JPH11246701A - Treating method for instrumental small box comprising polyvinyl chloride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating method with high reliability and safety for a waste such as a telephone small box comprising PVC as the main component. SOLUTION: This method is for preventing the pollution of a natural environment in a way of decomposing a PVC-contg. waste in a perfectly closed system by such a treatment that comprises pulverizing a polyvinyl chloride-comprising instrumental small box and then exposing the pulverizate to a supercritical water of 400 deg.C to 600 deg.C and of 400 atmos. press. to 600 atmos. press. Desirably, the polyvinyl chloride-comprising instrumental small box is a telephone one and a starting material at ordinary temp. of the superpritical water exposed to the pulverizate is hydrogen peroxide or a mixture of hydrogen peroxide and water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating an equipment case such as a telephone case containing polyvinyl chloride to be discarded in consideration of environmental resistance.

[0002]

2. Description of the Related Art Telephones are generally used as daily communication means, and the waste of the telephone housing is currently mainly crushed and directly buried, or crushed and incinerated and incinerated ash. Will be reclaimed.

[0003] However, many telephone housings, especially those of the dial type, mainly contain polyvinyl chloride (hereinafter abbreviated as PVC), which causes environmental destruction of pollution by heavy metals and dioxins. I have.

[0004] For this reason, in the former waste disposal method, a metal compound as an additive of PVC is placed underground by a chemical reaction involving exposing the landfilled waste to acid rain or other coexisting waste. There is a risk of oozing and causing environmental pollution.

[0005] In the latter treatment method, PV
There is a danger that hydrogen chloride and highly toxic dioxin, which cause incinerator corrosion due to decomposition of C, may be generated. Therefore, a reliable method of treating telephone housing waste to solve these dangers is required. Had been requested.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in view of such a background, and an object of the present invention is to reduce waste such as a telephone housing containing PVC as a main component. An object of the present invention is to provide a reliable and safe method for processing.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a step of pulverizing an equipment housing containing PVC, and a step of pulverizing the pulverized material at 400 to 600 ° C. and 400 to 600 atm. The treatment is performed through a step of exposing to supercritical water.

In this case, the equipment housing is a telephone housing.

[0009] Further, the method includes a step of adding a neutralizing agent in the above step.

In the above-mentioned process using supercritical water, the starting material at normal temperature of the supercritical water to which the pulverized material is exposed is hydrogen peroxide or a mixture of hydrogen peroxide and water.

Further, the pulverized material is exposed to supercritical water together with a gas containing 50% or more of oxygen to be treated.

[0012]

In summary, the present invention is intended to decompose PVC-containing waste in a completely sealed system by using supercritical water, and to completely eliminate harmful substances discharged outside the system. It has the feature of being able to. This will be specifically described below.

[0013]

Embodiment 1 FIG. 1 shows the steps of an embodiment of the present invention. 0.1 g of a PVC powder 1 simulating a crushed material of a telephone housing material and 10 cc of a liquid 2 such as water are enclosed in a reaction vessel 3 composed of a closed vessel, and heated to 600 ° C. to reduce the PVC. It was exposed to an environment of supercritical water at 600 ° C. and high pressure and high pressure of 600 atm for 1 hour. After heating, the reaction vessel 3 was cooled to room temperature, and the reaction vessel 3 was opened and the contents of the reaction vessel 3 were observed. As a result, it was confirmed that the PVC powder 1 did not remain in its original form but was completely decomposed by water. In the supercritical state, the recovered liquid mainly composed of water decomposed and re-liquefied by cooling the PVC powder 1 is subjected to gas chromatography mass spectrometry (hereinafter referred to as GCM).
As a result, it was found that the PVC powder 1 was decomposed and changed to a low molecular weight organic chemical substance 4 such as benzene, phenol, naphthalene, butylphenol, and hydroquinone.

At this time, highly toxic organic chlorine compounds such as dioxin and vinyl chloride monomer were not detected at all. This experimental result means that not only waste made of PVC can be treated with supercritical water without generating harmful substances, but also valuable organic compounds can be obtained as by-products. In addition, the collected liquid showed acidity.
This means that hydrochloric acid is generated by the treatment of PVC, but it was confirmed by experiments that neutralization of hydrochloric acid was possible by adding a small amount of a neutralizing agent to water in advance.

