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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2024, Vol. 43 ›› Issue (6): 2206-2216.

• Solid Waste and Eco-Materials • Previous Articles     Next Articles

Effect of Composite Fluxing Agent on Melting Temperature and Phase of Fly Ash from Waste Incineration

LU Fanjie1, LI Changcheng2, YE Jiayuan1, LIU Qiming3   

  1. 1. China Building Materials Academy Co., Ltd., Beijing 100024, China;
    2. Technical Supervision & Research Center for China Building Materials Industry, Beijing 100024, China;
    3. Zhejiang Helihaike New Material Co., Ltd., Jinhua 321100, China
  • Received:2023-11-24 Revised:2024-02-11 Online:2024-06-15 Published:2024-06-18

Abstract: High temperature melting vitrification is the safest and harmless disposal technology for fly ash from hazardous waste incineration. Fly ash with high calcium content was used as the research object to melt fly ash with low temperature by introducing SiO2, H3BO3 and CaF2 fluxing agents. The melting temperature, phase change and heavy metal leaching of fly ash were characterized by X-ray diffractometer, ash melting point analyzer and inductively coupled plasma atomic emission spectrometer. The results show that when the alkalinity of fly ash is adjusted to 1.10 by SiO2 (27.9%, mass fraction), CaSiO3 minerals with low melting point are formed, and the melting point of fly ash decreases from above 1 400 ℃ to 1 300 ℃. H3BO3 (4.5%, mass fraction) and CaF2 (7.0%, mass fraction) are introduced as fluxing agents, and the melting temperature is further reduced to 1 200 ℃, but SiO2 is overdoped. After optimization, the composite fluxing agent formula is SiO2 (20.0%, mass fraction), H3BO3 (4.5%, mass fraction) and CaF2 (7.0%, mass fraction), and the minimum melting temperature of fly ash is 1 124 ℃, the vitreous content of the melt product reaches 87% (mass fraction), and the harmful substances of acid leaching are lower than the limit value, meeting the technical requirements of GB/T 41015—2021 standard for vitrification products.

Key words: waste incineration fly ash, fluxing agent, low-temperature melting, alkalinity, vitreous content

CLC Number: