Recovery of phosphorus from sewage sludge ash by heat treatment and liquid-liquid separation

Mauricio Cordova Udaeta, Gjergj Dodbiba, Josiane Ponou, Keiichi Sone, Toyohisa Fujita

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Phosphorus is a scarce resource, some estimates predict a peak in production in the years to come; therefore, research efforts on methods to recycle the phosphate generated in urban sewage are increasing. Sewage Sludge Ash (SSA) arises as a promising source for Phosphorus Recycling. This research studies the use of a Heat Treatment, followed by liquid-liquid extraction in order to attain P205 recovery from SSA. The heat treatment was carried out using the addition of Ca(OH)2 and exposure to 1250° C for 30min, in order to form the P-bearing phase Silicocarnotite (Ca5(PO4)SiO4) and a phase similar to the non P-bearing phase Gehlenite (Ca2Al2SiO7). Preliminary experiments have shown that these mineral phases can be separated using a simple extraction using kerosene and a surfactant under controlled pH. When the actual SSA sample was heated this way and then subjected to extraction, a maximum difference of 39% in P2O5 content was obtained at pH = 2 when 0.25% Dodecyl Amino Acetate (DAA) is used as surfactant.

Original languageEnglish
Pages (from-to)93-97
Number of pages5
JournalInternational Journal of the Society of Material Engineering for Resources
Issue number1
Publication statusPublished - 2018 Mar
Externally publishedYes


  • Heat treatment
  • Liquid-liquid separation
  • Phosphorus recovery
  • Sewage sludge ash

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Mechanical Engineering


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