Refractory is the main component of glass furnace, which has a decisive impact on glass quality, energy consumption and product cost. The future of glass melting technology depends to some extent on the progress of refractory production technology and product quality.
1. AZS brick, high zirconium brick
For AZS electric melting bricks, the production process is mainly to improve their corrosion resistance and wear resistance. In addition to adopting the melt oxidation method, the carbon content of the product is reduced to 0.005%, and the glass phase precipitation temperature is increased to 1450 ℃. The casting and annealing processes have also been improved, and it is now possible to produce fused AZS with little or no shrinkage. High ZrO2 zirconia bricks with ZrO2 content ≥ 90 have good thermal shock resistance, such as ZrO295 and SiO21.4. High ZrO295 zirconia bricks have a stabilizer of 3.7, an apparent density of 4.7 g/cm3, a porosity of 18.4, and a room temperature thermal shock resistance of 1400 ° C (interval of 15 minutes), which can reach 15-20 times. Fused cast zirconia bricks produced in Japan, with a zirconia content of 90, are called ZFC bricks. Their corrosion resistance is better than that of AZS bricks with a ZrO2 content of 40. At 1500~1600 ℃, after 16 hours, there is no glass phase precipitation, and the glass pollution is very small. After 40 times of thermal shock resistance at 800~1250 ℃, there is no crack.
2. Chrome brick and chrome brick
The compact chrome oxide bricks formed by isostatic pressing can be used for the side walls, necks or other seriously eroded parts of E glass and C glass tanks, and the service life can reach 6 to 7 years. In recent years, chromium containing products have made new progress. For example, Cr2O3 is added into AZS bricks to form Al2O3-ZrO2-SiO2-Cr2O3 refractory. At high temperatures, Cr2O3 forms solid melt with Al2O3 on the one hand, and Cr2O3 is a high melting point substance. As Cr2O3 enters the glass phase of the brick, the viscosity of the glass phase is increased, which increases the exudation temperature of the glass phase, and greatly improves the resistance to glass corrosion of glass products. An American company has produced a re bonded fused cast AZS/Cr2O3 refractory. Its chemical composition and physical properties are very superior. Compared with the original Al2O3/Cr2O3 material, the annual furnace power consumption is reduced by 4, the output is increased by 15, and the cost is reduced by 3.75. The glass quality is not affected. This kind of brick can be formed by machine pressing, manual ramming or isostatic pressing, and then sintered at high temperature.
3. Alkaline brick
Germany has been widely used in regenerator walls and swans through direct combination of 1800 ℃ sintered high-purity bricks and alkaline bricks. It has introduced a new material, named Rubinaiez, with chemical composition of MgO75, ZrO213.5 and SiO29.5. It is the combination of zircon and magnesia bricks. In the early stage of sintering, the structure of zirconium silicate bricks reacts with magnesium oxide. A layer of magnesium is formed around the square magnesite particles. With olivine and zirconia as the protective layer, this structure greatly improves the alkali resistance and sulfate resistance of the brick, and the regenerator in the middle of the grid brick has a good effect.
4. Olivine magnesia brick
Olivine binding phase has a particularly strong anti scouring property. The anti scouring property of magnesia brick can be improved by increasing the content of olivine magnesium in the binding phase of magnesia brick. Therefore, the addition of 20 kinds of forsterite fines in magnesia bricks can protect the formation of magnesia particles and reduce the erosion of forsterite bonding matrix. The cost of brick is relatively low, and it is widely used in the middle of the grid of the regenerator of glass furnace abroad.
5. Barite olivine brick
Considering that olivine has good corrosion resistance and insufficient thermal shock resistance, the thermal shock resistance of brick can be significantly improved by introducing barite in the bonding stage. Barite feldspar is formed during calcination and only exists in the bonding matrix stage. When the content of barite feldspar is 15 and the working temperature is about 1250 ℃, the performance of silica is the best. The research shows that barite feldspar is resistant to alkali and sulfate attack.
6. Unshaped refractory
The application of unshaped refractories in glass kilns is also a development trend. In the UK, refractory concrete precast blocks are used to build the heat storage chamber, checkered brick bottom arch, flue, small furnace support plate, burner, etc., which greatly reduces the joints of the furnace structure, improves the furnace building speed and shortens the cold repair time. The ERSOL in France is an unshaped refractory series made of ER1681 fused particles as the main component. It is used at the bottom of the tank together with the fused bricks, which has excellent resistance to glass corrosion, And the tendency of bubbles and stone formation is weak. The bottom of some glass kilns in Japan has been made of amorphous materials. The theoretical research of refractories used in glass kilns abroad focuses on how to further improve the resistance to glass corrosion and mechanical properties, in order to further extend the life of the furnace.
