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Method for preparing urea ardealite by solution crystallization method taking ardealite as raw material

A technology of solution crystallization and phosphogypsum, which is applied in applications, fertilizer mixtures, fertilization devices, etc., can solve problems such as high moisture content, and achieve the effects of uniform particle size, precise and adjustable purity, and stable quality

Inactive Publication Date: 2013-05-08
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Although phosphogypsum has the same main component as calcium sulfate dihydrate with natural gypsum, it contains acidic substances and various impurities, and has a high water content and chromaticity.

Method used

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  • Method for preparing urea ardealite by solution crystallization method taking ardealite as raw material
  • Method for preparing urea ardealite by solution crystallization method taking ardealite as raw material
  • Method for preparing urea ardealite by solution crystallization method taking ardealite as raw material

Examples

Experimental program
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Effect test

Embodiment 1

[0044] according to figure 1 In the process flow shown, under the condition of 20°C, add urea and water into the slurry mixing tank to prepare a saturated urea solution. Add phosphogypsum with a mass molar ratio of 0.9:1.0:0.1 to the saturated urea solution (based on CaSO in phosphogypsum 4 .2H 2 O meter), urea (dosing urea), ammonium dihydrogen phosphate to form a slurry of phosphogypsum and urea. Pump the slurry into the crystallization reactor, continue to stir evenly, maintain the temperature at 20°C, and stay for 10.0 hours to complete the reaction of phosphogypsum, ammonium dihydrogen phosphate and urea and convert it into urea phosphogypsum slurry, and pump the urea phosphogypsum slurry to vacuum Belt filter for solid-liquid separation. The solid phase was sent to a fluidized bed dryer for drying at 60° C. for 5 minutes to obtain urea phosphogypsum with a purity of 53.2%. After packaging, it is a urea phosphogypsum product. The separated liquid phase is returned to...

Embodiment 2

[0047] according to figure 1 In the process flow shown, under the condition of 30°C, add urea and water into the slurry mixing tank to prepare a saturated urea solution. Phosphogypsum with a mass molar ratio of 0.8:2.0:0.2 was added to the saturated urea solution (based on CaSO in phosphogypsum 4 .2H 2 O meter), urea (the urea added), sodium dihydrogen phosphate to form a slurry of phosphogypsum and urea. Pump the slurry into the crystallization reactor, continue to stir evenly, maintain the temperature at 30°C, and stay for 8.0 hours to complete the reaction of phosphogypsum, sodium dihydrogen phosphate and urea and convert it into urea phosphogypsum slurry, and pump the urea phosphogypsum slurry to vacuum Belt filter for solid-liquid separation. The solid phase was sent to a fluidized bed dryer for drying at 65° C. for 4 minutes to obtain urea phosphogypsum with a purity of 68.2%, which was packaged as a urea phosphogypsum product. The separated liquid phase is returned ...

Embodiment 3

[0050] according to figure 1 In the process flow shown, under the condition of 40°C, add urea and water into the slurry mixing tank to prepare a saturated urea solution. Add phosphogypsum with a mass molar ratio of 0.7:3.0:0.3 to the saturated urea solution (based on CaSO in phosphogypsum 4 .2H 2 O meter), urea (dosing urea), potassium dihydrogen phosphate to form a slurry of phosphogypsum and urea. The slurry is pumped into the crystallization reactor, continuously stirred evenly, the temperature is maintained at 40°C, the residence time is 6.0h, the reaction of phosphogypsum, potassium dihydrogen phosphate and urea is completed and converted into urea phosphogypsum slurry, and the urea phosphogypsum slurry is pumped to the centrifuge Filter for solid-liquid separation. The solid phase is sent to a fluidized bed dryer for drying at 70° C. for 3 minutes to obtain urea phosphogypsum with a purity of 79.5%, which is packaged as a urea phosphogypsum product. The separated liq...

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Abstract

The invention discloses a method for preparing urea ardealite by a solution crystallization method taking ardealite as raw material. The method comprises the following steps of: (1) preparing a saturated urea aqueous solution, and adding ardealite, soluble phosphate and urea into the saturated urea aqueous solution to form slurry; (2) in the conditions of normal pressure and normal temperature, uniformly mixing the slurry and performing crystallization reaction to obtain urea ardealite slurry; and (3) performing solid-liquid separation on the urea ardealite slurry, and then drying the solid phase to obtain the urea ardealite. According to the invention, on the conditions of normal pressure and normal temperature, ardealite, soluble phosphate and urea are used as raw materials, a solution crystallization method is adopted, the investment is small, and the operation is convenient; and the prepared urea ardealite has the characteristics of regular crystal form, uniform granularity, accurate adjustment of purity and stable quality.

Description

technical field [0001] The invention belongs to the field of resource utilization of bulk solid waste phosphogypsum, and also belongs to the field of chemical fertilizer manufacturing, and specifically relates to a nitrogen, phosphorus, and sulfide fertilizer-urea phosphorus, which uses phosphogypsum, soluble phosphate, and urea as raw materials and uses a solution crystallization method to prepare plaster method. Background technique [0002] Agriculture is inseparable from chemical fertilizers. The amount of chemical fertilizers used in my country continues to increase. In 2010, the total amount reached 55.617 million tons, including 23.537 million tons of nitrogen fertilizers, 8.056 million tons of phosphate fertilizers, and 17.985 million tons of compound fertilizers. However, the utilization rate of nitrogen fertilizer in my country is low, and the utilization rate is only 30-50%. The lost N has caused serious environmental problems, such as: entering the water body an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05G1/00
Inventor 官宝红朱依刚
Owner ZHEJIANG UNIV
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