KR102260723B1 - Apparatus of mineralcarbonation using waste asbestos slate - Google Patents

Abstract

The present invention relates to a waste asbestos slate slurry supply unit for drying and pulverizing detoxified waste asbestos slate, mixing it with water and supplying it to the reaction in a slurry state; a pH adjusting tank for adjusting the pH to a neutral range of 7 by adding hydrochloric acid to the inputted waste asbestos slate slurry; a mineral carbonation reactor for precipitating calcium carbonate by reacting with the carbon dioxide flowing in from the carbon dioxide supply unit and the pH-adjusted slurry flowing in from the pH adjusting tank; Provided is a carbonate mineralization apparatus using detoxified waste asbestos slate including a carbon dioxide supply unit for supplying carbon dioxide contained in exhaust gas of a power plant.

Description

Carbonate mineralization apparatus using waste asbestos slate {APPARATUS OF MINERALCARBONATION USING WASTE ASBESTOS SLATE}

The present invention relates to a carbonate mineralization apparatus using detoxified asbestos slate, and more particularly, by establishing optimum carbonate mineralization conditions that can efficiently fix carbon dioxide using detoxified asbestos slate, environmental protection and It relates to a carbonate mineralization device using harmless asbestos slate that can produce useful minerals with high efficiency and inexpensive while improving public health.

Asbestos is a hydrated silicate mineral that is produced in the form of fibers or needles and is commercially used. According to the Occupational Safety and Health Administration, it is classified as asbestos only if it has an aspect ratio of 3:1 or more and a length of 5 μm or more. are classifying.

Asbestos can be largely divided into serpentine group asbestos, chrysotile, and amphibole group asbestos, amosite, crocidolite, anthophyllite, tremolite, and actinolite, according to mineralogical properties.

Asbestos has been used in more than 3,000 products such as textiles, construction materials, insulation materials, fire-resistance materials, and brake linings since the industrial revolution at the end of the 19th century due to its strong properties such as tensile strength, high temperature and low temperature environment, non-conduction, and strong chemical corrosion.

However, when products and wastes containing asbestos are weathered and introduced into the human body, they cause cell damage or transformation, and are not well excreted from the body, causing diseases such as lung cancer, asbestos lung, malignant mesothelioma, and pleural thickening. In fact, the incidence of lung disease among workers in industries that produce asbestos products or those exposed to the products has been steadily reported, and epidemiologic studies of lung diseases caused by asbestos have proven a link between inhalation of asbestos and certain lung diseases.

One of the representative wastes containing such asbestos is asbestos slate. Asbestos slate is composed of 10-20% of serpentine asbestos and 80-90% of cement. Calcium hydroxide, the main component of cement, dissolves in water over time, but other asbestos are released into the surrounding environment and cause human damage. threatening health. According to a recent survey by the Ministry of Environment, about 1.23 million dong of asbestos slate buildings are distributed nationwide, and it was used steadily until the 1990s. Recently, as asbestos was designated as a class 1 carcinogen, its use decreased after 2000. In addition, the majority (55.4%) of asbestos slate buildings in the country were concerned about asbestos scattering because their durability (30 years) had passed. In fact, 22% of asbestos was detected in the soil collected around buildings before the 1970s.

Currently, in Korea, these asbestos slates are collected by waste companies, sealed in polyethylene containers to prevent scattering, and covered in designated waste landfills. However, the waste asbestos landfill capacity is expected to reach saturation after 2016 (in 2017, 152,000 tons x 5 years). In addition, even if it is buried in a designated landfill site, there is a possibility that it may be exposed to the surrounding environment again due to weathering in the future, which is a problem.

The present invention has been devised to solve the problems of the prior art as described above, and its purpose is to establish optimal carbonate mineralization conditions that can efficiently fix carbon dioxide using harmless asbestos slate, An object of the present invention is to provide a carbonate mineralization device using harmless asbestos slate, which can produce useful minerals with high efficiency and inexpensive while protecting and improving public health.

The technical problem of the present invention as described above is achieved by the following means.

