Integrated Resources Life Insurance Cos. announced the $64-million acquisition of Capitol Life Insurance Co. of Denver as part of a planned growth program . . . Kaiser Steel changed the date of its special meeting of preferred stockholders and its annual shareholders meeting to Oct. 30 in Denver . . . A Merrill Lynch subsidiary said it bought a 5.2% stake in Anderson, Clayton & Co. . . . Australia could become an exporter of platinum following the discovery of huge reserves of the precious metal in the Kakadu National Park by Broken Hill Proprietary Co., Australia's energy minister said . . . Laidlaw, Adams & Peck confirmed the sale of a controlling interest in the independent broker and investment banking and asset management firm to a group of investors headed by John D. Kuhns, a former investment banker at Salomon Bros.