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Decoloring and purifying method for flue gas desulfurization gypsum

A desulfurization gypsum and decolorization technology, applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems of secondary pollution and economic burden, and achieve the effect of large production capacity

Active Publication Date: 2015-04-01
HEBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So as to solve the problem of secondary pollution and economic burden caused by the accumulation of a large amount of desulfurized gypsum

Method used

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  • Decoloring and purifying method for flue gas desulfurization gypsum
  • Decoloring and purifying method for flue gas desulfurization gypsum
  • Decoloring and purifying method for flue gas desulfurization gypsum

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Embodiment 1: the specific operations are as follows

[0031] (1) Raw material washing:

[0032] a. Weigh 100.0g of desulfurized gypsum (see attached figure 2 ) and 1000.0ml of water are placed in a beaker with a capacity of 1L. Stir for 30 minutes to fully mix the solid and liquid; then let it stand for 1 minute to make it layered into the upper suspension and the lower solid, and the lower solid is impurities. attached by figure 2 The XRD characterization chart of the desulfurized gypsum raw material shows that the impurity contained in the raw material is CaCO 3 , SiO 2 ; The main component of desulfurization gypsum is CaSO 4 2H 2 O.

[0033] b. Pour the upper suspension liquid layered in a into a 150mm×200mm×30mm (depth: 30mm) disc-shaped container, and discard the lower solid. The suspension in the dish container was allowed to stand for 3 minutes to make it stratified into suspension (upper layer) and solid (lower layer).

[0034] c. The suspension afte...

Embodiment 2

[0044] (1) Washing of raw materials: the operation method is the same as step (1) in Example 1.

[0045] (2) Crystal conversion:

[0046] a. According to water: concentrated hydrochloric acid (12mol / L): CaCl 2 : Middle layer gypsum (on a dry basis, the quality after removing free water) = 100.0ml: 8.0ml: 1.0g: 10.0g to prepare the reaction slurry, then move the slurry into a round bottom flask, and heat the slurry to 100 ℃ reaction 285min.

[0047] b. Transfer the slurry obtained in a. into a beaker and place the beaker at 25° C. for 8 hours at a constant temperature.

[0048] c. Take out the beaker and the slurry in b and stir the slurry gently, then let it stand until the slurry is separated into two phases of solid (lower layer) and suspension, then pour out the suspension; filter out the suspension in the suspension substances (impurities) to obtain a solution, which is then mixed with the solid phase to form a slurry.

[0049] d. Repeat operation c 6 times to wash awa...

Embodiment 3

[0053] (1) Washing of raw materials: the operation method is the same as step (1) in Example 1.

[0054] (2) Crystal conversion:

[0055] a. According to water: concentrated hydrochloric acid (12mol / L): CaCl 2 : Middle layer gypsum (on a dry basis, the quality after removing free water) = 100.0ml: 8.0ml: 1.0g: 10.0g to prepare the reaction slurry, then move the slurry into a round bottom flask, and heat the slurry to 100 ℃ reaction 285min.

[0056] b. Transfer the slurry obtained in a. into a beaker and place the beaker at 40° C. for 8 hours at a constant temperature.

[0057] c. Take out the beaker and the slurry in b and stir the slurry gently, then let it stand until the slurry is separated into two phases of solid (lower layer) and suspension, then pour out the suspension; filter out the suspension in the suspension substances (impurities) to obtain a solution, which is then mixed with the solid phase to form a slurry.

[0058] d. Repeat operation c 6 times to wash awa...

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Abstract

The invention discloses a decoloring and purifying method for flue gas desulfurization gypsum. The decoloring and purifying method is realized through four steps of raw material washing, crystal form converting, product washing and drying, and mother liquor recycling. By virtue of the characteristics of CaSO4.2H2O capable of being converted to CaSO4.0.5H2O with fine particles at 100 DEG C and converted to CaSO4.2H2O with large particles at the normal temperature, the original CaSO4.2H2O crystals are damaged so as to expose out and separate impurities in the crystals through a common physical method. After the colored impurities are separated, the purpose of decoloring and purifying the flue gas desulfurization gypsum can be achieved, so that the problems of secondary pollution and economic burden caused by accumulation of a large quantity of flue gas desulfurization gypsum are solved.

Description

technical field [0001] The invention relates to a method for decolorizing desulfurized gypsum in normal pressure salt solution to obtain gypsum with higher whiteness. technical background [0002] Because my country's coal resources are relatively rich and oil and natural gas resources are relatively scarce, coal has become my country's main energy source. The sulfur content in coal is high, and a large amount of sulfur dioxide is produced during the combustion process. Due to the importance of environmental protection, more than 80% of coal-fired power plants in my country use wet desulfurization devices to desulfurize flue gas. Wet flue gas desulfurization technology produces a large amount of desulfurization by-products, namely desulfurization gypsum. my country's annual output of industrial by-product desulfurization gypsum is about 43 million tons, and the comprehensive utilization rate is about 50%. The accumulation of large amounts of desulfurized gypsum not only oc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F11/46
Inventor 赵斌张伟卓曹吉林陈学青张广林
Owner HEBEI UNIV OF TECH