KR100851555B1 - METHOD FOR REMOVING SOx WITH BRUCITE SLURRY - Google Patents

Abstract

In accordance with the present invention, a method for removing sulfur oxides by a tailings slurry is disclosed. The method of the present invention comprises the steps of preparing a powder (Brucite), mixing the powder with water and obtaining water, and the step of contacting the tailings slurry with the flue gas containing sulfur oxides to remove the sulfur oxides from the flue gas It includes a step. The present invention provides a method for removing sulfur oxides by using a natural mineral Sumirite Slurry (Mg (OH) ₂ ), which can be used by the present invention. This can improve the economics of the desulfurization process. The present invention further provides the advantage of achieving an improved desulfurization efficiency by performing a desulfurization process using a tailings slurry.

Sumite stone, active stone, magnesium hydroxide, desulfurization, slurry, sulfur oxides, exhaust gas

Description

Sulfur oxide removal method by Sumi Kite slurry {METHOD FOR REMOVING SOx WITH BRUCITE SLURRY}

FIG. 1 is a graph of an X-ray diffraction pattern obtained by X-ray diffraction analysis on Sumite Stone A applied to an embodiment of the present invention.

FIG. 2 is a graph of an X-ray diffraction pattern obtained by X-ray diffraction analysis on a conventionally used hydrated magnesium hydroxide [Mg (OH) ₂ ].

Figure 3 is a graph obtained by thermal analysis (Thermal Gravimetric Analysis) for Sumirite A applied to an embodiment of the present invention.

Figure 4 is a graph obtained by performing a thermal analysis (Thermal Gravimetric Analysis) of a conventionally used hydrated magnesium hydroxide [Mg (OH) ₂ ].

FIG. 5 is a schematic diagram of a laboratory-scale small reactor fabricated for experiments on the desulfurization performance of a tartar slurry in embodiments of the present invention.

The present invention relates to a method for removing sulfur oxides by a tailings slurry, and more particularly, by using a structurally and thermally stable tailings slurry to perform the desulfurization process at a higher temperature than a conventional desulfurization process. The present invention relates to a method for removing sulfur oxides by using a tailings slurry that can improve the economics of a desulfurization process.

As a method of removing sulfur oxide (SOx), which is a flue gas pollutant, a wet flue gas desulfurization device, a gypsum-lime method, a caustic soda method, and the like are mainly used. However, the gypsum-lime method has a limitation in application because the cost of limestone, which is a raw material, is low, and the size of the apparatus is required to increase the installation cost, and the treatment of by-product gypsum affects economic efficiency. Caustic soda method has the advantage that it can be treated as a small device, but has a problem that the drug price is expensive and difficult to handle.

On the other hand, wet flue gas desulfurization apparatus using magnesium hydroxide has been evaluated as economical because it has high efficiency in removing flue gas and removing harmful gases. Magnesium hydroxide used in wet flue gas desulfurization is conventionally prepared by pulverizing light magnesium obtained from magnesite and mixing with water to raise the temperature above normal pressure to hydrate magnesium oxide in light magnesium. However, this manufacturing method has a problem that it takes a long time to obtain a high hydration rate and low productivity, and also has a problem of high energy cost because magnesite, a raw mineral, has to be calcined with high heat to obtain light magnesium.

On the other hand, Brucite is a natural mineral of magnesium hydroxide, also called hydrite. It can be considered that such a tailing stone can be used in the desulfurization process in place of magnesium hydroxide prepared by hydration of light magnesium, but there have been no reports of the use of the tailing stone in the desulfurization process.

The inventors of the present invention suggest that there are no examples of the use of Sumi-seok in the desulfurization process, and that the Sumi-seok is inefficient in the conditions of the general desulfurization process or other unsuitable factors. A study has been conducted that has found that the tailingsite has the same structure as magnesium hydroxide prepared by hydration of small and medium magnesia, but is more stable in terms of structural and thermal aspects microscopically. The present invention has been realized by recognizing that a tailing stone can be used in a desulfurization process.

Accordingly, it is an object of the present invention to provide a method for removing sulfur oxides from flue gas by using a tailing stone in a desulfurization process that has not been considered industrially available in a desulfurization process.

