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COPPER

CONTINUOUS CASTING

SIFAX THERMAL DEVICES, S.L.

C/ Navas 20-H, Pol. Industrial Rio de Janeiro, 28110 - Algete, Madrid (Spain), tel: +34 91 806 36 31 email: info@sifaxtd.com

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COPPER INDUSTRY (Secondary Metallurgy)

Melting "Shaft" furnace

SIFAX offers a custom engineered solution for copper shaft, holding furnaces and launders. Vertical "shaft" furnaces operating temperatures of approximately 1200°C and can be reach higher temperature around the burners and tap hole area.

Copper Shaft Furnaces melts copper cathodes and first quality of recovery material. This type of operation usually requires a reducing environment with burners running rich.

ADCARNIT CU, modified nitride and oxynitride bonded silicon carbide developed by SIFAX is not wet copper metal whereas traditional oxide bonded silicon carbide is wet allowing penetration into the pores structure and subsequent thermal spalling.

In oxidizing atmospheres cuprous oxide (Cu2O) that is formed reacts with matrix oxides forming an oxidized layer on the refractory lining. This reduces the wetability contact angle allowing penetration of copper metal into the pores of the refractory shapes. Large contact angles prevent penetration into the pores. The cuprous oxide (Cu2O) reacts forming eutectics below the conditions of furnace operation:

Cu2O + SiO2 have eutectic at 1060⁰C

Cu2O + Al2O3 have eutectic at 1165⁰C

ADCARNIT CU blocks manufactured and supplied by SIFAX have an improved resistance against copper oxide attack and their significant higher mechanical strength, which gives superior impact and abrasion resistance, so it is an excellent choice for impact and non-reactivity shapes with melting copper and its alloys.

The advantages of ADCARNIT CU over traditional silicon carbide materials are:

- Increased mechanical strength at cold and high temperature - Increased impact resistance - Excellent chemical and oxidation resistance - Excellent resistance to thermal shock - Increased abrasion resistance

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SIFAX high-performance ADCARNIT CU linings ensure a long, trouble-free service life. Some key design features of SIFAX linings:

- Thicker hot face shapes lining - Tongue and groove hearth shapes - One-piece tap hole blocks - Two pieces burner block system - Specific mortars to reduce joint erosion - Design pre-formed castables sub-hearth for easy installation

ADCARNIT CU design concept minimizes slag formation and impurity inclusions, thus yielding a potentially cleaner metal. This innovative design has helped to improve the overall lining life of a standard shaft furnace at least twice, with an expected service life of 3-4 years with minor repairs sporadically.

Physical and mechanical specifications of ADCARNIT CU and ADCARSIL CU

SIFAX PRODUCT ADCARNIT CU ADCARSIL CU

Property Standard Unit SiC-Si3N4+Si2ON2 SiC-SiO2

Maximum temperatura use oC 1590 1500

Modulus of rupture (1250 oC) EN 993-7 MPa 65 30

Crushing strength EN 993-5 MPa 165 120

Modulus of elasticity EN ISO 12680-1 GPa 160 110

Thermal conductivity (1250oC) EN 993-15 W/(m⁰K) 15,5 12,5

Abrasion resistance EN ISO 16282 cm3 <1,5 <3,0

Thermal shock resistance excellent Very good

Lineal thermal expansion (20-1400oC) EN 993-10 10-6/oC 4,9 4,8

Mean specific heat (20-1000 oC) EN 1159-3 J/Kg⁰K 1050 1050

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STANDARD DESIGN SHAFT FURNACE

1-CHARGE AREA Higher thickness arch bricks in ADCARNIT CU to reduce horizontal joints and minimize erosion on walls

2- TRANSITION AREA High thick arch bricks in ADCARNIT CU

4- CORBEL AREA Highly recommend the use of beveled arch shape in ADCARNIT CU and middle thickness to reduce the damage often caused during charging

3- COMBUSTION AREA It is the most critical area of the furnace due to the high temperatures >1200ºC, erosion and chemical corrosion, where large shapes and two-piece burner block systems are used in ADCARNIT CU

5- HEARTH It is recommended tongue and groove shapes in ADCARNIT CU of higher thickness for good erosion and corrosion behaviour

6- TAPHOLE AREA This area is one of the most critical to extreme conditions of abrasion and chemical corrosion. Large hole- block to remove mortar joints is recommended in one piece tap out tile easily replaceable in ADCARNIT CU

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CHARGE AREA

ADCARNIT CU arch shapes 220mm thickness

TRANSITION AREA

ADCARNIT CU arch shapes installation and ADCAST-ADLITE back-up insulation

ADCARNIT CU arch shapes 150 mm thickness and burner blocks

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Burner block in ADCARNIT CU

COMBUSTION AREA

REDUCTION AREA

Reduction area overview ADCARNIT CU beveled arch shape 150 mm thickness

ADCARNIT CU burner block installation

ADCARNIT CU arch brick 150 mm thickness

ADCARNIT CU burner block

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TAPHOLE AREA

ADCARNIT CU tap out piece ADCARNIT CU taphole area

ADCARNIT CU tap out installation

HOLDING FURNACE (Treatment)

The design of this type furnace usually installs arch shapes and/or other formats, and specially shaped blocks for the inlet and outlet skim door, vent door and burner area. The recommended lining is based on ADCARNIT CU and designed for a tight fit and structural integrity at operating temperature. However, ADCARSIL CU with a glazed surface and low permeability can also be used for phosphorous-copper alloys (14-15% phosphorus).

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HOLDING FURNACE

LAUNDERS

The casting channel elements in different designs (U-shape or C-shape) with tongue and groove systems of ADCARNIT CU (modified nitride bonded silicon carbide) and ADCARSIL CU (oxide bonded silicon carbide with anti-wetting components) are backed up by high-temperature monolithic materials (unshaped) of type ADTIX-ADCAST-ADLITE and insulating ceramic board or fibre, all within a steel frame. Thanks to close tongue and groove system fitting the entire whole assembly offers a smooth and excellent metal resistance on the working hot face.

TAP OUT

HOLDING FURNACE DESIGN

Taphole area

ADCARNIT CU o ADCARSIL CU

ADTIX-ADCAST-ADLITE

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LAUNDERS

SIFAX also supplies monolithic (unshaped) and mortars developed specifically for joining shapes and blocks, and plastic materials for repair and patch, such as:

- ADMOR SiC and SiC QP: Dry, heat setting bonding and/or self-setting/chemically bonded mortar developed to minimize joint shrinkage and corrosion resistance of molten copper and its alloys.

- ADPLAST 80 SiC QP: Plastic material chemical bonded ready to use for repair and/or patch with excellent properties against erosion and chemical corrosion of molten copper and its alloys.

ADMOR SiC y ADPLAST 80 SiC QP

Tongue and groove launder system

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