Explain the role of the following :
(a) NaCN in froth floatation process.
(b) I2 in the metallurgy of Zr.
(c) Limestone in the metallurgy of Fe.
(a) NaCN selectively prevents one of the sulphide ore from coming to the froth.
(b) I2 in the metallurgy of Zr, Helps in converting Zr into its volatile compound ZrI4.
(c) Limestone in the metallurgy of Fe, Provides flux to remove impurities.