Fill in the blanks choosing appropriate word/ words from those given in the brackets : (gravity separation, magnetic separation, absence, presence, `CuFeS_2`, `Cu_2S`, froth flotation, aluminium, iron, smelting, pure, impure, mines, copper, silver, sulfide, zinc, chromium nickel, tin, blister copper, Cus, Fes, thermal, electrical, argentite or silver glance `(Ag_2S)`, cuprous oxide, cuprous sulfide.)
Sulfide ores are concentrated by ............. process.

Explanation

**Step-by-Step Text Solution:**

1. **Identify the type of ores:** The question specifically mentions "sulfide ores." Sulfide ores are a category of ores that contain sulfur in their composition.

2. **Determine the concentration process:** To concentrate sulfide ores, we need to identify the appropriate method. The common method used for concentrating sulfide ores is the froth flotation process.

3. **Explain the froth flotation process:** In the froth flotation process, a suspension of the powdered ore is created with water. Collectors (like pine oil) are added to enhance the non-wettability of the mineral particles. Froth stabilizers are also added to stabilize the froth formed during the process.

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