Mercury impact on bioleaching microbial populations in laboratory and industrial like environments
During the last three years, concentrated sulfuric acid has become an important factor influencing the production cost of base metals. This reagent is used in hydrometallurgical processes, including chemical and biological-catalyzed leaching as well as in solvent extraction. Actually, the sulfuric acid market offers alternative qualities of concentrated sulfuric acid-some of them bearing mercury among other impurities. The goal of this work was to assess the effect of mercury on the microbial populations and on the copper dissolution during bioleaching of low grade copper sulfide ore. Previous studies showed the effect of mercury on acidophilic laboratory cultures. Our work studied the effect on indigenous microbial communities tested in industrial solutions and it compared those results with the ones obtained with isolated strains in culture media. Iron and sulfur oxidation tests were performed in flasks amended with different concentration of Hg2 + (0. 2, 0. 5 and 5 ppm) in order to study the oxidizing kinetics, the culture growth, the precipitates composition and the Hg volatilization. In addition, one meter columns leaching tests were used to compare the effect of the use of Hg-amended sulfuric acid to the use of normal sulfuric acid in copper bioleaching of low grade copper sulfide ore. The results indicated that the profile of Hg in culture media was significantly different to the observed one in industrial solutions, and some other differences were also observed when ferrous iron or sulfur were used as substrates. These differences are attributed to the reactivity of Hg + with Fe + , with S and with the sulfur-reduced compounds under different chemical conditions, in combination with the microbial oxidation/reduction. The volatilization of mercury was evident in industrial solutions and, clearly it is highly dependent on the microbial activity. The column test indicated a similar copper recovery when bioleaching proceeded in the presence of mercury. New insights into how the presence of mercury influences the bioleaching of low grade copper ore and the potential environmental impactare being discussed.
mercury inhibition mercury volatilization bioleaching sulfuric acid
Yasna Contador Karen S(a)ez Pedro Galleguillos Cecilia Demergasso
Centra de Biotecnologfa Profesor Alberto Ruiz, Universidad Catolica del Norte.Angamos0610, 124000 Centra de Biotecnologfa Profesor Alberto Ruiz, Universidad Catolica del Norte.Angamos0610, 124000
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
706-711
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）