Uses

31 августа, 2015

Pokraskin

Current annual world consumption of cadmium pigments is approximately 2,500 tonnes, used in the following applications:

Table 3.2 Applications of cadmium pigments.

Polymers	90%	All grades ofpolymers and compound masterbatch
Ceramics	6%	Glasses, enamels, porcelain, tile, china and glazes
	3%	Oil colors, water colors, acrylics
Surface Coatings	1%	Coil coatings, automotive paint, high temperature paint

Use of cadmium pigments in polymers is almost universal. Principal polymers of use include HDPE, polystyrene, polypropylene, nylon and ABS. Within Western Europe cadmium pigments are permitted for use in safety applications and in polymers that demand higher processing temperatures. They are also permitted in European toy applications, provided that the colored article conforms to soluble extraction limits of EN71: Part 3. Whereas in Europe the pigments are not permitted to be used in low-density polyethylene (LDPE), they can still be used in masterbatch, which can then be used to color unrestricted polymers.

In the USA, cadmium pigments must conform to TCLP (toxic characteristic leaching procedure) test limits to meet requirements for non-hazardous wastes.

Coloring ceramics can be considered the ultimate test for a pigment, where application temperatures can exceed 1000 °C, considerably beyond the performance limits of any organic pigment. Cadmium pigments offer a unique range of vivid and bright reds, oranges and yellow shades for ceramic applications such as glasses, porcelain and vitreous enamels where high temperature stability is an essential requirement.

The most demanding applications, which involve the highest temperatures for cadmium pigments are “inclusion stains”, in which the pigments are mixed with zirconia and mineralizer to 1000-1100 °C. During this process, the pigment becomes completely encapsulated by a zircon (zirconium silicate) glass that forms a protective coating.