A Chicago scrap-iron refining company and its president pleaded guilty Wednesday to concealing more than $11 million in revenue from the IRS.

Acme Refining Co. and its president, 70-year-old Laurence C. Baron of Burr Ridge, each pleaded guilty to federal charges of impairing and impeding the Internal Revenue Service, according to the U.S. attorney’s office.

Sentencing will be Sept. 14 before U.S. District Judge Harry D. Leinenweber.

Baron and the company admitted they failed to report more than $11.6 million in wages paid to at least 50 employees between 2009 and 2013 and failed to withhold taxes from those wages.

Baron also admitted that he filed false tax returns in 2011 and 2012, causing a loss of about $208,875 in federal and state tax revenue, according to prosecutors.

Under a plea agreement, Baron must pay the IRS $1,333,084 in restitution while Acme must pay $4,545,243, the U.S. attorney’s office said.

Baron also pleaded guilty to a separate charge of willfully filing a false income tax return.