Distribution of P2O5 between solid solution and liquid phase in dephosphorization slag of CaO–SiO2–FeO–P2O5–Na2O system

• Published in: Journal of iron and steel research, international international, 2019-11, Vol.26 (11), p.1162-1170
• Main Authors: Du, Chuan-ming, Lv, Ning-ning, Su, Chang, Liu, Wei-ming, Yang, Jin-xing, Wang, Hai-chuan
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; Engineering; Machines; Manufacturing; Materials Engineering; Materials Science; Metallic Materials; Original Paper; Physical Chemistry; Processes
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1007/s42243-018-00224-4

A multi-phase slag containing Na 2 O is potential to efficiently dephosphorize high-P hot metal. After dephosphorization, the generated slag with high P 2 O 5 content is regarded as a P resource. Because P 2 O 5 was mainly concentrated in the 2CaO·SiO 2 –3CaO·P 2 O 5 solid solution, the recovery of P from dephosphorization slag primarily depends on the separation of the solid solution from other phases. The distribution ratios of P 2 O 5 between solid solution and liquid phase in the CaO–SiO 2 –FeO–P 2 O 5 –Na 2 O slag system were investigated. The results indicated that the addition of Na 2 O facilitated the enrichment of P 2 O 5 in the solid solution because it increased not only the distribution ratio of P 2 O 5 but also the mass fraction of the solid solution. The distribution ratio of P 2 O 5 was independent of the P 2 O 5 content in slag. A higher P 2 O 5 content in slag resulted in higher P 2 O 5 and Na 2 O contents in the solid solution. The distribution ratio of P 2 O 5 increased with the total Fe content in the liquid phase, regardless of the valence of Fe. An increase in the FeO content in slag brought a higher P 2 O 5 content in the solid solution. As slag basicity increased, the distribution ratio of P 2 O 5 increased, but the P 2 O 5 content in the solid solution decreased.