Takakatsu Takamori

Effects of Phospholipid on Bacterial Leaching of Chalcopyrite Concentrate by Thiobacillus ferrooxidans. Effects of phosphatidyglycerol.

Some kinds of phospholipids have been detected as extracellular substance during the culture of Thiobacillus thiooxidans and Thiobacillus ferrooxidans, and during the pyrite leaching by Thiobacillus ferrooxidans. In this paper, the function of phospholipid in bacterial leaching of chalcopyrite concentrate by Thiobacillus ferrooxidans was investigated, using phosphatidylglycerol as a phospholipid.Phosphatidylglycerol was observed to be adsorbed on chalcopyrite surface. As ferric ions would be inhibited to react with the chalcopyrite due to the adsorbed layer of phosphatidylglycerol, the amount of copper chemically leached with ferric sulfate become small with increasing phosphatidylglycerol addition. In the medium containing ferrous sulfate as substrate, growth of Thiobacillus ferrooxidans and iron oxidation from ferrous to ferric by the microorganisms were delayed with phosphatidylglycerol addition. On bacterial leaching, copper extraction was decreased with increasing phosphatidylglycerol addition. The leaching results were interpreted in terms of the functions of phosphatidylglycerol, which influenced the main reaction of indirect leaching mechanism.

Reactions between ions of some collectors and constituent ions of salt-type minerals.

The authors have studied the reactions between ions of various collectors and the constituent ions of salttype minerals such as bastnaesite, apatite, fluorite, barite, rhodochrosite. The collectors used were sodium oleate (NaOl), n-oleoylsarcosine (OLSA), sodium octadecylsulfosuccinamate (SOSS), n-tallow-1, 3-diaminopropane dioleate (TDO), sodium dodecylsulfate (SDS) and dodecylammonium acetate (DAA).Precipitate formation was monitored using a nephelometer. The solubility products of the precipitates of metal ions with SDS, NaOl and OLSA were determined by utilizing the Debye-Huckel law. The minimum concentrations of metal ions and anions needed to form precipitates with SOSS, TDO and DAA were measured. SOSS, OLSA, TDO and SDS preferentially reacted with Ce, La and Ba ions compared with Ca and Mn ions. Selective flotation of salt-type minerals with non-fatty acid type collector was discussed on the basis of the precipitate formation test results.DAA and TDO formed precipitate of tungstate, sulfate, phosphate and carbonate but did not form with fluoride ions even at a high concentration. The adsorption mechanisms of SDS and DAA on typical salt-type minerals were interpreted in terms of the stability of the precipitates.