A federal appeals court threw out on Friday an antitrust class-action lawsuit accusing seven companies of engaging in a global conspiracy to raise the price of potash, a mineral used mainly in fertilizer.

The 7th Circuit Court of Appeals in Chicago said the plaintiffs, who were purchasers of potash, did not claim a sufficient link between alleged anti-competitive activity taking place outside the United States and the domestic potash market.

It voided a lower court's refusal to end the case, and directed that the purchasers' claims under the Sherman Act, a U.S. antitrust law, be dismissed.

The defendants included Canada's Agrium Inc and Potash Corp of Saskatchewan Inc
, Mosaic Co , and four companies that conduct mining operations in Russia and Belarus: JSC Uralkali, JSC Silvinit, JSC Belarusian Potash and JSC International Potash.

(Reporting by Jonathan Stempel in New York, editing by Gerald E. McCormick)