Composite separating agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to a composite separating agent as well as a preparation method and application thereof. The composite separating agent is prepared from a component A and a component B, the component A comprises a nitrogen-containing compound, organic aldehyde, ferric salt, aluminum salt, a scale inhibitor and an antirust agent; the component B comprises a scale inhibitor, an antirust agent and a flocculating agent; the scale inhibitor comprises an organic phosphonate scale inhibitor and a polycarboxylic acid scale inhibitor; the antirust agent comprises a phosphate antirust agent, a silicate antirust agent and an organic phosphonic acid antirust agent. Organic phosphonate and polycarboxylic acid are compounded to serve as the scale inhibitor, phosphate, silicate and organic phosphonic acid are compounded to serve as the antirust agent, and the scale inhibitor and the antirust agent act together with other components, so that the composite separating agent has good scale inhibition and antirust effects, paint in circulating water can be effectively removed, the utilization efficiency of the circulating water is improved, and the service life of the circulating water is prolonged. Equipment faults are reduced, and the production cost of enterprises is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a composite separation agent and a preparation method and application thereof. Background Art

[0002] In the process of painting and spraying, a large amount of circulating water is usually used, and it is usually necessary to separate the paint wastewater from the paint water. However, the water after the separation of paint and water still has a certain hardness and corrosiveness, which can easily lead to scaling, rust and blockage in the pipes, inside of the pipe pump, on the wall of the water tank, and on the valves in the paint wastewater treatment system, affecting the treatment of the paint wastewater, reducing the efficiency of water recycling, and reducing the service life of the equipment.

[0003] At present, separation agents are usually used to separate paint wastewater from water to achieve wastewater treatment and water recycling. However, the current separation agents only have the function of separating paint wastewater and cannot achieve scale and rust prevention, or the scale and rust prevention effects are poor, and scaling, rust and blockage still exist.

[0004] Therefore, it is of great significance to provide a composite separation agent with good scale inhibition and rust prevention effects. Summary of the invention

[0005] The present invention aims to solve one or more technical problems existing in the above-mentioned prior art and at least provide a beneficial choice. Specifically, the present invention provides a composite separation agent, which has good scale and rust prevention effects, and can effectively remove paint in circulating water, improve the utilization efficiency of circulating water, reduce equipment failures, and reduce enterprise production costs.

[0006] The inventive concept of the present invention: the raw material components of the composite separation agent of the present invention include component A and component B; the component A includes nitrogen-containing compounds, organic aldehydes, iron salts, aluminum salts, scale inhibitors, and rust inhibitors; the component B includes scale inhibitors, rust inhibitors, and flocculants; the scale inhibitors include organic phosphonate scale inhibitors and polycarboxylic acid scale inhibitors; the rust inhibitors include phosphate rust inhibitors, silicate rust inhibitors, and organic phosphonic acid rust inhibitors. The present invention uses a compound of organic phosphonates and polycarboxylic acids as scale inhibitors, and a compound of phosphates, silicates, and organic phosphonic acids as rust inhibitors, and works together with other components to make the composite separation agent have good scale inhibition and rust prevention effects, and can effectively remove paint in circulating water, improve the utilization efficiency of circulating water, reduce equipment failures, and reduce enterprise production costs.

[0007] Therefore, a first aspect of the present invention provides a composite separating agent.

[0008] Specifically, the raw material components of the composite separation agent include component A and component B;

[0009] The component A includes nitrogen-containing compounds, organic aldehydes, iron salts, aluminum salts, scale inhibitors, and rust inhibitors;

[0010] The B component includes scale inhibitor, rust inhibitor and flocculant;

[0011] The scale inhibitors include organic phosphonate scale inhibitors and polycarboxylic acid scale inhibitors;

[0012] The rust inhibitors include phosphate rust inhibitors, silicate rust inhibitors and organic phosphonic acid rust inhibitors.

