| abstract |
A process for the preparation of a slow-release fertilizer comprising the steps of: n (a) grinding a first volume of peanut hulls to a particle size of 1/32 to 1/4 inch and a second volume to 1/8 to 1/2 inch, n (b) treating said first a volume of hulls with an equal volume of 2N (normal) nitric acid for 30 minutes at 121 degrees C. and 15 p.s.i. pressure to extract and solubilize the liqueous material from the hulls, n (c) adding 1 volume of 1 normal solubilized sodium hydroxide to 2 volumes of said second volume of peanut hulls and heating and stirring said mixture until said nutrients are solubilized, n (d) heating said second volume of peanut hulls and sodium hydroxide with steam and at a temperature of 121 degrees C. and pressure of 15 p.s.i. for 30 minutes to open the fibers of said hulls, n (e) adding fertilizer nutrients, such as commercially available potash or other source of potassium, super phosphate or other source of phosphate and ammonium nitrate or other source of nitrogen, to liquid waste material from the beer brewing industry containing either live or autolyzed yeast or other biological waste material, n (f) drying said heat-treated peanut hulls, whereby the fibers of the hulls close, entrapping said nutrients and said waste material, n (g) soaking said dried, impregnated hulls with the lignin-containing liquid from step (b), and n (h) drying the peanut hulls. n In another embodiment, the biological waste material is added to the peanut hulls as a solubilizing liquid with the sodium hydroxide in step (c), and the fertilizer nutrients are added only after the heat treatment is completed. n Also, a slow-release fertilizer comprising comminuted peanut hulls, impregnated with yeast-containing or other biological waste materials and inorganic nutrients and coated with lignin derived from peanut hulls by solubilizing with 2N nitric acid. The nutrients are only released to the soil on decomposition of the peanut hulls. |