C6.1.9 Biological Metal Extraction

Question 1

Bioleaching

Answer 1

Biological method of metal extraction in which bacteria speed up reactions that release soluble metal compounds from metal sulfides

Question 2

Carbon-neutral

Answer 2

Balance between emitting carbon + absorbing carbon

Question 3

Low-grade ores

Answer 3

Metals extracted from ores that contain too little metal for traditional methods to be profitable

Question 4

Phytoextraction

Answer 4

Biological method of metal extraction in which plants absorb metals through their roots + concentrate them in their cells

Question 5

High-grade ore

Answer 5

Rick with a high conc of metal

Question 6

Photo extraction

Answer 6

When is it used? For low grade ores
Materials require? Uses certain types of plant
Relative speed of process? Relatively slow
Relative cost of processes? Relatively cheap
Environmental effects - air pollution from burning plants + smelting to yield metal

Question 7

Bioleaching

Answer 7

When is it used? Low grade ores
Materials required? Uses certain type of bacteria
Relative speed of process? Relatively slow
Relative cost of process? Relatively cheap
Environmental effects - no air pollution but can produce toxic substances

Question 8

Stages of phytoextraction

Answer 8

• grows plants in soil containing low-grade copper ores
• burn the plants to produce an ash containing the copper compounds
• mix the ash with a reducing agent such as carbon + place in a suitable furnace
• smelt the mixture by heating to high temperatures so the copper is reduced and the dense molten metal sinks to bottom of furnace
• drain off the molten copper and allow to cook into ingots of pure metal