The results of attachment time measured on concentrates were correlated with their Cu grade and collector dosage added during conditioning of flotation pulp. As seen in Fig. 8, at constant collector dosage, the higher the Cu grade, the lower the attachment time. The reason for the drop in the attachment time is not only due to the decrease of Cu grade but also because of the decrease of Cu liberation with the increase of flotation time. In other words,
both Cu grade and Cu liberation affect the attachment time.