CN107117738B

CN107117738B - Manganese ore area wastewater treatment method

Info

Publication number: CN107117738B
Application number: CN201710270851.1A
Authority: CN
Inventors: 刘正乾; 王琪; 吴晓晖; 涂嘉玲; 闫娅慧; 崔玉虹; 章北平
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2017-04-24
Filing date: 2017-04-24
Publication date: 2019-12-17
Anticipated expiration: 2037-04-24
Also published as: CN107117738A

Abstract

The invention discloses a manganese ore area wastewater treatment method, which adopts a combined process of ettringite and coagulating sedimentation to treat a water body of a manganese ore area, wherein Ca is contained in an alkaline aqueous solution²⁺、Al³⁺、SO₄ ^2‑And OH^‑Mutually combined to form a compound Ca which is insoluble in water₆Al₂(SO₄)₃(OH)₁₂·26H₂O, and the insoluble compound is converted into flocs by mixed flocculation, SO that the simultaneous removal of SO is achieved in the form of precipitates₄ ^2－And Ca²⁺In addition to the presence of Mg in the water sample²⁺Or heavy metal ions can pass through OH under alkaline conditions^‑Removing the generated precipitate, and flocculating and precipitating humic acid and residual Al in the wastewater³⁺And (5) removing. The method is simple and convenient to operate and easy to implement, precipitates generated during the removal of sulfate radicals are ettringite, the method is free from environmental pollution, and the method can be used for building materials, improves the strength of concrete and realizes secondary utilization.

Description

Manganese ore area wastewater treatment method

Technical Field

The invention belongs to the technical field of sewage treatment, and particularly relates to a method for treating manganese ore area wastewater.

Background

China has abundant manganese ore resources, and water bodies in mining areas and surrounding areas are polluted to different degrees while the manganese ore is exploited vigorously. Sulfuric acid is commonly used in the process of mining and processing manganese ores, so that the waste water contains a large amount of sulfate, and the waste water is discharged into a natural water body without being effectively treated, so that the water body in a manganese ore area contains high-concentration sulfate radicals; and areAnd the soil in the mining area is subjected to H in acid rain₂CO₃And H₂SO₃Erosion, CaCO₃The continuous dissolution leads the hardness of the water to be continuously improved, simultaneously, the mineralization degree of the water body and the river water in the mining area is higher, and the salt effect generated by partially supplying the underground water leads the contents of calcium and magnesium in the water to be rapidly improved; spring water and rainwater on mountains around the mining area flow into the water body of the manganese mining area through surface runoff, organic matters and the like in soil flowing through are brought into the water body, so that the content of the organic matters in the water is increased, and meanwhile, the water body of the manganese mining area is rich in heavy metal elements such as manganese, nickel, chromium and the like.

At present, the common methods for removing sulfate radicals mainly comprise a barium salt method, wherein a barium sulfate precipitate is generated and removed, and the method can cause secondary pollution and has higher cost; calcium salt method, the calcium sulfate precipitation that is produced is removed, but the removal rate is low; the freezing method has large investment and high energy consumption, and is rarely applied in industry at present. In recent years, methods such as adsorption, ion exchange, membrane filtration, and the like have been developed. However, the existing methods are mainly limited to the removal of sulfate radicals in chlor-alkali wastewater, and metallurgical wastewater or mining area water containing high-concentration sulfate radicals and low-concentration other metal ions and organic matters is not treated by a simple method at the present stage.

Disclosure of Invention

In view of the above-mentioned drawbacks or needs for improvement in the prior art, the present invention provides a method for treating wastewater in a manganese ore region, and more particularly, to a method for treating wastewater containing sulfate radicals and other metal ions and organic matter by adding NaAlO to the wastewater₂Forming ettringite precipitate Ca with CaO₆Al₂(SO₄)₃(OH)₁₂·26H₂O to remove SO quickly, economically and effectively₄ ^2-、Ca² ⁺And Al³⁺And Mg in water²⁺、Mn²⁺And Ni²⁺The method has the advantages of simple and convenient operation, high reaction speed, capability of simultaneously treating various substances in the wastewater, no secondary pollution and capability of using the generated precipitated ettringite as a concrete expanding agent.

