Mhangura Mine copper ores have the metal in the minerals, bornite $(C{u}_{5}Fe{S}_4),$ chalcopyrite $(CuFe{S}_2)$ and chalcocite $(C{u}_2(S)).$ The gangue material is mainly, haematite $(F{e}_2{O}_3),$ silica $(Si{O}_2)$ and calcite $(CaC{O}_3).$ You are a metallurgist assigned to the rejuvenation of the mine processing plant. Shareholders suggest the current plant is deteriorated and will finance a fresh start up$.$

a$.$ Suggest two different process flow sheet routes for this type of ore. Include chemical reactions that would result in production of a sellable copper product. $[20]$

b$.$ Of the two, select one you would prefer and highlight its pros over the other. $[5]$

There is a drive to find substitutes to the use of mercury by small scale miners. Direct smelting of gravity concentrates is one of the most suggested ways to eliminate the use of environmentally unfriendly mercury amalgamation. Smelting energy costs and overall gold recovery are important in determining the adoption of this technology by small scale miners.

a$.$ Discuss ways that can be used to reduce the energy costs in the direct smelting of gold concentrates. $[6]$

b$.$ What are the desirable properties of slag that will result in increased recovery of gold? $[6]$

c$.$ Which additives can be used to remove impurities such as $Fe,Cu,Al$ and $Si$ from the gold dore? $[3]$

d$.$ What type of flux can be used in the smelting of gold concentrates? $[4]$

e$.$ State the role of the flux you suggested above $[6]$