A few questions about adding acid to ferric chloride
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This post was last edited by sunjl1981 on 2013-1-6 20:27. I heard that when producing brine, some manufacturers will add acid to it when preparing ferric chloride. What should the PH of ferric chloride be? Is it redundant to add acid? # , , &
FeCl3 is a strong acid and weak alkali salt. When dissolved in water, Fe3+ hydrolyzes, making the solution acidic. The equation is as follows: FeCl3+3H2O==Fe(OH)3+3HCl, (reversible reaction) The purpose of adding hydrochloric acid is to destroy the hydrolysis balance and inhibit the occurrence of hydrolysis. The pH at which Fe(OH)3 begins to precipitate is 2.7, and the precipitation is completely at 3.7. To prevent hydrolysis and precipitation, the pH should be controlled below 2.7.
What you said above is correct. FeCl3 is a strong acid and weak alkali salt. When Fe3+ is dissolved in water, it will hydrolyze, making the solution acidic. The purpose of adding hydrochloric acid is to destroy the hydrolysis balance and inhibit hydrolysis. But it can be used immediately after preparation. Generally, there is no need to add acid.
The explanation on the second floor is very thorough, but what is the purpose of using ferric chloride in primary brine? It is necessary to produce Fe(OH)3 through hydrolysis. The adhesion properties of the Fe(OH)3 precipitate are used to bind the small magnesium hydroxide particles scattered in the brine into larger micelles, thereby forming floating mud removal.