Method and apparatus for the production of tio2 - pigment with improved pigment properties and improved dispersion

摘要

1,258,617. Fuid energy mills. NATIONAL LEAD CO. 10 March, 1969 [14 March, 1968], No.12590/69. Heading B2A. [Also in Division C1] A fluid energy mill comprises a tubular milling chamber 18 ;having jet apertures 32, 33 in the walls of respective sections A and B adjacent plenum chambers 28, 29 formed between inner and outer tubular members 18, 19 and separated by partition 27. Tube 18 threadably engages end plate 22 and abuts onto end plate 21 via gasket 24. Deflector 25 directs inflowing solid/gas suspension (from hopper 14 and venturi 15) against the walls of chamber 18. The apertures 33 in section B are perpendicular to the longitudinal axis of 18 while at least some of the apertures 32 in section A are at an acute angle (e.g. 40-60‹) to this axis opposed to the directions of flow within tube 18. Some of apertures 32 may be at an angle in the direction of flow. The mill is used to treat titanium dioxide pigment (Division C1) by subjecting it to intensive milling in section A, followed by turbulent agitation in section B (without substantial milling). Means for locating a solid, liquid or gaseous dispersing agent 7 is located in section B or between A and B. The milling fluid may be air or steam.