Main Gold Bearing Minerals
This criteria along with other supplementary information that are relative to deposits themselves, and due to the difficulty of the starting up of certain metallurgic operations, allow us to establish a treatment process of the gold mineral. Some examples are shown:
This note concludes about the current tendencies of the treatment of gold minerals and the techniques in development (usage of carbon in pulp, in particular with the clayish minerals, usage of new lixiviation reagent such as thiourea). From the economical point of view, the mineral that has a great amount of dominion is gold in its metallic or natural state, the same that can revert in a great variety of ways and dimensions in the different deposits. The more currently found particles of gold have dimensions that vary between a dozen of microns and a dozen of millimeters; the masses of gold that weigh between 50 and 100 Kg. have been found in quartz veins. The texture of natural gold varies importantly in the same way and notable in function in its origin and secondary functions (detrital character, metamorphic removal or precipitations starting from oxidant solutions, sulfate, and chlorides). Natural gold has a variable purity (between 45 and 100 percent Au) that depend mainly on its origin: silver (average content of 10 percent) is the main impurity that can be found; copper and iron can in the same way, have slight content and be in the same way associated with gold. One particular case constitutes the natural alloy with silver, denominated electrum. Telluriums make up the second type of important economic gold bearing minerals. These often times have, in addition, remains of mercury. They are sometimes accompanied by natural gold (volcanic or tertiary mineralization or Precambrian mineralization). In the lighter contents, there can even be one hundredth of ppm, the gold can be found associated to sulphides such as pyrite mainly or pyrrhotite, galena and sphalerite, under a form that is not visible and where the help of classic mineralogy instruments are needed (optical or electronic microscope). In general gold presents itself in a for of sub microscopic inclusions of natural gold, although some believe that this can come about in a solid solution in the inside of sulphurs. We point out finally, the rarest existence of auriferous make up based on bismuth or antimony.