Question

Which of the following ore is concentrated using group 1 cyanide salt?

Options

• Sphalerite

• Siderite

• Malachite

• Calamine

Answer 1

Sphalerite

Explanation:

• Sphalerite Zinc blende/Sphalerite: ZnS
• Malachite: CuCO₃, Cu(OH)₂
• Calamine: ZnCO₃
• Siderite: FeCO₃

Cone. of sphalerite, first by cyanide salt as a depressant to remove the impurity of Galena.

\[\ce{ZnS + PbS + \underset{excess}{NaCN} -> \underset{solution}{Na2[Zn(CN)4]} + PbS ↓}\]