A method for adsorbing impurities in ammonium sulfate mother liquor by using coconut shell activated carbon activated by nitric acid

Abstract

This invention discloses a method for adsorbing impurities from ammonium sulfate mother liquor using coconut shell activated carbon activated with nitric acid. The method involves placing a 20-40 mesh coconut shell activated carbon sample in deionized water and hydrothermally treating it in a water bath at 60-80°C for 2-3 hours. After drying, it is refluxed with 4 mol / L nitric acid at 60-80°C for 2-3 hours, then slowly filtered and washed 7-8 times with neutral filter paper, and dried at 50°C for 10-12 hours to obtain nitric acid-activated coconut shell activated carbon. The ammonium sulfate mother liquor is heated to 60-75°C and thoroughly mixed. The nitric acid-activated coconut shell activated carbon is added, and the mixture is stirred at 50-60°C at a stirring speed of 200-300 r / min for 90-120 minutes. After stirring, the solid and liquid are separated using a 20 mesh filter, and the mixture is cooled for crystallization. This invention addresses the problem of poor ammonium sulfate crystallization in the ammonium sulfate mother liquor obtained from ammonia desulfurization. It utilizes coconut shell activated carbon activated with nitric acid to adsorb impurities in the ammonium sulfate mother liquor. This method is simple and easy to operate, effectively removing factors that interfere with ammonium sulfate crystallization and improving the amount and quality of ammonium sulfate crystals. It provides a theoretical basis for optimizing ammonium sulfate crystallization in ammonia desulfurization.

Description

Technical Field

[0001] This invention belongs to the technical field, specifically relating to a method for adsorbing impurities in ammonium sulfate mother liquor by activating coconut shell activated carbon with nitric acid. Background Technology

[0002] Ammonia desulfurization is an important technology for removing SO2 from sintering flue gas in steel enterprises. Its desulfurization efficiency is as high as 95% or more, with a good desulfurization effect and no secondary pollution. Its by-product ammonium sulfate also has good economic value. However, due to the large number of impurities carried by the sintering flue gas, such as insoluble mechanical impurities, soluble mechanical impurities, organic matter, and oily substances, and the fact that these impurities are easily enriched in the ammonium sulfate mother liquor, the system is prone to frequent blockage and severe corrosion of equipment. This leads to problems such as small and uneven ammonium sulfate crystal size and periodic non-discharge during the ammonium sulfate crystallization process, which affects the stability of the system and increases the energy consumption of operation. (2) The amount of ammonium sulfate crystallization is small. (3) The oxidation rate of ammonium sulfite is low and the amount of ammonia water used is too large. (4) The quality of ammonium sulfate products is poor and contains some impurities.

[0003] The present invention aims to provide a method for adsorbing impurities in ammonium sulfate mother liquor by activating coconut shell activated carbon with nitric acid. Summary of the Invention

[0004] The purpose of this invention is to provide a method for adsorbing impurities in ammonium sulfate mother liquor using coconut shell activated carbon activated with nitric acid.

[0005] The objective of this invention is achieved by using nitric acid-activated coconut shell activated carbon to adsorb impurities from ammonium sulfate mother liquor, which is implemented through the following steps:

[0006] 1) Place the 20-40 mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a water bath at 60-80 ℃ for 2-3 hours. After drying, reflux it with 4 mol / L nitric acid at 60-80 ℃ for 2-3 hours. Then, slowly filter and wash it with neutral filter paper 7-8 times and dry it at 50 ℃ for 10-12 hours to obtain coconut shell activated carbon activated by nitric acid.

[0007] 2) Heat 100 mL of ammonium sulfate mother liquor to 60~75℃ and mix thoroughly. Add coconut shell activated carbon activated by nitric acid. Stir at 50-60℃ and a stirring speed of 200-300 r / min for 90-120 min. After stirring, use a 20 mesh filter to separate the solid and liquid and then cool to crystallize.

