Phosphorus Removal Characteristics in Hydroxyapatite Crystallization Using Converter Slag

• Published in: Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering Toxic/hazardous substances & environmental engineering, 2006-11, Vol.41 (11), p.2531-2545
• Main Authors: KIM, EUNG-HO, HWANG, HWAN-KOOK, YIM, SOO-BIN
• Format: Article
• Language: English
• Subjects: Alkalies; Alkalinity; Converter slag; Crystallization; Durapatite - chemistry; Effluents; Fluoride; Fluorides; Fourier transforms; Hydrogen-Ion Concentration; Hydroxyapatite; Hydroxyapatite crystallization; Iron; Iron and steel making; Magnesium; Mapping; Metallurgy; Microscopy, Electron, Scanning; Particulates; Phosphorus; Phosphorus - chemistry; Phosphorus - isolation & purification; Phosphorus removal; Q1; Reactors; Seed crystal; Seeds; Slags; Spectrometry, X-Ray Emission; Spectroscopy, Fourier Transform Infrared; Steel converters; Time Factors; X-Ray Diffraction; X-ray spectroscopy
• ISSN: 1093-4529; 1532-4117
• DOI: 10.1080/10934520600927740

This study was performed to investigate the phosphorus removal characteristics in hydroxyapatite (HAP) crystallization using converter slag as a seed crystal and the usefulness of a slag column reactor system. The effects of alkalinity, and the isomorphic-substitutable presence of ionic magnesium, fluoride, and iron on HAP crystallization seeded with converter slag, were examined using a batch reactor system. The phosphorus removal efficiencies of the batch reactor system were found to increase with increases in the iron and fluoride ion concentrations, and to decrease with increases in the alkalinity and magnesium ion concentration. A column reactor system for HAP crystallization using converter slag was found to achieve high, stable levels of phosphorus elimination: the average PO 4 -P removal efficiency over 414 days of operation was 90.4%, in which the effluent phosphorus concentration was maintained at less than 0.5 mg/L under the appropriate phosphorus crystallization conditions. The X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra of the crystalline material deposited on the seed particles exhibited peaks consistent with HAP. Scanning electron micrograph (SEM) images showed that finely distributed crystalline material was formed on the surfaces of the seed particles. Energy dispersive X-ray spectroscopy (EDS) mapping analysis revealed that the molar Ca/P composition ratio of the crystalline material was 1.72.