The finished acid changes color to pink
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The acid production in our company is carried out using flue gas from the processing of gold concentrate; the raw material is flotation gold concentrate. The process involves an air cooler, electrostatic precipitator, scrubber, washing tower, two-stage electrostatic fogging, and two-stage absorption. The system produces acid; acid of type 93 changes color more severely than that of type 98, and the change is more pronounced in the finished acid tanks than in the circulation tanks. After being sampled and placed in carbon steel, it turns pink after 3–5 days. Measures already taken: 1. Prevent the formation of nitrogen oxides in the system, which could lead to the creation of *ao acid radicals. 2. Improve dust removal efficiency. 3. Keep the inlet temperature of the drying tower below 36 degrees Celsius. 4. Reduce the temperature of the circulating acid. 5. Increase the liquid level in the tank containing the finished acid to prevent acid sludge from hitting the bottom of the tank. 6. If it is truly impossible to avoid this issue, potassium permanganate is used to oxidize and change the color of the problematic substances. After implementing these measures, improvement is only achieved to a certain extent; when samples are taken from the tank containing the finished acid and placed in carbon steel, a pink color still appears around them. I wonder if anyone has any other effective methods to address this problem or to prevent it from occurring
Try adjusting the electric demisting voltage; if the demisting effect permits, lower it appropriately to see the result. By the way, check the pressure drop of the absorber demister
We have experienced this phenomenon as well, and we still haven’t found the reason
Don’t believe it – claims about excessive nitrogen oxides are complete nonsense. It says the selenium level is too high. . I can recycle your weak acid precipitation sludge. 379543433QQ
The reason for the solution was to debug the electric demister and the absorption tower. When selenium levels are too high, arsenic levels in your acids will definitely be too high as well.
When a slight redness appears, the selenium content exceeds 0.05%.