A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp de...A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp density with less than 10% loss of productivity, and resist arsenic up to 15 g/L. There were a lot of jarosite, arsenolite and sulfur, but not scorodite and ferric arsenate in the bioleached residue. Jarosite passivation and lower sulfur-oxidizing activity of the cells due to the toxicity of the high concentrations of soluble arsenic and iron ions at low p H value should mainly response for the incomplete extraction at high pulp density. The initial bacterial community did not change in nature except for new found P aeruginosa ANSC, but sulfur-oxidizing microorganisms have been dominant microorganisms after a long time of adaptation. Pseudomonas aeruginosa originating from the gold concentrate should be closely relative to the metabolism of the organic matters contained in the refractory gold concentrate.展开更多
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-le...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.展开更多
高盐矿区往往缺乏淡水资源供生产使用。针对矿区盐水现状,进行高砷难处理金精矿生物氧化-氰化提金试验,考查不同氯离子浓度对硫化物氧化率、金浸出率等技术指标的影响。结果表明,氯离子浓度对金精矿生物氧化的不利影响随着浓度的升高而...高盐矿区往往缺乏淡水资源供生产使用。针对矿区盐水现状,进行高砷难处理金精矿生物氧化-氰化提金试验,考查不同氯离子浓度对硫化物氧化率、金浸出率等技术指标的影响。结果表明,氯离子浓度对金精矿生物氧化的不利影响随着浓度的升高而增强,氯离子浓度1.5 g L以上时,硫化物的氧化率显著降低,10 g L氯离子盐水生物氧化延长至18 d,砷浸出率88.4%,硫氧化率仅为35.3%。相同生物氧化渣在相同氰化条件下采用清水和10 g L氯离子盐水进行氰化浸出时,盐水将降低金的浸出率。1.5 g L、5 g L氯离子盐水生物氧化10 d后的氧化渣采用10 g L氯离子盐水氰化,金的浸出率分别比清水氰化时的分别低2.8、3.4个百分点。难处理金精矿生物氧化砷浸出率均高于硫氧化率,表明毒砂氧化率高于黄铁矿,金浸出率与毒砂氧化率的相关性较黄铁矿氧化率更加密切。展开更多
基金Project(2010CB630903)supported by the National Basic Research Program of ChinaProject(31200382)supported by the Chinese Science Foundation for Distinguished Group,China
文摘A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp density with less than 10% loss of productivity, and resist arsenic up to 15 g/L. There were a lot of jarosite, arsenolite and sulfur, but not scorodite and ferric arsenate in the bioleached residue. Jarosite passivation and lower sulfur-oxidizing activity of the cells due to the toxicity of the high concentrations of soluble arsenic and iron ions at low p H value should mainly response for the incomplete extraction at high pulp density. The initial bacterial community did not change in nature except for new found P aeruginosa ANSC, but sulfur-oxidizing microorganisms have been dominant microorganisms after a long time of adaptation. Pseudomonas aeruginosa originating from the gold concentrate should be closely relative to the metabolism of the organic matters contained in the refractory gold concentrate.
文摘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.
文摘高盐矿区往往缺乏淡水资源供生产使用。针对矿区盐水现状,进行高砷难处理金精矿生物氧化-氰化提金试验,考查不同氯离子浓度对硫化物氧化率、金浸出率等技术指标的影响。结果表明,氯离子浓度对金精矿生物氧化的不利影响随着浓度的升高而增强,氯离子浓度1.5 g L以上时,硫化物的氧化率显著降低,10 g L氯离子盐水生物氧化延长至18 d,砷浸出率88.4%,硫氧化率仅为35.3%。相同生物氧化渣在相同氰化条件下采用清水和10 g L氯离子盐水进行氰化浸出时,盐水将降低金的浸出率。1.5 g L、5 g L氯离子盐水生物氧化10 d后的氧化渣采用10 g L氯离子盐水氰化,金的浸出率分别比清水氰化时的分别低2.8、3.4个百分点。难处理金精矿生物氧化砷浸出率均高于硫氧化率,表明毒砂氧化率高于黄铁矿,金浸出率与毒砂氧化率的相关性较黄铁矿氧化率更加密切。
