Key ideas: Intermediary, chemical effect, "nested doll", biological effect
The problem of gold mining is displayed as a string of problems. First, you use the Intermediary Principle, then you solve the problem by the Chemical Effect, and finally you use the Biological Effect according to the US patent 05378437 "Processes to recover and re-concentrate gold from its ores". By the way, you remove a contradiction in space (by the "Nested Doll" Principle).
Once you could read in the books that gold is mined from gold sand. "Washing out" is the methods name. You have to simply separate the gold grains from the rest ore. Now I ask you: suppose it goes this way till now. What is the ratio between pure gold and gold ore? 1:10? 1:100? Wrong. Today gold is recovered from ore body containing
gold in an amount of 0.02 oz/ton. It is very low. You cant see the gold grain, you cant wash it out, you cant seize it with magnet. So you need another method. Which one do you think?
hint. The Intermediary Principle says to merge one object temporarily with another (which can be easily removed).
But gold has little susceptibility to adhesion, or reaction, or any merging with other materials. Gold is one of the least reactive metals on earth. It does not combine with oxygen or with nearly any other chemicals, no matter how corrosive. So you have the problem: what can you attach to gold when nothing attaches to it?
MIDWAY SOLUTION. There is a chemical effect: gold does combine with cyanide, however. What are cyanides? These are potassium cyanide, cyanic acid -- briefly, all those containing CN group.
All of the commonly used industrial methods for
removing gold from ores require the use of cyanide. The cyanides are
brought into contact with gold ore, causing production of "gold ion
cyanide ion" complexes:
Finally, the pure gold is recovered from these complexes it is not a problem. So what is the problem? Cyanide is highly toxic, hazardous to the environment and difficult to remove. It is responsible for several environmental impacts, including air and water pollution. Although cyanide will degrade, for example, in a surface exposed to ultraviolet light, aeration and complexing with various chemicals present in the water, such degradation is a wholly unsatisfactory approach to removing cyanide from the environment. Cyanide solutions are often kept in open ponds and frequently birds or other animals are exposed and killed by the toxic material.
So, the contradiction looks like this: the cyanides must be to recover gold but must not be in order not to harm the environment.
THE CONTROL ANSWER. Biological Effect: some microorganisms (algae, fungi and bacteria) are capable of producing cyanide ion. By the way, blue-green algae are known as cyanobacteria and/or photosynthetic bacteria.
Let us mark the main stages of this method according to the US patent 05378437:
1) Culturing microorganism species capable of producing cyanide ion, thus forming a cyanide ion containing and producing culture.
Here is the exact formula of the reaction (such a
reaction is called "cyanogenesis"):
2) Contacting the cyanide ion containing and producing culture with gold ore, thereby causing production of "gold ion cyanide ion" complexes and dissolution of gold from the gold ore.
There are several possibilities of such complexes:
3) Removing, by biosorption, "gold ion cyanide ion" complexes from solution to said culture.
4) Reclaiming gold from said culture by further refining: e. g., through drying (dehydration) the microorganisms.
So, the contradiction "the cyanides must be and must not be" is removed according to the "Nested doll" Principle: the cyanide is inside the microorganism but is absent on the outside.
Now you might ask: what about the cyanides that do
not take part in the process and remain after everything is over,
therefore still endanger the environment? One of the microorganisms
releases ammonia from cyanide with the following stoichiometry: