The method used to extract metals from the ore in which they are found depends on their reactivity. For example, reactive metals such as aluminium are extracted by electrolysis, while a less-reactive metal such as iron may be extracted by reduction with carbon or carbon monoxide.
Similarly, you may ask, why is carbon used in the extraction of Aluminium?
Aluminium is too high in the electrochemical series (reactivity series) to extract it from its ore using carbon reduction. The temperatures needed are too high to be economic. Instead, it is extracted by electrolysis. The aluminium oxide has too high a melting point to electrolyse on its own.
Why does the anode need to be replaced?
During the electrolysis process, aluminium is deposited at the cathode and oxygen is liberated at the anode. Some of this oxygen reacts with the carbon in the graphite to form carbon-dioxide, thus slowly burning away the anodes. Thus, the anodes have to replaced periodically.
Why are carbon anodes replaced regularly in the industrial electrolysis of Aluminium oxide?
The use of cryolite reduces some of the energy costs involved in extracting aluminium. The diagram shows an aluminium oxide electrolysis tank. Both the negative electrode (cathode) and positive electrode (anode) are made of graphite, a form of carbon. As a result, the positive electrodes have to be replaced frequently.
Why is the extraction of Aluminium an expensive process?
Aluminium oxide has a very high melting point (over 2,000°C), so it would be expensive to melt it. Instead, it is dissolved in molten cryolite, an aluminium compound with a lower melting point than aluminium oxide. The use of cryolite reduces some of the energy costs involved in extracting aluminium.
Why aluminum does not corrode like iron?
Unlike iron and steel, aluminium does not rust or corrode in moist conditions. Its surface is protected by a natural layer of aluminium oxide. This prevents the metal below from coming into contact with air and oxygen.
Why does aluminum conduct electricity?
For example, copper is used for electrical wiring because it is a good conductor of electricity. Metal particles are held together by strong metallic bonds, which is why they have high melting and boiling points. The free electrons in metals can move through the metal, allowing metals to conduct electricity.
How is Aluminium used?
Aluminium is a silvery-white, lightweight metal. It is soft and malleable. Aluminium is used in a huge variety of products including cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts. This is because of its particular properties.
Why do aluminum ions move to the negative electrode?
Metal ions are positively charged, so metals are produced at the negative electrode (cathode). Negatively charged ions move to the positive electrode. Non-metal ions, such as oxide ions and chloride ions, are negatively charged, so gases such as oxygen or chlorine are produced at the positive electrode (anode).
Why gold is so expensive?
Gold is relatively rare in the earth’s crust, and particularly because of its value in making jewelry, it has always been worth a lot of money. Aluminum is very common, and is nowadays, easily formed as the pure metal, so it is not very cheap.
Why do we need to recycle aluminum?
Recycling. Aluminium is extensively recycled because less energy is needed to produce recycled aluminium than to extract aluminium from its ore. Recycling preserves limited resources and requires less energy, so it causes less damage to the environment.
How Aluminum is recycled?
The consumer throws aluminium cans and foil into a recycle bin. It then goes through a re-melt process and turns into molten aluminium, this removes the coatings and inks that may be present on the aluminium. The aluminium is then made into large blocks called ingots. Each ingot contains about 1.6 million drinks cans.
What metal is often extracted and purified from its ore using both smelting and electrolysis?
Copper can be extracted from its ore by heating it with carbon. Impure copper is purified by electrolysis in which the anode is impure copper, the cathode is pure copper and the electrolyte is copper sulphate solution. An alloy is a mixture of two elements, one of which is a metal.
What can be done to conserve natural resources of Aluminium?
Aluminium Recycling – Sustainability. Aluminium recycling benefits present and future generations by conserving energy and other natural resources. It requires up to 95% less energy to recycle aluminium than to produce primary metal and thereby avoids corresponding emissions, including greenhouse gases.
Why is aluminum ductile?
The metallic bond is the force of attraction between these free electrons and metal ions. Metals are good conductors of electricity and heat, because the free electrons carry a charge or heat energy through the metal. The free electrons allow metal atoms to slide over each other, so metals are malleable and ductile.
What are the properties of aluminum?
Aluminium – Advantages and Properties of Aluminium
Topics Covered. Background.
Background. Physically, chemically and mechanically aluminium is a metal like steel, brass, copper, zinc, lead or titanium.
Electrical and Thermal Conductivity.
Impermeable and Odourless.
How do we make Aluminium?
The aluminium is extracted from bauxite by electrolysis. The aluminium oxide is melted and electrolysed. The anode is made of graphite, a form of carbon. Oxygen ions move to the anode where they’re converted to oxygen.
What metals can be extracted by carbon?
Metals such as zinc, iron and copper are present in ores as their oxides. Each of these oxides is heated with carbon to obtain the metal. The metal oxide loses oxygen, and is therefore reduced. The carbon gains oxygen, and is therefore oxidised.
How do we mine aluminum?
Aluminium (Al) comprises about 8.2% of the Earth’s crust. It is the third most abundant element in the crust and the most plentiful metallic element, but is never found on its own in nature. Bauxite is the ore most commonly mined for aluminium in which aluminium occurs as hydroxide minerals.
Where does the aluminum come from?
To make aluminium the ore (bauxite) must first be mined. The main sources of bauxite are in Australia, South America and Africa, but other countries including China, Jamaica, India and USA also have large amounts of the ore.
Where is aluminum found?
History and Uses: Although aluminum is the most abundant metal in the earth’s crust, it is never found free in nature. All of the earth’s aluminum has combined with other elements to form compounds. Two of the most common compounds are alum, such as potassium aluminum sulfate (KAl(SO4)
How Aluminum was first discovered?
Aluminium was named after alum, which is called ‘alumen’ in Latin. This name was given by Humphry Davy, an English chemist, who, in 1808, discovered that aluminium could be produced by electrolytic reduction from alumina (aluminium oxide), but did not manage to prove the theory in practice.
How do you extract iron from its ore?
Iron is extracted from iron ore in a huge container called a blast furnace. Iron ores such as haematite contain iron oxide. The oxygen must be removed from the iron oxide to leave the iron behind. Reactions in which oxygen is removed are called reduction reactions.
What is used in Phytomining?
Some plants absorb copper compounds through their roots. They concentrate these compounds as a result of this. The plants can be burned to produce an ash that contains the copper compounds. This method of extraction is called phytomining. Some bacteria absorb copper compounds.