News

SINO-FOUNDRY—professional refractory manufacturer

/
/
Selection and Analysis of Refractory Materials for Thermal Insulation Furnace

Selection and Analysis of Refractory Materials for Thermal Insulation Furnace

(Summary description)In recent years, there have been more and more thermal insulation cotton production enterprises in China.

Selection and Analysis of Refractory Materials for Thermal Insulation Furnace

(Summary description)In recent years, there have been more and more thermal insulation cotton production enterprises in China.

Information

In recent years, there have been more and more thermal insulation cotton production enterprises in China. However, due to the special composition and production process of thermal insulation cotton products, the refractory materials of the melting furnace for the production of thermal insulation cotton have become more and more important. At present, the lifespan of thermal insulation cotton melting furnaces in my country is generally about 3 years, and there are not many kilns with a life of more than 5 years. The main reason is the selection of refractory materials for various parts of the melting furnace.

The design principle of the refractory material of the thermal insulation cotton melting furnace is: within a kiln period, strive to make the erosion of the refractory materials of all parts of the melting furnace basically synchronized. This is the most economical and reasonable.

The analysis of the refractory material configuration of each part is as follows:

(1) Because the melting temperature of the pool wall of the melting part is low, generally below 1400℃, and the viscosity of the glass liquid is large, the reaction diffusion rate is small, so the erosion of the pool wall is small. Generally, 33 oxidation method fused zirconia corundum bricks are used. That's it. For the horizontal flame furnace, in order to achieve a longer kiln age, chromium-zirconium corundum bricks with a chromium content of 30% need to be used on the wall of the melting part. No matter what kind of refractory material is used, no heat preservation is done near the liquid level line of the pool wall, and air cooling is used to extend the service life of the pool wall.

(2) The melting part breast wall The melting part breast wall is in the flame space of the furnace. Due to the high temperature and hot air flow, a large amount of alkali and boron volatiles adhere to the surface and gaps of the breast wall bricks, and chemically react with the breast wall bricks to cause corrosion. Therefore, breast wall bricks generally choose neutral or alkaline refractory materials with stable high temperature chemical properties, resistance to alkali and boron. For breast walls with low kiln age, 33 fused zirconium corundum bricks are the best choice, but for breast walls with long kiln age, sintered zircon bricks or chromium zirconium corundum bricks with 30% chromium content are better.

(3) Because of the large heat dissipation area at the bottom of the melting part, the paving bricks at the bottom of the melting part should not only strengthen the heat preservation, but also consider the increased erosion caused by the increase in the temperature of the bottom of the bath due to heat preservation. Fused zirconium corundum brick pavement is the first choice for the bottom of the thermal insulation wool furnace. For most thermal insulation wool furnaces, the stability of this material is fully matched with the life of the furnace. When the molten glass depth of the melting furnace is less than 500mm and bubbling is used, the high temperature of the molten glass at the bottom of the pool and the strong convection of the molten glass produced by the bubbling greatly aggravate the mechanical erosion and erosion of the molten glass on the refractory materials at the bottom of the pool. The use of traditional fused zirconia corundum brick paving layer is difficult to meet the long kiln age (over 5 years), so it is more suitable to choose chromium zirconium corundum brick with 15% chromium.

(4) The sluice of the melting part For the horseshoe flame insulation cotton kiln, most of the sluice top adopts silica brick. Although alkaline bricks are suitable for alkaline glass solution, silica bricks are cheap and have poor corrosion resistance to alkaline vapors. Due to the high content of boron and alkali in the thermal insulation cotton, when the glass glaze on the surface of the brick is lost, under the action of boron and alkali vapor, the silicon brick is easily eroded, thereby affecting the life of the furnace. At present, the silicon brick roof of the domestic horseshoe flame insulation cotton melting kiln generally produces rat holes after 9 months to 1 year, which requires frequent maintenance and repair, which can barely last for 3 years. Repairing the dome roof is not only a heavy hot repair work, but also has an impact on production. If you want to obtain a kiln age of more than 5 years, the roof material of the insulation cotton melting furnace is not suitable for silica bricks. Instead, chromium-zirconium corundum bricks with 30% chromium or special sintered mullite bricks should be used.

(5) Liuyedong Liuyedong is the most easily corroded part of the thermal insulation cotton melting furnace and cannot be repaired in a hot state. Therefore, the service life of the refractory material of the Liuyedong directly determines the life of the furnace. At present, most of the flow holes of thermal insulation cotton melting kilns use no production experience shrinkage fused zirconia corundum bricks. Because the temperature of the molten glass in the thermal insulation cotton melting furnace is relatively low, generally below 1250°C, the erosion of refractory materials in the liquid cave is mainly mechanical erosion. For small-tonnage thermal insulation cotton kilns, non-shrinkage fused zirconia corundum bricks can fully meet the requirements of kiln age, but for large-tonnage and long kiln thermal insulation cotton kilns, flow cave bricks use 50% chromium chromium Zirconium corundum bricks will be more reasonable.

(6) The thermal insulation cotton of checker bricks contains high alkali and low boron, which can erode magnesia bricks severely. In addition, alkali vapor and boron vapor are easy to crystallize in the middle temperature region (810~940℃), and the crystallized product has a high viscosity and adheres to the uneven surface of the checker brick after corrosion, thereby causing the checker brick to block. At present, the checker bricks of glass wool furnace generally use alkaline bricks, the upper layer is 97 magnesia brick or 98 magnesia brick, the middle layer is 95 magnesia brick or 96 magnesia brick, the lower layer is magnesia chrome brick and low-porosity clay brick. The cost of the checker bricks configured in this way is relatively low, but because the alkali vapor and boron vapor crystallize and adhere to the checker bricks, the checker bricks need to be replaced after one and a half years of use. For checker bricks with long kiln age, cross-shaped fused zirconia corundum bricks are the first choice.

(7) Passage For the upper structure of the flame kiln passage, 33 fused zirconia corundum bricks or sintered zircon bricks are generally used. For the upper structure of the electric furnace passage, sintered mullite bricks can be used. The passage in contact with the molten glass can be 33 fused zirconia corundum bricks or chromium zirconium corundum bricks containing 30% chromium.

Reasonable matching of refractory materials for thermal insulation wool furnace is the key to high efficiency. Of course, the selection of refractory materials needs to comprehensively consider factors such as kiln age, investment, refractory material status and production cycle to make the operation of the furnace the most effective and economical.

Scan the QR code to read on your phone

Related News

ewm
WeChat public account
ewm
View mobile website

Contact Us

Address : No. 99, Yiqing Road, Gaozi Street, EconomicDevelopment Zone, Dantu District, Zhenjiang City

Fax : +86-511-85683066
E-mail :
sales@sfr168.com   
Website :
http://www.sfr168.com
Copyright © 2021 Sino-Foundry Refractory(Jiangsu) Co.,Ltd. All Rights Reserved. 苏ICP备19058941号-1 Powered by:www.300.cn Changzhou
返回顶部
搜索
Search