Skip to main content Accessibility help
×
Home
Hostname: page-component-78bd46657c-4dqq5 Total loading time: 0.192 Render date: 2021-05-06T14:03:04.535Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": false, "newCiteModal": false, "newCitedByModal": true }

An investigation of the nature and reducibility of Ni-hydroxy-montmorillonites using various methods including temperature-programmed reduction (TPR)

Published online by Cambridge University Press:  09 July 2018

C. Ghesquiere
Affiliation:
Groupe de Physico-chimie Minérale et de Catalyse, Université Catholique de Louvain
J. Lemaitre
Affiliation:
Groupe de Physico-chimie Minérale et de Catalyse, Université Catholique de Louvain
A. J. Herbillon
Affiliation:
Section de Physico-chimie Minérale du Musée Royal de l'Afrique Centrale and Université Catholique de Louvain, Place Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium

Abstract

A number of Ni-hydroxy-montmorillonite complexes were prepared by titrating NiCl2 solutions with NaOH in the presence of charge-reduced and normal montmorillonite suspensions. These complexes were characterized by chemical analysis, CEC, XRD, IR and temperature-programmed reduction (TPR). The R (charge-reduced) Ni-hydroxy complexes proved to be merely mechanical mixtures of Ni(OH)2 and clay. The reducibility of Ni contained in these samples was not affected by preliminary heat treatments. The nature of the N (normal) Ni-hydroxy montmorillonites depended principally on the amount of Ni actually incorporated into the precipitates. Neither the OH/Ni ratio selected for the preparation or the quantity of Ni initially added completely determined the type of complex formed. TPR patterns of the N samples generally showed three reduction bands whose respective intensities varied with the quality and the amount of Ni present. One of these reduction bands, occurring at high temperature, measured the extent of incorporation of Ni into the silicate framework during the TPR run. The intensity of this high-temperature band with respect to lower temperature ones was increased by thermal pretreatments. The results emphasize that when TPR patterns of natural Ni-bearing clays are being interpreted it is important to recognize that thermal transformations may occur in the samples caused by the heat supplied during the TPR run itself.

Resume

Resume

On a préparé divers complexes montmorillonite cations hydroxynickel en titrant des solutions de NiCl2 par NaOH en présence de suspensions de montmorillonite normale et de montmorillonite à charge réduite. Ces complexes ont été caractérisés per analyse chimique, par détermination de la CEC, par diffraction X, par spectroscopie infrarouge et par réduction programée en température (TPR). Les complexes de type R (R = montmorillonite à charge réduite) sont de simples mélanges mécaniques constitués d'argile et d'hydroxyde de nickel. La réductibilité du nickel contenu dans ces complexes n'est pas affectée par des traitements thermiques préliminaires. La nature des complexes du type N (N = montmorillonite normale) dépend essentiellement de la quantité de nickel réellement incorporée dans le complexe. Ni le rapport OH/Ni sélectionné pour réaliser la précipitation, ni la quantité de nickel initialement mise en oeuvre ne déterminent complètement le type de complexe formé. Les diagrammes de thermoréduction de ces complexes montrent généralement trois types d'accidents dont l'intensité respective est diagnostique du type de complexe formé. Un de ces accidents, survenant à haute température, est une mesure de la quantité de Ni qui reste coincée entre les feuillets de montmorillonite suite au traitement thermique nécessaire pour l'analyse en thermoréduetion. Cette quantité augmente si l'échantillon est soumis à des traitements thermiques préalablement à son analyse par TPR. Les résultats obtenus mettent l'accent sur la nécessité d'interpréter les diagrammes TPR de minéraux nickelifères naturels en gardant à l'esprit les éventuelles transformations que peut subir tout échantillon suite à l'élévation de température que nécessite son examen en thermoréduction programée.

Kurzreferat

Kurzreferat

Eine Vielzahl von Ni-Hydroxy-Montmorillonit-Verbindungen wurde durch Titration von NiCl2-Lösungen mit NaOH in Suspensionen mit ladungsreduzierten und normalen Montmorilloniten hergestellt. Diese Verbindungen wurden durch chemische Analyse, Kationenaustauschkapazität, XRD, IR und temperaturprogrammierte Reduktion (TPR) charakterisiert. Die R (ladungsreduzierter) Ni-Hydroxy-Verbindungen erwiesen sich als bloße mechanische Mischungen von Ni(OH)2 und Ton. Die Reduzierbarkeit des in diesen Proben enthaltenen Ni wurde durch vorausgegangene Hitzebehandlung nicht beeinträchtigt. Weder das für die Herstellung gewählte OH/Ni-Verhältnis, noch die Menge des unmittelbar zugeführten Ni bestimmte ausschließlich die Art der entstandenen Verbindung. TPR Diagramme zeigten bei den N-Proben meist drei Reduktionsbanden, deren Intensitäten mit der Art und Menge des vorhandenen Ni variierten. Eine dieser Reduktionsbanden, die bei hohen Temperaturen auftritt, gab den Umfang der Ni-Einlagerung in das Silicatgitter während des Ablaufes von TPR an. Die Intensität dieser Hochtemperaturbande wurde im Vergleich zu jenen bei tieferen Temperaturen durch vorausgehende thermische Behandlungen verstärkt. Die Resultate unterstreichen, daß bei der Interpretation von TPR-Diagrammen natürlicher Ni-führender Tone die Berücksichtigung möglicher temperaturbedingter Veränderungen, die während des TPR-Ablaufes selbst auftreten können, wichtig ist.

