Effect of different conditions on the leaching of tailings by mixed leaching bacteria

The effects of stirring rate (shake flask group, beaker group), temperature (30°C, 45°C) and slurry concentration (5%, 10%,15%) on the leaching of Cu, Fe and Zn from the tailings were investigated under the initial conditions of pH=2. The leaching rate of copper can reach more than 80% in the shaker group, except that the concentration gradient of 5% pulp in the beaker group is more than 80%, and the other groups are lower than 40%. Therefore, the stirring rate is the key factor affecting copper leaching. The leaching of iron is influenced by temperature, stirring rate and slurry concentration, the first stage is a rapid growth stage, and later the iron concentration will remain stable and no longer increase due to the easy hydrolysis of Fe3+ and the production of jarosite. The leaching of zinc was higher than 80% regardless of the leaching conditions, indicating that zinc was easily recovered by leaching and that the leaching of zinc was less affected by temperature, slurry concentration, and stirring rate. The results showed that, if the three metals in this tailing were to be leached simultaneously, shake flask leaching at 30°C with 5% slurry concentration would be the most favorable leaching conditions. Therefore, appropriate agitation and reduction of slurry concentration in the bioleaching process of tailings will be conducive to the full contact between leaching bacteria and tailings, thus strengthening the leaching of tailings by leaching bacteria.