COMPLEX FERTILIZER COMPOSITION AND METHOD FOR PREPARING SAME Russian patent published in 1997 - IPC

FIELD: production of sustained-action organomineral fertilizers capable of restoring humus and microelements contents in soil. SUBSTANCE: proposed fertilizer has following composition, wt. %: phosphorites 20.0-40.0, sands containing quartz and glauconite mineral 10.0-30.0, lignite being balance. Fertilizer is produced by mixing together naturally occurring phosphorites, quartz-glauconite sands and lignite ground to particle size 50-80 mcm, weight ratio of lignite: phosphorites: sands being equal to 6-8:1.5-2.5:0.7-1.2. Mixture thus-obtained is wetted to residual moisture content 28%, plasticized by addition of clay and granulated. Granules are dried at temperature at most 80 C to residual moisture content 14%, followed by calibration. EFFECT: good-quality fertilizer produced from readily available, cheap raw materials. 4 cl, 2 tbl