It is also an object of the present invention to provide a structurally and thermally stable slurry of Sumite stones for use in gastric desulfurization processes.

Other objects and advantages of the invention will be set forth more clearly in the description that follows.

The present invention provides a method for removing sulfur oxides by using a tailings slurry. The method of the present invention comprises the steps of preparing a brucite powder, mixing the taste powder and water to obtain a taste stone slurry and contacting the taste stone slurry with a flue gas containing sulfur oxides to remove sulfur oxides from the flue gas. It includes a step.

Sumirite powder used in the present invention is the temperature of the highest thermal decomposition rate in the first major weight loss area when the thermal analysis (Thermal Gravimetric Analysis; TGA) while heating at a rate of 5 ℃ / min in a nitrogen atmosphere is 423 ± It is characterized in that the 25 ℃, the temperature of the highest thermal decomposition rate in the second major weight reduction region is 708 ± 30 ℃, and the (0,0,1) peak in the X-ray diffraction pattern ( 1,0,1) It is stronger than the peak. The concentration of tailings in the tailings slurry in the desulfurization process is preferably 20 to 50%. In addition, the wet desulfurization reaction of removing the sulfur oxides by contacting the tailings slurry with the flue gas containing the sulfur oxides is preferably performed at a temperature of the wet reactor, that is, the temperature of the circulating water is 55 to 75 ° C. The slurry is preferably activated in a temperature range of 70 ~ 150 ℃ under pressure above atmospheric pressure.

In another aspect, the present invention is to provide a millite slurry that can be used in the desulfurization process as described above.

Hereinafter, the present invention will be described in more detail.

The present invention provides sulfur oxides (SOx) from exhaust gas by contacting a tailings slurry formed by mixing the tailings powder obtained by screening, coarse and fine grinding of the raw stones collected from the tailings mineral mine with water and the exhaust gas of power plant, boiler, etc. It is about how to remove. Sumite stone used in the present invention is a natural mineral of magnesium hydroxide [Mg (OH) ₂ ], and the same chemical formula and crystals as magnesium hydroxide (hereinafter referred to as "hydrated magnesium hydroxide") formed by hydrating light magnesium (MgO) Since it is known to have a structure, it can be expected to be used in the desulfurization process in place of hydrated magnesium hydroxide. However, to the knowledge of the present inventors, there have been no examples of applying the Sumitomeite to the desulfurization process industrially so far, and there is no report on the experimental applicability. From this situation, those of ordinary skill in the field of the present invention can be assumed that the Sumite stone is not applicable to the desulfurization process, or even economically impossible to use industrially because it is not economical.

However, in spite of this recognition, the inventors have repeatedly studied the desulfurization process by the structure of Sumirite and the Slurry Slurry in order to find the conditions under which the Sumirite is applicable to the desulfurization process. Has the same structure as hydrated magnesium hydroxide, but has different microstructures and the resulting thermal properties are different. That is, it has been recognized that the sumite stones have more structural and thermal stability than hydrated magnesium hydroxide, as described in detail below. Thus, the present invention preferably targets a tailing stone having such structural and thermal stability. On the basis of this recognition, the present inventors have found that if the desulfurization process is performed at a higher temperature or if the calcite slurry is activated by a separate activation process, the scotch slurry has better efficiency than the conventional hydrated magnesium hydroxide. The present invention has been reached.

