Question

Froth flotation process used for the concentration of sulphide or sulfide ore is
__________________________________.
A.Is based on the difference in wettability of different minerals
B.uses sodium ethyl xanthate, ${C_2}{H_5}OC{S_2}Na$ as collector
C.uses $NaCN$ as depressant in the mixture of $ZnS$ and $PbS$ when $ZnS$ forms soluble complex and $PbS$ forms froth
D.all of the above statements are correct

Answer 1

It is a process for separating selective hydrophobic materials from hydrophilic materials. Also, sodium ethyl xanthate is a good absorber. Depressant is necessary to separate two sulphide ores.

Complete step by step answer:
Since, we know sulphide or sulfide ores are mostly concentrated by the froth-flotation process. The reason is pine oil selectively wets the sulphide or sulfide ore causing froth to form. So, first option is correct
Now, there must be something to absorb as well and sodium ethyl xanthate, ${C_2}{H_5}OC{S_2}Na$ is a very good absorber. So, I can act as a collector. Second option is also correct.
As we know there are multiple ore compositions present in the initial mixture so, in order to prevent the mixing of froth ores depressants are used, and $NaCN$ as depressant in the mixture of $ZnS$and $PbS$ when $ZnS$ forms soluble complex and $PbS$ forms froth, and prevents $ZnS$ from mixing into it. This happens because a complex reaction is involved in it. In which, $ZnS$ forms a complex with $NaCN$ .
$4NaCN + ZnS \to N{a_2}\left[ {Zn{{(CN)}_4}} \right] + N{a_2}S$
So, third option is also correct and hence, the (D) option all of the above is correct.

Note:
Froth flotation which is a concept of surface chemistry is very much used in recovery and enriching the sulfide ore. This process is used in various industries like Mineral Processing, Water treatment, paper recycling etc.