Resources from ally city states

[Indypapa]

I am way ahead of everyone on research. I researched electricity so I revealed aluminum. In a couple of city states that are allies a hill with a mine changed to a hill with aluminum with a mine, but I am not getting the aluminum resource. Are there other requirements to get strategic resources from allied city states?

 

[GWashington]

I don't think city-states get resources revealed until half the civilizations have discovered the tech for it, but you might be able to pay 200 gold for them to improve it.

 

[joncnunn]

Basically if you chronically have a 30+ turn wait waiting for city states to be granted the tech, it's a strong sign its time to move up a difficulty level.

In the mean time, just be patient. While this often does delay Hydro Plant construction, if you aren't going space race there's nothing that requires it; and even if you are, chances are very high they'll be granted it before you would need to build recycling centers.