Content, modes of occurrence, and significance of phosphorous in biomass and biomass ash

The global scarcity, demand, prices and quality of rock phosphate seem to be ones of the greatest challenges in future related to food and feed security, as well as manufacture of critical phosphorous (P) materials in industry. Alternative P resources are required to substitute the finite phosphate rocks. An extended overview on the content, association, modes of occurrence, and significance of P in biomass and biomass ash (BA) was conducted based on reference and our own chemical, phase-mineralogical, thermal and leaching data. Phosphorous is highly enriched in different biomass types and especially in their BAs. Phosphorous contents in biomass are variable (0.01-5.0%, mean 0.2%) and it occurs in fluid, organic and inorganic matter of biomass such as min-eralised aqueous solution, various organic forms, and different Ca, K, Mg and Fe phosphates. The leached water-soluble proportions of P from biomass are substantial (4-97%, mean 51%). P2O5 is highly enriched in BA as its concentrations are also highly variable, namely 0.2-37.5% (mean 4%). The modes of P occurrence in BA include more than 60 mostly alkaline-earth and alkaline phosphates. In contrast to biomass, the water-soluble P pro-portions of BA are limited (0-15%, mean 2.3%) due to the formation of less mobile P phases. Different tech-nological and environmental advantages and disadvantages are related to the content and particularly specific modes of occurrence of P in biomass and BA and they are described and evaluated. Phosphorous in biomass and BA is a huge alternative and prospective resource that can substitute the phosphate rocks in future.

Automated summary

The global scarcity, demand, prices and quality of rock phosphate pose significant challenges for food and feed security, as well as industrial phosphorous production. Alternative sources of phosphorous are needed to replace finite phosphate rocks. A comprehensive study on the content, association, modes of occurrence, and significance of phosphorous in biomass and biomass ash was conducted. Phosphorous is highly enriched in biomass and particularly in biomass ash. The water-soluble proportions of phosphorous leached from biomass are substantial, while in biomass ash, the water-soluble proportions are limited due to the formation of less mobile phosphorous phases. Different technological and environmental advantages and disadvantages are associated with the content and modes of occurrence of phosphorous in biomass and biomass ash.