C1.3 Flashcards
What is bioleaching?
~ Bacteria is used to grow on the low grade copper ore
~ Bacteria produce a solution as a by-product
~ The solution can then go through electrolysis or displacement to extract the metal
How does electrolysis work?
~ Two electrodes are added to a solution in the form of a salt
~ Positive ions are attracted to negative electrode
~ Negative ions are attracted to positive electrode
~ Metal can then be removed
What is displacement?
~ Scrap iron is put in a solution of a metal salt
~ Metal will coat itself around the outside of the scrap iron
~ Metal can then be extracted
What is the difference between low carbon steel and high carbon steel?
~ Low carbon steel is easy to shape
~ High carbon steel is hard and resistant to corrosion
What does steel and chromium produce?
Stainless steel
Why is stainless steel useful?
~ Doesn’t rust
~ Not very reactive
~ Not corrosive
Why are metals such as aluminium and gold turned into alloys with copper?
~ Makes them harder
~ Less expensive
What is an ore?
A type of rock containing a metal that’s economically worth extracting
Why are phytomining and bioleaching important?
They produce the pure metal from low grade ores
Give the symbol equation for a reduction reaction using carbon and a metal ore
2FeO + C -> 2Fe + CO2
What is Phytomining?
Where plants are absorbed to make metal compounds. Plants are then burned and the metal can be separated out from the ash produced
What metals can be extracted using reduction?
Those below carbon in the reactivity series
How is phytomining done?
~ By growing a certain type of plant on low grade copper ore
~ Some plants have the ability to take out the metal compounds from the ore and take it into their body tissue
~ The plants are then taken and burnt
~ Ash remains contain the metal which can be extracted using electrolysis or displacement
What are some properties of titanium and aluminium?
~ Low density
~ Resistant to corrosion
What are some properties of copper?
~ Good conductor of heat and electricity
~ Malleable
~ Not reactive with water, so can be used in piping
What is an alloy?
A mixture of metals
Why is 100% pure metal not useful?
Too soft
What is wrong with impure iron?
~ Brittle
~ Strong so can’t get compressed
What is in the blast furnace?
~ Coke
~ Limestone
~ Iron oxide
Where is iron produced?
In a structure called the Blast Furnace
What is the first step to extracting metals?
Concentrating the ore, which removes some impurities and makes the ore have more metal inside
Why are there problems with extracting copper?
~ Carbon reacting with copper produces impure copper so electrolysis must be used to make it pure
~ Copper rich ores are running out, making it expensive
How are metals above carbon in the reactivity series extracted?
~ The ore is melted
~ Electricity is used to separate the metal and oxygen
Why is no reaction required to remove oxygen from gold?
It’s so unreactive that it’s not found as an oxide, and can be found native in the ground
How can a metal which is below carbon in the reactivity series be extracted?
It’s reacted with carbon because the carbon takes the oxygen from the metal
How can low grade ore be extracted?
Phytomining / bioleaching
How can high grade ores be extracted?
Smelting, then electrolysis / displacement
What are the properties of transition metals?
~ Good conductors of heat and electricity
~ Malleable
Why are gold, aluminium and copper not useful alone, and how can they be made more useful?
~ They’re too soft
~ They can be mixed with other metals to make them harder
What is a use of titanium?
To make hip joints
What are some uses of aluminium?
~ Aeroplane bodies
~ Power lines
What are some uses of copper?
~ Cooking pots and pans
~ Piping
Why should we recycle metals?
~ To save money and energy
~ To ensure all natural resources don’t get used up
~ To reduce the amount of mining which damages the environment
