A method of obtaining a granulated phosphorus-potassium fertilizers

 

(57) Abstract:

The invention relates to a method for producing granulated complex phosphorus-potassium fertilizers to increase the strength of granules, increase output fractions by granulation and reduce energy costs. Complex phosphorus-potassium fertilizers are produced by granulating a balling mixture of powdery double or simple superphosphate potassium chloride in the presence of moisture followed by drying the obtained granules, and potassium chloride is used with a particle size of less than 0.2 mm, 50 to 95 wt.%. The use of potassium chloride this size ensures uniformity of mixing with powder superphosphate. Granulated phosphorus-potassium fertilizers is carried out at a temperature in the granulator 20 - 60C humidity 10 to 19 wt.%. 1 C.p. f-crystals, 2 tab.

The invention relates to a method for producing a complex phosphorus-potassium (RK) - fertilizers, which are widely used in agriculture.

A method of obtaining RK-fertilizers by pressing mixture consisting of a powder of superphosphate and potassium chloride, followed by crushing and classification pressed product [1].

Closest to the proposed invention the technical essence is the method by which the powdery simple or double superphosphate is granulated in a drum granulator together with potassium chloride in the presence of water, followed by drying and classifying the obtained granules [2].

The disadvantages of this method are:

the relatively low yield of a given size and low strength pellets obtained fertilizers;

- the need to maintain relatively high humidity of the mixture in the granulator (20%), which increases the energy consumption for drying of the product, increasing the number of gas emissions into the atmosphere, and reduces the power output.

The aim of the invention is to increase the strength of granules, increasing the yield of the target fractions for granulation while reducing energy costs.

The objective is achieved by the fact that as a potassium component used dust fraction alpinevalley potassium chloride) may be obtained in the classification of fine-grained potassium chloride after drying. The use of potassium chloride this size ensures uniformity of mixing with powder superphosphate, the best plasticization of the granulated mixture, the homogeneity of the obtained granules and, as a consequence, increase the uniformity of the composition of the product and the durability of the pellets. At the same time create conditions to reduce the moisture content of the granulated mixture and reduce energy costs for the removal of moisture. Balling, charge lead with humidity 10 to 19 wt.% and the temperature of the charge 20-60aboutC.

The influence of particle size distribution of potassium chloride on the distribution of granules emerging from the laboratory granulator, the size and strength dried to 2% moisture pellets under the same conditions granulation can be seen from the table. 1 (phosphate component - powder double superphosphate; the composition of the product - P2ABOUT5= 27,13%, K2About = 26,91%).

The possibility of reducing the moisture content of the granulated mixture when using powdered potassium chloride is illustrated in the data table. 2.

To avoid the negative impact on the process of granulometry organic substances contained in potassium chloride (flotation reagents, anti-caking agent, and so on), the feasible, the solid fuel which can be free phosphoric acid, contained in the powder chamber of the superphosphates. The content of free acidity in the product coming out of the pellet mill should not exceed 4% (in terms of N3RHO4in order to avoid allocation of hydrogen chloride.

P R I m e R 1. 100 g powder double superphosphate, containing, % : R2ABOUT5SPM. = 48; P2ABOUT5free.=11; N2About=9, mixed with 12 g of limestone to neutralize the free acidity of superphosphate to a residual value 3% and then mixed with 83 g of potassium chloride (58% OFF2A) the grain size is 0.2 mm, the Mixture is granulated with balling at a temperature of 50aboutC and humidity of 18% . The obtained granules are dried at a temperature of 90aboutC. the Finished product contains 25,9% R2ABOUT5SPM.; 26,0% OFF2ABOUT; 2% N2O.

P R I m m e R 2. 100 g powder double superphosphate, containing, % : R2ABOUT5SPM. =48; P2ABOUT5free.=11; N2About=9, mixed with 83 g of potassium chloride (58% OFF2A) the grain size is 0.2 mm, the Mixture is fed into a drum granulator, which also served 13 g of limestone to neutralize the free acidity to a residual value of 2% . The mixture is granulated with balling at a temperature of 60aboutAnd in the>The5SPM.; 26,0% OFF2ABOUT; 2% N2O.

P R I m e R 3. 100 g of superphosphate, containing, %: R2ABOUT5SPM.= 19; P2ABOUT5free. = 7; N2On=12, is mixed with 6 g of limestone to neutralize the free acidity to a residual value 3% and then mixed with 33 g of potassium chloride (58% OFF2A) the grain size is 0.2 mm, the Mixture is granulated with balling at a temperature of 50aboutC and a humidity of 15%. The obtained granules are dried at a temperature of 90aboutC. the Finished product contains 14,7% R2ABOUT5SPM.; 14,8% TO2ABOUT; 2% N2O.

1. A method of OBTAINING a GRANULATED PHOSPHORUS-POTASSIUM FERTILIZERS with balling mixture powder double or simple superphosphate potassium chloride in the presence of moisture followed by drying the obtained granules, characterized in that, to improve the durability of the pellets and reduce energy costs, as the use of potassium chloride dust fraction when the content of particles less than 0.2 mm, 50 to 95 wt.%, and the washing is carried out at a humidity of 10 to 19 wt.%.

2. The method according to p. 1, characterized in that the temperature of the mixture in the granulator is 20 - 60oC.

 

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