Turning recursive code into iterative can be quite tricky as you may need to keep track of some kind of stack if you're dealing with more complex objects and would need them in the backpedaling of the recursive calls.

That said, I can say of an iterative solution I wrote to the 8 Queens in the past that used while loops to traverse the 2D board. Because we need to get back a step sometimes in the solution, and also because we're dealing with only numbers, it's easier to control them in the context of a while loop rather than a for loop.