SPATIAL VARIATIONS OF PULP PROPERTIES IN FLOTATION - IMPLICATIONS FOR
OPTIMIZING CELL DESIGN AND PERFORMANCE
Lisa Malma, Anders Sandb, Jan Rosenkranzc, Nils-Johan Bolind
a)
Boliden Mineral AB
93632 Boliden, Sweden
+46 910 77 44 00
Lisa.Malm@boliden.com
b)
Division of Minerals and Metallurgical Engineering / Mineral Processing
Luleå University of Technology, 971 87 Luleå, Sweden
+46 920 49 1000
Anders.Sand@ltu.se
c)
Division of Minerals and Metallurgical Engineering / Mineral Processing
Luleå University of Technology, 971 87 Luleå, Sweden
+46 920 49 1000
Jan.Rosenkranz@ltu.se
d)
Boliden Mineral AB
93632 Boliden, Sweden
+46 910 77 44 00
Nils-Johan.Bolin@boliden.com
ABSTRACT
Within flotation technology the general trend is towards very large cells. Scale-up is usually done by
postulating geometrical similarity, which implies keeping the aspect ratio constant when increasing cell
volume. Consequently, the design of flotation circuits typically involves several cells of identical geometry
within a bank. Using a few standard sizes in a flotation plant simplifies design, manufacturing and
maintenance of the cells, but does not necessarily guarantee optimal performance and selectivity of the
flotation process.
Geometry parameters that for a given cell volume influence flotation cell performance include cell height,
which causes changes in the hydrostatic pressure and suspension hydrodynamics, and influences the travel
distance of particle-bubble agglomerates as well as the homogeneity of the mixing. Also the thickness of
the froth layer depends on the aspect ratio of the cell. The objective of this work is to gain a better
understanding of material distribution and properties within a flotation cell and, based on this information,
elucidate how alterations of the cell geometry can influence separation efficiency.
For this purpose systematic measurements and analyses of the spatial distribution of the different phases
within a 160 m3 flotation cell have been carried out with a particular focus on an industrial, low-grade
copper ore beneficiation process. The concepts for sampling at different vertical and lateral positions of the
flotation cell are introduced. The results from the experimental work give an understanding of internal
material distribution within flotation cells. Based on the measured phase distribution and concentrations as
well as particle properties at various positions within the cell, the implications for an optimized scaling and
design of individual flotation cells within a flotation circuit are discussed.
KEYWORDS
Flotation, Pulp composition, Sampling, Cell dimensioning, Circuit design