A method for wet phosphoric acid producing high pure calcium hydrogen orthophosphate

Abstract

The invention relates to a method for wet phosphoric acid producing high pure calcium hydrogen orthophosphate and monoammonium phosphate of fertiliser stage, which is indicated as wet phosphoric acid aminated, filtrating the ground paste after aminated, drying and packing the filter residue and obtaining monoammonium phosphate of fertiliser stage, obtaining high pure monoammonium phosphate crystalafter the filtrate evaporated, crystallized and refiltered, generating calcium hydrogen orthophosphate and ammine by taking monoammonium phosphate reacting with calcium hydrogen orthophosphate of technical grade or alimentary products stage, aminating phosphoric acid after ammine recovered, and drying the calcium hydrogen orthophosphate deposition, then the high pure calcium hydrogen orthophosphate products is produced. The method in this invention can use wet method phosphoric acid with high impurity content to produce high pure calcium hydrogen orthophosphate, which can be used as calcium phosphorus additive agent of feed stuff stage or alimentary products stage based on the raw charge.

Description

technical field

[0001] The invention relates to a method for producing high-purity calcium hydrogen phosphate by wet-process phosphoric acid purification, and simultaneously produces fertilizer-grade monoammonium phosphate. The calcium hydrogen phosphate produced by the method can be used as a feed-grade or food-grade calcium hydrogen phosphate additive. Background technique

[0002] At present, the main processes for producing high-purity calcium hydrogen phosphate and monoammonium phosphate at home and abroad are: At present, the methods for domestic production of feed grade calcium hydrogen phosphate mainly include thermal phosphoric acid method, wet process phosphoric acid two-stage neutralization method, superphosphate hot water immersion Method etc. The thermal phosphoric acid method has high energy consumption, heavy pollution, and high cost. The wet-process phosphoric acid two-stage neutralization method uses limestone powder in the second-stage precipitation, and th...

Examples

Embodiment 1

[0036] 26%P 2 o 5Wet-process phosphoric acid 2 is fed into the ammoniation tank 3 at a rate of 13.9t / h, and ammonia 4 is added at a rate of 0.87t / h at the same time. The ammoniation aging temperature is 100°C, the pH value of the ammoniation slurry is 4.0, and the reaction and aging time is 1 day. The aged ammoniated slurry 5 is deaminated by the slurry filter 6. After being filtered and separated by the rotary drum vacuum filter, the filter residue 7 enters the drying device 8, and the drum dryer is used, and the air temperature at the inlet of the dryer is controlled to be 200~ 250°C, the outlet air temperature is 100-120°C, after drying and packaging, fertilizer-grade monoammonium phosphate is obtained; the filtrate is evaporated and crystallized 12 to obtain monoammonium phosphate crystals, 40% of the monoammonium phosphate filtrate 15 (volume%, hereinafter the same ) returns to the ammoniation tank 3, and 60% goes to the drying device 8; the monoammonium phosphate cryst...

Embodiment 2

[0038] 15%P 2 o 5 Content Wet-process phosphoric acid 2 is fed into ammoniation tank 3 at a rate of 24.1t / h, and ammonia 4 is added at a rate of 0.95t / h at the same time. The ammoniation aging temperature is 60°C, the pH value of the ammoniation slurry is 6.8, and the reaction and aging time is 0.5 days. The aged ammoniated slurry 5 is deaminated by the slurry filter 6. After being filtered and separated by the rotary drum vacuum filter, the filter residue 7 enters the drying device 8, and the drum dryer is used, and the air temperature at the inlet of the dryer is controlled to be 200~ 250°C, the outlet air temperature is 100-120°C, after drying and packaging, fertilizer-grade monoammonium phosphate is obtained; the filtrate is evaporated and crystallized 12 to obtain monoammonium phosphate crystals, and 50% of the monoammonium phosphate filtrate 15 is returned to the ammoniation tank 3, 50% to the drying device 8; the monoammonium phosphate crystal enters the neutralizatio...

