| 摘要 |
<p>1,189,398. Fertilizers. SUMITOMO CHEMICAL CO. Ltd. 1 July, 1968 [1 July, 1967], No. 31336/68. Heading C1B. An NK fertilizer containing 20-90% of urea, 2-50% of potassium chloride and 5-40% of calcium sulphate is produced by spraying a molten mixture having the same composition as the desired product, except that it contains 0-40% of calcium sulphate and 1-10% of water, on to recycle material, optionally together with one or more of urea, potassium chloride and calcium sulphate, in a rotary granulating drum. The water may be supplied separately, in admixture, or as water of crystallization. The mole ratio of urea to gypsum in the product may be 4-7 : 1. The molten mixture may have a temperature of 90-130‹ C. and may be sprayed at a pressure of 0À1-5À0 kg/cm.<SP>2</SP> gauge. Granulation may be effected at a temperature of 50-100‹ C. for a period of 3-20 minutes. The water content of the material being granulated is preferably 1-2%. The hot granulated product may be mixed with further recycle material and cooled in a current of cold air in a further rotary drum. A total of 50-90% of recycled material (based on the total product) may be employed. Of this amount, 10-40% may be employed in the cooling step. The desired product may have a particle size of 6-12 mesh.</p> |
