Question

1.

Gold is concentrated from lower grade sources by the process of

smelting

roasting

refining

calcination

leaching

cyanidation

2.

Homogeneous mixtures in which the components are dispersed randomly and uniformly

interstitial alloy

substitutional alloy

solution alloy

ahoy there alloy

Answer 1

1. Smelting, roasting and calcination are metallurgical processes where an ore is heated to high temperatures in order to extract the base metal present in the ore. Leaching is the process where the ore is treated with chemicals to convert the metals present in the ore to their soluble salts. Cyanidation is specific to the extraction of gold and silver from their ores where the ores containing these valuable metals are dissolved in solutions of sodium or potassium cyanide to extract the metal. All the above processes involve chemical changes to the metal present in the ore.

Refining is the only process where a metal is made purer or more concentrated from the impure metal by various processes. The metal undergoes no chemical change during refining. Hence, the correct answer is refining.

2. The added components are dispersed randomly and uniformly; hence, the concentration of the components remains the same throughout the alloy. Such an alloy is a solution alloy.