KR101605856B1 - apparatus for treating heavymetal and acidic waste water using red mud - Google Patents

Abstract

The present invention relates to a heavy metal and acid wastewater treatment material using red mud, a method for producing the same, and a heavy metal and acid wastewater treatment apparatus using the same. More specifically, And a method for producing the same, and a heavy metal and acidic wastewater treatment apparatus using the same.
The heavy metal and acid wastewater treatment materials using red mud of the present invention are formed by molding a mixture of red mud and cement.

Description

[0001] The present invention relates to an apparatus for treating heavy metals and acid wastewater using red mud,

The present invention relates to a heavy metal and acid wastewater treatment material using red mud, a method for producing the same, and a heavy metal and acid wastewater treatment apparatus using the same. More specifically, And a method for producing the same, and a heavy metal and acidic wastewater treatment apparatus using the same.

There are 2,500 large and small mines, including over 900 metal mines, 380 coal mines and 1,200 non-metal mines. About 80% of these mines are recreated or abandoned mines, The surrounding ecosystem is threatened because it is not installed.

Especially in waste metal mines, the mining waste (lignite, minerals, ore minerals) discharged from mining activities such as past mining and smelting processes are left in the vicinity of the mine and are dispersed downward by intensive rainfall or strong wind, Of agricultural land, water and environmental pollution.

At present, in the abandoned mine, the facility to prevent waste water (AMD (Acid Mine Drainage or ARD: Acid Rock Drainage) flowing out of the mine is not operated or the facilities for prevention are insufficient. Pollution problems are becoming serious. In addition to abandoned coal mines, current coal mines are being abandoned due to worsening profitability and decreasing demand of coal. These mine wastewater discharges harmful substances such as sulphates into rivers while releasing heavy metals into the surrounding soil, It is recognized as a major cause of contamination of waterworks, ground water, and soil, such as generating sediments.

Mineral wastewater is acidic with pH of 2 ~ 3 and contains sulfide mineral and Fe, Cd. Mn, Cu, and Pb. These heavy metals accumulate not only in the destruction of natural ecosystems but also in the human body, causing various diseases such as nervous system disorders, muscle paralysis, and bone related diseases.

In addition to mine wastewater, acid wastewater from various industrial sites also has problems such as environmental pollution, destruction of ecosystem, and causing various diseases.

To solve these problems, various techniques for treating acidic wastewater have been developed.

Korean Patent Registration No. 10-1254714 discloses a porous ceramic for treating acid wastewater using starfish, a method for producing the same, and an acidic wastewater treatment apparatus. The patent discloses a method of neutralizing acidic wastewater by using a ball-shaped ceramic which is formed by mixing 50 to 150 parts by weight of zeolite with 10 to 40 parts by weight of zeolite and 10 to 40 parts by weight of zeolite with respect to 100 parts by weight of starfish powder, .

Korean Patent Registration No. 10-1151772 discloses a heavy metal removal agent for acid wastewater using slag from a steel slag.

The above patent treats the heavy metals of the acid wastewater using a remover comprising zeolite and zirconium slag mixed in a weight ratio of 1: 1 to 3 and calcined at a temperature of 500 ° C to 800 ° C.

However, the above-mentioned patents have a problem that since the effect of removing heavy metals is low and they are produced by firing at a high temperature, a large amount of energy is consumed, which is not economical and requires a separate firing facility.

On the other hand, red mud means the sludge remaining after extracting aluminum hydroxide by the Bayer method (a method of extracting aluminum hydroxide by adding sodium hydroxide to a raw mineral containing a large amount of alumina) from bauxite raw mineral , Which is a red fine powder having a size of 5 to 20 μm and is generated in a slurry form (paste form) having a water content of about 30%.

Red mud is sludge-forming all over the world at an annual output of 120 million tons and dry powder at more than 40 million tons, and the amount is increasing every year. In Korea, annual sludge red mud is discharged at 200,000 tons. However, there is no way to treat red mud itself, and thus it is not only limited to building materials but also has no fundamental treatment. In particular, Red Mud is not suitable for the loading place worldwide, and it causes many environmental problems such as leakage of leachate and damage to nearby crops and human life. Therefore, Red Mud is in urgent need of treatment.

