| 摘要 |
Manufacture of Peroxides Conventionally, gold and silver are obtained from their ores by agitation leaching the ore, after grinding, with an oxygen-containing aqueous alkaline cyanide solution. Problems that can be encountered in the leaching include long leaching times, maintenance of sufficient dissolved oxygen and high consumption of cyanide, which can result in slow or impaired extraction of precious metal. The addition of small amounts of poorly soluble inorganic peroxides and particularly calcium peroxide, such as from 0.1 to 20 parts w/w per 1000 parts of ore provides a convenient way to control and maintain suitable levels of dissolved oxygen and can result in one or more benefits of increased or more rapid extraction of the precious metal and reduction in cyanide consumption. The insoluble divalent metal peroxides can be produced at a controlled rate demanded by the leaching process by monitoring the dissolved oxygen level in and the pH of the leaching process, and using the monitored levels to control the rate of addition of hydrogen peroxide to divalent metal compound and the mole ratio of the two reagents. IX11 |
