TECHNICAL NOTE GOLD LOSSES FROM CYANIDE SOLUTIONS PART II: THE INFLUENCE OF THE CARBONACEOUS MATERIALS PRESENT IN THE SHALE MATERIAL

摘要

Gold was found to be mainly adsorbed onto the carbonaceous particles in the Beatrix shale material with possible minor loss of gold due to co-precipitation of gold with Mg(OH)_2 and Fe(OH)_3.Two types of carbonaceous material were present in low concentrations in the Beatrix shale and resembled kerogen. The one type can be described as filamentous particles and the other as roundish particles. Rank measurements done on the carbonaceous particles in the shales showed that they fall in the anthracite range. Adsorption of gold on carbonaceous material of similar rank showed that anthracite has the highest propensity to adsorb gold. This suggests that the carbonaceous particles would have similar gold adsorption properties as anthracite. The lack of an obvious correlation between the propensity of a shale to adsorb gold and its carbon content is probably due to the fact that not all the carbonaceous particles are liberated during milling so that they can be brought into contact with the gold cyanide solution.