Inorganic Chemicals Industry ›› 2023, Vol. 55 ›› Issue (2): 106-112.doi: 10.19964/j.issn.1006-4990.2022-0218

• Environment·Health·Safety • Previous Articles     Next Articles

Research on heat treatment of NaCl-KCl waste salt in pesticide industry

ZHANG Sen1,2(),WAN Jun1,2,CHEN Tianhu1,2(),DONG Shiwei1,2,XU Liang1,2,LI Yaqian1,2,ZHAO Yueling1,2   

  1. 1. Key Laboratory of NanoMinerals and Pollution Control in Anhui Province,School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China
    2. Anhui Academy of Environmental Sciences,Hefei 230031,China
  • Received:2022-04-19 Online:2023-02-10 Published:2023-02-16
  • Contact: CHEN Tianhu E-mail:2020170807@mail.hfut.edu.cn;chentianhu@hfut.edu.cn

Abstract:

In order to achieve the purpose of turning hazardous waste into high value-added products,the combined methods of high temperature pyrolysis,dissolution purification,thermal evaporation crystallization and cooling crystallization were used to deal with the NaCl-KCl type waste salt in the pesticide industry,to obtain high-purity NaCl and KCl regenerated salt.The inorganic and organic components of waste salt were analyzed.The influence of atmosphere,temperature and holding time on the residual amount of TOC in waste salt after heat treatment and the pyrolysis process of organic matter were investigated.The optimal process parameters of NaCl-KCl type waste salt heat treatment were determined as follows:oxygen-free atmosphere,temperature above 500 ℃,holding for 10 min.Then thermal evaporation crystallization and cooling crystallization were separated to obtain sodium salt and potassium salt.The obtained pyrolysis carbon by-product ID/IG was 0.973,the average pore diameter was 4.00 nm,the total pore volume was 0.071 9 mL/g and the specific surface area was 35.96 m2/g.The TOC contents of purified NaCl and KCl regenerated salt were 42 and 189 mg/kg,respectively,and the removal rate of organic matter was over 99%.Sodium salt was expected to be used in the chlor-alkali industry and other fields,and potassium salts could be used to make potash fertilizers.It provided reference for the resource utilization of waste salt and the solution of waste salt encroachment by enterprises.

Key words: waste salt, pyrolysis, TOC, pyrolysis carbon, crystal separation

CLC Number: