Metallurgical Processing of Aluminium Scrap

admin 3950 Views

Discover the principles and considerations of metallurgical processing of aluminium scrap in this comprehensive part of the book “Handbook of Aluminium Recycling”.

Part III in the book “Handbook of Aluminium Recycling: Mechanical Preparation, Metallurgical Processing, Heat Treatment”
by Christoph Schmitz

Contents of Part III

Metallurgical Processing of Aluminium Scrap

Melting process

Principles considerations
Oxidation during melting
Melting additives
- Usage of salt in the rotary drum furnace
  - Application of salt
  - Protection of metal
  - Stripping of oxides and coagulation
  - Dissolving and suspension of other materials
  - Characteristics of salts
  - Characteristics of slag
  - Summary and recommendations
- Usage of chemicals in the hearth furnace
- Covering of melt
- Refining
- Grain refining
- Wall cleaning
- Treatment chemicals
Summary of process loss
- Melt loss
Energy consumption
Alloying

Overview of melting technologies

Classification of furnaces according to design characteristics and application
- Basic requirements
- Classification of furnaces
- Design criteria and application of furnaces
  - Hearth furnace
  - Twin chamber furnace
  - Dry hearth furnace
  - Tower furnace
  - Rotary drum furnace
  - Crucible furnaces
  - Crucible induction furnaces
  - Channel induction furnaces

Furnace technology

Energy balance and efficiency
- Basics of thermodynamics
  - Energy
  - Enthalpy
  - Heat capacity
  - Heat flux
- Heat balance
- Efficiencies
  - Combustion efficiency
  - Furnace efficiency
  - Total efficiency
- Specific energy consumption
- Introduction of heat
- Fuels
- Reaction of combustion
- Combustion air requirements
- Combustion products
- Induction heating
- Resistor-heating
Transmission of heat
- Heat conduction
- Convective heat transfer
- Radiant heat transfer
- Total heat transfer
Burner technology
- Fuels
- Burners
  - Gas burners
  - Oil and dual fuel burners
- Combustion systems
  - Efficiency of combustion systems
  - Comparison of the efficiency of different combustion systems
- Oxy-fuel burner systems
  - Oxy-fuel burner principle
  - Flameless oxy-fuel burner
  - Aluminium melting with oxy-fuel
  - Emissions
- Regenerative burner systems
  - System principle
  - Special ultra low-NOx burners for regenerative systems
  - Regenerators
  - Maintenance of regenerative burner systems
- Oxy-fuel technology
  - Oxy-fuel combustion
  - Heat balance
  - CFD modelling
- Energy losses
  - Metal discharge
  - Stack losses
    - Recuperators
    - Regenerators
    - Incinerators
    - Charge pre-heating
    - Tower furnaces
  - Wall losses
  - Door losses
- Furnace design
  - Mechanical structure, general
    - Hearth furnaces
    - Twin chamber furnaces
    - Oval furnace
    - Rotary drum furnace
    - Induction furnace
    - Hydraulic equipment
    - Auxiliary equipment
  - Refractory lining
    - Requirements of refractory linings
    - Groups of refractory materials and their raw material
    - Raw materials
    - Types of refractory material and manufacture
    - Curing
    - Refractory design
    - Design and installation

Casting technologies

General considerations
- Product mix
- Quality requirements
- Casting machines
Heat balance
- Casting temperature
- Cooling conditions
Design of casting equipment
- Casting circles
- SOW casting system
- Ingot casting machine
- Ingot stacker
- Vertical direct chill casting machine
- Horizontal direct chill casting machine
- Strip casting machine
- Rod casting machine
- Pelletizing table
Water treatment

Metal treatment

De-gassing systems
Some basic considerations
Inline degassing units
Furnace-installed systems
Metal filtration

Homogenizing

Metallurgical considerations
Batch-type homogenizing plant
Homogenizing furnace
- Furnace structure and concept
- Control system
Cooling chamber
Charging machine
Stacking and de-stacking station
Continuous homogenizing plant
- Operating description

Environmental control

Design criteria
- Gaseous emissions
  - Combustion products
  - Products of evaporation
  - Carbonization products
  - PCDD/F
- Clean gas requirements
- Water
- Noise
- Production waste
Fume collection and health precautions
Waste gas treatment
- Casting furnaces
- Melting furnaces
- Waste gas system
- Additives
- Cloth filter
- Wet scrubber
- Centrifugal separator (cyclone)
- Quenching chamber and incinerator

Process control

Sensors and actuators
- Sensors
- Actuators
Control architecture level
- Interlockings
- Automatic control loops
  - Controls for combustion system capacity
  - Fuel ratio control
  - Burner safety
  - Motion control
- Control hardware
Control architecture level
- Process optimization
- Melting optimization

Quality assurance

Quality management
Incoming material
- Incoming scrap
- Additives
- Products
Testing methods
- Metal analysis
- Hydrogen content
- Non-metallic inclusions
- Additional testing methods

Safety

General safety aspects
Personal safety
General plant safety
- Electrical equipment
- Occupational disease prevention
- Fire protection
- First aid
- Furnaces
- Charging
- Liquid metal handling
- Equipment

PREVIEW

Get the book