SECOND AMENDMENT TO REVOLVING CREDIT AND SECURITY AGREEMENT

Exhibit 10.2

SECOND AMENDMENT TO REVOLVING CREDIT AND SECURITY AGREEMENT

Second Amendment to Revolving Credit and Security Agreement, dated as of the 16th day of July, 2004, by and among IMCO Recycling Inc., a Delaware corporation (“IMCO”), IMCO Investment Company, a Delaware corporation (“IMCO Investment”), IMCO Management Partnership, L.P., a Texas limited partnership (“IMCO Management”), IMCO Energy Corp., a Delaware corporation (“IMCO Energy”), IMCO Recycling of Indiana Inc., a Delaware corporation (“IMCO Recycling of Indiana”), IMCO Indiana Partnership L.P., an Indiana limited partnership (“IMCO Indiana LP”), IMCO Recycling of Illinois Inc., an Illinois corporation (“IMCO Recycling of Illinois”), Pittsburg Aluminum, Inc., a Kansas corporation (“Pittsburg Aluminum”), Alchem Aluminum, Inc., a Delaware corporation (“Alchem”), IMCO Recycling of Michigan L.L.C., a Delaware limited liability company (“IMCO Recycling of Michigan”), IMSAMET, Inc., a Delaware corporation (“IMSAMET”), IMCO Recycling of Idaho Inc., a Delaware corporation (“IMCO Recycling of Idaho”), Rock Creek Aluminum, Inc., an Ohio corporation (“Rock Creek”), IMCO Recycling of Utah Inc., a Delaware corporation (“IMCO Recycling of Utah”), Alchem Aluminum Shelbyville Inc., a Delaware corporation (“Alchem Shelbyville”), Interamerican Zinc, Inc., a Delaware corporation (“Interamerican”), U.S. Zinc Corporation, a Delaware corporation (“U.S. Zinc”), Gulf Reduction Corporation, a Delaware corporation (“Gulf Reduction”), Midwest Zinc Corporation, a Delaware corporation (“Midwest Zinc”), MetalChem, Inc., a Pennsylvania corporation (“MetalChem”), Western Zinc Corporation, a California corporation (“Western Zinc”), U.S. Zinc Export Corporation, a Texas corporation (“U.S. Zinc Export”), IMCO Recycling of California, Inc., a Delaware corporation (“IMCO Recycling of California”), Indiana Aluminum Inc., an Indiana corporation (“Indiana Aluminum”), IMCO Recycling of Ohio Inc., a Delaware corporation (“IMCO Recycling of Ohio”), IMCO Recycling Services Company, a Delaware corporation (“IMCO Recycling Services”), IMCO Operations Services Company, a Delaware corporation (“IMCO Operations Services”) and IMCO International, Inc., a Delaware corporation (“IMCO International”) (IMCO, IMCO Investment, IMCO Management, IMCO Energy, IMCO Recycling of Indiana, IMCO Indiana LP, IMCO Recycling of Illinois, Pittsburg Aluminum, Alchem, IMCO Recycling of Michigan, IMSAMET, IMCO Recycling of Idaho, Rock Creek, IMCO Recycling of Utah, Alchem Shelbyville, Interamerican, U.S. Zinc, Gulf Reduction, Midwest Zinc, MetalChem, Western Zinc, U.S. Zinc Export, IMCO Recycling of California, Indiana Aluminum, IMCO Recycling of Ohio, IMCO Recycling Services, IMCO Operations Services and IMCO International are each a “Borrower”, and collectively the “Borrowers”), the financial institutions which are now or which hereafter become a party hereto (collectively, the “Lenders” and, individually, a “Lender”), PNC Bank, National Association, as administrative agent, syndication agent and collateral agent for the Lenders (in such capacity, the “Agent”), and JPMorgan Chase Bank, as documentation agent for the Lenders (in such capacity, the “Documentation Agent”) (the “Second Amendment”).

W I T N E S S E T H :

WHEREAS, the Borrowers, the Lenders, the Agent and the Documentation Agent are parties to that certain Revolving Credit and Security Agreement dated October 6, 2003, pursuant to which, among other things, the Lenders agreed to extend credit to the Borrowers in

an aggregate principal amount not to exceed One Hundred Twenty Million and 00/100 Dollars ($120,000,000.00); and

WHEREAS, such Revolving Credit and Security Agreement was amended by the terms of that certain First Amendment to Revolving Credit and Security Agreement dated to be effective May 26, 2004, by and among the Borrowers, the Lenders, the Agent and the Documentation Agent (the “First Amendment”) (the Revolving Credit and Security Agreement, as amended by the terms of the First Amendment, being referred to herein as the “Loan Agreement”); and

WHEREAS, the Borrowers desire to amend certain provisions of the Loan Agreement and the Lenders and the Agent desire to permit such amendments pursuant to the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the premises contained herein and other valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and intending to be legally bound hereby, the parties hereto agree as follows:

1. All capitalized terms used herein which are defined in the Loan Agreement shall have the same meaning herein as in the Loan Agreement unless the context clearly indicates otherwise.

