Characteristics and aluminum reuse of textile sludge incineration residues after acidification.

The chemical composition and aluminum speciation of sludge incineration residue (SIR) were determined. Cementation of aluminum from sulfuric acid solution using SIR was studied. The results showed that acid-soluble inorganic aluminum was the predominant component in the sludge, and the total leached aluminum increased from 62.2% to 92.9% after incineration. Sulfuric acid dosage and reaction time were found to affect aluminum recovery positively. Conversely, the increase in temperature significantly inhibited recovery reactions. The optimized leaching condition was 1.66 g sulfuric acid per gram of SIR with a reaction time of 3 hr at 20 degrees C, resulting in the highest aluminum leaching rate of 96.7%. Compared to commercial aluminum sulfate solution coagulants, the leaching solution demonstrated higher COD(Cr), turbidity and color removal efficiency for textile wastewater.