|
Sodium, calcium, potassium and lithium hypochlorites are strong oxidizing
agents used for bleaching, sanitation and disinfection. Sodium hypochlorite
accounted for 83% of total global hypochlorite use, with calcium hypochlorite
at approximately 17%. Lithium and potassium hypochlorites account for a negligible
share.
World consumption of sodium hypochlorite for household use in 2005 is estimated
at426 thousand metric tons annually on a chlorine equivalent
basis. Consumption of sodium hypochlorite for all other uses, including pool
sanitization, wastewater treatment and drinking water disinfection, pulp and
paper, and textile bleaching was approximately 893 thousand metric tons on
a chlorine equivalent basis.
The following pie chart shows world consumption of hypochlorite bleaches in
2005:
In households, sodium hypochlorite is used principally for household laundry
bleaching and disinfection. Use of household bleach has increased during the
past few years, with growing concern over infectious diseases. Mold and mildew
became an issue in the Gulf Coast region of the United States as a result of
hurricane damage. The number of household disinfectant products containing
chlorine compounds has increased in the past few years.
The principal nonhousehold uses are water treatment and disinfection. The
U.S. market for nonhousehold usage is forecast to grow overall at 2.2% per
year from 2005 to 2010, with municipal/industrial disinfection forecast to
grow at 3.3% with the replacement of gaseous chlorine with sodium hypochlorite.
Legislation regarding the safe handling of gaseous chlorine is pushing users
to make the switch to sodium hypochlorite and other disinfectants. In six to
seven years, new legislation recently approved regarding potable water disinfection
and the creation of disinfection by-products (DBP) will help create new processes
and chemistries for water disinfection. The growth rate in the swimming pool
sanitization market is expected to be about 2% per year.
Except for Asia, world pulp bleaching markets for both sodium and calcium
hypochlorite have decreased significantly because of environmental concerns
regarding adsorbable organically bound halogens (AOX) and their impact on pulp
viscosity. Multistage bleaching processes using chlorine dioxide, hydrogen
peroxide, ozone or oxygen have replaced multistage processes using gaseous
chlorine and hypochlorites to promote elemental-chlorine-free (ECF) bleaching
sequences as a best available technology (BAT).
The global textile bleaching market has also reduced or eliminated sodium
hypochlorite in bleaching, replacing it mainly with hydrogen peroxide. However,
usage continues in Turkey and Asia. With textile growth in China, India and
Turkey, consumption growth is forecast at 5% per year from 2005 to 2010.
|
