アルカリ性溶液中における粗粒石英と微粒ヘマタイトの浮選分離とドデシルアミンの吸着

抄録

Cationic flotation of coarse grained quartz (149-210 μm) from an artificial mixture (1: 1 by weight) with fine grained hematite (-10 μm) was investigated in alkaline media (pH 9.8) using dodecyl ammonium acetate as a collector. Individual flotation of quartz and hematite was also carried out for comparison. Flotationresults were discussed in terms of the adsorption density of DAA, zeta potential and scanning electron micrographs.
The results obtained are summarized as follows.
1) Individual flotation tests showed that complete flotation of quartz is achieved at a surface coverage of DAA of about 6%, while the complete flotation of hematite requires as much as 70% of surface coverage of DAA. This behavior of hematite may be explained by assuming that the adsorption of undissociated free amine molecules predominates on fine grained hamatite particles.
2) Negative zeta potential of hematite becomes zero at an adsorption density of DAA corresponding to about 100% of surface coverage. This supports the adsorption mechanism of undissociated free amine molecules on fine grained hematite particles.
3) Floatability of quartz decreased markedly in the presence of hematite fines in spite of the fact that quartz acquires a sufficient amount of surface coverage of DAA, indicating that the depression of quartz flotation can not be interpreted in terms of the collector consumption by hematite fines.
4) Depression of quartz flotation in mixed suspensions is considered to be due to the slime coating of quartz surfaces with hematite fines, where the hydrophobic interaction between quartz and hematite plays an important role.