APLICAÇÃO DO MODELO DO NÚCLEO NÃO REAGIDO À LIXIVIAÇÃO DA CALCOPIRITA PELO ÍON Fe+3
MODELLING CHALCOPYRITE LEACHING BY Fe+3 IONS WITH THE SHRINKING CORE MODEL
Porcaro, Rodrigo Rangel; Martins, Flávio Luiz; Leão, Versiane Albis
http://dx.doi.org/10.4322/2176-1523.0799
Tecnol. Metal. Mater. Min., vol.12, n1, p.43-49, 2015
Resumo
cobre, A lixiviação da calcopirita pelo íon férrico é um processo considerado lento e com baixa recuperação desentido, fato atribuído à passivação do mineral. Nessepureza, o presente trabalho investiga a cinética de lixiviação de uma amostra de calcopirita de elevadaagitação, utilizando sulfato férrico como oxidante. Os efeitos da temperatura, Eh e concentração de Fe3+ na extração de cobre foram avaliados. Os dados experimentais seguiram o modelo do núcleo não-reagido com controle por difusão na camada de cinzas e alta energia de ativação (103,9±6,5kJ/mol), provavelmente devido à não consideração do efeito da distribuição de tamanhos de partículas (PSD) nas equações cinéticas. A aplicação da hipótese do estado quasi-estacionário em sistemas líquido-sólido bem como o efeito da PSD na interpretação dos dados cinéticos são discutidos.
Palavras-chave
Calcopirita, Modelo do núcleo não-reagido, Energia de ativação.
Abstract
Chalcopyrite leaching by ferric iron is considered a slow process with low copper recovery; a phenomenon ascribed to the passivation of the mineral surface during leaching. Thus, the current study investigated the leaching kinetics of a high purity chalcopyrite sample in the presence of ferric sulfate as oxidant. The effects of the stirring rate, temperature, Eh and Fe3+ concentration on copper extraction were assessed. The leaching data could be described by the shirking core model (SCM) for particles of unchanging size and indicated diffusion in the ash layer as the rate-controlling step with a high activation energy (103.9±6.5kJ/mol); likely an outcome of neglecting the effect of particle size distribution (PSD) on the kinetics equations. Both the application of the quasi-steady-state assumption to solid-liquid systems and the effect of the particle size distribution on the interpretation of kinetics data are also discussed.
Keywords
Chalcopyrite, Shrinking core model, Activation energy.
Referências
1 Ciminelli VST. Hidrometalurgia. In: Fernandes FRC, Matos GMM, Castilhos ZC, Luz AB, editors. Tendências Tecnológicas Brasil 2015. Rio de Janeiro: CETEM; 2005. p. 157-174.
2 Cruz FLS, Oliveira VA, Guimarães D, Souza AD, Leão VA. High-temperature bioleaching of nickel sulfides: Thermodynamic and kinetic implications. Hydrometallurgy. 2010;105(1-2):103-109. http://dx.doi.org/10.1016/j.hydromet.2010.08.006.
3 Córdoba EM, Muñoz JA, Blázquez ML, González F, Ballester A. Leaching of chalcopyrite with ferric ion. Part I: General aspects. Hydrometallurgy. 2008;93(3-4):81-87. http://dx.doi.org/10.1016/j.hydromet.2008.04.015.
4 Hackl RP, Dreisinger DB, Peters E, King JA. Passivation of chalcopyrite during oxidative leaching in sulfate media. Hydrometallurgy. 1995;39(1–3):25-48. http://dx.doi.org/10.1016/0304-386X(95)00023-A.
5 Córdoba EM, Muñoz JA, Blázquez ML, González F, Ballester A. Leaching of chalcopyrite with ferric ion. Part II: Effect of redox potential. Hydrometallurgy. 2008;93(3-4):88-96. http://dx.doi.org/10.1016/j.hydromet.2008.04.016.
6 Gbor PK, Jia CQ. Critical evaluation of coupling particle size distribution with the shrinking core model. Chemical Engineering Science. 2004;59(10):1979-1987. http://dx.doi.org/10.1016/j.ces.2004.01.047.
7 Souza AD, Pina PS, Leão VA, Silva CA, Siqueira PF. The leaching kinetics of a zinc sulphide concentrate in acid ferric sulphate. Hydrometallurgy. 2007;89(1-2):72-81. http://dx.doi.org/10.1016/j.hydromet.2007.05.008.
8 Santos FMF, Pina PS, Porcaro R, Oliveira VA, Silva CA, Leão VA. The kinetics of zinc silicate leaching in sodium hydroxide. Hydrometallurgy. 2010;102(1-4):43-49. http://dx.doi.org/10.1016/j.hydromet.2010.01.010.
9 Souza AD, Pina PS, Lima EVO, Silva CA, Leão VA. Kinetics of sulphuric acid leaching of a zinc silicate calcine. Hydrometallurgy. 2007;89(3-4):337-345. http://dx.doi.org/10.1016/j.hydromet.2007.08.005.
10 Carneiro MFC, Leão VA. The role of sodium chloride on surface properties of chalcopyrite leached with ferric sulphate. Hydrometallurgy. 2007;87(3-4):73-82. http://dx.doi.org/10.1016/j.hydromet.2007.01.005.
11 Munoz PB, Miller JD, Wadsworth ME. Reaction mechanism for the acid ferric sulfate leaching of chalcopyrite. MTB. 1979;10(2):149-158. http://dx.doi.org/10.1007/BF02652458.
12 Dutrizac JE, MacDonald RJC, Ingraham TR. The kinetics of dissolution of synthetic chalcopyrite in aqueous acidic ferric sulfate solutions. Transactions of the Metallurgical Society of AIME. 1969;245:955-959.
