What refractory materials should be used in various parts of the sodium silicate melting furnace?
Refractory materials for sodium silicate melting furnace
Refractory materials generally refer to inorganic non-metallic materials with a refractoriness of more than 1580 ℃. It includes natural ores and various products made through certain processes according to certain purpose requirements. It has certain high-temperature mechanical properties and good volume stability. It is a necessary material in various sodium silicate melting furnaces.
The working temperatures of various parts of the sodium silicate melting furnace are different, and the requirements for refractory materials in various parts are also very different. In order to extend the service life of the sodium silicate melting furnace, it is recommended that refractory materials be selected and used in various parts of the sodium silicate melting furnace according to the following methods.
01 Melting section
Kiln arch (big arch): There is a large amount of high-temperature alkali vapor in this part, and the operating temperature is 1500~1600℃. It is recommended to use high-quality silica bricks.
Bricks for arch foot: There is scattering of powder and flow down after the arch top is melted in this part. The operating temperature is 1500~1600℃. It is recommended to use high-quality silica bricks and low creep zircon bricks.
Breast wall: This part has powder scattering and melted material flowing down from the top of the arch. The operating temperature is 1500~1600℃. It is recommended to use F-AZS, high-quality silica bricks, and RA-H (liquid flow hole bricks).
Rear wall (feeding port side): This part has powder scattering and melted material flowing down from the top of the arch. The operating temperature is 1450~1600℃. It is recommended to use F-AZS and high-quality silica bricks.
Hook bricks and nozzle bricks: This part has powder scattering and melted material flowing down from the top of the arch. The operating temperature is 1500~1600℃. It is recommended to use F-AZS.
Pool wall: Contact with sodium silicate melt. Operating temperature 1400～1600℃; F-AZS (QX and WS) is recommended
Corner bricks at the feeding port: contact with sodium silicate molten liquid, temperature changes, large powder accumulation, severe mechanical scouring; operating temperature 1400～1600℃; F-AZS (WS, ZrO241% grade) and F-AZSC are recommended.
Bubble bricks, electrode bricks and kiln sills: contact with sodium silicate molten liquid, forced scouring of liquid flow; 1400～1600℃; F-AZS (WS, ZrO241% grade).
Flow hole cover: contact with sodium silicate molten liquid, gas-liquid phase upward drilling erosion; 1300～1450℃; F-AZS (WS, ZrO241% grade) and F-AZSC.
Sidewalls of flow hole channel: contact with sodium silicate molten liquid; F-AZS (WS).
Pool bottom paving layer: contact with sodium silicate melt, metal drilling erosion, gas-liquid phase drilling erosion; 1300～1500℃; F-AZS(WS).
Pool bottom sealing layer: metal drilling erosion; 1200～1400℃; electro-casting AZS ramming material + zircon or B-AZS.
02 Operation Room
Arch top and arch foot bricks: low temperature and less temperature change, no dust flying; 1250～1400℃; silica bricks, mullite/sillimanite bricks.
Breast wall: low temperature and less temperature change, no dust flying; 1250～1400℃; silica bricks, mullite/sillimanite bricks.
Pool wall: contact with sodium silicate melt; 1300～1400℃; F-AZS(oxidation method), RA-M.
Pool bottom paving layer: contact with sodium silicate melt, gas-liquid phase upward drilling erosion; 1300~1400℃; F-AZS (WS, oxidation method), RA-M.
03 Small furnace
The arch and side walls of the small furnace crater: flying powder, the flow of the top of the arch after melting, and the temperature change of high temperature; 1500~1600℃; F-AZS.
The small furnace inclined arch is inserted into the flat arch, bottom and side walls: the scattering of powder, the temperature change of high temperature; 1450~1550℃; F-AZS directly bonded magnesia brick (MrO97%), high-quality silica brick, B-AZS, re-sintered fused mullite brick.
04 Lattice body
Ceiling, upper wall:
(Air) Powder scattering, high temperature change, repeated oxygen reduction; 1300~1500℃; high-quality silica brick, direct bonded magnesia brick (MgO97%), re-sintered fused mullite brick.
(Gas) Powder scattering, high temperature change, repeated oxygen reduction; 1300~1500℃; high-quality silica brick, re-sintered fused mullite brick.
Middle wall:
(Air) Powder scattering, high temperature change, repeated oxygen reduction; 1300~1500℃; silica brick, fused re-bonded magnesia brick, low porosity clay brick (9%~12%).
(Gas) Powder scattering, high temperature change, repeated oxygen reduction; 1300~1500℃; low porosity clay brick (≤12%).
Lower wall: low temperature change; low porosity clay brick.
Top checker bricks:
(Air) High temperature temperature change, powder scattering, repeated oxidation and reduction; magnesia zirconium bricks, ER5312RX.
(Gas) High temperature temperature change, powder scattering, repeated oxidation and reduction; re-sintered fused AZS bricks.
Upper checker bricks:
(Air) High temperature temperature change, powder scattering, repeated oxidation and reduction; 1200~1400℃ direct bonded magnesia bricks (MgO97%) + fused re-bonded magnesia bricks (MgO95%), ER5312RX.
(Gas) High temperature temperature change, powder scattering, repeated oxidation and reduction; 1100~1200℃; three low (low creep, low porosity, low iron) bricks, re-sintered fused AZS bricks.
Middle checker brick:
(Air) Condensation of alkali vapor, solid-liquid change of sulfate, repeated oxidation-reduction; 1000~1200℃; fused rebonded magnesia brick (MgO92%), medium temperature magnesia-zirconium brick, ER1682RX.
(Gas) Condensation of alkali vapor, solid-liquid change of sulfate, repeated oxidation-reduction; 800~1000℃; ultra-low porosity clay brick (<12%), low porosity clay brick (<15%).
Lower checker brick:
(Air) Low temperature change; 600~1000℃ low porosity clay brick (<15%).
(Gas) Low temperature change; 400~800℃ low porosity clay brick (<15%).
Lattice support block: temperature load, dust fixation, temperature change; >1000℃; F-AZS, mullite/sillimanite bricks; <700℃ low porosity clay bricks (<15%).
Material Notes
Notes:
1. F-AZS means fused-cast zirconium corundum brick.
2. F-AZSC means fused-cast chromium zirconium corundum brick.
3. B-AZS means sintered zirconium mullite brick.
4. RA-M means fused-cast α·β-corundum brick, RA-H means fused-cast β-corundum brick.
5. QX means inclined casting, WS means no shrinkage cavity.
6. Fused rebonded magnesia brick (MgO92%) means that the amount of fused magnesia added in the batch is not less than 30%.
7. The temperature shown in the table refers to the temperature measured by thermocouple or optical pyrometer.
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