1. Korean Registered Patent No. 10-1254714: Porous Ceramic for Acidic Wastewater Treatment Using Starfish, Process for Producing the Same, and Acidic Wastewater Treatment Device 2. Korean Registered Patent No. 10-1151772: Removal of Heavy Metals from Acid Wastewater Using Slag of Stir-Fired Furnace

The present invention has been made in order to solve the above problems, and it is an object of the present invention to utilize red mud which is a strong basic wastes as a useful resource and to mix with cement and form it into a certain shape so that it can be cured without sintering, And an object of the present invention is to provide a treatment material having an excellent effect on treatment, a method for producing the same, and a heavy metal and acidic wastewater treatment apparatus using the same.

In order to attain the above object, the heavy metal and acid wastewater treatment material using red mud of the present invention is characterized by molding and curing a mixture of red mud and cement.

The mixture is mixed with 40 to 90% by weight of the red mud and 10 to 60% by weight of the cement.

Olivine powder or fly ash is added to the mixture.

In order to accomplish the above object, the present invention provides a method for producing heavy metals and acid wastewater using red mud, comprising: mixing 40 to 90% by weight of red mud and 10 to 60% by weight of cement; A molding step of molding a mixture of the red mud and the cement; And a curing step of drying and curing the molded body obtained in the molding step.

The mixing step is characterized in that 2 to 8 parts by weight of fly ash is added to 100 parts by weight of the mixture of the red mud and the cement.

In order to accomplish the above object, the present invention provides a heavy metal and acidic wastewater treatment apparatus using red mud, comprising: a retention tank in which acidic wastewater containing heavy metals stays and a conical bottom is formed; And a water treatment module installed inside the retention tank and contacting a ball-like treatment material with the acidic wastewater to remove heavy metals of the acidic wastewater and reduce the acidity of the treatment wastewater, wherein the treatment material includes red mud and cement Is molded and cured.

Wherein the water treatment module includes a cylindrical casing spaced upward from the bottom of the retention tank and formed in a mesh structure for allowing the acidic wastewater to pass therethrough and having a plurality of processing materials therein, A first rotating shaft which is rotatably supported in the retention tank through one side wall of the retention tank and is coupled to the first engaging panel; A second rotation shaft having a hollow structure coupled to the second engagement panel and rotatably supported through the other side wall of the retention tank and connected to the first rotation shaft to rotate the first rotation shaft, A reverse water conveyance pipe passing through the hollow portion of the second rotation shaft and extending horizontally from the outside of the staying tank to the inside of the casing; A backwash nozzle provided on an outer surface of the backwash water conveying pipe in a direction crossing the backwash water conveying pipe and having a flow path connected to a flow path provided inside the reverse waterwheel conveying pipe, An intervening collar formed in the casing for interfering with the processing material moving during rotation of the casing and a counter station for supplying backwash water to the washing water conveyance pipe and spraying backwash water into the casing through the backwash nozzle, And a wash water supply unit.

As described above, the present invention is excellent in the treatment of heavy metals and acid wastewater.

Further, the present invention can utilize red mud which is a strong basicidal waste as a useful resource in the water treatment field.

Also, since red mud and cement are mixed and molded into a certain shape, curing can be performed without firing, which makes it possible to economize and simplify the manufacturing facility.

FIG. 1 is a view showing an example of the manufactured treatment material,
2 to 9 are graphs showing the results of water treatment of acidic wastewater in a batch reactor,
10 to 17 are graphs showing the results of water treatment of acidic wastewater in a continuous flow reactor,
18 is a schematic configuration diagram of a heavy metal and acidic wastewater treatment apparatus according to an embodiment of the present invention,
19 is a schematic configuration diagram of a heavy metal and acidic wastewater treatment apparatus according to another embodiment of the present invention,
20 is a perspective view illustrating an example of a main portion applied to a heavy metal and acidic wastewater treatment apparatus according to another embodiment of the present invention.

