Abstract
The use of metal chelators, such as diethylenetriamine (DETA), during flotation of nickel-copper ores can greatly improve the depression of pyrrhotite, and hence the recovery grade. However, DETA renders chelated metals soluble at high pH levels, preventing their precipitation during tailings clarification. Mobilization of metals in this manner is damaging to the environment and violates governmental regulations. For DETA to be used safely a mitigation strategy must be in place to remove the chelated complexes. The objective of this study is to investigate biodegradation as a mitigation strategy for DETA-metal chelates. Biodegradation is a process which uses bacteria to breakdown polymers with biodegradable linkages; the biodegradation of DETA would release the chelated metal ions for recovery. Preliminary results have shown that a mixed bacteria culture is capable of degrading unchelated DETA and Ni-chelated DETA in the presence of an added carbon and energy source. However, Cu-chelated DETA showed no signs of biodegradation.