Place the salt block over a low gas flame and heat for 10 minutes.
Raise the flame to medium and heat another 10 minutes.
Raise the flame to high and heat for an additional 15 minutes, until it is uncomfortable to hold your hand about 2 inches from the surface of the block for longer than 3 seconds (approximately 500°F).
While the salt block is heating pat the scallops completely dry.
Coat the scallops with the melted coconut oil and pepper and let stand at room temperature until the salt block is hot.
Place the scallops on the hot block.
The scallops should almost skitter across the top.
Sear until browned and springy to the touch but still a little soft in the center, 2 to 3 minutes per side.
Work in batches until all the scallops are cooked.
Remove to plates.
Scatter the lime zest over top and drizzle with the juice.