The "portal-thingie" is a circular goblin-looking platform similar to ones in such places as Bootie Bay and Gadgetzan, or the Christmas "Santa's Helpers" transformers.  It has a blue glow emanating upward which should help you identify it.

You collect the dust, and yes, you have to run (at a reduced rate) to the turn-in site.  You might consider having someone with you to fight mobs that you aggro while you run onward.  If you remove the buff, the sands will linger for you to pick back up, but only for a short while.  It might disappear before you are able to kill the mob and pick the sands back up to continue.

And yes, you can do this turn-in without any quest.