X-ray diffraction analysis of the structure of the tailing stone used in the present invention shows that the tailing stone is the same as the hydrated magnesium hydroxide in that it has a plate-like structure as a mineral of a hexagonal structure. Sumite stone differs from hydrated magnesium hydroxide in terms of microstructure in that the unit cell parameter of the crystal is almost the same as the standard value, while the hydrated magnesium hydroxide is somewhat different. In hydrated magnesium hydroxide, unhydrated MgO acts as a crystal defect and undecomposed micro MgCO ₃ remains during the pyrolysis of magnesite, resulting in incomplete crystal structure. Not only can it have a perfect crystal structure, but even if there are other impurity components, it is presumed to have a more stable structure by forming a crystal structure by natural force for a long time. However, since the difference in the unit lattice constant may vary depending on the state of the summit stone, that is, the presence of impurities, the degree of hydration, it may be difficult to directly connect the difference of the unit lattice constant with the features of the present invention. However, a little macroscopically, the summit stone is shown in FIG. 1, while the intensity of the (0,0,1) peak is greater than that of the (1,0,1) peak, while the hydrated magnesium hydroxide is As can be seen, the opposite is in line with the features of the present invention. This difference in XRD peak intensity is an important factor in characterizing the Sumite stone as having different physicochemical properties from the conventional hydrated Mg (OH) ₂ . This structural difference is also consistent with the results of SEM and IR analysis. Therefore, the present invention is characterized by using the structurally stable Sumite and Sumite slurry in the desulfurization process.

On the other hand, hydrated magnesium hydroxide is obtained by hydrating light magnesium (MgO) obtained by calcining magnesite, and the tailing stone is hydrated in a natural state. This hydration not only affects the crystal structure but also the thermal properties. As a result of performing a thermal analysis (TGA) according to the following example, as shown in Figure 3, the sumite stone is reduced by the evaporation of the evaporation component at about 423 ° C and about 708 ° C, respectively Temperature at the highest pyrolysis rate at 29.3% and 2.4%, respectively, and the total weight loss in the entire temperature range from room temperature to 950 was 32.9%), whereas the hydrated magnesium hydroxide weight loss at about 378 ° C and 637 ° C, respectively. 28.0% and 2.4%; total weight loss over the entire temperature range from room temperature to 950 was 30.4%). This weight loss is mainly due to the evaporation of hydroxy groups of Mg (OH) ₂ to H ₂ O by pyrolysis. Due to the fact that the weight loss is higher at the higher temperature than the hydrated magnesium hydroxide, it is thermally more stable than the hydrated magnesium hydroxide. This is in accord with the above fact that Sumi-seok is structurally stable. Therefore, the present invention is characterized by using the structurally and thermally stable Sumite and Sumite slurry in the desulfurization process. From this fact, the present invention shows that when thermal analysis is carried out under the same conditions as in the examples, the temperatures with the highest thermal decomposition rate in the main weight reduction area are 423 ± 25 ° C (primary) and 708 ± 30 ° C (secondary). Suminium stone characterized by the characteristics can be used in accordance with the object of the present invention. The temperature at which the pyrolysis rate is the highest in the main weight reduction area of the tailings stone is a temperature capable of characterizing the tailings stone of the present invention which can be clearly distinguished from that of hydrated magnesium hydroxide. The temperature at which the highest pyrolysis rate in the major weight loss zones used is the highest pyrolysis rate temperature for the weight loss zone, which is characteristic of a small weight loss, which is the curve of-(dm / dt) versus temperature [ Where m is the weight to be reduced and t is the temperature], i.e., the temperature at the highest value of the DTG curve (Derivative Thermogravimetric Curve) will be readily understood with reference to FIGS.

In the present invention, as a result of injecting the tailings slurry formed by mixing the tailings powder with water in the experimental desulfurization process, the tailings slurry is sulfuric acid than the hydrous magnesium hydroxide at 40 ℃ as the temperature of the wet desulfurization reactor, that is, the temperature of the circulating water While the cargo removal performance was inferior, it was excellent above 60 ° C. Typically, the wet desulfurization process in power plants, boilers, etc. is carried out at a temperature of 40 ~ 50 ℃ of the circulating water. It is presumed that this is due to the recognition that desulfurization by the tailings slurry in the past has not been applied industrially and is not usable. However, the present invention has been found that the desulfurization performance is not high at low desulfurization temperature due to the structural and thermal stability, but the desulfurization performance is superior to the hydrated magnesium hydroxide at a temperature higher than the temperature at which the calcite can be activated. Accordingly, the present invention is preferably characterized in that the tailings slurry is applied to a desulfurization step at a temperature of 55 ° C. or higher, preferably 55 to 75 ° C. Although the sumite stone of the present invention is expected to be activated for the desulfurization process even at a temperature of 80 ° C. or higher, it is difficult to control the process due to the evaporation of water and has a disadvantage in that economic efficiency is high due to high water consumption. In addition, it is expected that the use of the slurry of the characteristic tailings used in the present invention can achieve desulfurization performance equivalent to that of the conventional hydrated magnesium hydroxide even at a temperature of about 50 ° C. of the conventional desulfurization process. In particular, if the optimization of the tailings slurry and the optimization of the process conditions is carried out such a desulfurization process can be easily achieved with the tailings slurry of the present invention. In the present specification, the temperature of the wet desulfurization process means the temperature of the circulating water of the wet desulfurization reactor.

