JPH11192469A - Treatment of plastics, and solid fuel and reducing agent for ore obtained by the treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plastic treated material easy to pulverize by heating plastics at a specified temperature, then removing low boiling point components, and cooling and solidifying the residue. SOLUTION: In the case that solid fuel is produced from waste plastic and container packing material contained in municipal refuse, industrial waste, or the like, and waste plastics generated in a disassembling process of electric products, automobiles, or the like, when pulverizing the plastics, it is heated to a temperature of 150 deg.C or more, thereby cutting a part of bonding of the plastics by heat, or disentangling the entanglement of plastic molecules. After that, by removing decomposed products of the plastics and low boiling point components such as a plasticizer in the plastics, a plastic treated material easy to pulverize is obtained. The treated material obtained by removing the low boiling point components is preferably cooled and solidified from treating temperature at the removal of the low boiling point components to 100 deg.C or less within 10 min after start of cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating plastic from which a plastic product that can be easily pulverized can be obtained, and a solid fuel and an ore reducing agent obtained by the treatment method. The present invention relates to a plastic processing method capable of converting a plastic containing chlorine-containing plastics such as vinyl into a plastic processing product containing substantially no chlorine, and a solid fuel and an ore reducing agent obtained by the processing method.

[0002]

2. Description of the Related Art As one solution to the effective use of waste plastics in recent years, a method of producing a solid fuel from waste plastics can be considered. This is because the plasticity of the plastic is significantly improved by pulverization, and can be a useful fuel resource.

A conventional technique for converting plastic to a solid fuel is described in, for example, "Plastics Vol. 47, No. 7, p60".
As described in the above, plastics are directly pulverized with a pulverizer. However, in this method, a hard plastic must be ground to a particle size of 1 to 2 mm, and this grinding requires a lot of time and expense, and it is difficult to grind a fibrous or film-like plastic. Therefore, it has to be separately pulverized after the solidification, which causes a problem that the process becomes complicated.

Furthermore, plastics containing chlorine such as polyvinyl chloride generate dioxin, which is a harmful substance, when incinerated, and when heated, generate hydrogen chloride gas and corrode containers and pipes. Apart from plastic, it is necessary to dehydrochlorinate by heat treatment or the like.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and enables processing even when films are mixed, and also allows simultaneous dehydrochlorination.
An object of the present invention is to provide a plastic processing method capable of obtaining a plastic processing product that can be easily pulverized, and a solid fuel and an ore reducing agent by the processing method.

[0006]

Means for Solving the Problems In the course of studying various methods to achieve the above-mentioned object, the present inventors heated plastics to a temperature of 150 ° C. or more.
Part of the plastic bond is broken by heat or the entanglement of the plastic molecular chains is loosened, and after the above-mentioned heating, low boiling components such as decomposition products of the plastic and plasticizer in the plastic are removed. As a result, it has been found that it is possible to obtain a plastic processed product that is easily crushed.

When two or more different kinds of plastics are used in combination, melting and mixing of the different kinds of plastics occur in the heat treatment step, the arrangement of the polymer chains becomes irregular, and the resulting treated material becomes brittle. It was found that a plastic processed product that could be easily crushed was obtained. Furthermore, according to the present invention, dehydrochlorination can be simultaneously performed in the heat treatment step, and chlorine compounds such as hydrogen chloride can be removed from the plastic processed material in the low boiling point component removing step. There is no generation of dioxin or hydrogen chloride gas when used as.

[0008] That is, the first invention uses plastic.
This is a plastic processing method characterized by removing low-boiling components after heating at a temperature of 150 ° C. or higher, and cooling and solidifying. The second invention is a method for treating plastic, which comprises subjecting the plastic to heat treatment at a temperature of 150 ° C. or higher, removing low-boiling components, cooling, solidifying, and then pulverizing.

