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A method for preparing crystal type II ammonium polyphosphate with thiourea as condensation agent

A technology of ammonium polyphosphate and condensing agent, which is applied in the fields of chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems that the preparation method of crystalline type II ammonium polyphosphate has not been reported in this respect, and achieves easy-to-implement process and low cost The effect of low cost and easy availability of raw materials

Active Publication Date: 2018-11-06
WUHAN INSTITUTE OF TECHNOLOGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In short, the main condensing agent for preparing ammonium polyphosphate at present is mainly P 2 o 5 , urea, melamine, etc., and the preparation method of crystalline type II ammonium polyphosphate using thiourea as a condensation agent has not been reported in this regard

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add 46.00 grams of ammonium dihydrogen phosphate and 21.31 grams of thiourea into the reactor, keep the temperature within 220°C and react for 25 minutes, after solidification, pulverize, heat up to 250°C and stir, and replace the reactor with a dry air flow rate of 1L / min The sulfide produced in the sulfide, time 10min; continue to heat up to 280 ° C and stir, feed wet ammonia (dry air flow rate is 1L / min into the mass fraction of 3% ammonia water to prepare, change the ammonia water every 20min), crystal form The conversion time is 1h, the temperature is lowered to room temperature under the protection of a wet ammonia atmosphere, pulverized and ground to obtain crystalline type II ammonium polyphosphate.

Embodiment 2

[0027] Add 46.01 grams of ammonium dihydrogen phosphate and 24.36 grams of thiourea into the reactor, keep the temperature within 230°C and react for 20 minutes, after solidification, pulverize, heat up to 260°C and stir, and the dry air flow rate is 1.5L / min to replace the reaction Sulfide produced in the still, time 5min; continue to heat up to 290 ℃ and stir, pass into wet ammonia gas (dry air flow rate is 2L / min pass into mass fraction and be 6% ammonia water preparation, change ammonia water once every 20min), crystallization The conversion time is 3 hours, the temperature is lowered to room temperature under the protection of wet ammonia atmosphere, pulverized and ground to obtain crystalline type II ammonium polyphosphate.

Embodiment 3

[0029] Add 23.01 grams of ammonium dihydrogen phosphate and 30.50 grams of thiourea into the reactor, and keep the temperature within 210°C for 30 minutes to react. After solidification, pulverize, heat up to 270°C and stir, and the dry air flow rate is 2L / min to replace the reactor. The sulfide produced in the sulfide, time 2min; continue to heat up to 300 ° C and stir, feed wet ammonia (dry air flow rate is 2L / min into the mass fraction of 6% ammonia water to prepare, change the ammonia water every 20min), crystal form The conversion time is 1h, the temperature is lowered to room temperature under the protection of a wet ammonia atmosphere, pulverized and ground to obtain crystalline type II ammonium polyphosphate.

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Abstract

The invention relates to a novel method for preparing crystal-II ammonium polyphosphate with a thiourea as a condensing agent. The novel method includes the steps of mixing ammonium dihydrogen phosphate with the thiourea evenly, and heating the raw materials to undergo fusion, foaming and solidification; pulverizing, continuing to heat with stirring, and continuously using dry air for replacing sulfide gas produced through reaction; continuing to heat, feeding wet ammonia gas with stirring continuously, ammoniating to achieve crystal phase transformation to obtain a product, decreasing the temperature to the room temperature under the protection of the same wet ammonia gas, pulverizing and grinding to obtain the crystal-II ammonium polyphosphate. The novel method has the advantages that the method is simple in preparation process, easily available to raw materials, low in cost and easy in implementation of technologies; compared with a method adopting urea as a condensing agent, the method with the thiourea as the condensing agent is less in material consumption, free of many other byproducts such as melamine, high in product purity and low in corrosivity under the same conditions.

Description

technical field [0001] The invention relates to the field of polymerization reaction, in particular to a new method for preparing crystalline type II ammonium polyphosphate by using thiourea as a condensation agent. Background technique [0002] Ammonium polyphosphate (ammonium polyphosphate), the English abbreviation is APP, and its general formula is (NH 4 ) n+2 P n o 3n+1 , when n is large enough, it can be written (NH 4 PO 3 ) n : Ammonium polyphosphate is also called ammonium polyphosphate or polycondensed ammonium phosphate (APP for short), and its appearance is white powder, containing nitrogen (N) ≥ 12%, containing phosphorus pentoxide (P 2 o 5 )≥68%, it is a kind of polyphosphate containing N and P, it contains two elements of phosphorus and nitrogen at the same time, interacts with each other and is flame retardant, and has good flame retardant performance. [0003] At present, it is known that there are 6 crystal forms of APP from I to VI, mainly of type I...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/40
CPCC01B25/405C01P2002/72C01P2002/82C01P2006/80
Inventor 丁一刚王毕德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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