On the other hand, in addition to increasing the temperature of the desulfurization process for the activation of the tailings slurry of the present invention, it is possible to perform a separate activation process in the temperature range of 70 ~ 150 ℃ under pressure above atmospheric pressure. Activation of such a tailings slurry is proposed based on the structural and thermal stability of the tailingsstone, and structurally destabilizes the tailingsstone to improve the reactivity of the desulfurization reaction. Accordingly, the present invention also provides a tailings slurry, particularly activated tailings slurry, as applicable to the desulfurization process. In the present invention, it is preferable that the tailings slurry in the desulfurization process has a tailings concentration of 20 to 50%. If the concentration of tailings is too low, the transportation cost is high and the amount of slurry added is high, and if it is too high, handling becomes difficult.

On the other hand, in order to improve the desulfurization performance or other required performance of the tailings slurry in the present invention, a surfactant, an alkali substance such as NaOH, or the like may be added to the tailings slurry. Additives that can be added in the present invention are not particularly limited as long as they do not inhibit the activity of the tailingsstone and include all additives that can be added for desulfurization or other desired performance enhancement.

Hereinafter, the present invention will be described by specific examples. However, the following embodiments are only intended to describe the present invention, it will be apparent to those of ordinary skill in the art that the scope of the present invention should not be understood to be limited to these embodiments. will be.

Example

In the present embodiment, component analysis, structural analysis, and thermal analysis were performed on the calcite and the hydrated magnesium hydroxide as a comparative example, and the desulfurization performance was evaluated according to the SOx concentration, the desulfurization reaction temperature, and the particle size of the calcite. The desulfurization performance of the tailings slurry activated by the process was also evaluated.

Mg ( OH ) ₂ Slurry  Produce

In order to prepare the tailings slurry, the raw stones were collected from the tailings mine, sorted, crushed, and then milled back into fine particles. Here, the crushed millite raw material was prepared in a slurry of 30 to 35% concentration to obtain a millite slurry.

On the other hand, in order to obtain hydrated magnesium hydroxide, ore was collected from MgCO ₃ (magnesite) mine, coarsely pulverized, put in a furnace, heated to 700 ° C. or more, and thermally decomposed MgCO ₃ to blow CO ₂ to prepare MgO. MgO prepared here is sorted to remove impurities and then finely pulverized 325 mesh using a Raymond mill or the like is used as a raw material. The MgO raw material prepared here is first slurried in water at a concentration of about 40-50%, and then put into a reactor at 100 ° C. or higher to be hydrated to form Mg (OH) ₂ . 50%) of hydrated magnesium hydroxide slurry is prepared.

Physical / chemical characterization of raw materials

Sumistone sample-The sumiolite prepared in the same way as above was purchased from 325 mesh and 5,000 mesh in China A company, and then they were dried for 1 day in an oven at 110 ℃ was used as a sample.

Hydrated Mg (OH) ₂ Sample-The Mg (OH) ₂ slurry prepared in the above manner was purchased from K in Korea, and water was removed by vacuum filtration, followed by drying for 1 day at 110 ° C. Oven to be used as a sample. . However, as the particle size analysis sample, 35% Mg (OH) ₂ slurry was used as it is.

