Chemical phosphorus recovery from waste fish bones ash by acidic leaching

Abstract

The worldwide phosphorus demand is increasing gradually, however phosphate ores are not renewable. Specifically, organic wastes contain large amounts of phosphorus that are not utilized properly. The phosphorus content in the fish bone ash represents around 17 wt.%. The potential of phosphorus recovery from waste fish bone ash by chemical dissolution was investigated in this study. Different amounts and concentrations of sulfuric acid (H2SO4) was applied to determine the optimum condition of phosphorus extraction. More than 98% of phosphorus was recovered using 2 M H2SO4 and an acid amount of 1.5 kg H2SO4/kg ash. In addition, the effect of reaction time on phosphorus dissolution was investigated. The results showed that complete ash dissolution could be accomplished after 90 min. The present investigation revealed that it is worthwhile to recover phosphorus from fish bone ashes, which could significantly benefit further applications that require pure phosphorus addition.