A kind of method for preparing ammonium sulfate from phosphogypsum and increasing the granularity of ammonium sulfate

Abstract

The invention discloses a method for preparing large particle ammonium sulfate from ardealite. The method comprises the steps of firstly adding water into ammonium sulfate generated by conversion of ardealite, ammonia gas and carbon dioxide according to certain proportion and mixing, after heating and dissolving through stirring, adding coal ash and white carbon black for purifying the ammonium sulfate solution, filtering the solution, standing the filtrate for a while, then evaporating and concentrating the filtrate, stopping heating when the density of the concentrated solution is 1.20-1.36g / cm<3>, transferring the concentrated solution to a 80-96 DEG C crystallizing tank, beginning stirring, after the temperature is constant, adding a crystallizing modifier, preserving heat for 20-40 minutes, then adding ammonium sulfate seed crystal, beginning programmed freezing when the seed crystal is not dissolved completely, stopping cooling when cooling to be 30-42 DEG C, filtering, and stoving so as to obtain large particle ammonium sulfate crystal product. The ammonium sulfate product prepared by the method has high purity, good chroma, and large particle, and is not easy to cake; in addition, the preparation method is simple in technological processes, low in production cost, and easy to realize industrialization.

Description

technical field

[0001] The invention relates to ammonium sulfate, in particular to a method for increasing the particle size and purity of the product ammonium sulfate in the process of preparing ammonium sulfate from phosphogypsum. Background technique

[0002] Ammonium sulfate is abbreviated as ammonium sulfate. It is a commonly used chemical fertilizer. Its solubility in water at 20°C is 75.4. It is acidic after being dissolved in water. It is easily absorbed by crops after being applied to the soil. It is especially suitable for alkaline soils. Ammonium sulfate can be used as In base fertilizer, topdressing fertilizer and compound fertilizer, when used as base fertilizer and topdressing fertilizer, cover soil and water after application, and use in compound fertilizer can improve the utilization rate of other elements in compound fertilizer and reduce fertilizer loss.

[0003] At present, the common ammonium sulfate in the market is mostly powdery or small granular ...

Examples

Embodiment 1

[0015] Take 400g of crystalline ammonium sulfate produced by a phosphate fertilizer factory, add 1000g of water, dissolve at a temperature of 70°C and a stirring speed of 200r / min, add 7g of fly ash and white carbon black, filter after 30min, and let the filtrate stand for 20min. Concentrate by heating until the density of the concentrated liquid is 1.20g / cm 3 , put the concentrated solution into a crystallization tank with a temperature of 80°C, stir at a speed of 300r / min, add 2.8g of crystal modifier magnesium sulfate, keep the temperature constant for 20min, add 18g of seed crystals, when the seeds are not completely dissolved, start Use program cooling, the cooling rate is 18°C / h, when it drops to 76°C, the cooling rate is reduced to 10°C / h, from the beginning of cooling and crystallization, the stirring speed is reduced by 20r / min per hour, when the temperature is lowered to 30°C, stop cooling and filter , drying, the purity of the obtained ammonium sulfate product is 99...

Embodiment 2

[0017] Take 650g of crystalline ammonium sulfate produced by a phosphate fertilizer factory, add 1000g of water, dissolve at a temperature of 50°C and a stirring speed of 600r / min, add 1.7g of white carbon black, filter after 40min, and then heat and concentrate the filtrate after standing for 30min. Concentrate density is 1.36g / cm 3 , Put the concentrated solution into a crystallization tank with a temperature of 96°C, stir at a speed of 400r / min, add 4g of zinc sulfate as a crystal modifier, keep the temperature constant for 30min, add 7g of seed crystals, and start using Programmed cooling, the cooling rate is 22°C / h. When it drops to 76°C, the cooling rate is reduced to 12°C / h. From the beginning of cooling and crystallization, the stirring speed is reduced by 20r / min per hour. When the temperature drops to 42°C, stop cooling and filter. Drying, the ammonium sulfate product purity that obtains is 99.32%, and ammonium sulfate particle size is 3-4mm.