Chemical analysis was performed using Leeman's Prodigy Spectrometer using ICP (Inductively Coupled Plasma) method. Particle analysis was performed by flowing N ₂ gas using Malvern's Mastersize Micro instrument. Powder X-ray diffraction pattern (Powder X-ray Diffraction pattern) uses a Ni filter, Cu-Kα ₁ Radiation (λ = 1.54060 Hz) using Panalytical's X'pert Pro equipment, with 2θ values ranging from 10 ° to 80 °. It was measured at a scanning speed of 1.2 ° / min in the range. SEM (Scanning Electron Microscope) was obtained from 1,000 times to 10,000 times magnified image in a vacuum using Hitachi S-3500N equipment. IR (Infrared) Spectra was obtained using KBr Pellet technology in the range of 4,000-500 cm ^-1 using a Bomem MB104 instrument equipped with a DTGS detector. TGA (Thermal Gravimetric Analysis) was measured in the range of 50 ~ 950 ℃ at a rate of 5 ℃ / min under N ₂ atmosphere using TA Instrument TGA2950 equipment.

Result of characterization of raw materials

Component Analysis

As a result of chemical analysis, MgO, the main component, was slightly lower in Sumirite A (93.96%) and hydrated Mg (OH) ₂ (94.87%). As the main impurities, Sumirite A showed 1.91% of CaO component and lower than 2.44% of Mg (OH) ₂ , while SiO _{2 contained} 3.65% of Sumiteite and 1.82% of Hydrated Mg (OH) _2. Was high. In the case of Sumite B, the MgO content was 94.95%, similar to the hydrated Mg (OH) ₂ , and the CaO and SiO ₂ components were 2.06% and 2.54%, respectively. Detailed analysis results are shown in Table 1 below.

division Item Sumistone A (325 mesh) Sumite Stone B (5,000 Mesh) Hydrated Mg (OH) ₂ Chemical composition (wt%) MgO 93.96 94.95 94.87 CaO 1.91 2.06 2.44 SiO ₂ 3.65 2.54 1.82 Al ₂ O ₃ 0.07 0.06 0.39 Fe ₂ O ₃ 0.41 0.38 0.48 Sum 100.00 100.00 100.00

Structural Analysis (X-ray diffraction  pattern)

이며, unit cell Dimension이 a=3.148Å, c=4.769Å으로 밝혀졌다. 수미석A의 X-선 회절 패턴에서는 도 1에서 보는 바와 같이, (0,0,1) 피크가 강한 세기를 나타내고 있는데 이는 판상의 구조가 매우 발달하였기 때문으로 사료된다. 수미석의 Cell parameter값이 표준값(a=3.147Å c=4.767Å)과 거의 일치하는 것을 보면 수미석이 완전하게 수화되어 단결정의 Mg(OH)₂ 구조를 가지는 것임을 알 수 있다. 다만, 이러한 단위 격자 상수들은 불순물의 함유 및 수화의 정도 등 수미석의 상태에 따라 달라질 수 있는 것이어서 곧바로 본 발명의 특징과 연결하기는 어렵지만, (0,0,1) 피크가 강한 세기를 가지는 수미석은 구조적 특성화를 제공하는 중요한 요소로서 본 발명의 특징과 연결할 수 있다. Analysis of X-ray diffraction pattern of Sumite Stone A showed hexagonal structure, Space group

The unit cell dimension was found to be a = 3.148 Å and c = 4.769 Å. In the X-ray diffraction pattern of Sumite Stone A, the (0,0,1) peak shows a strong intensity, as shown in FIG. 1, because the plate-like structure is very developed. It can be seen that the cell parameter value of Sumi-seok is almost identical to the standard value (a = 3.147Å c = 4.767Å) and the Sumi-stone is completely hydrated and has a single crystal Mg (OH) ₂ structure. However, these unit lattice constants may vary depending on the condition of the tailing stone, such as the impurity content and the degree of hydration, so that it is difficult to directly connect with the features of the present invention, but the (0,0,1) peak has a strong intensity. The tailings can be linked to the features of the present invention as an important factor in providing structural characterization.

