Abstract: Nickel ion contained in a ferric chloride waste liquid is recovered as metallic nickel by the following method. Firstly, the ferric chloride waste liquid is added with metallic iron and then heated and stirred to precipitate the metallic nickel. Thereafter the sludge containing this metallic nickel precipitate and the suspension are separated. Then, after the ferric chloride waste liquid is poured into the sludge and then heated and stirred so as to dissolve an iron constituent of the sludge and react it with the ferric chloride waste liquid, the suspension and the sludge are separated. After that, the sludge after the concentration process is taken out.

Abstract: A high strength stainless steel having the composition in % by weight of C: not more than 0.04%, N: 0.04-0.20%, Si: not more than 1.0%, Mn: not more than 2.0%, Ni: 6.0-10.0%, Cr: 16.0-20.0% and balance Fe and impurities inevitably incidental from the steelmaking process, and that the composition is adjusted to have an A.gamma. value of 19-21, where: A.gamma.=(%Ni)+0.60 (%Cr)+0.7 (%Mn)+13 [(%C)+(%N)], is disclosed. The steel exhibit excellent intergranular corrosion cracking resistance and workability as well as high strength.