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NH 4 Cl selective leaching of basic oxygen furnace slag: Optimization study using response surface methodology
Author(s) -
Sun Yong,
Zhang Jing Ping,
Zhang Lian
Publication year - 2016
Publication title -
environmental progress and sustainable energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.495
H-Index - 66
eISSN - 1944-7450
pISSN - 1944-7442
DOI - 10.1002/ep.12365
Subject(s) - leaching (pedology) , response surface methodology , central composite design , magnesium , oxygen , chemistry , basic oxygen steelmaking , selective leaching , analytical chemistry (journal) , metallurgy , materials science , dissolution , chromatography , steelmaking , soil water , soil science , geology , organic chemistry
The basic oxygen furnace slag (SL) was selectively leached by NH 4 Cl. Response surface methodology and the central composite design (CCD) were employed in determining the optimal condition. The process parameters such as leaching duration, NH 4 Cl concentration, liquid solid ratio (LSR), and leaching temperature were chosen as independent variables in CCD. The quadratic model was developed for process optimization and statistical experimental designs. It is found that the leaching duration, NH 4 Cl concentration and liquid solid ratio are significant to the extraction of Ca 2+ and Mg 2+ . The optimal conditions with setting maximum extraction of calcium and magnesium cations from SL are as following: 68 min (X 1 ), 1.8 mol/L NH 4 Cl (X 2 ), LSR 12 mL/g (X 3 ), 53°C (X 4 ), with the predicted Ca 2+ and Mg 2+ concentration reaching 13.3 and 3.2 g/L, respectively. The proposed simplified leaching mechanism indicates a two‐stage leaching. The prone leachable MgFe 2 O 4 and Ca 2 Fe 2 O 5 are extracted in the fast stage, while the extraction of CaO occurs throughout slow stage. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1387–1394, 2016