Answer: b) Hematite
The gravity separation technique is used to concentrate ore, as we all know. The gravity separation method is based on the gravity differences between the ore and the gangue particles in the ore.
- Metal ores are, on average, heavier than gangue particles. This feature is used in the gravity separation process to concentrate ore.
- The gravity separation technique is used to concentrate hematite ore. Iron oxide ore hematite is a common resource.
- Fe2O3 is the chemical formula for hematite.
- The ore of hematite is black or silver-grey in colour. The hematite ore particles are first crushed to a fine powder, then concentrated via gravity separation.
- The powdered hematite ore is washed by an upward stream of flowing water during the gravity separation process. The lighter gangue particles are washed away by water. The ore particles that are heavier are left behind.