Embodiment 3

[0040] 46%P 2 o 5 Content Wet-process phosphoric acid 2 is fed into ammoniation tank 3 at a rate of 7.86t / h, and ammonia 4 is added at a rate of 0.85t / h at the same time. The ammoniation aging temperature is 110°C, the pH value of the ammoniation slurry is 3.8, and the reaction and aging time is 5 days. The aged ammoniated slurry 5 is deaminated by the slurry filter 6. After being filtered by a plate and frame filter press, the filter residue 7 enters the drying device 8. A drum dryer is used to control the air temperature at the inlet of the dryer to 200-250 ℃, the outlet air temperature is 100-120 ℃, after drying and packaging, fertilizer-grade monoammonium phosphate is obtained; the filtrate is evaporated and crystallized 12 to obtain monoammonium phosphate crystals, and 20% of the monoammonium phosphate filtrate 15 is returned to the ammoniation tank 3,80 % go to the drying device 8; the monoammonium phosphate crystal enters the neutralization tank 17 after being centrif...

technical field

[0001] The invention relates to a method for producing high-purity calcium hydrogen phosphate by wet-process phosphoric acid purification, and simultaneously produces fertilizer-grade monoammonium phosphate. The calcium hydrogen phosphate produced by the method can be used as a feed-grade or food-grade calcium hydrogen phosphate additive. Background technique

[0002] At present, the main processes for producing high-purity calcium hydrogen phosphate and monoammonium phosphate at home and abroad are: At present, the methods for domestic production of feed grade calcium hydrogen phosphate mainly include thermal phosphoric acid method, wet process phosphoric acid two-stage neutralization method, superphosphate hot water immersion Method etc. The thermal phosphoric acid method has high energy consumption, heavy pollution, and high cost. The wet-process phosphoric acid two-stage neutralization method uses limestone powder in the second-stage precipitation, and th...

Examples

Embodiment 1

[0036] 26%P 2 o 5Wet-process phosphoric acid 2 is fed into the ammoniation tank 3 at a rate of 13.9t / h, and ammonia 4 is added at a rate of 0.87t / h at the same time. The ammoniation aging temperature is 100°C, the pH value of the ammoniation slurry is 4.0, and the reaction and aging time is 1 day. The aged ammoniated slurry 5 is deaminated by the slurry filter 6. After being filtered and separated by the rotary drum vacuum filter, the filter residue 7 enters the drying device 8, and the drum dryer is used, and the air temperature at the inlet of the dryer is controlled to be 200~ 250°C, the outlet air temperature is 100-120°C, after drying and packaging, fertilizer-grade monoammonium phosphate is obtained; the filtrate is evaporated and crystallized 12 to obtain monoammonium phosphate crystals, 40% of the monoammonium phosphate filtrate 15 (volume%, hereinafter the same ) returns to the ammoniation tank 3, and 60% goes to the drying device 8; the monoammonium phosphate cryst...

Embodiment 2

[0038] 15%P 2 o 5 Content Wet-process phosphoric acid 2 is fed into ammoniation tank 3 at a rate of 24.1t / h, and ammonia 4 is added at a rate of 0.95t / h at the same time. The ammoniation aging temperature is 60°C, the pH value of the ammoniation slurry is 6.8, and the reaction and aging time is 0.5 days. The aged ammoniated slurry 5 is deaminated by the slurry filter 6. After being filtered and separated by the rotary drum vacuum filter, the filter residue 7 enters the drying device 8, and the drum dryer is used, and the air temperature at the inlet of the dryer is controlled to be 200~ 250°C, the outlet air temperature is 100-120°C, after drying and packaging, fertilizer-grade monoammonium phosphate is obtained; the filtrate is evaporated and crystallized 12 to obtain monoammonium phosphate crystals, and 50% of the monoammonium phosphate filtrate 15 is returned to the ammoniation tank 3, 50% to the drying device 8; the monoammonium phosphate crystal enters the neutralizatio...

Embodiment 3

[0040] 46%P 2 o 5 Content Wet-process phosphoric acid 2 is fed into ammoniation tank 3 at a rate of 7.86t / h, and ammonia 4 is added at a rate of 0.85t / h at the same time. The ammoniation aging temperature is 110°C, the pH value of the ammoniation slurry is 3.8, and the reaction and aging time is 5 days. The aged ammoniated slurry 5 is deaminated by the slurry filter 6. After being filtered by a plate and frame filter press, the filter residue 7 enters the drying device 8. A drum dryer is used to control the air temperature at the inlet of the dryer to 200-250 ℃, the outlet air temperature is 100-120 ℃, after drying and packaging, fertilizer-grade monoammonium phosphate is obtained; the filtrate is evaporated and crystallized 12 to obtain monoammonium phosphate crystals, and 20% of the monoammonium phosphate filtrate 15 is returned to the ammoniation tank 3,80 % go to the drying device 8; the monoammonium phosphate crystal enters the neutralization tank 17 after being centrif...

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