The potash, salt and magnesium miner posted adjusted earnings before interest, tax, depreciation and amortisation (EBITDA) of 611 million euros ($675.46 million) for the three months to Dec. 31, compared with 39 million euros a year earlier.

This includes a one-time gain of 219 million euros from the waste disposal joint venture REKS' sale.

"2021 was a very successful year. We made the company more efficient, leaner and more profitable, as well as strategically realigning K+S," Chairman Burkhard Lohr said in a statement.

In February, the group had forecast a core profit of 1.6-1.9 billion euros for 2022.

"With the above-mentioned range, we would achieve the best results in our company's history. Even with a view to the war in Ukraine and the associated dynamics in sales prices and energy risks, we stand by this forecast," Lohr added.

Potash spot prices soared after Russia's invasion of Ukraine on concerns over global supply disruption of the key crop fertiliser.

Shares in K+S, which produces about one-tenth of the world's potash, have soared 12% since Feb. 24, when Russia invaded Ukraine.

The company announced a dividend of 0.20 euros per share.

The United States, European Union and other nations have reacted to Russia's war on Ukraine by imposing economic sanctions that might hamper the country's ability to sell potash and other fertilisers abroad.

With a share of roughly one-fifth of all global trade, Russia is the world's largest fertiliser exporter.

Analysts from Deutsche Bank have said they expect the majority of exports out of the region to virtually stop, which would create a "colossal shortfall in an already tight market".

($1=0.9046 euros)

(Reporting by David Latona and Bartosz Dabrowski in Gdansk; Editing by Milla Nissi and Rashmi Aich)