The Collaborative International Dictionary of English v.0.48:

Amalgamator \A*mal"ga*ma`tor\, n.
   One who, or that which, amalgamates. Specifically: A machine
   for separating precious metals from earthy particles by
   bringing them in contact with a body of mercury with which
   they form an amalgam.
   [1913 Webster]

WordNet (r) 3.0 (2006):

amalgamator
    n 1: a businessman who arranges an amalgamation of two or more
         commercial companies