Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER

AND CHIEF FINANCIAL OFFICER

PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Aleris Corporation (the “Company”) on Form 10-K for the period ended December 31, 2019 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Sean M. Stack, Chairman and Chief Executive Officer of the Company, and Eric M. Rychel, Executive Vice President, Chief Financial Officer and Treasurer of the Company, each hereby certifies, pursuant to 18 U.S.C. § 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to his knowledge:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date:	March 18, 2020	/s/ Sean M. Stack
		Sean M. Stack
		Chairman and Chief Executive Officer (Principal Executive Officer)
Date:	March 18, 2020	/s/ Eric M. Rychel
		Eric M. Rychel
		Executive Vice President, Chief Financial Officer and Treasurer (Principal Financial Officer)