Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gold without poison

25.02.2008
Researchers from the Krasnoyarsk State University together with their colleagues from the Institute of Chemistry and Applied Chemistry, Siberian Branch, Russian Academy of Sciences, also located in Krasnoyarsk, have developed an original method for extracting gold and silver from multicomponent solutions.

The peculiarity of the suggested technology is that chemists have ultimately managed to find an adequate and fundamentally less toxic replacement to cyanide – the reagent which is widely applied for extracting gold from ore and recyclable materials and which is even called a “poisonous companion of gold”. It is the very poison the detective story authors like so much but river and lake inhabitants dislike so much.

They dislike it to such extent that they simply die – this happened, for example, to fish in the Danube, when in 2000 cyanide got into the Tisa river and then from it – into the Danube through a small Austrian gold-mining company’s fault. The company used cyanide to extract gold and silver from solutions. However, not only fish suffered – a lot of birds and wild animals died, millions of Hungary inhabitants were deprived of drinking water.

Basically, the method developed by the Krasnoyarsk chemists does not differ fundamentally from the known one. In both cases, the reagent is added to complicated solutions containing a noble metal– for example, after ore dissolution, or as the specialists put it, opening up of ore. The reagent forms a complex both with gold and silver. Thus a compound is obtained, in which the central atom of the metal is surrounded by several ions – either those of cyanide (as usual), or of thiocyanate (a new method).

The entire construction is an anion, and it can be further extracted from the solution on the so-called ion-exchanging column – chlorine ions can be “changed” (they go into the solution) for composite ions that contain the noble metal in the ion-exchange resin filling the column.

Then these ions, certainly together with silver and gold should be washed off the column, and the target metal should be educed from this solution – it can be reduced electrolytically or by any other method.

However, this seems simple only on paper. But in real life chemists had to perform tremendous work to select the most efficient sorbent and conditions of dealing with it to “catch” maximum noble metal from the solution and then to wash all of it off the column, it is desirable to do that separately. And they have succeeded in doing that.

The researchers not only investigated the sorbtion mechanism of thiocyanate complexes of gold and copper on very different sorbents, but they also discovered those that enable to extract practically all noble metal from the solution. Moreover, having designed the necessary methodology, the authors learned to fully separate gold and silver, varying the solution composition, which “washes off” the target metal from the sorbent. Besides, the researchers developed and patented the method that allows to determine the gold content directly in the sorbent, but not in a ready solution. Of course, this is very convenient – because this allows to learn exactly how fully the noble metal was extracted from the initial solution and then – how fully it was extracted from the sobent.

In brief, the researchers have developed an excellent method for extracting gold and silver – it is efficient and much less poisonous the traditional method. Cyanide is almost one hundred times more toxic than thiocyanate. So, the Krasnoyarsk chemists have managed to relieve gold at least one poisonous companion – cyanide.

Olga Myznikova | alfa
Further information:
http://www.informnauka.ru

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>