Material selection for oxalic acid equipment
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I need to manufacture an oxalic acid dissolution tank (80°C); previously, an enamel tank was used, but it was discarded due to poor heating and stirring performance. Some designers have suggested using titanium, but that seems inappropriate. Hastelloy is expensive, while composite materials might offer a more cost-effective solution. Please share your insights and let’s discuss this together!
There are now composite material panels available, where the base material is Q235 and the surface layer is made of the material of your choice; however, this type of processing is quite difficult, mainly due to issues related to welding. Another relatively cost-effective option is spraying; it is possible to apply dozens of layers of alloy material onto ordinary 304 stainless steel, and of course a thicker layer can also be applied.
306, 314L, 316L, zirconium (Zr), Ti(2), Ti(10), 1Cr18Ni9Ti, and a non-metallic material in the form of rectangular PE (high-density polyethylene) were subjected to corrosion testing in the liquid mixture within an ethylene oxalate regeneration reactor; the suspension period was 1500 hours, and the corrosion rate was measured. It was found that 314L had the highest corrosion rate, followed by 306L, 316L, Ti(10), 1Cr18Ni9Ti, zirconium (Zr), and Ti(2), with PE having the lowest corrosion rate； 1Cr18Ni9Ti is a suitable material for equipment.
Is the corrosivity of diethyl oxalate the same as that of oxalic acid? 1Cr18Ni9Ti is now an obsolete grade, right?
Using a steel lining with PTFE can effectively solve the problem. Our company has experience in manufacturing oxalic acid equipment; feel free to contact me for details.
A regular reactor lined with graphite will suffice.
It is recommended to choose glass-lined equipment; it is inexpensive, smooth, has good thermal conductivity, helps preserve freshness, and does not react with other materials – features that are unmatched by equipment made from other materials. As for stirring, the type of stirrer to be used should be chosen based on factors such as the percentage concentration and viscosity of the medium inside the tank; combining different stirrer types with appropriate baffles can increase the reaction efficiency by 2-3 times.
This method is certainly good, as it can replace advanced materials. The key is that any coating has micropores; if these micropores are not sealed, the coating will peel off, and sealing agents are crucial.
This post was last edited by liushen203 on 2013-9-10 at 18:54. It’s a PTFE lining; message me
Using titanium is absolutely not feasible, as it corrodes rapidly in hot oxalic acid at moderate concentrations. Considering mechanical properties, the most suitable material is tantaline, a nanotantalum surface alloy with a 316L matrix; its price is only half that of titanium, yet its service life is similar to that of pure tantalum
If there are no particles at 80 degrees, apply F40 – a material imported from Japanese company Daikin. The cost is over 3,000 per square meter; this price does not include the iron core. It is quite suitable for use, and tetrafluoroethylene tape can be used for wrapping and sintering purposes