Antimony removal coagulant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of water treatment, and provides an antimony removal coagulant as well as a preparation method and application thereof. The antimony removal coagulant provided by the invention is prepared from the following raw materials: an aluminum foil pickling solution, calcium aluminate powder, ferric trichloride and an auxiliary agent, wherein the auxiliary agent is inorganic acid. The aluminum foil pickling solution is used for providing aluminum chloride, the aluminum chloride and the calcium aluminate powder can react to generate polyaluminum chloride, and polyaluminum ferric chloride with a good flocculation effect is generated by combining ferric trichloride; meanwhile, inorganic acid is adopted as the auxiliary agent, so that flocculation of the coagulant is more sensitive, the stability of the coagulant can be improved, and the color of the effluent quality is prevented from exceeding the standard. Moreover, the aluminum foil pickling solution is adopted as a raw material, so that waste is treated by waste, the method is environment-friendly, the raw materials are easy to obtain, the cost is low, and the method has wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to an antimony removal coagulant and a preparation method and application thereof. Background Art

[0002] In recent years, the antimony pollution problem in the printing and dyeing industry has attracted widespread attention. Antimony compounds are commonly used catalysts in the production of textile raw materials (PET). They are released into water bodies during the printing and dyeing process, polluting the environment. In addition, antimony is a toxic and carcinogenic heavy metal that is easily absorbed by organisms and is listed in the priority pollutant list by the World Health Organization.

[0003] At present, the main treatment methods for antimony-containing wastewater include adsorption, electrochemical, membrane, coagulation and sedimentation, etc. Among them, adsorption, electrochemical and membrane are all relatively expensive, while coagulation and sedimentation is to remove antimony by adding coagulants to react chemically with the antimony element in the wastewater to form precipitation or floccules. This method is widely used due to its simple process, convenient operation, and economic efficiency.

[0004] Commonly used coagulation and precipitation agents for antimony removal include iron salts, aluminum salts and sulfides. Ferric chloride is a traditional iron salt with strong corrosiveness and poor stability. The treated water tends to show the color of iron, and the color of the effluent water exceeds the standard. Ferrous sulfate has a low antimony removal rate and poor stability. The antimony removal efficiency of sulfides is also low, and antimony sulfide precipitates may be generated during the antimony removal process, causing secondary pollution.

[0005] In summary, there is an urgent need to provide a coagulant with good stability and high antimony removal efficiency. Summary of the invention

[0006] In view of this, the present invention provides an antimony removal coagulant and a preparation method and application thereof. The antimony removal coagulant provided by the present invention has good stability, high antimony removal efficiency, simple preparation method, readily available raw materials and low cost.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] An antimony removal coagulant comprises the following raw materials in weight percentage: 30-55% of aluminum foil pickling solution, 38.5-65% of calcium aluminate powder, 0.1-1.5% of ferric chloride, and 1-5% of an auxiliary agent;

[0009] The components of the aluminum foil pickling solution include hydrochloric acid and aluminum chloride; the aluminum content in the aluminum foil acid is 4-8wt% based on Al2O3;

[0010] The auxiliary agent is an inorganic acid.

[0011] Preferably, the antimony removal coagulant comprises the following raw materials in weight percentage: 35-46% of aluminum foil pickling solution, 50-62% of calcium aluminate powder, 1-1.5% of ferric chloride, and 2-3% of auxiliary agent.

[0012] Preferably, the inorganic acid is sulfuric acid or phosphorous acid; the concentration of the sulfuric acid is 95-98 wt %.

[0013] The present invention also provides a method for preparing the antimony removal coagulant described in the above scheme, comprising the following steps:

[0014] Aluminum foil acid and calcium aluminate powder are mixed to carry out polymerization reaction to obtain a polymerization reaction liquid;

[0015] The polymerization reaction liquid and ferric chloride are mixed to carry out a compounding reaction to obtain a compounded reaction liquid;

[0016] The composite reaction liquid and the auxiliary agent are mixed to obtain the antimony removal coagulant.

[0017] Preferably, the polymerization reaction temperature is 75-88°C.

[0018] Preferably, the polymerization reaction time is 1 to 4 hours.

