Mechanisms of bio-dephosphorization from phosphorous iron ore

摘要

Mechanisms of bio-dephosphorization from iron ore was investigated in this Paper. The results show that there are two bio-dephosphorization ways from iron ore, the one is that Acidithiobacillus ferrooxidans directly derive phosphorus from the ore, the other is phosphorus is able to be leached acid produced during metabolizing of Acidithiobacillus ferrooxidans, and the latter is more important than the other. Adding suitable pyrite can enhance the bio-dephosphorization process through providing nourishment and producing acid directly due to S oxidized or indirectly due to Fe~(3+) as oxidant. The potential varies in the range of 0.434～0.498V and pH is in the range of 2.5～1.25 during bio-leaching process. It can be founded that, according to the E-pH graph of Fe-H_2O system, Fe~(2+) wouldn't be oxidized under sterile system in this potential and pH ranges. It can be obviously concluded that the Acidithiobacillus ferrooxidans are able to reduce the potential for the oxidization of Fe~(2+) and make the oxidization occur in the above pH and potential zone, so the bio-leaching process can proceed, the investigation of E-pH graph of P-H_2O system show that H_3PO_4 can exist steadily.