In order to realize the purpose, the invention provides a manganese ore area wastewater treatment method, which comprises the following steps:

(1) adding Ca to waste water containing sulfate radical²⁺:Al³⁺:SO₄ ^2-NaAlO is added at the initial molar ratio of 1.75-2.22: 0.48-0.71: 1₂And CaO, the pH of the wastewater solution is adjusted to 11-12.5 to ensure that Ca is contained in the solution²⁺、Al³⁺、SO₄ ^2-And OH^-Combine with each other to form a hardly water-soluble complex Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O；

(2) stirring the solution containing the compound which is difficult to dissolve in water and formed in the step (1) at the rotating speed of 150 r/min-450 r/min for 45 min-120 min, and mixing and flocculating the Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂Converting O into floc, standing for 30min, and removing Ca in form of precipitate₆Al₂(SO₄)₃(OH)₁₂·26H₂O, thereby simultaneously removing SO in the solution₄ ^2－And Ca²⁺；

(3) Adjusting the pH value of the water sample obtained in the step (2) after the sediment is removed to 5-8, and rapidly stirring for 30s at a rotating speed of 250r/min to enable aluminum salt in the solution and humic acid to generate copolymerization and complexation reaction so as to generate aluminum salt flocs, wherein the aluminum salt flocs are mutually collided and increased while stirring;

(4) Slowly stirring for 15min at the rotating speed of 40r/min so that the aluminum salt flocs collide with each other and continue to increase, and simultaneously preventing the increased aluminum salt flocs from being crushed;

(5) And (4) standing the water sample obtained in the step (4) for 30min to completely remove aluminum salt flocs complexed with humic acid molecules in a precipitate form.

Further preferably, the step (1) further includes: mg in wastewater under alkaline conditions²⁺、Mn²⁺And Ni²⁺Metal ion passing through OH^-And removing the precipitate generated by combination.

As a further preference, the stepsThe step (3) further includes: al in wastewater³⁺By formation of Al (OH)₃Removal of the precipitate, the Al (OH)₃Is amorphous hydroxide, and is used for capturing humic acid molecules (i.e. net sweeping flocculation) and simultaneously removing SO in a dissolved state₄ ^2－And Ca²⁺Etc. are adsorbed on the surface of the water to precipitate, thereby further purifying the water.

As further preferred, the treatment temperature of the steps (1) to (5) is not more than 40 ℃.

Further preferably, in step (1), Ca is preferably added²⁺:Al³⁺:SO₄ ^2-NaAlO is added at the initial molar ratio of 2.06-2.22: 0.56-0.63: 1₂And CaO, and adjusting the pH value to 11-12.14 to enable Ca in the solution to be in the range of²⁺、Al³⁺、SO₄ ^2-And OH^-Are combined with each other to form Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O; the stirring time in the step (2) is preferably 60min to 90 min; in the step (3), preferably, the pH value of the water sample after the sediment is removed is adjusted to 6-7; the treatment temperature in the steps (1) to (5) is preferably not more than 30 ℃.

As further preferred, 3.5mmol/L NaAlO is preferably added in step (1)₂And CaO in an amount of 7.1mmol/L to make Ca in the water sample²⁺:Al³⁺:SO₄ ^2-The initial molar ratio is 2.06:0.56:1, the pH is preferably adjusted to 12.14; the stirring speed and the stirring time in the step (2) are preferably 300r/min and 60 min; in the step (3), preferably, the pH value of the water sample after removing the precipitate is adjusted to 6.5; the treatment temperature in the steps (1) to (5) is preferably 10-20 DEG C

Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

(1) The invention removes SO in wastewater₄ ^2－While the Ca in the water body can be removed²⁺、Mg²⁺、Mn²⁺、Ni²⁺、Cr²⁺And Cd²⁺The plasma metal ions are removed as a precipitate and the final effluent pH is guaranteed to be in the neutral range.

(2) The inventionThe humic acid and the residual Al in the wastewater are precipitated in a flocculation way through copolymerization and complexation reaction between the aluminum salt and the humic acid³⁺Removing and simultaneously dissolving SO₄ ^2－And Ca²⁺And the aluminum salt flocs can also efficiently remove the turbidity of the water body in the process.

