4 ноября, 2015 
Pokraskin Two basic manufacturing processes are distinguished: the precipitation process and the powder process. Common to both of them is that the raw materials must be free of transition metal compounds, which form deeply colored sulfides (e. g. Cu, Fe, Ni, Co, Pb) [3.103].
In the precipitation process, a cadmium salt solution is reacted with sodium polysulfide solution. Zinc salts are then added to produce light yellow cadmium pigments; adding selenium allows hues ranging from orange and red to bordeaux. The precipitate is filtered off, dried, calcined in the absence of oxygen, wet-ground, dried and dry-ground.
In the powder process, finely divided cadmium carbonate or cadmium oxide is subjected to intensive mechanical mixing with sulfur and mineralizers and then calcined in the absence of oxygen. The addition of zinc or selenium produces the same effects as in the precipitation process. The product is worked up in the same way as in the precipitation process. The main producer of cadmium pigments is Millenium (USA).
3.3
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