Improving Bioleaching Rate Using Immobilized Cell Reactor

In the traditional bioleaching progress of refractory gold ore, bacteria lives with pulp density directly, the steadily accumulated poison and harmful ion,the huge shearing force produced by stirring and the high density blocks the transformation of O₂ and CO₂, all these affect bacteria growth and activity, leading to low oxidation rate of Fe²⁺, longing the leaching time, which limit the apply of the bioleaching technology.In order to increase the leaching rate, base on the indirect mechanism, this thesis adopts Indirect Bioleaching with Effects Separation process, imparts the two stages of bioleaching, so that both stages can react in their own condition which can rise the rate of two stages separately, shorter the whole reaction time. In the experiment, we use cell immobilization technique to enhance the bacteria activity, the carrier is polyurethane foam, bacteria using in the immobilization are Acidithiobacillus ferrooxidants and Sulfobacillus sibiricu,the target mineral is rich-arsenic gold concentration. The result is, the rate of S.s oxidize Fe²⁺ is raised by immobilization, under the air rate of 4L/min, 10g/L Fe²⁺ converse 95% takes 5h by immobilization S.s, which is one-seventh of the 10% free S.s (36h). The system of acid ferric sulfate solution leaching rich-arsenic gold concentration is better than bioleaching system, at 70℃, the leaching rate of rich-arsenic gold concentration achieve 71% takes 4 days by 10g/L Fe3+ solution. The result show that IBES progress leaching rich-arsenic gold concentration is more effective.