Method for preparing high-quality feed-grade calcium hydrophosphate by by-product waste acid of titanium dioxide

A technology of calcium hydrogen phosphate and titanium dioxide, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve environmental pollution and other problems

Active Publication Date: 2012-09-19
SICHUAN LOMON PHOSPHORUS CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a method for preparing feed grade calcium hydrogen phosphate by using waste acid produced by titanium dioxide, which can effectively solve the problems of waste

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] 1) Preparation of H 2 SO 4 The mass fraction is 35% (wt%) configuration acid

[0050] Be 98% (wt%) industrial sulfuric acid (its composition is: H 2 SO 4 98.0% (wt%), specific gravity 1.84, Fe 2 o 3 0.63% (wt%), Al 2 o 3 0.02% (wt%) and MgO 0.08% (wt%)) are mixed with the waste sulfuric acid obtained in the production process of titanium dioxide in the mixing tank to prepare a mixed acid, and the H in the mixed acid liquid phase 2 SO 4 The mass fraction of H is 36% (wt%), and after preparation, the slag is removed by filtration to obtain H 2 SO 4 The mass fraction is 35.14% (wt%) to configure acid, its specific gravity is 1.31, Fe 2 o 3 3.23% (wt%), Al 2 o 3 0.28% (wt%) and MgO0.36% (wt%)), spare.

[0051] 2) Preparation of Phosphate Slurry

[0052] Take 30t phosphate rock (phosphate rock composition: P 2 o 5 31.2%(wt%), CaO 43.66%(wt%), SO 3 2.98%(wt%), Fe 2 o 3 2.54% (wt%), Al 2 o 3 3.01% (wt%), MgO 2.51% (wt%) and H 2 O 8.0% (wt%)) is...

Embodiment 2

[0066] 1) Repeat steps 1)-3) of Example 1; the difference lies in the configuration of acid H 2 SO 4 The mass fraction is 55% (wt%)

[0067] 2) Leaching

[0068] Put the obtained 43.85t of repulped slurry into the leaching tank with a specification model of φ1500*300, and at the same time configure 15.94t of sulfuric acid with a mass fraction of 55%, 11t of concentrated sulfuric acid with a mass fraction of 98%, and back phosphoric acid (the phosphoric acid contained in it The mass fraction is 20wt%) 54.46 tons, add to the leaching tank and mix and stir. After stirring for 4 hours, a mixed slurry is obtained. The liquid phase temperature of the mixed slurry is 81.26°C, and the reaction rate is 97.03%. The mixed slurry The material contains 87.7t of phosphoric acid liquid (its liquid phase composition: P 2 o 5 248g / L, Ca 1.32g / L, F 14.75g / L, SO 3 30.29 g / L, Fe 2 o 3 5.08g / L, Al 2 o 3 is 14.45 g / L and MgO is 14.52g / L) and anhydrous phosphogypsum is 38.9t.

[0069] 3) ...

Embodiment 3

[0074] 1) Repeat the steps 1)-3) of Example 1; the difference is that the mass fraction of the configured acid is 80% (wt%)

[0075] 2) Leaching

[0076] Put the obtained 43.85t of repulped slurry into the leaching tank with a specification model of φ1500*300, and at the same time configure 10.96t of sulfuric acid with a mass fraction of 79.52%, 11t of concentrated sulfuric acid with a mass fraction of 98%, and back phosphoric acid (the phosphoric acid contained in it The mass fraction of the mixed slurry is 5wt%) 41.65 tons, which are added to the leaching tank and mixed and stirred. After stirring for 3 hours, a mixed slurry is obtained. The liquid phase temperature of the mixed slurry is 88 ° C and the reaction rate is 96.83%. The obtained mixed slurry The slurry contains 87.7t of phosphoric acid liquid (its liquid phase composition: P2O5 is 248.56g / L, Ca is 1.32g / L, F is 13.65g / L, SO 3 29.29 g / L, Fe 2 o 3 4.65g / L, Al 2 o 3 is 14.75 g / L and MgO is 13.52g / L) and anhydro...

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Abstract

The invention provides a method for preparing high-quality feed-grade calcium hydrophosphate by by-product waste acid of titanium dioxide, comprising the following steps of: enabling phosphorite slurry to pre-react; mixing with dilute sulphuric acid, concentrated sulfuric acid and water; and performing desulfurating, filtering, removing impurities, neutralizing, depositing and centrifugally drying on the obtained material. The method overcomes the problem that the titanium dioxide waste acid is difficult to recycle due to high impurity content; the quality of the obtained calcium hydrophosphate meets production requirement of the feed additive completely; and due to the waste produced by titanium dioxide, the method solves the pollution problem of waste sulfuric acid produced by titanium dioxide, develops new recycling path of the waste, reduces adding amount of the make-up water in the water balance of a leaching system due to low-concentration sulfuric acid, reduces water consumption for production, saves cost and improves the economic benefit.

Description

technical field [0001] The invention relates to the technical field of wet-process phosphoric acid, in particular to a preparation process of wet-process calcium hydrogen phosphate. Background technique [0002] At present, the production of phosphate is mainly based on sulfuric acid wet-process phosphoric acid. First, concentrated sulfuric acid and phosphate rock are mixed with acid leaching to generate phosphoric acid, and then phosphate is produced after impurity removal. There are mainly the following problems: the quality of phosphate rock is continuously declining, which reduces the quality of phosphate products; concentrated sulfuric acid will release a large amount of heat during phosphoric acid leaching, causing the acid leaching temperature to be too high, which affects the crystallization and filtration effect of phosphogypsum in the acid production process Therefore, cooling equipment is required to remove a large amount of heat energy. Now, if the low-level flas...

Claims

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Application Information

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IPC IPC(8): C01B25/32
CPCC01B25/32C01B25/322
Inventor 廖延武向书刚董禄银孙素
Owner SICHUAN LOMON PHOSPHORUS CHEM
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