What alkali can be added to raise the pH level of antifreeze after it drops?
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1. To prevent the heating water from freezing due to temporary shutdown, antifreeze with a temperature rating of -40 degrees Celsius is used； 2. Should the antifreeze be drained during the non-heating period? ； 3. If the pH value of antifreeze is below 7, what base can be used to adjust it? ； 4. Is potassium dihydrogen phosphate to be used? Should a solution of potassium dihydrogen phosphate be prepared first and then added? I don’t know what the ratio of the solutions is; how much solution needs to be added in total? Thank you very much to all of you. reward_7ree
Trisodium phosphate is generally used; adjusting the pH to 7.5–8 is sufficient. It’s best not to expose it to air, as oxidation can occur and cause the pH level to drop.
I used to directly apply sodium hydroxide, preparing a concentrated alkaline solution and adding a small amount of it.
I used to directly apply sodium hydroxide, preparing a concentrated alkaline solution and adding a small amount of it.
This post was last edited by zjing80 on 2016-4-26 09:03. Sodium carbonate is the best choice as it allows for better control of the pH value; sodium hydroxide can also be used, but it’s easy to go too far with its effect. The solution suggested in the first comment is also good!