Material selection for fluoride-containing wastewater
Thread Content
There is a project in which the wastewater contains mainly sodium chloride and sodium sulfate, with a pH level between 5 and 6; it also contains 40 ppm of fluoride ions. The goal is to achieve zero discharge using an MVR evaporator, and it is not clear what material would be suitable for this purpose
Firstly, the wastewater is acidic and contains fluoride ions; it’s definitely not possible to use titanium materials for its treatment. If the pH is adjusted to a more alkaline level using alkalis, then what kind of material should be used to handle such conditions?
If it’s alkaline, carbon steel can be used; if it’s acidic, it’s recommended to use plastic pipes – PVC, PTFE-lined, or PO/PP pipes will all work
It will be fine at neutral; we have done similar things before.
Lined with plastic. CPVC. PO is fine too. There are many choices.
It is recommended to use graphite heat exchangers and graphite evaporation separation tanks; as for the material for the compressor, it is advisable to consult the compressor manufacturer. - - - - - - - - - -
However, several people have said that titanium loses much of its corrosion resistance in an environment containing around 300 ppm of fluoride ions, whether in acidic or alkaline conditions; yet no relevant data has been found to date
The amount of wastewater is quite large; using graphite, wouldn’t it be difficult to manufacture large-scale equipment and heat exchangers?
I need to choose the materials for the heat exchange tubes and water pumps; F4 won’t work
Are you adjusting the pH of the wastewater to neutral? How much fluoride ions are contained? How long has the equipment been in use? Are there any problems?