(3) In the process of treating the high-concentration sulfate-containing wastewater, no toxic substance is introduced, so that secondary pollution to water bodies is avoided; the method has the advantages of simple and convenient operation, easy implementation and lower cost of the added reagent, the precipitate generated during the removal of sulfate radicals is ettringite, the method has no pollution to the environment, and the method can be used for building materials, improves the strength of concrete and realizes secondary utilization.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The main reaction principle of the invention is as follows:

AlO₂ ^-+2H₂O+2OH^-＝[Al(OH)₆]^3-；

6Ca²⁺+2[Al(OH)₆]^3-+24H₂O＝{Ca₆[Al(OH)₆]₂.24H₂O}⁶⁺；

{Ca₆[Al(OH)₆]₂.24H₂O}⁶⁺+3SO₄ ^2-+2H₂O＝{Ca₆[Al(OH)₆]₂(SO₄)₃.26H₂O}；

The invention makes Ca²⁺、Al³⁺、SO₄ ^2-And OH^-Mutually combined in an alkaline aqueous solution to form a compound which is difficult to dissolve in waterCa₆Al₂(SO₄)₃(OH)₁₂·26H₂O, converting the insoluble complex into flocs by mixed flocculation, and removing SO in the form of precipitate₄ ^2－And Ca²⁺The effect of (1). In addition, if Mg exists in the water sample²⁺Or other heavy metal ions, also under alkaline conditions by reaction with OH^-And removing the precipitate generated by combination. Then, the pH value of the water sample is adjusted to enable the aluminum salt and the humic acid to generate copolymerization and complexation reaction, and then the humic acid and the residual Al in the wastewater are precipitated in a flocculation way³⁺Removing and simultaneously dissolving SO₄ ^2－And Ca²⁺Etc. are adsorbed on the surface of the water to precipitate, thereby further purifying the water.

The invention provides a manganese ore area wastewater treatment method, which treats water in a manganese ore area by using an ettringite and coagulating sedimentation combined process to treat wastewater containing high-concentration sulfate radicals, low-concentration other metal ions and organic matters, and comprises the following steps:

Wherein, in the step (1), since the solution is alkaline, Mg in the wastewater is present²⁺、Mn²⁺And Ni²⁺The plasma metal ions can pass through with OH^-removing the combined generated precipitate; in the step (3), when the pH value of the water sample is adjusted to 5-8, Al in the wastewater³⁺except in the form of polymer (mainly polyaluminium chloride), Al in the wastewater³⁺Can also be produced by forming Al (OH)₃The precipitate is removed, and the amorphous hydroxide can capture humic acid molecules (i.e. net-sweeping flocculation) and can also remove SO in a dissolved state₄ ^2－And Ca²⁺The aluminum salt flocs can also efficiently remove the turbidity of the water body in the process of further purifying the water quality by adsorbing the aluminum salt flocs on the surface of the hydroxide for precipitation; the treatment temperature of each step is not more than 40 ℃ so as to ensure the removal rate of sulfate radicals.

The preferred scheme of the invention is as follows:

(1) Adding Ca to waste water containing sulfate radical²⁺:Al³⁺:SO₄ ^2-NaAlO is added at the initial molar ratio of 2.06-2.22: 0.56-0.63: 1₂And CaO, and adjusting the pH value to 11-12.14 to enable Ca in the solution to be in the range of²⁺、Al³⁺、SO₄ ^2-And OH^-Combining with each other to form a compound which is difficult to dissolve in water;

(2) stirring at a rotating speed of 150 r/min-450 r/min for 60 min-90 min, converting the indissolvable compound into flocs through mixing flocculation, standing for 30min, and then removing SO in a precipitation form₄ ^2－And Ca²⁺；

(3) Adjusting the pH value of the water sample after the sediment is removed to 6-7, and rapidly stirring the water sample at a rotating speed of 250r/min for 30s to enable the aluminum salt and the humic acid to generate copolymerization and complexation reaction, and simultaneously enabling aluminum salt flocs to collide with each other and increase;

(4) Slowly stirring for 15min at the rotating speed of 40r/min, so that the aluminum salt flocs collide with each other and continue to increase, and simultaneously, the increased aluminum salt flocs are prevented from being crushed;

(5) Standing the water sample for 30min to completely remove aluminum salt floc complexed with humic acid molecules in a form of precipitation;

The reaction temperature of the scheme is 10-20 ℃.

the following are specific examples of the present invention:

Example 1

In the embodiment, a polluted water body in a certain manganese ore area in Guangxi province is selected, the sulfate radical concentration in the water is 606.0mg/L, the calcium ion concentration is 236.4mg/L, the magnesium ion concentration is 36.85mg/L, the manganese ion concentration is 4.51mg/L, the pH is 6.99, and other water quality parameters are shown in Table 1, and 10mg/L of humic acid is added into the water sample to test the effect of removing organic matters. The treatment temperature for removing sulfate radicals and other metal ions and humic acid by the process of the invention is 20 ℃.

