How to control sodium carbonate in 32% caustic soda? ?
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This post was last edited by sunjl1981 on 2013-1-6 at 22:17. Recently, 32% of the caustic soda produced by our company has not met the standards for high-quality products; the analysis shows that the sodium carbonate content is always above the allowed limit! What aspects should be considered when the sodium carbonate content is above the standard? What measures should be taken? ? # + + . hcbbs
Hehe, I really want to know too. The content level here is always over 0.1, which is above the standard for premium quality
I feel it’s necessary to avoid exposure to air; there should be very little of it generated during production
This post was last edited by Yinozhang on 2009-8-7 at 10:40. In my opinion, 32% alkali contains a relatively high amount of sodium carbonate. This can be considered from several aspects. First is the source of sodium carbonate: in ion-exchange membrane electrolyzers, since the anode solution is acidic (this applies to electrolyzers used in chlorine production; I’m not familiar with other types of electrolyzers), it’s impossible for the anode to contain sodium carbonate, and thus it’s also impossible for sodium hydroxide at the cathode to be contaminated by sodium carbonate from the anode. Additionally, at the cathode, aside from adding pure water to adjust the concentration, no other substances are added. Therefore, the most likely explanation is that the pure water contains an excessive amount of sodium carbonate. The original poster can test the sodium carbonate content in the pure water. Furthermore, if the finished alkali comes into direct contact with air, and since air contains a certain amount of carbon dioxide, the reaction CO2 + 2NaOH = Na2CO3 + H2O is inevitable, which may also result in an excess of sodium carbonate.
What material are the pipes and tanks used in a 32% alkali system? Is it high-carbon steel? What is the liquid level in the tank? Has it been there for a long time?
Was air stirring used during the configuration? The air can contain carbon dioxide……
6# Sister, ours is ready-made lye; there’s no need for stirring
Are the analysis results incorrect? Try changing the medication……
Generally speaking, for caustic soda produced by devices whose membranes do not age over a short period of time, the sodium carbonate content does not reach high levels; it is usually around 0.04% wt, which meets the standards for premium quality. If this occurs: The first reason is that the opening area of the finished alkali tank is too large, and the alkali inlet pipe enters from the top without reaching the middle or lower part of the tank. (But the impact is minimal.) The second reason: the standards used for analysis are incorrect; if old standards are used, the values will definitely exceed the limits. Moreover, nitrogen protection is required during sampling. Please analyze it from these two reasons, but the second reason is highly likely!
I suggest you check from several aspects: 1. Control of the tank temperature; if it’s too high, salt content will increase； 2. See concentration