CN1834070A - Spray pelleting process of compound fertilizer - Google Patents

Abstract

This invention relates to a method for spray granulation of composite fertilizers, that is, potassium chloride and oil of vitriol react with each other to produce potassium hydrosulphate solution. The potassium hydrosulphate solution is homogeneously mixed with ammonium dihydrophosphate and reacts with ammonia to produce neutralization paste containing ammonium sulphate, potassium sulphate and diammonium hydrophosphate. The neutralization paste is then granulated, dried, cooled and screened to obtain composite fertilizers. This spray granulation of composite fertilizers has the advantages of low production cost and smooth particle surfaces.

Description

A kind of spray pelleting process of composite fertilizer

Technical field

The present invention relates to a kind of preparation method of composite fertilizer, the spray pelleting process of a kind of composite fertilizer that more specifically says so.

Background technology

The prilling process of general composite fertilizer has agglomeration granulation method, extruder grain method and ammoniation-granulation method.The agglomeration granulation method is to contain the base fertilizer of n p k nutrition composition, as monoammonium phosphate, vitriolate of tartar, urea, ammonium sulfate or ammonium chloride etc., after stirring, to be agglomerated into particle with the cylinder tablets press; The extruder grain method is that above-mentioned raw material is squeezed into particle with Squeezinggranulator.The weak point of above-mentioned two kinds of methods is vitriolate of tartar, urea, ammonium sulfate or the ammonium oxide in the used raw material, all is the base fertilizer that is prepared into finished product, produces compound manure with these base fertilizers regeneration, thereby has caused the production cost height.The weak point of ammoniation-granulation method is: 1, after finishing granulation, enter drying machine drying again, and many baking steps, thus caused the production cost height; 2, particle surface is not slick and sly, and traction is low.

Summary of the invention

The spray pelleting process that the purpose of this invention is to provide the composite fertilizer that a kind of production cost is low, particle surface is slick and sly.

In order to realize above-mentioned purpose, the spray pelleting process of the composite fertilizer that is provided comprises the steps: successively

A, dechlorination are reaction 45 minutes-60 minutes under 100 ℃-130 ℃ the condition by weight in temperature with the Repone K of 110 parts of-130 parts of vitriol oils and 75 parts-85 parts, generate potassium hydrogen sulfate solution and hydrogenchloride;

B, neutralization, by weight with 50 parts of-100 parts of potassium hydrogen sulfate solutions and 90 parts of monoammonium phosphate aqueous solution uniform mixing that-130 parts of concentration are 60%-70% (wt), feed liquefied ammonia then, sal enixum and ammonia react generate vitriolate of tartar and ammonium sulfate, sulfuric acid and ammonia react generate ammonium sulfate, ammonium phosphate and ammonia react generation diammonium phosphate, the degree of neutralization that back solution is finished in reaction is controlled at 1.1-1.2, in the vitriolate of tartar that is generated in the reaction solution, ammonium sulfate and the diammonium phosphate formation and slurry;

C, granulation, with in and slurry pressure be that the pressurized air of 0.3Mpa-0.4Mpa atomizes through spray gun ejection, in being atomized and slurry be sprayed onto on the outside surface of the returning charge of kicking up in the tablets press, form particle with returning charge, these particles and temperature are that 380 ℃-450 ℃ hot blast directly contacts, and setting is dried;

D, oven dry, the particle temperature of the setting that is dried is 100 ℃-200 ℃ a hot-air seasoning, makes particulate water content≤2% of being dried;

E, cooling are cooled to room temperature with the particle blowing of drying, and prevent the particle caking;

F, screening, with cooled particle is respectively the sieve of 1.5mm and 4.75mm with the aperture, filter out granularity less than the small-particle of 1.5mm and powder and granularity greater than the macrobead of 4.75mm as returning charge, send into the granulation again of C step, remaining particle is finished product.

In the above-mentioned C step, during the consumption of returning charge is atomized by weight and 2 times-4 times of slurry.

The spray pelleting process of composite fertilizer provided by the present invention in the dechlorination operation, be controlled the usage ratio of sulfuric acid and Repone K, the sulfuric acid consumption is excessive, can cause the waste of raw material, and potassium chloride dosage is too much, then can not complete reaction, the chlorion in the product is exceeded standard, cause product defective.In and operation, the potassium hydrogen sulfate solution and the monoammonium phosphate aqueous solution are wanted uniform mixing, otherwise will cause the nutrient skewness in the product, make the nutrient of product defective.

The spray pelleting process of composite fertilizer provided by the present invention, its beneficial effect is: 1, because sulfuric acid, Repone K, liquefied ammonia in raw materials used are industrial chemicals, monoammonium phosphate is the rough-wrought product of Rock Phosphate (72Min BPL), therefore production cost is low, and the cost of composite fertilizer per ton is than reducing 20%-25% with agglomeration granulation method, extruder grain method or ammoniation-granulation method; 2, particle surface slyness, the traction height.

Embodiment

Example 1

With 23 tons of concentration is that sulfuric acid and 15 tons of Repone K of 98% join in the reactor; be heated to 100 ℃; reacted 60 minutes; generate 30 tons of potassium hydrogen sulfate solutions; add 18.5 tons of water with 34 tons of monoammonium phosphates; be heated to 100 ℃; generate 52.5 tons of monoammonium phosphate aqueous solution; 5 tons of urea are joined in the mixed solution of the potassium hydrogen sulfate solution that makes and the monoammonium phosphate aqueous solution and dissolve; and stir; form 87.5 tons nitration mixture; carry out neutralization reaction with 12.3 tons liquefied ammonia and nitration mixture; in the formation and slurry; with squeezing into second-rate external mix spray gun with slurry among the submerged pump general; the pressurized air of being sent here by the air station also enters spray gun; ejection atomized with slurry during pressurized air was incited somebody to action; be sprayed onto on the outside surface of the returning charge of kicking up in the tablets press with slurry in being atomized; form particle with returning charge; these particles and temperature are that 380 ℃-450 ℃ hot blast directly contacts; setting is dried; be 100 ℃-200 ℃ hot-air seasoning again with temperature; behind the blowing cool to room temperature; sieve out the particle that granularity is 1.5mm-4.75mm; make nitrogenous by weight 15%; phosphorus 15%; the composite fertilizer of potassium 15%; the granularity of sieving out less than the small-particle of 1.5mm and powder and granularity greater than the macrobead of 4.75mm as returning charge, send into tablets press granulation again.

