Regarding the quality issues of high-purity hydrochloric acid
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This post was last edited by sunjl1981 on 2013-1-6 22:02 What is the color of high-purity hydrochloric acid? Is it normal to be slightly yellow? The requirements for free chlorine of high-purity hydrochloric acid are 60PPm for qualified products according to the national standard and 20PPm for first-class products. Is this correct? What are your company's control metrics? My free chlorine is controlled at 15---25PPm, which I think is too high. How can I reduce the free chlorine? The iron content is relatively high, and it is basically stable at 3---5PPm. Can any experts help analyze the reason? # hcbbs
High-purity hydrochloric acid Industry standard for high-purity hydrochloric acid (HG/T 2778-1996) 1 Appearance: Colorless or slightly yellow transparent liquid 2 High-purity hydrochloric acid should meet the requirements in the table below: High-purity hydrochloric acid industry standard project indicators Total acidity of first-class qualified products (based on HCL) % ≥ 31.0 31.0 Calcium (based on Ca) mg/L ≤ 0.30 0.50 Magnesium (based on Mg) mg/L ≤ 0.07 0.20 Iron (based on Fe) mg/L ≤ 0.30 3.0 Evaporation residue mg/L ≤ 25.0 50.0 Free chlorine mg/L ≤ 20.0 60.0 China * * The Ministry of Chemical Industry of the Republic approved the implementation of free chlorine on January 24, 1996, on January 24, 1997. The main purpose is to control the excess hydrogen and increase the excess hydrogen under normal conditions of flame (automatic proportioning).
There has been discussion in this regard, and it may be due to the iron content. Normally, if the acid exceeds 0.5PPm, the appearance will be colored, and it is related to the amount of iron.
The yellowing of high-purity acid is due to the high iron content. Normal high-purity acid is colorless and as pure as water. The requirement for the iron content of the high-purity acid entering the tank is less than 300PPb. Of course, the lower the better. If the iron content of the high-purity acid provided by the poster reaches 3~5PPM, not only will the battery be unusable, but sales will also be affected. As for the reason why acid contains iron, there is a special post in Haichuan. You can check it out.
The lower the iron content should be controlled, the better
Personally, I think the high iron content is due to water absorption? Also, where was the sample taken? In a can or straight from the stove? If it’s a jar, congratulations, right? * * If the corrosion leaks, the furnace will be in even greater trouble.