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The Quantity of Reduced Nickel in Synthetic Takovite: Effects of Preparation Conditions and Calcination Temperature

Published online by Cambridge University Press:  28 February 2024

Mark K. Titulaer ,
J. Ben H. Jansen  and
John W. Geus
Mark K. Titulaer
Affiliation:
Department of Geochemistry, Institute for Earth Sciences, University of Utrecht, Budapestlaan 4, P.O. Box 80.021, 3508 TA Utrecht, The Netherlands
J. Ben H. Jansen
Affiliation:
Bowagemi B.V., Prinses Beatrixlaan 20, 3972 AN Driebergen
John W. Geus
Affiliation:
Department of Inorganic Chemistry, University of Utrecht, Sorbonnelaan 16, P.O. Box 80.083, 3508 TB Utrecht, The Netherlands
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Abstract

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Takovite, Ni6Al2(OH)i6CO3-5H2O, with molar Ni/Al ratios of 2.5 and 3 is prepared by precipitation at pH levels of 7 and 10, periods of reaction of 3 and 20 hr, and calcination temperatures varying between 120° and 8 5 3°C. The quantity of reduced Ni is determined as a function of the calcination temperature, and the solid phases remaining after reduction are determined with XRD. The Ni/Al ratio, pH of precipitation, and calcination temperature are important preparation conditions. A precursor of a Ni/Al ratio of 2.5 precipitated at a pH-level of 10 exhibits on reduction metallic Ni particles of about 15 nm irrespective of the drying or calcination temperature. After reduction, a considerable amount of NaAlO2 is present. Metallic Ni particles of 6 nm are present in a reduced precursor of Ni/Al ratio of 2.5 precipitated at a pH-level of 7. The size of the Ni particles present in a reduced precursor of Ni/Al ratio of 3 precipitated at a pH-level of 10 rises from 4–8 nm to 16 nm after calcination at temperatures increasing from 120° to 853°C. The last precursor contains much less sodium, and shows after reduction a disordered NiO phase containing some alumina. Especially, the takovite with the molar Ni/Al ratio of 2.5, thoroughly washed to remove Na, and calcined at T ≤ 260°C before reduction of Ni provides a promising catalyst for the production of hydrogen-carbon monoxide flows out of methane and steam.

Keywords

CalcinationNickel particle sizeTakoviteTemperature programmed reduction
Type
Research Article
Information
Clays and Clay Minerals , Volume 42 , Issue 3 , June 1994 , pp. 249 - 258
Copyright
Copyright © 1994, Clay Minerals Society

Footnotes

*

This paper is a contribution of the Debye Institute, University of Utrecht, The Netherlands.

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