• journal_title：Clays and Clay Minerals
• Contributor：Yongjun Feng ; Dianqing Li ; Chunxi Li ; Zihao Wang ; D. G. Evans ; Xue Duan
• Publisher：Clay Minerals Society
• Date：2003-
• Format：text/html
• Language：en
• Identifier：10.1346/CCMN.2003.0510510
• journal_abbrev：Clays and Clay Minerals
• issn：0009-8604
• volume：51
• issue：5
• firstpage：566
• section：Articles

Hydrotalcite-like layered double hydroxides (LDHs) containing different ratios of Ni²⁺, Cu²⁺, Mg²⁺ and Al³⁺ in the layers have been prepared by a new method, the key features of which are a very rapid mixing and nucleation process in a colloid mill followed by a separate ageing process. The compositions and structural parameters of the materials synthesized using the two routes are very similar, although the degree of crystallinity is slightly higher for the LDHs produced using the new method. The major advantage of the new method is that it produces smaller crystallites, having a very narrow range of distribution of crystallite size. In the conventional coprecipitation process at constant pH, the mixing process takes a considerable time during which nuclei formed at the beginning of the process have a much longer time to undergo crystal growth than those formed at the end of the process. The consequence is that a wide dispersion of crystallite sizes is obtained. In the colloid mill process, however, the mixing and nucleation is complete in a very short time and is followed by a separate ageing process.