(1) a waste asbestos slate slurry supply unit for drying and pulverizing detoxified waste asbestos slate, mixing it with water, and supplying it to the reaction in a slurry state;

a pH adjusting tank for adjusting the pH to a neutral range of 7 by adding hydrochloric acid to the inputted waste asbestos slate slurry;

a mineral carbonation reactor for precipitating calcium carbonate by reacting with the carbon dioxide flowing in from the carbon dioxide supply unit and the pH-adjusted slurry flowing in from the pH adjusting tank;

Carbonate mineralization device using detoxified waste asbestos slate including a carbon dioxide supply unit for supplying carbon dioxide contained in the exhaust gas of a power plant.

(2) in (1) above,

The waste asbestos slate slurry is a carbonate mineral using detoxified waste asbestos slate, characterized in that the concentration of the waste asbestos slate slurry is adjusted to 8-10 g/L (1%) by mixing water with the detoxified dry waste asbestos slate powder. fire device.

(3) in (1) above,

The waste asbestos slate slurry is adjusted to have a concentration of 10 g/L (1%) of the waste asbestos slate slurry by mixing water with the detoxified dry waste asbestos slate powder, adjusted to pH 7 using hydrochloric acid, and reacted for 30 minutes to give calcium Carbonate mineralization apparatus using detoxified waste asbestos slate, characterized in that it obtains an eluate.

(4) in (1) above,

For the waste asbestos slate slurry, a primary calcium eluate is obtained with hydrochloric acid, and then a complex organic acid composed of phosphoric acid, tartaric acid, and propionic acid in a weight ratio (w/w) of 1:1:1 to 2:2:2 is added together with hydrochloric acid. However, carbonate mineralization apparatus using detoxified waste asbestos slate, characterized in that the pH is adjusted to 7 by adding 10 to 30% by weight based on the weight of hydrochloric acid.

(5) in (1) above,

After heating the waste asbestos slate slurry at 100 ° C for 10 to 20 minutes, water is added thereto and heated at 100 ° C for 20 to 30 minutes to facilitate the elution of calcium in the subsequent process. Carbonate mineralization apparatus using detoxified waste asbestos slate, characterized in that.

According to the present invention as described above, by establishing the optimum carbonate mineralization conditions that can efficiently fix carbon dioxide using detoxified asbestos slate, environmental protection and public health are improved, and useful minerals are efficiently and inexpensively produced Provided is a carbonate mineralization apparatus using detoxified waste asbestos slate that can be manufactured in a safe manner.

1 is a block diagram of a carbonate mineralization apparatus using waste asbestos slate according to the present invention.
Figure 2 is a waste asbestos slate (WAS) XRF analysis diagram.
Figure 3 is a detoxified waste asbestos slate (HWAS) XRF analysis diagram.
Figure 4 is a waste asbestos slate (WAS) SEM-EDS analysis diagram.
5 is a detoxified waste asbestos slate (HWAS) SEM-EDS analysis diagram.
^{Figure 6 is Ca 2+} elution concentration for each pH of WAS, HWAS, WC
^{Figure 7 is Mg 2+} elution concentration by pH of WAS, HWAS, WC

The carbonate mineralization method using detoxified waste asbestos slate according to the present invention comprises the steps of preparing a slurry of waste asbestos slate by mixing dry waste asbestos slate powder with water; obtaining a calcium eluate by adding hydrochloric acid to the waste asbestos slate slurry; performing a mineral carbonation reaction by adding carbon dioxide to the calcium eluate; and recovering the calcium carbonate produced by the mineral carbonation reaction.

1 is a carbonate mineralization apparatus using detoxified waste asbestos slate according to the present invention, including a waste asbestos slate slurry supply unit 10, a pH adjustment tank 20, a calcium carbonate precipitation tank 30, and a carbon dioxide supply unit 40 do.

