Extract gold without using mercury

So, Homie, what's gold?   

BA

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http://www.thunting.com/smf/index.php/topic,19946.msg230923.html#msg230923

I'll let you off the hook.   Whether it is a mineral or not depends in large part upon its state.  Once it is processed, it is no longer a mineral in the geologic source (same thing applies for gold, silver, etc)   Mercury as a mineral is rare but possible.

Definition of a mineral taken from Wikipedia:

Basic definition
The general definition of a mineral encompasses the following criteria:[2]
Naturally occurring
Stable at room temperature
Represented by a chemical formula
Usually abiogenic
Ordered atomic arrangement
The first three general characteristics are less debated than the last two.[2] The first criterion means that a mineral has to form by a natural process, which excludes anthropogenic compounds. Stability at room temperature, in the simplest sense, is synonymous to the mineral being solid. More specifically, a compound has to be stable or metastable at 25°C. Classical examples of exceptions to this rule include native mercury, which crystallizes at -39°C, and water ice, which is solid only below 0°C; as these two minerals were described prior to 1959, they were grandfathered by the International Mineralogical Association (IMA).[3][4] Modern advances have included extensive study of liquid crystals, which also extensively involve mineralogy. Minerals are chemical compounds, and as such they can be described by fixed or a variable formula. Many mineral groups and species are composed of a solid solution; pure substances are not usually found because of contamination or chemical substitution. For example, the olivine group is described by the variable formula (Mg, Fe)2SiO4, which is a solid solution of two end-member species, magnesium-rich forsterite and iron-rich fayalite, which are described by a fixed chemical formula. Mineral species themselves could have a variable compositions, such as the sulfide mackinawite, (Fe, Ni)9S8, which is mostly a ferrous sulfide, but has a very significant nickel impurity that is reflected in its formula.[5][2]
The requirement of a valid mineral species to be abiogenic has also been described as similar to have to be inorganic; however, this criterion is imprecise and organic compounds have been assigned a separate classification branch. Finally, the requirement of an ordered atomic arrangement is usually synonymous to being crystalline; however, crystals are periodic in addition to being ordered, so the broader criterion is used instead.[2] The presence of an ordered atomic arrangement translates to a variety of macroscopic physical properties, such as crystal form, hardness, and cleavage.[6] There have been several recent proposals to amend the definition to consider biogenic or amorphous substances as minerals. The formal definition of a mineral approved by the International Mineralogical Association (IMA) in 1995:
A mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes."[7]
In addition, biogenic substances were explicitly excluded:
"Biogenic substances are chemical compounds produced entirely by biological processes without a geological component (e.g., urinary calculi, oxalate crystals in plant tissues, shells of marine molluscs, etc.) and are not regarded as minerals. However, if geological processes were involved in the genesis of the compound, then the product can be accepted as a mineral."[7]



BA

Posted on: August 16, 2012, 06:41:12 PM

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so native gold would be a metallic elemental mineral    (meaning it is a mineral made up of a a single metallic element).   If you took the native gold and melted it down and poured it into a bullion bar, it would still be an element and still be a metal, but it would no longer be a mineral

BA

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http://www.thunting.com/smf/index.php/topic,19946.msg230928.html#msg230928

I concede the point. It is possible for both of us to be correct. Mineral, metal, whatever. Mercury occurs naturally in the environment. It is like many other naturally occurring substances, harmful if ingested or encountered without precautions being taken. Please recall that I state I am not a proponent of the use of mercury. That means I am not in favor of it's use. We (I) are (am) spending time and money to educate, and to show by example that mercury use can be replaced by modern capture methods. Not quite sure why you felt it necessary to say I do not know what I am talking about, and do not really care. Your opinion is just that, your opinion and you are entitled to it. Do to our (my) direct involvement, the use of mercury is declining in the areas where we work. We discontinued the use of mercury quite some time ago, and have shown by our example that gold recovery could actually be increased without the harm to the environment, employee health concerns, and expense that can be attributed to the use of mercury.

I appreciate the interaction on this important subject, and hope that you come to realize I do not necessarily disagree with you in principle, just in your antagonistic attitude.



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http://www.thunting.com/smf/index.php/topic,19946.msg230931.html#msg230931

Yeah, actually IF you can find mercury  in it's pure native state (which you can generally do if you look really close at many cinnabar (also a mineral) samples), you can see it as mineral (it won't look much different than the processed stuff).....BUT even then, it is still a metal just like that prized piece of specimen gold in the museum's mineral collection is a metal even though it is a legitimate mineral specimen.  

So, the mercury used in the recovery of gold should correctly be referred to as a metal not as a mineral since it has been extracted via human intervention from the mineral ore that contained it.

BA

By the way, thank you both for a fun and enlightening conversation.   Hopefully everyone learned something useful.

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http://www.thunting.com/smf/index.php/topic,19946.msg230939.html#msg230939

I live about 25 miles from the Infamous (superfund) Black Butte mercury mine, both of our reservoirs have mercury contamination one from the mine and the other from gold mining activity. There are several outcroppings of cinnabar in the area and the town that used to be at the base of the butte was known in the early 20th century for its "mercury springs water" which was bottled and sold. If you handle it properly it is perfectly safe, however they used to coat the copper wash plates at the stamp mills with mercury and lost a lot downstream. The old miners said they would scrape the plates and roll the gold / mercury amalgam into a ball then put inside a potato which went into the fire, the mercury would off gas and leave the gold behind. I found a coffee can with about 25 lbs of mercury in my garage after we bought the place. I stupidly took it in to the hazardous materials disposal before I found out it was worth big bucks.  

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