In the manufacture of steel,the Bessemer converter contains a lining of:

Identify $A$ and $B$ respectively in the following reactions:
$4 Au_{(s)} + 8 CN^{-}_{(aq)} + 2 H_2O_{(aq)} + O_{2(g)} \longrightarrow 4 A_{(aq)} + 4 OH^{-}_{(aq)}$
$2 A_{(aq)} + Zn_{(s)} \longrightarrow B_{(aq)} + 2 Au_{(s)}$

In the cyanide process involving extraction of silver,zinc is used industrially as an

Statement $(A)$ $Mg$ can reduce $Al_2O_3$ above $1350^{\circ} C$.
Statement $(B)$ $Al$ can reduce $MgO$ below $1350^{\circ} C$.
The correct answer is

Matte contains mainly

Matte is a mixture of .......... .