Microwave carrier roasting enhancement of gold leaching from high-silica fine particulate refractory ores

A certain gold ore from northern Longnan, Gansu Province, is a typical high-silica fine particulate refractory ore. Using a direct cyanide leaching process, the gold leaching rate is only 52.14 %. To further improve the gold leaching rate, magnetite was introduced as a microwave roasting carrier medium, and research on the microwave carrier roasting−cyanide leaching process was conducted. After pretreatment with microwave carrier roasting, the gold leaching rate increased to 75.04 %, representing an improvement of 22.90 percentage points compared to the conventional whole-ore cyanide leaching process. Subsequently, the magnetite in the cyanidation tailings was recovered using a magnetic sorting process, achieving a recovery rate of 89.34 %, which allows for the recycling of the carrier medium. This process not only enhances the gold leaching rate but also reduces the use of traditional energy sources such as coal or natural gas, contributing to the green and efficient recovery and smelting of gold ores.