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Updated: Jul 19, 2026
11:14
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
Phosphorus removal characteristics in hydroxyapatite crystallization using converter slag.
Eung-Ho Kim1, Hwan-Kook Hwang, Soo-Bin Yim
1School of Urban and Civil Engineering, Hongik University, Seoul, Mapogu, Republic of Korea.
Summary
Converter slag effectively removes phosphorus via hydroxyapatite (HAP) crystallization. A slag column reactor achieved over 90% phosphorus removal, maintaining effluent concentrations below 0.5 mg/L.
Area of Science:
- Environmental Chemistry
- Materials Science
- Chemical Engineering
Background:
- Converter slag, a byproduct of steel manufacturing, presents an opportunity for resource recovery.
- Phosphorus pollution is a significant environmental concern, necessitating efficient removal methods.
- Hydroxyapatite (HAP) crystallization is a viable pathway for phosphorus sequestration.
Purpose of the Study:
- To investigate phosphorus removal using converter slag as a seed for HAP crystallization.
- To evaluate the performance of a slag column reactor system for continuous phosphorus removal.
- To determine the influence of various ions (Mg2+, F-, Fe2+) and alkalinity on HAP crystallization.
Main Methods:
- Batch reactor experiments to assess the effects of alkalinity, magnesium, fluoride, and iron on HAP crystallization.
- Column reactor operation over 414 days to evaluate long-term phosphorus removal efficiency.
- Analysis of crystalline material using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS).
Main Results:
- Phosphorus removal efficiency in batch tests increased with iron and fluoride concentrations but decreased with alkalinity and magnesium.
- The slag column reactor demonstrated high and stable phosphorus removal (average 90.4%) over 414 days.
- Effluent phosphorus concentration in the column reactor was consistently below 0.5 mg/L.
- XRD, FTIR, SEM, and EDS confirmed the formation of HAP with a Ca/P molar ratio of 1.72 on the converter slag seed particles.
Conclusions:
- Converter slag is a suitable seed material for HAP crystallization, enabling efficient phosphorus removal.
- The slag column reactor system is effective for sustainable and stable phosphorus elimination from wastewater.
- Optimizing conditions like ion concentrations is crucial for maximizing phosphorus removal efficiency.
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