Distribution and enrichment of phosphorus in solidified BOF steelmaking slag

Abstract

The distribution of P in basic oxygen furnace steelmaking slag was investigated together with the enrichment behaviours of P in slowly cooled slag samples modified by SiO 2 from high temperature remelts at 1873 K. The slag microstructures were characterised, and the results showed that only a limited fraction of P 2 O 5 was dispersed in the matrix, whereas a large amount of P 2 O 5 was found to form solid solutions with dicalcium silicate (2CaO.SiO 2 or C 2 S) phase and/or with tricalcium silicate (3CaO.SiO 2 or C 3 S) phase in original industrial slag. It was also found that when the basicity (C/S5CaO/SiO 2 ) of slag modified by SiO 2 was close to 3, the main phase was C 2 S, and most of the P in the modified slag was precipitated from solid solution in the C 2 S. The mechanism of P enrichment is also discussed.

Influence of SiO2modification on phosphorus enrichment in P bearing steelmaking slag

“…The generation reaction of nC 2 S-C 3 P solid solution in P bearing slag is as follows 2CaOzSiO 2~C a 2 SiO 4 (1) During slag cooling, Ca, Si and O are first precipitated as nCaO.SiO, Ca 2 SiO 4 and Ca 3 (PO 4 ) 2 phase can be dissolved with each other in any proportion. The enrichment effect depends on the generation of nC 2 S-C 3 P solid solution.…”

Microwave-Supported Leaching of Electric Arc Furnace (EAF) Slag by Ammonium Salts

“…Given that the calcium ferroaluminates in the slag residue leached by ammonium chloride solution still contain relatively high contents of calcium, it shows that the calcium in the form of calcium ferroaluminates is difficult to extract. Moreover, as the phosphorus is mainly dissolved in C2S and C3S in the steelmaking slag [28,29], the leached slag residue particles containing phosphorus, probably the calcium silicates before leaching, have high levels of silicon and less amounts of iron and calcium, which indicates that most of the calcium has been leached from C2S and C3S phases by ammonium chloride solution. The SEM results are consistent with the XRD analysis.…”

Isothermal Enrichment of P-Concentrating Phase from CaO–SiO₂–FeO–MgO–P₂O₅ Melt with Super Gravity

“…The enrichment mechanism of phosphorus in steelmaking slag has been widely studied, [3][4][5][6] which indicated that phosphorus mainly enriched in dicalcium silicate phase in the form of solid solution as P-concentrating phase. According to these investigations, many researches on enhancing the phosphorus solubility in the P-concentrating phase have been carried out by modifying steelmaking slag with different additives such as Al 2 O 3 , 7,8) SiO 2 , 9) CaF 2 , 10) and TiO 2 .…”