13 Munoz PB, Miller JD, Wadsworth ME. Reaction mechanism for the acid ferric sulfate leaching of chalcopyrite. MTB. 1979;10(2):149-158. http://dx.doi.org/10.1007/BF02652458. [English.]
14 Hiroyoshi N, Miki H, Hirajima T, Tsunekawa M. Enhancement of chalcopyrite leaching by ferrous ions in acidic ferric sulfate solutions. Hydrometallurgy. 2001;60(3):185-197. http://dx.doi.org/10.1016/S0304-386X(00)00155-9.
15 Levenspiel O. Chemical reaction engineering. New York: John Wiley & Sons; 1962. 578 p.
16 Liddell KC. Shrinking core models in hydrometallurgy: What students are not being told about the pseudo-steady approximation. Hydrometallurgy. 2005;79(1-2):62-68. http://dx.doi.org/10.1016/j.hydromet.2003.07.011.
17 Bischoff KB. Further comments on the pseudo steady state approximation for moving boundary diffusion problems. Chemical Engineering Science. 1965;20(8):783-784. http://dx.doi.org/10.1016/0009-2509(65)80065-3.
18 Taylor PR, Matos M, Martins GP. Modeling of noncatalytic fluid-solid reactions: The quasi-steady state assumption. MTB. 1983;14(1):49-53. http://dx.doi.org/10.1007/BF02670868.
2 Cruz FLS, Oliveira VA, Guimarães D, Souza AD, Leão VA. High-temperature bioleaching of nickel sulfides: Thermodynamic and kinetic implications. Hydrometallurgy. 2010;105(1-2):103-109. http://dx.doi.org/10.1016/j.hydromet.2010.08.006.
3 Córdoba EM, Muñoz JA, Blázquez ML, González F, Ballester A. Leaching of chalcopyrite with ferric ion. Part I: General aspects. Hydrometallurgy. 2008;93(3-4):81-87. http://dx.doi.org/10.1016/j.hydromet.2008.04.015.
4 Hackl RP, Dreisinger DB, Peters E, King JA. Passivation of chalcopyrite during oxidative leaching in sulfate media. Hydrometallurgy. 1995;39(1–3):25-48. http://dx.doi.org/10.1016/0304-386X(95)00023-A.
5 Córdoba EM, Muñoz JA, Blázquez ML, González F, Ballester A. Leaching of chalcopyrite with ferric ion. Part II: Effect of redox potential. Hydrometallurgy. 2008;93(3-4):88-96. http://dx.doi.org/10.1016/j.hydromet.2008.04.016.
6 Gbor PK, Jia CQ. Critical evaluation of coupling particle size distribution with the shrinking core model. Chemical Engineering Science. 2004;59(10):1979-1987. http://dx.doi.org/10.1016/j.ces.2004.01.047.
7 Souza AD, Pina PS, Leão VA, Silva CA, Siqueira PF. The leaching kinetics of a zinc sulphide concentrate in acid ferric sulphate. Hydrometallurgy. 2007;89(1-2):72-81. http://dx.doi.org/10.1016/j.hydromet.2007.05.008.
8 Santos FMF, Pina PS, Porcaro R, Oliveira VA, Silva CA, Leão VA. The kinetics of zinc silicate leaching in sodium hydroxide. Hydrometallurgy. 2010;102(1-4):43-49. http://dx.doi.org/10.1016/j.hydromet.2010.01.010.
9 Souza AD, Pina PS, Lima EVO, Silva CA, Leão VA. Kinetics of sulphuric acid leaching of a zinc silicate calcine. Hydrometallurgy. 2007;89(3-4):337-345. http://dx.doi.org/10.1016/j.hydromet.2007.08.005.
10 Carneiro MFC, Leão VA. The role of sodium chloride on surface properties of chalcopyrite leached with ferric sulphate. Hydrometallurgy. 2007;87(3-4):73-82. http://dx.doi.org/10.1016/j.hydromet.2007.01.005.
11 Munoz PB, Miller JD, Wadsworth ME. Reaction mechanism for the acid ferric sulfate leaching of chalcopyrite. MTB. 1979;10(2):149-158. http://dx.doi.org/10.1007/BF02652458.
12 Dutrizac JE, MacDonald RJC, Ingraham TR. The kinetics of dissolution of synthetic chalcopyrite in aqueous acidic ferric sulfate solutions. Transactions of the Metallurgical Society of AIME. 1969;245:955-959.
13 Munoz PB, Miller JD, Wadsworth ME. Reaction mechanism for the acid ferric sulfate leaching of chalcopyrite. MTB. 1979;10(2):149-158. http://dx.doi.org/10.1007/BF02652458. [English.]
14 Hiroyoshi N, Miki H, Hirajima T, Tsunekawa M. Enhancement of chalcopyrite leaching by ferrous ions in acidic ferric sulfate solutions. Hydrometallurgy. 2001;60(3):185-197. http://dx.doi.org/10.1016/S0304-386X(00)00155-9.
15 Levenspiel O. Chemical reaction engineering. New York: John Wiley & Sons; 1962. 578 p.
16 Liddell KC. Shrinking core models in hydrometallurgy: What students are not being told about the pseudo-steady approximation. Hydrometallurgy. 2005;79(1-2):62-68. http://dx.doi.org/10.1016/j.hydromet.2003.07.011.
17 Bischoff KB. Further comments on the pseudo steady state approximation for moving boundary diffusion problems. Chemical Engineering Science. 1965;20(8):783-784. http://dx.doi.org/10.1016/0009-2509(65)80065-3.
18 Taylor PR, Matos M, Martins GP. Modeling of noncatalytic fluid-solid reactions: The quasi-steady state assumption. MTB. 1983;14(1):49-53. http://dx.doi.org/10.1007/BF02670868.
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