Method for removing impurities and whitening phosphogypsum

A technology of phosphogypsum and flotation agent, which is applied in the field of phosphorus chemical industry, can solve the problems that it is difficult to remove heavy impurities with large particle size, it is difficult to further improve the whiteness and purity, and it is difficult to deal with organic impurities and quartz impurities, so as to achieve wide industrial application Prospects, reduction and harmlessness, and the effect of facilitating recycling

Pending Publication Date: 2020-06-19
INST OF PROCESS ENG CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the cumulative production of phosphogypsum in my country has exceeded 300 million tons, and the stock has exceeded 250 million tons, but its utilization rate is less than 10%, and its stacking takes up a lot of land
[0005] The above processes have their own advantages and disadvantages in the application process, but they have their own limitations for different sources of phosphogypsum raw materials. For example, it is often difficult to completely remove some insoluble impurities by simple water washing, and it is difficult to remove heavy impurities with large particle sizes by simple positive flotation. Moreover, hydrophobic impurities are often mixed into the concentrate products and are difficult to remove. In addition, for the raw materials of the multi-layer inclusion mineral phase, it is

Method used

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  • Method for removing impurities and whitening phosphogypsum
  • Method for removing impurities and whitening phosphogypsum
  • Method for removing impurities and whitening phosphogypsum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] The dry base chemical composition of phosphogypsum in an enterprise is shown in Table 1 below.

[0060] Table 1 Dry basis chemical composition of phosphogypsum

[0061] Element SO 3

CaO SiO 2

P 2 o 5

al 2 o 3

Fe 2 o 3

K 2 o

TiO 2

MgO SrO Na 2 o

V 2 o 5

Cl content% 56.40 37.15 4.63 0.79 0.36 0.23 0.16 0.09 0.08 0.046 0.045 0.024 -

[0062] 1. Put phosphogypsum and 35% sulfuric acid into the reaction kettle with a mass ratio of 1:1.5, and stir;

[0063] 2. Heat to 85 degrees Celsius and keep for 1.5 hours;

[0064] 3. Add collector, the ratio is 1:2 based on phosphogypsum;

[0065] 4. After stirring evenly, let stand to separate the lower slurry layer;

[0066] 5. The upper layer is filtered to remove impurities and then recycled;

[0067] 6. The lower slurry is filtered and washed until neutral; the acidic filtrate is recycled;

[0068] 7. After the filter cake is wa...

Embodiment 2

[0074] The chemical composition of phosphogypsum dry basis impurities calculated by oxides in another enterprise is shown in Table 3 below.

[0075] Table 3 The chemical composition of phosphogypsum dry base impurities calculated by oxides

[0076] Element SiO 2

[0077] 1. Put phosphogypsum and 30% sulfuric acid into the reaction kettle with a mass ratio of 1:3, and stir;

[0078] 2. Heat to 90 degrees Celsius and keep for 1 hour;

[0079] 3. Add collector, the ratio is 1:3 based on phosphogypsum;

[0080]4. After stirring evenly, let stand to separate the lower slurry layer;

[0081] 5. The upper layer is filtered to remove impurities and then recycled;

[0082] 6. The lower layer slurry is added with extractant to continue the extraction, and the ratio is 1:5 in terms of phosphogypsum;

[0083] 7. The upper layer is filtered to remove impurities and then recycled;

[0084] 8. The lower slurry is filtered and washed until neutral; the acidic filtrate is re...

Embodiment 3

[0091] The fresh phosphogypsum from a phosphoric acid plant has a blue light whiteness of 25-30, and the scheme involved in this process is used for impurity removal and purification treatment:

[0092] 1. Phosphogypsum is subjected to pre-screening and particle size classification;

[0093] 2. Carry out water washing and flotation roughing for the products with qualified particle size (the dosage of flotation agent is 8-40kg / t dry ore);

[0094] 3. Flotation coarse concentrate is heated and atmospheric pressure acid leaching, and a small amount of collection aid is added to separate and enrich impurities in time;

[0095] 4. The slurry obtained by acid leaching is adjusted and then flotation and selected (the amount of flotation agent is 1-14kg / t dry ore);

[0096] 5. The impurity product obtained in each step is carried out by flotation and sweeping, and the calcium sulfate product mixed in the impurity is reclaimed;

[0097] 6. The calcium sulfate concentrate product is f...

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Abstract

The invention discloses a method for removing impurities and whitening phosphogypsum. The method comprises the following steps: (1) carrying out fineness rough machining on a phosphogypsum raw material; (2) carrying out acid leaching on the phosphogypsum obtained in the step (1) by using sulfuric acid, performing heating and keeping the temperature constant to obtain a material; (3) adding a flotation agent into the material obtained in the step (2), and carrying out flotation concentration separation; (4) feeding the slurry subjected to flotation separation obtained in the step (3) into gravity separation operation for impurity removal to obtain concentrate; and (5) filtering the concentrate obtained in the step (4), washing a filter cake, and drying and crushing the filter cake to obtainthe finished product purified gypsum. According to the method, high-whiteness and high-purity anhydrous calcium sulfate is prepared from phosphogypsum by utilizing a flotation/extraction/gravity separation process in a weakly acidic environment.

Description

technical field [0001] The invention relates to the technical field of phosphorus chemical industry, in particular to a method for removing impurities and whitening phosphogypsum, which uses flotation / extraction / re-election processes in an acidic environment to prepare high-whiteness, high-purity anhydrous calcium sulfate from phosphogypsum Methods. Background technique [0002] Phosphogypsum is the industrial waste produced during the reaction of phosphorus-containing minerals represented by apatite and sulfuric acid in the process of phosphoric acid production. Data surveys and related reports show that for every 1 ton of phosphoric acid (P 2 o 5 Total) will produce 4 to 5 tons of phosphogypsum. At present, the annual discharge of phosphogypsum in the world is more than 200 million tons, and the annual discharge of phosphogypsum by my country's phosphorus chemical industry is about 70 million tons, and it is increasing at a rate of 15% per year. At present, the cumulati...

Claims

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Application Information

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IPC IPC(8): C01F11/46C04B11/26
CPCC01F11/468C04B11/26
Inventor 李松庚范垂钢张明武刘润国
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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