Lead recovery from PbZrO3 using wet ball-mill technique and hydrothermal synthesis of alpha-zirconium phosphate from wastewater for resource recovery

Lead recovery from lead zirconate (PbZrO(3)) ceramics was investigated using a wet ball-mill treatment in H(2)SO(4) aqueous solution. Subsequently crystalline alpha-zirconium phosphate (alpha-Zr(HPO(4))(2).H(2)O) was synthesized using a hydrothermal technique in order for the resource recovery of zirconium in the wastewater after the wet ball-mill treatment. A wet ball-mill treatment in 4.5M H(2)SO(4) aqueous solution for 24h was capable of converting more than 99.9% of the Pb initially included in the PbZrO(3) to solid state PbSO(4) with a purity of 98%. On the other hand, the Zr in the PbZrO(3) was dissolved into the acidic solution during the treatment. The Pb and Zr metal elements coexisting in PbZrO(3) were successfully separated by the wet ball-mill technique. Then, resource recovery of zirconium in the wastewater was examined. Crystalline alpha-Zr(HPO(4))(2).H(2)O was synthesized by hydrothermal treatments in 3.1-12.5M H(3)PO(4) aqueous solutions at temperatures of 120-240 degrees C for a duration of 70h. The hydrothermally prepared powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and then they were also evaluated in terms of cation exchange capacity (CEC) measurement and thermogravimetric (TG) analysis.