UPSC Prelims 2021 · Question 17 of 97

UPSC Prelims 2021 question on Copper Smelting Concerns

Why is there a concern about copper smelting plants?

1. They may release lethal quantities of carbon monoxide into environment.

2. The copper slag can cause the leaching of some heavy metals into environment.

3. They may release sulphur dioxide as a pollutant.

Select the correct answer using the code given below.

  1. 1 and 2 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer

Answer: B. 2 and 3 only

Verdict

Correct statements: 2 and 3 → Option (b).

Analysis

Smelting is a process of applying heat to ore to extract a base metal. Copper concentrates are fed through a flash smelting furnace with oxygen-enriched air; the concentrates are instantly oxidized, after which they melt and separate by their own reaction heat into copper matte (~65% grade) and slag consisting of iron oxide, silica and other compounds.

Extractive metallurgical and smelting processes can be highly polluting. Facilities that carry out metal and smelting processes are known to emit high quantities of air pollutants such as hydrogen fluoride, sulphur dioxide, oxides of nitrogen, offensive and noxious smoke fumes, vapours, gases and other toxins.

Statement by statement

Statement 1 — INCORRECT: Copper smelting does release some carbon monoxide, but the lethal-quantity concern is not its primary or distinguishing hazard — the more characteristic concerns are SO2, suspended particulates with heavy metals, and slag-borne heavy metal leaching.

Statement 2 — CORRECT: Copper slag can have heavy metals like cobalt, zinc, arsenic, lead, cadmium, barium etc. Under natural weathering conditions slag can release these elements into soils, surface waters and groundwater.

Statement 3 — CORRECT: Sulphur dioxide is a major air pollutant released by copper smelting plants.

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