Hereinafter, heavy metal and acidic wastewater treatment materials using red mud according to a preferred embodiment of the present invention, a method for producing the same, and heavy metal and acid wastewater treatment devices using the same will be described in detail.

The heavy metal and the acid wastewater treatment material of the present invention use red mud and cement as materials.

Red mud refers to the sludge remaining after extracting aluminum from bauxite raw material minerals. It may be a slurry form having a moisture content of about 30% or may be dried and powdered.

The cement may use conventional Portland cement. Cement serves as a binder and makes it possible to produce a treatment material of high strength without firing. In addition, since the cement itself is an alkaline substance, it contributes to the neutralization of the acidic wastewater, thereby helping to release the heavy metals in the acidic wastewater.

As an example of the present invention, heavy metals and acid wastewater treatment materials are formed by molding and curing a mixture of red mud and cement. For example, a mixture obtained by mixing 40 to 90% by weight of Red Mud and 10 to 60% by weight of cement is formed into a predetermined shape and cured.

If the content of red mud is less than 40% by weight, the effect of treating heavy metals and acidic wastewater is low. If the content of red mud exceeds 90% by weight, the formability and strength are lowered, and the treated material may be decomposed.

Red mud and cement are mixed at a certain ratio and stirred to evenly mix. It is of course possible to add water in an appropriate amount depending on the water content of the red mud. For example, when red mud powder is used, 5 to 30 parts by weight of water may be added to 100 parts by weight of a mixture of red mud and cement.

A mixture of mixed red mud and cement is molded into a uniform shape. The shape of the molded body can be molded into various shapes and sizes such as spherical, pellet, polygonal, and elliptical shapes. Molding can be performed by injecting a mixture into a mold or molding in a large amount using a molding machine.

After molding, the molded body is cured. Natural drying methods can be used as curing methods. For example, it is cured by natural drying for about 2 to 10 days. It is needless to say that the molded body can be cured by a conventional method of curing concrete.

The heavy metal and the acidic wastewater treatment material of the present invention are in contact with acidic wastewater to remove various heavy metals such as arsenic, cadmium, copper, iron, manganese, lead and zinc contained in the acidic wastewater, To neutralize the acid wastewater. Here, acid wastewater mainly refers to acidic mine drainage or acid industrial wastewater.

The pH of the acidic wastewater is increased by the strong alkaline component of the treated material, thereby removing the dissolved heavy metals in the acidic wastewater. Red mud contained in the treatment material is effective for stabilization of cadmium, lead and zinc, and can be used for coprecipitation with Al, Fe oxides present in red mud, or specific inner-sphere complexes with ligands existing in the oxide, The heavy metals are removed by formation.

Meanwhile, the heavy metal and acid wastewater treatment material according to another embodiment of the present invention contains red mud, cement, and olivine. For example, olivine powder is added to a mixture of red mud and cement, followed by molding and curing to produce a treating material.

2 to 8 parts by weight of olivin powder may be added to 100 parts by weight of a mixture of red mud and cement. Olivine imparts alkalinity and functions to purify water quality.

Further, the heavy metal and the acid wastewater treatment material according to another embodiment of the present invention contains red mud, cement, and fly ash. For example, fly ash is added to a mixture of red mud and cement, followed by molding and curing to produce a treating material.

2 to 8 parts by weight of fly ash may be added to 100 parts by weight of a mixture of red mud and cement.

Fly ash is a fly ash of fine powder produced in a power plant using bituminous coal, which imparts alkalinity and improves the durability by increasing the molding strength of the treatment material.

Hereinafter, the heavy metal and acidic wastewater treatment apparatus using the heavy metal and the acidic wastewater treatment material using red mud described above with reference to Fig. 1 will be described.

