The efficacy of metals like Aluminium, Zinc, Iron, Copper, Lead and Mercury was discovered thousands of years ago. Their unique properties and characteristics such as durability, strength, malleability and conductivity are of significant importance in a wide array of modern products. Metals are known to be precious natural resources of Earth. Metal deposits are non-renewable resources that will result in extinction if utilised at the present rate. This is why we must emphasize the recycling of metals that are parts of the municipal waste stream.
The reason metals are so efficient is that they can be recycles without losing any of their important properties. Insufficient retrieval of metals from consumer and industrial waste increases the pressure on the non-renewable resources of the Earth that they are extracted from. Dumping an excess of metal can also have a negative impact on the environment due to the metallic particles released in to the ecosystem. Recycling metals from the waste stream is not only vital in the protection of all valuable resources, but also the protection of the environment.
Our rubbish, or municipal solid waste (MSW) is generally made up of things we commonly use and then throw away. Things such as packaging, food scraps, grass clippings, sofas, computers, tires and refrigerators may have a high abundance of metal material inside of them, able of being recycled and recovered for future use. Over 75% of waste is recyclable, whether it be metal scraps, paper or cardboard, though we only recycle about 30% of it.
In the USA, Total MSW generation has gone from 208.3 million tons of recycled metal in 1990, to 249.9 in 2010. An increase of 41.6 million tons of recycled metal in only 20 years is as much an improvement as it is a sign, that with time, our world has the potential to be a better place, at the cost of our contributions to making it more than adequate for all those who occupy it. Also in the USA, 7 million tons of metals recycled reduced greenhouse gas emissions at equivalent of removing 5 million cars from the road for one year.
Due to the Australian and New Zealand (ANZECC) Environment and Conservation council endorsed National Kerbside Recycling Strategy, Australia became one of the first countries to have a national voluntary recycling plan giving commitments at all levels of industry. This (ANZECC) consisted of a large range of voluntary recycling targets for the major packaging industries. This Strategy also extended the kerbside recycling scheme to at least 90% of households in major urban areas. The rate of household recycling in Australia doubled during 1990 to 1993.
In 2002-2003, the Productivity Commission found that only 5% of municipal waste comprised of metals. Metal's abundance in 10.6 million tonnes of Municipal waste is around 530, 000 tonnes. This is a lot of tonnes. However, metals are in the 35% of recycled materials renewable from the Commercial and Industrial Waste Management in Australia. CIWM is by far the largest waste stream, comprising of almost 50% of all waste generated in the state (NSW).
The Boomerang Alliance (BA) estimated that the recovery of renewable and non-renewable materials such as paper, cardboard, metals, plastic and glass would save 7.6 million tonnes of CO2 per annum, 173 gigalitres of water per annum, and improved air quality in the vicinity of 19.9 billion units of Smog Precursors (gCcH4-e) (Similar to removing 4.6 million cars from Australian roads for a year). Recycling one tonne of steel conserves 2,500 pounds of iron ore, 1,400 pounds of coal and 120 pounds of limestone. Recycling aluminium conserves up to 8 tons of bauxite ore and 14 megawatt hours of electricity.
Bauxite, an aluminium ore, is used in cement, beverage cans, dishwashers, siding on houses, make-up, chemicals, and other aluminium products. Recycling aluminium saves approximately 95% of the energy it takes to produce more aluminium from bauxite, so about 30% of aluminium products are made from previously recycled items. It is also an efficient process, which takes as little as 60 days for a can to be collected, melted and made into a new can.
Recycled copper is worth up to 90% of the cost of the original copper, it is also cheaper to recycle copper than it is to mine and extract it. Recycling one tonne of copper saves fifteen percent of the energy used in extracting and producing the same amount of virgin copper. Less energy means a saving in fossil fuels that are also non-renewable. Less energy used also means less emission of greenhouse gases into the environment.
Ferrous metals are metals that contain iron, including wrought iron, cast iron, steel and stainless steel. Recycling ferrous metals diverts them from landfill, reduces the need to extract and manufacture raw materials and contributes to significant savings in greenhouse gas emissions. Recycling steel, uses 75% less energy than making steel from raw materials. All types of steel are 100% recyclable and can be recycled an infinite amount of times.
While the recycling rate of zinc depends mainly on the collection rate of zinc-containing products at the end of their life, over 90% of these collected products are recycled. Zinc-coated steel and other zinc containing products are slow to enter the recycling circuit due to the very nature of their durability. The life of zinc-containing products is variable and can range from 10-15 years for cars or household appliances, to over 100 years for zinc sheet used for roofing. The level of recycling increases each year, in step with progress in zinc production and recycling technology.
Lead enjoys one of the highest recycling rates of all materials in common use today. This is a result of its fundamental properties, good design and the ways in which it is used, which make lead based products easily identifiable and economic to collect and recycle. Since lead is a naturally occurring element, the quality of the recycled lead is identical to that of primary metal from mining. Today about 80% of lead is used in lead acid batteries, all of which are readily recyclable. Together with a number of other smaller volume metallic applications such as radiation shielding, cable sheathing and various specialised applications, such as earthquake dampers, this means that about 90% of all lead is used in readily recyclable products, and almost all of it is recycled.
A variety of lamps used in Australia require mercury to operate. Generally, the higher the power usage or wattage, the more mercury required to operate the lamp. Mercury-containing lamps are not manufactured in Australia, they are all imported. Approximately 52 million mercury-containing lamps, of all types, were imported into Australia in 2008. This figure will increase with increased usage of Compact Fluorescent Lamps (CFLs).