SANTIAGO (Reuters) - More than 50 companies have expressed interest in developing lithium projects in Chile, Finance Minister Mario Marcel said on Tuesday, after the government called for proposals for a range of salt flats containing the battery metal.

The 54 firms from 10 countries submitted statements of interest to develop 88 projects through a public process that began in April and ended on Monday, Marcel said at an event in Santiago.

Chile is seeking to build its role in the lithium industry, which is the world's second largest after Australia, through state-led projects as well as private investment.

Officials in mid-April called for proposals for launching lithium projects in more than two dozen salt flats that have yet to be fully explored, while reserving the Atacama and Maricunga brine deposits for state control.

Investors raised concerns about how the government will award lithium contracts in salt flats where mining concessions have previously been granted, which risks creating a kind of double ownership.