Fluorescent lamp recycling
Encyclopedia
Fluorescent lamp recycling is the reclamation of the materials of a spent fluorescent lamp
for the manufacture of new products. Glass tubing can be turned into new glass articles, brass and aluminium in end caps can be reused, the internal coating can be reprocessed for use in paint pigments, and the mercury
contained in the lamp can be reclaimed and used in new lamps. In the United States, about 620 million fluorescent lamps are discarded annually; proper recycling of a lamp prevents emission of mercury into the environment, and is required by most states for commercial facilities. The primary advantage of recycling is diversion of mercury from landfill sites; the actual scrap value of the materials salvaged from a discarded lamp is insufficient to offset the cost of recycling.
Only a few tenths of a milligram of mercury are required to maintain the vapor, but lamps must include more mercury to compensate for the part of mercury absorbed by internal parts of the lamp and no longer available to maintain the arc. Manufacturing processes have been improved to reduce the handling of liquid mercury during manufacture and improve accuracy of mercury dosing.
Mercury-free discharge lamps have considerably lower production of visible light, about half; mercury remains an essential component of fluorescent lamps.
A broken fluorescent tube will release its mercury content. Safe cleanup of broken fluorescent bulbs differs from cleanup of conventional broken glass or incandescent bulbs. 99% of the mercury is typically contained in the phosphor, especially on lamps that are near their end of life.
compounds, which were implicated in the deaths of factory workers. However, it is very unlikely that one would encounter any such lamps.
Formerly, toxic materials such as beryllium, arsenic, cadmium, and thallium were used in phosphor manufacture. Modern halophosphate phosphors resemble the chemistry of tooth enamel. The rare-earth doped phosphors are not known to be harmful.
to form mercury sulfide
, which is insoluble in water. One advantage of sulfur is its low cost.
The reaction is shown with the equation:
Hg + S → HgS
The easiest way to combine sulfur and mercury is to cover a group of fluorescent tubes with sulfur dust and break them; when the glass is put into a bag to continue with the reaction, the mercury will combine with sulfur without any other action. The glass can be recycled where an appropriate facility exists. A quantity of 25 kg of dust sulfur is enough for 1000 tubes.
toxins from spent tubes can be an environmental hazard. Governmental regulations in many areas require special disposal of fluorescent lamps separate from general and household wastes. For large commercial or industrial users of fluorescent lights, recycling services are available in many nations, and may be required by regulation. In some areas, recycling is also available to consumers.
Spent fluorescent lamps are typically packaged prior to transport to a recycling facility in one of three ways: boxed for bulk pickup, using a prepaid lamp recycling box, or crushed for pickup. A fluorescent lamp crusher
can attach directly to a disposal drum and contain dust and mercury vapor. Disposal methods are regulated at both the state and federal level. Proper recycling of fluorescent lamps can reduce risk of human exposure to mercury. Companies that recycle spent fluorescent lamps include Air Cycle Corporation
, Waste Management, and Veolia.
Fluorescent lamp
A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...
for the manufacture of new products. Glass tubing can be turned into new glass articles, brass and aluminium in end caps can be reused, the internal coating can be reprocessed for use in paint pigments, and the mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
contained in the lamp can be reclaimed and used in new lamps. In the United States, about 620 million fluorescent lamps are discarded annually; proper recycling of a lamp prevents emission of mercury into the environment, and is required by most states for commercial facilities. The primary advantage of recycling is diversion of mercury from landfill sites; the actual scrap value of the materials salvaged from a discarded lamp is insufficient to offset the cost of recycling.
