Unshaped Refractory Description

Unshaped refractory is the kind of dry or wet ( semi-wet) refractory material composed of refractory aggregate( grains and fines), binding agent and additives. Unshaped refractory can directly be used to construct or patch the linings of industrial furnaces and kilns. Differing from shaped refractory products, unshaped refractory can construct seamless integral inner lining, so is called seamless refractory material or monolithic refractory in Europe and Americas. In East Europe and Russia, unshaped refractory is also called refractory concrete,  because the preparation craft and application method of unshaped refractory is similar to ordinary construction concrete.

Compared with burned refractory products, unshaped refractory material has following characteristics

Simple production craft, short production cycle and manufacturing efficiency.

Good adaptability, can be made into any shape to meet special construction situations of  industrial furnaces.

Excellent integrity, air tightness and thermal resistance, can reduce heat loss of industrial furnaces and save energy.

Convenient for mechanical working, is time and labor saving.

Suitable for the patching of damaged industrial furnace inner lining, can prolong lining service life and decrease refractory material consumption.

Thus, unshaped refractory is gradually replacing some burned refractory products and widely used in industrial furnaces and kilns, for examples, in metallurgy, unshaped refractory accounts for 45%~70% of the refractory material consumption.

The Classification Of Unshaped Refractory Material

By working craft, unshaped refractory material can be divided into 8 groups

1. Casting refractory material (castable): Dry type refractory mixture, should add liquid (water or liquid binder) when it is took into application. Casting refractory will have certain structural strength after cementation and hardening. Castable can further be classified into vibration castable, self flow castable and pump grouting castable.
2. Ramming refractory material( ramming mass): Semi wet or wet refractory mixture with low or no plasticity, can be applied by ramming method. Ramming mass will has structural strength when heated and hardened.
3. Plastic refractory: has some degree of plasticity, can be applied by ramming method or gunning method. Plastic refractory need to add plasticizer, such as plastic clay, organic agent and so on.
4. Gunning refractory mix: Can be applied by gunning method through high speed current carrier produced by gunning machine. By gunning craft, gunning methods can be divided into cold material gunning method and molten gunning method.
5. Coating refractory material: Pasty or slurry shape refractory mixture, including refractory mortar and coating mix. Can be applied by manual coating, mechanical coating or grouting method. Coating mix are usually used as joint material or joint grouting material for refractory bricks masonry, and can also be used as working lining and protection lining of refractory lining.
6.   Squeezing refractory material (injecting refractory material), a kind of refractory mixture applied by squeezing machine or pressure injection machine. Pressure injection mix can be divided into rigid injection mix and soft pressure injection mix. Rigid squeezing mix is plastic refractory, such as blast furnace stemming, blast furnace hot squeezing patch material and so on. Soft pressure injection mix is plastic mortar shape material, is mainly used as jointing material between refractory masonries or between refractory masonry and furnace shell.
7. Sling refractory: Refractory mix applied by manual or machine sling method, includes magnesia carbon hot patching material for large area amending of converter furnace lining and hot patching material for electric furnace bottom.

Dry vibration ramming refractory, also called stuffing material. It is dry refractory mixture, can directly stuff the gap between the mould and lining shell, for example, induction furnace inner lining, dry type tundish working lining, or the flowing nozzle constructed by refractory lining.