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Magnetic seeding depression in flotation of hematite ore slimes

Yue T., Wu X.

Physicochemical Problems of Mineral Processing

2018

Vol. 54, iss. 3

701--712

Magnetic seeding depression (MSD), i.e. adding organic depressant (such as starch) and magnetic seeds and applying a low field intensity pre-magnetization for depressing target mineral in flotation, was investigated in the reverse flotation of hematite ore slimes. Flotation tests found that the iron recovery increased with the addition of magnetic seeds; the depressing ability of starch in flotation was further enhanced by the MSD. The increased adsorption density of starch on target mineral hematite and apparent size enlargement of fine minerals are two reasons for the MSD. Based on FTIR, VSM and AFM measurements it was demonstrated that the starch acted as a bridging adsorption between hematite and magnetic seeds by hydrogen bonding and chemisorption, and resultant coverage of the magnetic seeds and starch on hematite increased the magnetic susceptibility, being beneficial to the agglomeration of hematite fines by reducing the external magnetic intensity needed for agglomeration to take place. The model of the MSD was proposed.

Fast and sensitive spectrofluorimetric determination of trace amount of Pb(II) in sludge using o-vanilin-8-aminoquinoline

Tang B., Yue T., Wu J., Ding Y., Dong Y., Wang H.

Chemia Analityczna

2005

Vol. 50, No. 3

631-639

o-Vanillin-8-am inoqu incline (OVAQ) — a novel fluorescent reagent has been synthesised and applied to the determination of Pb(II). In ethanol-water medium of pH 9.00 Pb(ll) reacted with OVAQ (&lambdaex/em= 278/318 nm) to form a 1; 1 non-fluorescent complex. Fluorescence quenching was proportional to the concentration of Pb(ll) in the range from 5.3 to 180 &mug L-1. Detection limit was 1.6 μg L-1. Interfering effect of 25 foreign ions on the determination results were studied. The method was successively applied to the determination of lead in sludge.

Zsyntetyzowano nowy odczynnik fiuorymetryczny o-wanilino-8-aminochinolinę (OVAQ) 1 wyznaczono jego stale dysocjacji kwasowej. Zbadano reakcję fluorescencji odczynnika w obecności jonów oiowiu. W wodno-etanolowym roztworze o pH 9.0 Pb(II) reaguje 2 fluoryzującym (&lambdaex/em= 278/318 nm) odczynnikiem tworząc nie fluoryzujący kompleks o składzie 1:1. Wyznaczono liniowy zakres wykresu analitycznego od 5,3 do 180 μg -1 i granicę wykrywalności wynoszącą 1,6 μg L-1. Badano interferencje 25 jonów. Metoda jest prosta i została z powodzeniem zastosowana do oznaczania ołowiu w osadach.