Lithium production through String Technology

About the String Technology

• A set of porous fibres twisted into strings and engineered them to have a water-loving (hydrophilic) core and water-repelling surface.
• When one end is dipped in a salt-water solution, the water travels up the string because of capillary action.
• Then, the water evaporates quickly from the string’s surface. This leaves behind salt ions such as sodium and lithium.
• The water will continue to evaporate like this as the salts become increasingly concentrated, eventually forming sodium chloride and lithium chloride crystals.
• The strings don’t just concentrate the salts. Since lithium and sodium have different physical properties, they crystallise at different locations on the strings.
• Sodium, with its low solubility, crystallises on the lower part, while the highly soluble lithium salts crystallise near the top.

Current method of production

• A large majority of the lithium produced in the world is extracted from “brine reservoirs” located in salt flats.
• Conventional methods of extraction rely on a series of massive evaporation ponds that concentrate lithium from saltwater reservoirs, salt flats of underground aquifers. 
• This method of production can require hundreds of square kilometres, and it often takes months or even years to produce lithium that can be used in batteries.
• It is commercially viable in a few locations around the world.

Key facts about Lithium

• It is a soft, silvery-white metal that belongs to the alkali metals group, of the periodic table of the elements.
• Features
  • It has the lowest density of all metals.
  • It is the lightest of the solid elements. 
  • It reacts vigorously with water.
• Occurrence:  
  • It does not occur as a metal in nature but is found combined in small amounts in igneous rocks.
• Major Reserves: Its reserves are majorly concentrated in the lithium triangle in South America – Argentina, Bolivia & Chile, with 50% of the deposits concentrated in these regions. 

Q1) What is alkali metal?

The alkali metals are a group of chemical elements located in Group 1 of the periodic table. They are known for their highly reactive nature and are some of the most reactive elements in the periodic table.

Source: New ‘string’ technology could revolutionise lithium production