JPH06114365A - Method for using ash of burned sewage sludge - Google Patents

Abstract

PURPOSE:To reuse the ash of burned sewage sludge with a high added value by a method wherein the ash is added to and kneaded with thermoplastic synthetic resin in a molten state and the resulting mass is formed into pellets, which are then rendered into article shape. CONSTITUTION:A thermoplastic synthetic resin (e.g. polyethylene) is heated into a molten state and the ash of burned sewage sludge is added thereto in such proportions that the mixture comprises 50-200 pts.wt. of the ash per 100 pts.wt. of the synthetic resin and such a mixture is kneaded uniformly by a stone mill type kneading device while a shearing force is being exerted thereon. The resulting kneaded mass is extruded into the form of a string by an extruding machine and this extrusion is cut into pellets by a cutter while being cooled with water or air. The pellets are then molded into a predetermined article shape by injection molding. As a result, the articles with various kinds of shapes can be produced, leading to the reuse of the ash of burned sewage sludge with a high added value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of using incineration ash of sewage sludge discharged in a sewage treatment process.

[0002]

2. Description of the Related Art Sewage sludge discharged in a sewage treatment process has conventionally been dehydrated and incinerated, and the resulting incinerated ash has been disposed of by landfilling, etc., but recently, the motivation to effectively use the incinerated ash has increased. There is. At present, the effective use of the incinerated ash is to granulate it into horticultural soil, or to further granulate and fire it into a lightweight aggregate, or as it is, a soil improver, a roadbed subgrade, a secondary concrete Attempts have been made to use it as a product, asphalt filler, cement raw material, etc.

[0003]

However, these conventional utilization methods are not very high in added value, and there is a demand for the development of utilization methods with higher added value. As a method of utilizing such a high added value, there is a method of blending the synthetic resin for molding as a filler. However, by simply blending the incinerated ash into the synthetic resin pellet for molding, the synthetic resin and the incinerated ash are uniformly mixed. There is a problem that it is difficult to knead and the molding process cannot be performed satisfactorily.

[0004]

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention comprises heating and melting a thermoplastic synthetic resin, adding sewage sludge incineration ash, and uniformly kneading,
It is intended to provide a method of utilizing sewage sludge incineration ash for pelletizing the obtained kneaded product and molding a molded product using the pellet.

As the thermoplastic synthetic resin used in the present invention, for example, polyethylene, polypropylene, polyvinyl chloride, polyester, thermoplastic polyurethane, polyphenylene oxide, polyphenylene sulfide, etc. All plastic synthetic resins are included.

The sewage sludge incineration ash used in the present invention preferably has a particle size of 10 μ or more and 100 μ or less, and usually 50 parts by weight or more of the incineration ash with respect to 100 parts by weight of the synthetic resin. It is mixed in a proportion of 200 parts by weight or less.

In the present invention, the above synthetic resin is melted by heating, and in that state, the incinerated ash is added in the above proportion and uniformly kneaded. For the kneading, for example, a screw type kneading device, a stone mill type kneading device, a pestle type kneading device, etc. are used, and the most suitable kneading device is a stone mill type kneading device for kneading by shear shear stress. According to the stone mill type kneading, the synthetic resin and the incinerated ash are kneaded with high homogeneity.

In the present invention, in order to improve the kneading properties of the synthetic resin and the incinerated ash, a dispersant, a chelating agent, a surfactant and the like may be used alone or in combination. Further, pigments, fillers other than incinerated ash, antioxidants, ultraviolet absorbers and the like may be appropriately mixed.

In order to pelletize the kneaded material, the kneaded material is extruded in a string shape by an extruder and cut into pellets by a water-cooled or air-cooled cutter. Usually, the kneading device is a kneading extruder integrated with the extruder. The pellets are molded into a predetermined molded product by, for example, injection molding or extrusion molding.

[0010]

In the present invention, the mixture of the thermoplastic synthetic resin and the sewage sludge incinerator ash is not directly molded, but the synthetic resin is heated and melted, and the sewage sludge incinerator ash is added and kneaded in this state, A large amount of incinerated ash can be kneaded uniformly. The pellet obtained from the kneaded product has excellent moldability.

[0011]

【Example】

[Example 1] 66% by weight of sewage sludge incineration ash with respect to polyethylene in a state where polyethylene was heated and melted at 175 ° C.
The mixture is added, kneaded by a stone mill type kneading extruder and extruded in a string shape, and cut by a cutter to obtain pellets. As a comparison, the incineration ash is simply mixed with polyethylene powder to form a mixture. The pellets and the comparative mixture were injection molded to compare moldability. As a result, the pellets showed good moldability, but the comparative mixture had poor moldability.

[Example 2] Polypropylene was melted by heating at 200 ° C, pellets were prepared in the same manner as in Example 1, and injection molding was carried out. As a result, the moldability was good.

Example 3 100 parts by weight of polyvinyl chloride was mixed with 200 phr of the incinerated ash, heated to 190 ° C. by a stone mill type kneading extruder to knead, extruded into a string shape and cut with a cutter to form pellets. Turn into. The pellets obtained show good moldability.

[0014]

Therefore, according to the present invention, various molded articles can be manufactured by adding a large amount of sewage sludge incineration ash to a thermoplastic synthetic resin, and the sewage sludge incineration ash can be reused with high added value. Become.

Front page continued (72) Inventor Manabu Tanase 37--11, Higashi-Sendai, Ogawa, Higashiura-machi, Chita-gun, Aichi Prefecture (72) Inventor Hiroki 4-14, Shibata-cho, Minami-ku, Aichi Prefecture, Espor Bird 305 (72) ) Inventor Mitsuru Nishihara 4-14, Shibata-cho, Minami-ku, Aichi Prefecture

Claims (2)

[Claims] 1. A thermoplastic synthetic resin is heated and melted, sewage sludge incineration ash is added and uniformly kneaded, the obtained kneaded product is pelletized, and a molded product is molded using the pellets. Usage of characteristic sewage sludge incineration ash 2. The method for utilizing the sewage sludge incineration ash according to claim 1, which is carried out by applying shear shear stress to knead the thermoplastic synthetic resin melt and the sewage sludge incinerator ash.