8-31-15
Litter cont.
Items
1. Tin cans – 99% steel, layer of tin on outside, this prevents can from corroding, it is called a bimetal can (made up of 2 metals)
Became popular about 100 years ago
Iron – rust process is called oxidation (loss of oxygen)
Over time, the can will be reduced to rust particles
Corrosion will be affected by the following:
Abrasion
Water
Salt
Most tin cans (cans made from steel) are easily recycled by scrap dealers
About 64% of the steel annually produced in North America come from previously used steel
Takes about 50 years for steel to decompose
2. Aluminum (comes from a substance called Bauxite AL2O3 (aluminum oxide)
In 1960’s began using aluminum in soda cans because of the pull tab
Recycling reduces the need to mine Bauxite (one of the most abundant materials in the earth’s
crust)
Bauxite is made from the weathering process of granite
Found naturally in Australia and Guinea
Recycling aluminum takes 90-95% less energy than it takes to mine and refine Bauxite
Takes 60 days to recycle and get it back on the shelf
Aluminum resists corrosion
Aluminum forms a protective layer of aluminum oxide – protects AL inside for 500 years