2） Novel reagent to replace dithiophosphate/3418A for galena and chalcopyrite flotation

　　Novel reagent to replace dithiophosphate/3418A for galena and chalcopyrite flotation
　　Innovative environment benign reagent for galena and chalcopyrite flotation.

　　INTRODUCTION
　　Currently China has around 800 lead-zinc mines, at the end of 2015, China has lead and zinc retained reserves of 35.72 million tons and 93.84 million tons, respectively, ranking third in the world. However, each year China needs to import huge amount of lead, zinc concentrate, lead and zinc concentrate external dependence has reached 35% and 20% in 2015, which shows that China is in short of lead and zinc resources.

　　While there are some shortcomings regarding the flotation of galena by conventional process under higher alkalinity, such as higher consumption of water and electricity, environmental pollution caused by waste water and tailings from mineral processing, as well as lower recovery of associated Ag/Au.

　　The current innovative environment benign reagent and process is being applied in one Chinese state-owned mining company (Shuikoushan). Which is located at Songbai town, 40 km south to Hengyang City, Hunan province, PR China, is a large state-owned enterprises including non-ferrous metal mining, ore dressing, smelting, processing and trade. The company joined the Hunan Nonferrous Metals Holding Group Co, Ltd. in 2004，and joined the China Minmetals Corporation in 2009.

　　DEVELOPMENT
　　Numerous kinds of reagents have been tested either in laboratory or pilot scale test in the plant, which includes dithiophosphate and 3418A. Actually dithiophosphate has been applied in this plant more than ten years, while it has some disadvantages as followed:

　　(1)    Bad operating condition due to the toxic smell of reagent;
　　(2)    Annual penalty to surrounding community due to the toxic smell;
　　(3)    Lower recovery of associated Ag/Au;
　　The process flowsheet and reagent have been optimized to minimize the operating cost while maintaining acceptable quality of galena concentrate and improved recovery of Ag/Au with the following features:

　　(1)    Environment benign, no penalty to community any more;
　　(2)    Significantly improve the recovery of associated Au/Ag;
　　(3)    Half price of 3418A with similar dosage and better metallurgical performance;
　　(4)    Additional 3 million USD per year revenue for a plant (1500t/d).

　　RELEVANCE
　　The Shuikoushan project is a good recent example to develop environment benign reagents in Huaqi to meet the increasing demand of clients, as more strict environmental regulation is put forward by Chinese government, this innovative novel reagent could be good reference for other mining plants for the processing of galena and chalcopyrite around the world.