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Method for producing electron-level phosphoric acid

An electronic-grade phosphoric acid and phosphoric acid technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., to achieve mild operating conditions, good economic benefits, and high productivity

Active Publication Date: 2009-10-21
WENGFU (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In fact, the electronic-grade phosphoric acid prepared by this method has the best heavy metal content of 1ppm, which can only meet the requirements of MOS-grade electronic-grade phosphoric acid, and cannot meet the requirements of higher-level electronic-grade phosphoric acid products.

Method used

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  • Method for producing electron-level phosphoric acid

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0024] Preparation of seed crystals:

[0025] Take 500g of electronic-grade phosphoric acid and add it to a 1000mL three-port boron glass crystallizer, connect it with a stirrer, a dryer, and a cooling system, rapidly cool down to ≤-25°C under stirring, and obtain seed crystals by explosive crystallization for use.

Embodiment 1

[0027] Take 600g mass ratio of 85% thermal food-grade phosphoric acid and add it to a 1000mL three-port boron glass crystallizer, connect the stirrer, drying pipe, cooling system, start stirring, the stirring rate is 400rpm, control the temperature of the material at 20 °C and add the above Prepare 90g of phosphoric acid crystals as seed crystals, then gradually cool down at a cooling rate of 4°C / h for 1h, then cool down at a rate of 2°C / h for 2h, cool to 12°C, grow crystals for 2h, and then centrifugally filter to obtain crystals for use in An appropriate amount of high-purity water or high-purity phosphoric acid solution was washed to finally obtain 415 g of phosphoric acid hemihydrate crystals, with a phosphoric acid yield of 64.22%. The test results are shown in Table 1.

[0028] Table 1 Embodiment 1 crystal product impurity content

[0029] Index Item

Impurity concentration

Index Item

Impurity concentration

Aluminum (Al)

0.5ppm

Iron (Fe...

Embodiment 2

[0034] Take 600g of 80% wet-purified phosphoric acid and add it to a 1000mL boron glass crystallizer, connect the stirrer, drying pipe, and cooling system, start stirring at a stirring rate of 400rpm, and add 120g of phosphoric acid crystals prepared above when the temperature drops to 6°C to make Seed crystals, keep the temperature for 1h, then cool down at a cooling rate of 8°C / h for 1h to -2°C, then cool down at a cooling rate of 4°C / h for 2.5h to -12°C, keep warm for 1h, and then centrifugally filter to obtain crystals with an appropriate amount After washing with high-purity water or high-purity phosphoric acid solution, 349 g of phosphoric acid hemihydrate crystals were finally obtained, and the yield of phosphoric acid was 54.25%.

[0035] Take 300g of the above-mentioned phosphoric acid hemihydrate crystal and add it to a 500mL boron glass crystallizer, add 20g of ultrapure water, connect the stirrer, drying pipe, and cooling system, start stirring, and the stirring rat...

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Abstract

The invention relates to a production method of electronic-grade phosphoric acid. The raw material acid adopts thermal phosphoric acid or wet purification acid, wherein the H3PO4 concentration-mass ratio is 80-85%, and the crystallization process: at 15-30°C, the amount of seed crystals added is 10 ~20%, after keeping the temperature for 0.1h~3h, use the method of gradient cooling to cool down to -15~15℃, keep warm, grow crystals, and then filter to obtain phosphoric acid hemihydrate crystals, and send the mother liquor to the wet process phosphoric acid purification device as raw material , the crystals are washed with high-purity water or high-purity phosphoric acid solution, and the obtained crystals are used as raw materials for recrystallization. This method has mild operating conditions and does not require special crystallization equipment. The obtained phosphoric acid hemihydrate crystals have regular appearance and an average particle size of more than 0.5mm. There is less wrapping of impurities, and the total content of fourteen kinds of cations in the obtained product does not exceed 0.6ppm after testing, which meets the requirements of the electronic-grade phosphoric acid index. The method has low production cost and high productivity, and is a production method with good economic benefits.

Description

technical field [0001] The patent of the present invention relates to a method for purifying phosphoric acid, in particular to a method for purifying phosphoric acid by cooling crystallization to produce high-purity electronic-grade phosphoric acid. Background technique [0002] Electronic-grade phosphoric acid is mainly used as a cleaning agent and etchant for electronic components in the promising IT industry. Its purity has a great impact on the product rate, electrical performance and reliability of electronic components. [0003] Korea's Kim CU and others developed a crystallization method to produce high-purity phosphoric acid technology. They first prepared the seed crystals in a container equipped with a stirrer, scraper and jacket, and then scraped the seed crystals from the wall of the container with a scraper, and continuously entered the next crystallizer equipped with a stirrer and jacket, The seed crystal grows and crystallizes in the crystallizer, and then en...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/234
Inventor 李天祥解田刘飞杨丽萍张群田言
Owner WENGFU (GRP) CO LTD
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