Crushing and Grinding

• Crushing machines physically reduce the size of the chunks of ore that come from the mine so that they emerge smaller than golf balls. Grinding machines reduce the ore to powder, and the ore is separated from fragments that contain no ore.
  
  

Smelting Furnaces

• Hot furnaces melt ores. Some furnaces produce heat by means of electricity. In these furnaces, the metal and the waste material called slag separate and leave the furnace by different openings. For sulfide ores, a special process changes sulfur dioxide to sulfuric acid, which becomes a useful byproduct instead of a pollutant.
  
  

Chemical Process

• Chemical methods assist in the refining process. For example, in the froth flotation process, copper is separated from copper sulfide ore, according to Mine-Engineer. Surfactants render the copper less soluble in water than the waste material is, thus facilitating the separation.
  
  

Electrolytic Process

• Electrolytic processes obtain such metals as copper in a reasonably pure form. Positive metal ions migrate to the negative terminal, and are deposited there.