| 摘要 |
<p>1,142,288. Prilled NPK fertilizers. NORSK HYDRO - ELEKTRISK KVAELSTOFAKTIESELSKAB. 11 May, 1967 [18 Feb., 1967], No. 21994/67. Heading C1B. A fluid NP fertilizer containing 0-5% of water is mixed with a solid K fertilizer, more than 70% of which has a grain size of more than 0À1 mm., the mixture being maintained at pH 5-6À5 and prilled by spraying. The pH may be adjusted before or during mixing by the addition of ammonia, diammonium phosphate or magnesium oxide. The temperature during mixing may be 130‹ C. and the mixing time may be less than 2 minutes. The mixture may be sprayed in a centrifuge having orifices of 3-4 mm., the solid having a grain size of over 1 mm. The NP component may comprise ammonium phosphate and nitrate and may be produced by dissolving phosphate rock in nitric acid, removing solid calcium nitrate, neutralizing with ammonia, and evaporating water. Constituents of the K fertilizer may be potassium chloride, potassium sulphate, kieserite, sodium tetraborate, and recycled product.</p> |
