Easton's 1897 Bible Dictionary:

Amraphel
   king of Shinar, southern Chaldea, one of the confederates of
   Chedorlaomer, king of Elam, in a war against Sodom and cities of
   the plain (Gen. 14:1, 4). It is now found that Amraphel (or
   Ammirapaltu) is the Khammu-rabi whose name appears on
   recently-discovered monuments. (See CHEDORLAOMER).
   After defeating Arioch (q.v.) he united Babylonia under one
   rule, and made Babylon his capital.


Hitchcock's Bible Names Dictionary (late 1800's):

Amraphel, one that speaks of secrets