Process for preparing food-grade potassium metaphosphate by virtue of melting arsenic removal solid potassium dihydrogen phosphate

A technology of potassium dihydrogen phosphate and potassium metaphosphate, which is applied in phosphorus compounds, inorganic chemistry, non-metallic elements, etc., can solve the problems of heavy process, difficulty in removing arsenic and arsenic content to ppm level, and unfavorable environmental protection in wastewater discharge. The process is simple, the effect of avoiding difficult utilization, and no waste water discharge

Active Publication Date: 2017-01-25
WUHAN INSTITUTE OF TECHNOLOGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, it is difficult to remove arsenic by chemical precipitation to reach the ppm level, and the potassium dihydrogen phosphate solution needs to be crystallized, filtered, and dried before it can be used in the production of food-grade potassium metaphosphate. Environmental friendly

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Weigh 136.09g of potassium dihydrogen phosphate (arsenic content 5.33ppm) in a 500mL three-necked flask, heat it to a molten state (230°C to 250°C) on an electronic universal furnace, then transfer it to a constant temperature electromagnetic heater, and adjust the stirring The speed is 150rpm, the temperature is slowly raised to a molten state, the inserted temperature count value is read, 0.03mol hydrochloric acid is added dropwise, and the reaction is carried out for 30 minutes to obtain potassium dihydrogen phosphate after removing arsenic. The arsenic content of the potassium dihydrogen phosphate is 2.82ppm. Continue heating to 500°C with a heating rate of 15°C / min and a reaction time of 180min to obtain potassium metaphosphate. The present invention uses an inductively coupled plasma emission spectrometer to test the trace amount of arsenic. Since the arsenic content is very low, this method is the one with the least interference among various analysis methods, and...

Embodiment 2

[0024] Weigh 136.09g of potassium dihydrogen phosphate (arsenic content 5.33ppm) in a 500mL three-necked flask, heat it to a molten state (230°C to 250°C) on an electronic universal furnace, then transfer it to a constant temperature electromagnetic heater, and adjust the stirring The speed is 250rpm, and the temperature is slowly raised to a molten state. Read the inserted temperature count value, add 0.03mol hydrochloric acid dropwise, and react for 30 minutes to obtain potassium dihydrogen phosphate after removing arsenic. The arsenic content of the potassium dihydrogen phosphate is 2.65ppm. Continue heating to 500°C with a heating rate of 15°C / min and a reaction time of 180min to obtain potassium metaphosphate. The present invention uses an inductively coupled plasma emission spectrometer to test the trace amount of arsenic. Since the arsenic content is very low, this method is the one with the least interference among various analysis methods, and has high analysis accurac...

Embodiment 3

[0026] Weigh 136.09g of potassium dihydrogen phosphate (arsenic content 5.33ppm) in a 500mL three-necked flask, heat it to a molten state (230°C to 250°C) on an electronic universal furnace, then transfer it to a constant temperature electromagnetic heater, and adjust the stirring The speed is 350rpm, the temperature is slowly raised to a molten state, the inserted temperature count value is read, 0.03mol hydrochloric acid is added dropwise, and the reaction is carried out for 30 minutes to obtain potassium dihydrogen phosphate after arsenic removal, and the arsenic content of the potassium dihydrogen phosphate is 2.44ppm. Continue heating to 500°C with a heating rate of 15°C / min and a reaction time of 180min to obtain potassium metaphosphate. The present invention uses an inductively coupled plasma emission spectrometer to test the trace amount of arsenic. Since the arsenic content is very low, this method is the one with the least interference among various analysis methods, ...

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Abstract

The invention relates to a process for preparing food-grade potassium metaphosphate by virtue of arsenic removal on molten potassium dihydrogen phosphate. The process comprises the following steps: under a heating and stirring condition, reacting haloid acid with molten potassium dihydrogen phosphate so as to generate an arsonium halide substance with a low boiling point, performing subliming, directly further heating molten potassium dihydrogen phosphate subjected to arsenic removal for dehydration polymerization reaction, thereby obtaining the food-grade potassium metaphosphate. By virtue of adopting the method, the process has the beneficial effects that 1) the method is convenient in operation process, and solid-phase molten potassium dihydrogen phosphate subjected to arsenic removal is capable of facilitating preparation of the food-grade potassium metaphosphate; 2), the arsenic removal process can be connected with a subsequent potassium polymetaphosphate process, and two workshop sections are seamlessly connected, so that heating melting after cooling of the potassium dihydrogen phosphate subjected to arsenic removal can be avoided, and energy losses brought by repeated heating are reduced; 3) the process for preparing the food-grade potassium metaphosphate by virtue of melting arsenic removal on potassium dihydrogen phosphate does not need crystallization and filtration processes and is free from waste water discharge; and 4), the viscosity of the food-grade potassium metaphosphate is up to 6.5mPa.s-15mPa.s.

Description

technical field [0001] The invention belongs to the technical field of polymerization reaction, and in particular relates to a process for preparing potassium metaphosphate by removing trace arsenic from molten state potassium dihydrogen phosphate. Background technique [0002] Potassium metaphosphate is a highly polymerized straight-chain polyphosphate. There may be a small amount of potassium trimetaphosphate and potassium tetrametaphosphate in a ring structure, and it is a colorless to white glassy block or Flaky, or white fibrous crystal or powder. [0003] At present, the production technology of domestic potassium metaphosphate is mainly aimed at agricultural fertilizer products and binders, and the products only focus on meeting certain specific industrial indicators. The purity is low, and it cannot be applied to the field of food additives, so the price of the product is relatively low. . In addition, potassium dihydrogen phosphate, the raw material for the curren...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/445
CPCC01B25/445C01P2006/22C01P2006/80
Inventor 丁一刚骆万智龙秉文邓伏礼刘生鹏刘东杨昌炎何俊
Owner WUHAN INSTITUTE OF TECHNOLOGY
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