The
brick lining in this pump tank has been compromised such that the acid has leaked through
the brick lining to the carbon steel shell. The carbon steel shell has corroded
completely through exposing the sulphate that has built up between the brick and the
shell.
When
acid penetrates through the brick lining of a flat bottom pump tank, the carbon steel
shell will corrode resulting in sulphate formation. The sulphate formed occupies a
greater volume than the parent material and begins to exert pressure on the shell and the
brick lining. One of two things can happen: the brick floor heaves upward or the
flat bottom begin to bulge. In the pump tank pictured here, the bottom has begun to
bulge causing the edges of the pump tank to lift off the support grillage.
Acid
that has penetrated the wall lining will attack the carbon steel shell and form sulphate
between the shell and brick. The pressure that builds up usually cannot push the
bricks out because they are in compression. The only release for the pressure build
up is to cause the carbon steel shell to bulge outwards as seen in the picture.
