Information Only - Waste Isolation Pilot Plant - U.S. Department of ...

V-3
and reduced power costs. These improvements justified replacement of two banks of
rougher cells and one bank of cleaner cells with column cells at the Cleveland Potash,
Ltd. plant (Burns et al., 1994).
Decreasing ore grades in the Carlsbad District would require fmer grinding of ores to
meet the product grade standard. It is, therefore, reasonable to assume that-most flotation
circuits in the District would benefit from the column cell technology, and it is likely that
aging mechanical Cc ,$ will eventually be replaced by column cells, particularly in the
cleaning circuits.
Plant control
!MC Esterhazy Q,:,erations improved plant efficiency by on-stream analysis of ore,
improved flotation re ,;:~nts and reagent control",centralized process control, and improved
energy efficiency of the operation (Ma.yor, 1983). Implementation of such
modifications in process control can be expected in most operations in the Carlsbad
District.
Electrostatic separation
Potash operations in Germany (Singewald and Neitzel, 1983) and pilot plant trials at
PCS Mining in Canada (Larmour, 1983) have shown that electrostatic separation is a
viable alternative to flotation and heavy-media processes. The advantages to be gained by
dry processing are both environmentally and economically significant. The process
requires conditioning the ore with reagents in a controlled-humidity environment, and
passing the ore through a separator where different minerals are attracted to oppositely
charged electrodes. Reportedly, this process was developed and extensively tested in
pilot-plant trials at IMC's Carlsbad plant, but the details of these tests have not been
disclosed (Zandon, 1985).
Heavy-media separation
As discussed above, heavy-media separation (HMS) is used m the Carlsbad 'J1Strict
for langbeinite processing. In this process, a fme suspension of magnetite is used to
provide a medium in which the coaT' aeavy mineral (langbeinite) sinks and the light
minerals (sylvite, halite) float. Usually, a cone- or drum-type vessel is used to facilitate
separation and the medium (magnetite) is recovered from the screen undersize by
magnetic.separators. Heavy-media cyclones, which are widely used in coal cleaning, can
exploit much smaller differences in the specific gravity ofthe mlnerals than conventional
separators. For example, IMC's Esterbazy operations in Canada reportedly prcx.;:"ce
substanual tonnages of crystalline muriate from sylvinite ores (Zandon, 1985). Sylvinite
ores in the Carlsbad District are known to have·finer grain size than the Esterhazy ores,
however, potential exists for wider use of heavy-media processes, particularly in
langbeinite preconcentration prior to leaching and in processing mixed ores.
Solution mining, purification, crystallization
Thinly-bedded deposits.c·;;arcity of fresh-water supplies, and high solution tempera-
Information Only