The waste asbestos slate slurry supply unit 10 dry and pulverize the detoxified waste asbestos slate, and then mix it with water and supply it to the reaction in a slurry state. Preferably, the waste asbestos slate slurry is prepared by mixing detoxified dry waste asbestos slate powder with water (for example, mixing 1 L of distilled water with 8-10 g of dry waste asbestos slate) so that the concentration of the waste asbestos slate slurry is 8 to 10 g/L (1 %), but preferably adjusted to be 10 g/L.

In the present invention, the detoxified waste asbestos slate can be obtained by recovering the waste asbestos slate, pulverizing it to 1 mm or less, mixing the obtained pulverized material with an inorganic material (eg, SiC), and heating it to about 1,100° C. with a microwave.

Preferably, the detoxified waste asbestos slate slurry obtained as described above is heated at 100° C. for 10 to 20 minutes, then 1-3 times water is added thereto secondarily and heated at 100° C. for 20 to 30 minutes in the subsequent process. pretreatment to facilitate the elution of calcium, and finally adjust the concentration of the slurry to be 8 to 10 g/L (1%), preferably to 10 g/L. In this case, the effect of softening the tissue is provided so that subsequent dissolution of calcium by acid can occur more easily.

In the pH adjusting tank 20, hydrochloric acid is added to the inputted waste asbestos slate slurry, and the pH is preferably adjusted to a neutral range of 2 to 7, more preferably pH 7. Although it shows the highest calcium ion concentration at a low pH, for example, pH 4, when the calcium eluate is applied to the subsequent mineral carbonation process, economical efficiency and environmental impact according to the pH of the process waste solution and acid input are considered. As a result, it is judged that the dissolution condition of pH 7 can secure sufficient calcium necessary for the mineral carbonation reaction, reduce the burden on the environment, and increase the efficiency.

More preferably, hydrochloric acid is added to the slurry to obtain a primary calcium eluate, and then a complex organic acid composed of phosphoric acid, tartaric acid, and propionic acid in a weight ratio (w/w) of 1:1:1 to 2:2:2 is mixed with hydrochloric acid. In addition, but adding 10 to 30% by weight relative to the weight of hydrochloric acid to adjust the pH to 7 shows high efficiency in dissolution of calcium.

The mineral carbonation reactor 30 is a reaction tank in which the mineral carbonation process occurs, and reacts with the carbon dioxide flowing in from the carbon dioxide supply unit 40 and the pH-adjusted slurry flowing in from the pH adjusting tank 20 to precipitate calcium carbonate.

When carbon dioxide is introduced into the gas inlet of the upper part of the mineral carbonation reactor 30, it is induced to diffuse as small bubbles by the pores of the perforated plate (not shown) at the bottom of the gas inlet pipe and acid-treated to elute calcium from the waste asbestos slate slurry. After passing through the supernatant and reacting, the carbon dioxide gas discharged to the water surface exits through the gas outlet _{and moves to the CO 2} sensor 50 so that the concentration of carbon dioxide emitted is measured in real time.

The carbon dioxide supply unit 40 may use power generation facility exhaust gas, and the supply type is not particularly limited, and the _{exhaust gas having an average CO 2} emission concentration of about 5% is directly supplied or collected in the form of compressed gas in the tank. It can also be supplied in a charged state.

The calcium carbonate formed by the reaction is precipitated at the bottom of the mineral carbonation reactor 30, and the precipitated calcium carbonate is separately recovered.

Hereinafter, the present invention will be described in more detail by the following examples. However, this is for easier understanding of the present invention, and is not intended to limit the present invention through these.

[Example 1] Metal ion elution test

Experimental raw materials and process

Experimental materials are Waste Asbestos Slate (hereinafter 'WAS' (diameter less than 1mm), and Harmless Waste Asbestos (hereinafter 'HWAS' (diameter less than 1mm, advanced technology) made harmless by irradiating inorganic materials with microwaves. Provided by the researcher) Waste concrete was also used as a comparative material (hereinafter referred to as 'WC').

