Copper concentrate purchase, 15 000 mt, CIF China

I would like to purchase copper concentrate on a monthly basis.
Minimum concentration of copper - more than 25%. 
Minimum monthly quantity: 15000 mt.
Specification: authorized for P.R.C.
Origin: Asia. Africa, South America.
Destination port: Shanghai Port, China<.
Terms: CIF discharge port – FOB port.
Packaging: Standard Export Packing.
One year contract.
Please send your offers with the specifications and quotation.