SHANGHAI, Mar 22 (SMM) - South Korean steel giant POSCO has announced that it will invest $4 billion in a new lithium project in Argentina. The funds will be used for a salt field project called Salar de Hombre Muerto, located on the border between northern Salta province and Catamarca province. POSCO expects to initially produce 25,000 mt of lithium hydroxide, a key lithium product used in battery materials, at the salt field. Once the project is completed, the production of lithium hydroxide will reach 100,000 mt.