What Is Involved in Lithium Production?
Lithium is a soft, alkali metallic element produced from salts extracted from mineral springs and naturally-occurring brine deposits. A large proportion of the world's lithium production is achieved using a fairly simple natural process of concentration of lithium salt laden solutions followed by evaporation and refinement. The refinement process typically produces lithium carbonate and lithium hydroxide in granulated form. The solid, metallic presentation of the element is produced by a process of electrolysis involving the fusion of lithium chloride and potassium chloride. Notwithstanding its highly unstable elemental nature, lithium production generates compounds with many practical uses, including components in automotive batteries, lubricants, and pharmaceutical preparations.
The light gray chunks often seen floating in a beaker of oil in a school laboratory are the metallic form of lithium. Lithium, in this format at least, exhibits the highly unstable and flammable nature typical of all alkali metals, hence the need to store it in oil. It is, however, very useful in other forms and is used as a component in a wide range of products. Lithium does not occur freely in nature in its elemental form and occurs in ionic compounds found in a range of pegmatitic minerals. These include the waters of mineral springs and the ocean, as well as natural brine and clay deposits.
One of the most prolific of these natural sources are salt flats, with Chile and Argentina being among the world's largest producers of the element. The nature of these sources means that the initial stage of lithium production is a simple process of concentration and evaporation. This takes place in large brine concentration ponds where the overall concentration of suspended lithium is allowed to rise to approximately six percent through evaporation of water from the suspension. Once the required concentration is reached, the brine is pumped to plants producing lithium carbonate and hydroxide end products. In most processes, potassium ponds are co-located with the brine ponds with the manufacture of potassium chloride being carried out in parallel to lithium production.
The lithium carbonate and hydroxide is then distributed for use in a wide range of industrial and medical applications. These include the manufacture of automotive batteries, high grade lubricants such as lithium grease, and several pharmaceutical products including mood-altering drugs used to treat depression and schizo-affective disorders. They are also used in the production of ceramic and glass products, air purification components, and electronic components. The highly unstable elemental metallic form of lithium found in most laboratories is produced through an electrolytic process where lithium and potassium chlorides are fused and not through conventional lithium production.
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