What mixtures can be separated by leaching?

Question

Avery Adams · Accepted Answer

Solid mixtures a soluble component can be separated by leaching.

Leaching is the process of extracting substances from a solid mixture by dissolving them in a liquid.

Some examples of leaching are

Extraction of a metal from its ore
Low grade gold ore is spread in large piles or heaps in a lined pit. It is sprayed with a cyanide solution that percolates down through heap. Cyanide ion leaches gold from its ores by the reaction

Au + 2CN⁻ ⇌ Au(CN)₂⁻ + e⁻

The oxidizing agent (electron acceptor) is atmospheric oxygen.

O₂ + 2H₂O + 4e⁻ ⇌ 4OH⁻
- Extraction of sugar from beets
  Long thin beet strips travel up a slope against hot water flowing down. Sugar diffuses out of the beets. The hot solution at the bottom contains 10 % to 15 % sugar.
  - Extraction of natural oils
    Organic solvents such as hydrocarbons, acetone, and ether extract oils from nuts, beans, and seeds.
    - Extraction of pharmaceutical products
      Many different pharmaceutical products are obtained by leaching plant roots, leaves, and stems.

Xavier Avery · Answer

undefined Mixtures that can be separated by leaching include those where one component is soluble in a solvent while the other is insoluble or less soluble. This method is commonly used in the separation of ores from gangue materials in mining and metallurgy processes.