A kind of method of producing potassium dihydrogen phosphate

Abstract

The invention relates to a monopotassium phosphate production method. Feed-grade calcium hydrogen phosphate and industrial-grade phosphoric acid are firstly subjected to a pre-decomposition reaction, potassium hydrogen sulfate is added for a double-decomposition reaction, calcium sulfate and filtrate are filtered out, the filtrate is purified, concentrated, cooled and crystallized, a monopotassium phosphate product is prepared, crystallization mother liquor returns to feed-grade calcium hydrogen phosphate for cyclic operation or is used in production of chloride-free compound fertilizer. Compared with the prior art, the recovery rate of phosphorus in feed-grade calcium hydrogen phosphate is substantially increased to 95% or above through pre-reaction of phosphoric acid and feed-grade calcium hydrogen phosphate, besides, the yield of potassium in potassium hydrogen phosphate reaches 99.5%, meanwhile, phosphoric acid is recycled, emission of waste liquor is avoided, the technological process is simple, the yield of phosphorous and potassium in raw materials is high, the production cost can be substantially reduced, and the method is environment-friendly and sustainable and has great competitive advantages.

Description

technical field

[0001] The present invention relates to the preparation of phosphate, especially relate to a kind of method of producing potassium dihydrogen phosphate. Background technique

[0002] Potassium dihydrogen phosphate is a colorless or white glossy rhomboid, soluble in water, its aqueous solution is acidic, slightly soluble in alcohol, and has hygroscopicity and deliquescence.

[0003] Potassium dihydrogen phosphate is widely used in industry, agriculture, food industry, and medicine: in agriculture, as a high-grade phosphorus and potassium compound fertilizer with high concentration, it has the effects of significantly increasing production, drought resistance, and cold resistance, and it is effective in preventing and controlling crop diseases and insect pests. It also has a special effect. In addition, because of its high nutritional content (P, K active ingredients >90%), stable chemical properties, odorless, tasteless, non-toxic, soluble in water, and non...

Examples

Embodiment 1

[0059] Mix 315kg of feed grade calcium hydrogen phosphate and 787.5kg of water in the reactor evenly, add 174.43kg of phosphoric acid solution with a mass percentage of 20%, the reaction temperature is 50°C, and add 727.07kg of 30% by mass of sulfuric acid after reacting for 1h Potassium hydrogen solution, the reaction temperature is 50°C, and the reaction time is 2h; after the reaction is completed, filter to obtain calcium sulfate and potassium dihydrogen phosphate-containing filtrate, and the loss rates of phosphorus and potassium in calcium sulfate are 4.93% and 0.26% respectively; After the filtrate was purified, it was filtered to remove impurities, and the resulting filtrate was concentrated and crystallized. During the crystallization process, the stirring speed was 80rpm / min, and the crystallization temperature was 20°C. After stirring and crystallizing for 3 hours, 136.01kg of potassium dihydrogen phosphate product and 494.81kg of mother liquor were obtained by filtrat...

Embodiment 2

[0061] Mix 230kg of feed grade calcium hydrogen phosphate and 1150kg of water in the reactor evenly, add 95.52kg of phosphoric acid solution with a mass percentage of 40%, the reaction temperature is 70°C, and add 389.31kg of 50% by mass of sulfuric acid after 2 hours of reaction Potassium hydrogen solution, the reaction temperature is 70°C, and the reaction time is 4h; filter after the reaction to obtain calcium sulfate and filtrate, the loss rates of phosphorus and potassium in calcium sulfate are 4.89% and 0.34% respectively; after the filtrate is purified, filter to remove Impurities, the obtained filtrate is concentrated and crystallized, the stirring speed of the crystallization process is 100rpm / min, and the crystallization temperature is 40°C. After stirring and crystallizing for 6h, filter to obtain 32.90kg of potassium dihydrogen phosphate product and 545.44kg of mother liquor, and the mother liquor is returned to the reactor. Circulation operation is carried out; the...

