U.S. Treasury Secretary Janet Yellen on Saturday said she expects expanding demand for lithium to boost U.S. imports from Chile substantially in coming years.

A core goal of the U.S. Inflation Reduction Act is to reduce dependence on China, Yellen said, adding that the U.S. was keen to expand domestic production and find other sources of critical minerals like lithium needed to power electric vehicles.

"We want to certainly acquire minerals from our free trade partners, especially a country like Chile that is producing with great environmental sensitivity and has its own strong climate agenda," Yellen told reporters after a visit to a lithium conversion plant owned by U.S. firm Albemarle.

Yellen said increased purchases of lithium would likely increase U.S. imports from Chile and increase its share of Chilean exports. China is now Chile's biggest export market.

"I can't tell you numbers but I imagine that we will be expanding substantially our purchases from Chile, and we've been talking about that throughout the trip," she said.

(Reporting by Andrea Shalal; editing by Diane Craft)