[0013] Preferably, the nitrogen-containing compound includes at least one of melamine and urea.

[0014] Preferably, the organic aldehyde includes at least one of formaldehyde, acetaldehyde and propionaldehyde.

[0015] Preferably, the iron salt comprises ferric chloride.

[0016] Preferably, the aluminum salt comprises polyaluminum chloride.

[0017] Preferably, the flocculant comprises cationic polyacrylamide.

[0018] Preferably, in the scale inhibitor, the mass ratio of the organic phosphonate scale inhibitor to the polycarboxylic acid scale inhibitor is (0.5-1.5):1; further preferably, in the scale inhibitor, the mass ratio of the organic phosphonate scale inhibitor to the polycarboxylic acid scale inhibitor is (0.8-1.2):1; further preferably, in the scale inhibitor, the mass ratio of the organic phosphonate scale inhibitor to the polycarboxylic acid scale inhibitor is 1:1.

[0019] Specifically, organic phosphonates can form stable complexes with metal ions such as calcium and magnesium in water to prevent the formation of scale, and polycarboxylates prevent scale from depositing on metal surfaces through adsorption and dispersion. The present invention uses organic phosphonate scale inhibitors and polycarboxylic acid scale inhibitors to achieve better scale inhibition effects.

[0020] Preferably, in the rust inhibitor, the mass ratio of the phosphate rust inhibitor, the silicate rust inhibitor and the organic phosphonic acid rust inhibitor is 1:(0.3-0.7):(0.3-0.7); further preferably, in the rust inhibitor, the mass ratio of the phosphate rust inhibitor, the silicate rust inhibitor and the organic phosphonic acid rust inhibitor is 1:(0.4-0.6):(0.4-0.6); further preferably, in the rust inhibitor, the mass ratio of the phosphate rust inhibitor, the silicate rust inhibitor and the organic phosphonic acid rust inhibitor is 1:0.5:0.5.

[0021] Specifically, phosphate can form a phosphate protective film on the metal surface to prevent rust; the protective film formed by silicate has good water resistance and heat resistance; organic phosphonic acid can form a stable complex with metal ions to form a protective film on the metal surface, which has good rust prevention effect and high temperature resistance. The present invention uses a phosphate rust inhibitor, a silicate rust inhibitor and an organic phosphonic acid rust inhibitor to compound, which can achieve a better rust prevention effect.

[0022] Preferably, the organic phosphonate scale inhibitor includes at least one of aminotrimethylenephosphonic acid (ATMP) and hydroxyethylidene diphosphonic acid (HEDP).

[0023] Preferably, the polycarboxylic acid scale inhibitor includes at least one of polyacrylic acid (PAA) and polymaleic anhydride (PMA).

[0024] Preferably, the phosphate rust inhibitor includes at least one of sodium hydrogen phosphate and potassium hydrogen phosphate.

[0025] Preferably, the silicate rust inhibitor includes at least one of sodium silicate and potassium silicate.

[0026] Preferably, the organic phosphonic acid rust inhibitor includes at least one of aminotrimethylenephosphonic acid and hydroxyethylidene diphosphonic acid.

[0027] Preferably, the A component further comprises water.

[0028] Preferably, the B component further comprises at least one of a bactericide and water.

[0029] Preferably, the B component also includes a bactericide and water; and in parts by weight, the A component includes 2.2-11 parts of nitrogen-containing compounds, 3.5-11 parts of organic aldehydes, 0.9-5.5 parts of iron salts, 13-28 parts of aluminum salts, 0.9-2.2 parts of scale inhibitors, 0.9-2.2 parts of rust inhibitors, and 270-550 parts of water; the B component includes 0.9-2.2 parts of scale inhibitors, 0.9-2.2 parts of rust inhibitors, 0.9-2.2 parts of flocculants, 0.9-2.2 parts of bactericides, and 270-550 parts of water.