Example 2

With 23 tons of concentration is that sulfuric acid and 15 tons of Repone K of 98% join in the reactor; be heated to 100 ℃; reacted 60 minutes; generate 30 tons of potassium hydrogen sulfate solutions; add 19.6 tons of water with 36.4 tons of monoammonium phosphates; be heated to 100 ℃; generate 56 tons of monoammonium phosphate aqueous solution; the potassium hydrogen sulfate solution and the monoammonium phosphate aqueous solution that make are stirred; form 86 tons nitration mixture; carry out neutralization reaction with 14 tons liquefied ammonia and nitration mixture; in the formation and slurry; with squeezing into second-rate external mix spray gun with slurry among the submerged pump general; the pressurized air of being sent here by the air station also enters spray gun; ejection atomized with slurry during pressurized air was incited somebody to action; be sprayed onto on the outside surface of the returning charge of kicking up in the tablets press with slurry in being atomized; form particle with returning charge; these particles and temperature are that 380 ℃-450 ℃ hot blast directly contacts; setting is dried; be 100 ℃-200 ℃ hot-air seasoning again with temperature; behind the blowing cool to room temperature, sieve out the particle that granularity is 1.5mm-4.75mm, make nitrogenous by weight 14%; phosphorus 16%; the composite fertilizer of potassium 15%; the granularity of sieving out less than the small-particle of 1.5mm and powder and granularity greater than the macrobead of 4.75mm as returning charge, send into tablets press granulation again.

Example 3

With 30.3 tons of concentration is that sulfuric acid and 20.2 tons of Repone K of 98% join in the reactor; be heated to 100 ℃; reacted 60 minutes; generate 40 tons of potassium hydrogen sulfate solutions; add 18.5 tons of water with 34 tons of monoammonium phosphates; be heated to 100 ℃; generate 52.5 tons of monoammonium phosphate aqueous solution; the potassium hydrogen sulfate solution and the monoammonium phosphate aqueous solution that make are stirred; form 92.5 tons nitration mixture; carry out neutralization reaction with 8.7 tons liquefied ammonia and nitration mixture; in the formation and slurry; with squeezing into second-rate external mix spray gun with slurry among the submerged pump general; the pressurized air of being sent here by the air station also enters spray gun; ejection atomized with slurry during pressurized air was incited somebody to action; be sprayed onto on the outside surface of the returning charge of kicking up in the tablets press with slurry in being atomized; form particle with returning charge; these particles and temperature are that 380 ℃-450 ℃ hot blast directly contacts; setting is dried; be 100 ℃-200 ℃ hot-air seasoning again with temperature; behind the blowing cool to room temperature; sieve out the particle that granularity is 1.5mm-4.75mm; make nitrogenous by weight 10%; phosphorus 15%; the composite fertilizer of potassium 20%; the granularity of sieving out less than the small-particle of 1.5mm and powder and granularity greater than the macrobead of 4.75mm as returning charge, send into tablets press granulation again.

Claims (2)

1, a kind of spray pelleting process of composite fertilizer is characterized in that comprising the steps: successively

A, dechlorination are reaction 45 minutes-60 minutes under 100 ℃-130 ℃ the condition by weight in temperature with the Repone K of 110 parts of-130 parts of vitriol oils and 75 parts-85 parts, generate potassium hydrogen sulfate solution and hydrogenchloride;

B, neutralization, by weight with 50 parts of-100 parts of potassium hydrogen sulfate solutions and 90 parts of monoammonium phosphate aqueous solution uniform mixing that-130 parts of concentration are 60%-70% (wt), feed liquefied ammonia then, sal enixum and ammonia react generate vitriolate of tartar and ammonium sulfate, sulfuric acid and ammonia react generate ammonium sulfate, monoammonium phosphate and ammonia react generation diammonium phosphate, the degree of neutralization that back solution is finished in reaction is controlled at 1.1-1.2, in the vitriolate of tartar that is generated in the reaction solution, ammonium sulfate and the diammonium phosphate formation and slurry;

C, granulation, with in and slurry pressure be that the pressurized air of 0.3Mpa-0.4Mpa atomizes through spray gun ejection, in being atomized and slurry be sprayed onto on the outside surface of the returning charge of kicking up in the tablets press, form particle with returning charge, these particles and temperature are that 380 ℃-450 ℃ hot blast directly contacts, and setting is dried;

D, oven dry, the particle temperature of the setting that is dried is 100 ℃-200 ℃ a hot-air seasoning, makes particulate water content≤10% of being dried;

E, cooling are cooled to room temperature with the particle blowing of drying, and prevent the particle caking;

F, screening, with cooled particle is respectively the sieve of 1.5mm and 4.75mm with the aperture, filter out granularity less than the small-particle of 1.5mm and powder and granularity greater than the macrobead of 4.75mm as returning charge, send into the granulation again of C step, remaining particle is finished product.

2, the spray pelleting process of composite fertilizer according to claim 1 is characterized in that in the C step, during the consumption of returning charge is atomized by weight and 2 times-4 times of slurry.