Requirements of Refractory Materials During Blast Furnace Lining Repair
Generally speaking, there are several blast furnace lining maintenance methods including grouting for lining making, cold spray technology, digging hole on furnace shell technology and remote control spray technology.
Grouting for lining technology can be widely applied to hot point short-term repair of blast furnace stack and furnace bosh. It is a means of prolonging furnace life, but it must be repaired repeatedly to keep the lining at a certain thickness. Different furnace parts use different refractory materials, the mud consistency is a key element for the success of grouting for lining technology.
Using cold spray technology not only can make blast furnace cleaned thoroughly, but also can firmly bond old and new refractory materials and then lead to a good furnace lining form and make the first run of the blast furnace successful. While, repairing blast furnace in cold spray technology needs too much time, it is a limited element for its widely using.
Digging hole on furnace shell and gunning damaged parts with long gun technology is usually applied to damaged furnace lining and shell technology, it uses a long gun to spray and repair the inside damaged parts from outside. This method has the advantages of speed spraying and short wind time, but it is only suitable for partial damage.
Remote control gunning technology is an advanced technology which is now being developed and used in China and many other countries in recent years. Its gunning time is short and its gunning range is large, but it needs complex technology.
In a word, grouting for lining technology requires appropriate refractory mud consistency; the other three repair technologies require good refractory adhesion under high temperature and normal temperature so that to make spraying coating in a certain thickness continuously, and the coating is tightly bonded into a no pull-off and dense formation which can be dried and warmed fast.