How can a reaction with positive ΔG be made to occur?

What is the criterion of the feasibility of a reaction at any temperature?

Which of the following is not refined by zone refining method?

In the metallurgy of aluminium, purified bauxite is mixed with Na2AlF6.

Zone refining is also called fractional crystallization.

What is the property of necessary for an ore to be concentrated by electrostatic separation?

Copper is extracted from low grade copper ores.

What is the role of the rotating paddle in froth floatation?