Which of the following is used to prepare the inner lining of a blast furnace?

The reducing agent which is used to reduce iron oxide in blast furnace is

During the extraction of gold the following reactions take place

$$\mathrm{Au + C{N^ - } + {H_2}O\buildrel {{O_2}} \over \longrightarrow [X]}$$

$$\mathrm{[X] + Zn\buildrel {} \over \longrightarrow [Y] + Au}$$

X and Y are respectively

Ellingham diagram represents a graph of