The world market for rare-earths elements is increasing due to the dev
elopment of new products and applications, resulting in the need for t
echnology to treat deposits having highly complex mineralogy, such as
that of Pitinga, AM, Brazil, with estimated reserves of 146,960 t of r
are-earths oxides (REO), including Y2O3. Mineralogically the mine of P
itinga is very rich. The initial and major target of the company Paran
apanema was the production of tin concentrates from placer deposits an
d later from primary ore. However, geological studies identified sever
al other minerals of potential economical importance, such as: columbi
te-tantalite, zircon, cryolite and xenotime, the objective of the pres
ent investigation. The response of a pre-concentrate sample of the non
-conducting fraction from Pitinga's electrostatic separator to laborat
ory scale physical concentration methods was very poor. Another possib
ility for the selective separation of xenotime and zircon (the major a
ssociated mineral) is flotation. Microflotation experiments were perfo
rmed in a modified Hallimond tube with pure samples of xenotime and zi
rcon, in the presence of hydroxamate as collector and five different r
eagents as depressants. The zeta potential of xenotime and zircon was
determined in the presence of supporting electrolyte and hydroxamate.
(C) 1997 Elsevier Science Ltd.