Market asssessment: design and synthesis of well-defined ligands for selective extraction of precious metals (with initial emphasis on gold)

我们正在开发的技术涉及设计用于从碱性氰化物溶液中选择性提取金的新型配体。氰化工艺是从矿石中提取和回收金的主要技术。目前的技术包括使用大量活性炭从溶液中提取金作为二氰酸盐(I)。然后通过进一步添加碱性氰化钠溶液将二氰酸盐(I)络合物从活性炭中除去，然后通过电积还原为单质金。在提取步骤中使用大量氰化钠仍然极具争议，并引起了很大的环境问题。活性炭工艺也是整个提取过程中最昂贵的一步。我们将通过使用对二氰酸酯(I)具有高度选择性的配体来完全消除这一过程，然后通过建立的溶剂萃取技术来去除所得到的配合物。然后，配体将被回收用于额外的提取。目前还没有一种溶剂萃取系统在黄金工业化生产中得到成功的应用。

The technology we that we are developing involves the design of novel ligands for selective extraction of gold from alkaline cyanide solutions. The cyanidation process is the dominant technique for extraction and recovery of gold from ore. Current technologies involve use of large amounts of activated carbon to extract the gold from solution as dicyanoaurate(I). The dicyanoaurate(I) complex is then removed from the activated carbon by further addition of a basic sodium cyanide solution and then reduced to elemental gold by electrowinning. The use of large amounts of sodium cyanide in the extraction step remains extremely controversial and is of great environmental concern. The activated carbon process is also the most expensive step in the whole extraction process. We will eliminate this process completely by using ligands that are highly selective for dicyanoaurate(I), following which the resulting complex can be removed by established solvent extraction technologies. The ligand would then be recycled for additional extractions. No solvent extraction system has ever been successfully implemented in the industrialization of gold production.