Investigation of the dissolution kinetics of kaolin in HCl solution

Altıokka, Mehmet Rıza; Hoşgün, Halit L.

doi:10.1016/s0304-386x(02)00193-7

Cited by 28 publications

(19 citation statements)

References 3 publications

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“…Terry (1983a and1983b) classified the silicates according to their reactivity with acids in the following way: those that are not readily decomposed by acids; those from which the cations, but not the silica, can be readily dissolved; and those from which the cations and silica are readily dissolved. Further researchers studied the dissolution of metakaolin using HCl (Hulbert et al, 1970, Altiokka et al, 2003, Bazin et al, 2007, HNO 3 (Hulbert et al, 1970) and H 2 SO 4 (Altiokka et al, 2010, Colina et al, 2002.…”

Section: Metalurgia E Materiaismentioning

confidence: 99%

Hydrometallurgical extraction of Al and Si from kaolinitic clays

et al. 2017

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Herein is presented the results of a study on the hydrometallurgic extraction and recovery of aluminum and silicon by leaching of kaolinitic clays with HF. The studied extraction parameters were: temperature, reaction time, solid/liquid ratio, concentration, and precipitating agent mass. In the leaching process, mineral dissolutions near 100% were obtained when working at 348 K, solid/liquid ratio 2% w/v, HF 12% v/v, for 120 minutes. The HF leach liquor generated from the dissolution of kaolinitic clays contains H 2 SiF 6 and H 3 AlF 6 . Studies were conducted to recover the two valuable fluorides as K 2 SiF 6 and Na 3 AlF 6 by precipitation with alkaline salts from the leach liquor. Phases of precipitated fluorides were identified by XRD and surface morphology by SEM. The purity of the K 2 SiF 6 precipitate was 98.8%, whereas for Na 3 AlF 6 , it was 89.3%. Also, both synthesized solids are of high commercial value due to their industrial applications.

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Section: Metalurgia E Materiaismentioning

confidence: 99%

Hydrometallurgical extraction of Al and Si from kaolinitic clays

et al. 2017

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“…Gajam & Raghavan (1985) developed a kinetic model for hydrochloric acid leaching of a kaolinite clay in the presence of fluoride ions. Altiokka & Hosģün (2003) discussed the kinetics of dissolution of Al, using HCl, from the calcined kaolin. Ajemba & Onukwuli (2012) applied a kinetic model to a clay-dissolution (in HCl) process.…”

Section: Kaolinmentioning

confidence: 99%

“…The latter authors found an activation energy of 71 kJ/mol for calcined material without the presence of fluoride ions. Altiokka & Hosģün (2003) investigated the dissolution kinetics of calcined kaolin in HCl. The kaolin was obtained from Sigma Chemical Co and the experiments were performed with excess acid >90%.…”

Section: Kinetic Studymentioning

confidence: 99%

Dissolution kinetics of Amazonian metakaolin in hydrochloric acid

2017

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The kinetics of dissolution of Amazonian metakaolin in hydrochloric acid (HCl) was studied using the ‘Shrinking Core Model’ for spherical and ‘flat plate’ particles of constant size. The Amazonian kaolin was calcined at 700°C for 2 h. The calcined samples (metakaolins) were leached in an HCl solution with 5% excess at 70, 80 and 95 ± 3°C for 3 h. Samples were collected every 15 min and subjected to Al analysis by the EDTA titrimetric method. Experimental data showed that the spherical morphology produced a better fit with respect to the regression coefficients. The activation energy of the reaction was 90.6 kJ/mol. The chemical process is a first-order leaching reaction. The results of the present study are consistent with those from previous research on this topic, which used HCl with an excess of >90%.

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“…Em 1992 foi estudada a lixiviação de um caulim oriundo da África com ácido sulfúrico [7]. Em 2003 foi investigada a cinética de dissolução do caulim com ácido clorídrico [11]. Em 2010 foi estudada a cinética de dissolução do metacaulim com ácido sulfúrico, dentre outros [12].…”

Section: Introductionunclassified

Investigação da reatividade e da cinética de dissolução do metacaulim em ácido sulfúrico

et al. 2013

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Um estudo da reatividade e da cinética de dissolução do metacaulim foi desenvolvido para o caulim de cobertura de papel oriundo da região do Rio Capim, Pará. O caulim foi calcinado a 600, 700, 800, 900 e 1000 ºC por 2 h para obtenção do metacaulim e posteriormente lixiviado com ácido sulfúrico em temperaturas constantes dentro do intervalo 50-95 °C ± 3 °C. Nas lixiviações foram usadas quantidades de ácido sulfúrico correspondentes a 10% acima do valor estequiométrico em relação ao alumínio presente no material. Foram coletadas amostras, com intervalos pré-determinados a cada 15 min até tempo total de 3 h, as quais foram submetidas à análise de teor de alumínio pelo método titrimétrico com EDTA. Os resultados mostraram que a reatividade do caulim calcinado diminuiu com o aumento da temperatura de calcinação e que a cinética de dissolução do alumínio do metacaulim obtido por calcinação a 700 °C seguiu os métodos de reação homogênea utilizados: método integral, método das meia-vidas e método das velocidades iniciais. Uma energia de ativação de 96,25 kJ/mol foi encontrada bem como reação de lixiviação de primeira ordem em relação ao alumínio do metacaulim e de primeira ordem em relação à concentração ácida. Pesquisas realizadas anteriormente, utilizando excesso de um dos reagentes acima de 90% e modelos de reação heterogênea, estão em consonância com os dados encontrados neste trabalho desenvolvido com excesso de apenas 10%.

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Investigation of the dissolution kinetics of kaolin in HCl solution

Cited by 28 publications

References 3 publications

Hydrometallurgical extraction of Al and Si from kaolinitic clays

Hydrometallurgical extraction of Al and Si from kaolinitic clays

Dissolution kinetics of Amazonian metakaolin in hydrochloric acid

Investigação da reatividade e da cinética de dissolução do metacaulim em ácido sulfúrico

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