Typically, when gold ore is mined from the ground, its crushed to a powder and passed through a series of tanks in a procedure called seeping. Cyanide is then utilized to separate the gold from the ore into the seeped solution.
With the new process, the leaching and healing procedure is finished with chloride, one of two elements in salt.
” Until now, nobody has actually established an excellent technique for recovering small quantities of gold from industrial chloride solutions,” states Ivan Korolev, a researcher on the task and doctoral candidate.
” With our process, the quantity of gold weve been able to recover using chloride is as high as 84%. In contrast, utilizing the basic cyanide process with the same ore yielded just 64% in our control experiment,” he describes.
Called electrodeposition-redox replacement (EDRR), the brand-new procedure combines the best of 2 common techniques for extracting seeped gold: electrolysis, which uses electrical currents to decrease gold or other metals present in the seeping service, and cementation, which includes particles of other metals to the service to react with the gold. Teacher Mari Lundström and University Lecturer Kirsi Yliniemi, from Aalto Universitys School of Chemical Engineering, are behind its advancement.
” With EDRR, we use short pulses of electrical power to produce thin layers of metal– in our case copper– on the electrode and cause a reaction that motivates gold to replace the copper layer by layer,” states Korolev. “The technique has low energy intake and doesnt require the addition of any other components.”
Industry-level partnership
The research was performed as part of a wider EU sustainability task called SOCRATES, and the work was performed in cooperation with Finnish mining-technology giant Metso Outotec. The majority of the experiments were carried out at the companys research center in western Finland.
” Collaborating with Metso Outotec permitted us to establish the technique in a manner thats much closer to real-world implementation,” says Korolev. “We began with about 9% recovery, however it then grew to 25%, and quickly we were hitting 70%– in some cases we even achieved near 95%.”.
” Its something to do an experiment like this on a small scale, however nobody had ever done it at the scale that we have done. We revealed that although our method is still truly new, there is a lot of capacity for making it an effective option to the standard industrial procedure,” he states.
” Until now, nobody has developed a good method for recovering percentages of gold from industrial chloride services.”– Ivan Korolev.
” The extraction techniques of the past have constantly left some valuable metals behind. Now, as demand for metals grows all the time, even these percentages are necessary,” he says. “I believe we can still increase the yield with our EDRR technology. Maybe we can not reach 100%, however I think we can strike the 90% mark or more.”.
” It would be terrific to see a mining business thinking about this technology and ready to check with their ore on site.”.
Korolev has a really individual interest in the task too. Born in the Siberian mining town of Kemerovo, he grew up seeing both the favorable and the unfavorable sides of the industry. When studying mining engineering– first in Russia and then in numerous European universities– Korolev became interested in metallurgy and the recovery of waste materials.
” The extraction methods of the past constantly left some valuable metals behind. Maybe we can not reach 100%, but I think we can strike the 90% mark or more.”.
Reference: “Electro-hydrometallurgical chloride process for selective gold healing from refractory telluride gold ores: A mini-pilot research study” by Ivan Korolev, Pelin Altinkaya, Mika Haapalainen, Eero Kolehmainen, Kirsi Yliniemi and Mari Lundström, 8 September 2021, Chemical Engineering.DOI: 10.1016/ j.cej.2021.132283.
Gold. Credit: Robert von Bonsdorff/Aalto University
Study reveals new chloride-based process recovers 84% of gold compared to the 64% recovered with standard approaches.
Gold is among the worlds most popular metals. Flexible, conductive and non-corrosive, its used in fashion jewelry, electronics, and even space expedition. However traditional gold production typically includes a well-known toxic substance, cyanide, which has actually been prohibited for commercial use in a number of countries.
The wait for a scalable non-toxic option may now be over as a research group from Aalto University in Finland has actually successfully changed cyanide in an essential part of gold extraction from ore. The results are published in Chemical Engineering.
Gold is one of the worlds most popular metals. Standard gold production typically includes a popular contaminant, cyanide, which has been prohibited for industrial usage in a number of nations.
” The extraction methods of the past have always left some valuable metals behind. Perhaps we can not reach 100%, but I think we can strike the 90% mark or more.”.
Possibly we can not reach 100%, but I think we can strike the 90% mark or more.”.