Recycling Aluminum
RECYCLING ALUMINUM
PURPOSE
To determine the mass of a hydrated aluminum potassium sulfate salt in a sample of impure scrap aluminum from a common beverage can. The sample will be passed through a filter paper using a funnel, after being boiled on a hot plate in a fume hood and dissolved in a solution of potassium hydroxide to remove the impurities. By adding an excess of sulfuric acid and cooling the solution in an ice bath, the technique of vacuum filtration using a Buchner funnel will be employed, crystals of the hydrated aluminum potassium sulfate salt will yield and these will be collected. Methanol will be used to rinse the crystals.
THEORY
Aluminum is the third most abundant element and is commonly used in packaging. In fact, 97% of all soft drink cans use this universal material. Recycling an aluminum can saves about 95% of the energy required to make a can out of virgin materials.
The preparation of aluminum begins with the reaction of aluminum (Al) and potassium hydroxide (KOH). The potassium hydroxide is used to dissolve some of the traces of various metals present in the sample of scrap aluminum and when reacting with the aluminum produces hydrogen gas and aluminate ions
2 Al(s) + 2 KOH(aq) + 6 H2O(l) 2 KAI(OH)4(aq) + 3 H2(g)
The limiting reagent in this reaction is aluminum since we are producing “alum” crystals. The excess reagent is KOH. This excess is necessary to help accelerate the reaction, therefore guaranteeing a maximum yield of crystals
Then, after sulfuric acid has been added, a number of reactions will occur:
The excess of potassium will be neutralized releasing heat,
2 KOH(aq) + H2SO4(aq) K2SO4(aq) + 2 H2O(l) and aluminate ions will react with the sulfuric acid to form the compound aluminum hydroxide
2 K+(aq) + 2 Al(OH)-4(aq) + H2SO4(aq) 2 K+(aq) + 2 Al(OH)3(s) + 2 H2O(l) + SO42-(aq)
Adding an excess of sulfuric acid will dissolve the aluminum hydroxide to produce Aluminum ions
2 Al(OH)3(s) +
PURPOSE
To determine the mass of a hydrated aluminum potassium sulfate salt in a sample of impure scrap aluminum from a common beverage can. The sample will be passed through a filter paper using a funnel, after being boiled on a hot plate in a fume hood and dissolved in a solution of potassium hydroxide to remove the impurities. By adding an excess of sulfuric acid and cooling the solution in an ice bath, the technique of vacuum filtration using a Buchner funnel will be employed, crystals of the hydrated aluminum potassium sulfate salt will yield and these will be collected. Methanol will be used to rinse the crystals.
THEORY
Aluminum is the third most abundant element and is commonly used in packaging. In fact, 97% of all soft drink cans use this universal material. Recycling an aluminum can saves about 95% of the energy required to make a can out of virgin materials.
The preparation of aluminum begins with the reaction of aluminum (Al) and potassium hydroxide (KOH). The potassium hydroxide is used to dissolve some of the traces of various metals present in the sample of scrap aluminum and when reacting with the aluminum produces hydrogen gas and aluminate ions
2 Al(s) + 2 KOH(aq) + 6 H2O(l) 2 KAI(OH)4(aq) + 3 H2(g)
The limiting reagent in this reaction is aluminum since we are producing “alum” crystals. The excess reagent is KOH. This excess is necessary to help accelerate the reaction, therefore guaranteeing a maximum yield of crystals
Then, after sulfuric acid has been added, a number of reactions will occur:
The excess of potassium will be neutralized releasing heat,
2 KOH(aq) + H2SO4(aq) K2SO4(aq) + 2 H2O(l) and aluminate ions will react with the sulfuric acid to form the compound aluminum hydroxide
2 K+(aq) + 2 Al(OH)-4(aq) + H2SO4(aq) 2 K+(aq) + 2 Al(OH)3(s) + 2 H2O(l) + SO42-(aq)
Adding an excess of sulfuric acid will dissolve the aluminum hydroxide to produce Aluminum ions
2 Al(OH)3(s) +
References: Chemistry 1110, Laboratory manual. Douglas College Chemistry Department. Fall 2009 Online pages: http://homeguides.sfgate.com/benefits-recycling-aluminium-79200.html http://www.studymode.com/essays/Gravimetric-Analysis-464879.html http://www.obu.edu/chemistry/files/2011/06/Recycling-Aluminum.pdf