| In this paper, different methods to increase the leaching rate of chalcopyrite are briefly reviewed. These methods include the addition of silver ion, surfactants, and hematite into the leaching solution, respectively; and the application of electric voltage, magnetic field, and ultrasonic, etc. to the leaching system. It is discussed emphatically that the microwave techniques can be applied to mineral processing and metallurgy and that there are great potentialities with the application of microwave techniques to increase the metallurgical efficiency. Finally, the future work which would be done is suggested.Under the condition of pH of 2.0, the different inoculum amount, slurry densities and culture medium with different amount of iron concentrations, bioleaching rate of copper in chalcopyrite was investigated. " 3 factors and 3 levels" orthogonal design have shown that the effect in order: slurry density was preferential. The culture medium and inoculum amount were less preferential and closed to each other. Variance analysis showed that the effect of slurry densities is highly significant. At the same time with single-factor tests the optimal conditions for bioleaching have been determined: the slurry density is 5%, 9 K medium without iron ion, the inoculum amount is 10%The medium was prepared with water which treated by microwave or magnetic fields to strengthen, and founded that the activity of bacteria in the medium was increased. The function of microwave is more obvious and effective than magnetic field. As far as the effect of improving the activity of bacteria is concerned, the water which treated in microwave oven the middle grade power of the long time and higher grade of short time is better. In addition, microwave heating is concerned to volume, presented as the impact of penetration depth. Therefore, when dealing with water the containers have an impact on the experimental results. The medium prepared with water magnetized after half an hour can increase the activity of T.f. However, the effect of magnetized one hour is no good than half an hour.Under the optimal conditions, comprehensive bioleaching of chalcopyrite was studied. The culture medium was prepared with water treated by microwave and magnetic field, respectively. It was found out that the bioleaching rate of thiobacillus ferrooxidans (T. f) in the treated culture medium was higher than that in the untreated one. Finally the leaching effects of T.f in the culture medium treated by both microwave and magnetic field were compared with the general treatment under the conditions, respectively. And the order is almost coincident with bacterial comprehensiveness, in general. The comprehensive mechanism has to be further investigated.As the method used in this experiment is only concerned to the treatment of water for medium. So it does not affect the application of other chemical comprehensive bioleaching, and is valuable for bioleaching of other minerals. This method of comprehensive bioleaching has advantage of less harm to environment, less investment and lower energy consumption. |