이며, unit cell Dimension은 a=3.140Å, c=4.755Å으로 Mg(OH)₂ 구조와 일치하는 것으로 밝혀졌다. 하지만 수화 Mg(OH)₂의 Cell Demension이 Standard값(a=3.147Å, c=4.769Å)보다 작아졌는데, 이는 수화과정에서 MgO가 100% Mg(OH)₂로 수화되지 않고 일부 미수화상태로 존재하는 결함 사이트를 가지기 때문에 격자의 크기가 줄어든 것으로 사료된다. 수화Mg(OH)₂의 XRD 피크에서 불순물 피크들로 MgCO₃ 피크와 CaCO₃ 피크가 나타났다. 이중 MgCO₃ 피크는 광석을 분쇄 후 CO₂ 열분해 과정에서 분해되지 않는 미소(未燒) MgCO₃가 다량 있는 것으로 보여진다. CaCO₃ 피크는 표 1의 성분분석의 결과에서 보이는 바와 같이 CaO 성분 (2.44%)이 일부 존재하는 것에 기인한 것으로 보인다.X-ray diffraction pattern of hydrated Mg (OH) ₂ was analyzed.

The unit cell dimensions were found to be consistent with the Mg (OH) ₂ structure with a = 3.140 ms and c = 4.755 ms. However, the cell demension of hydrated Mg (OH) ₂ is smaller than the standard value (a = 3.147Å, c = 4.769Å), which means that the MgO is not hydrated to 100% Mg (OH) ₂ in some hydrated state. It is believed that the grid size is reduced because of the presence of defective sites. Impurity peaks in the XRD peak of hydrated Mg (OH) ₂ showed MgCO ₃ peak and CaCO ₃ peak. The double MgCO ₃ peak appears to have a large amount of micro MgCO ₃ that does not decompose during the CO ₂ pyrolysis process after the ore is crushed. The CaCO ₃ peak appears to be due to the presence of some CaO component (2.44%) as shown in the component analysis results in Table 1.

As shown in Figs. 1 and 2, the (0,0,1) peak shows a strong intensity in the Sumite stone X-ray diffraction pattern, whereas the hydrated Mg (OH) ₂ shows a strong intensity at the (1,0,1) peak. Indicated. This may be due to the result that the ordering of atoms in the c-axis is stronger in ordering than the hydrated Mg (OH) ₂ , and the lamellar structure is more developed than the hydrated Mg (OH) _2. It is shown. From these structural analysis data, the sumite stones used in the present invention can be said to be more structurally stable than the conventionally used hydrated Mg (OH) ₂ .

SEM  analysis

SEM image of Sumi-seok shows very plate-like structure. This is consistent with the strong intensity of the (0,0,1) peak of the summit stone, as analyzed in the XRD results. In the picture (not shown), the tailingsstone shows a very sharp shape, which appears to be irregularly broken as the interface is sharply broken by grinding during the preparation of the tailingsstone.

The hydrated Mg (OH) ₂ SEM image shows the same plate-like structure as that of the tailing stone. However, the lamellar structure is less developed than in the summit stone, which is consistent with the strong intensity of the (1,0,1) peak, as in the XRD results. In the SEM image, the hydrated Mg (OH) ₂ has rounded corners. The surface of the Mg (OH) ₂ was smoothly changed during the production of the hydrated Mg (OH) ₂ and during the MgCO ₃ pyrolysis and MgO hydration. do.

IR  analysis

The very strong absorption band of 3698 cm ^-1 in the FT-IR spectrum of the tailstone is the stretching vibration mode of the OH group attached to the inorganic lattice, and the strong broad band in the 3442 cm ^-1 region Stretching vibration mode of OH group. In addition, 1622cm ^{- 1} H ₂ O is a bending vibration mode (Bending Vibration mode), 1486cm ^{- 1} and the peak of 1424cm ^-1 were interpreted as the in-plane bending vibration mode (In-Plane Bending Vibration mode) of the OH group.

Hydrated Mg (OH) ₂ in the FT-IR spectra absorption bands of a very strong intensity of 3696cm ^-1 is OH stretching vibration mode attached to Inorganic Lattice, a strong broad band of 3441cm ^-1 is the OH stretching vibration mode. In addition, 1633cm ^{- 1} is the absorption band is a bending vibration mode of the H ₂ O ₂ is attached to the surface of Mg (OH). A strong broad band in the region of 1445 cm ⁻¹ appears to overlap the in-plane bending vibration mode of the OH group with the stretching vibration mode ν ₃ of CO ₃ . This is different from the in-plane bending mode of the OH group, which appears as two peaks in the tailings stone.