[0019] Preferably, the temperature of the compounding reaction is 75-88°C.

[0020] Preferably, the compounding reaction time is 0.2 to 1 h.

[0021] Preferably, after the compounding reaction, the obtained reaction liquid is filtered, and the obtained filtrate is the antimony removal coagulant.

[0022] The present invention also provides the use of the antimony removal coagulant described in the above scheme or the antimony removal coagulant prepared by the preparation method described in the above scheme in the treatment of antimony-containing wastewater.

[0023] The present invention provides an antimony removal coagulant, comprising the following raw materials in weight percentage: 30-55% of aluminum foil pickling solution, 38.5-65% of calcium aluminate powder, 1-1.5% of ferric chloride, and 1-5% of an auxiliary agent; the components of the aluminum foil pickling solution include hydrochloric acid and aluminum chloride; the aluminum content in the aluminum foil acid is 4-8wt% in terms of Al2O3; and the auxiliary agent is an inorganic acid. The present invention uses the aluminum foil pickling solution to provide aluminum chloride, and the aluminum chloride and calcium aluminate powder can react to generate polyaluminum chloride, which is then combined with ferric chloride to generate polyaluminum chloride iron with good flocculation effect; at the same time, the present invention uses inorganic acid as an auxiliary agent, which can make the coagulant flocculate more sensitively and can also achieve good flocculation under low temperature and low turbidity conditions; and the auxiliary agent can also improve the stability of the coagulant and avoid the chromaticity of the effluent water quality exceeding the standard. In addition, the present invention uses the aluminum foil pickling solution as a raw material, which can achieve waste treatment with waste, is environmentally friendly, and the raw materials are easy to obtain, the cost is low, and it has a wide range of application prospects.

[0024] The present invention also provides a method for preparing the antimony removal coagulant described in the above scheme. The preparation method provided by the present invention has simple steps, is easy to operate, and is suitable for large-scale production. DETAILED DESCRIPTION

[0025] The invention provides an antimony removal coagulant, which comprises the following raw materials in weight percentage: 30-55% of aluminum foil pickling solution, 38.5-65% of calcium aluminate powder, 0.1-1.5% of ferric chloride, and 1-5% of an auxiliary agent;

[0026] The components of the aluminum foil pickling solution include hydrochloric acid and aluminum chloride; the aluminum content in the aluminum foil acid is 4-8wt% based on Al2O3;

[0027] The auxiliary agent is an inorganic acid.

[0028] Unless otherwise specified, all raw materials / components used in the present invention are commercially available.

[0029] In terms of weight percentage, the raw materials for preparing the antimony removal coagulant include 35-55% of aluminum foil pickling solution, preferably 35-46%, and specifically 35%, 40% or 45%. In the present invention, the components of the aluminum foil pickling solution include hydrochloric acid and aluminum chloride; in terms of Al2O3, the aluminum content in the aluminum foil acid is preferably 4-8wt%, and specifically 4wt%, 5wt%, 6wt%, 7wt% or 8wt%; the aluminum foil pickling solution is specifically aluminum foil bag pickling waste liquid.

[0030] In terms of weight percentage, the raw materials for preparing the antimony removal coagulant include 38.5-65% calcium aluminate powder, preferably 50-62%. In the present invention, the calcium aluminate powder is used to react with aluminum chloride in the aluminum foil pickling solution to generate polyaluminum chloride.

[0031] In terms of weight percentage, the raw materials for preparing the antimony removal coagulant include 0.1-1.5% of ferric chloride, preferably 1-1.5%, specifically 1%, 1.4% or 1.5%.

[0032] In terms of weight percentage, the raw materials for preparing the antimony removal coagulant include 1-5%, preferably 2-3% of an auxiliary agent. In the present invention, the auxiliary agent is an inorganic acid, preferably sulfuric acid or phosphorous acid; the concentration of the sulfuric acid is preferably 95-98wt%. In the present invention, the auxiliary agent can improve the flocculation sensitivity of the coagulant and improve the stability of the coagulant.