The acidic wastewater treatment apparatus of the present invention includes, for example, a retention tank (10) and a treatment material (30)

The acidic wastewater flowing through the flow rate adjusting tank 5 flows into the holding tank 10 through the inlet pipe. The acidic wastewater flows into the retention tank 10 through the pump 7 provided inside the flow rate adjusting tank 5. The flow rate adjusting tank 5 is supplied with acidic wastewater generated from an acidic wastewater generating source. Acidic wastewater is approximately 2 to 4 in pH and contains various heavy metals such as arsenic, cadmium, copper, iron, manganese, lead and zinc.

The retention tank (10) is formed in a cylindrical shape with an empty interior. A conical sinking part 50 is formed in the lower part of the holding tank 10. A drain pipe (66) for cleaning is installed in the settling portion (50).

The holding tank (10) has a structure divided into three regions. For example, the retention tank 10 includes an inlet 15 through which acidic wastewater flows, an accommodating portion 14 accommodating the treating material 30 into which the acidic wastewater that has passed through the inlet 15 flows, 14, the heavy metal is removed, the treated water whose acidity has been reduced is discharged and discharged to the outside, and the inflow portion, the receiving portion, and the discharge portion are sequentially formed from the retention bath front end.

The three regions of the inflow section 15, the accommodating section 14 and the discharge section 17 are divided by the first and second porous barrier ribs 20 and 25. The first and second porous barrier ribs 20 and 25 are formed with a plurality of through holes 23 and 27, respectively, through which fluid can pass. The size of each through hole is formed smaller than the size of the processing material (30).

A plurality of treatment materials 30 are accommodated between the first and second porous walls. In the illustrated example, the treatment material 30 is formed into a spherical ball shape. The treatments are stacked on a support (40). The support body 40 supports the processing materials stacked on the upper side, one side of which is supported by the first porous barrier 20 and the other side of which is coupled with the second porous barrier 25. [ A plurality of through holes 45 are formed in the support 40 so as to pass the fluid but prevent the treatment material 30 from passing therethrough.

The acidic wastewater flowing through the flow rate adjusting tank 5 flows into the inlet 15 of the holding tank 10. The acidic wastewater flowing into the inlet 15 passes through the through hole 23 of the first porous barrier 20 and flows into the receiver 14. The treatment material 30 accommodated in the storage portion contacts the incoming acidic wastewater to supply the alkali to the acidic wastewater to reduce the acidity and remove heavy metals from the acidic wastewater.

The treated water in which the acidity is reduced by the treatment material while the heavy metals are removed from the treatment unit is passed through the through hole 27 of the second porous partition wall 25 and flows into the discharge unit 17. The treated water flowing into the discharge portion 17 is discharged to the outside through the treated water discharge pipe 70. The treated water discharge pipe is provided with a discharge water control valve 75 capable of opening and closing the pipeline. It is preferable that a pH measuring instrument 90 is installed in the discharge portion in order to measure the pH of the treated water flowing into the discharge portion 17.

As described above, stable treatment of heavy metals and acidic wastewater is possible by using the heavy metal and the acidic wastewater treatment apparatus of the present invention.

2 shows a heavy metal and acidic wastewater treatment apparatus according to another embodiment of the present invention.

Referring to FIG. 2, there is provided a retention tank 100 in which acidic wastewater containing a heavy metal of the present invention stays, and a water treatment module 110 installed inside the retention tank 100.

The heavy metal and acidic wastewater treatment apparatus shown in FIG. 2 has a structure capable of rotating the water treatment module 110 so that backwashing of the treatment material 30 is effectively performed. The sludge mixed with the precipitate and various foreign substances generated in the water treatment process may clog the pores between the treatment materials or may be coated on the surface of the treatment material, thereby greatly reducing the treatment efficiency. Therefore, it is preferable to remove the sludge or the sludge coated on the surface periodically between the pores of the treatment materials so that the water treatment efficiency is not reduced.

