Mother liquor water pH value
Thread Content
The pH value of the centrifuged mother liquor water after PVC polymerization in my company is around 10. What is the reason for such a high pH value? How to solve it?
This post was last edited by YongBu※YanQi on 2015-10-27 at 11:54. What kind of buffer does your company use for aggregating feedstock? Is alkali solution added during discharge? Additionally, is the terminator you use water-soluble or oil-soluble? What is the pH value of the original solution, and what is the dosage? Checking from these aspects should help find the answer.
This post was last edited by pvczj0521 on 2015-10-27 at 12:32. The buffer used in our company for feeding materials is ammonium bicarbonate; no alkali is added during the discharge process. The terminator is a water-soluble substance with a pH of 12, and its dosage is normal. Compared to other companies in the same industry, the concentration of the mother liquor in our company is relatively high
The problem might lie with the terminator; you can consult companies that use the same processing method as you, or the manufacturers of the terminator used, to find out the appropriate amount to be used, and to see if too much has been added. When we use water-soluble terminators, the pH value is 14.
Thank you for your help:handshake
The alkalinity of ammonium bicarbonate does not reach the pH 10 range. However, due to the effect of rising temperature, ammonium bicarbonate decomposes to a small extent, and carbon dioxide is released in certain quantities. Since ammonia is highly soluble, it is not released in equal amounts to carbon dioxide; as a result, the amount of ammonia in the system exceeds that of carbon dioxide. This leads to an increase in pH. That is, a small amount of ammonium carbonate is present in the water, and this compound has a greater alkalinity than ammonium bicarbonate.
It’s probably a terminator issue. It is possible to test the pH value of the polymeric water at the reaction stage, as well as the pH value of the water obtained after adding the terminator