贵金属经常以不同类型矿脉矿化,有时与硫化矿物共生.大量试验证明,不同形式矿化的许多贵金属矿石均可有效地预先富集。在很多情况下,可以使用光度拣选、导电拣选、放射性拣选,以及这些方法的联合流程预选。过去,除南非使用放射性拣选外,很少有人考虑这些方案。本文报道北美现在制定的主要拣选方案及其技术和经济特征. Precious metals are often mineralized with different types of veins, sometimes coexisting with sulphide minerals, and numerous tests have demonstrated that many precious metal minerals of different mineralization types can be efficiently pre-enriched. In many cases, photometric sorting, conductive sorting, radioactive sorting, and the combined process preselection of these methods can be used. In the past, few options were considered outside South Africa except radioactive sorting. This article reports on the major picking options now in North America and their technical and economic characteristics.