Method for removing calcium ions and manganese ions in sewage

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a method for removing calcium ions and manganese ions in sewage. The method for removing the calcium ions and the manganese ions in the sewage comprises the following steps: sequentially adding a seed crystal and a sodium carbonate agent into the sewage, mixing, crystallizing and precipitating. The method has the beneficial effects that the seed crystal and the sodium carbonate agent are added into the sewage, so that the concentration of carbonate in the sewage is saturated, carbonate ions, manganese ions and calcium ions in the sewage can form calcium manganese carbonate crystals on the surface of the seed crystal and then precipitate; further, the effect of removing calcium ions and manganese ions in the sewage is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment, and particularly relates to a method for removing calcium ions and manganese ions in sewage. BACKGROUND

[0002] Manganese is an important metal element and an important raw material in the metallurgical industry. Manganese exists in various forms in water, such as divalent manganese ions and manganese dioxide. When the concentration of manganese in water reaches a certain level, the water body becomes turbid, changes color, and produces an odor, affecting water quality. High concentrations of manganese can pollute surface water and groundwater, affecting the survival of aquatic organisms. In addition, manganese can also affect soil quality, causing poisoning in plants and animals. If people drink water with too high a manganese content for a long time, it may lead to manganese poisoning and affect the nervous system.

[0003] The existing methods for removing manganese in sewage mainly include lime method, oxidation-reduction method, flocculation and sedimentation method, micro-electrolysis method, and liquid membrane separation method. The lime method is simple to operate, but it needs to adjust the pH value and may produce a large amount of sludge; the oxidation-reduction method has good manganese removal effect, but it needs to use chemical oxidants and has high cost; the flocculation and sedimentation method is simple to operate and has low cost, but it is strict with the pH value and the flocculant may cause secondary pollution; the micro-electrolysis method needs complex technology and equipment and has high investment cost; the liquid membrane separation method has the characteristics of high efficiency and energy saving, but has high treatment cost. SUMMARY

[0004] The application provides a method for removing calcium ions and manganese ions in sewage, aiming to solve the problems of high cost and secondary pollution caused by the removal of manganese ions in existing sewage.

[0005] The application provides a method for removing calcium ions and manganese ions in sewage, which comprises the following steps: sequentially adding seed crystals and sodium carbonate medicaments into sewage and mixing, and crystallizing and precipitating.

[0006] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the application, the content of calcium ions in the sewage is 300-1200 mg / L, and the content of manganese ions in the sewage is 200-1000 mg / L.

[0007] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the application, the mass ratio of calcium elements to manganese elements in the sewage is (0.9-1):(0.9-1).

[0008] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the application, the pH of the sewage is 8-10.

[0009] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the present application, the seed crystal comprises calcite and / or garnet.

[0010] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the present application, the seed crystal is garnet.

[0011] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the present application, the particle size of the seed crystal is 0.05-0.2mm.

[0012] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the present application, the amount of the seed crystal added is 50-300mg / L.

[0013] According to some embodiments of the method for removing calcium ions and manganese ions in sewage according to the present application, the temperature of the mixing is 20-30℃, and the time of the mixing is 20-30min.

[0014] The beneficial effects of the present application include that the method according to the present application can achieve the effect of removing calcium ions and manganese ions in sewage by adding seed crystal and sodium carbonate reagent into sewage, so that the concentration of carbonate in sewage reaches saturation, and the carbonate ions, manganese ions and calcium ions in sewage will form calcium manganese carbonate crystals on the surface of the seed crystal and then precipitate, thereby achieving the effect of removing calcium ions and manganese ions in sewage. DETAILED DESCRIPTION

[0015] The embodiments of the present application are described in detail below, and the examples of the embodiments are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0016] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0017] The embodiments of the present application provide a method for removing calcium ions and manganese ions in sewage, comprising the following steps: sequentially adding seed crystal and sodium carbonate reagent into sewage for mixing and crystallization precipitation.

[0018] In some embodiments of the present application, the content of calcium ions in the sewage is 300-1200 mg / L, such as 300 mg / L, 500 mg / L, 800 mg / L, 900 mg / L, 1000 mg / L, 1200 mg / L, etc., and the content of manganese ions in the sewage is 200-1000 mg / L, such as 200 mg / L, 500 mg / L, 600 mg / L, 800 mg / L, 1000 mg / L, etc.

