"The copper mineral is recovered and concentrated by a process called flotation. In flotation, the finely ground ore is mixed with water to from a slurry. Certain chemicals or reagents that coat only the desired copper minerals are added in small amounts. Rising air bubbles capture the coated mineral particles and float them to the surface where they are skimmed off and dried. This dried material is called copper concentrate and is approximately 30 percent copper, 27 percent iron and 33 percent sulfur. The waste rock, now called tailings remain in the slurry." Arizona Mining Association.
The waste material, called gangue, sinks to the bottom of the flotation tanks and is removed.
From here, the "powdered enriched ore is heated in air between 500 °C and 700 °C to remove some sulphur and dry the ore, which is still a solid called calcine." Copper Mining.