Ferro-Nickel Smelting at Oheyama Nickel Co., Ltd

Abstract

This company was founded in 1942 as Oheyama Plant of Nippon Yakin Kogyo Co., Ltd. to produce ferro-nickel from low grade nickel oxide ores of Mt. Oheyama. The smelting method at that time was something like the one known as the Krupp-Renn process, and operation continued till the end of World War II.
The plant began to run again in 1952, switching to imported ores from New Caledonia for its raw materials. The Krupp-Renn process, which we employed for treatment of nickel ores, has been modified and developed remarkably since then. Our engineering experiences and techniques stored over many years enabled us to achieve technical innovation and reformation in whole process, such as grinding and homogenization of materials, filtration, pelletizing, preheating, kiln- operation and jigging. We have now established a unique process for Fe-Ni smelting, which might be named “Nippon Yakin-Oheyama Process”.
In 1975 Oheyama Nickel Co. separated from Nippon Yakin Kogyo Co. Now monthly nickel production amounts to some 900 tons, and almost all of the products is sold to Nippon Yakin Kogyo Co. for stainless steel production.
Nippon Yakin-Oheyama Process has drawn attention to its low production cost, which is due essentially to its low consumption of expensive electricity and motive power use. The oxide ores within the rotary kiln are roasted and reduced by both fuel oil and coal. In the partially fused slae, the reduced metal particles then coalesce and grow to size of 0.5 to 30mm, which is called “Luppe”. Chemical analysis in percent; C<0.1, Si<0.1, Ni-18-22, slag<2.
Owing to its properties “Luppe” is also usef ul as coolant source for AOD process which is most important in stainless steel making.