Refractory Mortar

Refractory mortar and refractory castables are shapeless refractory materials. And commonly used materials for thermal linings、refractory industry. Refractory mortar also called refractory mud or joint material, is composed of refractory powder and admixtures. It is mainly used as a joint material for refractory masonry products. The particle size of refractory mud can be changed according to the use requirements. Its ultimate particle size is generally less than 1mm, and some are less than 0.5mm or finer. When using refractory mortar, the same material as the refractory products for masonry should be used. Almost any refractory material can be made into powder for making refractory clay.

Refractory castables are composed of various refractory aggregate powders as the main raw material, refractory cement as a combination, and adding anti-shrinkage agent, explosion-proof fiber, coagulant and other admixture materials. It has high fluidity and is also used for pouring construction. Become a castable. Suitable for unshaped refractory materials formed by casting. Compared with other unshaped refractory materials, it has higher binder and moisture content, so it has better fluidity.

Refractory mortar can be divided into clay, high alumina, siliceous and magnesia refractory mud according to the material. When laying bricks, refractory mud of the same material is used according to the material of the refractory bricks. If clay bricks are built using clay refractory mud, the refractory mud will be high alumina fire mud is used for building high alumina bricks, magnesia fire mud is used for building magnesia bricks, carbon fire mud is used for building carbon bricks, etc. There are many types of refractory castables. Commonly used ones include high-aluminum castables, corundum castables, low-cement castables, mullite castables, wear-resistant castables, anti-seepage materials, self-flowing castables, plastics, etc.

The characteristics of refractory mortar are: Has good plasticity and is easy to construct high bonding strength and strong corrosion resistance. Refractory castable materials are made from a wide range of materials and are easy to be comprehensively utilized. Convenient construction, low labor intensity, high masonry efficiency, and mechanized furnace construction can be realized;the masonry structure has fewer joints and strong integrity. There are no gaps between castables, and it has high structural strength and resistance to slag penetration.

Refractory mortar is used as joint material for refractory masonry. It is a material that is matched with refractory bricks at any time. It can not only be used as a joint material, but can also be used as a protective coating for the lining by applying or spraying. Refractory castables are joint materials used for building refractory bricks. They are generally used as integral lining products for kilns and as integral lining materials for pouring construction. During on-site construction, the castables and binders need to be pre-mixed, then appropriate water is added, stirred evenly and then poured into the installed lining mold. Vibrated with a vibrating rod to form, after curing, demoulding and baking. It can be put into use. It can be cast and formed, self-flowing, ramming construction, spraying construction, customized castable prefabricated block masonry construction, etc. They have a wide range of applications, and the materials and binders used can be selected according to the conditions of use. It can be directly poured into a lining and used, or it can be made into prefabricated blocks by pouring or shaking.

This type of refractory mortar is a blend of aggregates and binders that are not only high temperature resistant but are acid resistant as well. This product is now the best all-around refractory mortar for fireplace and chimney construction. It is also the preferred choice for installation of the high temperature resistant component parts for masonry bread ovens. It has the workability of a regular mortar mix, may have mortar color added to it, and is preferred if the joint thickness exceeds 1/8”. Non-water soluble refractory mortar is the only refractory mortar that should be used in outdoor applications. Premixed refractory mortars may wash out even after drying. Due to the previously mentioned characteristics, non-water soluble product is the preferred choice for clay flue installations that may vent gas or oil appliances or in any other instance where moisture may be present within the clay flue. This is our overall refractory mortar of choice. It is used four to one vs. other types of refractory mortar in residential construction.

Premixed refractory mortar is a blend of clays, aggregates, and has a liquid silicate as a binder. Some masons prefer it simply because it is premixed, nothing needs to be added, and with a simple quick stir it is ready to use. Since the firebrick can be laid in place very rapidly installation is a little quicker. Ten seconds after setting the firebrick it takes some effort to dislodge them and the fast drying of the mortar does not compromise its strength like with regular mortar. Premixed mortar can be a little messy to use but remember it is water soluble, so it cleans up easily with water. You should butter a thin layer of refractory mortar on the firebrick that you are going to lay. Use a small margin trowel because it fits in the bucket better than a pointed trowel. After applying a small amount on the firebrick, tap the firebrick in place so that the joint thickness is approximately 1/16″ and the excess mortar that oozes out from between the firebrick is removed with the margin trowel. Take your time and avoid the mess. The best thing is to lay a few firebricks and then clean up the face of the firebrick with a sponge and clean water. The longer you wait to clean up the face of the firebrick, the harder it is to get all the particles saturated and removed. In hot and dry climates we prefer the premixed refractory mortar because it does not seem to dry out as quickly as do other mortar types.

Refractory mortar is a specialized type of mortar used for bonding and sealing high-temperature materials in various applications, such as furnaces, kilns, and fireplaces. It is designed to withstand extreme heat and provide excellent adhesion in challenging environments. While commercially prepared refractory mortars are readily available, making your own can be a cost-effective option. 

Fire clay is the primary ingredient in refractory mortar. It can withstand high temperatures and provide good adhesion. Approximately 50–60% of the mixture will consist of fire clay. Silica sand helps improve the workability and strength of the mortar. It makes up around 30–40% of the mixture. Lime acts as a binder and plasticizer in the mortar. It contributes to the mortar’ s workability and helps it set. Use about 10–20% of the mixture for lime. Water is necessary to achieve the desired consistency of the refractory mortar. Gather the necessary refractory mortar recipe and ensure a clean and well-ventilated workspace. Measure the fire clay, silica sand, and lime according to the desired proportions. For example, a common ratio is 50% fire clay, 30% silica sand, and 20% lime. Combine the dry ingredients (fire clay, silica sand, and lime) in a large container or wheelbarrow. Mix them thoroughly using a shovel or trowel to ensure a homogenous mixture. Gradually add water to the dry mixture while continuously mixing. Aim for a consistency similar to regular mortar, where the mixture holds its shape when squeezed but is not overly wet. Add water gradually to avoid making the mixture too runny. Continue mixing the refractory mortar until it reaches a smooth and uniform texture. Ensure that all dry ingredients are evenly wetted. Allow the refractory mortar to rest for approximately 10–15 minutes to ensure proper hydration and to achieve optimal workability. After resting, remix the mortar to ensure consistency and break up any lumps that may have formed.

Your homemade refractory mortar is now ready to use. Apply it to the desired surfaces using a trowel or other suitable tools. We also produce soft fire bricks. It is crucial to wear appropriate protective gear, such as gloves and a dust mask when handling the dry ingredients to prevent skin irritation and inhalation of dust particles. The proportions of the ingredients can be adjusted based on specific requirements and desired characteristics of the refractory mortar. Experimentation may be necessary to find the ideal mixture for your application. Refractory mortar should be used within a reasonable time frame, as it can start to harden quickly once water is added. Avoid mixing more mortar than you can use within a short period.