NITROGENOUS HUMIC FERTILIZERS BY AMMONIATION OF HUMIC MATERIAL OBTAINED FROM KRAFT BLACK LIQUORS

Humic materials obtained from kraft black liquor were ammoniated with aqueous ammonia in a stainless-steel batch reactor. The effects of different variables, viz. total acidity of the humic material, reaction temperature and ammonia concentration, on the extent of N fixation by the humic material is reported. A 2(3) factorial design was used for the experiments. Results show that products containing up to 11.8 wt% total N can be obtained. The optimum operating conditions in order to obtain a high nitrogen content are: acidity 60 mL NaOH g-1 of sample; temperature 100-degrees-C; and aqueous ammonia concentration 8 wt%.