Exploded biomass based slow-release fertilizer

Abstract

A fertilizer product comprising an acid-carbonized microporous matrix derived from expanded biomass and a fertilizer reaction product of residual acid from the carbonizing process and at least one added fertilizer precursor. The biomass may include steam exploded wood powder. The expanded biomass may be carbonized with a combination of sulphuric and phosphoric acids, followed by ammoniation to produce ammonium sulphate and mono- or diammonium phosphate. The fertilizer reaction product adsorbs onto the carbon matrix, which results in a slow-release when the material is applied to the soil.

What is claimed is: 
     
         1 . A fertilizer product comprising an acid-carbonized microporous matrix derived from expanded biomass and a fertilizer reaction product of residual acid from the carbonizing process and at least one added fertilizer precursor. 
     
     
         2 . The fertilizer product of  claim 1  wherein the residual acid comprises sulphuric acid, phosphoric acid, or both sulphuric and phosphoric acid. 
     
     
         3 . The fertilizer product of  claim 1  wherein the fertilizer reaction product comprises one or more of ammonium sulphate, monoammonium phosphate, diammonium phosphate, ammonium nitrate, potassium sulphate, potassium nitrate, potassium phosphate, potassium sulphite or potassium sulphide. 
     
     
         4 . The fertilizer product of  claim 1  further comprising a micronutrient 
     
     
         5 . The fertilizer product of  claim 4  wherein the micronutrient comprises one or more of Mg, Cu, Zn, Fe, B, Mn, or Mo. 
     
     
         6 . The fertilizer product of  claim 1 , comprising a portion of immediately available fertilizer reaction product and a portion of carbon-bound slow-release fertilizer reaction product. 
     
     
         7 . An intermediate product for producing a fertilizer product, comprising:
 (a) an acid-carbonized microporous matrix derived from expanded biomass, having an available pore volume; and   (b) a residual acid from the carbonizing process impregnated in the pore volume, in an amount less than 71% by weight of the intermediate product.   
     
     
         8 . The intermediate product of claim  13  wherein the residual acid is impregnated in the pore volume in a volume occupying less than 80% of the available pore volume. 
     
     
         9 . The intermediate product of claim  14  wherein the residual acid occupies less than about 70% of the available pore volume. 
     
     
         10 . The intermediate product of claim  15  wherein the residual acid occupies than about 60% of the available pore volume. 
     
     
         11 . The intermediate product of claim  13  wherein the residual acid is present in an amount less than about 60% by weight. 
     
     
         12 . The intermediate product of claim  17  wherein the residual acid is present in an amount less than about 50% by weight.