Question:
Which of the following ore is concentrated using group 1 cyanide salt ?
Correct Option: 1
Solution:
Sphalerite ore : $\mathrm{ZnS}$
Calamine ore : $\mathrm{ZnCO}_{3}$
Siderite ore : $\mathrm{FeCO}_{3}$
Malachite ore : $\mathrm{Cu}(\mathrm{OH})_{2} . \mathrm{CuCO}_{3}$
It is possible to separate two sulphide ores by
adjusting proportion of oil to water or by using
'depressants'. In case of an ore containing ZnS
and $\mathrm{PbS}$, the depressant used is $\mathrm{NaCN}$.