KR20120110425A - Method of asbestos detoxification and calcium compound reaction liquid used therefor - Google Patents

Abstract

PURPOSE: An asbestos detoxification method and calcium compound reaction liquid used therefor are provided to reduce the detoxification cost of asbestos. CONSTITUTION: An asbestos detoxification method comprises a step of heating the mixture of a calcium compounds-containing reaction solution and an asbestos-containing material to 800-1000 deg.C. The reaction solution comprises at least one selected from calcium chloride, calcium carbonate, and calcium oxide and water.

Description

Asbestos detoxification treatment method and calcium compound reaction liquid used in the same {METHOD OF ASBESTOS DETOXIFICATION AND CALCIUM COMPOUND REACTION LIQUID USED THEREFOR}

The present invention relates to a method for treating asbestos detoxification and a calcium compound reaction solution used therein, and more particularly, by mixing a reaction solution containing a calcium compound and an asbestos-containing material and heating the mixture to a specific temperature range, The present invention relates to an asbestos detoxification treatment method capable of completely decomposing asbestos at low temperatures by cutting Si bonds, and to a calcium compound reaction solution used therein.

Asbestos is a known material that has been widely used for a long time because of its amazing properties. Asbestos, for example, was excellent in heat resistance and began to be used as a wick for lanterns used in temples. The word "asbestos" is derived from the Greek word meaning "immortal, intractable." Asbestos is a generic term for natural silicate mineral fiber, and there are kinds of asbestos (Chrysotile), cationic (Actinolite), anthracite (Athophylite), brown stone (Amosite), tremite (Crocidolite) and the like.

Asbestos is well bent, heat resistant and weakly acidic, and has been widely used in various ways since the modernization of technology. Asbestos is known to contain more than 3,000 products, and asbestos has been used in almost all economic sectors around the world.

90% of asbestos is used for building materials, half of which is used to manufacture slate. Specifically, 90% for building materials, roofs, exterior walls, partitions, interior materials, 6.5% for brake linings and clutches of automobiles, 2% for industrial machinery, civil construction machinery, cranes, machine tools, etc. 0.6% for materials, 0.4% for water, simple water, agricultural water, industrial water, 0.1% for ships, electrical insulation materials, heat-resistant materials, 0.1% for boilers, chimneys, firewalls for industrial machinery, 0.3 for other seal materials, etc. % Is used.

On the other hand, since asbestos is a mineral silicate, it was considered that there are no harmful factors to the human body, and the health risks of asbestos dust were not treated specially unlike the case of ordinary dust. Asbestos was not treated as a hazardous substance, the world's asbestos production in 1966 reached 2.8 million tonnes, and in 1975 it increased to 5.2 million tonnes.

However, the US Occupational Safety and Health Administration (OSHA) has recently classified asbestos dust as a first-class carcinogen that can cause asbestos, lung cancer and malignant mesothelioma when inhaled through a long-term respiratory system. Among them, malignant mesothelioma is a malignant carcinoma of the pleura and peritoneal mesothelioma. The biggest cause of this is asbestos, asbestos. In particular, asbestos-treated workers often suffer from asbestos lung disease or death from lung cancer or malignant mesothelioma. In recent years, there have been reports of malignant mesothelioma occurring in the neighborhood of asbestos factories, as well as cases of family members with malignant mesothelioma caused by asbestos attached to clothing of workers working in asbestos factories as well as those who directly handle asbestos.

On the other hand, in Korea, the legal regulations or regulations on asbestos use are still insufficient, and the cumulative imports in 1997 exceeded 1,870,892 tons. Moreover, as the international price of asbestos fell in 1983 due to the ban on imports of developed countries such as Japan, the official imports of domestic asbestos more than doubled.

