"nickel-containing stainless steel ash" refers to the nickel-bearing dust and ash by-products generated and captured during the stainless steel smelting, alloy production, or nickel resource utilization processes, particularly from flue gas purification, material collection, or processing operations. This type of nickel-containing stainless steel ash contains certain amounts of nickel, iron, chromium, and other alloying elements. After collection, dewatering, sorting, and metallurgical processing, it can be recycled as a resource for nickel and ferroalloys, and reused in stainless steel production or other metallurgical processes.