Technique for preparing sodium hexametaphosphate from wet method phosphoric acid

A technology of sodium hexametaphosphate and preparation process, applied in the field of preparation of sodium hexametaphosphate, can solve the problems of lack of enthusiasm for production, less variety of downstream products of sodium hexametaphosphate, and high price

Inactive Publication Date: 2008-02-13
SICHUAN HONGDA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But its disadvantage is that thermal phosphoric acid is prepared from yellow phosphorus. Because yellow phosphorus is expensive, the price is more than 10,000 yuan/ton, so the product cost is extremely high. Manufacturers are also unwilling to use it in large quantities, which greatly limits the application range of sodium hexametaphosphate. So far, there are few downstream products of

Method used

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  • Technique for preparing sodium hexametaphosphate from wet method phosphoric acid
  • Technique for preparing sodium hexametaphosphate from wet method phosphoric acid
  • Technique for preparing sodium hexametaphosphate from wet method phosphoric acid

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Embodiment 1

[0031] Referring to Fig. 1, the steps of this process are:

[0032] 1. Add sulfuric acid to phosphate rock powder, filter after stirring, and remove slag to obtain wet-process phosphoric acid. The P of this phosphoric acid is 2 o 5 Preferably ≥18%, so higher-grade phosphate rock should be selected to increase the yield of the product.

[0033] 2. Add 1000kg 18% P 2 o 5 Wet-process phosphoric acid is placed in the neutralization tank, and 109 kg of sodium hydroxide with a concentration of 98% is added to neutralize the reaction with phosphoric acid. The reaction temperature is controlled at 90°C and the reaction time is 50 minutes to prepare a slurry containing sodium dihydrogen phosphate. The reaction formula is as follows

[0034] h 3 PO 4 +NaOH==NaH 2 PO 4 +H 2 o

[0035] The slurry is a mixed slurry containing SO 2 2- , Fe 2 o 3 、Al 2 o 3 , MgO and other solid impurities.

[0036] 3. Filter the slurry, collect the clear liquid, and use the filter residue to ...

Embodiment 2

[0048] Difference with embodiment one is only, in the 2nd step, replaces sodium hydroxide with 133kg 98% sodium carbonate, reacts with phosphoric acid, and reaction formula is as follows

[0049] 2H 3 PO 4 +NaCO 3 ==2NaH 2 PO 4 +H 2 O+CO 2 ↑

[0050] All the other are identical with embodiment two.

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Abstract

The present invention discloses a sodium hexametaphosphate production technology, taking a wet-process phosphoric acid as the material. The steps are as following: A. Vitriol is added to a phosphorite to produce the wet-process phosphoric acid. B. A sodium hydroxid or a sodium salt is added to the wet-process phosphoric acid to produce a ground paste containing a sodium dihydrogen phosphate. C. The ground paste produced from the step B is filtrated and a clear liquid is collected. D. Ammonia is added to the clear liquid to produce the ground paste containing a composite NaH2PO4.NH3. E. The ground paste is cooled and concentrated to make the composite be crystal. F. The concentrated ground paste is filtrated to collect the composite crystal. G. The composite crystal is heated to make the NH3 in the composite volatilize. The sodium dihydrogen phosphate crystal is produced. H. the sodium dihydrogen phosphate crystal is converged, which produces the sodium hexametaphosphate. The advantage of invention is the low production cost.

Description

technical field [0001] The invention relates to a preparation process of sodium hexametaphosphate, in particular to a process for preparing sodium hexametaphosphate using wet-process phosphoric acid as a raw material. Background technique [0002] Sodium hexametaphosphate is an important chemical raw material, which is widely used in water treatment, oil drilling, mineral processing and chemical fiber. In recent years, the market demand has been increasing. [0003] The traditional process of preparing sodium hexametaphosphate at home and abroad is to use thermal phosphoric acid as raw material. The steps are: first neutralize thermal phosphoric acid and sodium hydroxide to obtain sodium dihydrogen phosphate, and then polymerize sodium dihydrogen phosphate to obtain The target product is sodium hexametaphosphate. The advantages of this process are that there are few impurities in the reactants, the process conditions are easy to meet, the reaction is sufficient, the product...

Claims

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Application Information

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IPC IPC(8): C01B25/445
Inventor 张凌吴三勇易遵礼欧运凤罗万林
Owner SICHUAN HONGDA
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