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  • What happens to aluminum in the recycling process?

    Aluminium recycling is not new.   Aluminium recycling is the process by which scrap aluminum can be reused in products after its initial production.  It has been a common practice since the early 1900s and extensively capitalized during World War II.    It was, however, a low-profile activity until the late 1960s when the exploding popularity of aluminium beverage cans finally placed recycling into the public consciousness.

    The process involves  re-melting the metal.  This is far less expensive and energy intensive than creating new aluminium through the electrolysis of aluminium oxide (Al2O3), which must first be mined from bauxite ore and then refined using the Bayer process. Since recycling does not transmute the element, aluminium can be recycled indefinitely and still be used to produce any product for which new aluminium could have been used.

    Recycling aluminium uses about 5% of the energy required to create aluminium from bauxite.

    The recycling of aluminium  produces significant cost savings over the production of new aluminium ….even when the cost of collection, separation and recycling are taken into account.   Over the long term, even larger national savings are made when the reduction in the capital costs associated with landfills, mines and international shipping of raw aluminium are considered.  Recycling aluminium uses about 5% of the energy required to create aluminium from bauxite. 

    For this reason, approximately 31% of all aluminium produced in the United States comes from recycled scrap.  The amount of energy required to convert aluminium oxide into aluminium can be vividly seen when the process is reversed during the combustion of thermite or ammonium perchlorate composite propellant.

    Used beverage containers are the largest component of processed aluminum scrap, with most UBC scrap manufactured back into aluminum cans.  Other sources for recycled aluminium include aircraft, automobiles, bicycles, boats, computers, cookware, gutters, siding, wire, and many other products that need a strong light weight material, or a material with high thermal conductivity.

    After collection, the scrap aluminium is separated into a range of categories such as  irony aluminium (engine blocks etc.), clean aluminium (alloy wheels) and then cleaned in preparation for the next step.  Tthe specification of the required ingot casting it will determine on the type of scrap used in the start melt.  The scrap is then taken to a reverberatory furnace (other methods appear to be either less economical and/ or dangerous) and melted down to form a “bath”.  The re-melt process removes any coatings or nk that may be present on the aluminum.  The molten metal is tested using spectroscopy on a sample taken from the melt to determine what refinements are needed to produce the final casts.   After any necessary refinements have been added the melt may be tested several times to be able to fine tune the batch to the specific standard

    Once the”recipe” of metal is correct, the furnace is tapped and poured into ingot moulds, usually via a casting machine. The melt is then left to cool, stacked and sold on as cast silicon aluminium ingot to various industries for re-use.

    There is also a secondary recycling process for aluminum.   White dross from primary aluminium production and from secondary recycling operations still contains useful quantities of aluminium which can be extracted industrially.  The process produces aluminium billets, together with a highly complex waste material.  This is a difficult to manage waste because it reacts with water, releasing a mixture of gases (including, among others, hydrogen, acetylene, and ammonia) which spontaneously ignite on contact with air.   Contact with damp air results in the release of large quantities of ammonia gas. Despite these difficulties, the waste has found use as a filler in asphalt and concrete.

     

     

    Of course there are creative ways to recycle also.  Check out what some people have done to make good use of their aluminum.CERT-34104 aluminum recycling rim table bike wheel trellis

     

    Aluminum is an amazing metal!

     



  • Facts About Brass

     

    Brass Recycling – Brass is not an element metal by it’s self. But since it’s use is so common and it is often described as it’s own metal, it deserves its own section. The base element found in this type of metal is copper alloyed with a high percentage of zinc. You will also find information here on a couple of commonly bought bronze alloys. Common terms and information in recycling this type of metal and its alloys are given below.

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    Yellow Brasspicture of yellow brass items

    The most commonly used of all brasses and its alloys. It is used in household plumbing including popular items such as your faucets and “under the sink” plumbing. Most of the keys we use will also be yellow brass. Although many different alloy percentages can be found, this type of metal usually contains around 60% to 70% copper, 30% to 40% zinc and trace amounts of lead and tin. This type gets it’s name because of the very apparent yellow color. The  prices often reflect the price of copper,however demand is also key, as with any alloyed metal.

    Red Brasspicture of what red brass looks like

    This brass is still commonly recycled, although diminishing in use. It has a  reddish pink tint which gives it  its name. The red tint is due to the high amount of copper that will usually will be found. This type of metal is commonly made up of 85% copper, 15% zinc and very small traces of lead and tin. Common uses of red brass are sprinklers and shut off valves, but many other items that can be found.

    Semi-red Brasspicture of what semi red brass might look like

    Semi-red brass has replaced red brass as we’ve known it. It is made of a cheaper element mixture which is  equally as useful. The common element alloys are 80% copper, 10% zinc, 5% tin, 2-3% lead and other trace elements. It’s common uses are similar to red brass which include shut off valves, sprinkler’s and other not so common items.

    A less common type of metal that has similar alloyed elements as brass, is bronze. The 2 most used are defind as Aluminum Bronze and Manganese Bronze. Aluminum Bronze is around 90% copper, 7% aluminum, 2-3% iron and traces of other elements. Manganese Bronze is 58.5% Copper, 39% Zinc, 1.4% Iron and small traces of other elements.

    a picture of what bronze metal would look like