JP2009291730A5 - - Google Patents

Description

In the following, a plurality of examples, comparative examples and reference examples of the present invention including Example 15 are shown, but the present invention is not limited in any way by these examples and is specified by the claims. Needless to say, it is something.

Reference example A
0.5 g of asbestos yarn and 0.5 g of sodium orthosilicate n-hydrate (SiO ₂ / M ₂ O molar ratio = 0.5) were put in a crucible with a capacity of 50 ml, and the mixture was stirred for about 10 seconds with a medicine basket. Thereafter, the crucible was covered and charged in an electric heating furnace (Electric furnace KBF-894N manufactured by Koyo Lindberg Co., Ltd.), and heated in the electric furnace at 900 ° C. for 1 hour. Thereafter, the mixture was allowed to cool to room temperature, and the contents were taken out and observed with a scanning electron microscope.

Reference example B
The same operation as in Reference Example A was performed, except that 0.5 g of anhydrous sodium metasilicate (SiO ₂ / M ₂ O molar ratio = 1) was used as the sodium silicate.

Reference example C
The same operation as in Reference Example A was performed, except that 0.5 g of Ecolayer powder (SiO ₂ / M ₂ O molar ratio = 2) was used as sodium silicate.

Reference example D
The same operation as in Reference Example A was performed, except that 0.5 g of medium mole cullet (SiO ₂ / M ₂ O molar ratio = 3) was used as sodium silicate.

Reference examples E and F
The same operation as in Reference Example A was performed except that heating was performed at 750 ° C. ( Reference Example E ) or 1200 ° C. ( Reference Example F ) instead of heating at 900 ° C. (In the case of heating at 1200 ° C., We used Motoyama Co., Ltd. oxidation atmosphere ultra-high temperature electric furnace KB-2030D as an electric heating furnace.

Reference examples GI
Instead of heating at 900 ° C., the same operation as in Reference Example B was carried out except that heating was carried out at 600 ° C. ( Reference Example G ), 750 ° C. ( Reference Example H ) or 1200 ° C. ( Reference Example I ). When heating at ℃, we used Motoyama Co., Ltd. oxidizing atmosphere ultra-high temperature electric furnace KB-2030D).

The observation results of each electron microscope ( Reference Examples G and H ) or visual observation ( Reference Example I ) are as shown in Table 2 below.

Reference examples J-M
Similar to Reference Example C , except heating at 600 ° C. ( Reference Example J ), 750 ° C. ( Reference Example K ), 1000 ° C. ( Reference Example L ) or 1200 ° C. ( Reference Example M ) instead of heating at 900 ° C. The operation was performed (in the case of heating at 1000 ° C. and 1200 ° C., an ultrahigh temperature electric furnace KB-2030D manufactured by Motoyama Co., Ltd. was used as the electric heating furnace).

The observation results of each electron microscope ( Reference Examples J, K and L 1 ) or visually ( Reference Example M 1 ) are as shown in Table 2 below.

Reference example N
The same operation as in Reference Example D was performed except that heating was performed at 1200 ° C. ( Reference Example N ) instead of heating at 900 ° C. It was used).

Comparative Example 1
Place 0.5 g of asbestos yarn used in Reference Example A into a crucible with a capacity of 50 ml, cover the crucible and place it in an electric heating furnace (Electric furnace KBF-894N manufactured by Koyo Lindberg Co., Ltd.). At 900 ° C. for 1 hour. Thereafter, the mixture was allowed to cool to room temperature, and the inside of the crucible was visually observed. As a result, the asbestos yarn in the crucible was slightly shrunk and was in a stiff state. When the crucible contents after the heat treatment were taken out and observed with a scanning electron microscope, the needle-like fiber structure was not lost (FIG. 4-B (c)).

Comparative Example 2
The same operation as in Reference Example A was performed except that 1.66 g of an aqueous solution containing 30% sodium silicate having a SiO ₂ / M ₂ O molar ratio of 2 was used as sodium silicate. When the crucible was charged in an electric furnace and heated, foaming occurred rapidly and the contents overflowed from the crucible, so the test was stopped.

Comparative Example 3
The same operation as in Reference Example A was performed, except that 0.5 g of anhydrous silicic acid (SiO ₂ / M ₂ O molar ratio was equivalent to infinity) was used as sodium silicate. As in Comparative Example 1, the asbestos yarn in the crucible was slightly shrunk and was in a stiff state. When the asbestos ribbon after the heat treatment was observed with a scanning electron microscope, the needle-like fiber structure was not lost.

実施例15
珪酸ナトリウムとして0.5 gの粉末珪酸ナトリウムJIS-1号（水ガラスを乾燥させた粉末で20重量%の含水率を有する）を使用すること以外、参考例Ａと同様の操作を行った。

Example 15
The same operation as in Reference Example A was performed except that 0.5 g of powdered sodium silicate JIS-1 (powder obtained by drying water glass and having a water content of 20% by weight) was used as sodium silicate.

Example 16
The same operation as in Reference Example A was carried out except that 0.5 g of sodium metasilicate.9 hydrate (water content 57% by weight) was used as sodium silicate.

Table 3 below summarizes the state of asbestos after heating (electron microscope or observation results by visual observation) when heat treatment was performed at various temperatures using alkali silicates having different moisture contents. Reference examples C, K, and M have already been described in Table 2, but are also described in Table 3 to facilitate comparison between the respective moisture contents.

表3の結果からは、含水率が高くなる程、石綿繊維同士の融着が顕著になり、それに伴って石綿の構造喪失度が高くなる傾向が認められる。

From the results in Table 3, it can be seen that as the moisture content increases, the asbestos fibers are more likely to be fused with each other, and the degree of asbestos structure loss tends to increase accordingly.

Reference examples O and P
Perform the same operation as in Reference Example A , except that 0.5 g of Ecolayer granules (average particle size 700 μm) ( Reference Example O ) or Ecolayer coarse particles (Average particle size 3.4 mm) ( Reference Example P ) are used as sodium silicate. It was.

In Table 4 below, the states of asbestos after heat treatment (observation results by an electron microscope) when heat treatment is performed using alkali silicates having different average particle diameters are collectively described. Reference Example C is already described in Table 2, but is also described in Table 4 in order to facilitate comparison between the average particle diameters.

表4の結果からは、平均粒子径が低い程、加熱処理後の石綿の構造喪失度が高くなる傾向が認められる。

From the results in Table 4, it can be seen that the lower the average particle diameter, the higher the degree of structural loss of asbestos after heat treatment.

Claims (4)

A method for treating asbestos-containing waste, comprising mixing and heating solid waste containing asbestos with a solid alkali silicate hydrate . _2. The processing method according to claim 1, wherein the alkali silicate has a SiO ₂ / M ₂ O molar ratio (M represents an alkali metal) of 1 to 3.5.   3. The processing method according to claim 1, wherein the alkali silicate is powdery or granular.   The processing method according to any one of claims 1 to 3, wherein the mixture is heated at a temperature of 750C to 1200C.