[0033] The present invention also provides a method for preparing the antimony removal coagulant described in the above scheme, comprising the following steps:

[0034] Aluminum foil acid and calcium aluminate powder are mixed to carry out polymerization reaction to obtain a polymerization reaction liquid;

[0035] The polymerization reaction liquid and ferric chloride are mixed to carry out a compounding reaction to obtain a compounded reaction liquid;

[0036] The composite reaction liquid and the auxiliary agent are mixed to obtain the antimony removal coagulant.

[0037] The present invention mixes aluminum foil acid and calcium aluminate powder for polymerization reaction to obtain a polymerization reaction liquid. In the present invention, the polymerization reaction temperature is preferably 75 to 88° C., more preferably 83 to 85° C.; the polymerization reaction time is preferably 1 to 4 hours, more preferably 2 to 3.5 hours. In a specific embodiment of the present invention, it is preferred to first put aluminum foil acid into a reactor, stir and heat it to 75 to 88° C., and then slowly add calcium aluminate powder to perform a polymerization reaction. During the polymerization reaction, aluminum chloride and calcium aluminate powder react to form polyaluminum chloride.

[0038] After the polymerization reaction is completed, the present invention mixes the obtained polymerization reaction liquid and ferric chloride for a compound reaction to obtain a compound reaction liquid. In the present invention, the temperature of the compound reaction is preferably 75 to 88°C, more preferably 83 to 85°C; the time of the compound reaction is preferably 0.2 to 1h, more preferably 0.3 to 0.5h; in a specific embodiment of the present invention, after the polymerization reaction is completed, it is preferred to directly add ferric chloride to the reaction liquid and perform a compound reaction under stirring conditions. During the compound reaction, polyaluminum chloride and ferric chloride are compounded to generate polyaluminum ferric chloride.

[0039] In the present invention, after the compounding reaction, it is preferred to further include filtering the obtained reaction solution, and the obtained filtrate is the antimony removal coagulant. In the present invention, the chemical formula of the antimony removal coagulant is: [Al2(OH) n Cl 6-n ] m [Fe2(OH) N Cl6-N ] M , where n, m, N, and M are all integers.

[0040] The present invention also provides the use of the antimony removal coagulant described in the above scheme or the antimony removal coagulant prepared by the preparation method described in the above scheme in the treatment of antimony-containing wastewater. In the present invention, the total antimony content of the antimony-containing wastewater is preferably 0.1-1.5 mg / L, the pH value is preferably 7.5-9, and the turbidity is preferably 1-8 NTU; the amount used in the antimony removal coagulant is 100-300 ppm.

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Example 1

[0043] Add 1.75 tons of aluminum foil acid into the reactor, stir and heat to 85°C, slowly add 3.1 tons of calcium aluminate powder, react for 3 hours, add 0.05 tons of ferric chloride, stir for 0.2 hours, add 0.1 tons of phosphorous acid, mix well, filter, and the filtrate is the finished product of antimony removal coagulant.

[0044] Example 2

[0045] Add 2.25 tons of aluminum foil acid into the reactor, stir and heat to 83°C, slowly add 2.53 tons of calcium aluminate powder, react for 3.5 hours, add 0.07 tons of ferric chloride, stir for 0.5 hours, add 0.15 tons of phosphorous acid, mix well, filter, and the filtrate is the finished product of antimony removal coagulant.

[0046] Test Example 1

[0047] The sewage used in this test example is the influent of a sewage treatment plant in an industrial area, in which the total antimony content of the raw water is 1.12 mg / L, the pH value is 8.14, the turbidity is 6.17, and the chromaticity is 30.

[0048] The coagulant was added to the sewage, rapidly stirred at 250 rpm for 2 min, then slowly stirred at 40 rpm for 20 min, and then precipitated for 20 min, and the supernatant was taken for total antimony content and chromaticity test; wherein the coagulant used was the antimony removal coagulant prepared in Example 1 or Example 2, and ferric chloride and polyferric sulfate were used for control tests, and the addition amount of the coagulant was 100 ppm.

[0049] The test results are shown in Table 1.

[0050] Table 1 Antimony removal effect test results

[0051]

[0052] According to the data in Table 1, it can be seen that the antimony removal efficiency of the antimony removal coagulant prepared by the present invention can reach about 96%, and the chromaticity of the effluent is reduced from 30 to 11-12, indicating that the stability of the coagulant is good. When ferric chloride and polyferric sulfate are used for antimony removal, the antimony removal efficiency is low, and the chromaticity of the effluent is improved after treatment.