[0019] In some embodiments of the present application, the mass ratio of calcium and manganese in the sewage is (0.9-1):(0.9-1), such as 0.9:1, 1:1, 1:0.9, etc. The mass ratio of calcium and manganese close to 1:1 can promote the removal rate of calcium ions and manganese ions to be the highest.

[0020] In some embodiments of the present application, the pH of the sewage is 8-10.

[0021] In some embodiments of the present application, the seed crystal includes calcite and / or garnet.

[0022] In some embodiments of the present application, the seed crystal is garnet.

[0023] In some embodiments of the present application, the particle size of the seed crystal is 0.05-0.2 mm, such as 0.05 mm, 0.08 mm, 0.1 mm, 0.15 mm, 0.2 mm, etc.

[0024] In some embodiments of the present application, the addition amount of the seed crystal is 50-300 mg / L, such as 50 mg / L, 60 mg / L, 80 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, 220 mg / L, 260 mg / L, 300 mg / L, etc. The addition amount of the seed crystal is controlled in the range, which can make the seed crystal crystallization reach the best state.

[0025] In some embodiments of the present application, the temperature of the mixing is 20-30℃, such as 20℃, 25℃, 28℃, 30℃, etc., and the time of the mixing is 20-30 min, such as 20 min, 25 min, 28 min, 30 min, etc.

[0026] The technical solutions of the present application are further described below in combination with specific embodiments.

[0027] Embodiment 1

[0028] A method for removing calcium ions and manganese ions in sewage includes the following steps:

[0029] Detect the content of calcium ions and manganese ions in the sewage. If the mass ratio of calcium and manganese in the sewage is close to 1:1, the method described in this application can be used to remove calcium and manganese ions in the sewage;

[0030] It was detected that the calcium ion content in the sewage to be purified was 500 mg / L and the manganese ion content was 550 mg / L, that is, the mass ratio of calcium ions to manganese ions in the sewage was 1:1.1. The method described in this application can be used to remove calcium ions and manganese ions in the sewage.

[0031] Add garnet with a particle size of 0.05 mm to sewage with a pH of 8, and control the amount of garnet added to 200 mg / L. Then add sodium carbonate reagent to the sewage, then mix and stir at 20°C for 30 minutes, and let it stand for precipitation.

[0032] Example 2

[0033] The method for removing calcium ions and manganese ions from sewage described in Example 2 is different from that in Example 1 only in that the seed crystals added during the implementation of the method for removing calcium ions and manganese ions from sewage described in Example 2 are calcite.

[0034] The specific steps include:

[0035] Detect the content of calcium ions and manganese ions in the sewage. If the mass ratio of calcium and manganese in the sewage is close to 1:1, the method described in this application can be used to remove calcium and manganese ions in the sewage;

[0036] It was detected that the calcium ion content in the sewage to be purified was 500 mg / L and the manganese ion content was 550 mg / L, that is, the mass ratio of calcium ions to manganese ions in the sewage was 1:1.1. The method described in this application can be used to remove calcium ions and manganese ions in the sewage.

[0037] Add calcite with a particle size of 0.05 mm to sewage with a pH of 8, and control the amount of calcite added to 200 mg / L. Then add sodium carbonate reagent to the sewage, then mix and stir at 20°C for 30 minutes, and let it stand for precipitation.

[0038] Example 3

[0039] The method for removing calcium ions and manganese ions from sewage described in Example 3 is different from that in Example 1 only in that the amount of seed crystal added during the implementation of the method for removing calcium ions and manganese ions from sewage described in Example 3 is 50 mg / L.

[0040] The specific steps include:

[0041] Detect the content of calcium ions and manganese ions in the sewage. If the mass ratio of calcium and manganese in the sewage is close to 1:1, the method described in this application can be used to remove calcium and manganese ions in the sewage;

[0042] It was detected that the calcium ion content in the sewage to be purified was 500 mg / L and the manganese ion content was 550 mg / L, that is, the mass ratio of calcium ions to manganese ions in the sewage was 1:1.1. The method described in this application can be used to remove calcium ions and manganese ions in the sewage.

