What causes the finished acid to turn red?
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This post was last edited by jiabin135792 on 2015-9-14 at 16:05. It does not turn red during production or storage, but it turns red once the tank truck delivers it to the customer. What could be the possible reasons? Light red acid will turn further into dark brown if stored for too long (it has been in the storage tank for over a year). We produce acid from hydrogen sulfide in the petrochemical industry; therefore, storage and transportation issues can be ruled out. Our customers are relatively stable, and there are no problems with the acid transport vehicles
It is recommended to conduct an iron content analysis on the finished acid.
A change in the valence state of iron during transportation can cause the acid to turn red. A high nitro group content in sulfuric acid can also cause discoloration; as mentioned on the second floor, it is necessary to analyze the composition of the acid. There are targeted solutions.
You can refer to the following two posts; before posting, check first to see if there are any identical posts. Information on factors affecting the color of industrial sulfuric acid: http://bbs.hcbbs.com/thread-1108816-1-1.html (Source: Haichuan Chemical Industry Forum) Issues related to color change in 98% sulfuric acid: http://bbs.hcbbs.com/thread-1095219-1-1.html (Source: Haichuan Chemical Industry Forum)
Concentrated sulfuric acid appears red in color; this may be due to iron impurities, but it could also be caused by carbide-forming substances. Although carbide-forming substances are generally brown or dark brown, it is not impossible that certain organic compounds can form impurities of other colors as a result of sulfonation or oxidation. A total iron test can be performed on sulfuric acid, along with an absorption spectrum scan in the visible light range, to roughly determine the type of impurities present in it.
It will also turn red if the nitrogen oxide levels are high
Inspect the tank truck to determine whether it is new and to check what organic material is used as lining
Ferrous iron is blue, ferric iron is yellow; carbides are a more likely possibility
What do you mean by sulfides? Could you specify what type of sulfide it is?
Carbides; sometimes minerals contain organic substances, which undergo carbonization in concentrated sulfuric acid, turning the acid a purplish-red color
Light red acid will turn further into dark brown if stored for too long; it’s not a problem with the tank truck