METHOD FOR PREPARING LIME-AMMONIUM SALTPETER Russian patent published in 2004 - IPC

FIELD: chemical technology. SUBSTANCE: invention relates to manufacture of nitrogen fertilizer lime-ammonium saltpeter that, in contrast to ammonium nitrate, is explosion-proof and doesn't acidify the soil. Method involves mixing ammonium nitrate melt with calcium carbonate and process is carried out in the presence of magnesium nitrate taken in the amount 0.1-0.4% as measured for magnesium to product mass inhibiting formation of calcium nitrate in fertilizer and providing hygroscopicity and caking a fertilizer. Prepared fertilizer contains 0.2% of calcium nitrate, not above, and exhibits good consumers' properties due to high strength of granules. Method involves using chemically precipitated calcium carbonate with temperature 40 C, not below, and with particles size 0.1 mm, not above, and humidity 1%, not above that is prepared in the process of treatment of calcium nitrate tetrahydrate with ammonium carbonate isolating in nitric acid processing the natural calcium phosphate to complex fertilizer. Ammonium nitrate melt is prepared by evaporation of 40-60% aqueous solution formed in above indicated process or 87-92% ammonium nitrate solution as neutralization product of 56-59% nitric acid with ammonia. Magnesium nitrate can be prepared by effect of nitric acid on magnesite, magnesium oxide or hydroxide. Content of calcium nitrate in the end product is 0.1-0.2% and granules strength is 2 kg per a granule. EFFECT: improved preparing method. 8 cl, 1 ex