It wasn't selling uranium, it was selling a controlling stake in a uranium mining company. There's a difference between owning part of production so you may profit from it and buying the material itself. If you bought shares of Verizon, that doesn't mean you're spending that money on Verizon minutes.
Also, Russia produces its own uranium, as does Iran. The uranium Iran uses in its nuclear program is its own. They do not need the US as a source.
Funny you find Russia a hostile power on a mining issue. Are they still a hostile power when Trumo Inc is funded by its banks, makes real estate deals with them yet denying it, holds secret meetings with Putin, locks away or destroys transcripts from the translator at said meetings, is quick to support Russia's lies and wants while dismissing our own intelligence agencies and best interests, and offers to turn over FBI transcripts of its investigation of Russian meddling to Russia for review as well as turn over American diplomats to Russia for interrogation?
btw, Russia is no pal of Iran. All those countries and regions ending with "stan" would still be part of Iran if it wasn't for Russia, basically all of Central Asia all the way to Uighurstan in China.
The Great Game, 1700s, Google.