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Smelting of Nickel Oxide Ores to Produce Ferronickel.
Hunter-WL; Paulson-DW; Stickney-WA
U S Pat 3 854 936 1974 Dec; :
Those ores of either the laterite or serpentine type and containing generally 1-2 pct ni with much more fe, are smelted in an arc furnace to a ferroalloy containing >40 pct ni by a new 2-step process using cheap coke reducing agent and lean ore, which is not concentrated, but merely pre-dried at 1,200 deg.-1,500 Deg. F in a rotary kiln. In the 1st smelting stage the hot ore coming from the drier is mixed with 35-40 pct of the coke required to reduce oxides of ni and fe, and the smelting is carried out at a temperature sufficiently high to convert the ore gangue to a fluid slag depleted in ni but not fe. The slag is removed, leaving a low-grade ni alloy in the furnace. Another charge is then added, of hot calcined ore with 20-25 pct of the coke required for reduction of its oxides of ni and fe, and this is smelted to add ni to the low-grade alloy in the product, and the 1st step is repeated with its greater proportion of reducing agent to reduce ni from the high-nio slag left in the furnace.
U.S. Pat. 3,854,936; Dec. 17, 1974; Chem. Abstr. 82:88,717R
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division