[0030] Further preferably, the B component also includes a bactericide and water; and in parts by weight, the A component includes 2.5-10 parts of nitrogen-containing compounds, 4-10 parts of organic aldehydes, 1-5 parts of iron salts, 15-25 parts of aluminum salts, 1-2 parts of scale inhibitors, 1-2 parts of rust inhibitors, and 300-500 parts of water; the B component includes 1-2 parts of scale inhibitors, 1-2 parts of rust inhibitors, 1-2 parts of flocculants, 1-2 parts of bactericides, and 300-500 parts of water.

[0031] Preferably, the bactericide comprises sodium hypochlorite.

[0032] The second aspect of the present invention provides a method for preparing the composite separating agent described in the first aspect of the present invention.

[0033] Specifically, the preparation method of the composite separating agent comprises the following steps:

[0034] The nitrogen-containing compound and the organic aldehyde are mixed and reacted, and then the iron salt, the aluminum salt, the scale inhibitor and the rust inhibitor are added and mixed to obtain the component A;

[0035] The raw material components of the B component are mixed to obtain the B component; the A component and the B component constitute the composite separating agent.

[0036] Preferably, the preparation process of the A component is to mix the nitrogen-containing compound, organic aldehyde and water, react, and then add the iron salt, aluminum salt, scale inhibitor and rust inhibitor to mix to obtain the A component.

[0037] Preferably, the reaction temperature is 70-90°C, and the reaction time is 0.8-1.2h; preferably, the reaction temperature is 75-85°C, and the reaction time is 0.9-1.1h.

[0038] The third aspect of the present invention provides a use of the composite separation agent described in the first aspect of the present invention in wastewater treatment.

[0039] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0040] (1) The present invention adopts a compound of organic phosphonates and polycarboxylates as scale inhibitors, and a compound of phosphates, silicates and organic phosphonic acids as rust inhibitors, and works together with other components to make the composite separation agent have good scale inhibition and rust prevention effects, and can effectively remove paint in circulating water, improve the utilization efficiency of circulating water, reduce equipment failures, and reduce enterprise production costs.

[0041] (2) The preparation process of the present invention is simple and convenient for large-scale production and application. DETAILED DESCRIPTION

[0042] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0043] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0044] Example 1

[0045] A composite separation agent, whose raw material components include component A and component B. In parts by weight, component A includes 8 parts of urea, 10 parts of formaldehyde, 1 part of ferric chloride, 15 parts of polyaluminium chloride, 2 parts of scale inhibitor (1 part of HEDP, 1 part of PAA), 2 parts of rust inhibitor (1 part of sodium hydrogen phosphate, 0.5 part of sodium silicate, 0.5 part of ATMP), and 400 parts of water; component B includes 2 parts of scale inhibitor (1 part of HEDP, 1 part of PAA), 2 parts of rust inhibitor (1 part of sodium hydrogen phosphate, 0.5 part of sodium silicate, 0.5 part of ATMP), 1 part of sodium hypochlorite, 2 parts of cationic polyacrylamide, and 400 parts of water.

[0046] A method for preparing a composite separating agent comprises the following steps:

[0047] Add urea and formaldehyde into water, stir and mix thoroughly, heat to 80°C, and keep warm for 1 hour; after cooling, add ferric chloride, polyaluminium chloride, scale inhibitor and rust inhibitor respectively, stir and mix thoroughly to obtain component A;

[0048] Add cationic polyacrylamide into water, stir and dissolve it thoroughly, then add scale inhibitor, rust inhibitor and sodium hypochlorite, stir and mix thoroughly to obtain component B; component A and component B constitute a composite separation agent.

