Yes. That was in S4. I don't recall the episode, I think it was the one where Chloe was strapped down and about to have her brain zapped. Lois was involved somewhere. Much of S4 is a blur. *makes a face at it*

But yes, if I recall correctly, Clark knocked a shelf into some kryptonite. I think the audience was supposed to infer that the GreenK had been knocked out of range, and was no longer harmful to him. The only problem with this is that the range where GreenK becomes actively harmful to him changes all the time, so that scene wound up being a little too convenient.