S1, adding 3.5mmol/L NaAlO₂7.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-The initial molar ratio was 2.06:0.56:1, at which time the water sample pH was 12.14;

S2, stirring at the rotating speed of 300r/min for 60min, standing for 30min, and removing precipitates;

S3, adjusting the pH value of the water sample to 6.5, and rapidly stirring for 30s at a rotating speed of 250 r/min;

S4, slowly stirring for 15min at the rotating speed of 40 r/min;

S5, standing the water sample for 30min, measuring the turbidity of the supernatant and the residual amount of humic acid, filtering the supernatant by using a 0.45-micron membrane, and detecting the concentration of each ion in the treated effluent by using ICP (inductively coupled plasma), wherein the negative indicates that the ion is not detected in Table 1.

TABLE 1 quality parameter table for raw water and treated effluent

Example 2

In this example, a contaminated water body in a manganese ore region in Guangxi was selected, and the water quality parameters are shown in Table 1. The treatment temperature was 20 ℃.

Example 1 was repeated with the same procedure as described except that 3.0mmol/L NaAlO was added in the step S1₂7.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-the initial molar ratio was 2.06:0.48:1 and the pH was 12.14. The concentrations of the ions in the effluent after the treatment are shown in Table 1.

Example 3

example 1 was repeated with the same procedure as described except that 4.0mmol/L NaAlO was added in the step S1₂7.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-The initial molar ratio was 2.06:0.63:1 and the pH was 12.14. The concentrations of the ions in the effluent after the treatment are shown in Table 1.

Example 4

Example 1 was repeated with the same procedure as described except that 4.5mmol/L NaAlO was added in the step S1₂7.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-The initial molar ratio was 2.06:0.71:1 and the pH was 12.14. The concentrations of the ions in the effluent after the treatment are shown in Table 1.

The results of examples 1 to 4 show that when n (AlO)₂ ^－):n(SO₄ ^2－)<0.71(AlO₂ ^－＝4.5mM)When, with NaAlO₂Increase in the amount of addition, SO₄ ^2－The removal rate is obviously increased when n (AlO)₂ ^－):n(SO₄ ^2－) SO 0.56₄ ^2－The removal rate reaches over 59.3 percent, and SO is generated after the effluent is adjusted back to the pH value for flocculation and precipitation₄ ^2－The effluent concentration reaches the standard, and the addition amount of aluminum salt is not excessive from the practical engineering cost, so that the invention considers that NaAlO is excessive₂The addition amount is preferably 3.5-4.0 mmol/L, i.e. n (AlO)₂ ^－):n(SO₄ ^2－) 0.56-0.63: 1, wherein n (AlO) is selected₂ ^－):n(SO₄ ^2－) The optimum condition was 0.56.

Example 5

Example 1 was repeated with the same procedure as described except that 3.5mmol/L NaAlO was added in the step S1₂5.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-The initial molar ratio was 1.75:0.56:1 and the pH was 12.14. The concentrations of the ions in the effluent after the treatment are shown in Table 2.

Example 6

Example 1 was repeated with the same procedure as described except that 3.5mmol/L NaAlO was added in the step S1₂6.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-The initial molar ratio was 1.90:0.56:1 and the pH was 12.14. The concentrations of the ions in the effluent after the treatment are shown in Table 2.

Example 7

Example 1 was repeated with the same procedure as described except that 3.5mmol/L NaAlO was added in the step S1₂8.1mmol/L CaO, Ca in the water sample²⁺/Al³⁺/SO₄ ^2-The initial molar ratio was 2.22:0.56:1 and the pH was 12.14. The concentrations of the ions in the effluent after the treatment are shown in Table 2.

TABLE 2 influence of CaO addition on effluent quality

The results of example 1 and examples 5 to 7 show that Ca is present²⁺<At 7.1mmol/L, SO increased with the addition of CaO₄ ^2-The removal rate of (2) is gradually increased; when Ca is present²⁺SO when not equal to 7.1mmol/L₄ ^2-The removal rate of (2) is over 59.3 percent, and then SO is obtained after the effluent is adjusted to the pH value for flocculation and precipitation₄ ^2-The concentration of the discharged water reaches the standard; at this pH, Ca is increased continuously²⁺Concentration, SO₄ ^2-The removal rate of (2) is only slightly reduced, and when CaO is continuously added without controlling the pH value of the solution to be constant, the pH value exceeds the optimal pH value, so that ionized Ca²⁺But instead decreases. Therefore, the amount of CaO added is preferably 7.1 to 8.1mmol/L, i.e., n (Ca)²⁺):n(SO₄ ^2－) 2.06-2.22: 1. In n (AlO)₂ ^－):n(SO₄ ^2-) When the amount of CaO added is 0.56, the optimum amount of CaO to be added is 7.1 mmol/L.

