Premium
Focused beam reflectance measurement for monitoring the extent and efficiency of flocculation in mineral systems
Author(s) -
Senaputra Alexander,
Jones Franca,
Fawell Phillip D.,
Smith Peter G.
Publication year - 2014
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.14256
Subject(s) - flocculation , chord (peer to peer) , optics , mineralogy , reflectivity , sapphire , materials science , chemistry , environmental science , laser , physics , environmental engineering , computer science , distributed computing
Focused beam reflectance measurement (FBRM), where a scanning laser focused through a sapphire window measures real‐time reflected chord distributions without solids dilution, is attractive for characterizing flocculation performance. An enhanced measurement principle in new FBRM instruments has implications for flocculation studies, demonstrated using hematite in synthetic Bayer liquor. Comparisons of previous (M500) and new (G400) instruments were complicated by the impact of their different physical dimensions upon flocculation hydrodynamics, but the G400 clearly measured larger chords. The original measurement principle based on a reflected intensity threshold counts large low‐density aggregates as multiple chords; in contrast, the change to “edge detection” (very low threshold) is more likely to see a single chord, an advantage for studying mineral systems (aggregates often >500 µm). The G400 also captures bimodal character in unweighted chord distributions, producing distinct peaks for aggregates and fines after suboptimal flocculation; such peaks are rarely well resolved in older FBRM. © 2013 American Institute of Chemical Engineers AIChE J , 60: 251–265, 2014