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Application of high alumina refractory plastic in heating furnace
Dec 12, 2018

The application of heating furnaces is very extensive, such as steel smelting, petroleum, chemical, etc., no matter which industry is used, refractory materials are an essential and important component of heating furnaces. The traditional furnace lining adopts low cement castable, but the low cement castable has a relatively high loss. The current application has been basically replaced by high alumina refractory plastic.

1. Damage mechanism of furnace lining

There are many types of heating furnaces, and the most used ones are continuous heating furnaces, which have a complicated structure and are continuously produced. The furnace is mainly divided into a preheating zone, a heating zone and a soaking zone. The damage of the furnace lining mainly comes from the erosion of the furnace lining and the impact of temperature changes and air flow.

The traditional low-cement castable is used, and the aggregate has a large expansion property after high temperature, which easily causes cracks and peeling of the lining. Moreover, the low cement castables are poor in acid corrosion resistance.

2, high alumina refractory plastic choice

In the selection of refractory plastics for heating furnaces, high alumina refractory plastics are mainly selected. High-aluminum refractory plastics are mainly made of high-quality high-aluminum aggregates, alumina powders, chemical binders, etc. in a certain proportion. High-aluminum refractory plastics have high plasticity, and can be used in heating furnaces to compensate for the lack of performance of refractory castables and improve the life of the lining.

3. Construction and oven of high-aluminum refractory plastic

1) Construction

1 Preparation before construction: Quality inspection of refractory plastic and anchor bricks should be carried out before construction to ensure that all performance indicators of the materials meet the standards. The tools for construction and the surface of the construction body should be clean.

2 modules: The bottom template should be spaced 5-10 mm from the anchor bricks.

3 beats: The beating is performed with a hammer, and the direction must be perpendicular to the template to ensure at least one round trip. The layer must be shaved between the layers. If the construction is stopped in the middle of the construction, the already-operated beating layer must be shaved.

4 When installing the anchor brick, it must be ensured that it is tightly combined with the plastic;

5 demoulding: The general demoulding time is carried out within 4 hours after the completion of construction. At the same time, the kiln performs surface shaving, expansion joints and pores.

2) Oven

In order to obtain a lining with a long service life, in addition to the above material selection and construction must be done, the oven is also a key link. The main purpose of the oven is to discharge the crystallized hydrated free water in the refractory plastic. In the process of oven, it can not be rushed for success, the oven is too fast, the water vapor discharge in the construction body is blocked, and it is easy to cause cracks or peeling, which affects the use of the heating furnace in the later stage. Therefore, the oven must be ensured in accordance with the refractory plastic oven curve.

4, high aluminum refractory plastic life cycle

There are many cases of high-alumina refractory plastic construction heating furnaces. The period of use of cement castables is twice as long, the life of castable linings is 2~3 years, and the use of high-aluminum refractory plastics can be used for 7 years. the above. The surface of the lining has been kept flat and there is no obvious damage.

to sum up 

Refractory plastics are much higher in price than refractory castables, but their cost performance is much higher than that of refractory castables. Therefore, the replacement of refractory castables by refractory plastics as a furnace lining has become an ideal choice for many steel smelting and petrochemical enterprises.

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