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Method for preparing industrial grade and food grade phosphoric acid by wet method phosphoric acid

A wet-process phosphoric acid, industrial-grade technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of excessive sodium ions in the purification acid, serious organic phase entrainment in the acid phase, increased process and purification costs, etc. Achieve complete removal, reduce energy consumption, reduce density and viscosity

Inactive Publication Date: 2005-06-01
SICHUAN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its weak point is: 1. it is uneconomical to increase the extraction rate by adding sulfuric acid during extraction, which will increase the difficulty of subsequent removal of sulfate radicals. To make sulfate radical removal more thorough, it is necessary to increase the consumption of NaOH The amount of returning acid for washing will also increase accordingly, which reduces the efficiency of the device
③ It is not easy to control the removal of arsenic in the purified acid. Sodium sulfide, the arsenic removal agent, is soluble in phosphoric acid. A little carelessness will lead to excessive sodium ions in the purified acid
④ Density of tributyl phosphate (0.97g / cm 3 ) is close to the density of water, and the viscosity increases a lot after extracting phosphoric acid. Without diluent, it will be difficult to separate the two phases, and the acid phase entrains the organic phase seriously. Therefore, the tributyl phosphate entrained in the raffinate acid phase must be recovered. Increased process and purification costs

Method used

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  • Method for preparing industrial grade and food grade phosphoric acid by wet method phosphoric acid
  • Method for preparing industrial grade and food grade phosphoric acid by wet method phosphoric acid
  • Method for preparing industrial grade and food grade phosphoric acid by wet method phosphoric acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Embodiment 1: Preparation of technical grade phosphoric acid

[0020] P 2 o 5

SO 4 2-

F

Fe

As

Heavy metals (as Pb)

Chroma

50.4％

3.5％

0.75％

0.3％

0.0014％

0.0025％

＞300

[0021] Continuous production, process steps such as figure 1 As shown, it includes pretreatment, desulfurization, filtration separation, extraction, deep desulfurization, washing, stripping and concentration in sequence.

[0022] (1) Pretreatment

[0023] The pretreatment is carried out in the pretreatment tank, and the desulfurization agent is phosphorus concentrate, according to the amount of SO in phosphoric acid 4 2- 1.1 times of the stoichiometric ratio is added; the defluorination agent is selected from sodium carbonate, and the addition is 1.2 times of the stoichiometric ratio of fluorine content in phosphoric acid; the decolorizing agent is selected from active carbon and diatomite, and the addition of active carbon i...

Embodiment 2

[0039] Embodiment 2: Preparation of food-grade phosphoric acid

[0040] In this embodiment, the composition of the raw material wet-process phosphoric acid used is the same as that in Embodiment 1. Continuous production, process steps such as figure 2 As shown, it includes pretreatment, desulfurization, filtration separation, extraction, deep desulfurization, washing, stripping, deep defluorination and concentration in sequence.

[0041] In the above process steps, except for the pretreatment, deep defluorination and concentration processes, other processes are the same as in Example 1.

[0042]The pretreatment is carried out in the pretreatment tank, and the desulfurization agent is phosphorus concentrate, according to the amount of SO in phosphoric acid 4 2- 1.2 times of the stoichiometric ratio is added; the defluorination agent is selected from sodium carbonate, which is 1.1 times of the stoichiometric ratio of the fluorine content in phosphoric acid; The amount of di...

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Abstract

A method for preparing industrial-grade phosphoric acid with wet-process phosphoric acid. The process steps include pretreatment, desulfurization, filtration and separation, extraction, deep desulfurization, washing, back-extraction and concentration; Fluorine agent and decolorizing agent, desulfurization, defluorination and decolorization are carried out in one process, the reaction temperature is 60-80°C, and the reaction time is 2-4 hours. The method of preparing food-grade phosphoric acid with wet-process phosphoric acid is to add a deep defluorination process on the basis of the above-mentioned process steps for preparing industrial-grade phosphoric acid, and the deep defluorination process is placed after the stripping process. This method simplifies the process, reduces energy consumption and saves costs.

Description

1. Technical field [0001] The invention belongs to the preparation method of industrial-grade phosphoric acid and food-grade phosphoric acid, and particularly relates to a process for purifying wet-process phosphoric acid into industrial-grade phosphoric acid or food-grade phosphoric acid by using a solvent extraction method using wet-process phosphoric acid as a raw material. 2. Background technology [0002] The preparation of industrial-grade phosphoric acid and food-grade phosphoric acid can be either hot-process phosphoric acid or wet-process phosphoric acid. Due to the high energy consumption of thermal phosphoric acid production, people are more willing to use wet-process phosphoric acid due to the increasing energy shortage. However, wet-process phosphoric acid contains high impurities and must be purified to meet the requirements of industrial-grade phosphoric acid and food-grade phosphoric acid. Regarding the purification of wet-process phosphoric acid, there are m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D11/04C01B25/234C01B25/237
Inventor 李军钟本和何浩明何秦杨三可黄美英陈亮
Owner SICHUAN UNIV
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