APPLICATIONS FOR SELENIUM
The first commercial application for Se was found during World War 1, as a substitute for critically short manganese, a decolorizer in glass making. A wide variety of industrial applications have since been developed. Average annual usage is currently estimated at 1850 metric tons.
- Electrical: 30% of demand. High purity selenium and selenium alloys are used in photoreceptors for plain paper copiers and laser printers; rectifiers and voltage surge protection devices; CO2 laser windows, infrared detectors, photovoltaic cells, x-ray receptors for medical imaging.
- Pigments: 10% of demand, Cd sulfoselenide compounds are highly stable pigments used in plastics, ceramics, glazes and paints, for products which during manufacturing or use are subjected to moisture, high temperature, ultraviolet or chemical exposure. Se in pigments can produce a wide variety of colors as diverse as red, orange and maroon.
- Glass: 35% of demand. Selenium decolorizes the green tint caused by iron impurities in glass bottles; produces the ruby red color in art glass; reduces solar heat transmission through architectural glass.
- Metallurgy: 10% of demand. Selenium addition improves machinability of carbon steel, stainless steel, copper, and acts as a grain refiner in the grids of low-maintenance lead-acid batteries.
- Agricultural/Biological: 5% of total demand. An essential element to life, Se is added in trace amounts to animal feeds, veterinary preparations, and boluses to prevent certain diseases in animals and increase growth. Soil deficiencies are corrected by adding selenium to chemical fertilizers. In medicine, Se compounds act as a fungicide to control dandruff and dermatitis, and as a human diet supplement for control of certain diseases.
- Other Applications: 10% of total demand. Used as a component in catalysts for selective oxidation; in plating solutions to improve appearance, antiquing effects, and durability; blasting caps; gun bluing; to increase yields in electrolytic manganese production, etc.