Calcium and magnesium issues in brine once
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Sodium hydroxide is kept above 0.4, while sodium carbonate is kept at 0.3; no calcium was detected in the brine after membrane filtration, but magnesium levels are above 100. What is the main issue here? ?
Calcium and magnesium levels in crude salt, what salt production process is used, and is analysis done by titration or ICP?
You haven’t clarified your production process or salt usage, making it difficult to analyze. However, an excess of 0.4 g/I of NaOH is too high. When PH ≥ 12, the crystal form of magnesium hydroxide changes. Some of the magnesium hydroxide changed from ideal flocculent precipitates to crystalline precipitates. Extremely fine magnesium hydroxide crystals are formed, which are difficult to remove completely using either sedimentation or filtration methods.
First, reduce the excess NaOH to 0.1~0.2 g/L.
Where does your raw salt come from? Currently, imported salt has a low magnesium content, and the alkali level should be kept between 0.1 and 0.4; the sodium carbonate level can be higher. Don’t use the new salt right away – let it sit for a month. Check whether less ferric chloride was added, and see if there were any issues with the pre-treatment process
The amount of sodium hydroxide is slightly too high; check also whether the amount of ferric chloride added is sufficient.
Is your salt imported? Where is it usually imported from, and what’s the price?
Generally, it’s best to keep the pH of saltwater around 10; this issue should now be resolved