JPH0847636A - Water stop material for waste containing water - Google Patents

Abstract

PURPOSE:To obtain such a water stop material that when the material is used as a waterproofing layer, leaking of excess water is prevented, and that when the material is used to fill a space in a sealed container containing a waste material containing water, leaking of water from the container can be prevented, by adding and mixing sodium carboxymethyl cellulose to bentonite. CONSTITUTION:This water stop material for waste material containing water is prepared by adding and mixing sodium carboxymethyl cellulose to bentoite. The add ant. of sodium carboxymethyl cellulose is specified to 1 to 30vol.% of bentonite. The bentonite is specified to have 0.1-0.8mm average particle size. An acrylic test chamber 1 is prepared in which a simulated soln. 6 in a draining chamber 2 permeates through a space W into a test sample in a water stop chamber 3. The permeation width L of the soln. 6 in the sample is measured with time. The permeation width of this water stop material is <=1/2 compared to a sample without adding sodium carboxymethyl cellulose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water blocking material for preventing leakage of water-containing waste stored in a closed space from a closed space of excess water. More specifically, a water-stopping material used for the outer wall of the final disposal site of water-containing waste, or a water-stopping material that prevents water leakage from the airtight container when it is filled in the void of the airtight container such as a drum can. It concerns materials.

[0002]

2. Description of the Related Art Conventionally, when water-containing waste is dumped at a final disposal site, etc., bentonite is disposed as a waterproofing material for water-containing waste so that excess water in the waste does not leak outside. It may be used as a waterproof layer on the outer wall of the place.
The added bentonite swells and increases its volume, and as a result, the gap for the excess water to penetrate decreases,
Leakage of excess water is considered to be prevented.

[0003]

However, in the case where the water-containing waste contains a large amount of surplus water and the surplus water contains a large amount of salts, the general bentonite layer completely prevents leakage of the surplus water. It was difficult. The purpose of the present invention is to
Prevents excess water from leaking when used as a waterproof layer on the outer wall of a final disposal site for water-containing waste, or leaks water from a closed container when it is filled in the void of a closed container such as a drum containing water-containing waste. The present invention is to provide a waterproof material for water-containing waste that can prevent the above.

[0004]

In order to achieve the above object, the water-stopping material for water-containing waste of the present invention comprises bentonite, sodium carboxymethyl cellulose (hereinafter referred to as CMC).
Is added and mixed.

The present invention will be described in detail below. In the present invention, the amount of CMC added is preferably 1 to 30% by volume, and more preferably 5 to 10% by volume with respect to 100% by volume of bentonite.
It is more preferable that the content is% by volume. The amount of CMC added is 1
If the content is less than% by volume, the effect will appear, but the effect is not sufficient, and if it exceeds 30% by volume, the cost of the waterproofing material is increased, which is not preferable. Bentonite, which is the main component of the water blocking material for water-containing waste, is preferably granular bentonite having an average particle size of 0.1 to 0.8 mm in terms of dust control and handling with powder CMC. If the average particle size is less than 0.1 mm, problems such as dust scattering will occur and the handling will be poor, and if it exceeds 0.8 mm, it will be difficult to flow into the details. CMC, which is another component of the water blocking material of the present invention, has OH groups of cellulose as OCH ₂ C.
It is a white to pale yellow powder substituted with OONa. This substance has a wettability, is soluble in cold water, and when dissolved in water, becomes a neutral or slightly alkaline highly viscous liquid.

[0006]

When the water-containing waste has a large amount of surplus water, that is, when the water content is high, bentonite cannot swell and sufficiently fill the gaps between the particles. Further, when the surplus water contains a large amount of salts, the swelling power of bentonite is significantly reduced. In such a case, C
The molecules of MC act to increase the viscosity of excess water and prevent leakage.

[0007]

EXAMPLES Next, examples of the present invention will be described together with comparative examples in order to show specific embodiments of the present invention. The examples described below do not limit the technical scope of the present invention. <Example ^{1> Na +, K +,} Ag +, Ba 2+, Ca 2+, F
An aqueous solution simulating surplus water of a water-containing waste containing a large amount of metal salts arbitrarily selected from metal salts such as e ²⁺ , Mg ²⁺ , Cr ³⁺ , Al ³⁺ , Fe ³⁺ is as follows. Was prepared. In other words, this simulated aqueous solution contains ₂ parts of Na ₂ SO ₄ (reagent)
An aqueous solution containing 0% by weight and 0.5% by weight of Fe ₂ O ₃ (reagent), and the pH of the aqueous solution was adjusted to about 1 with NaOH.
Adjusted to 0. The specific composition of each component is as follows. Deionized water: 159 g Na ₂ SO ₄ : 40 g Fe ₂ O ₃ : 1 g NaOH: 0.09 g On the other hand, a columnar acrylic test container 1 as shown in FIG. 1 was prepared. This test container 1 is placed with its longitudinal direction horizontal, and has a waste liquid chamber 2 into which the above-mentioned simulated aqueous solution corresponding to water-containing waste is injected and a water blocking material chamber 3 filled with a test sample corresponding to a water blocking material. It is divided via the partition plate 4. A spherical container 7 for storing the simulated aqueous solution 6 is provided above the waste liquid chamber 2, and the container 7 is held by a stand 8. The simulated aqueous solution 6 in the container 7 is introduced into the waste liquid chamber 2 through the introduction pipe 9, and the height H of the simulated aqueous solution 6 in the waste liquid chamber 2 is maintained at 4 cm.