The absorption band of 876 cm ^-1 was interpreted as the CO ₃ stretching vibration mode (ν ₂ ). The CO ₃ stretching vibration peaks that do not appear in the Sumite stone IR spectrum are observed in the IR spectrum of hydrated Mg (OH) ₂ , which is consistent with the presence of MgCO ₃ and CaCO ₃ shown in hydrated Mg (OH) ₂ X-ray diffraction.

Thermal analysis Thermal Gravimetric Analysis )

Thermogram patterns of Sumite Stone A and Hydrated Mg (OH) ₂ are similar. As shown in Figure 3, Sumi-seok A showed weight loss of 29.3% near 423 ° C and 2.4% weight loss near 708 ° C. In hydrated Mg (OH) ₂ , as shown in FIG. 4, the weight loss was found to be 28.0% near 378 ° C., and 2.4% of the weight loss was found at 637 ° C. The total weight loss from room temperature to 950 ° C was 32.9% for Sumite Stone A and 30.4% for Hydrated Mg (OH) ₂ . In the case of Sumitestone A and hydrated Mg (OH) ₂ , a significant weight loss at about 400 ° C is pyrolyzed according to the following equation, and the main reason is that H ₂ O evaporates.

And can for microlithiasis A 708 ℃, hydrated Mg (OH) ₂ In appears that weight loss of 2.4% even near 637 ℃, which Mg, which, as shown in reaction scheme below, can be stabilized within the Mg (OH) ₂ lattice (OH) ₂ is It is interpreted as a peak that occurs during pyrolysis at high temperature.

In the case of the sumite stone A, the pyrolysis temperature is higher than that of the hydrated Mg (OH) ₂ , which is considered to be due to the fact that the sumite stone A is structurally more stable than the hydrated Mg (OH) ₂ .

In addition, even if the weight loss ratio up to 950 ° C considers the purity of Mg (OH) ₂ and the degree of pyrolysis of impurities, the weight loss ratio is more significant in Sumirite A than in the volatile substances such as water molecules in Mg (OH) ₂ samples. This may be due to the presence of a large amount of unreacted MgO present in hydrated Mg (OH) ₂ or unhydrated as in the reaction scheme below.

In this way, it is considered that in the hydrated Mg (OH) ₂ , the undehydrated MgO is present, resulting in defects in the Mg (OH) ₂ crystal structure and lowering of the pyrolysis temperature. From these thermal analysis data, the sumite stones used in the present invention can be evaluated as structurally and thermally more stable than the hydrated Mg (OH) ₂ .

Desulfurization Test

A laboratory-scale small reactor such as FIG. 5 was prepared to test the desulfurization performance of the slurry sample of Sumite stones and hydrated Mg (OH) ₂ .

Gas used in the experiment was a mixed gas of O ₂ 4%, SOx 1,000 ~ 2,000ppm and residual He was injected into the reactor at 30L / min. SOx removal efficiency was measured by measuring SOx concentration change before and after the reactor using a SOx analyzer (Horiba Co. SLFA-UV21). Sumirite and hydrated Mg (OH) ₂ samples were used after slurrying the same at a concentration of 1%. In the case of Sumi-seok, two particle sizes of 325mesh and 5,000mesh were used, and for hydrated Mg (OH) ₂ , 325mesh was used.

Results of Desulfurization Test

Desulfurization Performance with Sulfur Oxide Concentration-To compare the desulfurization performance of Sumirite A and Mg (OH) ₂ with similar particle size and purity, change the SOx concentration from 1,000 to 2,000 ppm The desulfurization performance of the samples was compared. At this time, the slurry concentration of the sample was 1%, the temperature of the reactor was compared at 60 ℃ under the same conditions, and as shown in Table 2 below, the SOx removal efficiency of the sumite stone was generally 3 ~ higher than the hydrated Mg (OH) ₂ . 5% higher.

