WASHINGTON, April 19 (Reuters) - K+S has won antitrust approval to sell its North and South American salt business, including Morton Salt, to Stone Canyon Industry Holdings LLC, the Justice Department said on Monday.

As condition of the approval for the $3.2 billion deal, Stone Canyon is required to sell its evaporated salt business, the department said.

"Without the divestiture, the proposed acquisition would substantially lessen competition in the sale of several types of evaporated salt, including round-can table salt, pharmaceutical-grade salt, and bulk evaporated salt," the department said.

Morton, which is owned by K+S, and US Salt, which is owned by Stone Canyon, are two of the three companies which make round-can table salt for the U.S. market and the only two companies which make pharmaceutical grade salt for the U.S. market which is needed for dialysis treatment and intravenous saline solutions, the department said.

The deal, which was announced in October, was seen as part of an effort by K+S to sell its debt and focus on potash fertilizer products. (Reporting by Diane Bartz Editing by Chizu Nomiyama)