Inorganic Chemicals Industry ›› 2025, Vol. 57 ›› Issue (1): 83-89.doi: 10.19964/j.issn.1006-4990.2024-0154

• Environment·Health·Safety • Previous Articles     Next Articles

Research on Na2CO3 enhanced food additive wastewater hydrothermal wet reduction and detoxification of chromite ore processing residue

WEN Huizi(), XI Luyao, HE Shuyu, TAN Shanyi, ZHANG Liwen, CHEN Shaohua(), DU Yaguang   

  1. College of Resources and Environment,South-Central Minzu University,Engineering Research Center for Heavy Metal Pollution Control of Hubei Province,Wuhan 430074,China
  • Received:2024-03-18 Online:2025-01-10 Published:2025-01-24
  • Contact: CHEN Shaohua E-mail:wenhuizi1024@163.com;shaohuachen@mail.scuec.edu.cn

Abstract:

Chromite ore processing residue(COPR) is an industrial waste generated during the production of chromium and chromium salts,which contains a large amount of highly toxic Cr(Ⅵ).If COPR enters the environment,it will cause great harm to human beings and ecosystems.Na2CO3 as replacement solution enhanced the reducing substances in food additive wastewater hydrothermal wet reduction and detoxification of calcium-free roasted COPR was proposed in this paper.The process parameters such as food additive production wastewater dosage,reaction temperature and other conditions on the detoxification of COPR were investigated.The results showed that when the mass ratio of food additive production wastewater to COPR was 6∶100 (0.24 g for wastewater,4.0 g for COPR),temperature was 120 ℃,Na2CO3 concentration was 0.6 mol/L and reaction time was 3 h,Cr(Ⅵ) concentration in filtrate was 0.24 mg/L,which was lower than the limit value of 0.5 mg/L in “Integrated Wastewater Discharge Standard”(GB 8978—1996).And leaching concentration of Cr(Ⅵ) in detoxified COPR was 0.13 mg/L,which was lower than the pollution control limit of 0.5 mg/L in “Environmental protection technical specifications for pollution treatment of the Chromium residue”(HJ/T 301—2007) for COPR used as road base material and concrete aggregate,so it could be comprehensively utilized as concrete aggregate.The detoxification mechanism indicated that CO32- replaced Cr(Ⅵ) in COPR,accelerating the mass transfer of Cr(Ⅵ) from solid to liquid phase,and then the reducing substances such as glucose in food additive production wastewater reduced Cr(Ⅵ) in the solution to Cr(Ⅲ),achieving the goal of detoxifying COPR.

Key words: COPR, Cr(Ⅵ), food additive production wastewater, hydrothermal wet detoxification

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