Caustic Soda Tanks
Most Caustic Soda Tanks
offered by plastic storage tank distributors are made from Polyethylene.
That is not the best choice if you are storing Caustic tanks are storing concentrations of 50% or higher.
If you look at an
impartial chemical compatibility guide, you will find that
Polyprolypene is a much better choice for Caustic Tanks.
Polyethylene of any type will soften and fail due to the
attack of Caustic Soda in just a few years. Most
plastic tank companies do not mold large
Polypropylene tanks so they just offer the Caustic Soda tanks that they
have, even if it is a poorer choice. Some may tell you
about their special liner or special kind of polyethylene
but the bottom line is that it is still
and Caustic Soda attacks polyethylene. Polypropylene
resists the chemical attack of Caustic Soda and will also
handle higher temperatures than Polyethylene. Check out our
Caustic Soda Tanks made from
Polypropylene. Take a look at a good chemical
resistance guide such as the one at
Caustic tanks need to be specialized to survive long storing Caustic Soda.
Caustic soda is also known as sodium hydroxide, caustic, and
lye. Caustic soda, as a 50% solution, is an odorless and
colorless liquid. In all forms, caustic soda is highly
corrosive and reactive. Caustic soda solution reacts readily
with metals such as aluminum, magnesium, zinc, tin,
chromium, bronze, brass, copper, and tantalum. Galvanized
(zinc coated) materials should be avoided. Contact with
acids, halogenated organics, organic nitro compounds, and
glycol should be avoided. It reacts with most animal tissue,
including leather, human skin, and eyes. It also reacts
readily with various reducing sugars (i.e., fructose,
galactose, maltose, dry whey solids) to produce carbon
Upon cooling, the viscosity of the solution increases
rapidly as the temperature falls below 65°F (18°C).
Caustic soda solution is a stable product but its storage
life is dependent upon the storage conditions. If the
caustic is exposed to air, a change in the product quality
will be seen over time, since the caustic soda solution will
pick up carbon dioxide to form sodium carbonate (Na2CO3) solids. In addition, iron pick up is common in carbon steel
storage vessels or in lined carbon steel storage vessels
where the liner has been damaged. Therefore, minimizing its
exposure to air and its direct contact with iron containing
metals will extend the storage life of caustic soda
solution. A Caustic Soda storage tank with a sealed manway will help keep air from the chemical.
|Much of the information presented here about Caustic Soda
storage is from the Dow Chemical web site. Dow is the
worlds largest producer of Caustic Soda.