How can the prices for base metals be different at Exchanges

#1
How the prices vary between LME and SHFE..? What is to stop someone from purchasing physical aluminium from the cheaper exchange and then selling it at the higher priced one.
 

Broker Special Offers

Intraday Higher Leverage

Save up to 90% in brokerage and get higher leverage for intraday trades.

Name:Phone:
Email:City:
State:
Are you a day trader?