[0049] Example 2

[0050] A composite separation agent, the raw material components of which include component A and component B, and by weight, component A includes 8 parts of urea, 10 parts of formaldehyde, 1 part of ferric chloride, 15 parts of polyaluminium chloride, 2 parts of scale inhibitor (1 part of HEDP, 1 part of PAA), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 part of potassium silicate, 0.5 part of ATMP), and 400 parts of water;

[0051] Component B includes 2 parts of cationic polyacrylamide, 2 parts of scale inhibitor (1 part of HEDP, 1 part of PAA), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 parts of potassium silicate, 0.5 parts of ATMP), 1 part of sodium hypochlorite, and 400 parts of water.

[0052] A method for preparing a composite separating agent comprises the following steps:

[0053] Add urea and formaldehyde into water, stir and mix thoroughly, heat to 80°C, and keep warm for 1 hour; after cooling, add ferric chloride, polyaluminium chloride, scale inhibitor and rust inhibitor respectively, stir and mix thoroughly to obtain component A;

[0054] Add cationic polyacrylamide into water, stir and dissolve it thoroughly, then add scale inhibitor, rust inhibitor and sodium hypochlorite, stir and mix thoroughly to obtain component B; component A and component B constitute a composite separation agent.

[0055] Example 3

[0056] A composite separation agent, the raw material components of which include component A and component B, and by weight, component A includes 8 parts of urea, 10 parts of formaldehyde, 1 part of ferric chloride, 15 parts of polyaluminium chloride, 2 parts of scale inhibitor (1 part of HEDP, 1 part of PMA), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 parts of potassium silicate, 0.5 parts of HEDP), and 400 parts of water;

[0057] Component B includes 2 parts of cationic polyacrylamide, 2 parts of scale inhibitor (1 part of HEDP, 1 part of PMA), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 parts of potassium silicate, 0.5 parts of HEDP), 1 part of sodium hypochlorite, and 400 parts of water.

[0058] A method for preparing a composite separating agent comprises the following steps:

[0059] Add urea and formaldehyde into water, stir and mix thoroughly, heat to 80°C, and keep warm for 1 hour; after cooling, add ferric chloride, polyaluminium chloride, scale inhibitor and rust inhibitor respectively, stir and mix thoroughly to obtain component A;

[0060] Add cationic polyacrylamide into water, stir and dissolve it thoroughly, then add scale inhibitor, rust inhibitor and sodium hypochlorite, stir and mix thoroughly to obtain component B; component A and component B constitute a composite separation agent.

[0061] Example 4

[0062] A composite separation agent, the raw material components of which include component A and component B, and in parts by weight, component A includes 8 parts of urea, 10 parts of formaldehyde, 1 part of ferric chloride, 15 parts of polyaluminium chloride, 2 parts of scale inhibitor (1 part of PAA, 1 part of ATMP), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 parts of potassium silicate, 0.5 parts of HEDP), and 400 parts of water;

[0063] Component B includes 2 parts of cationic polyacrylamide, 2 parts of scale inhibitor (1 part of PAA, 1 part of ATMP), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 parts of potassium silicate, 0.5 parts of HEDP), 1 part of sodium hypochlorite, and 400 parts of water.

[0064] A method for preparing a composite separating agent comprises the following steps:

[0065] Add urea and formaldehyde into water, stir and mix thoroughly, heat to 80°C, and keep warm for 1 hour; after cooling, add ferric chloride, polyaluminium chloride, scale inhibitor and rust inhibitor respectively, stir and mix thoroughly to obtain component A;

[0066] Add cationic polyacrylamide into water, stir and dissolve it thoroughly, then add scale inhibitor, rust inhibitor and sodium hypochlorite, stir and mix thoroughly to obtain component B; component A and component B constitute a composite separation agent.

[0067] Example 5

[0068] A composite separation agent, the raw material components of which include component A and component B, and by weight, component A includes 10 parts of urea, 5 parts of formaldehyde, 1 part of ferric chloride, 25 parts of polyaluminium chloride, 2 parts of scale inhibitor (1 part of PMA, 1 part of ATMP), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 part of potassium silicate, 0.5 part of HEDP), and 500 parts of water;

[0069] Component B includes 2 parts of cationic polyacrylamide, 2 parts of scale inhibitor (1 part of PMA, 1 part of ATMP), 2 parts of rust inhibitor (1 part of potassium hydrogen phosphate, 0.5 parts of potassium silicate, 0.5 parts of HEDP), 1 part of sodium hypochlorite, and 400 parts of water.

