The pre-treatment of them before conventional cyanide leaching includes roast, chemical oxidation and biological oxidation.
在传统氰化浸出之前进行的预处理过程包括焙烧，化学氧化和生物氧化。
2
The finish of the hand is achieved by electroplating involving several stages: leaching, degreasing, pre-nickelplating and nickelplating, along with numerous rinses.
指针的表面电镀需经过下列几道工序：过滤、去油脂、预镀镍、镀镍，之间还穿插了数次清洗。
3
In this paper the application and recent developments of heap leaching technology abroad are pre sented, and the main technological and economic performances of heap leaching operations are listed.