Although the harmless treatment of a large amount of asbestos is an essential situation, the domestic asbestos treatment currently has only a high-temperature melting method and a landfill method by designated waste that change the state of asbestos by heating to a temperature of more than 1,500 ℃. Among them, the high-temperature melting method focuses on the characteristics of asbestos (average melting point of 1,540 ° C.), which is not harmful if it is sufficiently melted. However, since a high temperature heat source is required, the utilization rate is considerably low due to the high cost of high oil prices. Therefore, while relying on the landfill method in Korea, the landfill method is a temporary method that can not completely harm the asbestos, and there is a risk of secondary exposure of workers and neighboring residents to asbestos by the scattering of asbestos during the landfill process. In addition, there is a solidification method to solidify the asbestos-containing material to remain in that state for about 20 years, but this is a temporary treatment method by simple solidification, which may cause long-term harm to the human body.

Therefore, there is an urgent need to develop a technology capable of permanently and stably harming asbestos at low cost.

The present invention is to solve the problems of the prior art as described above, by completely decomposing asbestos at low temperature, asbestos detoxification treatment method capable of permanently detoxifying asbestos at low cost and calcium compound reaction solution used therein To provide a technical problem.

In order to achieve the above technical problem, the present invention provides a method for treating asbestos, characterized in that after mixing the reaction liquid containing a calcium compound and asbestos-containing material, the mixture is heated to a temperature of 800 ~ 1,000 ℃. .

In another aspect, the present invention provides a calcium compound reaction solution for asbestos detoxification treatment used in the treatment method.

In still another aspect of the present invention, an asbestos treated by the treatment method is provided.

According to the present invention, asbestos, which is a harmful substance that harms health for a long time, can be permanently and stably harmlessly treated, and can be treated at a lower temperature than the conventional high temperature melting method, thereby reducing energy consumption and greatly reducing harmlessness costs. Asbestos can be simply detoxified in a short time.

Figure 1 shows an SEM analysis of asbestos before detoxification.
Figures 2 to 8 are SEM analysis photographs of fired products after asbestos detoxification treatment by maintaining at 800 ℃ for 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes and 120 minutes respectively according to the present invention will be.
9 shows the XRD pattern of asbestos before detoxification.
Figure 10 shows the XRD pattern of the fired product after the asbestos detoxification treatment by maintaining at 800 ℃ for 10 minutes, 20 minutes and 50 minutes respectively according to the present invention.
Figure 11 shows the XRD pattern of the fired product after the asbestos detoxification treatment by maintaining for 30 minutes and 40 minutes at 800 ℃ according to the present invention.
Figure 12 shows the XRD pattern of the fired product after asbestos detoxification treatment by maintaining at 800 ℃ 60 minutes and 120 minutes respectively in accordance with the present invention.

Hereinafter, the present invention will be described in detail.

Asbestos detoxification treatment method of the present invention is to mix the reaction liquid containing a calcium compound and asbestos-containing material, and then to heat the mixture to a temperature of 800 ~ 1,000 ℃, to completely remove any type of asbestos-containing waste at low cost And can be harmlessly treated safely.

The reaction solution used in the treatment method of the present invention contains a calcium compound, and serves to decompose asbestos (fibrous asbestos) by cutting the chemical bond between Mg and Si in the asbestos compound through a chemical reaction in a heated state.

The reaction solution may be prepared by mixing a calcium compound and a solvent by an appropriate method, and the production method is not particularly limited.

The calcium compound can be used without particular limitation as long as it can break the Mg-Si bond of asbestos through reaction with asbestos, and for example, calcium chloride, calcium carbonate, calcium oxide, calcium hydroxide, and the like can be used.

The solvent used to dissolve the calcium compound can be used without particular limitation so long as it does not interfere with the reaction between the calcium compound and asbestos, for example, water, acetic acid and the like can be used.

Preferably, calcium chloride; At least one selected from calcium carbonate and calcium oxide; And water; using a reaction solution containing. In one embodiment, when using a mixture of calcium chloride, calcium oxide and water as the reaction solution, decomposition of asbestos proceeds as in Scheme 1 below.

