Most manufacturing jewelers buy pure gold in shot form. That way, they can simply weigh out exactly the amount they need to make up karat alloys.
One place I worked was making silver shot in 1000-2000 oz batches. They used a fairly large gas fired standard crucible furnace elevated on a platform. There was a hole in the bottom of the furnace and the crucible was luted into the hole. Holes were drilled in the bottom of the crucible. I'm thinking that the holes were drilled with a #56 bit but they could have been a little larger, maybe a #53 or #54.
The stainless catch tank, about 50 gallons, on wheels, was moved into position under the furnace. There was about a 300 gal reservoir that continually provided cool water to the catch tank. The water was pumped into the bottom on the catch tank, at an angle, and there was an overflow near the top where the hot water returned to the reservoir. A large stainless small-holed colander, suspended by heavy wires, was placed near the bottom of the catch tank to catch the shot and make it easier to remove.
For making tiny karat gold shot for dissolving purposes, I once carved about a 3"-4" hardwood prop, drilled a hole in the middle, mounted it with nuts and washers on a length of threaded rod, and chucked in in a drill. I put the prop several inches deep in the water in a stainless container and poured the molten gold directly into the rotating prop. It wasn't as small as atomization would be, but it was the smallest I've ever seen from pouring into water.