Hydrated aluminium sulfate precipitation by enzyme-catalysed urea decomposition

Kara F., Sahin G.

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, vol.20, no.6, pp.689-694, 2000 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 20 Issue: 6
  • Publication Date: 2000
  • Doi Number: 10.1016/s0955-2219(99)00202-2
  • Journal Name: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.689-694
  • Keywords: Al2O3, powders-chemical preparation, sintering, urea, THERMAL-DECOMPOSITION
  • Anadolu University Affiliated: No

Abstract

Hydrated basic aluminium hydroxide precipitates were obtained from aluminium sulphate solution at room temperature and at 92 degrees C by using urea. Enzyme urease was used to decompose urea at room temperature. It was observed that precipitates obtained at room temperature were much finer than those obtained at 92 degrees C but they had similar chemistry. On calcination at 1200 degrees C, each precipitate obtained at room temperature converted to a discrete alpha-Al2O3 crystal whereas that obtained at 92 degrees C converted to a rather densely packed agglomerate of alpha-Al2O3 crystals. As a result of this, alpha-Al2O3 powder obtained from 25 degrees C precipitates showed much better sintering behaviour. (C) 2000 Elsevier Science Ltd. All rights reserved.