BASED ON BIOGEOCHEMISTRY OF METALS AND REAL WORLD

PROBLEMS

MERCURY AS EXTREME EXAMPLE

SLUICING AND GRAVITY CONCENTRATION OF GOLD RICH SOIL

From Ghana, West Africa – Miners working at a slucing center. Mining wastes released into a waterway

EXAMPLE AMALGAMATION PROCESS

From Ghana, West Africa – A miner mixing liquid mercury (Hg0) with washed gold using bare hands.

MERCURY – GOLD AMALGAM

Source: From CEEST-Tanzania – Miners working on amalgamated gold.

CLOTHE FILTRATION SQUEEZING Hg-Au AMALGAM

AMALGAM TORCHING / BURNING

COULD BE A FAMILY AFFAIR!!!!!!

PROBLEM

In AGM, Hg0 is used in gold extraction from crude ores in processes that use water to facilitate the recovery of gold. This step generates Hg-contaminated water which is intentionally released into waterways. This initial extraction step is then followed by a purification step in which the Hg-Au amalgams is torched in either open air or in confined and secret locations to burn off the mercury. These extraction and purification processes have negative implications for water and air quality as well as human health.

Based on your current knowledge of biogeochemistry of trace metals, develop a low-cost technology using “in-country materials” to accomplish the following:

(1) trap and recover mercury from aqueous and gaseous waste effluents produced in artisanal gold mining

(2) recycle the recovered mercury by regeneration of used mercury adsorbents—as the recycling of recovered Hg could be used as incentive to facilitate the implementation of the developed

technology.