Brazil's government is cautious about entering a rare earths partnership.
The U.S. seeks to strengthen ties in the critical minerals sector.
Economic and environmental factors are influencing Brazil's decision.
Strategic angle: Concerns arise as Brazil weighs the implications of a rare earths partnership with the U.S.
Brazil's government is cautious about entering a rare earths partnership.
The U.S. seeks to strengthen ties in the critical minerals sector.
Economic and environmental factors are influencing Brazil's decision.