Effect of Na 2 O Addition on Phosphorus Dissolution from Steelmaking Slag with High P 2 O 5 Content

Chuan ming Du, Xu Gao, Shigeru Ueda, Shin ya Kitamura

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Slag with high P 2 O 5 content generated during the use of high-P iron ores is an important potential source of phosphate. Because the P-rich 2CaO·SiO 2 –3CaO·P 2 O 5 solid solution in the slag was preferentially dissolved compared with other phases in aqueous solutions, selective leaching of P from slag with high P 2 O 5 content was applied to recover soluble P in this study. To improve dissolution of the P-rich solid solution, the effects of Na 2 O addition on slag dissolution were investigated under different leaching conditions. The results show that a new 2CaO·SiO 2 –2CaO·Na 2 O·P 2 O 5 solid solution was formed in the slag after Na 2 O was added, resulting in a higher dissolution ratio of P. However, at pH 7, further increase in Na 2 O content did not promote P dissolution because of phosphate precipitation. At pH 5, a better P dissolution was obtained and its dissolution ratio increased with an increase in Na 2 O content, indicating that Na 2 O addition promoted the dissolution of the solid solution from slag. In the citric acid solution, more than 90% of the solid solution was dissolved and the dissolution of the matrix phase was suppressed dramatically by Na 2 O addition, leading to a low dissolution ratio of Fe. An excellent selective leaching of P from slag was achieved.

Original languageEnglish
Pages (from-to)671-682
Number of pages12
JournalJournal of Sustainable Metallurgy
Volume3
Issue number4
DOIs
Publication statusPublished - 2017 Dec 1

Keywords

  • Citric acid
  • Na O addition
  • Phosphorus recovery
  • Selective leaching
  • Steelmaking slag

ASJC Scopus subject areas

  • Environmental Science (miscellaneous)
  • Mechanics of Materials
  • Metals and Alloys

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