[0070] A method for preparing a composite separating agent comprises the following steps:

[0071] Add urea and formaldehyde into water, stir and mix thoroughly, heat to 80°C, and keep warm for 1 hour; after cooling, add ferric chloride, polyaluminium chloride, scale inhibitor and rust inhibitor respectively, stir and mix thoroughly to obtain component A;

[0072] Add cationic polyacrylamide into water, stir and dissolve it thoroughly, then add scale inhibitor, rust inhibitor and sodium hypochlorite, stir and mix thoroughly to obtain component B; component A and component B constitute a composite separation agent.

[0073] Comparative Example 1

[0074] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses an equal amount of PAA to replace HEDP, that is, does not contain HEDP, and the rest is the same as Example 1.

[0075] Comparative Example 2

[0076] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 uses an equal amount of HEDP to replace PAA, that is, does not contain PAA, and the rest is the same as Example 1.

[0077] Comparative Example 3

[0078] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 uses an equal amount of sodium silicate to replace sodium hydrogen phosphate, that is, does not contain sodium hydrogen phosphate, and the rest is the same as Example 1.

[0079] Comparative Example 4

[0080] The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 uses an equal amount of sodium hydrogen phosphate to replace sodium silicate, that is, does not contain sodium silicate, and the rest is the same as Example 1.

[0081] Comparative Example 5

[0082] The difference between Comparative Example 5 and Example 1 is that Comparative Example 5 uses an equal amount of sodium hydrogen phosphate to replace ATMP, that is, does not contain ATMP, and the rest is the same as Example 1.

[0083] Performance Testing

[0084] The composite separation agents prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests, and the specific test items and test methods are as follows:

[0085] Paint removal rate: Through the coagulation sedimentation or coagulation flotation experiment of the paint spraying circulating water, by comparing the paint component content before and after adding the agent of the present invention, the paint removal rate is calculated to obtain the paint removal effect of the agent of the present invention;

[0086] Scale inhibition rate: The scale inhibition performance of the composite separation agent was investigated through a static scale inhibition test. The experimental steps are as follows:

[0087] (1) Prepare water sample: according to the experimental requirements, take 20 kg of paint circulating water;

[0088] (2) Grouping: The water samples were divided into two groups, one group was added with the composite separation agent, and the other group was added with the composite separation agent of the blank group as a control (the blank group was compared with Example 1, but no scale inhibitor and rust inhibitor were added, and the rest was the same as Example 1);

[0089] (3) Insulation: Place the two groups of water samples in a constant temperature device at the same temperature (30°C) for 24 hours;

[0090] (4) Observation and analysis: After 24 hours, observe the scale formation in the water sample and make judgments based on indicators such as precipitation amount, turbidity, and calcium ion content.

[0091] (5) Calculation of scale inhibition rate: Calculate the scale inhibition rate of the composite separation agent based on the experimental results. Scale inhibition rate = (scale generation in the control water sample - scale generation in the water sample with composite separation agent added) / scale generation in the control water sample × 100%.

