6533b7d3fe1ef96bd1260029
RESEARCH PRODUCT
Selective recovery of phosphorus as AlPO4 from silicon-free CFB-derived fly ash leachate
Roshan BudhathokiAri VäisänenManu Lahtinensubject
AlPO4 precipitationpiiSilicon020209 energyphosphorus recoverychemistry.chemical_elementrauta02 engineering and technology010501 environmental sciencesRaw material01 natural sciencescomplex mixturesIndustrial and Manufacturing EngineeringironImpurity0202 electrical engineering electronic engineering information engineeringMaterials Chemistryrecovery (recapture)lentotuhkaLeachatephosphorusta116ta215fosfori0105 earth and related environmental sciencesPrecipitation (chemistry)Fe-EDTA chelationPhosphorusfungiMetals and Alloyssiliconfly ashfly ash utilizationchemistrytalteenottoReagentFly asherottaminen (tekniikka)Nuclear chemistrydescription
The prospect of phosphorus (P) recovery from siliceous fly ash was investigated. The phosphorus content in the pristine fly ash was 1.21%. Obtaining pure phosphorus products from fly ash is very challenging because of high concentration of other elements, silicon (Si) at 17.3% being the major contaminant. The fly ash was fractionated with sieve size of 125 μm to concentrate the phosphorus in the small-size fraction, which also facilitated the removal of 78% of silica (Si) in the solid phase. The fractionated fly ash was treated with 8 M HCl in order to remove 98% of Si by aging (5 h) of leachate until precipitation of Si-gel, and a phosphorus-rich solution is obtained. Iron (Fe) is also considered an impurity in the recovered P-product and its co-precipitation is prevented by the use of EDTA as Fe-masking reagent at [EDTA]/[Fe] ratio of 1. About 70% of Fe is retained in the solution during recovery of phosphorus with aluminum at pH 4. Amorphous white solid was recovered containing 18.08% P, this is 15 times high than that in the pristine fly ash used as raw material in this recovery process. peerReviewed
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-06-01 |