December 21, 2011   Demand for sulphate additives strengthens in China    An eFeedLink Exclusive     Prices were mostly stable.   Transacted prices of sulphate feed additives in China Variety Price as of Dec 6 (RMB/tonne) Price as of Dec 19 (RMB/tonne) Price change (RMB/tonne) Cupric sulphate 16,100-16,400 16,100-16,40 ...