The rotary kiln and electric furnace process has long been the most commonly employed method of recovering nickel from saprolitic laterite ores. Production improvements have been achieved over the years by the adoption of “shielded arc” smelting and the installation of water-cooled copper cooling elements in the furnace sidewalls. These pyrometallurgical processes are suited for ores containing predominately saprolite (1.5–3.0 percent nickel), with proportionately lower cobalt and iron content than limonitic ores. The nickel-cobalt ratio in the smelter feed is generally about 40. These ores are smelted to produce either ferronickel or matte.

The rotary reduction kilns are normally lined with CO-resistant castables that have sections of similarly CO-resistant brick. The electric ferronickel furnaces are designed with magnesia-and-tar-impregnated magnesia-based working linings. These are coupled with the installation of penetrative water-cooled copper elements in the furnace sidewalls and robust binding systems that provide long furnace life under intense smelting conditions. The final product can be produced by oxidation to a 75 percent FeNi using either Peirce-Smith or Kaldo rotary vessels lined with a combination of direct-bonded magnesia-chrome or rebonded fused-grain magnesia-chrome materials.