1, according to the query, the composition is different: the main component of copper alloy is copper, and different kinds of copper alloys are made by adding different alloying elements. ; Placer gold is a yellow precious metal alloy containing silver, the main components of which are silver, copper and zinc, and the silver content exceeds 80%.

2. Different properties: Copper alloys are widely used in industrial products, pipelines, wires and cables. Placer gold is suitable for jewelry, gold bars, gold coins and other products.