Technology for selective removal of chromium ions under acidic conditions
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Dear experts, please offer your help! The waste dilute sulfuric acid resulting from the pickling of steel at 3-5% concentration contains various metal ions; ferrous ions are precipitated as a by-product. However, the chromium ion concentration of 1100 ppm far exceeds the **standard. Are there any effective processing techniques that can remove or partially remove these 1100 ppm of chromium ions? Thank you! ! ! ! ! ! ! 740464410
In such cases, an alkali is used to raise the pH to 4.5; ferrous ions remain in the water, while Cr dissolves out. Filter and then recrystallize. It is recommended to treat the original solution with reduced iron powder first, to ensure that the ferrous ions in the solution are not oxidized to the +3 valence state.