Method for preparing dihydric phosphate

A technology of dihydrogen phosphate and phosphoric acid, which is applied in the direction of phosphate, phosphorus oxyacid, etc., can solve the problems of large aspect ratio, difficulty in large-scale production, small effective volume, etc., and achieve the effect of high production efficiency

Active Publication Date: 2009-01-14
GUIZHOU CHANHEN CHEM CO LTD
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  • Abstract
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Problems solved by technology

In order to solve the strong corrosion problem of phosphoric acid and hydrochloric acid mixed acid, the core reactor adopts a graphite reactor impregnated with polytetrafluoroethylene, which effectively solves the problem of corrosion of the equipment by the strong corrosive medium in the reaction system, but the system has the following disadvantages: 1. 1. The core reactor adopts graphite reactor. In order to strengthen the sealing of the reactor, the processing technology of graphite material is adopted as a whole. The le

Method used

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  • Method for preparing dihydric phosphate
  • Method for preparing dihydric phosphate
  • Method for preparing dihydric phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] will contain K 2 O 59.7%; Cl - 46.73% KCl was added to the P 2 o 5 24.88% phosphoric acid solution, stir evenly in the batching tank, adjust H 3 PO 4 The molar ratio of / KCl was 1.3. Transport the feed liquid to the spray drying tower for atomization, use high-temperature air for heating, control the feed volume of the atomizer and the temperature of the inlet air, and detect that the inlet temperature of the atomization drying tower is 700°C, and the outlet temperature of the tower is 400°C. At this temperature, potassium chloride and phosphoric acid complete the double decomposition reaction, and the bottom material flows into the hydrolysis tank, and potassium hydroxide aqueous solution is added to the hydrolysis tank, and the temperature of the hydrolysis tank is detected to be 108°C, so that potassium pyrophosphate is hydrolyzed into potassium dihydrogen phosphate, and the hydrogen oxidation is controlled. The amount of potassium added is such that the pH of t...

Embodiment 2

[0033] A 35% potassium chloride solution was added to the P 2 o 5 40.3% phosphoric acid solution, stir evenly in the batching tank, adjust H 3 PO 4 The / KCI molar ratio is 2.0. Transport the feed liquid to the spray drying tower for atomization, use high-temperature air for heating, control the feed volume of the atomizer and the temperature of the inlet air, and detect that the inlet temperature of the atomization drying tower is 450°C, and the outlet temperature of the tower is 298°C. Potassium chloride and phosphoric acid complete the metathesis reaction at this temperature, and the bottom material flows into the hydrolysis tank, and potassium carbonate aqueous solution is added to the hydrolysis tank, and the temperature of the hydrolysis tank is detected to be 120°C, so that the generated potassium pyrophosphate is hydrolyzed into potassium dihydrogen phosphate, and controlled The amount of potassium carbonate added is such that the pH of the hydrolyzate is 4.4-4.6, th...

Embodiment 3

[0037] Add industrial sodium chloride with a content of 98.9% to the 2 o 5 23.98% phosphoric acid solution, stir evenly in the batching tank, adjust H 3 PO 4 The / NaCI molar ratio was 1.05. Transport the feed liquid to the spray drying tower for atomization, use high-temperature air for heating, control the feed volume of the atomizer and the temperature of the inlet air, and detect that the inlet temperature of the atomization drying tower is 430°C, and the outlet temperature of the tower is 250°C. At this temperature, sodium chloride and phosphoric acid complete the metathesis reaction, the bottom material flows into the hydrolysis tank, and sodium hydroxide aqueous solution is added to the hydrolysis tank, and the temperature of the hydrolysis tank is detected to be 96°C, so that the generated sodium pyrophosphate is hydrolyzed into sodium dihydrogen phosphate, Control the amount of sodium hydroxide added so that the pH of the hydrolyzate is 4.1-4.7, the hydrolyzate that...

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Abstract

The invention discloses a method of producing dihydric phosphate, which essentially comprises steps as follows: firstly, chloride is mixed with excessive phosphoric acid in order to obtain material liquid; secondly, the material liquid is added into the spray dryer to atomize into tiny droplets; thirdly, the droplets are instantaneously contacted and heated with as much hot air as is sufficient to enable double decomposition reaction between chloride and phosphoric acid to happen, so that hydrogen chloride gas escapes through the double decomposition reaction between chloride and phosphoric acid, and the remaining reaction products are hydrolyzed, the pH value thereof is regulated, and a dihydric phosphate product is obtained after cooling and crystallization. The production method has technical advantages that the shortcomings of prior art can be overcome, the spray dryer is adopted as a core reactor to atomize the material liquid into small droplets to be contacted with the high-temperature hot air, the specific surface area of evaporation is maximum, so that the escaping time of HCl and the water vapor is 3 to 8 seconds only, the reaction conversion rate reaches up to 97 percent, the cost of raw materials can be significantly reduced, the material liquid continues to be in and out, the reaction device is simple and practical, so that large-scale industrialization production can be achieved.

Description

Technical field: [0001] The invention relates to the field of production of dihydrogen phosphate, in particular to a method for producing dihydrogen phosphate by atomizing phosphoric acid and chloride at high temperature for metathesis reaction. Background technique: [0002] At present, the traditional production method of dihydrogen phosphate mainly uses hydroxide and phosphoric acid to carry out acid-base neutralization reaction, such as: the production of potassium dihydrogen phosphate is to select potassium hydroxide and phosphoric acid as raw materials, and directly produce Make potassium dihydrogen phosphate, although this method is simple, potassium hydroxide raw material is expensive, and production cost is high, and product added value is low. Other methods such as: Potassium chloride and phosphoric acid metathesis low-temperature extraction method, the loss of extractant is serious, the price is high, and the environmental pollution is heavy; Phosphate metathesis ...

Claims

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Application Information

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IPC IPC(8): C01B25/26
Inventor 李进李光明王佳才邹建刘义明
Owner GUIZHOU CHANHEN CHEM CO LTD
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