Basic Evaluation of Phase Relation in a Phosphorus-Containing System Saturated with CaSiO3 at Elevated Temperatures for the Utilization of Steelmaking Slag and Sewage Sludge as Phosphorus Resources

Minerals

Hideki Tsuruoka¹  Chiho Watanabe²  Yu-ichi Uchida² 

[1] Faculty of Engineering, Nippon Institute of Technology, Saitama 345-0826, Japan;Graduate School of Engineering, Nippon Institute of Technology, Saitama 345-0826, Japan;

关键词: phosphorus;    phase relation;    CaSiO₃;    2CaO·SiO₂-3CaO·P₂O₅ solid solution;    steelmaking slag;    sewage sludge;   

DOI  :  10.3390/min12020266

来源: DOAJ

【 摘 要 】

In view of obtaining fundamental information on phosphorus recovery from steelmaking slag and sewage sludge, a laboratory experiment using the model specimen of a slag/sludge mixture prepared at 1573 K was carried out to investigate phase relation in a [CaO-SiO₂-P₂O₅]-based system. The triangular compositional region, comprising of apices CaO·SiO₂ (CS), 3CaO·P₂O₅ (C₃P), and 2CaO·SiO₂-3CaO·P₂O₅ solid solution (C₂S-C₃Pss), was considered with particular interest. In this region, using SEM-EDX observation it was found that solid saturated CS and the solid C₂S-C₃Pss with a relatively high phosphorus content can coexist. With the addition of Al₂O₃ or Fe₂O₃ to the same specimens, the liquidus phase appeared as a third phase; however, CS and C₂S-C₃Pss phases were still observed for up to 5mass% addition. The further addition of Al₂O₃ or Fe₂O₃ to 10mass% resulted in dissolution of the solid CS phase, although C₂S-C₃Pss remained as the phosphorus concentrated phase. These results show that phase equilibria based on the ternary system would be stable and be beneficial for phosphorus recovery.

【 授权许可】

Unknown