Fertiliser contg. nitrogen, phosphorus, potassium and calcium nitrate - prepd. from cane sugar molasses or vinasse by neutralising, converting insoluble calcium cpds. to solubles and burning

摘要

A fertiliser, obtd. from molasses or vinasse from cane sugar contains 0.5-6% N, 0.1-1.5% P, 5-20% K and 0.15-13.5% Ca(NO3)2. The fertiliser does not have the disadvantages of previous fertilisers from molasses or vinasse which were strongly acid and therefore destroyed cane sugar plantations: in a few years and had to be kept in acid-resistant steel tanks. The gypsum which can cause encrustation in tanks and pipes holding the fertiliser is removed or converted to a water soluble Ca cpd. The molasses or vinasse is neutralised to pH 5-8 (pref. 6.8) pref. using lime. Any insoluble Ca present as gypsum is converted to soluble Ca using e.g. NH4NO3 or Na2S2O3. The resulting mass is concd. to 50-90 (pref. 68%) dry materials and then burnt to give the fertiliser.