NaCN is sometimes added in the froth flotation process as a... | CHEMISTRY - CONCENTRATION OF ORES | SolveeIt | Solveeit

Today, August 24

Question

NaCN is sometimes added in the froth flotation process as a depressant when ZnS and PbS minerals are expected because

A

Pb(CN)2 is precipitated while no effect on ZnS.

B

ZnS forms soluble complex Na2[Zn(CN)4] while PbS forms froth

C

PbS forms soluble complex Na2[Pb(CN)4] while ZnS forms froth.

D

NaCN is never added in froth floatation process.

Answer

ZnS forms soluble complex Na2 $Zn(CN)4$ while PbS forms froth

Explanation

Solution

ZnS + 4NaCN ® Na2[Zn(CN)4] + Na2S

PbS + NaCN ® No such complex formation.