The jarosite residue is a harmful byproduct of the zinc hydrometallurgical process and has been classified as hazardous waste due to its high content of heavy metals and poor stability. In this work, the recovery of valuable metals by synergistic disposal of jarosite residue with cement kiln has been investigated. A series of investigations were undertaken to assess the effect of amount of jarosite residue, roasting time, and the addition of CaCl2on phase transformation and migration of valuable elements in the cement clinker. When 25% of jarosite residue was added to the raw cement materials and roasted at 1400 °C for 30 min, the silicate content in the cement clinker reached 54.4%. In the presence of CaCl2as the mineralizer, the volatilization rates of Pb and Zn were 93% and 75%, respectively. The results indicated that jarosite residue can be used as the cement additive and valuable metals of Pb and Zn can be recovered simultaneously during the roasting process.Keywords:jarosite residue;cement;Pb and Zn;synergistic roasting
Spent pot-lining (SPL) and red mud (RM) are significant industrial solid wastes generated from the aluminum industry, holding valuable potential as secondary resources. This study addresses the pressing challenges of mitigating fluoride emissions resulting from the pyrometallurgical process of SPL and recovering iron (Fe) components from RM. To achieve these objectives, a synergetic reduction-stabilization process via co-calcination was proposed. During co-calcination, the carbonaceous content of SPL acts as a reducing agent, facilitating the reduction of Fe oxides in RM to magnetite (Fe 3 O 4 ). The recovered Fe 3 O 4 was efficiently separated through magnetic separation with 66.9% recovery efficiency. Additionally, the co-calcination process synergistically stabilizes fluoride emissions from SPL due to the presence of calcium oxide (CaO) in RM. This results in fluoride emissions reacting with CaO to form insoluble fluorite (CaF 2 ), leading to significantly reduced fluoride leaching concentrations (18.3 mg L −1 ), well below national recommended standards (100 mg L −1 ). Mineral transformations revealed that Na 3 AlF 6 from SPL decomposed into NaF, AlF 3 , and HF, with subsequent reactions with CaO leading to CaF 2 formation. The selectivity of element combinations among Ca-Fe-F-O can be attributed to the distinct ionic potentials in the HF-CaO-Fe 2 O 3 -C system, where CaF 2 arose from a hard acid (Ca(II))-hard base (F - ) interaction, and Fe 2 O 3 reduction was influenced by the weaker bonding between soft base O 2- and borderline acid Fe(III)/Fe(II) repulsion, according to the Hard-Soft Acid-Base (HSAB) theory. This proposed synergistic utilization approach not only detoxifies harmful fluoride emissions but also offers a sustainable method for Fe recovery, holding significant potential for environmental and economic benefits in the context of aluminum industry waste management practices.
危险品化学品经营许可证（带存储）