Inorganic Chemicals Industry ›› 2025, Vol. 57 ›› Issue (8): 102-109.doi: 10.19964/j.issn.1006-4990.2024-0491

• Environment·Health·Safety • Previous Articles     Next Articles

Study on mechanism of preparation of porous ceramsite and fixation of heavy metal manganese from electrolytic manganese slag and multi-source solid waste

LIANG Qingyang1,2,3(), XUE Fei1,2,3, HUANG Xuquan1,2,3(), ZHAO Xiaorong1,2,3, WANG Haojie1,2,3, HAN Zilong1,2,3, WANG Jun1,2,3   

  1. 1.Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges University,Yichang 443002,China
    2.College of Hydraulic & Environmental Engineering,China Three Gorges University Yichang 443002,China
    3.Yichang Key Laboratory of Solid Waste Disposal and Resource Utilization(China Three Gorges University),Yichang 443002,China
  • Received:2024-09-10 Online:2025-08-10 Published:2024-11-25
  • Contact: HUANG Xuquan E-mail:LiangQY0605@163.com;huangxuquan@126.com

Abstract:

A lightweight porous ceramsite was successfully synthesized using electrolytic manganese residue(EMR) as the primary raw material,supplemented by municipal sludge,graphite tailings,and bentonite.The pore structure evolution mechanism of the ceramsite was investigated through advanced analytical techniques,including X-ray diffraction(XRD),stereomicroscopy,and Fourier-transform infrared spectroscopy(FT-IR).Additionally,the curing mechanism of Mn²⁺ was elucidated.The experimental results indicated that optimal conditions,determined via single-factor optimization,including a formulation comprising of 35% EMR and 35% sludge,25% of graphite tailings,a sintering temperature of 1 130 ℃,and a sintering duration of 15 minutes.Under these conditions,the resulting EMR-based ceramsite exhibited favorable physical properties:A bulk density of 651 kg/m³,an apparent density of 1 406 kg/m³,a compressive strength of 3.78 MPa,and a one-hour water absorption rate of 5.36%.During high-temperature sintering,the formation of liquid phase on the ceramsite surface effectively reduced water absorption.Internally,this liquid phase encapsulated gas bubbles,forming a closed-pore structure.The leaching behavior of Mn²⁺ was primarily attributed to MnSO₄ present in the EMR.The thermal decomposition of MnSO₄ was found to be reversible.CO and SO₂ gases trapped within the closed pores inhibited its decomposition,thereby influencing Mn2+ fixation.Furthermore,the presence of Fe₂O₃ from the sludge lowered the sintering temperature and promoted the formation of high-temperature liquid phases,which contributed to the retention of undecomposed MnSO₄.Consequently,increasing the EMR and sludge content from 35% to 45% led to an increase in Mn²⁺ leaching concentration from 0.33 mg/L to 0.84 mg/L.The immobilization mechanism of manganese involved both physical and chemical processes.Physically,the dense structure formed by the high-temperature liquid phase encapsulated Mn species.Chemically,Mn²⁺ participated in the formation of manganese-wollastonite and spinel-type ferrites under elevated temperatures,achieving effective chemical stabilization.This study not only significantly enhanced the utilization rate of EMR but also demonstrated a viable approach for the co-processing of multiple solid wastes into functional materials,offering practical insights and technical support for the resource recovery of large-volume solid waste.

Key words: electrolytic manganese residue, sludge, porous, ceramite, heavy metal solidification

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