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July 31 (Reuters) - Mosaic Co, North America's No.2 potash producer, reported a 42 percent slump in quarterly profit, as average realized prices of potash fell by more than a fourth.
The company also said Chief Executive Jim Prokopanko, who has been on leave since May to undergo surgery to treat cancer, will resume his duties on Aug. 4.
Mosaic, the world's largest producer of finished phosphate products, and fellow potash producers have faced sharply lower prices and profits since last summer's breakup of one of the world's biggest potash traders, Belarusian Potash Co.
However, the lower prices have lately rekindled demand.
"We have long said we expected to see volumes increase before prices, and that scenario is playing out as anticipated," Larry Stranghoener, Mosaic's interim CEO, said on Thursday.
"We expect demand to remain high throughout the year, and with low global pipeline inventory, prices should remain firm," said Stranghoener, who will retire at the end of 2014.
Mosaic said it sold 3.4 million tonnes of phosphate in the second quarter ended June 30 and 2.5 million tonnes of potash, hitting the high ends of its forecast for both minerals.
Average realized prices of Mosaic's key products, diammonium phosphate and muriate of potash, fell 2.5 percent to $465 per tonne and 27 percent to $267 per tonne, respectively.
Net earnings attributable to the company fell to $248.4 million, or 64 cents per share per share, in the quarter, from $429.8 million, or $1.01 per share, a year earlier.
Net sales fell 7 percent to $2.44 billion.
Mosaic's shares closed at $47.18 Wednesday on the New York Stock Exchange. (Reporting by Sayantani Ghosh in Bangalore; Editing by Savio D'Souza)