Conflict and Cans: Introduction
Background:
Your company, CanDo Enterprises, is a leading producer of tin cans
(or more accurately, tin-plated steel cans) for the food industry. Steel
is a mixture of iron and other metals. It is strong and durable but will
rust over time. A tin-coating protects the outside of the can from
corrosion. (A plastic coating protects the inside of the can.)
Recently it has come to your attention that your tin supplier has been
red flagged by the US government as a trader of conflict resources.
You fear your cans may be boycotted by conscientious consumers if
this news gets out.
CanDo Enterprises would prefer, for both humanitarian and financial reasons, to sever its
ties with tin and find a new material to coat its cans.
Conflict Tin:
The Democratic Republic of Congo (DRC) is a country rich in natural resources. The soil is
fertile and there is plenty of water flowing down the Congo River. Mining has unearthed
minerals such as diamonds, gold, copper, tungsten, cobalt, tantalum, uranium, and tin which
are highly valued commodities on the world market. But getting anything to market is a
challenge in a country with little infrastructure or rule of law.
The DRC was at war for nearly two decades and fighting continues in the eastern Congo
despite peace in other areas. This war, or series of wars, resulted in the deaths of more than
5.4 million people and the displacement of 2.7 million others. The DRC is one of the world’s
poorest countries; 88% of the population live on less than $1.25 a day.
The country is home to over 40 different militias and 200 different ethnic groups. Each group
has its own goals. Therefore, there is no “one” reason for the protracted period of conflict,
but certainly a corrupt central government, ethnic tensions, and a desire to control the
country’s vast natural resources all play a part. Sadly, most of the 5.4 million deaths have
been civilians who have died of starvation and disease. Almost half of the dead have been
children under the age of five.
One source of wealth for militias is the mining and sale of minerals such as the reddish-brown
cassiterite which is refined to produce tin. The DRC is the world’s 6th leading producer of tin
and supplies 5% of the world’s supply. Much of the money made in the DRC on tin, over
$115 million, has gone to its armed groups. And tin is only one of many “conflict” resources
mined and sold to support more violence and instability.
2
Local militias don’t have the resources to invest in the machinery of a modern mining
operation, and may be illegally squatting on land someone else owns. In these small mines,
the cassiterite (tin ore) is removed by hand. Miners, 30% of which are children under the age
of 14, crawl thorough pitch-black tunnels that can go as deep as 600 feet. Toxic gases can
build up in the narrow spaces and cave-ins are not uncommon. Workers eventually return to
the surface with a 110-pound bag of reddish rock.
Porters then carry the cassiterite on a 30-mile (2-day journey) to the nearest road where it
will be sold to a succession of middlemen before making its way to global markets. And tin
is not just for cans. As tin has replaced lead as the solder in electronics, the price of the metal
has skyrocketed. Despite the harsh (and sometimes deadly) working conditions, mining is
an attractive profession because there is money to be made.
Your Job:
CanDo Enterprises would like to replace the tin in its products with a material of
equally beneficial physical and chemical properties. It is your job to determine if
this is possible.
To do this, you will need a thorough understanding of elements, atoms, and the periodic
table.
Conflict and Cans: Getting to Know the Periodic Table
Elements are substances that are made of only one type of atom. The “type” of the atom
is determined by the number of protons in its nucleus. An atom with one proton is
hydrogen, no matter how many electrons or neutrons are in the atom. The number of
protons in an atom is also referred to as its atomic number. On the periodic table,
elements are listed by increasing atomic number.
Each box on the table provides key details about each of the 118 known elements. Each
element has a name – some are named after people, some after places, some names
describe a property of the element, etc.
Each element also has an abbreviation. “Sn” is
the
abbreviation for tin. (“Stannum” is the Latin name for
tin
and the root of the
abbreviation.)
The atomic number is generally at the top of the box
and it
the smaller of the two numbers. This is the number of
protons in the atom. The atomic number is also equal to the
number of electrons in a neutral atom.