The holding tank 100 has a square tubular shape and a conical precipitating portion 103 is formed at a lower portion thereof. A drain pipe (105) is provided below the settling portion (103). The acidic wastewater flowing through the flow rate adjusting tank 5 flows into the holding tank 100 through the inlet pipe. Although not shown, an inlet pipe through which acidic wastewater flows and a discharge pipe through which treated water is discharged are installed in the holding tank.

The water treatment module 110 is installed inside the retention tank 100. A ball-shaped treatment material 30 is accommodated in the water treatment module 110. The treatment material is the same as that applied to the embodiment of Fig.

The water treatment module 110 includes a cylindrical casing 111, first and second coupling panels 120 and 125, first and second rotation shafts 130 and 135, a driving part 140, 150, a backwash nozzle 160, and a reverse water supply unit (not shown).

The casing (111) is installed so as to be spaced upward from the bottom of the holding tank (100). The casing (111) is installed at a position lower than the surface of the acidic wastewater staying in the holding tank and is installed so as to be immersed in the acidic wastewater. The casing 111 is formed in a net structure so that acidic wastewater can pass therethrough, and a large number of processing materials 30 are accommodated therein. The treatment material 30 is accommodated in the casing so as to occupy a volume of about 60 to 80% of the space inside the casing 111. [

The left and right side surfaces of the casing 111 are formed into a cylindrical shape having an open structure. The first and second coupling panels 120 and 125 are respectively coupled to left and right open sides of the casing.

The first joining panel 120 is coupled to one side of the casing 111 and the second joining panel 125 is coupled to the other side of the casing 111. The first and second coupling panels 120 and 125 are disk-shaped.

The first rotation shaft 130 passes through one side wall of the retention tank 100 and is rotatably supported by the retention tank 100. One end of the first rotation shaft 130 is exposed to the outside of the retention tank and the other end is inserted into the retention tank and is coupled to the first engagement panel 120.

The second rotation shaft 135 passes through the other side wall of the retention tank 100 and is rotatably supported by the retention tank. One end of the second rotation shaft 135 is exposed to the outside of the retention tank and the other end is inserted into the retention tank and is coupled to the second engagement panel 125.

The driving unit 140 is connected to the first rotating shaft 130 to rotate the first rotating shaft to rotate the casing 111 during backwashing. The driving unit includes a motor 141 and a power transmitting means for connecting the driving shaft of the motor 141 and the first rotating shaft 130. As one example of the power transmission means, a first sprocket 143 coupled to a drive shaft of a motor, a second sprocket 145 coupled to the first rotation shaft 130, a first sprocket 145 coupled to the first sprocket 130, And a chain 147 for connecting the platts. Alternatively, it may be a pulley and a belt structure.

The reverse water conveyance pipe 150 extends horizontally through the center of the second rotation shaft 135 and into the casing 111 from the outside of the holding tank 100. For this purpose, the second rotation shaft 135 is made of a hollow structure. Since the reverse water storage conduit 150 inserted into the hollow of the second rotation shaft 135 is integrated with the second rotation shaft 135, the reverse water storage conduit 150 also rotates when the casing 111 rotates.

Therefore, a reverse water supply pipe (not shown) for introducing the reverse water for backwashing into the reverse water supply pipe 150 is connected to the reverse water supply pipe by a conventional rotary joint. The rotary joint connects the stationary retrofit pipeline and the rotating retrofit pipeline, allowing the backwash to move from the retrofit pipeline to the retrofit pipeline.

Although not shown, the backwash water supply section is composed of a tank storing backwash water, a backwash water supply pipe connecting the tank and the backwash water pipe, and a pump installed in the backwash water supply pipe to pump backwash water.

In the inside of the reverse water conveying pipe (150), a passage is formed inside so that backwash water can be transferred. A plurality of bar-shaped backwash nozzles 160 are installed on the outer surface of the reverse water conveying pipe 150. The backwashing nozzle 160 protrudes in a direction intersecting with the reverse water conveying pipe 150. The backwashing nozzle 160 is formed with a flow passage through which backwash water can flow. The flow path formed in the backwash nozzle 160 is connected to a flow path provided inside the reverse water conveyance pipe 150.

