At room temperature, gold is crystal, equiaxed crystal system, cubic lattice, and its natural good crystal morphology is extremely rare, and it is often irregular granular, massive, flaky, reticulate, dendritic, fibrous and spongy aggregate. Pure gold is golden yellow, and its color will change accordingly when it contains impurities.
Gold ore refers to the ore containing gold element or gold compound, which can be processed into gold concentrate or gold ore with high gold grade. Gold concentrate needs to be smelted into refined gold and gold products. Therefore, gold can't be artificial.
Extended data:
Gold refining technology:
1, gold concentrate roasting:
Gold in most refractory ores is closely related to the formation of sulfide. Using flotation method, gold-bearing sulfide can be fully and effectively enriched, gold concentrate can be produced, and high flotation recovery rate can be obtained. Because of the complex composition of flotation gold concentrate and the high content of beneficial and harmful elements, the leaching rate of gold by direct cyanide leaching is low. Therefore, roasting oxidation pretreatment of this kind of refractory gold concentrate is one of the effective methods to improve the gold leaching rate.
2, hot pressing oxidation process:
Hot pressing oxidation can be divided into acidic hot pressing oxidation and alkaline hot pressing oxidation. Alkaline hot-pressing oxidation is suitable for refractory gold-bearing ores with high carbonate content, and acidic hot-pressing oxidation is suitable for refractory gold concentrates containing sulfur and arsenic, so the application of acidic hot-pressing oxidation process is more extensive.
Hot-pressing oxidation is the oxidative decomposition of pyrite and arsenopyrite at a certain temperature and pressure, so gold particles will be dissociated no matter how small they are, which makes the leaching rate of gold higher. After pressure oxidation of many refractory gold concentrates, the leaching rate of gold can be as high as 96%. However, it is difficult to eliminate the "gold grabbing" effect of organic carbon, so the application of this process is limited for gold concentrates with high organic carbon content.
3. Combined pretreatment process:
For the typical refractory gold concentrate with complex composition, many kinds of interfering elements and high content, it is difficult to obtain the best effect by using a single pretreatment process. For example, if the concentrate contains antimony and organic carbon, if the carbon is removed by roasting, antimonate and antimony alloy will be formed during roasting because of the low volatilization temperature of antimony, which will form a secondary package for gold, which will seriously hinder the leaching of gold.
If biological oxidation or hot-pressing oxidation is used to remove carbon, although these methods are not sensitive to antimony, they cannot destroy the structure of organic carbon and eliminate its "gold robbery", so the leaching index of gold will also be greatly affected. Due to the mutual restriction and conflict between antimony minerals and organic carbon, and the influence of other interfering elements, the application of single pretreatment process is limited.
Baidu Encyclopedia-Gold Mine (Gold Mine)
Baidu Encyclopedia-Gold (Precious Metals)