A plant in Wollongong is treating $70$ metric tonnes of ore having $12\frac{g}{T}$ of gold and $220\frac{g}{T}$ of silver

in each batch. The solid tailings contained $0\mathrm{.}6\frac{g}{\frac{?}{?}}$TAu and $35\frac{g}{T}Ag$ after the leaching processes, and

it is discarded after washing. The charge that enters the precipitation tank contains $300T$ solution.

The precipitation is $100\%$ complete. The total reagent used is $55k\frac{g}{c}$hargeKCN and $40k\frac{g}{c}$harge

Zinc.

Elsner Equation:

$2Au+4KCN+O+H2O=2$KAu$(CN)2+2$KOH Equation $1Or$

$4Au+8CN+O2+2H2O=4Au(CN)2+4OH-Equatio{n}_2$

Precipitation Equation:

KAu$(CN)2+2KCN+Zn+H2O=Au+K2Zn(CN)4+2H++$KOH

For Equations $1$ and $2$ above, $Au$ and $KCN$ are interchangeable with $Ag$ and NaCN.

Given

At$.$ wt$.$ of $Au=196\mathrm{.}9,K=39,Zn=65\mathrm{.}39,Ag=107\mathrm{.}9,C=12$ and

$N=14\frac{g}{m}ol$

$($j$).$ Calculate the efficiency of leaching for $Au$ and $Ag.$

$($ii$).$ The grade of solution entering the precipitation tank.

$($iii$).$ Percentage of KCN used in the actual dissolution of gold.

$($iv$).$ Percentage of Zn used in the actual precipitation of gold.