Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates

The large-scale biooxidation of gold concentrates is usually carried on in continuous stirred tank reactors (CSTR). Attaining homogeneous slurries is a difficult task, as solids tend to stratify in the tank. The objective of this work was to determine the optimal conditions of agitation in a CSTR so...

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Autores principales: González,Ramón, Gentina,Juan C., Acevedo,Fernando
Lenguaje:English
Publicado: Pontificia Universidad Católica de Valparaíso 2003
Acceso en línea:http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582003000300008
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spelling oai:scielo:S0717-345820030003000082004-05-04Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentratesGonzález,RamónGentina,Juan C.Acevedo,Fernando The large-scale biooxidation of gold concentrates is usually carried on in continuous stirred tank reactors (CSTR). Attaining homogeneous slurries is a difficult task, as solids tend to stratify in the tank. The objective of this work was to determine the optimal conditions of agitation in a CSTR so to obtain the best solids suspension. The experiments were performed in a 5 litre glass tank operated with 3 litres of 6% w/v slurry. The impellers (pitched blade turbine or marine propeller) were placed at heights of 6.7 to 13.4 cm from the bottom and operated at 370 to 1040 rpm, with specific aeration rates of 0.3 to 3.7 vvm. A statistical experimental design was used which allowed the derivation of a model representing response surfaces of the exit and mean solids concentration as a function of the impeller type, impeller distance from the bottom and aeration and agitation rates. During the experiments no solids were deposited on the bottom and the solids concentration near the bottom was always higher than that of the top region. At the optimal conditions for each type of impeller, the marine propeller required agitation rates about 15 to 22% higher than the pitched blade turbine. Nevertheless it is concluded that the marine helix is preferable because it requires less power and produces a more homogeneous suspension.info:eu-repo/semantics/openAccessPontificia Universidad Católica de ValparaísoElectronic Journal of Biotechnology v.6 n.3 20032003-12-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582003000300008en
institution Scielo Chile
collection Scielo Chile
language English
description The large-scale biooxidation of gold concentrates is usually carried on in continuous stirred tank reactors (CSTR). Attaining homogeneous slurries is a difficult task, as solids tend to stratify in the tank. The objective of this work was to determine the optimal conditions of agitation in a CSTR so to obtain the best solids suspension. The experiments were performed in a 5 litre glass tank operated with 3 litres of 6% w/v slurry. The impellers (pitched blade turbine or marine propeller) were placed at heights of 6.7 to 13.4 cm from the bottom and operated at 370 to 1040 rpm, with specific aeration rates of 0.3 to 3.7 vvm. A statistical experimental design was used which allowed the derivation of a model representing response surfaces of the exit and mean solids concentration as a function of the impeller type, impeller distance from the bottom and aeration and agitation rates. During the experiments no solids were deposited on the bottom and the solids concentration near the bottom was always higher than that of the top region. At the optimal conditions for each type of impeller, the marine propeller required agitation rates about 15 to 22% higher than the pitched blade turbine. Nevertheless it is concluded that the marine helix is preferable because it requires less power and produces a more homogeneous suspension.
author González,Ramón
Gentina,Juan C.
Acevedo,Fernando
spellingShingle González,Ramón
Gentina,Juan C.
Acevedo,Fernando
Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
author_facet González,Ramón
Gentina,Juan C.
Acevedo,Fernando
author_sort González,Ramón
title Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
title_short Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
title_full Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
title_fullStr Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
title_full_unstemmed Optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
title_sort optimisation of the solids suspension conditions in a continuous stirred tank reactor for the biooxidation of refractory gold concentrates
publisher Pontificia Universidad Católica de Valparaíso
publishDate 2003
url http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582003000300008
work_keys_str_mv AT gonzalezramon optimisationofthesolidssuspensionconditionsinacontinuousstirredtankreactorforthebiooxidationofrefractorygoldconcentrates
AT gentinajuanc optimisationofthesolidssuspensionconditionsinacontinuousstirredtankreactorforthebiooxidationofrefractorygoldconcentrates
AT acevedofernando optimisationofthesolidssuspensionconditionsinacontinuousstirredtankreactorforthebiooxidationofrefractorygoldconcentrates
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