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Posted 07/28/2011 8:50 pm
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In Western Australia, gold is mined in the mineral telluride, which is also a complex gold double salt in association with tellurium. Again, I do not know if this mineral is soluble or not. I guess that gold is recovered from telluride by the simple application of heat.
In Western Australia, gold is mined in the mineral telluride, which is also a complex gold double salt in association with tellurium. Again, I do not know if this mineral is soluble or not. I guess that gold is recovered from telluride by the simple application of heat.
I have no experience with material of that type, so cannot advise anyone of how it should be handled. Search the Internet for gold refining processes to see what the usual industrial purification methods are. If various ores are mentioned, they should have different purification processes.
Many complexes can be broken down by heating them strongly. Most often, this results in the ejection of small molecules, such as water, ammonia, or H2S. Note that H2S has considerable toxicity and that an early symptom of H2S poisoning is euphoria and a loss of cognitive capacity... a VERY dangerous combination.
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How fine must the gold alloy particles have to be?
How fine must the gold alloy particles have to be?
How high is the sky? Questions like this don't have a direct answer and depend on the purity level you are trying to reach. The smaller the particle, the higher the surface area, and the greater the removal of surface impurities will be. The ultimate in this is, of course, when the gold is completely dissolved and exists in solution as a gold molecular complex of some kind.
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I suppose pH management would control this preference.
I suppose pH management would control this preference.
Yes, good pH control would be necessary to maintain the amount of acid available for impurity extraction and solution. A way of adding fresh acid to the mixture as the purification process completed would also be needed. This can be a tricky step, as acid additions will result in different pH changes depending on how quickly the acid is consumed. Good mixing of such solutions is critical so that pools of highly concentrated acid do not float around in the solution but are quickly dispersed throughout the solution. A homogeneous or nearly homogeneous solution should work the best but maintaining that homogeneity during the purification process can be tricky.
Various catalysts are produced for the chemical industry by making an alloy of, say, nickel with aluminum. This is made in blocks that are then milled to a specific granule size. An aqueous solution of NaOH is then added to a stirring slurry of the catalyst granules. The caustic soda leaches out some of the aluminum, creating a "sponge nickel" catalyst. These can be "hot", in that they are so reactive, they will sometimes burst into flame when allowed to dry out in the presence of air. While this process is done on purpose to generate a particular catalyst, the effect that occurs during its manufacture could be similar to what you would achieve with your gold purification. Not that any gold sponge that results would likely be pyrophoric, of course.
