| 摘要 |
<p>Waste waters contg. decomposable organic impurities are removed, with simultaneous use of impurities in prodn of fertilisers. After opt. concn the waste waters are charged to standard prodn of fertilisers by condensn. of urea with HCHO in an acid aq. medium. Process is used esp. with waste waters from yeast factories; distilleries; fermentation processes, e.g. for prodn. of citric- oar lactic acid, ore prepn of antibiotics or enzymes, or from breweries, waste waters from pulping, dairies, slaughter-houses and processing de-saccharide molasses from sugar industry. A solid, light-brown to cream-coloured crumbly prod can be obtd. contg. >30 % N, N can be released slowly over a long period. Prod. is stable to storage, non-hygros copic and does not corrode packing material. In an example, wrot, from yeast mfr. was used. 50g urea were dissolved in 100g wort. Mixt. was set to 50 degrees C and pH 3.2, with 50%lactic acid. 60 ml 40% aq. HCHO soln were added. Slurry formed solidified to form a powder having a pleasant, aromatic odour.</p> |
