The Chemistry Of Metal Corrosion

BCM Scrap Steel • June 5, 2025

Recycling metal is a key part of reducing waste and conserving resources. Unlike many materials, metal can be reused multiple times without losing its strength or quality. This makes it one of the most valuable and sustainable materials in circulation today. Whether it’s from old appliances, construction waste, or machinery, scrap metal goes through a series of well-defined steps before it can be reused again. Each stage plays a role in turning discarded items into raw materials ready for new production.

Understanding how scrap metal is processed helps highlight the importance of proper recycling and its role in supporting industries, reducing landfill waste, and reducing environmental impact. Here’s a look at the processes involved in transforming scrap into something useful once again.

The journey of scrap metal begins with its collection. Materials come from a range of sources, including households, construction sites, farms, factories and even automotive yards. Whether it’s an old washing machine or excess steel from fabrication, the recycling process can’t start without responsible disposal.

Common sources of scrap metal include:

• Whitegoods like fridges, washing machines, and stoves
• Demolished structures and renovation waste
• Old machinery and farming equipment
• Vehicles, car parts, and batteries
• Discarded tools, wires, and fencing materials



Collection services provided by recyclers in Emerald make it convenient for locals to responsibly dispose of unwanted metal, contributing to a cleaner environment and more efficient resource reuse.

Once the metal arrives at a recycling centre, it needs to be sorted based on type and quality. Not all metals are processed the same way, so a critical early step involves classifying scrap into ferrous and non-ferrous categories.

Sorting typically involves:

• Magnetic separation – Magnets are used to pull out ferrous metals like iron and steel.
• Visual inspection – Experienced workers assess materials by colour, weight and corrosion.
• Density & conductivity testing – Advanced sensors may be used to identify specific alloys or metals.



Sorting correctly from the outset ensures greater efficiency in the later melting and refining stages. It also helps recyclers comply with strict industry standards when preparing metals for manufacturers.

After sorting, the metal must be reduced in size to improve handling and furnace efficiency. This stage prepares the material for melting by making it more uniform and transport-friendly.

Common processing techniques include:

• Shearing & cutting – Large sections are mechanically chopped into smaller pieces.
• Baling – Lightweight metals such as aluminium are compressed into dense cubes for easier transport.
• Shredding – Steel and other bulk items are shredded into flakes or strips, increasing surface area for faster melting.



This stage also includes removing non-metal components like rubber, insulation or paint, where applicable.

Melting is a key process that turns metal scrap into reusable material. Due to varying melting points, each type of metal—steel, copper, aluminium—requires a different furnace. Facilities like those in Emerald operate furnaces designed to maximise energy efficiency and minimise emissions.

Key points about melting:

• Furnaces are segregated by metal type to avoid contamination.
• Recycled steel melts at a lower energy cost than mining virgin ore.
• This stage often recycles its own emissions through filtration systems.



The controlled environment ensures that impurities can be separated from molten metal, improving quality for reuse.

Once melted, metals often require purification to meet industry-grade standards. This is especially important for recycled scrap destined for structural applications or precision manufacturing.

Purification techniques may include:

• Electrolysis – Commonly used for copper, this removes impurities using electric current.
• Chemical treatments – Added agents help neutralise or bind to contaminants.
• Magnetic purification – Helps eliminate unwanted magnetic elements.



During this stage, alloy composition may also be adjusted to meet specific customer requirements, such as increasing the carbon content of steel or removing excess zinc from brass.

After purification, molten metal is cast into usable shapes. Depending on future use, this could mean blocks, ingots, sheets or even rods. Controlled cooling ensures uniformity and strength.

Recycled metal is commonly solidified as:

• Ingots – Large blocks ready for remelting in industrial foundries.
• Billets or slabs – These are used in rolling mills to make structural steel or sheet metal.
• Granules or pellets – Suitable for smaller manufacturing processes.



This makes the recycled metal easy to handle and suitable for transport to manufacturers who need raw material input.

Once shaped and cooled, metal is ready for the next stage of its lifecycle. Materials are distributed from the recycling site to manufacturers and fabrication plants across various industries.

Transportation processes usually involve:

• Coordinated logistics to minimise the carbon footprint
• Palletising, containerising or bulk shipping depending on form
• Regular supply chains for foundries, construction firms, and appliance makers



Local facilities are crucial in keeping materials moving efficiently through Australia’s industrial network.

The final stage sees recycled metal become part of something entirely new. Thanks to the processes above, metal that once formed part of a rusty gate or broken machine can be reborn as a beam, engine part or even a food can.

Examples of how recycled metal is reused:

• Steel – Becomes rebar, structural beams, or automotive components
• Aluminium – Used in beverage cans, window frames, or aircraft parts
• Copper – Essential for electrical wiring, plumbing, and electronics



This circular approach helps reduce the environmental and economic cost of mining virgin metals and extends the life cycle of finite natural resources.

At BCM Scrap Steel, we simplify the recycling journey. From collection to processing and resale, our metal recycling service in Emerald ensures scrap metal is used well, supporting the environment and Australia’s industrial supply chain. Whether you’re clearing out your yard, offloading surplus steel, or need a reliable recycling partner, we’re here to help.

Give us a call or visit our contact page to arrange a consultation or drop-off. Together, let’s make waste work smarter.