[Reaction Scheme 1]

Mg ₃ Si ₂ O ₅ (OH) ₄ + 2CaO + 2CaCl _2- > 2Ca ₂ SiO ₃ Cl ₂ + 3MgO + 2H ₂ O

Preferred contents of calcium chloride, calcium carbonate and calcium oxide each are 1.7 to 2.2 mol, more preferably 1.9 to 2.1 mol and most preferably 2 mol per mol of asbestos to be treated. If the content is less than 1.7 moles, there is a lack of sufficient calcium components necessary for asbestos decomposition, the undecomposed asbestos may be present, may not achieve the required harmless effect, if the content exceeds 2.2 moles unreacted calcium compound Many of these remain and can increase the overall processing cost.

Further, the preferred contents of calcium chloride, calcium carbonate and calcium oxide are 70 to 90 parts by weight, 60 to 80 parts by weight and 35 to 45 parts by weight, respectively, relative to 100 parts by weight of asbestos requiring treatment. If the content is less than the lower limit, asbestos may be insufficiently decomposed. If the content exceeds the upper limit, a large number of unreacted calcium compounds may remain, thereby increasing the overall treatment cost.

The preferred content of water is 310 to 330 parts by weight based on 100 parts by weight of asbestos which needs treatment. If the content is less than 310 parts by weight there may be a problem in the sufficient reactivity of asbestos and the reaction solution, if the content exceeds 330 parts by weight may be economically lowered due to the presence of unnecessary moisture.

According to the present invention, after mixing the reaction solution and the asbestos-containing material, the mixture is heat-treated at a temperature of 800 to 1,000 ° C. to make the asbestos harmless, and it can be harmlessly treated at a low temperature of about 800 ° C. so that the existing high temperature. Compared to the melting method, energy consumption can be greatly reduced.

The method of mixing the reaction liquid and the asbestos-containing material is not particularly limited. For example, a method of mixing or impregnating an asbestos-containing material with a reaction solution provided therein, a method of simultaneously mixing respective components of an asbestos-containing material and a reaction solution, first mixing some components of the asbestos-containing material and the reaction solution, and then rest of the reaction. The method of mixing a liquid component, etc. can be used.

The method of heating the mixture of the reaction liquid and the asbestos-containing material is also not particularly limited, and in particular, since the present invention treats at a lower temperature than the conventional high temperature melting method, it is possible to effectively decompose asbestos even when heated using a general electric furnace or the like. Can be.

Unlike the conventional high temperature melting method (heating to about 1,500 ° C), the present invention can detoxify asbestos by heating only to about 800 ° C. Specifically, the mixture of the reaction solution and the asbestos-containing material is heated to 800 to 1,000 ° C, preferably 800 to 900 ° C, more preferably 800 to 850 ° C, most preferably 800 ° C.

If the heating temperature is less than 800 ℃ asbestos decomposition reaction may not proceed smoothly, if the heating temperature exceeds 1,000 ℃ energy consumption increases can not be expected to greatly reduce the treatment cost.

In one embodiment, the mixture of reaction liquid and asbestos-containing material is heated to the above temperature range for 2 to 4 hours, more preferably 2 to 3 hours, and most preferably about 2 hours. If the heating time is less than 2 hours, the solvent may be evaporated due to rapid temperature increase, insufficient reaction of asbestos and reaction liquid may occur, and asbestos change may not occur. If the heating time exceeds 4 hours, the total treatment time increases. It can be difficult to maximize energy savings through reactions at lower temperatures.

In another embodiment, the mixture of the reaction solution and the asbestos-containing material is heated to a temperature of 800 ~ 1,000 ℃, and then maintained at the elevated temperature for 5 to 130 minutes. If the holding time is less than 5 minutes may not provide sufficient time required for the asbestos decomposition reaction, if the holding time is more than 130 minutes may be consumed unnecessary energy when the decomposition reaction of asbestos is already completed.

