Aqua Regia Safety, Filtering the Fumes
Using Coconut Carbon to Filter Toxic Aqua Regia Fumes
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Aqua regia is widely used for leaching gold, platinum and palladium and is one of the few chlorine leaching solutions that will dissolve gold and other precious metals.  The aqua regia gold leaching process is an excellent choice for leaching gold into solution, as long as the corrosive and toxic fumes from the aqua regia are captured and filtered.  This article discusses  aqua regia safety and a simple device that can help control the toxic and highly corrosive fumes from aqua regia and other chlorine leaches, by simply adding an activated coconut carbon filter.
The aqua regia gold leaching process is used by many small gold processing companies, jewelers and individuals.  Many prospectors who are processing gold, use the aqua regia gold leaching process for their fine flour gold recovery.  Jewelers use aqua regia, and other chlorine leaching formulas, to refine their precious metal bench sweeps.  Here at Gold River Refining we have developed an inexpensive activated coconut carbon filter that can easily be added to standard  gold leaching glassware.
By using a boiling flask instead of a beaker to hold the gold leach, an activated coconut carbon filter can be easily placed into the ground joint of the boiling flask.  Using a boiling flask, instead of a beaker, when leaching gold and other precious metals, allows you to create a tight joint between the boiling flask and the activated coconut carbon filter unit. This forces the toxic aqua regia fumes up and through the super activated carbon filled glass sphere, where many of the toxic fumes are adsorbed by the activated coconut carbon. 
Glass Carbon Filter Aqua Regia Fumes Safety
To use the glass filter unit, simply place a small piece of ph paper directly on top of the activated coconut carbon to visually  see when the carbon has adsorbed as much of the highly corosive aqua regia fumes as it can. When the coconut carbon is fully saturated with toxic fumes, the ph paper will turn from green to red and you know that it is time to replace the activated coconut carbon.  To do this, simply pour out the old activated coconut carbon and replace it with new activated coconut carbon. 
This simple glass carbon filter can be used with other gold leach formulas and is not limited to aqua regia.  It works with many chlorine leaching formulas and can be used with other gold leaching glassware pieces that use a standard  24/40 ground joint.
Buy Activated Coconut Carbon
Jewelers and gold refiners can now leach gold, using this gold refining / processing technique that utilizes activated coconut carbon to help control the fumes from aqua regia.  Using this gold leaching setup, one can  help protect  the environment by capturing toxic fumes with activated coconut carbon.  This is not a replacement for a fumed hood.  Always use a fumed hood with an appropriate sized scrubber when using aqua regia or any precious metal leach. This carbon filter unit should be used inside a fumed hood as an added measure of fume control before going through the scrubber.  
You can buy activated coconut carbon  from our online store, as well as glass carbon filters, adapters, and gold leaching glassware and equipment .