XRF(Fluoresecence X-ray Element Analyzer, SEA2220A and mobile:SEA 200, Sll Nano Technology Inc), SEM-EDS(NORMAL SEM-EDS, JSM-5400, INCAx-sight, Jeol/Oxford) of Gongju University Joint Lab. Analysis was performed using ICP-OES/AES (Ioductively coupled plasma optical emission sepctrometer, OPTIMA200 DV, Perkinelmer), and the raw material Ca ²⁺ , Mg ²⁺ _{Elution was conducted using H 2} SO ₄ and HCl for WAS, HWAS, and WC.

Experimental result 1: XRF analysis

^{It was confirmed to what extent Ca 2+} and Mg ^{2+, which} are substances necessary for mineral carbonation, were contained in the waste asbestos slate and the detoxified waste asbestos slate. As a result of XRF measurement, the CaO content was WAS (40.8 wt%) and HWAS (37.9 wt%), and the MgO content was WAS (10.6 wt%) and HWAS (10.8 wt%).

XRF analysis result of waste asbestos slate (WAS) and detoxified waste asbestos slate (HWAS) XRF Result (wt%) WAS HWAS WC[9] MgO 10.6 10.8 2.7 Al ₂ O ₃ 7.4 8.2 8.7 SiO ₂ 23.1 25.9 35.8 K ₂ O 2.8 2.4 4.9 CaO 40.8 37.9 22.1 Fe ₂ O ₃ 15.3 14.8 18.5

Experimental result 2: SEM-EDS analysis

As a result of averaging and analyzing 8 spectrums of waste asbestos slate, Ca was 25.3 wt%, and as a result of averaging 12 spectrums of harmless waste asbestos slate, Ca was analyzed as 37.7 wt%, and Mg was analyzed as WAS 10.2 wt% , HWAS was analyzed at 6.2 wt%. WC (Waste Concrete) was analyzed as 16.2 wt% and 5.4 wt% of Ca and Mg, which is lower than that of detoxified waste asbestos slate.

Results of SEM-EDS analysis of waste asbestos slate and detoxified waste asbestos slate (wt%) SEM-EDS result Average WAS
norm.C HWAS
norm.C WC[9]
norm.C C 21.6 5.9 7.1 O 30.2 34.3 38.7 Na - 0.9 0.6 Mg 10.2 6.2 5.4 Al 1.2 2.3 8.6 Si 9.7 8.7 14.2 K 0.5 0.8 3.1 S 0.6 0.9 0.8 Ca 25.3 37.7 16.2 Fe 1.1 1.4 5.5 Cu - 0.61 0.3 SUM 100.41 99.17 100.5

Experimental result 3: ICP-OES/AES analysis

The waste-asbestos slate sample and the detoxified waste-asbestos sample were mixed with water and adjusted to 1 g/100 mL to form a slurry. ^{Ca 2+} , Mg ²⁺ , and Si ⁺ were eluted for 5 minutes while the elution solvent was _{applied to the slurry using H 2} SO ₄ and HCl, respectively, to obtain pH 11, 9, 7, 5, and 3 state. Analyzed by ICP-OES / AES in HCl, pH 3 waste asbestos slate Ca ²⁺ is Ca ²⁺ in 2,761.71mg / L, the detoxified asbestos waste 2,65.36 mg/L was analyzed to be almost the same high. Mg ²⁺ is in the same manner as Ca ²⁺ HCl, in a waste asbestos slate at pH 3 is Mg ²⁺ waste asbestos slate or a detoxifying've found to 93.88mg / L concentration showed a higher concentration to 213.87mg / L.

Comparison ^{of ICP-OES/AES Ca 2+} Concentrations of Waste Asbestos Slate, Detoxified Waste Asbestos Slate, and Waste Concrete pH WAS (mg/L) HWAS (mg/L) WC (mg/L) H ₂ SO ₄ HCl H ₂ SO ₄ HCl HCl 11 103.02 54.76 96.89 128.68 30.98 9 693.48 678.08 1,287.51 1,644.15 151.78 7 965.53 2,089.63 1,547.29 2,132.80 563.23 5 1,826.80 1,893.90 994.01 2,592.40 826.45 3 2,187.43 2,761.71 1,043.60 2,653.36 984.17