In the first and second aspects of the present invention, the treated product obtained by removing the low-boiling components is cooled to 100 ° C. or less within 10 minutes after the start of cooling from the processing temperature at the time of removing the low-boiling components. It is preferable to cool and solidify. In the first and second aspects of the present invention, it is preferable that the plastic is a chlorine-containing plastic.

In the first and second aspects of the present invention, it is more preferable that the plastic is a mixture containing two or more types of plastics. Further, in the first and second inventions described above, it is more preferable that the plastic is a mixture containing chlorine-containing plastic and at least one other plastic different from the chlorine-containing plastic.

Further, in the first and second aspects of the present invention, it is preferable to use a distillation method as a method for removing the low-boiling components, and furthermore, as the distillation method, it is preferable to use an atmospheric pressure of an object to be treated. It is more preferable to use a vacuum distillation method under a pressure condition of ≤ (atmospheric pressure-500 Torr). Further, in the above first and second inventions, after heat-treating the plastic at a temperature of 150 ° C. or more and / or after removing low-boiling components, insoluble components in the treated product are removed, After that, it can be cooled and solidified,
More preferred.

A third aspect of the present invention is the first aspect of the present invention,
A solid fuel which is a plastic processed product obtained by the method for processing a plastic according to the present invention. A fourth invention is a reducing agent for ore, which is a processed plastic product obtained by the method for processing a plastic according to the first invention or the second invention.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below in the order of the plastic, heat treatment step, low boiling point component removing step, insoluble matter removing step, cooling, solidifying step and pulverizing step according to the present invention. . [Plastic:] In addition to virgin plastics, plastics that are subject to the present invention include waste plastics and container packaging materials contained in municipal waste and industrial waste, and waste generated in the process of dismantling electric appliances and automobiles. Plastic is exemplified.

[0014] Specifically, all materials such as polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, polycarbonate, nylon, and other thermoplastic resins and thermosetting resins are applicable. It is also possible to use only one of the plastics,
It is also possible to use more than one kind in combination.

In the method of the present invention, it is not necessary that all the plastics are in a molten state and have a low molecular weight.
Even if some infusible matter such as a thermosetting resin remains in the obtained solid fuel, it is sufficient if there is no significant obstacle to pulverization and the like. In the present invention, by using different types of plastic mixtures, in the heat treatment step described later, melting of different types of plastics, mixing, etc. occur, the arrangement of polymer chains becomes irregular, and the resulting plastic processed product becomes brittle.
It becomes easier to grind the processed plastic.

In particular, according to the present invention, a halogen element such as chlorine contained in a plastic becomes a hydrogen halide such as hydrogen chloride during processing and is easily separated, so that a chlorine element such as polyvinyl chloride or polyvinylidene chloride is used. May be contained. Therefore, according to the present invention, it is not necessary to sort waste plastic, which is also very advantageous.

That is, when the treatment is performed in accordance with the method of the present invention, a plastic processed product substantially containing almost no halogen element such as chlorine can be obtained. The shape and size of the plastic used in the present invention may be roughly pulverized, and a size of about 10 cm square is sufficient.In general, waste plastic does not need to be pulverized again, and is in a state of being recovered. And film-like, sheet-like and fibrous plastics can be treated as they are.

[0018] The finer crushing makes heating easier,
The cost of crushing increases accordingly. [Heat treatment step:] The method of heating the plastic to a temperature of 150 ° C. or higher is not particularly limited. That is, any method such as a method of simply heating a container containing plastic or a method of mixing plastic and a high-temperature medium in the container may be used.

When a high-temperature medium is used, examples of the high-temperature medium include hot air and hot sand. When a solid high-temperature medium such as hot sand is used, a solid-liquid separation step such as a sedimentation separation method or a filtration method may be incorporated in a subsequent step. Processing temperature is 150 ℃
That is all. It is thought that heating plastic at a temperature of 150 ° C or higher may break some of the plastic bonds by heat or loosen the entanglement of the plastic molecular chains, weakening the strength of the solid obtained after cooling. Further, when different types of plastics are melted and mixed, the arrangement of polymer chains becomes irregular, the resulting plastic processed product becomes brittle, and pulverization becomes easy.

