Method for preparing high-purity calcium carbonate from high-calcium fly ash by using recyclable amino acid extracting agent

A high-calcium fly ash, amino acid technology, applied in the direction of calcium carbonate/strontium/barium, etc., can solve the problems of increasing the cost of the indirect method and the rapid decay of the cycle performance, and achieve the improvement of the reaction rate and conversion rate, high efficiency and selectivity. Effects of leaching, strong pH buffering properties

Pending Publication Date: 2022-07-05
HUAZHONG AGRI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Because strong acid extractants such as hydrochloric acid, sulfuric acid, and nitric acid cannot be regenerated, weak acid extractants such as ammonium chloride, ammonium nitrate, ammonium sulfate, ammonium bisulfate, and ammonium acetate cannot be completely regenerated or the cycle performance decays too quickly after regeneration
Therefore, the extensive use of pH regulators such as leaching agents and ammonia increases the process cost of the indirect method

Method used

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  • Method for preparing high-purity calcium carbonate from high-calcium fly ash by using recyclable amino acid extracting agent
  • Method for preparing high-purity calcium carbonate from high-calcium fly ash by using recyclable amino acid extracting agent
  • Method for preparing high-purity calcium carbonate from high-calcium fly ash by using recyclable amino acid extracting agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1) Add high calcium fly ash with a solid-liquid ratio of 150g / L, 200g / L and 300g / L into 2mol / L glycine to prepare a mixed slurry. The stirring speed is 200rpm, and the extraction process is performed for 1 hour to prepare calcium source leaching. slurry;

[0026] 2) Perform solid-liquid separation on the leaching slurry, take the leaching solution and introduce CO 2 15% CO by volume 2 / N 2 Mixed gas as simulated flue gas for CO 2 mineralization;

[0027] 3) After 1 hour of reaction, stop gas supply, carry out solid-liquid separation on the mineralized slurry, recycle the filtrate as a leaching agent, and dry the solid to obtain a high-purity calcium carbonate product.

[0028] 4) Take 30 parts of standard cement, 20 parts of fly ash slag, 25 parts of quartz sand, and 20 parts of water, and stir to obtain a mixture. Under the conditions of humidity of 95% and temperature of 20° C., and curing for 28 days, fly ash concrete can be obtained.

[0029] like figure 2 S...

Embodiment 2

[0031] 0.25mol / L, 0.5mol / L, 1mol / L, 2mol / L glycine solution was used as the leaching agent, the solid-liquid ratio was 200g / L, and other parameters, conditions and implementation steps were consistent with those in Example 1, as shown in Figure 3 Shown is the calcium carbonate yield of 200g / L fly ash in different glycine concentrations, such as Figure 4 Shown is the calcium carbonate morphology of 200 g / L fly ash in 2 mol / L glycine.

[0032] Depend on Figure 2-4 It is known that:

[0033] 1. When the solid-liquid ratio is 150-300g / L, the calcium carbonate yield is all >75kg / t, and when the solid-liquid ratio is 200g / L, the highest yield is 107kg / t.

[0034] 2. As the concentration of glycine increases, the yield of calcium carbonate increases.

[0035] 3. When 200g / L fly ash is added to 2mol / L glycine, the obtained calcium carbonate is a typical spherical vaterite.

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Abstract

The invention relates to a method for preparing high-purity calcium carbonate from high-calcium fly ash by using a recyclable amino acid extracting agent, which comprises the following steps: step 1, extracting the high-calcium fly ash by using an amino acid solution, and filtering to obtain an extracting solution and calcium-poor fly ash, the calcium-poor fly ash can be used for preparing concrete; step 2, introducing CO2-containing flue gas into the leaching solution and stirring, selectively absorbing CO2 by the leaching solution, converting the absorbed CO2 into carbonate and hydrogen ions, reacting the carbonate with calcium amino acid in the leaching solution to generate high-purity calcium carbonate and deprotonated amino acid, combining the deprotonated amino acid with the hydrogen ions to regenerate an amino acid solution, and removing the hydrogen ions to obtain the high-purity calcium carbonate and the deprotonated amino acid. After filtration, a high-purity calcium carbonate product and a regenerated amino acid solution are obtained, and the solution can be used for coal ash extraction in the next cycle, so that cyclic utilization is realized. According to the invention, high-value utilization of the high-calcium fly ash is realized, and emission reduction and utilization of CO2 in a power plant are promoted at the same time.

Description

technical field [0001] The invention belongs to solid waste resource utilization, CO 2 The technical field of capture and utilization, and chemical materials, specifically relates to a method for preparing high-purity calcium carbonate from high-calcium fly ash by using a recyclable amino acid solution. Background technique [0002] Fly ash is a by-product of coal combustion for power generation. The annual output of fly ash in my country is about 620 million tons, accounting for more than 50% of the global output. As a high-alkali solid waste, improper disposal of fly ash will cause serious environmental hazards such as soil and water pollution and ecological cycle damage. The traditional disposal method of fly ash is landfill treatment, which is simple and easy to implement, but it is harmless, resourceful, and has a low degree of reduction. It occupies a large area and is likely to cause secondary pollution. The traditional utilization of fly ash is mainly used in cemen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18C04B18/08C04B28/00C04B20/02
CPCC01F11/18C04B18/08C04B28/00C04B20/023C01P2004/32C01P2006/80C01P2004/01C04B14/06C04B22/002
Inventor 纪龙郑璇晏水平贺清尧
Owner HUAZHONG AGRI UNIV
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