A kind of pretreatment and application method of phosphogypsum

A phosphogypsum and pretreatment technology, applied in the field of phosphorus chemical industry, can solve the problems of large water consumption, high cost and high cost of the washing method, achieve the improvement of uniaxial compressive strength, improve the utilization rate of resources, and reduce the release of harmful components Effect

Active Publication Date: 2020-02-14
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Among the above methods, the water washing method and the natural aging method are simple to operate, but no matter whether water is used in the water washing method or rainwater is used in the natural aging method to treat phosphogypsum, it is easy to cause secondary pollution, and the water consumption of the water washing method is too large, which is not economical. ; Lime neutralization method is not easy to cause secondary pollution, but the cost is high, it is difficult to meet the economic and technical requirements of phosphogypsum filling, and too much lime addition will reduce the mechanical properties of phosphogypsum-based filling body; screening method, ball milling method, The calcination method is complex in operation and high in cost, and it is difficult to be popularized and applied in the filling process of phosphate rock production enterprises, and the ball milling method cannot fundamentally pretreat phosphogypsum

Method used

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  • A kind of pretreatment and application method of phosphogypsum
  • A kind of pretreatment and application method of phosphogypsum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Step 1: Weigh 3500g of phosphogypsum, 3713.5g of tap water and 126g of industrial heavy calcium powder into a container. The amount of industrial heavy calcium powder is 4% of the mass of phosphogypsum. Stir for 5 minutes at a speed of 200rpm with a mixer to obtain a phosphogypsum material slurry, at this time pH=3.03;

[0044] Step 2: Put the phosphogypsum slurry in step 1 to stand and age for 3 hours to fully react, and the pH at this time is 2.67.

[0045]Step 3: Add 787.5 g of gelling agent to the phosphogypsum slurry in the container in step 1 according to the mass ratio of phosphogypsum and gelling agent at a ratio of 4:1, and stir at 200 rpm for 30 to 45 minutes using a mixer to obtain Filling slurry with a mass concentration of 50%;

[0046] Step 4: pour the filling slurry in step 3 into a mold to prepare a filling sample.

Embodiment 2

[0048] Step 1: Weigh 3500g of phosphogypsum, 3839.5g of tap water and 252g of industrial heavy calcium powder into a container. The amount of industrial heavy calcium powder is 8% of the mass of phosphogypsum. Use a mixer to stir at a speed of 200rpm for 5min to obtain a phosphogypsum material Slurry, at this time pH=3.24;

[0049] Step 2: Put the phosphogypsum slurry in step 1 to stand and age for 3 hours to fully react, and the pH at this time is 3.38.

[0050] Step 3: Add 787.5 g of gelling agent to the phosphogypsum slurry in the container in step 1 according to the mass ratio of phosphogypsum and gelling agent at a ratio of 4:1, and stir at 200 rpm for 30 to 45 minutes using a mixer to obtain Filling slurry with a mass concentration of 50%;

[0051] Step 4: pour the filling slurry in step 3 into a mold to prepare a filling sample.

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Abstract

The invention belongs to the field of functional utilization of phosphorus chemical industry waste and specifically discloses a phosphogypsum pretreatment method. The phosphogypsum pretreatment methodis characterized by comprising the steps: mixing and pulpifying phosphogypsum, coarse whiting and water to obtain phosphogypsum slurry; ageing the phosphogypsum slurry to obtain pretreated phosphogypsum. The invention further discloses application of the pretreated phosphogypsum. The pretreated phosphogypsum can serve as filling aggregate. The inventor finds that performance of the pretreated phosphogypsum can be improved when the coarse whiting and ageing synergistic pretreatment are matched; for example, harmful ingredients in the pretreated phosphogypsum are fixed, and strength of the phosphogypsum utilized as mining filling aggregate in the application field is improved.

Description

technical field [0001] The invention relates to the field of phosphorus chemical industry, in particular to a method for preparing a filling body using industrial heavy calcium powder co-aged and pretreated phosphogypsum as aggregate. Background technique [0002] Phosphogypsum is a by-product of sulfuric acid decomposition of phosphate rock to produce phosphoric acid. Unlike ordinary tailings filling technology that uses inert tailings (mainly composed of silica) as aggregate, phosphogypsum aggregate used in phosphogypsum filling technology is mainly The ingredient is calcium sulfate dihydrate, which contains a large amount of residual acid and harmful impurities such as phosphorus and fluorine. Studies have shown that the gelling hydration reaction system of conventional gelling materials such as cement and alkali-activated gelling agents requires pH ≥ 11.5, while the pH of phosphogypsum is only 1-5, which contains a large amount of residual acid, which will reduce the hyd...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B18/04C04B20/02C04B28/00
CPCC04B18/0445C04B20/023C04B28/00C04B2111/00724Y02W30/91
Inventor 石英闵晨笛周亚楠李夕兵周诗彤冯娟
Owner CENT SOUTH UNIV
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