Menetelmä päällystetyn titaanidioksidipigmentin valmistamiseksi

• Main Authors: RACKHAM,JOHN MICHAEL, HUMPHREYS,JOHN PITCAIRN, LEDERER,GERALD
• Format: Patent
• Language: Finnish; Swedish
• Published: 10.04.1975
• Edition: 2
• Subjects: ADHESIVES; CHEMISTRY; COMPOSITIONS BASED THEREON; DYES; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; ORGANIC MACROMOLECULAR COMPOUNDS; PAINTS; POLISHES; PREPARATION OF CARBON BLACK; THEIR PREPARATION OR CHEMICAL WORKING-UP; TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS

1,142,974. TiO 2 coated with silica and alumina. BRITISH TITAN PRODUCTS CO. Ltd. 29 Jan., 1968 [10 March, 1967], No. 11379/67. Heading C1A. [Also in Division C3] Pigmentary TiO 2 is coated with hydrous oxides of Si and Al, the coating containing 60-90 mole per cent SiO 2 and 40-10 mole per cent Al 2 O 3 , and the amount of SiO 2 being 9-15% by wt. of the uncoated TiO 2 . The coating may be formed by adding Na silicate and Na aluminate, mixed or separately, as solutions or as solids, to an aqueous dispersion of the TiO 2 . Alternatively, Al 2 (SO 4 ) 3 and NaOH may be added in either order to raise the pH to at least 10, and the silicate then added. The dispersion may then be stirred for at least 30 mins. at 40‹ C. and H 2 SO 4 added to reduce the pH to 4-6, then stirred for at least 30 mins. at 50‹ C., flocculated with up to 0À25% MgSO 4 , filtered, dried and fluid energy milled in the presence of pentaerithritol or triethanolamine. The TiO 2 may have a mean wt. particle size of 0À15-0À5Á and may be anatase or rutile. preferably 90-99À5% by wt. rutile. Some of the TiO 2 may be acicular having a length/ width ratio up to 8À1, which may be obtained either (a) by adding to sulphate process TiO 2 0À5-2% (as Na 2 O) of Na 2 SO 4 , Na 2 CO 3 , or NaOH and optionally up to 0À5% Al 2 O 3 , a silicate, and NH 4 H 2 PO 4 , and calcining at 850- 950‹ C., or (b) by seeding a TiCl 4 solution with a TiO 2 sol, heating to form TiO 2 , and calcining at 700-900‹ C. Alternatively, the TiO 2 may be obtained by vapour phase oxidation of TiCl 4 . The TiO 2 may initially be sand-milled, in the presence of a dispersing agent, e.g. Na silicate, which forms part of the silicate reactant.