Calcium removal from bauxite using Paenibacillus polymyxa

Modak, J. M. ; Natarajan, K. A. ; Vasan, S. S.
Organization: Society for Mining, Metallurgy & Exploration
Pages: 7
Publication Date: Jan 1, 2000
The biological removal of calcium from a bauxite ore in the presence of the soil bacterium Paenibacillus polymyxa is demonstrated. A column bioreactor that can be either operated in a fluidized-bed (FB) mode for coarser particles or in a total-recycle-slurry (TRS) mode for finer particles was designed, fabricated and tested for this purpose. For the efficient removal of calcium from the ore to the required levels, leach solution should not be allowed to accumulate in the reactor. Therefore, the solution needs to be drained out periodically. Cascade leaching was found to be more effi¬cient. A direct correlation between pH changes in the leach solution and calcium solubility could be made. More than 85% of the calcium could be removed through cascade leaching.
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