Cadmium paint pigments

Pollution caused by heavy metals is now a worldwide phenomenon. Among the many heavy metals, lead (Pb), mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr), zinc (Zn), and copper (Cu) are of most concern, although the last three metals are essential nutrients in animal and human nutrition. These metals are widely used in industry, particularly in metal-working or metalplating, and in such products as batteries and electronics. They are also used in the production of jewelry, paint pigments, pottery glazes, inks, dyes, rubber, plastics, pesticides, and even in medicines. These metals enter the environment wherever they are produced, used, and ultimately discarded. 

Cadmium ranks close to lead and mercury as a metal of current toxicological concern. Cadmium is used in electroplating and galvanization, and in plastics, paint pigments (cadmium yellow), and nickel-cadmium batteries. Because <5% of the metal is recycled, environmental pollution is an important consideration. Coal and other fossil fuels contain cadmium, and their combustion releases the element into the environment. Extraction and processing of zinc and lead also lead to environmental contamination with cadmium. Workers in smelters and other metal-processing plants may be exposed to high concentrations of cadmium in the air however, for most of the population, food is the major source of cadmium. 

Lead is fotmd in paints, pigments, solder, etc. Mercury has been used in lighting applications and automotive switches, etc. Cadmium is in plastic pigmentation and photocells for nightlights, etc. Hexavalent chromium is used in metal finishing for corrosion prevention, while polybrominated biphenyls and polybrominated diphenyl ethers are flame retardants for several plastics. 

Mercury. Sometimes called quicksilver, mercury is the only common metal that is liquid at ordinary temperatures. It is a feir conductor of electricity and of high density. It is used in barometers and thermometers, to recover gold from its ore, and to manu-fecture chlorine and sodium hydroxide. Its vapor is used in street lights, fluorescent lamps, and advertizing signs. Mercury compounds have various uses, such as insecticides, rat poisons, disinfectants, paint pigments, and detonators. Mercury easily is alloyed with silver, gold, and cadmium. 

Cadmium Cd 0.01 Platings, ink pigments, paint pigments, batteries, detectors, and thick film circuits... 

Other sources of potential environmental contamination by cadmium are cigarette smoke, electroplating processes, paint pigments, the cadmium-nickel type of automobile storage battery, certain phosphate fertilizers, and some of the older types of galvanized water tanks. 

The most common toxic metals in industrial use are cadmium, chromium, lead, silver, and mercury less commonly used are arsenic, selenium (both metalloids), and barium. Cadmium, a metal commonly used in alloys and myriads of other industrial uses, is fairly mobile in the environment and is responsible for many maladies including renal failure and a degenerative bone disease called "ITA ITA" disease. Chromium, most often found in plating wastes, is also environmentally mobile and is most toxic in the Cr valence state. Lead has been historically used as a component of an antiknock compound in gasoline and, along with chromium (as lead chromate), in paint and pigments. 

Cadmium Pigments. J. R. J. van Asperen de Boer, Molecular Aspects of Ageing in Painted Works of Art, Progress Report 1995-1997, FOM Institute for Atomic and Molecular Physics, Amsterdam, NL, http //www.amolf.nl/research/biomacromolecular mass spectrometry/molart/progress report98.pdf... 

Due to its good opacity, the pigment is recommended in general industrial paint applications for lead- and cadmium-free formulations. 

Paint spraying Solvents, pigments (cadmium, chromates, lead)... 

Electrolux is the world s largest producer of powered appliances for kitchen, cleaning and outdoors. They have created comprehensive Environmental Product Declarations (EPDs) for many of their product lines. Information within the product profiles details chemicals that have been banned as well as the percentage and types of materials and how they have improved material choices. Forexample, plastic components do not contain cadmium, lead, mercury or their compounds or chlorinated or brominated flame retardants metal components are not coated with cadmium, chromium, or nickel and metal paints do not contain pigments and additives based on heavy metals. Many Electrolux products are also PVC-free. 

Cadmium sulfate (CdS), also called orange cadmium, is used to produce phosphors and fluorescent screens. It is also used as a pigment in inks and paints, to color ceramics glazes, in the manufacture of transistors in electronics, photovoltaic cells, and solar cells, and in fireworks. 

CdSe forms solid solutions with CdS which are used as pigments ranging in color from orange to deep maroon and are called cadmium sulfoselenides. Other uses are in photocells, rectifiers, luminous paints, and as a mby colorant for glass manufacture. CdSe currently sells for 1.50/g as ph osphor-grade (99.999% purity) material. 

A further use of cadmium pigments is in paints and coatings (powder paints, silicone resins, and automotive topcoats) but this is declining. 

Cadmium fluoride has similar uses to the zinc halide. Cadmium oxide is used in ceramic glazes the sulfate, as a source of other cadmium compounds and in the radio valve industry the sulfide is important as a yellow pigment for artists, and is used in the paint, soap, glass, textile, paper, rubber and pyrotechnics industries. Cadmium sulfide in admixture with other compounds such as the selenide gives rise to other pigments of value. It is also used in phosphors and fluorescent screens and in scintillation counters. Semiconductors such as CdS... 

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