Example 8

Example 1 was repeated with the same procedure as described except that the pH was adjusted to 11.0 in the step S1, and the test was performed under such conditions. The concentrations of the ions in the effluent after the treatment are shown in Table 3.

Example 9

Example 1 was repeated with the same procedure as described except that the test was performed under the condition that the pH was adjusted to 12.0 in the step S1. The concentrations of the ions in the effluent after the treatment are shown in Table 3.

Example 10

Example 1 was repeated with the same procedure as described except that the test was performed under the condition that the pH was adjusted to 12.5 in the step S1. The concentrations of the ions in the effluent after the treatment are shown in Table 3.

TABLE 3 influence of pH on the quality of the effluent

The results of example 1 and examples 8 to 10 show that SO was present at a pH of 11 to 12.14₄ ^2－The removal rate of (A) increases with increasing pH, while Ca increases²⁺And residual aluminum decreases with increasing pH; SO at pH 12.14₄ ^2－The removal rate of (A) is the highest, and at this time SO is obtained₄ ^2－The removal rate is 59.3%; residual SO when the pH increased from 12.14 to 12.5₄ ^2－The concentration did not fall and rose back to 330.54 mg/L. The invention considers that SO is generated when the pH value is 11-12.14₄ ^2－The removal effect of (2) is better. SO when pH reaches 12.14₄ ^2－The removal effect is best, the pH value is that CaO and NaAlO are added₂And (4) selecting the pH value as the optimal initial pH value by taking the initial pH value into consideration.

Example 11

Example 1 was repeated with the same procedure as described, except that stirring was carried out at a rotational speed of 150r/min for 60min in step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 4.

Example 12

Example 1 was repeated with the same procedure as described except that stirring was carried out at a rotational speed of 450r/min for 60min in step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 4.

TABLE 4 rotation speed vs. effluent turbidity, SO₄ ^2－And influence of conductivity

the results of example 1, example 11 and example 12 show that increasing the stirring speed to 450rpm accelerates the reaction rate, SO that the higher the stirring speed, the higher the SO content, the same reaction time of 60 minutes₄ ^2－The higher the removal rate, the lower the conductivity and the lower the turbidity of the effluent. But in order to prevent the flocs from being broken, the rotating speed is 300 r/min.

Example 13

In this example, a contaminated water body in a manganese ore region in Guangxi was selected, and the water quality parameters are shown in Table 1.

Example 1 was repeated with the same procedure as described except that this example was carried out at 10 ℃. The concentrations of the ions in the effluent after the treatment are shown in Table 5.

Example 14

Example 1 was repeated with the same procedure as described except that this example was carried out at 30 ℃ respectively. The concentrations of the ions in the effluent after the treatment are shown in Table 5.

TABLE 5 reaction temperature vs. effluent turbidity, SO₄ ^2－And influence of conductivity

The results of example 1, example 13 and example 14 show that SO increases with increasing water temperature to 30 deg.C₄ ^2－Slightly reduced removal rate of Ca²⁺And a corresponding increase in the amount of residual Al, prove to be detrimental to the removal of SO when the temperature is raised to 30 DEG C₄ ^2－And SO at 10 ℃ and 20 DEG C₄ ^2－、Ca²⁺The removal rate of the residual Al is not very different. As can be seen from Table 5, low temperature vs SO₄ ^2－The removal rate is not greatly influenced, and when the water temperature reaches 30 ℃, the effluent SO is₄ ^2－The standard is not reached. Therefore, the temperature range considered suitable by the invention is 10-20 ℃, and 20 ℃ is taken as the optimal experimental temperature.

Example 15

Example 1 was repeated with the same procedure as described except that stirring was carried out at a rotational speed of 300r/min for 45min in the step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 6.

Example 16

Example 1 was repeated with the same procedure as described except that stirring was carried out at a rotational speed of 300r/min for 75min in the step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 6.

Example 17

Example 1 was repeated with the same procedure as described except that stirring was carried out at a rotational speed of 300r/min for 90min in the step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 6.

