CN1463957A

CN1463957A - Granulation process of composite fertilizer

Info

Publication number: CN1463957A
Application number: CN 02113149
Authority: CN
Inventors: 邵建华
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-12
Filing date: 2002-06-12
Publication date: 2003-12-31

Abstract

The granulation method is that while molten urea with H2SO4 or H3OP4 is sprayed to disc granulating machine or roller granulating machine, phosphate fertilizer, potash fertilizer and stuffing are sprayed and steam is sprayed to complete granulation. The granulation method has high production efficiency of composite fertilizer, less loss of nutrients in production, high stoving speed, low power consumption of stoving and no environmental pollution cause by decomposition of urea.

Description

Granulation method of compound fertilizer

The invention belongs to the field of compound fertilizer manufacturing, and relates to a novel compound fertilizer granulation process.

The existing compound fertilizer plants use disc or roller granulation equipment, and water accounting for 6-10% of the total amount of the compound fertilizer is sprayed during granulation so as to facilitate granulation. Because water is added as a bonding medium during granulation, the granulation needs to be dried by using large heat energy, and the energy consumption is wasted. Many manufacturers also spray urea as bonding medium directly into a disc or roller granulator after melting the urea, but the urea is subjected to condensation reaction after melting to generate biuret and triurea, and the reaction is as follows: due to NH₃The generation of the ammonia gas causes the loss of a large amount of nitrogen nutrients, the nutrient loss reaches 2 to 3 percent, and meanwhile, the overflowed ammonia gas causes serious environmental pollution.

According to the invention, the urea is added with the nonvolatile acid, such as sulfuric acid and phosphoric acid, so that the decomposition of the urea is effectively inhibited, a small amount of generated ammonia gas also rapidly reacts with the sulfuric acid to generate ammonium sulfate, or reacts with the phosphoric acid to generate ammonium hydrogen phosphate, and the nutrient is basically not lost.

The present invention is thus achieved. Adding 100kg of urea into an iron tank, adding 20-60kg of metered concentrated sulfuric acid, heating and melting under stirring, pumping into a disc or a roller, and mixing with the prepared phosphate fertilizer and potash fertilizer for granulation. And (4) calculating the spraying amount of the urea molten slurry according to the proportion of the compound fertilizer, and then adjusting the spraying speed of the metering pump. In order to ensure that the spraying speed is uniform, steam can be used as power to uniformly atomize the sprayed molten urea slurry according to the jet flow principle. The urea pipeline is sleeved with the steam pipeline, so that the pipeline is prevented from being blocked after molten urea is cooled under the condition that steam is introduced. The material proportion of each ton of the ternary compound fertilizer is as follows:

urea: 100-400kg of ammonium chloride: 100-300kg

Concentrated sulfuric acid: 5-40kg of potassium chloride: 100-400kg

Ammonium dihydrogen phosphate: 200 and 350kg of filler: 100-400kg

Example 1: (45% ternary Compound fertilizer N₁₅-P₁₅-K₁₅)

Urea: 300kg of potassium chloride: 300kg of

Concentrated sulfuric acid: 15kg of stone powder: 85kg of

Ammonium dihydrogen phosphate: 300kg of

Adding 15kg of concentrated sulfuric acid into 300kg of urea, heating, melting, spraying, atomizing, mixing with 300kg of ammonium dihydrogen phosphate and 300kg of potassium chloride, mixing, blending, granulating,drying, cooling and sieving to obtain the ternary compound fertilizer with the nutrient content of 45%. Example 2: (nutrient 30% N)₁₀-P₁₀-K₁₀)

Urea: 200kg of concentrated sulfuric acid: 10kg of

Ammonium chloride: 50kg of heavy superphosphate: 250kg of

Potassium chloride: 200kg of kaolin: 275kg

Melting concentrated sulfuric acid 10kg in urea 200kg, atomizing by steam spraying, granulating with mixture of ammonium chloride 50kg, calcium superphosphate 250kg, potassium chloride 200kg and filler 275kg fed by a stirrer, drying, cooling and sieving to obtain the 30% nutrient ternary compound fertilizer.

Claims

1. A granulating process for preparing composite fertilizer includes such steps as proportionally adding sulfuric acid or phosphoric acid to urea, fusing, spraying it to disk or drum granulator, granulating, and spraying steam to obtain particles, which are then granulated together with phosphate fertilizer, potash fertilizer and filler.

2. The proportion of sulphuric acid or phosphoric acid according to claim 1, which is 4-10% of the total amount of urea or 1-5% of the total amount of the compound fertilizer.

3. The compound fertilizer as claimed in claim 1, which may be binary, ternary compound fertilizer and full-element compound fertilizer with medium trace elements.

4. The phosphate fertilizer according to claim 1 may be superphosphate, calcium magnesium phosphate, ammonium hydrogen phosphate, potassium hydrogen phosphate and other phosphate fertilizers.

5. The potash fertilizer according to claim 1, may be potassium sulfate, potassium chloride, and other potash fertilizers.