[0053] The antimony removal rate of the antimony removal coagulant of the present invention was tested under low temperature and low turbidity conditions. The results showed that when the turbidity of the antimony-containing wastewater was 1-2 NTU and the water temperature was 2-5°C, the turbidity removal rate of the antimony removal coagulant prepared in Examples 1-2 was 70-90%, while the turbidity removal rate of polyaluminium chloride was only 20-30%.

[0054] Comparative Example 1

[0055] 1.75 tons of aluminum foil acid was added to the reactor, stirred and heated to 85°C, 3.1 tons of calcium aluminate powder was slowly added, reacted for 3 hours, 0.05 tons of ferric chloride was added, stirred for 0.2 hours, filtered, and the filtrate was the antimony removal coagulant product A. The antimony removal effect of the finished product A was tested according to the conditions in Test Example 1, and compared with the coagulant prepared in Example 1, and the results are shown in Table 2.

[0056] Table 2 Antimony removal effect test results

[0057]

[0058] According to the data in Table 2, it can be seen that the coagulant in Comparative Example 1 omits the condition of phosphorous acid, and the antimony removal rate of the obtained coagulant decreases, indicating that phosphorous acid can improve the antimony removal rate of the coagulant.

[0059] In addition, the validity period of the coagulants prepared in Examples 1 and 2 and the coagulant prepared in Comparative Example 1 was tested, and the results showed that after the coagulants prepared in Examples 1 and 2 were placed at room temperature for 180 days, the viscosity and antimony removal effect of the products remained basically unchanged, while the coagulant prepared in Comparative Example 1 showed an increase in viscosity after being placed at room temperature for 90 days, and the antimony removal effect was significantly deteriorated, indicating that the addition of acid can improve the stability of the antimony removal coagulant of the present invention.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An antimony removal coagulant, characterized in that: The preparation method comprises the following raw materials in weight percentage: 30-55% of aluminum foil pickling solution, 38.5-65% of calcium aluminate powder, 0.1-1.5% of ferric chloride, and 1-5% of auxiliary agent; The components of the aluminum foil pickling solution include hydrochloric acid and aluminum chloride; the aluminum content in the aluminum foil acid is 4-8wt% based on Al2O3; The auxiliary agent is an inorganic acid.

2. The antimony removal coagulant according to claim 1, characterized in that: The antimony removal coagulant comprises the following raw materials in percentage by weight: 35-46% of aluminum foil pickling solution, 50-62% of calcium aluminate powder, 0.5-1.5% of ferric chloride and 2-3% of auxiliary agent.

3. The antimony removal coagulant according to claim 1, characterized in that: The inorganic acid is sulfuric acid or phosphorous acid; the concentration of the sulfuric acid is 95-98 wt %.

4. The method for preparing the antimony removal coagulant according to any one of claims 1 to 3, characterized in that: The following steps are involved: Aluminum foil acid and calcium aluminate powder are mixed to carry out polymerization reaction to obtain a polymerization reaction liquid; The polymerization reaction liquid and ferric chloride are mixed to carry out a compounding reaction to obtain a compounded reaction liquid; The composite reaction liquid and the auxiliary agent are mixed to obtain the antimony removal coagulant.

5. The preparation method according to claim 4, characterized in that: The polymerization reaction temperature is 75-88°C.

6. The preparation method according to claim 4 or 5, characterized in that: The polymerization reaction time is 1 to 4 hours.

7. The preparation method according to claim 4, characterized in that: The temperature of the compounding reaction is 75-88°C.

8. The preparation method according to claim 4 or 7, characterized in that: The time of the compounding reaction is 0.2 to 1 hour.

9. The preparation method according to claim 4, characterized in that: After the compounding reaction, the method further comprises filtering the obtained reaction liquid, and the obtained filtrate is the antimony removal coagulant.

10. Use of the antimony removal coagulant according to any one of claims 1 to 3 or the antimony removal coagulant prepared by the preparation method according to any one of claims 4 to 9 in the treatment of antimony-containing wastewater.

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