It has been studied the celestite and calcite flotation in Hallimond t
ube using two nonionic surfactants, Ethylan ECD 1274 and Versilan EM-3
0, as collector agents. The results obtained show that both agents hav
e a certain collector property for material sizes lower than 200 mesh
(A.S.T.M.). The effect is concentrations and, in most cases, with pH c
hange. The presence of each surfactant reduces the surface tension of
the flotation bath, although for each agent concentration the pH chang
e does not modify its value.