The most important thing for flue lining is to consider the problem of acid gas erosion and erosion. Acid gas must use acid-resistant castable or acid brick to do the lining, but the flue has vertical and horizontal, vertical to consider the weight of the problem, if too heavy or the chimney is too high, there will be great difficulty in lifting the combination.

When the lining material is selected, the weight must be considered as well as the erosion problem. If the acid brick is used, the problem of weak air tightness will occur because of the ash joint. If light acid resistant castable is selected, the scouring and erosion ability is not strong, nor can it meet the use of flue liner, and the flue liner temperature is not high, basically do not need to be insulated to deal with.

Therefore, it is necessary to consider the use of semi-heavy acid-resistant castable, because the semi-heavy body is dense at about 1.5, which can resist erosion and erosion, and can play a part of the thermal insulation role. Another reason is that the weight problem has also been alleviated. At present, the semi-heavy acid-resistant castable is an ideal material for flue lining in terms of market conditions and chimney properties. Ideal for use in large diameter flues.