摘要
During bio-oxidation of sulfides, the chemical state change of sulfur is a complex and key factor. It is not only an indicator of the extent and intensity of the bio-oxidation, but also controls the property of bio-leaching medium and the period of oxidation. The chemical state of sulfur in sulfides oxidized by leaching bacteria was studied with XPS. Sulfide minerals in the arsenic-bearing gold concentrate consist of pyrite, arsenopyrite, chalcopyrite, galena, sphalerite and so on. In order to probe the pattern of the chemical state change of sulfur in the bio-oxidation residue of arsenic-bearing gold concentrate, the structure of the grains, and the surface nature of the residue, XPS test was carried out through different sputtering duration. The study of XPS clearly shows that: sulfides is progressively oxidized from the surface of minerals to the core by leaching bacteria; the chemical valence of sulfur changes from S2- or [S2]2- to [SO4]2-; sulfur in the core is in a reduction state, S2- or [S2]2-, but exists in an oxidation state S6+ on the surface; due to the chemical state change of sulfur, mineral phase of the bio-oxidation residue is also changed（sulfides inside, while sulfates outside）; the layered structure is found in the grains of the bio-oxidation residue.
During bio-oxidation of sulfides, the chemical state change of sulfur is a complex and key factor. It is not only an indicator of the extent and intensity of the bio-oxidation, but also controls the property of bio-leaching medium and the period of oxidation. The chemical state of sulfur in sulfides oxidized by leaching bacteria was studied with XPS. Sulfide minerals in the arsenic-bearing gold concentrate consist of pyrite, arsenopyrite, chalcopyrite, galena, sphalerite and so on. In order to probe the pattern of the chemical state change of sulfur in the bio-oxidation residue of arsenic-bearing gold concentrate, the structure of the grains, and the surface nature of the residue, XPS test was carried out through different sputtering duration. The study of XPS clearly shows that: sulfides is progressively oxidized from the surface of minerals to the core by leaching bacteria; the chemical valence of sulfur changes from S^(2-) or [S_2]^(2-) to [SO_4]^(2-); sulfur in the core is in a reduction state, S^(2-) or [S_2]^(2-), but exists in an oxidation state S^(6+) on the surface; due to the chemical state change of sulfur, mineral phase of the bio-oxidation residue is also changed(sulfides inside, while sulfates outside); the layered structure is found in the grains of the bio-oxidation residue.
出处
《中国有色金属学会会刊：英文版》
CSCD
2004年第6期1187-1191,共5页
Transactions of Nonferrous Metals Society of China
基金
Projects( 5 0 0 740 15
5 0 2 740 2 4)supportedbytheNationalNaturalScienceFoundationofChina
project ( 2 0 0 2 2 0 2 2 )supportedbytheNaturalScienceFoundationofLiaoningProvince
关键词
XPS
表面性质
化学态
细菌氧化
晶体结构
冶金工艺
bio-oxidation
arsenic-bearing gold concentrate
XPS
chemical state
sulfur
surface nature
