Gangue facts for kids
Gangue (pronounced "gang") is the unwanted rock or mineral material that is mixed in with the valuable ore when miners dig it out of the ground. Think of it like finding a few chocolate chips in a big pile of plain cookie dough. The chocolate chips are the valuable ore, and the plain dough is the gangue.
Miners want to get rid of the gangue because it makes up most of the material they dig up. It's not useful and just adds weight and cost to transport and process the valuable minerals.
Contents
Why Separate Gangue?
When miners extract ore from the Earth, the valuable minerals are often only a small part of the rock. The rest is gangue. Separating the gangue from the ore is very important for several reasons. It makes the valuable mineral more concentrated, which means it's purer and easier to use. Removing gangue also reduces the amount of material that needs to be transported and processed. This saves a lot of money and energy.
How is Gangue Separated?
Miners use different methods to separate gangue from the valuable ore. One common method is called flotation. In this process, the ore is crushed into a fine powder and mixed with water and special chemicals. These chemicals make the valuable mineral particles float to the top, while the heavier gangue particles sink to the bottom. The floating mineral foam is then collected.
Other methods include:
- Gravity separation: This uses the difference in weight between the ore and the gangue. Heavier ore particles can be separated from lighter gangue particles using water or air.
- Magnetic separation: If the valuable mineral is magnetic and the gangue is not (or vice versa), magnets can be used to pull them apart.
- Hand sorting: Sometimes, especially in smaller operations, people can simply pick out the valuable ore from the gangue by hand.
Can Gangue Be Useful?
Even though gangue is usually considered worthless, sometimes it can be used later. For example, if the gangue contains another mineral that becomes valuable in the future, it might be processed again. Also, the leftover gangue material, often called "tailings," can sometimes be used in construction or as fill material. However, managing tailings safely is very important because they can sometimes contain harmful substances.
Images for kids
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This rock sample shows sphalerite (brown) and galena as the main ore minerals. The white material is calcite, which is the main gangue mineral. This sample is from an old mine in Germany.
See also
In Spanish: Ganga (minería) para niños
