Asbestos-free Mica slip plane for ferrous and non-ferrous foundries
An effective application for coreless induction coil furnaces
Mica-based linings are flexible, easy to handle, and have replaced asbestos in most countries of the world hence contributing non-hazardous products to maintain the health of foundry personnel.
Non-toxic mica rolls are delivered 1m wide and 25m long and serve as:
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Slip-Plane Glass fiber reinforced mica with high tensile strength,
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Safety-Layer protecting the coil against refractory material movements
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Separating-Layer gas diffusion barrier
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Isolation-Layer electrical and thermal protection
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Protection Layer compensates bath movements (mainly vertical)
Main products:
Newform Combi G (Mica/High-temperature CaSi-paper). 0.95” (2,4mm) thick
Newform Foil G (Phlogopite mica, glass fiber-reinforced) 0.16” (0,4mm) thick
Sensitive, water-cooled copper coils in induction furnaces are protected by a concrete wall (coil grout) against refractory (thermal insulation). Removal of the worn refractory material with a hammer drill is expensive and may cause damage. A tear resistant, mica-based, layer enables separation of residual (sintered) refractory from the concrete wall when pushed out and in such protects the coil, elongates service life of the refractory in the crucible and reduces maintenance costs.
When lining coreless induction coil furnaces, SiO2-based refractory material is inserted locally into the crucible and compacted to form the thermal insulation of the coil from smelt. The approximately 10cm thick insulation degenerates, depending on the nature/aggressiveness of the smelt, after some 200 applications - 2-6 weeks with melting (usually medium frequency) furnaces.
Removal of the old, used, mass and slag and following relining of a crucible furnace with heat insulation demands caution and experience. Getting the coil grout surfaces sufficiently smooth, so that no defects in the coil wall arise, is labor- and time consuming.
Newform provides an asbestos-free and biodegradable mica-based layer to serve as slip-plane of used refractory during demolition. The slip-plane material consists of glass fiber reinforced mica paper (ca. 0,3mm to 0,5mm thick) laminated with heat-resistant silicon binder. It may be combined with 2mm Calcium-Silicate-paper when required at larger furnaces, where the wall (coil grout) is rather uneven.