Mercury in lamps
The amount of mercury in a fluorescent lamp varies from 3 to 46 mg, depending on lamp size and age. Newer lamps contain less mercury and the 3–4 mg versions are sold as low-mercury types. A typical 2006-era 4 ft (122 cm) T-12 fluorescent lamp (i.e., F32T12) contains about 12 milligrams of mercury. In early 2007, the National Electrical Manufacturers Association in the US announced that "Under the voluntary commitment, effective April 15, 2007, participating manufacturers will cap the total mercury content in CFLs under 25 watts at 5 milligrams (mg) per unit. CFLs that use 25 to 40 watts of electricity will have total mercury content capped at 6 mg per unit."Only a few tenths of a milligram of mercury are required to maintain the vapor, but lamps must include more mercury to compensate for the part of mercury absorbed by internal parts of the lamp and no longer available to maintain the arc. Manufacturing processes have been improved to reduce the handling of liquid mercury during manufacture and improve accuracy of mercury dosing.
Mercury-free discharge lamps have considerably lower production of visible light, about half; mercury remains an essential component of fluorescent lamps.
A broken fluorescent tube will release its mercury content. Safe cleanup of broken fluorescent bulbs differs from cleanup of conventional broken glass or incandescent bulbs. 99% of the mercury is typically contained in the phosphor, especially on lamps that are near their end of life.
Phosphors
Lamps made up to the 1940s used toxic berylliumBeryllium
Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...
compounds, which were implicated in the deaths of factory workers. However, it is very unlikely that one would encounter any such lamps.
Formerly, toxic materials such as beryllium, arsenic, cadmium, and thallium were used in phosphor manufacture. Modern halophosphate phosphors resemble the chemistry of tooth enamel. The rare-earth doped phosphors are not known to be harmful.
Mercury containment
When discarding a fluorescent tube, the main concern is the mercury, which is an important pollutant. One way to avoid releasing mercury into the environment is to combine it with sulfurSulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
to form mercury sulfide
Mercury sulfide
Mercury sulfide, mercuric sulfide, or mercury sulfide is a chemical compound composed of the chemical elements mercury and sulfur. It is represented by the chemical formula HgS...
, which is insoluble in water. One advantage of sulfur is its low cost.
The reaction is shown with the equation:
Hg + S → HgS
The easiest way to combine sulfur and mercury is to cover a group of fluorescent tubes with sulfur dust and break them; when the glass is put into a bag to continue with the reaction, the mercury will combine with sulfur without any other action. The glass can be recycled where an appropriate facility exists. A quantity of 25 kg of dust sulfur is enough for 1000 tubes.
Disposal methods
The disposal of phosphor and mercuryMercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
toxins from spent tubes can be an environmental hazard. Governmental regulations in many areas require special disposal of fluorescent lamps separate from general and household wastes. For large commercial or industrial users of fluorescent lights, recycling services are available in many nations, and may be required by regulation. In some areas, recycling is also available to consumers.
Spent fluorescent lamps are typically packaged prior to transport to a recycling facility in one of three ways: boxed for bulk pickup, using a prepaid lamp recycling box, or crushed for pickup. A fluorescent lamp crusher
Fluorescent lamp crusher
A fluorescent lamp crusher is a device that crushes and stores spent fluorescent lamps prior to processing at a recycling facility, while controlling the release of mercury vapor emissions...
can attach directly to a disposal drum and contain dust and mercury vapor. Disposal methods are regulated at both the state and federal level. Proper recycling of fluorescent lamps can reduce risk of human exposure to mercury. Companies that recycle spent fluorescent lamps include Air Cycle Corporation
Air Cycle Corporation
Air Cycle Corporation is a privately-held American recycling and waste management company headquartered in suburban Chicago. The firm offers environmental consulting in addition to its core business providing fluorescent lamp, ballast, battery, and electronic waste recycling products and services...
, Waste Management, and Veolia.
External links
- NEMA paper on recycling household compact fluorescent lamps
- LampRecycle.org Information and directory from the National Electrical Manufacturers Association (NEMA)
- ALMR.org Association website for the Association of Lighting and Mercury Recyclers (ALMR)
- EPA.gov Mercury-containing Light Bulb (Lamp) Recycling