Question

Find out D from the given flowchart :

• A. pig iron
• B. FeO
• C. blister Cu
• D. wrougbt iron

Answer 1

The correct option is C blister Cu

It can be seen that D is Blister copper.

Process:

Copper pyrites contain only 2-3% of copper. The rest of the ore contains iron as sulphide, silica, silicious materials, sulphur, arsenic etc as impurities. Froth floatation is carried out by xanthate and pine oil. The froth is collected and dried when concentrated ore is obtained which contains 25-30% of Cu. Then smelting of the roasted ore in blast furnace is done. The minor reactions that occurred during roasting continue here. Ferrous oxide combines with sand to form a fusible slag. Cuprous oxide formed combines with ferrous sulphide to give ferrous oxide and cuprous sulphide. This is because iron has more affinity for oxygen than copper.

$FeO+Si{O}_2\to FeSi{O}_3$

$C{u}_{2}O+FeS\to C{u}_{2}S+FeO$

When molten copper cools, it gives off disolved $S{O}_2$. The $S{O}_2$ gas escaping in the form of bubbles leaves the surface of the metal forming cavities which gives the metal a blistered appearance. This is why the metal thus obtained is called blister copper (D).

Then finally by electrolysis we get pure copper.