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Formulation Of Silicon Brick Hot Blast Stove Oven Curve
Jan 08, 2019

In the masonry of the top-fired hot blast stove, the hot blast stove built with silica brick is called silica brick hot blast stove here. After the completion of the brick brick hot blast stove, the oven is the longevity hot blast stove. The key link, therefore, the formulation of its oven curve is also very important.


The use of silicon brick masonry top-fired hot blast stoves is very extensive in China. As we all know, the main chemical composition of silica brick is silica, which exists in different crystal forms at different temperatures. The main mineral composition of the fired silica brick is: γ-quartz, β-cristobalite and a small amount of residual β-quartz . During the process of the oven, there will be a large volume change of each mineral phase change. Therefore, the formulation of the silica brick hot air oven oven curve is complicated. The development of scientific and strict oven curves and reasonable operating guidelines will greatly improve the service life of hot blast stoves.


According to the above analysis of the chemical transformation of silica bricks, the silicon brick hot air oven oven process is planned for 45 days. The oven fuel is made up of fully mixed gas and divided into different heating stages.


1) Maintaining for less than 300 °C for 21 days, the purpose is to eliminate the mechanical adhesion of water in the masonry, and also to the conversion of γ-scale quartz to β-tridymite, and then to α-scale quartz, the transformation of phosphorus quartz The temperature is between 110 and 160 °C, the volume change during conversion is 0.20%~0.28%, the transformation temperature of cristobalite is 170~270°C, and the volume change during transformation is about 3.0%.


2) Keep it at 300~600 °C for 16~17 days, and continue to remove the moisture in the deep part of the masonry. In addition, near this temperature, there may be a conversion of β-cristobalite to α-cristobalite in the silica brick, accompanied by a large volume expansion, and a slow temperature rise for a long time can reduce the temperature difference in the thickness direction of the masonry. To avoid damage to the masonry.


8) Maintaining at 600~800 °C for 6~7 days, adapting to the conversion of β-quartz to α-quartz which may remain in the brick. The transformation temperature of quartz variant is 570 °C, the volume change during conversion is 0.82%, and the distance can be made. The crystal water in the brick with a high temperature surface is precipitated, and the SiO2 can be transformed into a crystal form.


4) Keep it at 800~1000 °C for 1~2 days, so that the hot blast stove can be further baked as a whole, and the temperature will continue to rise in equilibrium to reach the level required by the blast furnace.


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