The addition of the neutralizing agent was possible even after the treatment of PVC with supercritical water. As a neutralizing agent, sodium carbonate, sodium benzoate, calcium carbonate,
Sodium peroxide, sodium hydroxide, calcium hydroxide and the like can be used.

[0016]

[Experimental example 2] Using the same material as in Example 1, 450 ° C
And treated in a supercritical water environment at 370 atm for 1 hour. Even in this case, all of the PVC powder 1 was decomposed by water, and generation of benzene, acetic acid, phenol, butylphenol, and hydroquinone was confirmed from analysis of the recovered solution by GCMS.

[0017]

Example 3 One gram of PVC powder 1 and 17 cc of water were confined in a reaction vessel 3 and heated to 400 ° C., whereby the PVC powder 1 was placed in an environment of supercritical water at 400 ° C. and 400 atm for 1 hour. Exposed. After heating and cooling to room temperature, the reaction vessel 3 was opened and the contents of the reaction vessel 3 were observed.
A part of the VC powder 1 was decomposed by water, but a solid residue remained in part. As a result of examining constituent elements of this residue with an elemental analyzer, carbon and hydrogen were almost present, and chlorine was a slight amount (1% or less). This residue can be used as a solid fuel that generates very little chlorine compounds.

[0018]

EXAMPLE 4 0.1 g of PVC powder 1 and hydrogen peroxide or a mixture of hydrogen peroxide and water (H ₂ O ₂ : 30)
%, H ₂ O: 70%), and 8 cc of the liquid 2 was sealed in the reaction vessel 3 and heated to 600 ° C., whereby the PVC powder 1 was placed in an environment of supercritical water at 600 ° C. and 600 atm. Exposed for hours. As a result of opening the reaction vessel 3 which was cooled to room temperature after heating, the PVC powder 1 was completely decomposed, and the recovered liquid was only hydrogen chloride. The same result was obtained when 0.1 g of PVC powder, 10 cc of water and 7 atm of oxygen were confined in a reaction vessel and the same treatment was performed.

In the above embodiment, the oxygen content was 50%.
If it is contained as described above, it is not always necessary to use pure oxygen.

In each of these embodiments, the supercritical water is 400 ° C. to 600 ° C. and 400 atm.
There is no problem as long as the pressure is within the range of 00 atm. Further, the processing time may be one hour or less.

The above-mentioned supercritical water treatment of PVC can be carried out in a completely closed system. After treatment in a high-temperature and high-pressure environment, the same completely closed system is used in an environment of normal temperature and normal pressure. Can be returned. The ordinary-temperature liquid obtained after the treatment is directly guided to a usual fractionating apparatus, whereby it is possible to recover organic chemical substances generated by PVC decomposition. Waste liquid and waste gas remaining after recovery are detoxified by passing through a normal pollution prevention device, and BO
After confirming safety by measuring D, COD, PH, etc., it is possible to release it outside the closed system. Therefore, the natural environment is not polluted by the substances released outside the system.

[0022]

As described above, according to the present invention, it is possible to carry out highly reliable treatment of PVC waste which has become difficult to landfill or incinerate due to the generation of contamination by heavy metals and dioxins. In particular, since the PVC-containing waste can be decomposed in a completely closed system, the treatment and monitoring of the decomposition product can be thoroughly performed, so that there is no pollution of the natural environment by the decomposition product. Furthermore, since PVC can be converted into a valuable substance, there is an advantage that it is effective not only as a treatment of PVC waste but also as a technique for manufacturing a chemical substance using PVC waste as a raw material.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a processing step of the present invention.

[Explanation of symbols]

 Reference Signs List 1 PVC powder 2 Liquid such as water or hydrogen peroxide water 3 Closed reaction vessel 4 Organic chemical

Claims (5)

[Claims] 1. A method comprising the steps of: pulverizing an equipment housing containing polyvinyl chloride; and exposing the pulverized material to supercritical water at 400 ° C. to 600 ° C. and 400 to 600 atm. To treat equipment housing containing PVC. 2. The processing method according to claim 1, wherein the equipment housing containing polyvinyl chloride is a telephone housing. 3. The treatment method according to claim 1, further comprising a step of adding a neutralizing agent. 4. The processing method according to claim 1, wherein the starting material of the supercritical water exposed to the pulverized product at room temperature is hydrogen peroxide or a mixture of hydrogen peroxide and water. 5. The processing method according to claim 1, wherein the pulverized material is exposed to supercritical water together with a gas containing 50% or more of oxygen.