BUENOS AIRES, May 20 (Reuters) - Dubai-based United Mining Projects Corporation (UMPC) plans to begin producing battery-grade lithium in Argentina next year, aiming to deliver 5,000 metric tons in 2027 and double that in 2028, CEO Bradley Pielsticker said in an interview.

Argentina is the world's fourth-largest lithium producer, with a pipeline of projects led by international companies set to ramp up in the coming months.

UMPC will operate in Argentina's Catamarca province through its subsidiary Marhen Lithium, and is currently analyzing its first production samples, Pielsticker said in the interview on Friday, after last month announcing a $550 million investment in the project.

The company is still determining which extraction method to use, but will likely begin with a mix of direct lithium extraction (DLE) and evaporation pools.

"We're looking at what steps we'll take with the pilot plant, which we expect to have operating next year," Pielsticker said. "We're looking at direct extraction to help us manage water resources more efficiently."

Argentina, weathering a prolonged economic crisis with a shortage of foreign currency, is betting on increased mining exports to boost the country's coffers. Lithium output grew nearly a third in 2023 compared to the prior year.

Pielsticker said he supports a proposal from President Javier Milei, under discussion in Congress, to give taxes, customs and exchange rate benefits to large projects.

"We are delighted with the general idea of changes that legislation could bring to mining projects," Pielsticker said. (Reporting by Lucila Sigal; Editing by Will Dunham)