Metal recycling involves the recovery and processing of scrap metal from end-of-life products or structures, as well as from manufacturing scrap, so that it can be introduced as a raw material in the production of new goods. This may involve a number of steps such as identifying, recovering, refining and reclaiming precious or non-precious metals.
Why refining and recovering metals is important
Recycling in general has become increasingly important in our society. We are accustomed to hearing the three R’s of recycling (reduce, reuse, recycle) to include paper, plastics, bottles, cans, and cardboard; however, many people do not know that you can recycle precious and non-precious metal as well.
There is a wide range of reasons why you should refine and recover your metal rather than wasting it. Recycling metal reduces pollution, saves resources, reduces waste going to landfills and prevents the destruction of habitats from mining new ore. Scrap metal is a continuous resource. Because it can be re-melted and reshaped into new products countless times, recycled metal is a resource that will never be depleted. The production of new metal releases a far greater amount of greenhouse gas emissions compared with making products from recycled metal. These emissions may influence climate change and may also cause harmful levels of air pollution in cities, resulting in potential respiratory health problems for the residents.
Recovering precious metals from end-of -life products can also generate a good extra income. During these uncertain economic times investors have fallen back to the more stable commodities market, with precious metal prices (Gold and Silver in particular) rocketing as a result. Gold, silver, platinum and other precious metals can still be mined from natural sources. But mining is very costly and in many cases, it is becoming easier and more cost-effective to recover those metals from devices that already contain them. A ton of recycled cell phones actually contains more gold than a ton of gold ore that comes from most mines.
How to identify metals to refine
You can easily use a magnet to separate ferrous from not ferrous metals. Ferrous metals contain iron which in most cases makes it magnetic. If a metal is non-ferrous it doesn’t have iron in it, so it won’t stick to a magnet. Various other tests can be made to determine the type of metal and if it can be recycled or not. The most common is the appearance test, which consists in studying the physical features of the metal. Sometimes this can be quite difficult as there are metals that look similar to each other. Gold and brass, for instance, are often being confused as they have a very similar colour. After a deeper inspection, however, you should notice that gold is heavier and brass produces a bell like vibrating sound if you try to hit it. Other useful tests are the fracture test, which helps you identify a metal by analysing its broken part, and the spark test, which looks at the spark produced by touching the metal to a grinder.
To identify precious metals such as gold, silver and platinum you can also follow some simple rules.
1. Precious metals aren’t magnetic — if the metal attracts the magnet, you know it must be an alloy mixture and not a precious metal.
2. Gold won’t scratch glass — real gold is soft and malleable and won’t leave a scratch on a glass surface like other metals similar to gold do. You can also try to run the gold piece on a section of tile. If the piece leaves a black mark, it doesn’t contain pure gold. High-quality gold pieces will leave a yellow or gold streak on the tile’s surface.
3. Silver feels warm to the touch — silver will feel closer to your body temperature when you hold it in your hand and it is also a great heat conductor.
4. Precious metals rub off differently — if you rub an item against a cloth, real gold will leave no mark. With silver items, expect just the opposite. Real silver or silver-plated items will turn the cloth black.
Common metals that can be recycle and how to identify them
– Aluminium One of most unique qualities of aluminium is that it is quite light — three times lighter than iron. Aluminium is also completely non-magnetic, so it won’t stick to even the strongest of magnets. Aluminium doesn’t rust, which makes it very durable. Typical use in: Drink cans, Window frames, Cooking pots, Food packaging, Boats and aircrafts, Overhead power lines
– Copper Copper has a natural pink tone that can darken to look red, yellow or orange over time. When exposed to excess water or oxygen, copper can turn green or black in places where it has been excessively handled. Copper is notoriously soft, so it can be difficult to keep a piece perfectly smooth when working with the copper. If the copper piece is thin enough, you may even be able to bend it with your bare hands. You may also knock on the piece and listen to the sound that it makes. Real copper will have a deep and mellow sound, as opposed to brass, which can be high-pitched and tinny. Typical use in: Wires, Motors, Roofing, Plumbing, Cookware and cook utensils, Rainspouts
– Brass The word brass refers to any alloy that contains copper and zinc. Different proportions of these metals produce different colours, but the most common types of brass have a muted yellow colour, or a yellow-brown appearance similar to bronze. These brass alloys are widely used in machined parts and screws. The hundreds of different combinations means there is no single way to identify all brass. That said, the colour of the brass is usually distinct enough to separate it from copper. Typical use in: Lamp and plug fittings, Electrical terminals, Locks, Marine engines, Valve guides, Door lock components, Wind instruments, Radiator cores, tubes and tanks
– Gold Gold is a shiny yellow colour and does not have an oxide. Golds melting point is 1064.18°C (1947.52°F). It is very soft and is very heavy. It also has a high electrical conductivity (more electricity can pass through it) which means that the connectors on many cords have gold plating. Gold is nonferrous so it won’t stick to a magnet. Typical use in: Jewellery, Coinage, Watches, Electrical connectors, Artificial limb joints, Dentistry, Computers, Electronics.
– Lead is a dull grey when unpolished but it becomes a lot shinier when polished. Lead has a relatively low melting point, 327°C (621°F). Lead is nonferrous and it is even heavier than iron It’s a relatively soft metal, and can be carved with a pocket knife and is used in pencils. It is commonly used on roofs and in construction. Typical use in: Pipes, Flashing, Gutters, Downspouts, Conductor Heads, Ammunition, Cable sheathing, Weights for lifting, Weight belts for diving, Radiation protection.
– Steel Steel is a dense, relatively heavy material that easily rusts, so the surface must be painted, galvanized, cleaned often, encased in concrete, or protected in some other way. Freshly grinded carbon steel looks shiny and metallic; otherwise it has a dull, dark (but still metallic) colour. On a grinder, steel produces lots of sparks. As a rule, the greater the spark bursts, the higher the carbon content of the steel. Typical use in: Bars, Rods, Rails, Wires, Pipes, Automotive parts, Appliances, Fittings, Flanges, Valves
– Silver is a soft, ductile, malleable, lustrous metal. It has the highest electrical and thermal conductivity of all metals. Silver is stable in oxygen and water, but tarnishes when exposed to sulphur compounds in air or water to form a black sulphide layer. Typical use in: Jewellery, Mirror manufacturing, Dental fillings, Silver nitrate films for photography and radiography, Electrical contacts, Silver-cadmium batteries, Silver-zinc batteries.
At All Waste Matters we have over 50 years of experience in specialist refining of precious metals in a number of industry sectors. We can help you turn seemingly insignificant scraps into profit for your company. We are both silver refiners and gold refiners and thanks to our extensive expertise we can ensure we will return the maximum value of your material.