Search results for "EDTA chelation"
showing 2 items of 2 documents
Selective recovery of phosphorus as AlPO4 from silicon-free CFB-derived fly ash leachate
2018
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 con…
Beneficiation, desilication and selective precipitation techniques for phosphorus refining from biomass derived fly ash
2018
The supply of affordable phosphorus (P), a biocritical element, is at great risk due to the utilization of limited natural phosphate minerals at an unprecedented scale. The need of phosphorus recovery to sustain the anthropogenic P-cycle was recog- nized and fly ash, a waste product from the combustion of renewable biofuels, was selected as the secondary resource. Increasing supply of fly ash in the future due to growing use of forest biofuels in energy production also contributes to its suitability for P-recovery. Fly ash comprises of silicates, oxides, carbonates, phosphates and hydroxides of the elements that potentially represent the entire periodic table. This only augments the complexity…