[0043] Add garnet with a particle size of 0.05 mm to sewage with a pH of 8, and control the amount of garnet added to 50 mg / L. Then add sodium carbonate reagent to the sewage, then mix and stir at 20°C for 30 minutes, and let it stand for precipitation.

[0044] Example 4

[0045] The method for removing calcium ions and manganese ions from sewage described in Example 4 is different from that in Example 1 only in that the amount of seed crystal added during the implementation of the method for removing calcium ions and manganese ions from sewage described in Example 4 is 100 mg / L.

[0046] The specific steps include:

[0047] Detect the content of calcium ions and manganese ions in the sewage. If the mass ratio of calcium and manganese in the sewage is close to 1:1, the method described in this application can be used to remove calcium and manganese ions in the sewage;

[0048] It was detected that the calcium ion content in the sewage to be purified was 500 mg / L and the manganese ion content was 550 mg / L, that is, the mass ratio of calcium ions to manganese ions in the sewage was 1:1.1. The method described in this application can be used to remove calcium ions and manganese ions in the sewage.

[0049] Add garnet with a particle size of 0.05 mm to sewage with a pH of 8, and control the amount of garnet added to 100 mg / L. Then add sodium carbonate reagent to the sewage, then mix and stir at 20°C for 30 minutes, and let it stand for precipitation.

[0050] Example 5

[0051] The method for removing calcium ions and manganese ions from sewage described in Example 5 is different from that in Example 1 only in that the amount of seed crystal added during the implementation of the method for removing calcium ions and manganese ions from sewage described in Example 5 is 300 mg / L.

[0052] The specific steps include:

[0053] Detect the content of calcium ions and manganese ions in the sewage. If the mass ratio of calcium and manganese in the sewage is close to 1:1, the method described in this application can be used to remove calcium and manganese ions in the sewage;

[0054] It was detected that the calcium ion content in the sewage to be purified was 500 mg / L and the manganese ion content was 550 mg / L, that is, the mass ratio of calcium ions to manganese ions in the sewage was 1:1.1. The method described in this application can be used to remove calcium ions and manganese ions in the sewage.

[0055] Add garnet with a particle size of 0.05 mm to sewage with a pH of 8, and control the amount of garnet added to 300 mg / L. Then add sodium carbonate reagent to the sewage, then mix and stir at 20°C for 30 minutes, and let it stand for precipitation.

[0056] The results of the method for removing calcium ions and manganese ions from wastewater described in Examples 1-5 of the present application are shown in Table 1.

[0057] Table 1

[0058]

[0059]

[0060] As can be seen from Table 1, the method for removing calcium and manganese ions from wastewater described in this application is very effective in removing manganese ions from wastewater. Furthermore, when the amount of seed crystals added is between 100 mg / L and 200 mg / L, the wastewater treatment effect is relatively good; at this point, the pollutants are mostly discharged in the form of crystalline particles. If a relatively small amount of seed crystals is added (Example 3), a large amount of sludge will be generated, which is not conducive to cleaning and the water content of the pollutants is relatively high. If a relatively large amount of seed crystals is added (Example 5), the degree of crystallization of each seed crystal will be unsaturated, resulting in a waste of seed crystals.

[0061] It can also be seen from Table 1 that the selection of seed crystal type is a key factor affecting the effect of the method described in this application, and the effect of selecting garnet as the seed crystal is better than that of calcite as the seed crystal.

[0062] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A method for removing calcium ions and manganese ions from sewage, characterized in that: The following steps are involved: Add seed crystals and sodium carbonate reagent to the sewage in sequence and mix them to form crystals and precipitate.

2. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The content of calcium ions in the sewage is 300-1200 mg / L, and the content of manganese ions in the sewage is 200-1000 mg / L.

3. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The mass ratio of calcium element to manganese element in the sewage is (0.9-1): (0.9-1).

4. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The pH of the sewage is 8-10.

5. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The seed crystals include calcite and / or garnet.

6. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The seed crystal is garnet.

7. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The particle size of the seed crystal is 0.05-0.2 mm.

8. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The amount of the seed crystal added is 50-300 mg / L.

9. The method for removing calcium ions and manganese ions from sewage according to claim 1, wherein: The mixing temperature is 20-30° C., and the mixing time is 20-30 min.

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