Question

2) Sulfide ore mining can cause various environmental problems. List the potential problems associated with sulfide ore mining. Write down a couple of simplified chemical reactions to explain the origins of the problems. What are the common techniques to minimize these negative environmental impacts? Give some brief explanations.

Answer 1

1) The problems associated with sulphide ore mining are as follows

i) during mining of sulphide ore, it exposed to water and air, the chemical reaction takes place it forms sulphuric acid which leads to to acid rain.

ii) pollute nearby sources of water

iii) physical disturbances to landscape

iv) problem to public safety

2) The chemical reaction which explains the origin of problem is as

- during extraction of metal from pyrite ore sulphur dioxide gas is liberated which futher oxidises and hydrolyzes to form sulfuric acid

Eg. Extraction of of copper from copper pyrite ore

2CuFeS2 + O2 ---> Cu2S + 2Fes + SO2 Roasting Reaction

SO2 + 1/2O2 -----> SO3

SO3 + H2O ----> H2SO4

3) The common techniques to minimise negative impacts on environment are as follows

I) Proper water disposal:- The proper water disposal is very important to minimise the negative environmental impacts. The sulphur dioxide gas is disposed in plenty of water, so as it gets diluted and does not produce harmful effect on environment.

II) Improving manufacturing processes:- The improving efficiency of manufacturing or metallurgical processes can help to reduce adverse effect on environment. The alternative metallurgical processes should be developed so that there is no formation of harmful chemicals like sulphuric acid, sulphur dioxide etc.