FEFU researchers suggest raising precious metals from coal ash

Feb. 16, 2015 - PRLog -- The methodology allows to get gold, platinum and several sorts of construction materials from the processed ashes: bricks, roof tiles, insulants, masonry products, and paving stone. Implementing this technology will allow creating a profitable and non-waste industrial enterprise.

The research group has found out that each ton of waste of the combustible material burned at power plants and boiler stations of the Far-Eastern region contains in average 2.5g gold. According to industrial measures, it is an average-level value. At the present moment, the basic rich ore deposits have been mined out and if a ton ore contains 2-3g gold, the deposit is considered to be profitable.

‘We have developed an experimental technology the main process stages of which suggest fractional separation, raw material fine crushing and complex raising of valuable elements using a combination of gravitational, electromagnetic, vibration, ultrasound processing and flotation. The resulting concentrate is supplied for chemical processing with widely used non-hazardous elements. And the remaining “clear tail” is sent for construction materials manufacturing. Also sands and unburned coal are separated during this process. The formers can be sent for construction recycling, too; the latter can be returned to power plants as fuel’, deputy head of the project, head expert of FEFU’s industrial cooperation development department Andrey Taskin says.

The method allows to solve the basic problem of raising precious metals from ash cinders which cannot be solved using the standard gravitational method due to small size and complex shape of the particles. Besides, no environmentally clean technologies of separating valuable components from ash cinders have existed until recently, the expert notes.

‘The methods already known do not solve the priority problem of waste elimination: after using them, a big “anthropogenic tail” remains anyway and it requires recycling. Coal waste repositories, dumps of coal industry, occupy large territories. About 30 million tons of ash and cinders are dumped only in Vladivostok on the area of about 150 hectares. We suggest complex recycling of anthropogenic waste with positive economic efficiency of a large-capacity industrial enterprise’, Andrey Taskin reassures.

The FEFU’s project accomplishment is planned for two years and supported by the Federal Target Program Research and Development in Priority Development Fields of the Research and Technology Complex of Russia for 2014-2020. The project has also an industrial partner, Ecomett LLC, which is interested in industrial implementation of the technology.

The samples collected at ash disposal areas of Primorsky Krai’s power plants are tested in the laboratory at the present moment. The tests’ results will help to evaluate the gold content of each coal waste repository more precisely and determine the rational combination of technologies for recycling it.