Please analyze what causes the spots on the ion membrane.
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This post was last edited by sunjl1981 on 2013-1-6 at 20:16. Our company uses Beihua Machinery films together with Asahi Kasei F4403 films; after operating for some time, several of these films turned red and developed brown spots. Please analyze what could be causing this phenomenon and what precautions should be taken in the future This post was last edited by yzhms on 2009-3-1 00:13 ] # ， ， &
The image won’t open; please upload another one. Is it easier to judge this way? It’s impossible to figure things out just by talking about it
Also, how long has your membrane been in use?
Spots on the ion membrane: generally, the anode side turns red, due to the deposition of iron and other impurities； Spots appear on the cathode surface, resulting from the peeling and contamination of the cathode coating. The reasons for this reddening include: 1. Contamination by anti-caking agents; 2. Excessive amount of ferric chloride; 3. Corrosion of carbon steel pipes; 4. Decreased adsorption capacity of the resin; 5. Excessive content of regenerated ferric acid; 6. Contamination of the circulating brine with acid; 7. Chemical reactions occurring as a result of broken resin entering the electrolysis system; 8. Chemical reactions occurring as a result of the sedimentation aid sodium polyacrylate entering the electrolysis system. Spots on the cathode surface and peeling of the cathode coating can be caused by: 1. Pores in the membrane; 2. Tears in the membrane; 3. Delayed activation of the polarization rectifier; 4. Delayed cleaning of the tank; 5. Presence of chlorine or chlorates in the pure water; 6. Operation at low current density for extended periods; 7. End of the membrane’s service life; 8. End of the electrode plates’ service life
For a better quality model, the membrane should be replaced every 4 years. I almost couldn’t make it for 2 years.
Is the iron level too high? Check the iron content in the saline. Whether there is a problem with the plates. Ask the manufacturer.
What the original poster mentioned is something I have encountered before: the secondary saline ICP analysis showed satisfactory results, yet the aforementioned issue still occurred. That is: the ion membrane turns red, with dark brown spots appearing in some areas. What we analyzed over there was an excess of iron (caused by ferrocyanide). The appearance of spots is due to unstable operating pressure; the ion membrane comes into contact with the anode at that point and is subjected to external pressure. When iron ions from the brine enter the ion membrane, the greater force exerted on the membrane at that location compresses its internal channels, preventing the iron ions from diffusing and accumulating in those channels in a timely manner, thus resulting in the formation of \"salt deposits\" (saline substances). Over there, we once encountered a situation where the anode was dark brown in color while the cathode turned black (as if it had been scalded). I’m not entirely sure about the reason for this, so I hope everyone can offer some guidance! If there are any issues, please feel free to give your advice. This post was last edited by limingshuguang on 2009-3-3 12:58.]
Personally, I think that if it’s the effect of iron, a uniform red coating should form on the membrane. Instead of spots.
We have those too, and there are blisters as well; I think the spots are caused by the accumulation of impurities
The spots that form are present in some areas but absent in others; they are not present on the entire membrane
The membrane was put into use on May 26th, and it has been in use for about 4 months. I’m having trouble converting images to PDF format – could someone please give me some advice?
Edit your post; there’s a place to upload files below
Why? Share your thoughts~ Personally, I think iron impurities can also cause spots~ they just cover a larger area~