Please help choose the material!
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There is an existing extraction and separation tank in which the liquid is stratified; it is necessary to design a level gauge that can show the liquid level inside the tank as well as the position of the stratification layers. The problem is that the solution contains HCl and KF. A glass tube level gauge was used, but it became frosted after just 1 month (it was corroded!) ). Please ask an expert for advice!
It depends on the operating temperature; if it is below 65°C, the glass tube can be replaced with a transparent polyethylene (high-density) tube. Polyethylene can withstand 50% hydrofluoric acid and 38% hydrochloric acid at 60°C. For your reference.
A transparent PFA material should be used; it has the same corrosion resistance and temperature tolerance as PTFE. It does not seem to be produced in China, so it needs to be imported.
It’s a pity I’m a novice in chemistry; I’m here to work hard and learn! I can’t help the original poster; I’m very anxious! I only have research on filters; if the original poster needs it, I’ll do my best with what I know! Contribute my best!
Is it possible to observe the normal liquid level using an interface level gauge? We all use remote controls, the built-in kind
One of the most important corrosion-resistant properties of zirconium is its excellent resistance to corrosion in hydrochloric acid at all concentrations and temperatures, even above the boiling point (see Figure 1)⑥. Hydrochloric acid is the most corrosive inorganic acid; even a small amount of it present in process media can cause severe corrosion of various corrosion-resistant materials such as stainless steels and titanium alloys. Figure 2 shows the anodic polarization curve of zirconium in hydrochloric acid. According to Figure 2, the anodic polarization curve of zirconium in hydrochloric acid shows no activation region, and its pitting potential in hydrochloric acid is lower than its corrosion potential; therefore, zirconium is less prone to crevice corrosion, pitting corrosion, and stress corrosion in hydrochloric acid. This is the fundamental guarantee for the widespread use of zirconium in hydrochloric acid-based industries. However, when certain oxidizing ions such as Fe+3 are present in hydrochloric acid, the corrosion potential of zirconium is polarized beyond its pitting potential, resulting in pitting or stress corrosion (see Figure 3)⑦. Therefore, when zirconium equipment is operating in a hydrochloric acid medium, the presence of other oxidizing ions is not allowed.
It is mainly HF that causes glass corrosion. HCl and KF are strong electrolytes; the H ions and F ions produced by their ionization combine to form HF, which then corrodes the glass. Those who study chemistry should know this, right?:o
I personally recommend using transparent PFA material for this purpose. One person upstairs was incorrect – this material can be manufactured in China; I have encountered it before.
The expert was talking about protection against chlorine corrosion – is it also protection against HF corrosion?
Transparent PTFE level gauges are already available, and they are used in many fluorine chemical plants and chlor-alkali plants here.