Selective depression of pyrite during sphalerite flotation by a novel green organic depressant in copper-activated mineral flotation system: Separation performance and mechanism - Juan Yang; Xiaolin Zhang; Guanfei Zhao; Xingyu Chen; Haiyang He; Ruizeng Liu; Dianwen Liu; Peilun Shen; Liuyang Dong (Minerals Engineering, 2026)