Comparison ^{of ICP-OES/AES Mg 2+} Concentrations of Waste Asbestos Slate, Detoxified Waste Asbestos Slate, and Waste Concrete pH WAS (mg/L) HWAS (mg/L) WC (mg/L) H ₂ SO ₄ HCl H ₂ SO ₄ HCl HCl 11 0.42 0.48 0.09 0.09 0.17 9 10.19 6.32 41.17 90.24 1.36 7 17.80 43.10 123.87 133.63 7.99 5 33.21 34.17 165.19 190.93 18.82 3 81.05 93.88 201.46 213.87 34.75

As a result of analyzing waste asbestos slate (WAS), detoxified waste asbestos slate (HWAS), and waste concrete (WC) by various methods as described above _{, it was eluted with H 2} SO ₄ , HCl and the pH was adjusted while stirring at 1 g/100 ml. did. As a result of elution, the lower the pH, the ^{higher the concentrations of Ca 2+ , Mg 2+} , and the higher the elution concentration of ions related to mineral carbonation in HWAS than in WAS. In the process of detoxification, it is judged that it has been transformed into a more favorable raw material for mineral carbonation according to the destruction and transformation of the crystal phase structure through high-temperature microwaves. When eluted with HCl at pH 5, Ca ²⁺ of WAS was 189.3 mg(Ca ²⁺ )/1 g (WAS), and Ca ²⁺ of HWAS was 259.2 mg(Ca ²⁺ )/1 g (HWAS), which was different from pH 3 Contrasting results were obtained, indicating that the dissolution of the crystallized structure due to detoxification was advantageous in that raw materials capable of mineral carbonation were eluted even if the pH was not lowered. In addition, waste concrete shows only 1/2 the amount of elution compared to waste asbestos slate and detoxified waste asbestos slate, so waste asbestos slate and detoxified waste asbestos slate are judged to be more advantageous raw materials for mineral carbonation.

^{[Example 2] Ca 2+} ion elution in waste asbestos slate according to pH using complex organic acid

After the primary treatment with hydrochloric acid, a complex organic acid composed of phosphoric acid, secondary tartaric acid, and propionic acid in a weight ratio (w/w) of 1:1:1, respectively, was added together with hydrochloric acid, and 10% by weight relative to the weight of hydrochloric acid was added. ^{When the Ca 2+} ion elution experiment was performed by the same procedure as in Example 1 above, except that the pH was adjusted to 7, HWAS was shown as 2,315 mg/L at pH 7.

[Example 3] Effect of ^{reaction time on Ca 2+ ion elution}

As a result of eluting calcium ions in detoxified waste asbestos slate (1 g/L) according to reaction time at pH 5 using hydrochloric acid (HCl), an average of 2,653.36 mg/L was shown at 5 minutes of reaction time, and an average of 2,653.36 mg/L was obtained at 10 minutes. 3,242.5 mg/L, average 4,235.5 mg/L at reaction time 15 minutes, average 6,265.0 mg/L at reaction time 20 minutes, average 7,385.5 mg/L at reaction time 25 minutes, average 8,107.0 mg/L at reaction time 30 minutes Average 8,185.5 mg/L at 35 minutes, average 8,329.0 mg/L at reaction time 40 minutes, average 8,280.0 mg/L at reaction time 45 minutes, average 8,149.0 mg/L at reaction time 50 minutes, average 8,340.0 at reaction time 55 minutes It was expressed as an average of 8,295.0 mg/L, at mg/L, a reaction time of 60 minutes. The concentration of eluted calcium continued to increase until the reaction time of 30 minutes, but at 30 minutes or more, the concentration increase was slow due to exceeding the optimal reaction time. Therefore, it is judged that the reaction time of 30 minutes in the calcium ion elution step is suitable.

[Example 4]

The detoxified waste asbestos slate slurry (1 g/L) used in Example 1 was heated at 100° C. for 20 minutes, and then water was added thereto and heated to 100° C. for 30 minutes to increase the concentration of the waste asbestos slate slurry. When the same experiment as in Example 1 is repeated using the adjustment again to 1 g/L (pH 7), the elution concentration of calcium ions at 5 minutes appears as high as 2,678.2 mg/L on average.