According to another aspect of the invention, calcium chloride; At least one selected from calcium carbonate and calcium oxide; And asbestos-containing calcium compound reaction solution for asbestos detoxification treatment, including; and asbestos treated by the treatment method as described above is provided.

Hereinafter, the present invention will be described more specifically by way of examples. However, these examples are provided only for the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

Example  One

According to the ingredients and contents of Table 1 below, asbestos and calcium carbonate were mixed in an aqueous solution of calcium chloride dissolved in pure water and placed in a crucible. The crucible was put into a heating furnace and heated up from room temperature to 800 ° C. over 2 hours. The mixture was kept at 800 ° C. for 10 minutes.

Example  2

The mixture was treated in the same manner as in Example 1 except that the mixture was kept at 800 ° C. for 20 minutes.

Example  3

The mixture was treated in the same manner as in Example 1 except that the mixture was kept at 800 ° C. for 30 minutes.

Example  4

The mixture was treated in the same manner as in Example 1 except that the mixture was kept at 800 ° C. for 40 minutes.

Example  5

The mixture was treated in the same manner as in Example 1 except that the mixture was kept at 800 ° C. for 50 minutes.

Example  6

The mixture was treated in the same manner as in Example 1 except that the mixture was kept at 800 ° C. for 60 minutes.

Example  7

The mixture was treated in the same manner as in Example 1 except that the mixture was kept at 800 ° C. for 120 minutes.

[Table 1]

asbestos Degradation Performance Test

According to the examples, the mixtures held at 800 ° C. for 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes and 120 minutes, respectively, were removed from the heating furnace and cooled to obtain respective fired products. The calcined product was washed with water and dried to remove excess calcium chloride, thereby obtaining specimens for each holding time.

Asbestos before treatment and each specimen after treatment were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). (Analyzed according to JIS A 1481.)

SEM analysis pictures are shown in FIGS. 1 to 8, and XRD pattern pictures are shown in FIGS. 9 to 12.

As shown in Figures 1 to 8, the specimens treated according to the present invention (Figs. 2 to 8) at each holding time, asbestos fibers as in normal asbestos (Fig. 1) were not detected.

In addition, as shown in Figs. 9 to 12, the XRD pattern of ordinary asbestos (Fig. 9) showed a strong peak (Chrysotile) near 12.4 °, which is an intrinsic diffraction angle of asbestos, but the specimen treated according to the present invention (Figs. 10 to Fig. 10). 12) proved that asbestos was stably harmless because no inherent peak of asbestos was observed.

Claims (8)

Asbestos-free treatment method characterized in that for heating the mixture to a temperature of 800 ~ 1,000 ℃ after mixing the reaction liquid containing a calcium compound and asbestos-containing material. The method of claim 1, wherein the reaction solution is calcium chloride; At least one selected from calcium carbonate and calcium oxide; And water; Asbestos detoxification treatment method comprising a. According to claim 2, based on 100 parts by weight of asbestos requiring treatment
70 to 90 parts by weight of calcium chloride; 60 to 80 parts by weight of calcium carbonate; And 310 to 330 parts by weight of water; asbestos-free treatment method characterized in that for applying a reaction solution comprising a. According to claim 2, based on 100 parts by weight of asbestos requiring treatment
70 to 90 parts by weight of calcium chloride; Calcium oxide 35 to 45 parts by weight; And 310 to 330 parts by weight of water; asbestos-free treatment method characterized in that for applying a reaction solution comprising a. The method of claim 1, wherein the mixture of the reaction liquid and the asbestos-containing material is heated to a temperature of 800 to 1,000 ° C. over 2 to 4 hours. The method of claim 1, wherein after heating the mixture of the reaction liquid and the asbestos-containing material to a temperature of 800 ~ 1,000 ℃, the temperature is maintained for 5 to 130 minutes. Calcium chloride; At least one selected from calcium carbonate and calcium oxide; And water; calcium compound reaction solution for asbestos detoxification treatment comprising water. Asbestos treated by the method according to any one of claims 1 to 6.

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