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A method for preparing α-type high-strength gypsum from phosphogypsum

A high-strength gypsum and phosphogypsum technology, applied in the field of building materials, can solve problems such as low strength, limited product application range, and large water demand, and achieve the effects of low cost, superior cost performance, and small water demand

Active Publication Date: 2020-10-02
湖北远固新型建材科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the hemihydrate gypsum prepared by this method has tiny crystals and is long rod-shaped or even needle-shaped. The standard consistency requires a large amount of water and low strength, which limits the scope of application of the product.

Method used

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  • A method for preparing α-type high-strength gypsum from phosphogypsum

Examples

Experimental program
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Effect test

Embodiment 1

[0014] A method for preparing α-type high-strength gypsum from phosphogypsum, which comprises the following steps: 1) neutralizing phosphogypsum: adding P 2 o 5 Neutralize the quicklime with the sum of F, and age for 1d; 2) Prepare a composite crystal form control agent: weigh the ternary organic acid at a mass ratio of 0.05% of phosphogypsum, and weigh it at a mass ratio of 0.75% of phosphogypsum High-valent sulfate, mix the two and dissolve in water at 80°C to make a compound crystal form control agent; 3) Prepare thick phosphogypsum slurry: mix the compound crystal form control agent and water at a solid-to-liquid ratio of 4:1 Put it into the neutralized phosphogypsum to make a thick slurry; 4) Autoclave: spread the prepared slurry layer by layer according to the thickness of 5mm, put it into the autoclave, and keep the temperature at 120°C for 6h; 5 ) Drying and ball milling: Dry the autoclaved material at 120°C and ball mill it for 10 minutes to obtain α-type high-streng...

Embodiment 2

[0019] A method for preparing α-type high-strength gypsum from phosphogypsum, which comprises the following steps: 1) neutralizing phosphogypsum: adding P 2 o 5 Neutralize the quicklime with the sum of F, and age for 1d; 2) Prepare a composite crystal form control agent: weigh the ternary organic acid at a mass ratio of 0.01% of phosphogypsum, and weigh it at a mass ratio of 0.5% of phosphogypsum High-valent sulfate, mix the two and dissolve in water at 85°C to make a composite crystal form control agent; 3) Prepare thick phosphogypsum slurry: mix the composite crystal form control agent and water at a solid-to-liquid ratio of 2:1 Put it into the neutralized phosphogypsum to make a thick slurry; 4) Autoclave: spread the prepared slurry layer by layer according to the thickness of 15mm, put it into the autoclave, and keep the temperature at 150°C for 3h; 5 ) Drying and ball milling: Dry the autoclaved material at 150°C and ball mill it for 10 minutes to obtain α-type high-stre...

Embodiment 3

[0021] A method for preparing α-type high-strength gypsum from phosphogypsum, which comprises the following steps: 1) neutralizing phosphogypsum: adding P 2 o 5 Neutralize the quicklime with the sum of F, and age for 1d; 2) Prepare a composite crystal form control agent: weigh the ternary organic acid at a mass ratio of 0.5% of phosphogypsum, and weigh it at a mass ratio of 2% of phosphogypsum High-valent sulfate, mix the two and dissolve in water at 90°C to make a compound crystal form control agent; 3) Prepare thick phosphogypsum slurry: mix the compound crystal form control agent and water at a solid-to-liquid ratio of 3:1 Put it into the neutralized phosphogypsum to make a thick slurry; 4) Autoclave: spread the prepared slurry layer by layer according to the thickness of 10mm, put it into the autoclave, and keep the temperature at 130°C for 4h; 5 ) Drying and ball milling: Dry the autoclaved material at 130°C and ball mill it for 10 minutes to obtain α-type high-strength ...

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Abstract

The invention relates to a method for preparing alpha-type high-strength gypsum from phosphogypsum, belonging to the technical field of building materials. The method for preparing alpha-type high-strength gypsum from phosphogypsum is characterized by employing a semi-liquid-phase process and comprising the following steps: 1) blending phosphogypsum with quicklime with an amount identical to the sum of P2O5 and F in the phosphogypsum so as to neutralize the phosphogypsum and then carrying out aging for 1 d ; 2) weighing, on the basis of the total mass of the phosphogypsum, 0.01-0.5% of ternary organic acid and 0.5-2% of hypervalent sulfate, mixing the ternary organic acid and the hypervalent sulfate, and dissolving the obtained mixture in water with a temperature of 80-90 DEG C so as to prepare a composite crystal-type control agent; 3) adding the composite crystal-type control agent and water in a solid-liquid ratio of 4: 1 to 2: 1 into the neutralized phosphogypsum so as to form thick slurry; and 4) spreading the prepared slurry in an autoclave in layers, each layer being 5-15 mm thick, carrying out constant-temperature treatment at 120-150 DEG C for 3-6h, and then carrying out drying and ball-milling so as to obtain alpha-type high-strength gypsum powder. With the method in the invention, the prepared alpha-type high-strength gypsum is in the form of a short-column-like crystal with stable quality, and has 2-hour flexural strength of 4.9 MPa and drying compressive strength of 32.3 MPa; and obvious social, environmental and economic benefits are obtained.

Description

technical field [0001] The invention relates to a method for preparing alpha-type high-strength gypsum by using phosphogypsum, which belongs to the technical field of building materials. Background technique [0002] Phosphogypsum is mainly an industrial by-product of phosphoric acid produced by wet process in phosphorous chemical enterprises. About 4-5 tons of phosphogypsum is emitted from 1 ton of phosphoric acid produced by wet process. In 2004, the emission of phosphogypsum in my country has exceeded 22 million tons, and with the increasing demand for phosphoric acid and ammonium phosphate in industry and agriculture, the emission of phosphogypsum is also increasing. The Implementation Plan points out that in 2010, the emission of phosphogypsum in my country has reached about 60 million tons. The open-air stacking of phosphogypsum not only occupies a large area of ​​land, but also pollutes the environment. The main component of phosphogypsum is dihydrate gypsum (CaSO 4...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B11/26
CPCC04B11/26
Inventor 李国刚刘让新毕春梅
Owner 湖北远固新型建材科技股份有限公司
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