid phase and the mineralogical characterization of the biooxidation of refractory gold mineral was studied in a continuous stirred tank reactor. The latter was achieved using a native mixed culture of acidophilic mesophiles. The RTD was assessed using a mathematical model of stirred tanks in parallel. The oxidation of sulfide and the phases generated through the biooxidation process were evaluated via X-ray diffraction (XRD).The results indicated that the experimental RTD fit to the model. The reactor has a high tendency to behave as a completely mixed reactor. However, the mixed flow inside the reactor has disturbances such as by-pass and dead zones. The estimated mean residence time for the model was approximately 36% greater than the theoretical residence time. It was probably caused by the delay in the outflow of the tracer due to gas hold-up, foaming at the top and the design of the reactor outlet structure. The XRD outcomes showed that the oxidation of arse-nopyrite was greater than that of pyrite. Similarly, the formation of jarosite and brushite was observed. It was concluded that the dead zones could increase the probability of jarosite precipitations.