Statement-1: In extraction of copper from chalcopyrite after roasting in supply of air at moderate temperature, the temperature of the roasting ore is increased above the fusion temperature and then silica is added in reverberatory furnace.

Statement-2: In the extraction of copper from chalcopyrites during smelting, the impurity of iron oxide is removed as fusible slag (${\mathrm{FeSiO}}_3$) in blast furnace or reverberatory furnace.

Both the given statement is incorrect. The correct statements are as follows,

During roasting, the sulphide that is already present is changed into oxide and emitted as sulphur dioxide, a gas. Roasting's primary purpose is the removal of volatile impurities and the oxidation of the ore, which results in oxide.

Iron is the primary contaminant found in copper ores. Slag is produced when silica and iron react. The slag produced in the blast furnace is therefore${\mathrm{FeSiO}}_3$  .

The following is the reaction that occurs in the blast furnace:

$\mathrm{FeO}+{\mathrm{SiO}}_2\to {\mathrm{FeSiO}}_3\text{ (slag) }$

Hence, option D is correct.