Technology of Processing of Coal-Fired Electric Power-Plant Waste for Extraction of the Precious Metals

Technology of processing of coal-fired electric power-plants waste for extraction of the precious metals was developed by a group of scientists of the Far Eastern Federal University. Their method allows extracting gold, platinum and several types of construction materials out of the processed ashes. Adaptation of this technology will encourage creation of a profitable and waste-free production.

The scientific group has discovered that on the average each ton of waste produced by burning coal at the power plants and boiler stations at the Russian Far East contains 2.5 grams of gold. This is an average level by the industrial measurement. As of today, major rich ore deposits are already depleted and the content of 2 or 3 grams of gold per ton is considered to be medium-rich.

Major stages of extraction technology include fractional separation, breakage of the raw material and complex extraction of needed elements with the help of gravitational, electromagnetic and vibrational exposure and flotation. The extracted concentrate is supplied later for chemical processing, which utilizes widely used non-hazardous chemicals. A processed left-over stock gets into becoming construction materials. The processing also extracts sand and coal, which has not burnt. The former one is used as a construction material while latter one returns to the power stations again as a fuel.

This method allows to solve a major problem of extraction of precious metals from the ash waste, a problem which cannot be addressed by standard gravitational method due to the small size and plate-like shape of the metal particles. Besides, until fairly recently environmentally friendly technologies of extraction of valuable components of the ashes did not exist.

At this point of time, the Laboratory studies samples collected from the ash disposal areas of the power plants of Primorsky krai. The findings of this study will help better assess the gold content of specific types of ash waste.