[0008] The beneficial effects of this invention are as follows: This invention addresses the problem of poor ammonium sulfate crystallization in the ammonium sulfate mother liquor obtained by ammonia desulfurization. It uses coconut shell activated carbon activated by nitric acid to adsorb impurities in the ammonium sulfate mother liquor. This method is simple and easy to operate, and can effectively remove factors that interfere with ammonium sulfate crystallization, thereby improving the amount and quality of ammonium sulfate crystals. This provides a theoretical basis for optimizing ammonium sulfate crystallization in ammonia desulfurization. Attached Figure Description

[0009] Figure 1 The image shows the XRD pattern of ammonium sulfate crystals prepared in Example 1. The pure sample is pure ammonium sulfate, the factory sample is ammonium sulfate produced by a certain company, and the experimental sample is ammonium sulfate crystallized from ammonium sulfate mother liquor without adsorption by coconut shell activated carbon. Detailed Implementation

[0010] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0011] This invention discloses a method for adsorbing impurities in ammonium sulfate mother liquor using coconut shell activated carbon activated with nitric acid, which is implemented according to the following steps:

[0012] 1) Place the 20-40 mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a water bath at 60-80 ℃ for 2-3 hours. After drying, reflux it with 4 mol / L nitric acid at 60-80 ℃ for 2-3 hours. Then, slowly filter and wash it with neutral filter paper 7-8 times and dry it at 50 ℃ for 10-12 hours to obtain coconut shell activated carbon activated by nitric acid.

[0013] 2) Heat 100 mL of ammonium sulfate mother liquor to 60~75℃ and mix thoroughly. Add coconut shell activated carbon activated by nitric acid. Stir at 50-60℃ and a stirring speed of 200-300 r / min for 90-120 min. After stirring, use a 20 mesh filter to separate the solid and liquid and then cool to crystallize.

[0014] The mass-to-volume ratio of coconut shell activated carbon to nitric acid is 2:2-3 g / mL.

[0015] The mass-to-volume ratio of coconut shell activated carbon after nitric acid activation to ammonium sulfate mother liquor is 0.1-0.6 g / 100 mL.

[0016] Example 1

[0017] 1) Place 20 g of 40-mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in an 80 ℃ water bath for 2 h. After drying, reflux the activated carbon with 30 mL of 4 mol / L nitric acid at 80 ℃ for 2 h. Then, slowly filter and wash it 8 times with neutral filter paper and dry it at 50 ℃ for 12 h to obtain coconut shell activated carbon activated by nitric acid.

[0018] 2) Heat 100 mL of ammonium sulfate mother liquor obtained from ammonia desulfurization to 60℃ and mix thoroughly. Add 0.2 g of coconut shell activated carbon activated with nitric acid, and stir for 100 min at 60℃ and 250 r / min. After stirring, separate the solid and liquid phases using a 20-mesh filter, cool, and crystallize. The XRD pattern of the obtained ammonium sulfate crystals is shown below. Figure 1 As shown.

[0019] Example 2

[0020] 1) Place 20 g of 40-mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it for 3 h in a 60 ℃ water bath. After drying, reflux the activated carbon with 20 mL of 4 mol / L nitric acid at 60 ℃ for 3 h. Then, slowly filter and wash it 8 times with neutral filter paper and dry it at 50 ℃ for 10 h to obtain coconut shell activated carbon activated by nitric acid.

[0021] 2) Heat 100 mL of ammonium sulfate mother liquor obtained from ammonia desulfurization to 70℃ and mix thoroughly. Add 0.1 g of coconut shell activated carbon activated with nitric acid and stir for 90 min at 60℃ and 300 r / min. After stirring, separate the solid and liquid using a 20-mesh filter and cool to crystallize to obtain ammonium sulfate crystals.

[0022] Example 3

[0023] 1) Place 20 g of 20-mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a 70 ℃ water bath for 2 h. After drying, reflux the activated carbon with 30 mL of 4 mol / L nitric acid at 70 ℃ for 2.5 h. Then, slowly filter and wash it 9 times with neutral filter paper and dry it at 50 ℃ for 12 h to obtain coconut shell activated carbon activated by nitric acid.

