| Microbial leaching technology has many advantages such as low investment,simple process,green environmental protection and so on,which has great application prospect in mineral resources recovery and environmental protection.This study aims to develop a fungal bioleaching method for uranium ore.The leaching behavior of uranium ore under various leaching systems was investigated,such as the system of metabolites leaching,direct bioleaching,oxidative-enhanced leaching and dialysis leaching,and the uranium leaching mechanism of P.funiculosum was analyzed.The achievements are summarized as follows:?1?The metabolites leaching experiment was carried out in order to study the effects of metabolites produced by P.funiculosum under varied condition of culture medium type,culture time,spore inoculum concentration and culture temperature on the uranium leaching.The results showed that the pH value of the metabolites produced by P.funiculosum had a great influence on the extraction of uranium which increased with the decrease of the pH value of the metabolites.The pH value of the metabolites was 2.74 and the uranium leaching degree was43.5%under the condition of PCS medium,1‰inoculum concentration30?culture temperature and the 5 days fermentation time.?2?The direct bioleaching experiment was carried out to study the effects of leaching time,pulp density,shaking speed and ore particle size on uranium leaching.The results showed that the uranium leaching degree reached a maximum of 53.9%,when the experimental parameters were PCS medium,30?culture temperature,1‰(OD600=1.0)inoculum concentration,7 days leaching time,5%pulp density,-250 mesh ore particle size and 200 r·min-1 shaking speed.?3?The FeCl3 oxidized-enhanced leaching and dialysis leaching experiments were carried out in which the morphology of P.funiculosum changed accordingly.P.funiculosum has a morphology of irregular filaments clumps in the dialysis bag.In another leaching system,the morphology showed a uniform particle size of the pellets.At the same time,the recovery of uranium increased to 63.5%by addition of FeCl3.?4?By analyzing and comparing the uranium leaching degree and the leaching residues of the each leaching system,it is shown that leaching mechanism of P.funiculosum is the result of the synergistic effect of acidification complex of organic acid and mechanical action of mycelium on ore. |
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