At what PH should the acid leaching of uranium should be done?

what are the possible results concerning ph, what's the appropriate ph that acid leach of uranium should be done at?

Tagging @Ramani Aswath sir. 

My impression was that uranium is leached using carbonates and bicarbonates. Google scholar does show some acid leaching processes. Probably depends on the end use.

https://scholar.google.co.in/scholar?hl=en&as_sdt=0%2C5&q=acid+leaching+of+uranium+&btnG=