Tenmat ltd

- Millboard


TENMAT FIREFLY Millboards are world's finest range of top quality non asbestos and non ceramic fibre millboard sheets for high temperature applications in all heat using industries.

Wet laid, clay bonded inorganic mineral fibre boards available in typically 1m x 1m square sheet format in thicknesses from 1.5mm to 12mm. All ranges possess high temperature capability, in excess of 1,000°C, and low thermal conductivity (K value), less than 0.1 W / mK, making them a first choice for thermal insulation applications.

At a density of typically 1,000 kg/m3 they are rigid, strong, and can be used in sheet form or cut to produce gaskets and seals.

They are all exonerated products in accordance with the European Directive 97/69 EC on Classification, Packaging, and Labeling of Dangerous Substances.

Various grades with unique properties are available for specific applications:

  • Roll coverings for lehr rolls in the float and flat glass processing (FF800)
  • Heathshields in molten metal casting (FF700)
  • Mould seals in spin casting of metal tubes and valves (FF900)
  • General gasketing in domestic appliances (FF700)
  • Sacrificial linings in primary aluminium melting pots (FF700)
  • Refractory back-up on furnaces (FF650)
  • High temperature gaskets and seals (FF650)
  • Heat shields (FF650)
  • Combustion chamber linings (FF650)


Aluminium Industry

Aluminium primary production and secondary processing plants benefit from the use of TENMAT's extensive range of products wherever heat must be contained, electrical energy controlled or wear resisted. TENMAT products offer cost effective solutions to improve energy utilisation, reduce weight and operating costs and increase life cycle operation.

  • SINDANYO L23 is used in the potroom in strip form between pot covers and cathode frames and in pad or plate forms between the anode support, the control gear and the super structure.
  • SINDANYO H91 is an ideal material for crust breaker discs, busbar and primary frame insulation and door frames.
  • ARCLEX provides the necessary electrical insulation of the cathode frame on its concrete base and to insulate busbars from the steel retaining and cathode frames.
  • FIREFLY FF700 MILLBOARD is a popular choice for many sealing requirements including syphon tube gaskets in molten metal transfer equipment.
  • FIREFLY FF700 MILLBOARD provides the insulating layer between the crucible and its hot face refractory lining, reducing heat losses thereby maintaining melt temperature longer. It is also used underneath the pots. FF700 possesses the necessary strength to be used as a permanent former when casting concrete.
  • Inside the pot FIREFLY FF700 MILLBOARD shields the anodes in order to exclude alumina whilst gas heating takes place during start up. Once operating temperature is reached the millboard becomes a sacrificial component in the pot.
  • RF1000 grade products are used as the insulation in crucibles, transport ladles and launder systems ensuring cost effective maintenance of liquid metal temperature for long periods of time.
  • CS1150 pouring nozzles have replaced conventional calcium silicate and cast iron tubes for flow control of liquid aluminium.
  • NITRASIL greatly extends the working life of graphite shafts used in rotary degassing equipment.
  • NITRASIL is hard and wear resistant. Its use as seats and pistons in valving operations ensures trouble free performance.
  • REFRAVER is used to resist attacks by fluorine in electrical and thermal environments.

These are just a flavour of the many applications for TENMAT products in the aluminium processing industries.


Furnace & Foundry

FIREFLY MILLBOARD FF900 has been used for decades at high temperature in contact with molten metals, and steel alloys in particular. Seals produced from this material have found widespread use as end plate protection in centrifugal or spin casting machines.

The process of centrifugal casting is one where molten metal is poured directly into a rotating mould which continues to rotate at high speed until the metal has solidified. The process confers particular desirable properties on the cast component e.g. absence of porosity, which cannot be achieved by static casting processes. The liquid metal, at a temperature as high as 1600 °C, is thrown against the inner wall of the rotating mould by the centrifugal forces generated by the rotation.

FIREFLY MILLBOARD FF900 was developed in response to a particular problem experienced by moulders, which was that after casting it was difficult to remove the cast component because it had stuck to the end plates. Previously, the mould and end plates were sprayed with silica and clay but this had not proved to be totally effective and a potential health hazard.

The solution to the problem was found by using a FIREFLY FF900 ring or disc, located between the end plate and the mould / component to be spun cast. The seal has been proven to be an effective release barrier, thereby alleviating the problem, and almost entirely eliminating wear of the endplates.

