| Concentration of ore | | Unwanted rocks, sand and grit from the mineral ore are called gangue or matrix. These have to be removed so that the mineral ore is concentrated with higher percentage of metal. Ores are mined from deep within the earth's crust in the form of rocks. The minerals are embedded in these rocks. The rocks are first crushed into smaller pieces by crushers. Then they are ground to powder by ball mill and other processes so that powdered ore is obtained. Depending on the type of ore, hydraulic washing, froth floatation process, magnetic separation and chemical separation techniques are applied for concentrating an ore. | | i) Hydraulic washing: | | As the name suggests, hydraulic washing process is done by washing the ores with streams of water. If an ore is heavier or denser than the gangue, then the gangue particles are washed way with the stream. The heavier or denser ore particles remain behind and can be collected. Hydraulic washing is done for ores that have tin or lead, as they are found to be heavier than the gangue. |  | | Previous | Next |
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