Make High Temperature Stove, Oven or Kiln | Want to Buy | Forum

Those electric pottery kilns reach temps you require. Anything rated "cone 11" or above will exceed 2400 degrees (fahrenheit). You could probably buy one off the shelf today and start your smelt tonight. 

You could also buy a "raku" kiln, which is usually a propane-powered kiln that reaches very high temperatures and seems like what you are needing. These are essentially the same thing as our forges and casting furnaces. 

Most blacksmiths can make these furnaces too, though most of us don't have need of thermostats and timers. We often just adjust the gas jet until we have the temperature required and leave it at that. 

A good cheap alternative for refractory is a $5 bag of pearlite from the garden section of your local hardware store and a pint of furnace cement from the ... uh, furnace cement section of your local hardware store. Woodstove/fireplace shops have it too. If nothing else, the section that has caulk often has fireplace caulk. 

Water the caulk/cement/mortar down until it's quite runny, pour it over the pearlite and stir it until the pearlite is evenly coated. Should be a consistency similar to rice crispy treats before they go in the pan. The cement is not the refractory - it's what holds the refractory (pearlite) together, so it should be barely enough to coat the pearlite. Any more is waste, and also a potential haven for trapped air & water. 

Let it dry for a week or so, and when you warm it up, do so very very slowly. I like to put burning charcoal in there and just let it slowly bake out the moisture and trapped air for a cycle before actually turning on the gas jets. No forced air or anything - simple BBQ temps for however long a bucket of coal lasts.