The use of seawater in copper and molybdenum flotation

Nowadays, seawater usage in mineral processing has become a fairly topical issue. Due to rapid population growth and industrial development, the amount of fresh water is decreasing rapidly, so that fresh water is a critical component, especially in many industrialized arid countries, such as Iran. One of the main methods of mineral processing is flotation process that occurs in aquatic environments and consumes large volumes of water. The purpose of this paper was to investigate the use of sea water in the Cu-Mo ores froth flotation. In the experimental work, seawater was utilized as process water in the laboratory rougher flotation tests and compare the results with fresh water. The ore sample was porphyry Cu-Mo ore, which was delivered from Sarcheshmeh Copper complex. Results show that recovery of copper maintained almost the same level in both mediums. However, lime consumption was observed to be increased significantly under flotation conditions in seawater. In addition, the floatability of molybdenum was affected negatively above the pH 9.5-10. Recovery reduction of molybdenum was suggested to occur due to the magnesium hydroxide complexes and magnesium hydroxide precipitates, which began to form in seawater in higher pH levels. The experimental work showed that the conventional flotation of Cu-Mo ore conducted in seawater has serious conflicts, when pyrite is depressed with lime.