The reason for the red coloration of ammonium thiocyanate

Thread Content

A few days ago, in our plant’s desulfurization and salt extraction process, the ammonium thiocyanate turned red suddenly. The salt extraction company said that this was caused by an excess of hydroquinone, but our plant did not add any more hydroquinone suddenly. In fact, no waste liquid has been discharged for almost a month now since the start of the salt extraction process. Our plant has also started using less hydroquinone in the desulfurization process (by 1/3), yet the levels of hydroquinone in the desulfurization liquid tests have increased instead of decreasing. Later, once the color of ammonium thiocyanate returned to normal, we analyzed the decolorizing solution in the salt-extraction and decolorization tank, and found that the hydroquinone content was higher when the color was normal compared to when ammonium thiocyanate turned red.