If the processing temperature is lower than 150 ° C., the hardness of the plastic processed product obtained after cooling is almost the same as that of the original plastic, and it is difficult to pulverize the plastic. Is likely to occur more,
The pulverizability of the plastic processed product obtained after cooling is improved. On the other hand, if the treatment temperature is too high, the gasification or oilification of the plastic lowers the yield of the solid after cooling.

Therefore, the processing temperature is specified to be 150 ° C. or higher, but the upper limit is preferably 450 ° C., more preferably 200 to 400 ° C., and further preferably 250 to 380 ° C. Plastic depends on its composition,
Above about 140 ° C, it becomes a molten state, and if it is preferably stirred and mixed at this time, the homogeneity of the obtained substance is increased,
Further, the decrease in the toughness described above is also promoted, and the pulverized plastic product obtained after cooling becomes easier.

After the temperature of the plastic is raised to 150 ° C. or higher, it is preferable to maintain the temperature at 150 ° C. or higher for a certain period of time. The longer the retention time, the more reliable the dehydrochlorination can be performed, and the more the processed plastic obtained after the removal of the low boiling components becomes brittle. Problems such as a decrease in the yield of the solid and a decrease in the processing capacity of the facility occur.

The preferred holding time is between 10 minutes and 6 hours,
More preferably, it is 20 minutes to 3 hours. During the heat treatment, it is preferable to perform stirring or bubbling using air or an inert gas because dehydrochlorination is efficiently performed. [Low Boiling Component Removal Step:] After the completion of the above-described heat treatment, the plastic is subjected to removal of the low boiling component, followed by cooling to obtain a lump of the processed plastic.

In the process of removing low boiling components, low boiling components such as plasticizers, reaction products such as hydrogen chloride, and decomposition products of plastics in the plastic are removed, and the pulverizability of the obtained processed plastic is reduced. improves. In addition, if a liquid component at room temperature remains in the processed plastic, coagulation may occur after pulverization or the pulverizability may be reduced. Therefore, low boiling components are removed.

For the removal of the low-boiling components, a distillation method, a drying method and the like can be used. In the case of performing distillation, simple simple distillation is also possible, and either a batch method or a continuous method may be used. In any case, the pitch-shaped bottom obtained after distillation can be extracted by an arbitrary method and cooled to obtain a target plastic processed product.

The distillation temperature is preferably from 150 to 400 ° C. The distillation temperature is more preferably from 200 to 400 ° C, even more preferably from 250 to 380 ° C. As a distillation method,
Either normal pressure distillation or reduced pressure distillation may be used, but reduced pressure distillation is preferred because the efficiency of removing low-boiling components is higher, and reduced pressure distillation is performed under the condition of atmospheric pressure of the object to be treated ≦ (atmospheric pressure−500 Torr). It is more preferable to use

When the drying method is used, it is possible to use a method of storing in a container of an arbitrary size and treating in a kiln. The processing temperature for the drying method is 150 to 400
C is preferred. The treatment temperature in the case of the drying method is more preferably from 200 to 400 ° C, further preferably from 250 to 380 ° C.

In the present invention, it is possible to remove low-boiling components by a spray drying method. In this case, 150-40
It is preferred to spray the plastic at a temperature of 0 ° C.
If the temperature of the step of removing the low-boiling components is too low, it becomes difficult to remove the low-boiling components. Conversely, if the temperature is too high, gasification or oiling of the plastic occurs, and the yield of solids after cooling decreases. .

The low-boiling components removed in this step are low-molecular-weight components obtained by decomposing the plastic, additives such as a plasticizer in the plastic, and reaction products such as hydrogen chloride.
The temperature at the time of removing the low boiling component may be the same as or different from the temperature of the heat treatment step. If the temperature at the time of low boiling point component removal is higher than the temperature of the heat treatment step, it is easy to remove the low boiling point component,
preferable.

