How is Gold's atomic structure and bonding related to the separation techniques used to distinguish it from other substances?

I'm just confused on what I'm actually searching for, I have read so many blogs on Gold extraction, refinement, occurences and more topics, and either I'm skipping the important parts or the answer's just not there. What can I search to find what I'm looking for? The separation technique I chose is flotation, can someone lead me in the correct path and/or give me a few hints on what to start of with? Thanks in advance, much appreciated!


1 Answer 1


There are differences in gold extraction for different mines - depending on the chemical nature of the raw ore, the impurities present, the availability of resources etc.

A good example of gold extraction comes from the Super Pit mine in Kalgoorlie, Western Australia; their gold extraction process is outlined in their website Mineral Processing, which is outlined below:

Crushing and grinding: this is a physical process where the mined raw ore is crushed, ground and water added to make a slurry.

Flotation: chemicals are added to the slurry to remove everything other than gold and pyrite. Water is also removed at this stage. The slurry is agitated forming air bubbles, which then rise through the slurry, carrying mineral grains. From Introduction to Mineral Processing:

The ability of a mineral to float depends upon its surface properties. Chemical modification of these properties enables the mineral particles to attach to an air bubble in the flotation cell. The air bubble and mineral particle rise through the pulp to the surface of the froth or foam that is present on the flotation cell.

Roasting: water is re-added and the concentrated slurry is roasted to remove $\ce{SO2}$

CIL: or carbon in leach, chemicals are added to dissolve the gold and have close to pure gold precipitate on the carbon.

Elution: A mixture of caustic soda and cyanide is used to liberate the gold from the carbon.

For your specific request for resources about flotation, the example process below is for a sulphide copper ore containing iron bearing pyrite:

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(Image Source)

Suggested additional resources about flotation:

Froth Flotation – Fundamental Principles

A great resource is the book Handbook of Flotation Reagents: Chemistry, Theory and Practice (chapters are behind a paywall).

  • $\begingroup$ Thank you so much! You have no idea how much you have helped me! Would $SaOH^- + CN^-$ be the only chemical reaction encountered in the separation process? And in which stage would I be able to establish the relation between gold's atomic structure and bonding, I am guessing that the "Elution" process plays a big part, does the sodium hydroxide and the cyanide affect gold in any chemical way? $\endgroup$ Mar 2, 2014 at 1:14
  • $\begingroup$ This may be of interest for that stage rsteyn.files.wordpress.com/2010/07/… One clarification from your comment, the formula for sodium hydroxide is $NaOH$ $\endgroup$
    – user4076
    Mar 2, 2014 at 1:25
  • $\begingroup$ Sorry! $NaOH$, I got it a bit mixed up with the cyanide formula. Does that mean that $SaOH + CN^-$ is the only occuring chemical reaction, or will I find out more after I thorougly read what's behind the link you provided? Is there a specific terminology for the relationship between atomic structure and bonding to the separation process (floation) used? Thank you again! $\endgroup$ Mar 2, 2014 at 1:38
  • $\begingroup$ @SamirChahine These may help answer your question saimm.co.za/Journal/v077n12p254.pdf and eng.nus.edu.sg/m3tc/M3TC_Technical_Reports/… $\endgroup$
    – user4076
    Mar 3, 2014 at 9:16

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