A gap W of 2 mm is formed between the partition plate 4 and the bottom of the acrylic container 1. Therefore, the simulated aqueous solution 6 in the waste liquid chamber 2 is filled in the water blocking material chamber 3 through this gap W. Configured to penetrate the test sample. The permeation width L of the simulated aqueous solution is measured. The length of the water blocking material chamber 3 that constitutes the majority of the acrylic test container 1 is 50 cm, the length of the waste liquid chamber 2 that constitutes the tip of the acrylic test container 1 is 5 cm, and the width and height of the acrylic test container 1 are 5 cm. The length is 5 cm and 6 cm, respectively.

In this example, a bentonite powder having an average particle size of 0.1 to 0.8 mm (trade name: Kuniforce NKS, manufactured by Kunimine Industries Co., Ltd.) was used as a test sample constituting a water blocking material at 100% by volume. When this is done, the commercially available CMC powder (trade name: terpolymer 3
0, manufactured by Nippon Paper Industries Co., Ltd.) was used in an amount of 1% by volume. Using the acrylic test container 1 configured as described above, the change over time of the permeation width L in which the simulated aqueous solution 6 in the waste liquid chamber 2 permeates the test sample in the water blocking material chamber 3 through the gap W was measured.

<Example 2> The permeation width in which the simulated aqueous solution penetrates into the test sample in the same manner as in Example 1 except that the addition amount of CMC powder was changed to 3% by volume as the test sample constituting the water blocking material. The change with time of L was measured.

<Example 3> The permeation width of the simulated aqueous solution permeating into the test sample in the same manner as in Example 1 except that the addition amount of CMC powder was changed to 7% by volume as the test sample constituting the water blocking material. The change with time of L was measured.

<Example 4> The permeation width of the simulated aqueous solution permeating into the test sample in the same manner as in Example 1 except that the addition amount of CMC powder was changed to 10% by volume as the test sample constituting the water blocking material. The change with time of L was measured.

<Comparative Example 1> A simulated aqueous solution was prepared in the same manner as in Example 1 except that the bentonite of Example 1 was used alone without adding CMC powder as a test sample constituting the waterproofing material. The time-dependent change of the permeation width L that permeates into the test sample was measured.

<Evaluation> Examples 1 to 4 and Comparative Example 1
The measurement results of are shown in Table 1 and FIG. 2, respectively.

[0015]

[Table 1]

In Table 1 and FIG. 2, the numerical value marked with * means that the permeation had stopped, and in Table 1, the numerical value marked with ** was permeated to the end of the container. This means that the accurate penetration width could not be measured.

As is clear from Table 1 and FIG.
It was found that the water-stopping materials (compositions) of Nos. 4 to 4 each had a permeation width of 1/2 or less as compared with the water-stopping material of Comparative Example 1 in which CMC was not added. In particular, Example 1 in which only 1% by volume of CMC was added also showed a high water-stopping ability against the simulated aqueous solution. Further, in Example 3 in which 7% by volume of CMC was added, the simulated aqueous solution stopped permeating with a permeation width of 4.4 cm after 24 hours, and in Example 4 in which 10% by volume of CMC was added, 8.8 cm after 18 hours. The penetration of the simulated aqueous solution stopped at the penetration width of. In contrast, in Comparative Example 1 in which CMC was not added, the penetration width of 50.0 cm after 72 hours, that is, the simulated aqueous solution penetrated to the end portion of the acrylic test container 1, and accurate penetration width measurement was impossible. Met.

[0018]

As described above, according to the present invention, CMC is added to and mixed with bentonite to form a waterproof material for water-containing waste, whereby the waterproof material of the present invention is used as an outer wall of a final disposal site. If used for such purposes, it is possible to prevent excess water from leaking from the water-containing waste even when the water-containing waste dumped at the final disposal site contains a large amount of salts. Further, when the water blocking material of the present invention is filled in the space of a closed container such as a drum containing water-containing waste, water leakage from the closed container can be prevented. Therefore, the use of the water blocking material of the present invention is useful for preventing leakage of concentrated waste liquid of water-containing waste containing a large amount of salt.

[Brief description of drawings]

FIG. 1 is a perspective view of a test apparatus for measuring a change over time in a permeation width of a simulated aqueous solution according to an embodiment of the present invention.

FIG. 2 is a view showing a change in permeation width with time.

[Explanation of symbols]

 1 Acrylic test container 2 Waste liquid chamber 3 Water blocking material chamber 4 Partition plate 6 Simulated aqueous solution 7 Storage device 8 Stand 9 Introducing pipe W Gap H Liquid level height L Penetration width

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masakazu Ito 1085 Nabekake, Kuroiso-shi, Tochigi Kunimine Industry Co., Ltd. (72) Mayumi Okamoto 1085 Nabekake, Kuroiso-shi, Tochigi Kunimine Industry Co., Ltd.

Claims (3)

[Claims] 1. A water stopping material for water-containing waste obtained by adding and mixing sodium carboxymethyl cellulose to bentonite. 2. The amount of sodium carboxymethyl cellulose added is 1 to 3 with respect to 100% by volume of bentonite.
The water blocking material for water-containing waste according to claim 1, wherein the water blocking material is 0% by volume. 3. The water stopping material for water-containing waste according to claim 1, wherein the bentonite has an average particle diameter of 0.1 to 0.8 mm.