A plurality of ejection holes 155 and 165 are formed in the reverse water conveyance pipe 150 and the backwash nozzle 160. Therefore, the backwash water supplied to the reverse osmosis water conveyance pipe 150 is ejected into the casing 111 through the ejection holes formed in the reverse osmosis water conveyance pipe and the backwash nozzle. The reverse water supply unit supplies reverse osmosis water to the reverse osmosis water pipe, and discharges the reverse osmosis water into the casing to backwash the treatment material (30).

The heavy metal and acidic wastewater treatment apparatus of FIG. 2 described above can easily backwash the treatment material 30 and has a high effect of backwashing. That is, when backwashing is required, the acidic wastewater in the retention tank is discharged, and the driving unit 140 is operated to rotate the casing 111 to operate the pump of the reverse water supply unit. The backwash water supplied by the pump is strongly blown into the casing through the backwash nozzle 160 and the reverse water conveyance pipe 150. Due to the rotation of the casing 111 during backwashing, the treatment materials continuously flow through the inside of the casing 111, and thus the contact efficiency between the wash water and the treatment material is high. Therefore, the sludge trapped between the pores of the treatment materials and the sludge coated on the surface of the treatment material are easily desorbed. The desorbed sludge settles to the settling portion 103 and opens the valve of the drain pipe 105 to discharge the sludge to the outside.

3, an interference fringe 170 may protrude from the outer surface of the backwash nozzle 160 to enhance the contact effect between the treatment materials during backwashing of the treatment material to enhance the sludge desorption effect. The interference fringe 170 is formed to be twisted spirally on the outer surface of the backwash nozzle 160 to enhance the interference with the treatment material. The interference fingers are provided on the left and right sides of the backwashing nozzle 160 in pairs. The width of the interference fringe 170 is gradually wider as the upper portion is wider and the lower portion thereof is advanced.

Hereinafter, the present invention will be described with reference to experimental examples. However, the following experimental examples are intended to illustrate the present invention in detail, and the scope of the present invention is not limited to the following experimental examples.

<Water Treatment Experiment>

1. Batch reaction experiment

20 parts by weight of water was added to 100 parts by weight of a mixture of powdered red mud (KC Co., Ltd., Korea) and Portland cement (Tong Yang Cement, Korea) and the mixture was stirred. After mixing, the kneaded material was shaped into a ball shape and then dried naturally for 5 days to prepare a spherical treatment material having a diameter of about 1 to 2 cm. The total weight of the mixture of red mud and cement was 6 kinds according to the weight of red mud (40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt% and 90 wt%) . The state of the manufactured treatment material is shown in Fig.

The pH of the red mud used in the experiment was about 11.5 and consisted of 45.48 wt% of Fe ₂ O ₃ , 13.27 wt% of SiO ₂ , 16.15 wt% of Al ₂ O ₃ , 10.46 wt% of TiO ₂ , 0.06 wt% of MnO, 0.34% by weight of MgO, 0.27% by weight of K ₂ O, 5.89% by weight of Na ₂ O and 0.39% by weight of P ₂ O ₅ .

The treated material was filled in a 1 L batch reactor at a volume of 5% and then 900 mL of acidic wastewater containing heavy metals was injected and reacted for a certain period of time (30, 60, 90, 120, 240 min) The pH and the contents of heavy metals were analyzed in comparison with the initial values before the reaction. Al, As, Cd, Cu, Fe, Mn, Pb and Zn were analyzed as heavy metals.