Desulfurization performance according to the reaction temperature-After adjusting the temperature of the reactor to 40 ℃, 60 ℃, 80 ℃ in order to determine the optimum reaction temperature of the slurry of Sumiolite A, the concentration of SOx of the injection gas is 1,000ppm, 1,500ppm, 2,000 Desulfurization performance in ppm was examined. At this time, the sample concentration of Sumirite A used was 1%.

As shown in Table 3 below, the desulfurization performance of Sumite Stone A by reaction temperature was the highest in the reactor at 80 ° C, regardless of the concentration of SOx injection. ° C <80 ° C). This may be due to the excellent alkali activity in the high-temperature region, and it is believed that the alkali activity in this region is superior to the ability of the SOx gas to desorb by temperature.

Desulfurization Performance by Size of Sumirite Stone-To determine the effect of particle size on the desulfurization performance, Sulfite A (325mesh) and Sumirite B (5,000mesh) were used to compare the desulfurization performance. Sumirite stone used in this experiment had about 1% less MgO content than Sumistone B in Sumirite A, as shown in the chemical analysis table in Table 1.

Table 4 below shows the de-SOx performance when the concentration of SOx injected with two particle sizes of Sumistone is different. In the de-SOx performance, Sumi-e B, which has a finer particle size than Sumi-e A, showed better performance. This means that when the particle size of the tailingsite is small, the specific surface area of the reaction sample is increased, and the contact efficiency with SOx gas is increased to improve the SOx removal ability.

Desulfurization Performance According to the Activation of Sumirite Slurry-In order to examine the effect of sumirite activation on the desulfurization performance, after activating Sumirite slurry in reactor at 90 ℃ for 3 hours above atmospheric pressure, the concentration of SOx of injection gas is 1,000ppm The desulfurization performance was tested with varying 1,500 ppm and 2,000 ppm, and the results were compared with the inert tailings slurry.

As shown in Table 5 below, the desulfurization performance of the activated talcite slurry was increased by about 6-10% over that of the unactivated talcite slurry. This indicates that when the sumite stone is present in the form of stabilized Mg (OH) ₂ in its natural state and activated, it exhibits an effect of structural destabilization and improvement of reactivity.

1,000 ppm 1,500 ppm 2,000 ppm Activated Sumite Stone A 98% 93% 88% Unactivated Sumite Stone A 91% 87% 78%

The present invention provides a method for removing sulfur oxides by using a natural mineral Sumirite Slurry (Mg (OH) ₂ ), which can be used by the present invention. This can improve the economics of the desulfurization process. The present invention further provides the advantage of achieving an improved desulfurization efficiency by performing a desulfurization process using a tailings slurry.

Claims (11)

Preparing a brucite powder, Mixing the Sumite stone powder with water to obtain a Sumite stone slurry, and Contacting the tailings slurry with an exhaust gas comprising sulfur oxides to remove sulfur oxides from the exhaust gases, The method of removing the sulfur oxides by the tailings powder is characterized in that (0,0,1) peak is stronger than the (1,0,1) peak in the X-ray diffraction pattern. delete delete The method of claim 1, The method of removing the sulfur oxides by means of the tailings slurry is characterized in that the concentration of the tailingsite slurry is 20 to 50%. The method of claim 1, The wet desulfurization reaction of removing the sulfur oxides by contacting the tailings slurry with a flue gas containing sulfur oxides is characterized in that the temperature of the reactor, that is, the temperature of the circulating water, is performed at a temperature range of 55 to 75 ° C. Method for removing sulfur oxides by. The method of claim 1, The method of removing sulfur oxides by using a talcite slurry further comprising the step of activating the talcite slurry at a temperature in the range of 70 to 150 ° C. under a pressure above normal pressure. It is formed by mixing water and brucite powder prepared by screening, coarsely pulverizing and pulverizing the raw stone collected from the tailings mine. A crustite slurry, characterized in that the peak appears stronger than the (1,0,1) peak. The method of claim 7, wherein The tailings slurry is characterized in that the tailings slurry is activated in a temperature range of 70 ~ 150 ℃ under pressure above atmospheric pressure. delete delete The method of claim 7, wherein The Sumite stone slurry is a tasteite slurry, characterized in that the concentration of the tasteite 20 to 50%.

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