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Refractory mortar is a safe and easily available useful material. In this blog, you will know about its uses, tips to mix and types of the mortar available.

What is Refractory Mortar?

The refractory mortar is not an organic, non-metallic and absorbent in nature material. We can see the usefulness of this material by using this in Kilns, furnaces, other reactors, etc. The refractories are also in use for manufacturing casts and crucibles for casting glass and other metals. In addition, it is preferable in coating, patching, and bonding of alumina brick needs refractory mortar.

This material decomposes forced heat, chemical attack, and pressure on the object. This engineer’s oriented material is prepared with a mix of appropriate quantities of sand, aluminate, calcium, and clay.

Types of Refractory Mortar

According to permitted code under ASTM C 199, refractory mortar is of two types. such as

Hydraulic Setting Mortar

Hydraulic Setting Mortar
Fig.- Hydraulic Setting Mortar

This is considerably the best mortar because of its non-soluble water nature. It requires mixing of aggregate and binder for up to 6 hours minimally. The mixing process must be done at a temperature of 1499C.

Air Drying Mortar

refractory Mortar
Fig.- Air Drying Mortar

The air drying mortar takes more time to dry as its name suggests. That is why it is recommendable in hot and dry areas. the other name of this mixture is premixed mortar containing clay, liquid silicate and aggregates. In comparison to the former, it has inferior qualities.

How to Make the Mix Refractory Mortar?

The best services of this industry need the right installation of the refractory mortar. The number or amount of the mixture components must be desirable. Unless it’ll have less power or toughness and hold to the infrastructure. The mixing of the mixture components is not easy. As it is not simply adding water and stirring the parts. It needs the right precautions given below:

  • The mason needs to carefully add the right quantity and weight of the elements and water.
  • Don’t add water on to the water hose.
  • Mix the elements for an appropriate period to get rid of lumps in the mortar.
  • The best method to combine or stir the mortar is by hand or paddle.
  • The consistency of the mixture should be the best.

Important Tips to mix

To improve the practicality of the mortar and to get the best results. Some professionals follow some formulas. You will get the proper plan or the best idea with the following formulas:


The quantity relation shows the quantitative relation of Sand, metallic element Calcium Compound Cement and Fireclay.

The other formula uses specifically lime and Portland cement.

Important Tips to mix
Fig.- Important Tips to mix


This other quantity relation shows the best relation among the quantity of Sand, Fireclay, Portland cement and another acidic element i.e. Lime.

So, relying upon the need and usefulness of the material used in mortar. You will make simply the best functional refractory mortar.

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Uses of Refractory Mortar

As, this mortar is highly heat resistant. Thus, it is majorly in use in strong heat emitting the steel and some of the foundry industries. Many useful advantages and functionalities of refractory mortar are mentioned as:

  • Refractory mortars work to arrange precast shapes and place the refractory bricks.
  • It acts as a thermal barrier in between a wall of mortar carrier vessel and a hot medium of application.
  • Refractory Mortar is also applied as a precaution for the infrastructure from corrosion.
  • It also provides thermal insulation.
  • Along with this, a refractory mortar can reduce the erosion of vessel walls imposed through heavy stress or pressure. Therefore, it prevents any hot medium.

These are purposeful uses of the refractory mortar. Now, we should also consider about application uses of this material. Those are as follows:

  • It is mainly used to put lining furnaces, Kilns, reactors, etc.
  • It acts as a holder and transporter for hot mediums. For instance, metal and slag.

To clarify more, the application uses of refractory mortar are as below:

  • Fired heaters
  • Ammonia primary as well as secondary reformers.
  • To crack furnaces
  • Act as utility boilers and catalytic cracking units. And,
  • Air heater and sulfur furnaces.

General FAQs

What is the difference between Refractory mortar and refractory cement?

It is an unshaped refractory material mainly used for bricklaying. On the other hand, refractory cement acts as its binder. It is rarely in use alone in any project.

Can the fire cement expand?

Fire cement is available to ready to use that acts as heat resistant up to 1250oc. The cement is expandable only by heating it up on more than 300 degrees centigrade. Otherwise, the cool down cement is inflexible.

what should be the thickness of refractory cement?

The thickness of the refractory cement depends upon the function of the project. Moreover, the cold- face or shell temperature to hold the cement for the long. Though, the preferable thickness is between 40 mm to 200 mm.

What are the types of refractory Mortar?

The refractory mortar is mainly of two types as per ASTM C 199. Including Hydraulic Setting Mortar and Air drying or Premixed mortar. There was also the third type as job-site mixed mortar. Though, it is not in use these days.

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