The results of the pH analysis of the acidic wastewater according to the kind of the treating material are shown in Table 1 below.

division pH Early 2.89 R40-240 12.25 R40-120 11.95 R40-90 11.67 R40-60 9.08 R40-30 4.57 R50-240 12.16 R50-120 11.68 R50-90 11.35 R50-60 7.65 R50-30 4.47 R60-240 12.05 R60-120 11.73 R60-90 11.05 R60-60 6.25 R60-30 4.5 R70-240 11.93 R70-120 11.27 R70-90 10.29 R70-60 6.04 R70-30 4.02 R80-240 11.24 R80-120 9.78 R80-90 9.57 R80-60 5.13 R80-30 3.9 R90-240 10.61 R90-120 9.4 R90-90 8.37 R90-60 7.47 R90-30 3.8

 &Quot; R40 "in" R40-240 " in Table 1 means a treatment material in which 40% by weight of red mud is mixed, and 240 means that the reaction time is 240 minutes. Therefore, R50, R60, R70, R80 and R90 respectively mean treatment materials in which 50% by weight, 60% by weight, 70% by weight, 80% by weight and 90% by weight of red mud are mixed. And -120, -90, -60, and -30 mean reaction times of 120 minutes, 90 minutes, 60 minutes, and 30 minutes, respectively. The same is applied hereinafter.

As shown in Table 1, the initial pH of the raw water before the reaction was 2.89. As the reaction time of raw water treatment was longer, the pH was higher. Especially, the reaction time is 60-120 minutes, and it is appropriate that the reaction time is 60-120 minutes depending on the content of red mud.

When the content of red mud increased during the same time reaction, it was confirmed that the pH was increased partly but decreased partly. Since the pH of the cement is 12.5, which is higher than the red mud pH of 11.5, the content of cement is lowered as the content of red mud increases, and it is presumed that the pH is changed according to the mixing ratio of red mud and cement.

The concentration (ppm) of heavy metals and the removal efficiency (%) of heavy metals according to the six kinds of treatment materials are shown in FIG. 2 to FIG. 9, respectively. The removal efficiency of heavy metals was calculated as {(initial concentration - concentration after reaction) / initial concentration} × 100.

The initial concentration (ppm), the maximum concentration (ppm) and the minimum concentration (ppm) of each heavy metal before the reaction and the maximum removal efficiency (%) and the minimum removal efficiency (% Respectively.

Item Initial concentration Maximum concentration Maximum removal efficiency Minimum concentration Minimum removal efficiency Al 45.75 42.56 99.69 0.14 6.97 As 6.12 0.36 100.00 0.00 94.12 CD 2.93 2.67 100.00 0.00 8.87 Cu 8.36 6.55 100.00 0.00 21.65 Fe 90.59 2.94 99.99 0.01 96.75 Mn 8.02 7.04 100.00 0.00 12.22 Pb 6.63 1.28 100.00 0.00 80.69 Zn 8.6 7.32 100.00 0.00 14.88

Referring to the results of FIGS. 2 to 9 and Table 2, although the removal characteristics were somewhat different according to the types of heavy metals, the removal efficiency of heavy metals was higher as the total red mud content was higher. It was confirmed that the maximum removal efficiency of heavy metals by the treatment material is 99 ~ 100% regardless of the kind of heavy metal. Especially, the removal efficiency of arsenic, iron, and lead was very good.

Batch reaction experiments showed that mixing ratio of red mud is 80 ~ 90 wt% and reaction time is 90 ~ 120 min, which is most suitable for acid wastewater treatment.

2. Continuous flow type reaction experiment

A continuous flow reactor was filled with a treatment material mixed with 80% by weight of Red Mud and subjected to a continuous reaction experiment. The acid wastewater was treated for 29 days while circulating the acid wastewater into the reactor at a flow rate of 1 ml per minute.

The experimental conditions are summarized in Table 3 below.

division   rd80-120-50 rd80-120-75 Processing re-filling volume (%) 50 75 Treatment Refill Weight (g) 180 270 Inflow of acid wastewater (ml / min) One One

Experimental results of treating materials containing 80% by weight of red mud are divided into two types according to the filling volume of the reactor. The concentration (ppm) of each heavy metal and the removal efficiency (%) of the heavy metal in the case of 50% and 75% filling volume of the treated material are shown in FIGS. 10 to 17, respectively. The removal efficiency of heavy metals was calculated as {(initial concentration - concentration after reaction) / initial concentration} × 100.

