SYNTHESIS AND PROPERTIES OF MG-ZN-AL-SO4 HYDROTALCITE-LIKE COMPOUNDS

Sulphate-based magnesium-zinc-aluminium synthetic hydrotalcite-like co mpounds have been prepared by coprecipitation with a sodium hydroxide solution. The corresponding metal solutions were coprecipitated at pH 10, aged in the mother liquor, washed several times and dried at 40-de grees-C. Whatever the ratio of metal ions in the initial metal sulphat e solutions, hydrotalcite compounds were formed during coprecipitation . The temperature of preparation and ageing time did not effect the fi nal crystal structure. By comparing the properties of the Mg-Al layere d compounds, it seems that when the zinc content increases, the therma l stability of the hydrotalcite-like compounds decreases.