ZIRCONIUM HYDROXIDE

摘要

This invention relates to an improved amorphous zirconium hydroxide and a method for its production. The hydroxide has a surface area of at least 300m²/g, a total pore volume of at least 0.70cm³/g and an average pore size of between 5nm and 15nm, and is prepared by a process which comprises the steps of : a) preparing an aqueous solution comprising sulphate anions and a zirconium salt such that the ZrO₂: SO₃ ratio is 1:0.40 to 1:0.52, (b) chilling the solution to below 25°C, (c) adding an alkali in order to precipitate the amorphous zirconium hydroxide, (d) filtering and washing the precipitated zirconium hydroxide with water or an alkali to remove residual sulphate and chloride, (e) hydrothermally treating the zirconium hydroxide at a pressure of less than 3 barg, and (f) drying the zirconium hydroxide. The zirconium hydroxide of the present invention, which can be doped, is particularly useful in catalytic applications.