JP3963407B2 - Refractory for ash melting furnace - Google Patents

Description

【００１３】
【発明の効果】
本発明は、溶融スラグと反応してスラグの粘性を上げて、耐火物中へのスラグ浸透を止める効果がある炭化けい素と中高温強度を出すためのアルミナとを組み合わせて、炭化けい素５０〜９０重量％、アルミナ５〜４５重量％およびカーボン０．１〜２０重量％を含む材質のプレキャストブロックを灰溶融炉用耐火物として用いることにより、長寿命で安定した操業を可能にした。[0001]
BACKGROUND OF THE INVENTION
The present invention provides, for example, the bottom or side wall of an ash melting furnace that is used when melting slag by applying heat such as plasma to reduce the volume of incinerated ash and fly ash discharged from a garbage incinerator. It relates to refractories for ash melting furnaces used for lining, tuyere, firewood, ceilings, etc.
[0002]
[Prior art]
Conventionally, as refractories for ash melting furnaces, there are used methods in which bricks such as carbon, silicon carbide, and high alumina are arranged, and methods in which silicon carbide castables are poured locally.
[0003]
[Problems to be solved by the invention]
Conventional refractories for ash melting furnaces have the following problems.
That is, carbon bricks are easily oxidized and are not used for slag interfaces, ceilings, or walls. In addition, joint melting loss is large.
[0004]
Furthermore, silicon carbide bricks have large joint damage and are easily oxidized.
High-alumina bricks are inferior in corrosion resistance and have a large joint damage.
[0005]
In addition, since silicon carbide castables are constructed locally, they contain a large amount of added water and have low strength, so damage due to wear and the like is significant.
[0006]
[Means for Solving the Problems]
The present inventors have result of various studies, silicon carbide 5 0 90% by weight as ash melting furnace refractories, (excluding β- alumina) alumina 5-45 wt% and carbon 0.1 to 20 weight % Of the precast block made of a material containing% is provided on the lining of the side wall of the ash melting furnace, etc., enabling a long life and stable operation. That is, it includes 50 to 90% by weight of refractory silicon carbide for ash melting furnaces for garbage incinerators according to the present invention, 5 to 45% by weight of alumina (excluding β-alumina), and 0.1 to 20% by weight of carbon. It has a material and is formed of a precast block with a surface that contacts the molten slag.
Silicon carbide contained in the precast block is characterized in that it reacts with molten slag to increase the viscosity of the slag and to stop slag penetration into the refractory.
[0007]
(Reason for limiting the amount of silicon carbide added) Silicon carbide reacts with the molten slag to increase the viscosity of the slag, and has the effect of stopping slag penetration into the refractory. 5 0 not enough to raise the slag viscosity less than wt%. Silicon carbide is easily becomes reacts with oxygen in the air to silica as _{SiC + 2O 2 → SiO 2 +} CO 2, in this case there is a risk that there would be no effect of increasing slag viscosity.
[0008]
(Reason for limiting the amount of alumina added) Alumina functions as a sintered material in order to provide medium-high temperature strength. If it is less than 5% by weight, the sintering function cannot be sufficiently exhibited, and the strength at medium and high temperatures is low. Alumina is inferior in heat spalling resistance, and when it exceeds 45 % by weight , this tendency appears remarkably. Therefore, the addition amount is 5 to 45 % by weight.
[0009]
(Reason for limiting the amount of carbon added)
Carbon has poor wettability with molten slag and is excellent in resistance to slag melting and infiltration. The effect does not appear at 0.1% by weight or less. If it is 20% by weight or more, damage due to oxidation is significant.
[0010]
(Function)
Combining silicon carbide that reacts with molten slag to increase the viscosity of the slag and stop the penetration of slag into the refractory, and carbon with poor wettability between alumina and molten slag to produce medium and high temperature strength By making a precast block, construction defects due to on-site casting were eliminated, enabling stable operation with a long life of the ash melting furnace.
[0011]
[Example 1]
After predetermined moisture was added to the formulation shown in Table 1 and kneaded, casting was performed while applying vibration to the mold. After 24 hours, the frame was removed, dried at 110 ° C. for 24 hours, and then subjected to a hot bending test at 1500 ° C. and an oxidation resistance test at 1500 ° C. for 10 hours. After performing an erosion test for 12 hours by the rotating drum method, 20 cycles of air cooling and heating were performed to obtain a spalling test. It shows in Table 1 with a result.
[Table 1]

[0013]
【The invention's effect】
The present invention combines silicon carbide, which has the effect of increasing the viscosity of slag by reacting with molten slag and stopping slag permeation into the refractory, and alumina for producing medium-high temperature strength. By using a precast block made of a material containing 0 to 90% by weight, alumina 5 to 45 % by weight and carbon 0.1 to 20% by weight as a refractory for an ash melting furnace, a long-life and stable operation was made possible.

Claims (1)

Formed with a precast block having a material containing 50 to 90% by weight of silicon carbide, 5 to 45% by weight of alumina (excluding β-alumina) and 0.1 to 20% by weight of carbon and having a surface in contact with the molten slag. Has been
The silicon carbide contained in the precast block, by raising the viscosity of the slag to react with the molten slag, ash melting furnace for waste incinerator, characterized by having the effect of stopping the slag penetration into the refractory in Refractories for use.