Reason for the red color change in An sulfate product
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Our factory uses the spray-type saturator process to produce sulfuric acid. Recently, for unknown reasons, the color of the ammonium sulfate mother liquor turned red; the color of the fresh ammonium sulfate product was normal, but it turned red after being exposed to air for some time. What is the exact cause of this? I hope experts can give some advice!
When the iron ion concentration is high, upon contact with air, the iron ions change from ferrous iron to ferric iron.
The influence of iron ions should be taken into consideration, as well as whether there are any new equipment or processes added. Additionally, the impact of entrainment during the desulfurization process before the saturator needs to be considered
Check the quality of the sulfuric acid raw material – is it red in color, indicating the presence of iron ions?
If the gas contains 200 mg/m3 of tar and 1000 mg/m3 of naphthalene, will this cause the color of the ammonium sulfate product to turn red?
Is it that high? The electric precipitator and pre-cooler aren’t operating properly; usually, the value is below 50
Potassium ferrocyanide K3 (common name: prussiate)
Whether it is the new start of desulfurization, or adjustments to the temperature of the gas and desulfurization liquid in the desulfurization section, the issue of liquid presence in the desulfurization process needs to be taken into account.
It is possible that desulfurization liquid has entered, causing the cobalt chloride used in the synthesis of PDS to turn red upon contact with air. The reactive oxygen species carried by PDS can also oxidize iron ions.