Embodiment 3

[0063] Mix 180kg of feed grade calcium hydrogen phosphate and 647.50kg of water in the reactor, add 426.87kg of mother liquor, and the reaction temperature is 70°C. After 1 hour of reaction, add 304.68kg of potassium hydrogensulfate solution with a mass percentage of 50%. The temperature is 70°C, and the reaction time is 4h; after the reaction is finished, filter to obtain calcium sulfate and filtrate, and the loss rates of phosphorus and potassium in calcium sulfate are 4.91% and 0.42% respectively; after the filtrate is purified, filter to remove impurities, and the obtained filtrate is processed Concentrated crystallization, the stirring speed of the crystallization process is 100rpm / min, and the crystallization temperature is 40°C. After stirring and crystallizing for 6 hours, 114.01kg of potassium dihydrogen phosphate product and 477.91kg of mother liquor are obtained by filtration, and the mother liquor is returned to the reactor for recycling operation; the product The c...

technical field

[0001] The present invention relates to the preparation of phosphate, especially relate to a kind of method of producing potassium dihydrogen phosphate. Background technique

[0002] Potassium dihydrogen phosphate is a colorless or white glossy rhomboid, soluble in water, its aqueous solution is acidic, slightly soluble in alcohol, and has hygroscopicity and deliquescence.

[0003] Potassium dihydrogen phosphate is widely used in industry, agriculture, food industry, and medicine: in agriculture, as a high-grade phosphorus and potassium compound fertilizer with high concentration, it has the effects of significantly increasing production, drought resistance, and cold resistance, and it is effective in preventing and controlling crop diseases and insect pests. It also has a special effect. In addition, because of its high nutritional content (P, K active ingredients >90%), stable chemical properties, odorless, tasteless, non-toxic, soluble in water, and non...

Examples

Embodiment 1

[0059] Mix 315kg of feed grade calcium hydrogen phosphate and 787.5kg of water in the reactor evenly, add 174.43kg of phosphoric acid solution with a mass percentage of 20%, the reaction temperature is 50°C, and add 727.07kg of 30% by mass of sulfuric acid after reacting for 1h Potassium hydrogen solution, the reaction temperature is 50°C, and the reaction time is 2h; after the reaction is completed, filter to obtain calcium sulfate and potassium dihydrogen phosphate-containing filtrate, and the loss rates of phosphorus and potassium in calcium sulfate are 4.93% and 0.26% respectively; After the filtrate was purified, it was filtered to remove impurities, and the resulting filtrate was concentrated and crystallized. During the crystallization process, the stirring speed was 80rpm / min, and the crystallization temperature was 20°C. After stirring and crystallizing for 3 hours, 136.01kg of potassium dihydrogen phosphate product and 494.81kg of mother liquor were obtained by filtrat...

Embodiment 2

[0061] Mix 230kg of feed grade calcium hydrogen phosphate and 1150kg of water in the reactor evenly, add 95.52kg of phosphoric acid solution with a mass percentage of 40%, the reaction temperature is 70°C, and add 389.31kg of 50% by mass of sulfuric acid after 2 hours of reaction Potassium hydrogen solution, the reaction temperature is 70°C, and the reaction time is 4h; filter after the reaction to obtain calcium sulfate and filtrate, the loss rates of phosphorus and potassium in calcium sulfate are 4.89% and 0.34% respectively; after the filtrate is purified, filter to remove Impurities, the obtained filtrate is concentrated and crystallized, the stirring speed of the crystallization process is 100rpm / min, and the crystallization temperature is 40°C. After stirring and crystallizing for 6h, filter to obtain 32.90kg of potassium dihydrogen phosphate product and 545.44kg of mother liquor, and the mother liquor is returned to the reactor. Circulation operation is carried out; the...

Embodiment 3

[0063] Mix 180kg of feed grade calcium hydrogen phosphate and 647.50kg of water in the reactor, add 426.87kg of mother liquor, and the reaction temperature is 70°C. After 1 hour of reaction, add 304.68kg of potassium hydrogensulfate solution with a mass percentage of 50%. The temperature is 70°C, and the reaction time is 4h; after the reaction is finished, filter to obtain calcium sulfate and filtrate, and the loss rates of phosphorus and potassium in calcium sulfate are 4.91% and 0.42% respectively; after the filtrate is purified, filter to remove impurities, and the obtained filtrate is processed Concentrated crystallization, the stirring speed of the crystallization process is 100rpm / min, and the crystallization temperature is 40°C. After stirring and crystallizing for 6 hours, 114.01kg of potassium dihydrogen phosphate product and 477.91kg of mother liquor are obtained by filtration, and the mother liquor is returned to the reactor for recycling operation; the product The c...

Images