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Mercury Extraction from Cinnabar
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Mercury Extraction from Cinnabar
Mercury Extraction from Cinnabar
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1
Question
What is the first step in the extraction of mercury from cinnabar?
Answer
Crushing and pulverization to produce powdered ore.
2
Question
What device is used to crush big lumps of cinnabar ore?
Answer
Jaw crusher.
3
Question
What processes pulverize the crushed cinnabar ore into powder?
Answer
Pulverizer or stamp mill.
4
Question
What is the purpose of crushing and pulverization in mercury extraction?
Answer
To convert big lumps into powdered ore for subsequent processing.
5
Question
What is the second step after crushing in mercury extraction from cinnabar?
Answer
Concentration by froth flotation.
6
Question
What reagents are mixed with powdered cinnabar ore in froth flotation?
Answer
Water and pine oil.
7
Question
How are impurities separated from ore during froth flotation concentration?
Answer
Air is blown; impurities wetted by water sink, while ore wetted by oil rises as froth.
8
Question
What happens to the froth formed in cinnabar froth flotation?
Answer
It is skimmed off to obtain concentrated ore.
9
Question
What is the purpose of froth flotation in mercury extraction?
Answer
To concentrate the powdered ore by separating it from impurities.
10
Question
What step follows concentration by froth flotation in mercury extraction?
Answer
Roasting and distillation in a shaft furnace.
11
Question
What furnace is used for roasting and distillation of concentrated cinnabar ore?
Answer
Shaft furnace.
12
Question
What comprises the charge fed into the shaft furnace for mercury extraction?
Answer
Ore, coke, and lime.
13
Question
How is the charge introduced into the shaft furnace?
Answer
Fed via cup-and-cone arrangement.
14
Question
What are the heating conditions during roasting in the shaft furnace?
Answer
Heated red hot with air.
15
Question
What is the first chemical reaction during roasting of HgS in the shaft furnace?
Answer
\(2\text{HgS} + 3\text{O}_2 \rightarrow 2\text{HgO} + 2\text{SO}_2\).
16
Question
What is the second reaction following HgO formation in mercury extraction roasting?
Answer
\(2\text{HgO} \rightarrow 2\text{Hg} \text{(vapour)} + \text{O}_2\).
17
Question
Which process step corresponds to the oxidation reaction \(2\text{HgS} + 3\text{O}_2 \rightarrow 2\text{HgO} + 2\text{SO}_2\)?
Answer
Roasting of HgS in the shaft furnace.
18
Question
Which reaction produces mercury vapor during mercury extraction from cinnabar?
Answer
\(2\text{HgO} \rightarrow 2\text{Hg} \text{(vapour)} + \text{O}_2\).
19
Question
How is mercury vapor from roasting condensed into liquid mercury?
Answer
Condensed in water-cooled Y-shaped tubes.
20
Question
What is the final step after roasting and distillation in mercury extraction?
Answer
Purification of the crude mercury.
21
Question
What is the first method used in purifying crude mercury?
Answer
Filtration through chamois leather.
22
Question
What impurities does filtration through chamois leather remove from crude mercury?
Answer
Suspended oxides.
23
Question
What is the second purification step for crude mercury after filtration?
Answer
Treatment with 5% nitric acid.
24
Question
What does treatment with 5% nitric acid accomplish in mercury purification?
Answer
Removes impurities by forming metal nitrates.
25
Question
What is the final purification method for mercury after acid treatment?
Answer
Vacuum distillation.
26
Question
Which impurities are removed by vacuum distillation in mercury purification?
Answer
Silver, gold, and others; mercury distils leaving them behind.
27
Question
Which purification step specifically targets suspended oxides in crude mercury?
Answer
Filtration through chamois leather.
28
Question
In what order are the main steps for extracting mercury from cinnabar performed?
Answer
1. Crushing and pulverization; 2. Froth flotation concentration; 3. Roasting and distillation; 4. Purification.
29
Question
Why does ore rise as froth while impurities sink in cinnabar froth flotation?
Answer
Ore is wetted by pine oil and rises; impurities are wetted by water and sink.
30
Question
What role does air play when blown during froth flotation of cinnabar?
Answer
It creates bubbles that carry the oil-wetted ore to the surface as froth.