Question

1. What is the role of depressant in froth floatation process?

2. Explain with an example.

Answer 1

1. Depressants prevent certain type of particles from forming froth during froth floatation process.

2. NaCN acts as a depressant for ZnS but not for PbS. Thus, when an ore containing PbS and ZnS is subjected to froth floatation process NaCN selectively prevents ZnS from coming to the froth but allows PbS to come with the froth. In this way, PbS can be separated from ZnS.