Vacuum crystallization technique for producing potassium nitrate from potassium chloride by sodium nitrate

A vacuum crystallization and production process technology, which is applied in the preparation of alkali metal nitrates, etc., can solve the problems of large circulating water volume and high energy consumption, and achieve the effects of short production process, simple operation, and mild conversion and separation conditions

Inactive Publication Date: 2008-03-19
CHANGSHA DESIGN & RES INST OF CHEM IND MIN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The object of the present invention is to overcome defects such as high conversion temperature in the production process of producing potassium nitrate by converting potassium chloride from sodium nitrate, large circulating water volume and high energy consumption in the solution cooling and crystallization process, and provide a solution cooling and crystallization process, Vacuum crystallization process for producing potassium nitrate by converting sodium nitrate into potassium chloride with less circulating water and lower energy consumption

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) The three raw materials of sodium chloride, potassium chloride and sodium nitrate are successively added to the stirring tank according to the proportion calculated by the corresponding phase diagram, and water is added to prepare the mother liquor of potassium nitrate at low temperature (30°C) for the first time. The low-temperature mother liquor is pumped into the batching reactor after being metered by the head tank, and then the mother liquor is indirectly heated and kept at 80°C;

[0024] (2) Through the adjustable screw feeder according to K:NO 3 -= Add sodium nitrate and potassium chloride at a molar ratio of 1:1.05, convert at a constant temperature of 80°C for 30 minutes, then pump the converted slurry into the heat preservation settling tank for settlement;

[0025] (3) After the slurry in the thermal insulation settling tank settles to a solid content of about 35% at 80°C, it is pumped into the thermal insulation filter centrifuge, and at the same tempera...

Embodiment 2

[0032] The temperature of the low temperature mother liquor prepared for the first time is 25 ℃; 3 -=1:1.1; the reaction temperature of sodium nitrate and potassium chloride is 75°C, and the time is 40 minutes; Potassium content in the salt is reduced to 1.43%, and potassium nitrate vacuum crystallization cold analysis temperature is 25 ℃; Others are the same as embodiment 1.

[0033] Compared with the traditional process, this embodiment can save about 18% of water and about 17% of energy. The content of potassium nitrate in the product meets the requirements of the national standard (GB / T1918-1998), the total yield of potassium ions is 96.11%, and the total yield of nitrate ions is 98.42%.

Embodiment 3

[0035] The temperature of the low temperature mother liquor prepared for the first time is 40 ℃; 3 - =1:1.2; sodium nitrate and potassium chloride reaction constant temperature conversion temperature is 90 ℃, time is 20 minutes; the solid-liquid separation temperature in the slurry is 90 ℃, the temperature of hot water for high-temperature salt rinsing is also 90 ℃, high-temperature salt Potassium content in it drops to 1.21%, and potassium nitrate vacuum crystallization cold analysis temperature is 35 ℃; Others are with embodiment 1.

[0036] Compared with the traditional process, this embodiment can save about 21% of water and about 12% of energy. The content of potassium nitrate in the product meets the requirements of the national standard (GB / T1918-1998), the total yield of potassium ions is 96.34%, and the total yield of nitrate ions is 98.27%.

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Abstract

A vacuum crystallization process uses the sodium nitrate to transform the potassium chloride for the production of the potassium nitrate. The process comprises the following steps: (1) a first time low temperature mother liquid is prepared according to a corresponding phase diagram; (2) the sodium nitrate and the potassium chloride are added by proportion; and the constant temperature conversion is processed at 75-90 Celsius system; (3) the slurry is precipitated at 75-90 Celsius system until the solid percentage reaches 30%-45%, the crystallized high temperature salt is separated through centrifugation and the clear liquid enters into a vacuum crystallizer after filtration; (4) the high temperature salt is washed and the washing liquid is directly sent into the vacuum crystallizer; (5) the cold separation temperature of the vacuum crystallizer is controlled at 25-40 Celsius system, and the potassium nitrate crystal is precipitated; (6) the slurry is pumped into a slurry elevated slot after vacuum crystallization, the slurry is introduced into a centrifuge for the centrifugal separation to obtain the primary product of potassium nitrate; (7) the primary product of potassium nitrate is washed, re-dried and packaged. The invention has a convenient proportion, a mild isolation and transformation condition and a short production process, which can save more than 18% water and more than 20% energy. The operation of the invention is simple, and the process is easy to realize the continuous production and automatization. The invention also has a low production cost and good economic benefits.

Description

technical field [0001] The invention relates to a production process of potassium nitrate, in particular to a production process for preparing potassium nitrate through double decomposition reaction with sodium nitrate and potassium chloride. Background technique [0002] Potassium nitrate is a colorless transparent orthorhombic crystal or powder or granule, and is an important inorganic chemical product. [0003] Used as a chemical fertilizer, its advantage is that it is completely composed of effective plant nutrients. The total content of potassium and nitrogen can reach 60%, and it is easily absorbed by plants. There is no residue after application. It is a high-quality chlorine-free potassium and nitrogen compound fertilizer. High-quality fertilizer for chlorine-avoiding crops such as tobacco, coffee, tomato, grape, citrus, gardening, flowers, potato, avocado, tea, etc., and has good physical and chemical properties. It is known as the "third-generation potassium fertil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D9/14
Inventor 汤建良贺其华李昱昀戴斌联刘利鹏茆晓宝郝建委顾健
Owner CHANGSHA DESIGN & RES INST OF CHEM IND MIN
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