Embodiment 3

[0019] Take 500g of crystalline ammonium sulfate produced by a phosphate fertilizer factory, add 1000g of water, dissolve at a temperature of 60°C and a stirring speed of 400r / min, add 5g of fly ash, filter after 60min, and heat the filtrate to concentrate after standing for 40min. The liquid density is 1.28g / cm 3 , Put the concentrated solution into a crystallization tank with a temperature of 88°C, stir at a speed of 350r / min, add 4g of crystal modifier urea and 1g of magnesium sulfate, keep the temperature constant for 40min, add 9g of seed crystals, when the seeds are not completely dissolved , start to use program cooling, the cooling rate is 20°C / h, when it drops to 76°C, the cooling rate is reduced to 10°C / h, from the beginning of cooling and crystallization, the stirring speed is reduced by 20r / min per hour, and the cooling is stopped when the temperature drops to 40°C , filtered, dried, the obtained ammonium sulfate product has a purity of 99.15%, and the particle siz...

technical field

[0001] The invention relates to ammonium sulfate, in particular to a method for increasing the particle size and purity of the product ammonium sulfate in the process of preparing ammonium sulfate from phosphogypsum. Background technique

[0002] Ammonium sulfate is abbreviated as ammonium sulfate. It is a commonly used chemical fertilizer. Its solubility in water at 20°C is 75.4. It is acidic after being dissolved in water. It is easily absorbed by crops after being applied to the soil. It is especially suitable for alkaline soils. Ammonium sulfate can be used as In base fertilizer, topdressing fertilizer and compound fertilizer, when used as base fertilizer and topdressing fertilizer, cover soil and water after application, and use in compound fertilizer can improve the utilization rate of other elements in compound fertilizer and reduce fertilizer loss.

[0003] At present, the common ammonium sulfate in the market is mostly powdery or small granular ...

Examples

Embodiment 1

[0015] Take 400g of crystalline ammonium sulfate produced by a phosphate fertilizer factory, add 1000g of water, dissolve at a temperature of 70°C and a stirring speed of 200r / min, add 7g of fly ash and white carbon black, filter after 30min, and let the filtrate stand for 20min. Concentrate by heating until the density of the concentrated liquid is 1.20g / cm 3 , put the concentrated solution into a crystallization tank with a temperature of 80°C, stir at a speed of 300r / min, add 2.8g of crystal modifier magnesium sulfate, keep the temperature constant for 20min, add 18g of seed crystals, when the seeds are not completely dissolved, start Use program cooling, the cooling rate is 18°C / h, when it drops to 76°C, the cooling rate is reduced to 10°C / h, from the beginning of cooling and crystallization, the stirring speed is reduced by 20r / min per hour, when the temperature is lowered to 30°C, stop cooling and filter , drying, the purity of the obtained ammonium sulfate product is 99...

Embodiment 2

[0017] Take 650g of crystalline ammonium sulfate produced by a phosphate fertilizer factory, add 1000g of water, dissolve at a temperature of 50°C and a stirring speed of 600r / min, add 1.7g of white carbon black, filter after 40min, and then heat and concentrate the filtrate after standing for 30min. Concentrate density is 1.36g / cm 3 , Put the concentrated solution into a crystallization tank with a temperature of 96°C, stir at a speed of 400r / min, add 4g of zinc sulfate as a crystal modifier, keep the temperature constant for 30min, add 7g of seed crystals, and start using Programmed cooling, the cooling rate is 22°C / h. When it drops to 76°C, the cooling rate is reduced to 12°C / h. From the beginning of cooling and crystallization, the stirring speed is reduced by 20r / min per hour. When the temperature drops to 42°C, stop cooling and filter. Drying, the ammonium sulfate product purity that obtains is 99.32%, and ammonium sulfate particle size is 3-4mm.

Embodiment 3

[0019] Take 500g of crystalline ammonium sulfate produced by a phosphate fertilizer factory, add 1000g of water, dissolve at a temperature of 60°C and a stirring speed of 400r / min, add 5g of fly ash, filter after 60min, and heat the filtrate to concentrate after standing for 40min. The liquid density is 1.28g / cm 3 , Put the concentrated solution into a crystallization tank with a temperature of 88°C, stir at a speed of 350r / min, add 4g of crystal modifier urea and 1g of magnesium sulfate, keep the temperature constant for 40min, add 9g of seed crystals, when the seeds are not completely dissolved , start to use program cooling, the cooling rate is 20°C / h, when it drops to 76°C, the cooling rate is reduced to 10°C / h, from the beginning of cooling and crystallization, the stirring speed is reduced by 20r / min per hour, and the cooling is stopped when the temperature drops to 40°C , filtered, dried, the obtained ammonium sulfate product has a purity of 99.15%, and the particle siz...