Mineral iron oxide inorganic pigments are used for the production of artificial decorative stone. This is a common group of dyes obtained on the basis of iron oxides; therefore, such pigments are called iron oxide pigments. Inorganic synthetic pigments are characterized by their pure color, high dispersion and coloring power (intensity), absence of abrasive impurities and easy dispersive ability in film-forming agents and polymers. Harmless. Light and weather resistant, i.e. they do not fade or wash out of the artificial stone body. Currently, the pigments made in Germany, Czech Republic, Korea, China are available for sale.
Powder pigments are ideal for volumetric coloring and application of pigment mask, both for artificial gypsum stone and cement-based facade stone. The main pigment consumption is the coloring of the mortrar in the mass, and the result is evident - the defect will be invisible in case of occurrence of accidental chip or scratch.
Dry powder pigments, consumption is very efficient, from 0.25% for light pastel colours up to 2% for bright saturated colours. The average consumption is about 1% in most cases. The percentage is calculated based on the mass of the binder (gypsum, cement). By mixing six primary colours in various combinations, a huge palette of shades can be achieved. It is advisable to add no more than 3% of pigments of the weight of the binder, the excess can negatively affect the physical properties of the stone. Insufficient colour intensity is usually associated with the increased porosity of the finished product, which occurs due to the excess amount of water, which is required for preparation of the mortrar. The less amount of water is used, the denser is the stone and the richer is the colour. The use of super- and hyperplasticizers allows reducing the amount of water by 1.5-2 times.