Referring to FIG. 10, the average concentration of aluminum was 4.21 ppm and the average removal efficiency was 90.80% when the filling volume of the treatment material was 75% (rd80-120-75, the same applies hereinafter). The average concentration of aluminum was 6.27ppm and the average removal efficiency was 86.30% when the filling volume of the treated material was 50% (rd80-120-50, the same applies below).

11, the average concentration of arsenic in rd80-120-75 was 0.51 ppm and the average removal efficiency was 91.73%. The average concentration of arsenic in rd80-120-50 was 0.82ppm and the average removal efficiency was 86.57%.

12, the average concentration of cadmium in rd80-120-75 was 0.18 ppm and the average removal efficiency was 93.72%. The average concentration of cadmium in rd80-120-50 was 0.402ppm and the average removal efficiency was 86.42%.

13, the average concentration of copper in rd80-120-75 was 1.03 ppm, and the average removal efficiency was 87.66%. The average concentration of copper in rd80-120-50 was 1.33 ppm and the average removal efficiency was 84.14%.

Referring to FIG. 14, in the case of rd80-120-75, the average iron concentration was 4.31 ppm and the average removal efficiency was 95.24%. In the case of rd80-120-50, the average iron concentration was 7.66ppm and the average removal efficiency was 91.55%.

Referring to FIG. 15, in the case of rd80-120-75, the average concentration of manganese was 0.63 ppm and the average removal efficiency was 92.14%. The average concentration of manganese in rd80-120-50 was 1.12ppm and the average removal efficiency was 85.99%.

Referring to FIG. 16, the average concentration of lead in rd80-120-75 was 0.65 ppm, and the average removal efficiency was 90.20%. The average concentration of lead in rd80-120-50 was 0.90ppm and the average removal efficiency was 86.40%.

17, the average concentration of zinc in rd80-120-75 was 0.73 ppm and the average removal efficiency was 91.47%. The average concentration of zinc in rd80-120-50 was 1.15ppm and the average removal efficiency was 86.67%.

11 to 17, the removal efficiency of rd80-120-75 was about 5% higher than that of rd80-120-50. And it was confirmed that it is possible to sufficiently remove various heavy metals by only one day processing time.

From the above experimental results, the present invention shows that neutralization of acid wastewater and removal of heavy metals are excellent using red mud and cement.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention. . Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

5: Flow control tank 10:
14: receiving portion 15: inlet portion
17: discharge part 30: treated material
50: Deposition part 110: Water treatment module
111: casing 140:

Claims (1)

A retention tank in which acidic wastewater containing heavy metals stays and a lower portion is conically formed;
And a water treatment module installed in the retention tank and contacting the ball-shaped treatment material with the acidic wastewater to remove heavy metals of the acidic wastewater and reduce acidity,
The treatment material is formed by molding a mixture of red mud and cement,
Wherein the water treatment module includes a cylindrical casing spaced upward from the bottom of the retention tank and formed in a mesh structure for allowing the acidic wastewater to pass therethrough and having a plurality of processing materials therein, A first rotating shaft which is rotatably supported in the retention tank through one side wall of the retention tank and is coupled to the first engaging panel; A second rotation shaft having a hollow structure coupled to the second engagement panel and rotatably supported through the other side wall of the retention tank and connected to the first rotation shaft to rotate the first rotation shaft, A reverse water conveyance pipe passing through the hollow portion of the second rotation shaft and extending horizontally from the outside of the staying tank to the inside of the casing; A backwash nozzle provided on an outer surface of the backwash water conveying pipe in a direction crossing the backwash water conveying pipe and having a flow path connected to a flow path provided inside the reverse waterwheel conveying pipe, An intervening collar formed in the casing to interfere with the processing material moving during rotation of the casing, and a backwash water supply unit for supplying backwash water to the backwash water conveying pipe to spray backwash water into the casing through the backwash nozzle, And a reverse water supply unit connected to the reverse water supply unit. The apparatus for treating heavy metals and acidic wastewater using red mud.

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