2. Section 10.11 of the Loan Agreement is hereby deleted in its entirety and in its stead is inserted the following:

10.11 any change in any Borrower’s condition or affairs (financial or otherwise) which in Agent’s reasonable opinion has a Material Adverse Effect; provided, however, that this Section 10.11 shall not be applicable and the Agent and the Lenders shall have no rights under this Section 10.11 so long as (a) the Borrowers’ Undrawn Availability for any period of three (3) consecutive Business Days is not less than Five Million and 00/100 Dollars ($5,000,000.00), and (b) the Borrowers’ daily average Undrawn Availability for any calendar month is not less than or equal to Ten Million and 00/100 Dollars ($10,000,000.00).

3. The provisions of Section 2 of this Second Amendment shall not become effective until the Agent has received the following, each in form and substance acceptable to the Agent:

4. The Borrowers hereby reconfirm and reaffirm all representations and warranties, agreements and covenants made by and pursuant to the terms and conditions of

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the Loan Agreement, except as such representations and warranties, agreements and covenants may have heretofore been amended, modified or waived in writing in accordance with the Loan Agreement or as set forth in this Second Amendment or the exhibits attached hereto, and except any such representations or warranties made as of a specific date or time, which shall have been true and correct in all material respects as of such date or time.

5. The Borrowers acknowledge and agree that each and every document, instrument or agreement which at any time has secured payment of the Obligations including, but not limited to, (i) the Loan Agreement, (ii) the Guarantor Security Agreement, and (iii) the Blocked Account Agreement, continue to secure prompt payment when due of the Obligations.

6. The Borrowers hereby represent and warrant to the Lenders and the Agent that (i) the Borrowers have the legal power and authority to execute and deliver this Second Amendment; (ii) the officers of the Borrowers executing this Second Amendment have been duly authorized to execute and deliver the same and bind the Borrowers with respect to the provisions hereof; (iii) the execution and delivery hereof by the Borrowers and the performance and observance by the Borrowers of the provisions hereof and of the Loan Agreement and all documents executed or to be executed therewith, do not violate or conflict with the organizational documents of the Borrowers or any law applicable to the Borrowers or result in a breach of any provision of or constitute a default under any other agreement, instrument or document binding upon or enforceable against the Borrowers and (iv) this Second Amendment, the Loan Agreement and the documents executed or to be executed by the Borrowers in connection herewith or therewith constitute valid and binding obligations of the Borrowers in every respect, enforceable in accordance with their respective terms.

7. The Borrowers represent and warrant that (i) no Event of Default exists under the Loan Agreement, nor will any occur as a result of the execution and delivery of this Second Amendment or the performance or observance of any provision hereof; (ii) the Schedules attached to and made part of the Loan Agreement are true and correct as of the date hereof in all material respects and there are no material modifications or supplements thereto, except as attached hereto; and (iii) they presently have no claims or actions of any kind at law or in equity against the Lenders or the Agent arising out of or in any way relating to the Loan Agreement or the Other Documents.

8. Each reference to the Loan Agreement that is made in the Loan Agreement or any other document executed or to be executed in connection therewith shall hereafter be construed as a reference to the Loan Agreement as amended hereby.

9. Except as amended hereby, all of the terms and conditions of the Loan Agreement shall remain in full force and effect. This Second Amendment amends the Loan Agreement and is not a novation thereof.

10. This Second Amendment may be executed in any number of counterparts and by the different parties hereto on separate counterparts each of which, when so

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executed, shall be deemed an original, but all such counterparts shall constitute but one and the same instrument.

11. This Second Amendment shall be governed by, and shall be construed and enforced in accordance with, the Laws of the Commonwealth of Pennsylvania without regard to the conflicts of law principles thereof. The Borrowers hereby consent to the jurisdiction and venue of the Court of Common Pleas of Allegheny County, Pennsylvania and the United States District Court for the Western District of Pennsylvania with respect to any suit arising out of or mentioning this Second Amendment.

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IN WITNESS WHEREOF, and intending to be legally bound, the parties hereto, have caused this Second Amendment to be duly executed by their duly authorized officers on the day and year first above written.