In the Solvay process, if the concentration of calcium and magnesium ions in the brine is too high, will it have any effect on soda ash?
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Recently, our company has encountered problems with brine purification. The turbidity levels at both the first and second stages remain high. Apart from this, there are no other adverse effects; however, the production of heavy ash has been affected—it’s practically impossible to carry out continuous production. Unfortunately, relevant literature doesn’t provide any information on this issue. Could all the experts please analyze this situation for us? The turbidity was 700 ppm for the first time, 300 ppm for the second time, and the turbidity of the final product was 300–500.
Is nobody interested in this topic?
This post was last edited by chen-jun-1024 on 2011-10-13 at 09:49. Reply to #1 Jiangbei Piao: May I ask what method your company uses for heavy ash production? Solid state or liquid state? If it’s a solid state, that would be terrible; the liquid state is still tolerable! Is the heating equipment a calciner or a fluidized bed? The calciner is on top, and the fluidized bed is at the bottom!
Upstairs, we have both solid-phase and liquid-phase systems; it’s a heavy-ash fluidized bed. Now, with the drum-type water treatment machine, what is produced are alkali balls the size of yuanxiao; later, the shape of these alkali balls was changed to that of peanuts, then to that of rice grains, and finally to that of alkaline sludge. Once they end up in the fluidized bed, the bed becomes inactive. The oil pump for the liquid-phase centrifuge won’t work (Kema centrifuge); it’s completely useless.
Reply to 4# Jiangbei Piao: If you need any help, feel free to contact me! QQ:909935753
Reply to 4# Jiangbei Piao: Absolutely has an impact! The turbidity of the concentrated brine, as well as its calcium and magnesium contents, have a significant impact on the production of heavy ash; in cases where the solid-phase hydration method is used to an extreme extent, no monohydrate alkali crystals are formed at all, especially with this method. Please reduce the turbidity of the brine!
It’s extremely difficult to reduce the levels of calcium and magnesium in brine. We use the lime-soda process to purify the brine; the turbidity of the resulting soda ash is 150 ppm, which is an order of magnitude lower than that produced by other companies.
Reply to 7# Jiangbei Piao: The amount of water-insoluble substances is high. Could it be that there’s poor control over excess ash and excess alkali?
The key issue is the high magnesium content. We use lime milk to remove magnesium, but the removal isn’t very thorough. Sometimes, when the magnesium level is high, the turbidity can reach 1,000 ppm in a single treatment
Is it possible to remove ions using membrane separation?
Reply to 9# Jiangbei Piao: It’s quite normal to use lime milk for removing magnesium. Could it be that the magnesium content in the raw salt is too high?