No. 1688, Gaoke East Road, Pudong new district, Shanghai, China.
No. 1688, Gaoke East Road, Pudong new district, Shanghai, China.
Mercury-based artisanal and small-scale gold mining (ASGM) causes more mercury pollution than any other human activity. 1 In this practice, mercury metal is used to extract gold from ore as a stable amalgam. The amalgam is then …
Mercury first was used to extracting gold as many as 3,000 years ago. The process was prominent in the U.S. up until the 1960s, and the environmental impact on northern California is still felt today, according to sciencing .
Miners dig up ore and sediment containing gold, then add mercury to help extract the precious metal. They then burn the mercury off — often in huts where miners and their families live — leaving the gold behind. The process is cheap, easy and accessible.
Learn about how mercury and gold interact, how mercury is used by artinanal small-scale miners and why its use is a health and environmental hazard.
Take a clean, large, copper gold pan and coat thoroughly with mercury, using a pad of folded cloth. Deposit the concentrates in the pan, add some fresh water and swirl and agitate until all-visible gold has been taken in by the mercury.
Although many miners use mercury in artisanal and small-scale gold mining, it is possible to safely and economically recover gold without it. Mercury-free techniques are safer for miners, their families and local communities. They may …
Mercury forms a mercury-gold amalgam with smaller gold particles, and then the gold is concentrated by boiling away the mercury from the amalgam. This is effective in extracting very small gold particles, but the process is hazardous due to the toxicity of mercury vapour.
Mercury is used to extract gold by forming a gold–mercury amalgam in artisanal and small-scale gold mining (ASGM). Almost all of this mercury is lost to the environment when the amalgam is heated to purify the gold, at an estimated 1400 metric tons per year ( UNEP, 2015 ).
Just as water is an effective solvent of many substances because of its chemical composition, mercury's atomic structure makes it an effective solvent of most metals. This, combined with its low boiling point, make it useful for extracting gold from ore in a process of amalgamation and distillation.
Miners use mercury in the field to extract gold from ore, heating the resulting mixture to remove the majority of mercury and produce impure gold that can be sold. Then, gold shop owners melt the impure gold, releasing the remaining mercury into the air.