The atomic mass is generally at the bottom of the box and is the larger number. The atomic
mass is measured in units of amu (atomic mass units). Protons and neutrons each have a
mass of 1 amu. Therefore, the atomic mass is the sum of the number of protons and
neutrons in the atom. (Electrons are so small they have almost no measurable mass.) Not
all atoms of the same element will have the same number of neutrons. Because these
isotopes of the element will have slightly different masses, the mass number is listed as an
average mass on the periodic table.
Quick Practice:
1. What is the abbreviation for fluorine? 3. What is the atomic mass of
aluminum? 2. What is the atomic number of helium? 4. What element has the
abbreviation C?
7
Elements on the periodic table are organized into rows and columns based on their
chemical and physical properties. Thus, an element’s position on the table can tell you a
lot about the element.
In the center of an atom is a dense nucleus that contains particles called neutrons and
protons. Around the nucleus, the electrons move rapidly in a space called the electron
cloud. In the cloud, each electron is assigned to a specific orbital
in which it can move.
The rows of the periodic table are called periods. Elements in the
same period have the same number of energy levels.
For example, every element in Period 1 (Row 1) has one energy level. A
neutral atom of hydrogen would have one electron in its first and only
energy level. A neutral atom of helium would have two electrons in its
first and only energy level.
All of the elements in Period 2 (Row 2) have two energy
levels. A neutral atom of lithium would have two electrons
in its first energy level and one electron in its second
energy level for a total of three electrons. An atom of neon
would have two electrons in its first energy level and eight in its second
energy level for a total of ten electrons.
Quick Practice:
1. Bromine (Br) has four energy levels. Name 2 other elements that would have four
energy levels.
2. How many energy levels would you expect an atom of cesium (Cs) to have?
The columns of the periodic table are called groups. The elements
in a group have the same number of electrons in their highest
energy level. These are called valence electrons. Because they
have
the same number of valence electrons, they react similarly in
chemical reactions.
Quick Practice:
1. Lithium (Li) has 1 valence electron. How many valence electrons would you expect
rubidium (Rb) to have?
2. Argon (Ar) has 8 valence electrons. Name 2 other elements that would have 8
valence electrons.
Conflict and Cans: Getting to Know the Can
I. Video 1: Plating the Can
https://www.youtube.com/watch?v=ctL6Oc0STUU
1. What is plating? Why is it done?
Plating is a layer of metal coating an object of a different type of metal. The purpose of
plating is to decorate or to make something stronger .
2. How is the steel surface prepared for plating?
First electro cleaned,dried then sandblasted then electroplating by tying strands of copper
weir to a copper frame.
3. What are some common plating metals?
Chrome,zinc,nickel,gold,silver,copper, and tin
4. How is electricity used in the plating process?
The electric current is used to dissolve metal and deposit it into a surface.
II. Video 2: Producing a Can https://www.youtube.com/watch?v=THhxEZhsMnw
1. How many cans can be produced by this factory in one
day? More than one and a half million cans per day.
2. How is the metal for the can shipped to the factory?
Its shipped in large metal sheets
3. How is the can shaped?
First its cut into smaller pieces and bent around a cylinder
tube
4. Why is beading applied to the can?
To strengthen the can
III. Video 3: Packing the Can
https://www.youtube.com/watch?v=vaKgs4BKajs
1. How are the sardines processed?
First they wash the fish the scales are removed then the heads and tails are cut off then
placed in the can then cooked.
2. When are the sardines cooked?
The sardines are cooked while in the can.
3. What types of fillings are also included in the
cans?
Oil or specific flavor of tomato sauce
4. Why are the cans pressure-sealed?
So when they exit the machine the sardines are air
tight because it goes into another machine to
sterilize it to keep it fresh.
1. What physical and chemical
properties would be important in the
steel base of the can?
2. What physical and chemical
properties would be important in the
tin that plates the outside of the can?