TITLE:
Factors Affecting Fines Flocculation Performance with Cofactor-Polyethylene Oxide
AUTHORS:
M. R. Abdallah Qasaimeh, Ahmad Qasaimeh, F. Bani Hani
KEYWORDS:
Polyethylene Oxide; Cofactor; Flocculation; Shearing and Bridging
JOURNAL NAME:
Advances in Chemical Engineering and Science,
Vol.4 No.1,
January
24,
2014
ABSTRACT:
In literature, neutral polyethylene oxide (PEO)
flocculated fines at low shear rates, while with cofactor (CF) addition, the
formed CF-PEO complex showed larger ability to bridge fines, producing flocs.
In this work, some process factors were found having significant effects on
fines flocculation. Increases in CF to PEO ratio at constant PEO enhanced the
bridging bonds, causing increases in flocculation initial rate (efficiency),
amplitude (floc size), and fastness (a decrease in characteristic time). On the other
hand, an increase in stirring rate (shear rate) in flocculation vessel caused
decreases in initial rate and amplitude, and an increase in the
fastness. All runs showed transient flocculation; the amplitude increased with
time, reached maximum at equilibrium, and then started to decrease showing
deflocculation. In brief, the CF to PEO ratio and the shear rate were found important
parameters in mill operation, having significant effects on flocculation
efficiency, fastness, and floc size.