| 摘要 |
<p>1275521 Suspension fertilizers KNAPSACK AG 18 Feb 1970 [21 Feb 1969] 7796/70 Heading C1B A stabilized NPK, NP or PK suspension fertilizer has an overall nutrient concentration of at least 20 grams, preferably more than 30 grams, per 100 grams suspension fertiliser therein and contains a neutralization sludge stabilizer obtained in the neutralization of crude phosphoric acid produced by wet-processing treatment of phosphate ores with the use of an alkali liquor and/or ammonia. The neutralization sludge consists of water, sodium phosphate, potassium phosphate, ammonium phosphate, aluminium phosphate, iron phosphate, titanium phosphate, calcium phosphate, magnesium phosphate, according to the origin of the phosphate ore and customary contaminants such as fluoride, sulphate, organic substances, chromium, vanadium, manganese. A process for the manufacture of the above suspension fertilizers comprises mixing the neutralization sludge at 50-90‹ C. with agitation with a mineral acid, preferably phosphoric acid, and introducing the resulting mixture together with fertilizer salts and ammonia into a residual portion of a previously prepared fertilizer suspension at a rate such that the pH-value of the suspension is maintained between 5 and 9.</p> |