[Step of Removing Insolubles:] In the present invention, it is more preferable to remove insolubles from the processed material after the above-mentioned heat treatment step or after the step of removing low boiling components or both steps. When a solid-liquid separation step such as a centrifugal separation method, a stationary separation method, or a filtration method is incorporated as a post-step of the heat treatment step and / or a post-step of removing the low-boiling-point component, glass,
It can be processed even if it contains an inorganic substance such as metal or paper, and for example, can also process bottles with a metal cap attached.

In addition, by removing the insoluble matter, inorganic substances such as metals are removed, and not only the pulverization in the subsequent step is facilitated, but also a plastic processed product having a small chlorine content is obtained. That is, when dechlorinating a chlorine-containing plastic such as polyvinyl chloride, a carbide is easily generated, and a chlorine component is easily contained in the carbide.
By removing insoluble components in the post-process of the heat treatment process and / or the post-process of removing the low boiling components, the chlorine content in the obtained plastic processed product can be further reduced.

[Cooling and solidifying step:] The treated material after the removal of the low-boiling components is cooled to obtain a solidified plastic treated material. The cooling method and the cooling rate are not particularly limited, but the higher the cooling rate, the easier the obtained plastic processed product is to be crushed. In the present invention, it is preferable that the cooling time from the temperature at the time of removing the low-boiling components to a temperature of 100 ° C. or lower be within 10 minutes from the start of cooling.

[Pulverizing step:] In the present invention, cooling,
It is preferable to pulverize the lump of the solidified plastic processed product to a predetermined size. Grinding at this stage is much easier than grinding untreated plastic. Therefore,
It can be crushed by any type of crusher, for example, a jaw crusher, a roll crusher, a ball mill, a centrifugal mill and the like can be used.

The particle size after grinding may be determined according to the object to be used. If the particle size is adjusted to a predetermined particle size, for example, an ore reducing agent such as iron ore, that is, an original material such as a reducing agent for a blast furnace is used. It can be used as fuel or combustion fuel for boilers and kilns. Furthermore, the plastic processed product obtained by the processing method of the present invention is excellent in pulverizability, in addition to the above-mentioned applications, solid fuel excellent in flammability with fine powder,
Can be used as a reducing agent.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. (Example 1) A polyethylene (film), polypropylene (plate), polystyrene (plate), and polyethylene terephthalate (fibrous) were placed in a stainless steel reactor having an internal volume of 5 liters to a length of about 10 cm square or about 10 cm, respectively. 300 g of each of the cut pieces was added, and heating was started by a heater on the outer wall of the reactor.

In addition, the component analysis value of the mixture of the above four kinds of plastics in the above-mentioned compounding amount is as follows: C: 81 wt%,
H: 11 wt%, O: 8 wt%. When the temperature inside the reactor exceeded 180 ° C. after the start of heating, stirring was started because most of the plastic was melted, and finally the temperature was raised to 330 ° C. and maintained at that temperature for 2 hours.

Next, vacuum distillation at 50 Torr (absolute pressure) was carried out at the same temperature for 2 hours, and thereafter, the mixture was cooled to room temperature to obtain a brown solid. When 5 g of the obtained brown lump solid was charged into a rotary blade type pulverizer and pulverized, it was easily pulverized,
A pulverized solid having an average particle size of 1 mm was obtained in a grinding time of 20 seconds.
The type and shape of the plastic used in this example,
Table 1 shows the test results such as the dimensions, the amount charged to the reactor (: addition amount), other processing conditions, the component analysis values of the obtained lump, and the results of the pulverization test.

(Examples 2 to 12, Comparative Examples 1 and 2) Example 1
And plastics with different blending amounts (Chemical analysis value of mixture: C: 73 wt%, H: 9 wt%, O: 7 wt%, Cl: 11 wt%)
%) And the same conditions as in Example 1 were used except that the heat treatment conditions and the conditions for the components having low boiling points were changed.

