An eco-friendly approach for NaCl recovery from organic pollutants-containing waste salt by roasting together with low-grade pyrolusite

Abstract

A large amount of organic pollutants-containing waste salt is produced in chemical production process, which is usually filled or deposited without treatment, causing serious environmental pollution and a waste of salt resource. In this work, in order to reduce the emission of toxic and harmful gasses and make full use of the organic matter component in waste salt, pyrolusite was used as an absorbent in the process of high-temperature pyrolysis of waste salt, of which MnO 2 was reduced to MnO while absorbing harmful gasses. The dual effects of roasting to remove organic pollutants from the waste salt and increase manganese leaching efficiency were systematically investigated, and the roasting mechanism and process were explored. Co-recovery of NaCl from organic pollutants-containing waste salt and manganese from pyrolusite ore was achieved. The results indicated that the optimum the removal efficiency of organic matter in the waste salt could be reached 99.45%, the purity of recovered NaCl products was 99.83% and leaching efficiency of 99.62% for manganese under the mass ratio of waste salt to pyrolusite of 8:5, the co-roasting temperature of 650 °C, and the roasting time of 40 min. • Co-recovery of NaCl from waste salt and Mn from low-grade pyrolusite was realized. • Pyrolusite was used as an adsorbent to absorb toxic gasses reducing pollution. • The mechanism and process of co-recovery were investigated.