JP2008272559A - Economically detoxifying method for molded slate product of corrugated form or the like which contains asbestos - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means which efficiently, economically detoxifies a large quantity of a solid asbestos waste material in a short time. <P>SOLUTION: After slates whose asbestos contents are at most 50% are pulverized with a ceramic or stainless steel-made cylindrical ball mill, Na<SB>2</SB>B<SB>4</SB>O<SB>7</SB>or Mg<SB>2</SB>B<SB>4</SB>O<SB>7</SB>as a fusing aid is mixed the pulverized slates at a concentration of 20-35%, and then the mixture is melted at about 860°C for 3-5 hours in a gasification melting furnace 3 which is provided with a V-shaped arc plasma-type burner 4, a slag discharge 5, an exhaust gas-washing pipe 6, and a dust collector 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, the melting point of asbestos is reduced to 1520 ° C. by mixing the melting aid, and the melting point is drastically reduced. To do.

  The method of the present invention roughly breaks asbestos-containing slats, etc., and finely pulverizes the asbestos molded product with a ball mill containing stainless steel spheres of 30 mm to 50 mm in a steel drum or ceramic drum, etc. in an electric furnace or gasification melting furnace, etc. Is used to mix the melt aid and make the melt harmless in 3 to 4 hours in a relatively short time.

Problems to be solved by the invention

According to the present invention, a molded asbestos-containing slurry, in which 20 to 30% of a melting aid is mixed with powder obtained by pulverizing molded asbestos with a ball mill and completely powdered at about 800 ° C., is melted.
The melted product discharged outside the furnace, cooled and solidified is a detoxifying substance mainly composed of magnesium oxide or the like.
In addition, because of the relatively low temperature treatment, it is an extremely economical treatment method with less furnace wall consumption and less furnace material maintenance.

At the time of asbestos treatment, there was no conventional treatment method for molded asbestos, and disposal was a special industrial waste, and there was only a method of storing landfill disposal in polyethylene packaging material at a managed final disposal site.
However, there is no managed final disposal site that can handle wastes such as molded asbestos, which is said to be 47 million tons nationwide, within the next 10 years. Realization is impossible with the consent of the residents.
In order to melt the asbestos-containing processed product, a high-temperature treatment with an asbestos melting point of 1520 ° C. is required, the melting equipment is limited, and enormous disposal costs are required.

effect

  The present invention is a technology capable of detoxifying a large amount of solid asbestos molding waste in the most efficient and economical manner in a short time.

  Asbestos-containing slurry (with an asbestos content of 50% or less) is pulverized for about 10 minutes in a ceramic cylindrical or stainless steel cylindrical ball mill with a 30 mm diameter stainless steel ball. Mixing and melting in a gasification melting furnace at about 700 ° C (using temperature measurement gel gel cone) for about 2 hours, exhaust during warming uses a low pressure vacuum pump to guide the exhaust into the water in the filter bottle, As a result of qualitative analysis of the asbestos, the asbestos fiber was less than 0.005 (fiber / ml), and the asbestos fiber in the molten solid was 0. No asbestos fibers were observed in the melt solids.

It is a figure which shows the asbestos molded product powder fusion detoxification apparatus furnace.

Explanation of symbols

▲ 1 ▼ Bucket conveyor
(2) Roller conveyor
(3) Melting furnace (maximum temperature 1600 ° C, arrival time 30 minutes after ignition)
(4) V-type arc / plasma burner
▲ 5 ▼ Slag discharge ▲ 6 ▼ Exhaust cleaning pipe ▲ 7 ▼ Dust collector

Claims (2)

Asbestos waste In particular, in order to economically process a large amount of molded wave-type slate products that will be generated in the future in a large amount of harmless processing, mixing inexpensive melting aids, relatively low temperatures (about 860 ° C) 3 It is a technique for detoxifying the melt within 5 hours and is a safe treatment method in which asbestos fibers are not scattered at all during disposal.
That is, asbestos molded products (mainly corrugated slats) are pulverized to form powdered asbestos, and 20 to 35% of the melting aid is mixed to a heat-detoxified solid material at about 860 ° C. A technique characterized by mixing and using 20 to 35% of melting aid Na ₂ B ₄ O ₇ or Mg ₂ B ₄ O ₇ in powder asbestos.
For making powdered corrugated plates into powder, a stainless steel 18x8Ni ball with a diameter of 20 to 30 mm is placed in a steel sealed cylindrical container and betted safely in a short time (10 to 30 minutes).

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