Resumen

Resumen

Se prepararon una serie de complejos montmorillonitahidróxido de niquel valorando soluciones de Cl2Ni con NaOH en presencia de suspensiones de montmorillonitas con carga reducida y normales. Estos complejos fueron caracterizados mediante análisis quimico, C.C.C., DRX, IR y Reducción a Temperatura Programada (RTP). Los complejos R (carga reducida)-hidroxi-Ni se comprobó que eran mezclas mecánicas de Ni(OH)2 y arcilla. La reducibilidad del niquel contenido en dichas muestras no fué afectada por los tratamientos térmicos preliminares. La naturaleza de los complejos N (normal) hidroxi-Ni dependía principalmente de la cantidad de níquel incorporado a los precipitados. Tanto la relación OH/Ni elegida para la preparación como la cantided de níquel inicialmente añadida eran insuficientes para determinar completamente el tipo de complejo formado. Los diagramas RTP de las muestras N mostraban generalmente tres bandas de reducción cuyas intensidades respectivas variaban con la calidad y la cantidad de Ni presente. Una de dichas bandas de reducción, que aparecia a altas temperaturas, media el grado de incorporación de Ni en la red del silicato durante el ensayo de RTP. La intensidad de esta banda a alta temperatura respecto alas de baja temperatura aumentaba con los pretratamientos térmicos. Los resultados demuestran que cuando se interpreten los diagramas RTP de las arcillas-Ni naturales es importante tener en cuenta que pueden ocurrir transformaciones térmicas en la muestra producidas por el calor aportado durante el propio ensayo del RTP.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

Access options

Get access to the full version of this content by using one of the access options below.

References

Ahlrichs, J.L. (1968) Hydroxyl stretching frequencies of synthetic Ni-, Al-, and Mg-hydroxy interlayers in expanding clays. Clays Clay Miner. 16, 6371.CrossRefGoogle Scholar
Barnishel, R.I. (1977) Chlorites and hydroxy interlayered vermiculite and smectite. Pp. 331356 in. Minerals in Soil Environments (Dixon, J. B. & Weed, S. B., editors). American Society of Agronomy, Madison, Wisconsin.Google Scholar
Bernas, B. (1968) A new method for decomposition and comprehensive analysis of silicates by atomic absorption spectrometry. Anal. Chem. 40, 16821686.CrossRefGoogle Scholar
Brindley, G.W. & Kao, C.C. (1980) Formation, compositions and properties of hydroxy-Al- and hydroxy-Mg-montmorillonite. Clays Clay Miner. 28, 435443.CrossRefGoogle Scholar
Calvet, R. & Prost, R. (1971) Cation migration into empty octahedral sites and surface properties of clays. Clays Clay Miner. 19, 175186.CrossRefGoogle Scholar
Glaeser, R. & Mering, J. (1967) Effet du chauffage sur les montmorillonites saturées de cations de petit rayon. C.R. hebd. séanc. Acad. Sci. Paris 265, 833835.Google Scholar
Hsu, P.H. (1968) Heterogeneity of montmorillonite surface and its effect on the nature of hydroxy-aluminium interlayers. Clays Clay Miner. 16, 303311.CrossRefGoogle Scholar
Lemaître, J. & Gérard, P. (1981) Characterization of hydrous nickel containing silicates by temperatureprogrammed reduction. Bull. Miner. 104, 655660.Google Scholar
Lycourghiotis, A., Defossé, C, Delannay, F., Lemaître, J. & Delmon, B. (1980) Effect of sodium on the Co-Mo/γ-Al2O3 system. I. Influence of sodium on the state of dispersion and on the nature of the cobalt supported on γ-Al2O3 . J. Chem. Soc. Faraday Trans. I 76, 16771688.CrossRefGoogle Scholar
Mackenzie, R.C. (1952) A micromethod for determination of cation-exchange capacity of clay. Clay Miner. Bull. 1, 203205.CrossRefGoogle Scholar
Poncelet, G., Jacobs, P., Delannay, F., Genet, M., GÉRard, P. & Herbillon, A. (1979) Etude préliminaire de la localisation du nickel dans une garniérite naturelle. Bull. Miner. 102, 379385.Google Scholar
Rich, C.I. (1968) Hydroxy interlayers in expansible layer silicates. Clays Clay Miner. 16, 1530.CrossRefGoogle Scholar
Robertson, S.D., McNicol, B.D., Debaas, J.M., Kloet, S.C. & Jenkins, J.W. (1975) Determination of reducibility and identification of alloying in copper-nickel-on-silica catalysts by temperature-programmed reduction. J. Catal. 37, 421431.CrossRefGoogle Scholar
Trescases, J.J. (1975) L'évolution géochimique supergène des roches ultrabasiques. Formation des gisements nickelifères de Nouvelle Calédonie. Mémoire ORSTOM 78, Paris, 259 pp.Google Scholar
Siffert, B. & Dennefeld, F. (1968) Sur la synthèse d'une montmorillonite nickelifère. C.R. hebd. Séanc. Acad. Sci. Paris 267,15451548.Google Scholar
Yamanaka, S. & Brindley, G.W. (1978) Hydroxy-nickel interlayering in montmorillonite by titration method. Clays Clay Miner. 26, 2124.CrossRefGoogle Scholar

Send article to Kindle

To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

An investigation of the nature and reducibility of Ni-hydroxy-montmorillonites using various methods including temperature-programmed reduction (TPR)
Available formats
×

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

An investigation of the nature and reducibility of Ni-hydroxy-montmorillonites using various methods including temperature-programmed reduction (TPR)
Available formats
×

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

An investigation of the nature and reducibility of Ni-hydroxy-montmorillonites using various methods including temperature-programmed reduction (TPR)
Available formats
×
×

Reply to: Submit a response


Your details


Conflicting interests

Do you have any conflicting interests? *