modern refractories for the casting lines materials and

$: Modern Refractories for the Casting Lines Materials and$
DRACHE

Modern Refractories for Casting Lines

www.drache-gmbh.de May 2013 Jochen Schnelle

Modern Refractories

for the Casting Lines

-

Materials and Application

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Overview of Materials

• Fused Silica – for precast shapes (launder segments,

filterboxes etc.)

• High Alumina Castable (for large shapes with long metal

contact times)

• Calcium Silicate – for machines parts (transitions plates,

launder dams etc)

• Insulation – how to improve performance and minimize heat

the heat loss of relined vessels

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Fused Silica

• Fused Silica is the most simply modification of Silicon

Dioxid ( SiO2), arise by a reaction between Silicon and

Oxygen.

• The result is a non crystalline, three-dimensional structure,

which has a high using temperature and a very low thermal

expansion.

• Fused Silica is melted in electric furnaces from quartz sand.

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Fused Silica

• Parts made out of Fused Silica could be used especially for

the production of aluminium billets, ingots and rolling slabs.

• Fused Silica in general is pre fired, ready to use. So no

additional treatment like drying or machining is necessary.

• An additional property for the usage in liquid aluminium is

the excellent non wetting character.

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Technical Data Fused Silica

• Max. application temperature: 1000 °C

• Chemical Analysis: approx. 85 % SiO2

approx. 10 % Al2O3

approx. 5 % CaO

traces Others

• Bulk density: 1900 kg / m³

• Thermal expansion: approx. 1,1 x 10-6 K-1

• Thermal conductivity: 600°C = 0,53 W/mK

700°C = 0,55 W/mK

800°C = 0,58 W/mK

• Bending strength: approx. 8 MPa

• Cold crushing strength: 40 – 50 MPa

• Molten aluminium testing: 72h / alloy 7075 / 816°C

No penetration, rating : excellent

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Single Filterbox Liner

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Complete Filterbox

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Double 20“ Filterbox Liner

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Double 23“ Filterbox

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Custom-shaped 20“ Filterbox

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Liner for a FDU Degasser

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High Alumina Castable

High Aluminium Castables are a refractory material, which is

originally used in certain furnace sections.

Advantages:

• high strength

• high erosion resistance

• high resistance to Aluminium penetration for extended

contact times

Disadvantages:

• low resistance to thermal shock

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High Alumina Castable

Drache uses the same production route for high Alumina

castables like for Fused Silica:

• mixing of raw materials / bulk materials (with water) in an

intensive mixer

• casting into moulds

• pre-drying at ambient conditions

• enforced drying / firing in a kiln

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Precast Section for a DBF

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Relined DBF

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Calcium Silicate

Calcium Silicate is a ceramic material which characterized by

its low thermal conductivity, good strength as well as a very

good machinability.

Calcium Silicate is either available as board material or as

fully machined shapes.

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Calcium Silicate

Drache offers four grades of Calcium Silicate:

DKS 100 - carbon fiber reinforced

DKS 150 - cordierite particle increased

DKS 200 - carbon fiber reinforced

- high quality

DKS 250 - M1A Promat material

- thermal pre-treated

- without reinforcement

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Calcium Silicate

Applications:

launder dams

header plates

spouts

Transition plates

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Calcium Silicate – Launder Dams

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Calcium Silicate – Header Plate

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Calcium Silicate – Transition Plates

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Insulation

Vessels relined with Fused Silica or High Alumina precast

shapes should be properly insulated, to minimize the heat loss

and achive the maximum performance from the precast

shapes.

Typical Drache insulation set-up:

• 40 or 50 mm of micropouros board

• Dri-Vive dry insulation granulate

• Carath insulating refractory concrete

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Filterbox lined with WDS Board

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DBF lined with WDS Board

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Further Services

Further services for precast shapes from Drache include:

• full engineering services

• fully customization of precast shapes

• heat loss calculations

• flow calculations (for launders)

• on-site installation and commissioning services

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