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Method and device for preparing building gypsum by phosphogypsum

A technology of building gypsum and phosphogypsum, which is applied in the field of preparing building gypsum, can solve the problems of human living environment hazards, soil air pollution, and low comprehensive utilization rate, and achieve the goals of avoiding natural stacking and aging, reducing environmental pollution, and shortening the production cycle Effect

Active Publication Date: 2017-12-26
HUBEI THREE GORGES POLYTECHNIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the annual discharge of phosphogypsum in my country is 50 million tons, which is basically treated by stockpiling. At present, the cumulative stockpiling exceeds 200 million tons, and the comprehensive utilization rate is less than 10%. At present, most of the phosphogypsum is stacked in the open air, occupying a large area of ​​land. and soluble P 2 o 5 and F ˉ Waiting for leaching with rainwater, producing acidic wastewater, causing serious pollution of soil, water system, and atmosphere, and causing harm to the living environment of human beings

Method used

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  • Method and device for preparing building gypsum by phosphogypsum
  • Method and device for preparing building gypsum by phosphogypsum
  • Method and device for preparing building gypsum by phosphogypsum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The phosphogypsum slurry obtained from a chemical plant in Xiaoting, Yichang, Hubei, after pressure filtration, the pH value of the sample is 2.36, and the composition analysis results are shown in Table 1 (in wt%):

[0026] P 2 o 5

F -

CaO

SO 3

SiO 2

K 2 o

Na 2 o

Al 2 o 3

Fe 2 o 3

Cl -

loss

crystal water

total

0.41

0.04

28.9

41.3

6.65

0.17

0.06

0.44

0.03

0.003

2.67

19.1

99.71

[0027] Table 1

[0028] The sample and quicklime were mixed and stirred evenly at a ratio of 99.2:0.8, put into the retting warehouse for retting at 38°C for 30 hours, and the pH value was continuously sampled and analyzed to be 5.88, then sent to the calciner for calcination, and the flue gas temperature 720°C, outlet flue gas temperature 135°C, calcination time 30min, then send the material into the homogenizing cooling silo, and leave it for 24h to obtain a q...

Embodiment 2

[0032] Mix and stir the same sample and quicklime in the ratio of 99:1 evenly in Example 1, put it into the retting warehouse for retting for 45 hours at 38°C, continuously sample and analyze the pH value to be 6.79, send it to the calciner for calcination, and The furnace flue gas temperature is 730°C, the outlet flue gas temperature is 135°C, and the calcination time is 45 minutes. Finally, the material is sent to the homogenizing cooling silo, and the qualified product is obtained after standing for 24 hours. The performance analysis results of the finished product are shown in Table 3:

[0033]

[0034]

[0035] table 3

Embodiment 3

[0037] The phosphogypsum slurry was taken from a chemical plant in Yidu, Yichang, Hubei. After pressure filtration, the pH value of the sample was 2.58. The composition analysis results are shown in Table 4, and the unit is wt%.

[0038] P 2 o 5

F -

CaO

SO 3

SiO 2

K 2 o

Na 2 o

al 2 o 3

Fe 2 o 3

Cl -

loss

crystal water

total

0.44

0.03

29.12

39.9

6.89

0.15

0.05

0.52

0.04

0.002

2.43

20.31

99.84

[0039] Table 4

[0040] The sample and quicklime were mixed and stirred evenly at a ratio of 98.5:1.5, put into the retting warehouse for retting at 40°C for 50 hours, and the pH value was continuously sampled and analyzed to be 7.84, and sent to the calciner for calcination. 720°C, outlet flue gas temperature 135°C, calcination time 45min, then send the material into the homogenizing cooling silo, and leave it for 24h to obtain a qualified product. The...

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Abstract

The invention discloses a method and device for preparing building gypsum by phosphogypsum. The method concretely comprises the steps of (1) filtering slag slurry generated by a phosphoric acid production device; obtaining filter cake which is phosphogypsum; controlling the water content to be less than or equal to 25 weight percent; then, uniformly mixing the phosphogypsum and quick lime according to a mass ratio of (90 to 99.5):(0.5 to 10); performing homogenizing retting for 24 to 72h; (2) feeding the materials subjected to retting into a roasting kiln to be roasted; performing down-flow direct contact with the high-temperature smoke gas in the kiln; ensuring the content of hemihydrate gypsum in discharged materials not to be lower than 60 weight percent; performing homogenizing cooling on the discharged materials; obtaining the building gypsum. A filter press is arranged beside a slag slurry pool for slag slurry generated by the phosphoric acid production device; the filter cake subjected to filter press is phosphogypsum raw materials; the phosphogypsum can be directly mixed and processed with the quicklime to prepare the building gypsum; the long-time outdoor piling aging treatment on the slag slurry can be avoided; the environment pollution is reduced.

Description

technical field [0001] The invention belongs to the field of phosphorus chemical production, and in particular relates to a method and a device for preparing building gypsum from solid waste phosphogypsum produced in the phosphoric acid production process as a raw material. Background technique [0002] Phosphogypsum is the most important industrial by-product in the production of phosphorus chemical industry in my country, and it is the precipitate mainly composed of calcium sulfate dihydrate discharged from the production process of phosphate fertilizer enterprises. Every ton of P produced 2 o 5 It is necessary to discharge 4.5-5.5 tons of phosphogypsum, the color is gray or yellowish, the pH value is between 2 and 4, and the chemical composition is relatively complex. [0003] At present, the annual discharge of phosphogypsum in my country is 50 million tons, which is basically treated by stockpiling. At present, the cumulative stockpiling exceeds 200 million tons, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B11/036C04B11/024
CPCC04B11/024C04B11/0285Y02W30/91
Inventor 古永红张战利
Owner HUBEI THREE GORGES POLYTECHNIC
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