If restated, the sentence that would best replace `As a conductor of the heat and electricity, aluminium exceeds all  metals except silver and gold.`

Sliver and gold are exceeded only by Aluminium as conductors of heat and electricity.

With the exception of aluminum, silver and gold are better than any other metal as conductors of heat and electricity.

Silver and gold are better conductors of heat and electricity than aluniminum is

Aluminium is better conductor of heat and electricity than silver and gold.