FIREFLY FF900 is able to withstand the very high temperature, typically in excess of 1560 °C, in the case of stainless steels, found in this application for several minutes whilst the required thickness of the component is achieved.


Glass Industry

FIREFLY MILLBOARD FF800 GLASS ROLL COVERING was developed over 25 years ago specifically to replace asbestos roll cladding materials in the flat glass industries.

Millboard can be used in sheet form in a wide range of applications in the glass industry, including heat shields, flue gas gaskets, and insulation pads for conveying newly formed glass components. However, it is in the form of rings for the assembly of sheet glass conveying rolls that FF800 demonstrates its unique high temperature strength, non marking and long life properties. The FF800 rings of typically 8 mm thickness are compressed onto a mandrel and machined.

FIREFLY MILLBOARD FF800 covered rolls are used in the float, flat and vertical drawn glass processes.


The float glass process was invented and developed in response to the need to make large sheets of high quality, distortion free glass more economically.

In this process, a continuous ribbon of molten glass, over 2 metres wide, moves out of the furnace and floats on the surface of molten tin. The ribbon of glass is held at a temperature for a period of time sufficient for all irregularities to be removed and the surface of the glass to become flat and parallel.

The glass is then cooled in a controlled manner until the surface is hard enough to be taken out of the bath on rolls without marking the bottom surface of the ribbon. The glass is then annealed in a lehr where the glass is transported over more than 200 rolls, gradually cooled to room temperature and cut to size. FIREFLY FF800 covering is used to produce these rolls.

The silk-like texture of the machined roll provides a surface which is kind to glass thereby eliminating scratching or scuffing of the hot glass. FIREFLY FF800 Glass Roll Covering contains high temperature binders that achieve optimum strength above 400 °C (750 °F). The rolls are operated continuously for many years because of their self cleaning properties. Unlike stainless steel or fused silica rolls, neither glass nor tin compounds adhere readily to the roll surface. Therefore, expensive cleaning operations, which can sometimes mean complete shut-down of the plant, can be avoided.


As for float glass, FIREFLY FF800 covered rolls are used to carry the glass from the furnace and through the lehr.


Although of a much smaller diameter and length, FIREFLY FF800 covered rolls are used to convey the ribbon of glass up the tower until it is cool enough to be cut and packed.

FIREFLY MILLBOARD FF800 covered rolls are eminently more versatile then stainless steel and fused silica types. They can be fabricated simply and are therefore, less costly. In the case of vertical glass drawing machines the covered rolls can be machined to include grooves/scallops to aid broken glass removal. Their inherent superior thermal properties and compressibility, compared to steel, confer improved operational control performance.

Glass manufacturers currently using FIREFLY FF800 Glass Roll Coverings include:

  • NSG / Pilkington Group
  • Saint Gobain
  • Asahi Glass Group
  • PPG
  • Taiwan Glass
  • plus many roll builders, float glass lehr manufacturers and vertical glass processing machine builders worldwide.


Molten Metal Processing

Molten metal processing plants worldwide benefit from the use of TENMAT's extensive range of high temperature materials.

TENMAT manufactures a wide variety of materials for thermal insulation, electrical insulation, gasketing and molten metal handling. Typical applications for TENMAT high temperature materials include pouring nozzles, tap out cones, molten metal transfer pump components, crust breakers, gaskets and many others.

SINDANYO, TENMAT's high temperature cement boards are the ideal materials for crust breaker discs, busbar and primary frame insulation and door frames.

FIREFLY Millboard is a popular choice for many sealing requirements including syphon tube gaskets in molten metal transfer equipment, centrifugal casting, ladle gaskets and plate rings.

CS1150, one TENMAT's top performing Refractory Products, is used as pouring nozzles and replaced conventional calcium silicate and cast iron tubes for flow control of liquid aluminium.

NITRASIL, an engineering ceramic, exhibits high mechanical strength and exceptional wear resistance capabilities. The material is primarily used for applications in contact with molten metals like rotary degassing equipment, molten aluminium handling, zinc atomisation systems, non ferrous metal handling and others.

Whether it is in the operation or maintenance of process equipment TENMAT's products offer cost effective solutions to improve energy utilisation, decrease operating costs, reduce weight, and increase life cycle operation.

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