[0092] Static anti-rust rate: The static immersion test is used to test the static anti-rust rate. The experimental steps are as follows:

[0093] (1) A carbon steel metal test piece (stainless steel, cast iron, etc. may also be used) is polished with sandpaper, then cleaned with an organic solvent and dried, and the treated metal test piece is completely immersed in a container filled with paint circulating water to ensure that the metal test piece is completely immersed, and the composite separation agent of Examples 1-5 and Comparative Examples 1-5 is added respectively, and the container is placed in a constant temperature environment at room temperature (25° C.);

[0094] (2) During the immersion process, regularly observe the surface changes of the carbon steel metal test piece, record the time of rusting, the degree of rusting (such as the size, color, density, etc. of the rust spots), and the changes in the solution (such as color, transparency, etc.). The immersion time is 3 days;

[0095] (3) After the experiment, the carbon steel metal test piece was taken out, cleaned and dried, and then the microstructure of the test piece was observed using a metallographic microscope to obtain the rust conditions of the two groups of experiments and calculate their anti-rust efficiency.

[0096] Static rust prevention rate: A dynamic simulation experiment is used to test the static rust prevention rate. The experimental steps are as follows:

[0097] (1) Construct a circulation system including a water pump, pipes, valves, and a liquid storage tank so that the composite separation agent can circulate continuously in the system. The materials of the pipes and the liquid storage tank should be similar to those in the actual application scenario and have good corrosion resistance;

[0098] (2) A test section is set up in the circulation system to install a carbon steel metal test piece. The design of the test section should be able to simulate the structure and working conditions of the actual equipment or pipeline. For example, the same pipe diameter and roughness as the actual pipeline can be used; and monitoring equipment such as temperature sensors, pressure sensors, and flow sensors should be installed to monitor the temperature, pressure, flow and other parameters in real time during the experiment to ensure the stability and accuracy of the experimental conditions;

[0099] (3) Add an appropriate amount of paint circulating water into the liquid storage tank and divide it into two groups. One group is added with the composite separation agent of Examples 1-5 and Comparative Examples 1-5 respectively, and the other group is added with the composite separation agent of the blank group as a control water sample (the blank group is compared with Example 1, but no scale inhibitor and rust inhibitor are added, and the rest is the same as Example 1); then install the carbon steel metal test piece in the test section to ensure that the test piece is in full contact with the circulating water; start the water pump to circulate the composite separation agent in the circulation system, and adjust the parameters such as flow rate and pressure to achieve the predetermined experimental conditions;

[0100] (4) During the experiment, the surface changes of the carbon steel metal test pieces were observed regularly and the relevant monitoring data were recorded. The experiment lasted for 7 days. After the experiment, the carbon steel metal test pieces were cleaned and dried, and then the microstructure of the test pieces was observed using a metallographic microscope to obtain the corrosion conditions of the two groups and calculate their anti-rust rates. Anti-rust rate = (the amount of rust generated in the control water sample - the amount of rust generated in the water sample with the composite separation agent) / the amount of rust generated in the control water sample × 100%.

[0101] The performance test results of the composite separating agents prepared in Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0102] Table 1: Performance test results of composite separation agents of Examples 1-5 and Comparative Examples 1-5

[0103]

[0104] It can be seen from Table 1 that the composite separation agent prepared by the present invention has a good paint removal effect, and at the same time has a good scale inhibition and rust prevention effect. The water after the paint water separation is not easy to scale, rust and clog in the pipes, pipe pumps, valves and other locations in the paint wastewater treatment system, thereby reducing equipment failures, improving the utilization efficiency of circulating water, and reducing enterprise production costs.

[0105] Comparative Example 1 does not contain HEDP, and Comparative Example 2 does not contain PAA, so the scale inhibition rates of Comparative Examples 1 and 2 are significantly lower than that of Example 1, indicating that HEDP and PAA are indispensable, and the combined effect of the three makes the composite separation agent have a good scale inhibition effect.

[0106] Comparative Example 3 does not contain sodium hydrogen phosphate, Comparative Example 4 does not contain sodium silicate, and Comparative Example 5 does not contain ATMP, so that the rust prevention rates of Comparative Examples 3-5 are all lower than those of Example 1, indicating that sodium hydrogen phosphate, sodium silicate and ATMP are indispensable, and the three work together to make the composite separation agent have a good rust prevention effect.

