Alternative methods of extracting metals/metals in general

why is alternative methods of extracting metals needed

ores like copper are becoming scarce so new mining methods like Phyto mining and bioleaching

Phytomining

uses plants to absorb metal compounds (often from the waste from previous mining). The plants are harvested and then burned to produce ash that contains metal compounds. These metal compounds are separated from ash using chemicals or heated

bio leaching

uses bacteria to produce leachate solutions that contain (dissolved) metal compounds. The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis.

What type of ores can phytomining and bioleaching be used on?

low grade ores

explain the steps of bio leaching

1) A solution is made containing the copper ore and bacteria

2) The bacteria feed on the copper ore

3)The bacteria feeding on the ore produces pure copper

4)The pure copper is collected as a leachate(solutions)

Bioleaching uses bacteria to make leachate solutions that contain metal compounds, describe two ways the metals are extracted from these solutions.

-displacement using scrap iron

-electrolysis.

corrosion

is the destruction of materials by chemical reactions with substances in the environment.

rusting

-example of corrosion

- needs both air and water to take place

-iron + water + oxygen 🡪 hydrated iron (III) oxide

how can corrosion be prevented

applying coating that acts like a barrier to the metal(e.g. greasing, painting or electropainting)

Galvanizing: Some of these coatings are reactive and contain a more reactive metals to provide sacrificial protection, e.g. zinc is used to galvanize iron.

what does aluminum have that stops full corrosion

has an aluminum oxide coating that protects the metal from further corrosion .oxygen and water cannot penetrate

-aluminum have a low density

what are steels

alloys of iron that contain specific amounts of carbon and other

metals.

High carbon steels-strong but brittle

Low carbon steel is softer and more easily shaped.

Stainless steels- containing chromium and nickel are hard and resistant to corrosion.

Extracting copper from copper-rich ores

-copper is a finite resource

-quickly running out

-methods use to extract are expensive, energy-intensive

and polluting the environment

what do both pythomining bioleaching do?

Both methods produce a solution of metal compounds - more concentrated than they were in

the low-grade ore

1st stage of extracting copper from malacite(Thermal decomposition)

-heat the malacite in a boiling tube

observations-green powder(malacite) turned black and bubbles of gas were relieved

copper carbonate --> copper oxide

(malacite) (black)

CuCO₃ --> CuO+ CO2

2nd stage of extracting copper from malacite( add sulphric acid)

-add dullute sulphuric acid to copper oxide

observations-black powder added ,colourless solution become blue solution

copper oxide + slphuric acid --> copper sulphate + water

(black powder)+(colourless solution)-->(copper sulphate) +(colourless)

CuO + H₂SO₄ --> CuSO₄ + H₂O

3rd stage of extracting copper from malacite (Extracting the copper)

-put a clean iron nail in the copper

observations-gray iron nail goes red/brown in the blue solution

copper sulphate + iron --> iron sulphate + copper

CuSO₄ + Fe --> FeSO₄ + Cu

Two methods of extracting copper (currently)

Smelting(used for high grade ores)

Sulfuric acid(used for low grade ores)

smelting

his involves heating the copper ore up to very

high temperatures which produces impure copper. This is

then used in the process of electrolysis to extract the

pure copper metal.

sulfuric acid

used to make copper sulphate solution,

which is then used in electrolysis to extract the copper

metal.

electrolysis

The decomposition (breakdown) of a compound using an electric current.

What happens to iron(III) ions in Fe₂O₃ during extraction?

Fe³⁺ ions are reduced to Fe (gain electrons).
Ionic Eq: Fe₂O₃ + 3CO → 2Fe + 3CO₂
CO is oxidised to CO₂.

What happens when zinc is added to copper sulfate?

Zn displaces Cu, Zn is oxidised, Cu²⁺ is reduced.
Ionic Eq: Zn + Cu²⁺ → Zn²⁺ + Cu

what are the advantages of biological methods of metal extraction

• ✅ Eco-friendly – Less pollution, less habitat destruction

• ✅ Low energy – No high temperatures needed

• ✅ Reduces landfill waste – Useful for recycling metals from waste

what are the disadvantages of biological methods of metal extraction

• ❌ Slow extraction rates – Takes longer compared to traditional methods

• ❌ Limited to certain metals – Not all metals are economically viable for extraction using these methods.

• ❌ Low yield – Produces less metal