Know About Cadmium Yellow Pigment

Cadmium yellow includes light cadmium yellow, deep cadmium yellow, normal yellow, orange yellow and other varieties. The chemical composition of cadmium yellow is basically cadmium sulfide (CdS) or a solid solution of cadmium sulfide and zinc sulfide (Cds•ZnS). Cadmium yellow is similar to cadmium red in many aspects.
Cadmium Yellow Pigment
Cadmium sulfide yellow exists in sulfide cadmium ore in nature. The color of cadmium yellow is bright and saturated (saturation can reach 80%~90%), and its color spectrum can range from light yellow to normal yellow to red light yellow. Cadmium yellow containing ZnS, its yellowness becomes lighter with the increase of the solid solution amount of ZnS, until it becomes pale yellow. The industrially produced cadmium yellow includes light yellow, bright yellow, normal yellow, dark yellow and orange. Studies believe that the color of cadmium yellow does not mainly depend on its atomic orientation or crystal structure, but on secondary factors related to the colloidal aggregation of pigments, and largely depends on the valence of the coagulated anion.

Cadmium yellow pigment is insoluble in water, alkali, organic solvents and oils, slightly soluble in 5% dilute hydrochloric acid, soluble in concentrated acid, dilute nitric acid and boiling dilute sulfuric acid (1:5). Cadmium yellow is not affected by H2S. Cadmium yellow has strong tinting power, excellent light fastness, good weather resistance, no migration and no bleeding. Cadmium yellow is safe in coloring products due to its insolubility, but it is still a toxic pigment. In the application, pay attention to whether the amount of lead and cadmium dissolved meet the requirements of relevant standards. Pay attention to safety when touching its powder. Cadmium pigment dust has adverse effects on human breathing and kidney function.

Cadmium yellow can be combined with the red pigment in any ratio, and colored glazes of various tones ranging from yellow to red can be prepared, and it can also be combined with chromium oxide green to produce yellow-green color glazes. Cadmium yellow and blue pigments can be mixed together to get green. For example, cadmium green is composed of cadmium yellow and cobalt blue, and emerald green is composed of lemon yellow and malachite green.

The artificial synthesis of cadmium sulfide consists of two process routes:
1. Any kind of cadmium salt (such as cadmium carbonate, cadmium chloride, cadmium sulfate, chromium nitrate, etc.) reacts with appropriate sulfides (such as sodium sulfide, hydrogen sulfide, sodium thiosulfate, ammonium sulfide, etc.) in the liquid phase This produces cadmium sulfide.

2. Calcining or melting cadmium or its compounds (such as cadmium carbonate and cadmium oxalate) with sulfur to prepare cadmium sulfide yellow. In the manufacturing process of cadmium sulfide yellow, if zinc is introduced, a solid solution of cadmium sulfide and zinc sulfide is formed. The higher the zinc content, the lighter the yellowness of cadmium yellow.

The preparation method of cadmium yellow pigment generally adopts calcining method and precipitation-calcination method, which is similar to the preparation method of cadmium red pigment. If you are interested in our cadmium yellow pigments, please contact us for more information and free samples, the consultation hotline +8613574208778.