[0024] 2) Heat 100 mL of ammonium sulfate mother liquor obtained from ammonia desulfurization to 75℃ and mix thoroughly. Add 0.3 g of coconut shell activated carbon activated with nitric acid and stir for 120 min at 50℃ and 200 r / min. After stirring, separate the solid and liquid using a 20-mesh filter and cool to crystallize to obtain ammonium sulfate crystals.

[0025] Example 4

[0026] 1) Place 20 g of 20-mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a 70 ℃ water bath for 2 h. After drying, reflux the activated carbon with 30 mL of 4 mol / L nitric acid at 70 ℃ for 2.5 h. Then, slowly filter and wash it 9 times with neutral filter paper and dry it at 50 ℃ for 12 h to obtain coconut shell activated carbon activated by nitric acid.

[0027] 2) Heat 100 mL of ammonium sulfate mother liquor to 75℃ and mix thoroughly. Add 0.4 g of coconut shell activated carbon activated with nitric acid and stir for 120 min at 50℃ and 200 r / min. After stirring, separate the solid and liquid through a 20-mesh filter and cool to crystallize to obtain ammonium sulfate crystals.

[0028] Example 5

[0029] 1) Place 20 g of 20-mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a 70 ℃ water bath for 2 h. After drying, reflux the activated carbon with 30 mL of 4 mol / L nitric acid at 70 ℃ for 2.5 h. Then, slowly filter and wash it 9 times with neutral filter paper and dry it at 50 ℃ for 12 h to obtain coconut shell activated carbon activated by nitric acid.

[0030] 2) Heat 100 mL of ammonium sulfate mother liquor obtained from ammonia desulfurization to 75℃ and mix thoroughly. Add 0.5 g of coconut shell activated carbon activated with nitric acid and stir for 120 min at 50℃ and 200 r / min. After stirring, separate the solid and liquid using a 20-mesh filter and cool to crystallize to obtain ammonium sulfate crystals.

[0031] Example 6

[0032] 1) Place 20 g of 20-mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a 60 ℃ water bath for 2 h. After drying, reflux the activated carbon with 30 mL of 4 mol / L nitric acid at 70 ℃ for 2.5 h. Then, slowly filter and wash it 9 times with neutral filter paper and dry it at 50 ℃ for 12 h to obtain coconut shell activated carbon activated by nitric acid.

[0033] 2) Heat 100 mL of ammonium sulfate mother liquor obtained from ammonia desulfurization to 75℃ and mix thoroughly. Add 0.6 g of coconut shell activated carbon activated with nitric acid and stir for 120 min at 55℃ and 250 r / min. After stirring, separate the solid and liquid using a 20-mesh filter and cool to crystallize to obtain ammonium sulfate crystals.

[0034] from Figure 1 It can be seen that the main diffraction peaks of the ammonium sulfate crystals prepared by the method of the present invention are largely consistent with those of the crystals obtained by crystallization of the original ammonium sulfate mother liquor, and the intensity is increased while the impurities are significantly reduced.

Claims

1. A method for adsorbing impurities in ammonium sulfate mother liquor using nitric acid-activated coconut shell activated carbon, characterized in that, Follow these steps to achieve the following: 1) Place the 20-40 mesh coconut shell activated carbon sample in deionized water and hydrothermally treat it in a water bath at 60-80℃ for 2-3 hours. After drying, reflux it with 4mol / L nitric acid at 60-80℃ for 2-3 hours. Then, slowly filter and wash it with neutral filter paper 7-8 times and dry it at 50℃ for 10-12 hours to obtain nitric acid activated carbon. The mass-volume ratio of coconut shell activated carbon to nitric acid is 2:2-3 g / mL. 2) Heat the ammonium sulfate mother liquor to 60~75℃ and mix thoroughly. Add coconut shell activated carbon activated by nitric acid. The mass-volume ratio of the coconut shell activated carbon activated by nitric acid to the ammonium sulfate mother liquor is 0.1~0.6g / 100mL. Stir at 50~60℃ and a stirring speed of 200~300r / min for 90~120min. After stirring, use a 20-mesh filter to separate the solid and liquid, and then cool and crystallize.

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