Example 18

Example 1 was repeated with the same procedure as described except that stirring was carried out at a rotational speed of 300r/min for 105min in the step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 6.

Example 19

Example 1 was repeated with the same procedure as described except that stirring was carried out at a rotational speed of 300r/min for 120min in the step S2. The concentrations of the ions in the effluent after the treatment are shown in Table 6.

TABLE 6 influence of reaction time on effluent quality

The results of example 1 and examples 15-19 show that SO is present within 2 hours of stirring₄ ^2－The concentration of (a) decreases rapidly first and then becomes slowly decreasing. Comprehensively, the reaction time considered to be suitable by the invention is 60 min-90 min, and 60min is taken as the optimal reaction time.

Example 20

Example 1 was repeated with the same procedure as described except that the pH of the water sample was adjusted to 5 in the step S3. The concentrations of the ions in the effluent after the treatment are shown in Table 7.

Example 21

Example 1 was repeated with the same procedure as described except that the pH of the water sample was adjusted to 6 in the step S3. The concentrations of the ions in the effluent after the treatment are shown in Table 7.

Example 22

Example 1 was repeated with the same procedure as described except that the pH of the water sample was adjusted to 7 in the step S3. The concentrations of the ions in the effluent after the treatment are shown in Table 7.

Example 23

example 1 was repeated with the same procedure as described except that the pH of the water sample was adjusted to 8 in the step S3. The concentrations of the ions in the effluent after the treatment are shown in Table 7.

TABLE 7 Effect of pH on humic acid removal

The results of example 1 and examples 20 to 23 show that pH has a great influence on the effect of removing humus. As the pH increases, the removal of humic acid increases first and starts to decrease after reaching the maximum value. Experimental data show that the suitable pH range is 6-7, and the optimum pH value of coagulation is about 6.5.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. a manganese ore area wastewater treatment method is characterized by comprising the following steps:

(1) Adding Ca to waste water containing sulfate radical²⁺:Al³⁺:SO₄ ^2-NaAlO is added at the initial molar ratio of 2.06-2.22: 0.56-0.63: 1₂and CaO, adjusting the pH of the wastewater solution to 11-12.14 to enable Ca in the solution to be in the range of²⁺、Al³⁺、SO₄ ^2-And OH^-Combine with each other to form a hardly water-soluble complex Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂o, Mg in wastewater under alkaline conditions²⁺、Mn²⁺And Ni²⁺Metal ion passing through OH^-Removing the combined generated precipitate;

(2) Stirring the solution containing the compound which is difficult to dissolve in water and formed in the step (1) at the rotating speed of 150 r/min-450 r/min for 60 min-90 min, and mixing and flocculating the Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂Converting O into floc, standing for 30min, and removing Ca in form of precipitate₆Al₂(SO₄)₃(OH)₁₂·26H₂O, thereby simultaneously removing SO in the solution₄ ^2－And Ca²⁺；

(3) Adjusting the pH value of the water sample subjected to precipitate removal obtained in the step (2) to 6-7, and rapidly stirring at a rotating speed of 250r/min for 30s to enable aluminum salt in the solution and humic acid to generate copolymerization and complexation reaction so as to generate aluminum salt flocs, wherein the aluminum salt flocs are mutually collided and increased while being stirred;

(5) standing the water sample obtained in the step (4) for 30min to completely remove aluminum salt flocs complexed with humic acid molecules in a form of precipitation, and carrying out copolymerization and complexation reaction between aluminum salt and humic acid to flocculate and precipitate humic acid and residual Al in the wastewater³⁺Removing and simultaneously dissolving SO₄ ^2－And Ca²⁺The aluminum salt floc can also efficiently remove the turbidity of the water body in the process of further purifying the water quality by adsorbing the aluminum salt floc on the surface of the aluminum salt floc for precipitation, and the treatment temperature of the steps (1) - (5) is 10-20 ℃.

2. The method for treating wastewater in a manganese ore area according to claim 1, wherein 3.5mmol/L NaAlO is added in the step (1)₂And CaO in an amount of 7.1mmol/L to make Ca in the water sample²⁺:Al³⁺:SO₄ ^2-The initial molar ratio was 2.06:0.56:1, the pH was adjusted to 12.14; the stirring speed and the stirring time in the step (2) are 300r/min and 60 min; and (3) adjusting the pH value of the water sample after removing the precipitate to 6.5.