Effect of Thiourea on Lead Release from Lead-Bearing Jarosite under Freeze-Thaw Cycling

Lead is a toxic factor in jarosite residue, and it is important to study its release behavior from simulated lead jarosite residue (LSJ) to predict the stability of the jarosite residue and its impact on the environment. This study investigated the ion release behavior, leaching toxicity, stability, and ion migration of LSJ during freeze-thaw cycling with thiourea (T-FTC). The release of lead, iron, and sulfate radicals from lead jarosite via T-FTC was influenced by several factors. Under specific conditions, the amount of lead released was 6.09 mM/L, which accounted for 38.3% of the total lead. After the T-FTC treatment, the residual lead increased, and the leaching toxicity and long-term stable equilibrium concentration of lead were reduced to 42.1 mg/L and 12.4 mg/L, respectively, which decreased by 82% and 84%, respectively and led to improved environmental stability. This study provides a novel approach for the safe disposal of jarosite residue under low-temperature and mild conditions, and the results can be used to predict the stability of jarosite residue and its secondary pollution in the environment.