Trisodium Phosphate (TSP),
available at most hardware stores in white powder form, is a cleaning agent,
stain remover and degreaser, commonly used to prepare surfaces for painting. It can also be
called trisodium orthophosphate and has the
chemical formula
Na3PO4; however, it is generally found in hydrated forms. It is a highly
water-soluble ionic salt. Solutions of it dissolved in water have an
alkaline
pH.
Trisodium phosphate can also be found as a food additive; it
is used as an acidity
regulator (buffering
agent), emulsifier,
thickening agent,
nutrition enlargement agent and
sequestrant (metal-chelating
agent). In these uses, all
sodium phosphates
may be collectively referred to as sodium phosphate, or by
E number E339. The
same is true when sold as an
enema, working as
a laxative to
treat constipation.
Sodium phosphate enemas are sold
over-the-counter
in the United States. However, it should not be confused with the related
compounds sodium
dihydrogen phosphate, also known as monosodium phosphate or MSP, and
disodium phosphate.
Similar chemicals were once common in
laundry and
dishwashing
detergents, but
the phosphate,
being a fertilizer,
would cause algal blooms
in the bodies of water that the drains led to. In the early
1970s the use of
phosphate-containing products was limited. Now products sold as
TSP Substitute,
containing 80–90% sodium
carbonate, are promoted as a direct substitute.
Cleaning products labeled as
TSP may
contain other ingredients as well, and may in fact be less than half TSP. So
even "regular" TSP found at the hardware store may be half TSP and half "TSP
substitute". Some large home improvement centers that sell paint no longer offer
TSP.
Although it is the active ingredient in at
least one toilet bowl cleaning tablet,
Trisodium phosphate is generally not good for cleaning
bathrooms, because it can corrode metal.
Trisodium phosphate is commonly used after cleaning with
mineral spirits in
order to then clean up all the mineral spirits. TSP may be used with household
chlorine bleach in
the same solution, and this is particularly good for removing
mildew from wood.
The TSP alone can cause dark stains on
redwood, and
bleach prevents it.
Also used in various forms as a boiler
treatment chemical for calcium precipitation, as well as regulating the caustic
effects of disodium
phosphate in coordinated phosphate chemistry.
Also used to clean swimming pool polyester
filter elements.
|
Specification |
TSP Crystals |
TSP Anhydrous |
|
P2O5 content
Assay
Loss on Drying
pH of 2% Solution
Insolubles
Packing |
19%
98%
Less than 58%
11.5-12.5
Less than 0.025%
50 Kg HDPE
Bags |
49.5%
98%
1% max
11.5-12.5
Less than 0.05%
50 Kg HDPE
Bags |
