JP3085958B2 - Asbestos melting process - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for melting asbestos, which has recently become a problem as a carcinogenic substance. In addition, asbestos means chrysotile [Mg ₃ Si ₈ O ₅ (OH) ₄ ], crocidolite [Na ₂ Fe ₅ Si ₈ O ₂₂ (OH) ₂ ], amosite [(FeMg) ₆ S
i ₈ O ₂₂ (OH) ₂ ].

[Prior Art] Conventionally, asbestos treatment is mainly landfill disposal, and in recent years, melting treatment has begun to be performed in an electric furnace in part.

[Problems to be solved by the invention]

However, the landfill process may cause secondary pollution, and the melting process using an electric furnace requires a large amount of expensive electricity, so the melting process cost becomes enormous, and the processing cost needs to be as low as possible. There was a major drawback in waste disposal.

An object of the present invention is to make it possible to greatly reduce the cost of asbestos melting treatment, and to devise means for that purpose to be effective in preventing secondary pollution.

[Means for solving the problem]

The characteristic means of the present invention is a high-temperature hearth in which a dewatered cake of a water treatment sludge is mixed with asbestos, the water content of the mixture is adjusted, the mixture is molded, and the molded mixture is formed of a carbon-based combustible material. And melts by heating. The operation and effect are as follows.

(Operation)

The dewatered cake of water treatment sludge has a water content of 75-80%,
When it is kneaded, it becomes similar to water and is more sticky than water, making effective use of it as a binder, forming asbestos with a dewatered cake of water-treated sludge, and shaping the formed mixture with coke etc. Are melted in a high-temperature hearth of a carbon-based combustible material while scattering by combustion exhaust gas is sufficiently suppressed.

In other words, a high-temperature hearth-type melting furnace whose operating cost is much lower than that of an electric furnace can convert asbestos into a harmless molten material, and can greatly reduce asbestos processing costs.

In addition, since asbestos is melted in a molded state using water treatment sludge, which is essentially waste, it is possible to avoid the inconvenience of asbestos being externally released along with the combustion exhaust gas during the melting process, and to reduce secondary pollution. Can be sufficiently prevented, and
It is possible to sufficiently suppress an increase in processing costs caused by the molding binder.

To explain further, for example, molding with a special binder such as water glass increases the cost required for the binder, but if water treatment sludge, material cost is unnecessary, and
When molding with water, about 20 to 30% by weight of asbestos water must be added, so that the latent heat loss of evaporation increases in the melting process and the melting rate decreases, which increases the cost of the melting process. Since the treated sludge is sticky, it is only necessary to reduce the water content of the mixture of asbestos and sludge to about 10% by weight, and the cost of the melting treatment can be reduced.

〔The invention's effect〕

As a result, the asbestos melting process that is not only safe but also economical can not only be carried out with sufficient saving of accounting process, but also to prevent secondary pollution sufficiently. It was established.

〔Example〕

 Next, an example is shown with a drawing.

Water treatment sludge generated during purification treatment of sewage, tap water, industrial wastewater, etc. is treated with a dehydrator (1) to obtain a water content of 75 to 75%.
Make about 80% dehydrated cake.

The dewatered cake of asbestos and water-treated sludge is adjusted so that the water content of the mixture of asbestos and sludge is about 10% by weight, and is sufficiently stirred and mixed by the mixer (2).

The mixture from the mixer (2) is subjected to a molding treatment in a molding machine (3), and the molding mixture is heated and melted in a melting furnace (4) in a high-temperature hearth formed of a carbon-based combustible material such as coke.

At this time, the water treatment sludge effectively acts as a binder, and a sufficiently strong molded product can be obtained, and the scattering of asbestos in the melting furnace (4) can be sufficiently suppressed.

(Another embodiment)

 Next, another embodiment will be described.

The mixing ratio of the dewatered cake of the water treatment sludge to asbestos can be appropriately selected in accordance with the water content, the tackiness, and the like of the dewatered cake.

The dehydrator (1) and the mixer (2) to be used can be appropriately selected from known ones.

The shape and size of the molding mixture can be appropriately changed, and the molding machine (3) to be used can be appropriately selected from known ones such as a screw type extrusion molding machine.

It does not matter how the slag from the melting furnace (4) is treated.

[Brief description of the drawings]

 The drawing is a flow sheet showing an embodiment of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-237984 (JP, A) JP-A-51-52678 (JP, A) JP-A-62-212260 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B09B 3/00 F23G 5/00 115 F23G 7/00

Claims (1)

(57) [Claims] 1. A dewatered cake of water-treated sludge is mixed with asbestos, the water content of the mixture is adjusted, the mixture is molded, and the molded mixture is supplied to a high-temperature hearth made of a carbon-based combustible material. Melting process of asbestos which is heated and melted.