Ralston Purina said it completed the previously...

Ralston Purina said it completed the previously announced sale of substantially all of its soybean processing operations to Cargill . . . Marriott announced plans for a 1,500-room convention hotel in downtown San Francisco, with completion scheduled for 1988 . . . Delta Air Lines has completed the sale and lease-back of nine Boeing 727-232 aircraft that the carrier acquired in the mid-1970s . . . Hoover Universal said it completed the acquisition of four beverage-bottle plants from Tricoast Container of Los Angeles.