The Recycling Factory

As we learn about properties of different substances in class, we have been given many scenarios about mixtures and have had to determine how to separate the individual substances of the mixtures.

Today, we have been given a scenario called "The Recycling Factory".

The question I am trying to answer is:
How do I separate a fine powder consisting of aluminum soda cans, steel cans, milk jugs, and soda bottles?

Aluminum soda cans

The densities of the materials are as followed:

• Aluminum soda cans- 2.7 g/cm^3
• Steel cans- 5.7 g/cm^3
• Milk jugs- 0.95 g/cm^3
• Soda bottles- 1.4 g/cm^3

 I have the following materials at my disposal:





Steel cans


•  large conveyor belt
• large tank that can be filled with water
• another large tank labeled "concentrated sugar water-, density = 1.5 g/cm^3"
• several powerful magnets hanging above the conveyor belt
• several nets for skimming the tanks and scooping material from the bottoms.

I will be writing a letter to the city official, Mr. Smith of Westminster, that describes my plan to separate the four recycled materials. If I do so and my plan works, I will be payed $5,000.

Here is my letter...

Milk jugs

 Mr. Smith:

 Thank you for presenting this recycling opportunity of business to the Owl Recycling Factory. The recycling and reusing of materials such as the ones that you have brought to our attention reduce pollution fo our environment every day. There is a slight problem, however, with the state in which your materials will be given to us. Owl Recycling Company must first separate different substances from one another before sending them out to be reused. Since the four materials in your dump truck are ground into a fine powder, the Owl Recycling Company will need to carry out a procedure other than what we normally would use to separate them. I would like to propose to you our plan to separate your recyclable powder mixture. Due to the materials being on your property, we need your OK on our plan before we can begin our recycling work.

Our plan is as follows:

1. Place the mixture in a container and send the container along a conveyor belt, above which several powerful magnets will be hanging. Since aluminum is magnetic, the fine pieces from the aluminum cans will be attracted to the magnets, and thus we will have that material separated from the mixture.
2. Next, we will pour what remains of the mixture in the container into a large tank full of water. Since anything with density less than that of water will float, we are positive that the fine pieces of milk jug will float. The density of water is 1 g/cm^3 and the density of milk jug plastic is g/cm^3. We will then place a net in the tank to scoop out the milk jug pieces afloat on top of the water (the rest of the mixture will be sunken on the bottom of the tank). After the milk jug peices are removed, we will use another net to filter out what had sunken to the bottom.
3. We will then put the remaining mixture into the tank labeled "concentrated sugar water, density= 1.5 g/cm^3". Since the density of soda bottles is 1.4 g/cm^3, the soda bottle pieces will float. We will use a net to fish out the soda bottle pieces afloat the top of the water.
4. Lastly, we will use a strainer to strain out the sugar water from the tank and the steel pieces will remain.

We hope that you will accept our plan for separating your recyclable materials. Thank you for doing business with us to help preserve our environment.


Sincerely,
Jane Doe
C.E.O., Owl Recycling Company

Soda bottles