Extraction of Phosphorus and Recovery of Phosphate from Steelmaking Slag by Selective Leaching

Numerical Study into Gravity Separation of Phosphorus from BOS Slag during Solidification

“…For this cooling rate, all three models confirm the possibility of the particle floating from the bottom to the top of the crucible, with the minimum floating distance of ~3.8 mm predicted by Eq. (14). The SEM and energy dispersive x-ray spectroscopy (EDS) analysis of crucibles from the experiments shows the presence of coarse dendritic crystal structures in the upper section of the crucible, and finer crystals in the lower section (Fig.…”

“…4,[7][8][9] This process cannot recover the phosphorus and is limited by the high energy cost of grinding. Removing phosphorus by leaching has been extensively investigated in the literature, [10][11][12][13][14] and to be effective if the slag was cooled with a very low cooling rate (~5 K/ min or less) and crushed into small size (order of ~50 μm). These conditions may restrict the use of acid leaching on an industrial scale.…”

“…To determine the rising distance of a single floating crystal particle, the velocity expressions in Eqs. (11), (12) and (14) were separately integrated using the temperature dependent viscosity parameter wherein the slag's temperature was obtained by solving the heat balance expressions given in Eqs. (1) and (4).…”

Segregation of a Phosphorus Rich Phase During Differential Solidification of BOF Slag

“…[3,4] The conventional technique of magnetic separation of the Fe-rich phase involves the high energy cost of grinding. [5][6][7][8] Acid leaching for removing the P-rich phase [9][10][11] requires energy intensive conditions such as crushing/grinding and low cooling rate presenting economical restrictions to its industrial application. Separation due to gravity by floating of the C 2 S-C 3 P crystals was shown possible under a low cooling rate of below 2 °C/m [8,[12][13][14] which could only be implemented under controlled cooling.…”

Enrichment of Phosphorus from Iron Ore to Dicalcium-silicate Phase by Partial Reduction

“…Such a slag is being actively used as a multiphase flux. [11][12][13][14][15][16] The C 2 S-C 3 P s.s. phase is soluble in water and Teratoko et al, 17) Numata et al, 18) and Iwama et al 19) have reported the possibility of dilute acid leaching of P from slag. Kubo et al proposed a process in which C 2 S-C 3 P s.s. -containing slag is converted into free particles by electrical pulse disintegration and then the P concentrate is sorted using a strong magnetic field.…”