JP2001191051A - Method for manufacturing dechlorinated waste plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contribute to the recycling of waste plastic by removing chlorine from the waste plastic such as vinyl chloride with a simple process to produce plastic fuel, a blast furnace raw material or a calmative for making steel. SOLUTION: Hydrogen chloride generated by the pyrolysis of the vinyl chloride is fixed as a metallic salt such as calcium chloride, magnesium chloride by pulverizing the waste plastics, adding and mixing a metal oxide or a metallic carbonate such as calcium oxide, magnesium oxide, calcium carbonate, magnesium carbonate in a quantity equal to or above, preferably 10 times the equivalent of contained chlorine and melding at 180-350 deg.C. Generated hydrochloric acid is almost completely captured by the presence of the excess metal oxide, the metallic carbonate and the fear of the corrosion with hydrochloric acid in a succeeding process is eliminated and the waste gas is sufficiently treated with a simple system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a form in which chlorine is removed from waste plastics containing vinyl chloride by a relatively simple process, and no dioxins are produced or flue corrosion due to hydrogen chloride generated is prevented. Boiler fuel,
It produces blast furnace raw materials or steel calming agents and contributes to the recycling of waste plastics.

[0002]

2. Description of the Related Art Conventionally, in order to remove vinyl chloride mixed in waste plastics, a physical separation method using X-rays, or a method in which a mixture is melted and pyrolyzed, and hydrogen chloride gas generated is separated by alkali washing. One of the ways was taken.

[0003]

The physical separation method using X-rays is, for example, a waste pet (PET; Polyethyl).
enterephthalate) It is used to remove vinyl chloride bottles mixed into bottles. However, this method is a process for the purification of PET, and the separation performance is poor in spite of the high cost of the equipment, and in fact, it is actually necessary to use manual separation in combination. The method based on melt pyrolysis is used, for example, for refining waste plastic for blast furnaces. However, this method requires expensive equipment in post-processing such as alkali washing or exhaust gas treatment of hydrogen chloride gas generated by thermal decomposition, and the cost is low for recycling waste plastic even if hydrogen chloride is recovered. There is a problem that it is too expensive.

[0004]

According to the present invention, waste plastics are pulverized, and metal oxides such as calcium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, etc., metal carbonates and the like having an equivalent of chlorine or more are contained. Is added and mixed, and the mixture is melted at 180 to 350 ° C. and hydrogen chloride generated by thermal decomposition of vinyl chloride is fixed as a metal chloride such as a calcium salt or a magnesium salt in a plastic melt. By using the metal oxide, metal carbonate, etc. in an amount equal to or more than the equivalent of chlorine contained, desirably about 10 times, hydrogen chloride generated by melt pyrolysis after mixing can be almost completely captured by this excess. There is no fear of hydrochloric acid corrosion in the subsequent steps, and simple treatment of exhaust gas is sufficient. The metal chlorides immobilized inside the molten waste plastic are not harmful in the use of the present invention, i.e., in boiler fuels, blast furnace raw materials or steelmaking sedatives, and the residual metal oxides and metal carbonates Etc. are not only harmless in this application, but also rather useful materials such as protection of furnace walls for steelmaking applications.

[0005]

The plastic manufactured in this manner is used not only for boiler fuel but also for combustion in a blast furnace.
Used as a reducing gas by gasification. It is also very effective as a calming agent for steelmaking in which conventional papermaking sludge is used.

[0006]

Example 1 A waste magnetic tape made of PET containing about 0.5% chlorine was used because a vinyl chloride adhesive was used.
Tons, 3 tons of waste polypropylene film are crushed to under 10 mm and mixed with 600 kg of calcium carbonate,
The mixture is melted at 260 ° C. in an externally-heated extruder and extruded in a shape of 40 mm L × 50 mm W × 30 mm H to obtain a cut-shaped plastic molded product.
3.6 tons were obtained. When the cut rice cake-shaped plastic was put in a converter as a slag forming sedative, the forming was immediately sedated. Further, the cut rice cake-shaped plastic was crushed into a lump of about 10 mm by a crusher, and a combustion test was performed using the crushed material as a boiler fuel. As a result, no hydrochloric acid was generated, and combustion was confirmed without any problem.

[0007]

According to the present invention, massive waste plastics produced by immobilizing chlorine from metal wastes mixed with vinyl chloride with metal chlorides are manufactured as boiler fuel,
It can be used as a reducing agent for blast furnaces, and also as a calming agent for steelmaking. In these applications, there is no generation of hydrogen chloride, no flue corrosion, no fear of generating dioxins,
Ideal waste plastic recycling product

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B29K 105: 26 B09B 3/00 303E 304P

Claims (1)

[Claims] 1. A waste plastic containing vinyl chloride is pulverized, and a metal oxide such as calcium oxide, magnesium oxide, calcium carbonate, magnesium carbonate or the like, a metal carbonate, a metal hydroxide, or the like, which has an equivalent or more of the contained chlorine. One or more minerals such as dolomite are added and mixed.
Hydrogen chloride, which is melted at 350 ° C. and produced by thermal decomposition of vinyl chloride, is fixed in molten plastic as metal chlorides such as calcium chloride and magnesium chloride, and the melt is molded by an extruder method, a plunger method, or the like. Alternatively, a method for producing dechlorinated waste plastics which is molded and pulverized and used as boiler fuel, blast furnace raw material, or a steelmaking calming agent.