Fluorine-containing waste gas utilization method in phosphorus fertilizer production

A waste gas and phosphate fertilizer technology, applied in separation methods, chemical instruments and methods, and separation of dispersed particles, can solve problems such as product quality, economic competition, and limited fluorite reserves

Inactive Publication Date: 2006-01-18
夏克立
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Since the above method is still unable to compete with the traditional production method using fluorite as raw material in terms of product quality and economy, so far the fluorine chemical products including aluminum fluoride and cryolite are still mainly used in addition to sodium fluorosilicate. produced from fluorite
However, the reserves of fluorspar are limited and are already facing depletion. In view of the importance of fluorspar resources, the country identified fluorspar as a strategic resource and restricted exports a few years ago. Fluorine in phosphate rock is the only fluorine resource that may replace fluorspar. , it mainly exists in fluorine-containing waste gas, and it is an extremely cheap fluorine resource. As long as there is an economical and effective recycling method, it is difficult for fluorine chemical products based on fluorite to compete with it

Method used

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  • Fluorine-containing waste gas utilization method in phosphorus fertilizer production
  • Fluorine-containing waste gas utilization method in phosphorus fertilizer production
  • Fluorine-containing waste gas utilization method in phosphorus fertilizer production

Examples

Experimental program
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Effect test

Embodiment 1

[0044] Bring the concentration to ~20% NH 4 The F solution is introduced into the exhaust gas absorption system of the chemical formation chamber with an annual output of 100,000 tons of ordinary calcium for absorption, and the concentration ~ 34% (NH 4 ) 2 SiF 6 Solution, add it and liquid ammonia to the ammoniator at the same time and control its pH value at 7.2-7.5, feed liquid ammonia into the ammoniator and control the final pH value of the ammoniation reaction to be above 8, and the temperature at 50-70°C In between, the obtained slurry was aged for 1 hour and then filtered, washed countercurrently with clean water until the eluate was close to neutral, and the filter cake was dried at 110°C to obtain a specific surface area of ​​110m 2 / g of precipitated silica (silica) product and a concentration of 40.6% NH 4 Ammonium fluoride solution of F; add concentration of 15% H in another reactor 2 SiF 6 Fluorosilicic acid, after preheating to 75°C, add a theoretical amoun...

Embodiment 2

[0049] The ammonium fluoroaluminate filter cake in Example 1 was dried at 110°C and then calcined at 550°C for 1.5 hours to obtain the aluminum fluoride product. The gas produced by calcining was absorbed to obtain a concentration of 42.6% NH 4 The ammonium fluoride solution of F is returned to react with the aluminum fluoride solution in Example 1 to produce ammonium fluoroaluminate for the production of aluminum fluoride again. The product quality is shown in Table 2.

[0050] Table 2. Aluminum fluoride national standard and process product quality of the present invention

[0051]

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Abstract

The present invention relates to utility method for fluoric gases in phosphoric acid manufacture. Bring directly the ammonium fluoride and / or ammonia in system to obtain solution with (NH4)2SiF6 25~37%; use ammonia to ammoniate the solution and prepare deposition of silicon dioxide (white carbon black) with specific surface area of 100í½180m2 / g and NHF solution with concentration of 30~45%; use the two solutions to react, filter, wash and obtain filter cake; based on it, prepare cryolite and aluminun fluoride with high quality and low cost.

Description

technical field [0001] The invention is a production method for comprehensively utilizing fluorine-containing waste gas in phosphate fertilizer production, belonging to the field of inorganic chemical industry, and specifically relates to a production method for producing cryolite, aluminum fluoride and by-product white carbon black by using fluorine-containing waste gas in phosphate fertilizer production . Background technique [0002] As we all know, phosphate rock contains a certain amount of fluorine and silicon compounds. When processing phosphate rock to produce ordinary calcium superphosphate, extract phosphoric acid, heavy calcium, etc., part of the fluorine in the phosphate rock reacts with silicon to form tetrafluoride The form of silicon and hydrogen fluoride escapes. In order to eliminate the impact of this "fluorine-containing waste gas" on the environment, it is mostly absorbed by water to obtain fluosilicic acid, which is then further processed and utilized. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/68B01D53/78
Inventor 夏克立
Owner 夏克立
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