[Example 5]

In order to evaluate the mineral carbonation reaction efficiency, a batch reaction process as shown in FIG. 1 was devised. The carbon dioxide gas used in the experiment was used _{by mixing Air and 99.99% CO 2} with MFC (Mass Flow Controller) to prepare 5% CO _{2 so that the average CO 2} emission concentration of the power plant exhaust gas was 5%.

_{5% CO 2} gas mixed and prepared by MFC is introduced into the mineral carbonation reactor as shown in FIG. 1 and is filled with the calcium eluate (sample obtained at pH 7 using the detoxified waste asbestos slate of Example 1) and After the reaction, it is discharged through the gas outlet at the top of the mineral carbonation reactor. The discharged carbon dioxide gas was _{introduced into the CO 2} sensor to measure the concentration of the exhaust gas. In the mineral carbonation reactor of FIG. 1, when carbon dioxide is introduced into the upper gas inlet, it is induced to diffuse as small bubbles by the voids in the bottom perforated plate of the gas inlet pipe, and passes through the supernatant of the acid-treated solution to elute calcium from the waste asbestos slate Then, the carbon dioxide gas discharged to the water surface is devised so that the concentration of the emitted carbon dioxide is measured in real time by _{passing through the gas outlet and moving to the CO 2 sensor.}

In addition, in order to confirm the reaction trend during the mineral carbonation reaction in the mineral carbonation reactor, the CO ₂ concentration and the calcium ion concentration were measured in real time. As a result, as shown in Table 5, as the concentration of carbon dioxide discharged and the concentration of calcium ions in the sedimentation tank decreased, the sedimentation at the bottom was observed with the naked eye, indicating that the mineral carbonation reaction was proceeding smoothly.

reaction time CO ₂ Ca ²⁺ (mg/L) 10 minutes 3.2% 1,518.7 20 minutes 2.3% 682.8 30 minutes 0.2% 325.3

As described above, although described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

10: Waste asbestos slate slurry supply unit
20: pH adjustment tank
30: calcium carbonate precipitation tank
40: carbon dioxide supply unit

Claims (5)

a waste asbestos slate slurry supply unit for drying and pulverizing the detoxified waste asbestos slate, mixing it with water and supplying the slurry to the reaction;
a pH adjusting tank for adjusting the pH to a neutral range of 7 by adding hydrochloric acid to the inputted waste asbestos slate slurry;
a mineral carbonation reactor for precipitating calcium carbonate by reacting with the carbon dioxide flowing in from the carbon dioxide supply unit and the pH-adjusted slurry flowing in from the pH adjusting tank; and
Including a carbon dioxide supply unit for supplying carbon dioxide contained in the exhaust gas of the power generation facility,
In the waste asbestos slate slurry supply unit, water is mixed with the detoxified dry waste asbestos slate powder and adjusted so that the concentration of the waste asbestos slate slurry is 8 to 10 g/L,
In the pH adjustment tank, hydrochloric acid is added to the waste asbestos slate slurry to adjust the pH to a neutral region and react for 30 to 60 minutes to obtain a calcium eluate. delete delete The method of claim 1,
For the waste asbestos slate slurry, a primary calcium eluate is obtained with hydrochloric acid, and then a complex organic acid composed of phosphoric acid, tartaric acid, and propionic acid in a weight ratio (w/w) of 1:1:1 to 2:2:2 is added together with hydrochloric acid. However, carbonate mineralization apparatus using detoxified waste asbestos slate, characterized in that the pH is adjusted to 7 by adding 10 to 30% by weight based on the weight of hydrochloric acid. The method of claim 1,
After heating the waste asbestos slate slurry at 100 ° C for 10 to 20 minutes, water is added thereto and heated at 100 ° C for 20 to 30 minutes to facilitate the elution of calcium in the subsequent process. Carbonate mineralization apparatus using detoxified waste asbestos slate, characterized in that.

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