Brine mining is the process of extracting useful materials, compounds or elements which are dissolved naturally in brine. What is Brine? Brine can be seawater, groundwater or any surface water. Brine mining is different from in-situ leaching or solution mining. The difference is that these other two processes of mining use the method of injecting chemicals or water to dissolve materials which are in a solid state. In the extraction of brine, the materials are readily dissolved.
Brine is a significant source of iodine, sodium chloride, magnesium, potassium, bromine, lithium, phosphate, soda ash, silica, sodium sulphate, gold, and other essential elements and materials.
Types of Brines Used in Extraction of Minerals
A brine mining company can use its brine in the extraction and mining of minerals and other chemical elements. There are certain types of brines used in the process of mining these elements. These types of brine are discussed below.
Seawater is known as the major source of sodium chloride since the prehistoric times. Not only is it a source of salt but also bromine and magnesium. Potassium too can be extracted from seawater when the salt is precipitated and left to dry.
2. Saline Lakes Brine
Lakes which are saline are useful in the extraction of minerals. Examples of these lakes include the Lake Natron in East Africa which is a significant source of Sodium Carbonate. Other lakes are the Great Salt Lake and the Dead Sea.
3. Shallow Groundwater Brines
Groundwater just beneath dry or saline lakes has brines with chemical properties similar to that of lakes. These brines are used in the extraction of minerals like sodium, potassium, and magnesium. Searles Lake in California is one example of shallow brines found in the United States.
4. Geothermal Brines
During operations of geothermal power plants, brine is always brought to the surface of the earth. The brine can be used in the extraction of minerals, and it’s a good source of zinc. At Larderello Italy, geothermal brine was used to extract Boron. Lithium has also been generated from geothermal brine without forgetting Silica which was recovered in Wairkei, New Zealand as well as Mammoth lakes in California.
5. Deep Sedimentary Brines
Total Dissolved Solids (TDS) are highly concentrated in deep connate water as compared to seawater because TDS concentrations increase with depth. Most of the deep sedimentary brines exist in the form of sodium chloride a highly ionic compound which is readily soluble in water. The total dissolved solids concentration is high for deep connate water because it comes into contact with salt beds. This type of brine uses the approach of ion exchange in the extraction of the minerals. The elements with is high in the reactivity series replace the less active cation in the sodium chloride compound. For example, potassium which is more reactive than sodium replaces the sodium and bounds with the chloride molecules to form potassium chloride. The compound is then extracted, and later it is separate into individual constituent elements.