The issue with sulfuric acid concentration!
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Recently, we’ve encountered a strange phenomenon here: the acid concentration in the circulation acid tank seems to be at the appropriate level based on experience, but the test results from the laboratory are lower. All the reagents used in the laboratory are the same as before, so it’s unlikely that the problem lies with the reagents; moreover, the lab technicians are still the same ones as before! I would appreciate it if the experts here could give me some guidance.
It depends on whom you trust more. Feelings are sometimes the easiest to deceive.
The standard solution needs to be recalibrated. Personally, I feel that the standard solution isn’t standard at all; by using time and acid concentration as coordinates to create a trend graph, the curve representing acid concentration follows a sine wave pattern as time goes by, and I’ve marked that curve. It’s unclear whether this phenomenon is caused by uneven skill levels or by the fact that the analysts lack a meticulous and dedicated work ethic.
The weather is humid, and sulfuric acid absorbs moisture from the air. Therefore, the sampling and analysis processes should try to avoid contact with air as much as possible.
Acid concentration analysis is carried out using acid-base titration; it is not very difficult, and one can check for any systematic errors. In recent years, I have visited many factories and discussed this matter with numerous colleagues in the industry. I’ve heard from industry peers that cases of incorrect preparation of standard solutions have occurred, which should also fall under the category of systematic errors.
Also, try using a new burette – replace your current one with a new one.
This post was last edited by yi*aofei001 on 2010-8-1 08:35. There are too many steps involved in the determination of acidity, from sample collection to the obtaining of analysis results, and these steps can affect the final analysis outcomes. Carefully check every step one by one.
Special attention should be paid to the titration method; moreover, concentrated sulfuric acid absorbs water after sampling, which will certainly cause certain errors. How to isolate it from air is a problem.
Add an online sulfuric acid concentration detector or a control system; the investment is not high – over 20,000 yuan is sufficient for the detector, transmitter, and controller.
It’s probably the acid that has absorbed the moisture from the air, causing its concentration to decrease.