HIGHLY ACIDIC COMPOSITIONS COMPRISING ZIRCONIUM OXIDE, TITANIUM OXIDE AND TUNGSTEN OXIDE AND TREAT

文件类型：PDF文档
文件大小：954K
Compositions useful for treating exhaust gases contain zirconium, titanium and tungsten oxides, and optionally the oxide of an element M selected from among silicon, aluminum, iron, molybdenum, manganese, zinc, tin, and rare earths in the following mass proportions of these different elements : titanium oxide : 20%-50%; tungsten oxide : 1%-20%, M-element oxide : 1%-20%; the balance being zirconium oxide; such compositions are prepared by placing in a liquid medium a zirconium compound, a titanium compound, optionally an M-element compound and a basic compound, adding a tungsten compound to the precipitate suspension thus obtained and having a pH value ranging from 1 to 7, maturing the suspension resulting from the preceding step, and optionally separating the precipitate and calcining same.