Refractory Mortars

A refractory mortar is a fine-grained bonding material used to lay refractory bricks and fill the joints between them. It is supplied as a wet ready-to-use paste or a dry powder mixed with water on site. Beyond brick laying, mortars are also used for surface finishing of cast linings, expansion joint filling, and small hot-face patch repairs. The mortar must be chemistry-matched to the brick, fireclay mortar with fireclay bricks, high alumina mortar with HA-70/80, basic mortar with magnesia bricks.

Chemistry. Fireclay mortar is 30–42% Al₂O₃ with the rest silica and binder, rated to about 1400°C, used with fireclay bricks. High alumina mortar (HA-50 to HA-80) carries 50–82% Al₂O₃ to match the brick course it lays, rated up to 1750°C. Basic mortar is 85–92% MgO, used with magnesia and dolomite bricks in steel converters and cement kiln burning zones. Using the wrong chemistry creates a chemically incompatible joint that cracks, spalls or melts at temperature.

Air-setting mortars develop strength on drying at room temperature, convenient for repairs that cannot be heated. Heat-setting (ceramic-bonded) mortars are weak when laid but develop high refractoriness at 800–1000°C, used for the strongest hot-face joints. Hydraulic mortars contain calcium aluminate cement and set wet, like a fast-curing castable. We help match the setting type to your installation schedule and dry-out plan.

Generally 1–3 mm for dense fireclay and high alumina brick courses, 1–2 mm for basic and MgO-C brick courses (where thinner is always better for slag resistance), and 3–6 mm for insulating fire bricks and acid-proof tiles. Thicker joints lower the overall lining strength and become the first failure point. Apply mortar to BOTH the bed and the brick face (buttered joint) for full contact.

Yes. We stock furan resin mortar (best resistance to most strong acids except HF), phenolic resin mortar, and potassium silicate mortar for milder duty and high-temperature acid environments up to 1000°C. These are paired with Crown Ceramics acid-proof bricks and tiles to form the complete acid-resistant lining system, including grout and primer.

We are a strategic supply partner for Mahakoshal Refractories, covering their full mortar range from fireclay to HA-80, basic, and insulating grades. We also supply CUMI Super Refractories (authorised dealer) and Calderys mortars for matching their proprietary brick chemistries, plus Crown Ceramics acid-proof mortars (authorised dealer). Same-day dispatch from Delhi for standard grades.

Mortar 70 (Ace Calderys) and Tata 70M (TRL Krosaki) are competitor trade names for the same 70% alumina heat-setting mortar as CUMI's Cumiset 70, which we supply matched to your brick specification. See the full cross-reference table above for the rest of the Cumiset / Mortar / Tataset range.

Use a 70% or 80% Al₂O₃ mortar, CUMI's Cumiset 70 or 80, sold elsewhere as Mortar 70/80 (Calderys), Tata 70M/80M (TRL Krosaki) or Maxset (Mahakoshal), never a fireclay mortar, which becomes the weak point in the joint. We match mortar chemistry to your brick grade before dispatch.