There are four key reasons for the deformation of ventilation ducts:

1.在自然養護標準下，鎂混凝土體積為連續膨脹過程，線膨脹率為0.1-0.2%，體積含水率為1%左右。

Under natural curing standards, the volume of magnesium concrete undergoes a continuous expansion process, with a linear expansion rate of 0.1-0.2% and a volume moisture content of about 1%.

2.燃燒過程中很難避開磁鐵礦，安裝在3C認證防火閥中的粗晶MgO水化過程緩慢。已產生抗壓強度的粉煤灰水泥中的MgO再次遇水并水化時，轉化為Mg(OH)2，體積增加120%。

2. It is difficult to avoid magnetite during the combustion process, and the hydration process of coarse-grained MgO installed in 3C certified fire dampers is slow. When MgO in fly ash cement that has developed compressive strength encounters water again and hydrates, it is converted into Mg (OH) 2, resulting in a volume increase of 120%.

3.水合后輕燒氧化鎂中分散CaO的體積增加90%，而鹵素片中存在SO42-。當Ca(OH)2轉化為成熟石膏時，固態體積會增加2倍以上，導致產物變形，這也是限制輕燒氧化鎂中分散CaO和鹵素片中SO42-含量的原因。

3. After hydration, the volume of dispersed CaO in lightly burned magnesium oxide increases by 90%, while SO42- is present in halogen flakes. When Ca (OH) 2 is converted into mature gypsum, the solid volume will increase by more than twice, leading to product deformation, which is also the reason for limiting the content of dispersed CaO and SO42- in halogen flakes in light burned magnesium oxide.

通風管道

Ventilation ducts

4.MgO-Mg-C12-H2O體系軟件的水化過程是一個明顯的化學反應過程，制造的管道體積較大。如果工作溫度高，反映的是升溫過程，板材本身過高，反映不夠，導致晶體地應力和熱變形地應力大，使產品體積膨脹。

The hydration process of MgO-Mg-C12-H2O system software is an obvious chemical reaction process, and the manufactured pipeline volume is relatively large. If the working temperature is high, it reflects the heating process. If the plate itself is too high, it will not reflect enough, resulting in high crystal stress and thermal deformation stress, causing product volume expansion.