[0107] In summary, the present invention adopts a compound of organic phosphonates and polycarboxylates as scale inhibitors, and a compound of phosphates, silicates and organic phosphonic acids as rust inhibitors, and works together with other components to make the composite separation agent have good scale inhibition and rust prevention effects, and can effectively remove paint in circulating water, improve the utilization efficiency of circulating water, reduce equipment failures, and reduce enterprise production costs.

[0108] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A composite separating agent, characterized in that: The raw material components include component A and component B; The component A includes nitrogen-containing compounds, organic aldehydes, iron salts, aluminum salts, scale inhibitors, and rust inhibitors; The B component includes scale inhibitor, rust inhibitor and flocculant; The scale inhibitors include organic phosphonate scale inhibitors and polycarboxylic acid scale inhibitors; The rust inhibitors include phosphate rust inhibitors, silicate rust inhibitors and organic phosphonic acid rust inhibitors.

2. The composite separating agent according to claim 1, characterized in that The nitrogen-containing compound includes at least one of melamine and urea; and / or the organic aldehyde includes at least one of formaldehyde, acetaldehyde and propionaldehyde; and / or the iron salt includes ferric chloride; and / or the aluminum salt includes polyaluminum chloride; and / or the flocculant includes cationic polyacrylamide.

3. The composite separating agent according to claim 1, characterized in that In the scale inhibitor, the mass ratio of the organic phosphonate scale inhibitor to the polycarboxylic acid scale inhibitor is (0.5-1.5):1; and / or, in the rust inhibitor, the mass ratio of the phosphate rust inhibitor, the silicate rust inhibitor and the organic phosphonic acid rust inhibitor is 1:(0.3-0.7):(0.3-0.7).

4. The composite separating agent according to claim 3, characterized in that The organic phosphonate scale inhibitor includes at least one of aminotrimethylenephosphonic acid and hydroxyethylidene diphosphonic acid; and / or the polycarboxylic acid scale inhibitor includes at least one of polyacrylic acid and polymaleic anhydride.

5. The composite separating agent according to claim 3, characterized in that The phosphate rust inhibitor includes at least one of sodium hydrogen phosphate and potassium hydrogen phosphate; and / or, the silicate rust inhibitor includes at least one of sodium silicate and potassium silicate; and / or, the organic phosphonic acid rust inhibitor includes at least one of aminotrimethylenephosphonic acid and hydroxyethylidene diphosphonic acid.

6. The composite separating agent according to claim 1, characterized in that The component A further comprises water; and / or the component B further comprises at least one of a bactericide and water.

7. The composite separating agent according to claim 6, characterized in that The B component also includes a bactericide and water; and in parts by weight, the A component includes 2.2-11 parts of nitrogen-containing compounds, 3.5-11 parts of organic aldehydes, 0.9-5.5 parts of iron salts, 13-28 parts of aluminum salts, 0.9-2.2 parts of scale inhibitors, 0.9-2.2 parts of rust inhibitors, and 270-550 parts of water; the B component includes 0.9-2.2 parts of scale inhibitors, 0.9-2.2 parts of rust inhibitors, 0.9-2.2 parts of flocculants, 0.9-2.2 parts of bactericides, and 270-550 parts of water.

8. The method for preparing the composite separating agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: The nitrogen-containing compound and the organic aldehyde are mixed and reacted, and then the iron salt, the aluminum salt, the scale inhibitor and the rust inhibitor are added and mixed to obtain the component A; The raw material components of the B component are mixed to obtain the B component; the A component and the B component constitute the composite separating agent.

9. The preparation method according to claim 8, characterized in that: The preparation process of the A component is to mix the nitrogen-containing compound, organic aldehyde and water, react, and then add the iron salt, aluminum salt, scale inhibitor and rust inhibitor to mix to obtain the A component.

10. Use of the composite separation agent according to any one of claims 1 to 7 in wastewater treatment.

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