The interactions between chalcopyrite and kaolinites of different crystallinity, over the pH range from 7 to 12, are studied. The tests were carried out in seawater, and in a 0.01 M NaCl solution. The effect of the dispersants, sodium hexametaphosphate (SHMP) and sodium silicate (SS) was evaluated. The results show that both tested dispersants are able to restore chalcopyrite flotation in the presence of kaolinite in seawater over the pH range from 7 to 11.