Regarding the issue of sodium chlorate content in the caustic soda produced by the ion-exchange membrane process
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Last edited by sunjl1981 on 2013-1-6 23:21 in this post. Question: What is the relationship between the sodium chlorate content in the alkaline product (32%) exiting the electrolyzer and the sodium chlorate content in the feed brine?； It seems that at present, conclusions are drawn only through experiments or data from actual operations; it’s not clear whether there are any relevant formulas for calculation or estimation. When dealing with customers, some of them have requirements regarding the sodium chlorate content in the finished alkali (32%), so there should be corresponding requirements for the sodium chlorate content in the feed brine as well. May I ask experts, what is the relationship between the two? This post was last edited by limingshuguang on 2007-12-7 08:46 ] # ， ， &
:L: L Please give me some advice
As far as I know, ion exchange membranes can be used with or without the addition of acid. However, in both cases, there are strict requirements regarding the chloride content in the water fed into the membrane. Unless saltwater is to be purified without using resin, what kind of process is the original poster using? Chlorates in the finished alkali are mainly due to chlorate ions penetrating from the anode to the cathode along with the brine; the specific amount depends on the condition of the membrane, but generally, products to which acid has been added contain lower levels of chlorates. So far, no specific calculation formula has been heard of; if the landlord comes across one, please share it with us all!
Thank you for your analysis; it’s the caustic soda process in chlorine engineering, and acid is generally added in that process. The brine entering the electrolyzer consists of secondarily refined brine (brine that has been filtered and refined through a chelating resin column) and recycled fresh brine, with a flow ratio of approximately 1. The ion exchange membranes used are generally Asahi Glass’ F-8020 or DuPont’s N-2030. Well, yes, there is no similar formula available at the moment; only experimental data exists.
On your material balance sheet for the chlorine project, isn’t the amount of chlorate in the caustic soda at the electrolyzer outlet specified there? Is there no formula included in it?
Sodium chlorate in the alkali accumulates over time within the system; there is a certain relationship between sodium chlorate in the alkali and that in the brine. This level can be gradually reduced by increasing the amount of acid added to the electrolyzer, and our unit uses this method – after increasing the acid dosage in the electrolyzer for a period of time, both the sodium chlorate content in the dilute brine and in the alkali decreases. Another method to reduce sodium chlorate is to increase the chlorate decomposition tank, but it requires a large amount of steam.
upstairs asked about the process involved in the chlorate decomposition tank, how it is set up – is sugar added?