With reference to 'fly ash' produced by the power plants using coal as

With reference to ‘fly ash’ produced by the power plants using coal as fuel, which of the following statements is/are correct?

1. Fly ash can be used in the production of bricks for building construction.
2. Fly ash can be used as a replacement for some of the Portland cement contents of concrete.
3. Fly ash is made up of silicon dioxide and calcium oxide only, and does not contain any toxic elements.

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1 and 2

2 only

1 and 3

3 only

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC IAS – 2015

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Statements 1 and 2 are correct regarding the uses of fly ash produced by power plants. Statement 3 is incorrect as fly ash contains more than just silicon dioxide and calcium oxide, and it can contain toxic elements.

Fly ash is a valuable by-product with established applications in construction materials. It is commonly used in manufacturing bricks and as a partial replacement for Portland cement in concrete mixes, improving properties like strength and durability. However, fly ash contains various metal oxides and trace elements, some of which can be toxic.

Fly ash typically consists primarily of silicon dioxide (SiO₂), aluminium oxide (Al₂O₃), iron oxide (Fe₂O₃), and calcium oxide (CaO). It also contains smaller amounts of magnesium oxide (MgO), titanium dioxide (TiO₂), sulphur trioxide (SO₃), and trace amounts of other elements, including heavy metals like arsenic, mercury, and lead, depending on the source of coal and combustion conditions. Its utilization helps in waste management and environmental protection by reducing the need for conventional materials and preventing landfilling.

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