The obtained solid mass was pulverized using the same pulverizer as in Example 1, and the pulverization time and average particle size were measured.
Test results such as the type, shape and size of the plastic used in the present example and the comparative example, the input amount (: addition amount) to the reactor, other processing conditions, the component analysis value of the obtained lump, the pulverization test result, and the like. Are shown in Table 1.

(Example 13) Polyvinyl chloride (analysis value of component C: 41 wt%, H: 3 wt%, O: 0 wt%, Cl: 56 wt%)
Was treated in the same manner as in Example 1 under the conditions shown in Table 1, and the obtained lump-shaped plastic processed product was evaluated. Table 1 shows the component analysis values and the pulverization test results of the obtained lump.

Example 14 The procedure of Example 2 was repeated, except that the treated product after the removal of the low-boiling components was subjected to hot filtration at the same temperature as the temperature at the time of the removal of the low-boiling components to remove solid insoluble components. After obtaining the treated product in the same manner as in 2, the sample was cooled and solidified. Table 1 shows the component analysis values and the pulverization test results of the obtained lump.

(Comparative Example 3) Polyethylene (film), polypropylene (plate), polystyrene (plate), polyvinyl chloride (plate), polyethylene terephthalate (fibrous) cut into about 1 cm square or about 10 cm length Each 10 g of the crushed product was put together in a rotary blade type crusher, and crushing was attempted.

However, the film-like or fibrous plastic was entangled with the rotary blade and could not be crushed. From the above results, the plastic processed product obtained by the processing method of the present invention is easily pulverized and has a low chlorine content, and is intended for applications such as solid fuel for boilers and kilns, and reducing agents for iron ore. It turns out that it is excellent.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

According to the present invention, various problems in the conventional method of directly pulverizing green plastic are greatly improved. That is, according to the present invention, the following excellent effects can be obtained. : For example, direct pulverization of plastic into 1 to 2 mm square is unnecessary, and preliminary pulverization to about 10 cm square is sufficient.

The plastic processed product obtained by cooling and solidifying is brittle and is extremely easy to pulverize. : Film and fibrous plastics can be processed simultaneously with other plastics. : Chlorine-containing plastics such as polyvinyl chloride can be treated at the same time.

The processed plastic product obtained by the method of the present invention is excellent in pulverizability, can obtain a fine powder substantially containing no chlorine, and is used as a non-polluting fuel, a reducing agent, etc. excellent in flammability. be able to. Further, according to the present invention, since continuous processing can be performed, it is not necessary to use a complicated and expensive apparatus, and if a large reaction vessel is used, a large amount of processing can be performed, and economic efficiency is excellent. ing.

Claims (9)

[Claims] 1. A method for treating a plastic, comprising heating the plastic at a temperature of 150 ° C. or higher, removing low-boiling components, cooling and solidifying the plastic. 2. After the plastic is heat-treated at a temperature of 150 ° C. or higher, low boiling components are removed, and the plastic is cooled and solidified.
A method for treating plastic, which comprises crushing. 3. The treated product obtained by removing the low-boiling components is cooled and solidified to 100 ° C. or less within 10 minutes after the start of cooling from the processing temperature at the time of removing the low-boiling components. 3. The method for treating plastic according to 1 or 2. 4. The method according to claim 1, wherein the plastic is a chlorine-containing plastic. 5. The method according to claim 1, wherein the plastic is a mixture containing two or more plastics.
A method for treating plastic according to any one of claims 1 to 3. 6. A plastic treatment according to claim 1, wherein said plastic is a mixture containing chlorine-containing plastic and at least one other plastic different from said chlorine-containing plastic. Method. 7. After heating the plastic at a temperature of 150 ° C. or higher and / or after removing low boiling components,
The method for treating plastic according to any one of claims 1 to 6, wherein insolubles in the treated material are removed, and thereafter, the material is cooled and solidified. 8. A solid fuel which is a plastic processed product obtained by the method for processing plastic according to claim 1. 9. A reducing agent for ore, which is a processed plastic product obtained by the method for processing a plastic according to any one of claims 1 to 7.