Oxidized gold ore is mainly composed of gold oxide and various associated minerals, and its chemical composition is relatively complex. Gold often exists in the form of fine particles and coexists with oxides of metals such as iron, lead, zinc, and copper. This complex composition makes the gold extraction process very difficult.
Common types of oxidized gold ores include quartz-type oxidized gold ores, pyrite-type oxidized gold ores, and limonite-type oxidized gold ores. Different types of oxidized gold ores have different requirements for the dressing process due to their different mineral components and forms.
Gold has a fine particle size and is difficult to recover effectively. Gold exists in the ore as fine particles, and traditional beneficiation methods are difficult to fully recover it.
Gold is closely combined with associated minerals and is difficult to separate. Gold is closely combined with various associated minerals, making the separation process complicated and difficult.
Traditional physical and chemical beneficiation methods are ineffective for some oxidized gold ores. Due to the particularity of oxidized gold ores, some traditional mineral processing methods are not effective when processing certain oxidized gold ores.
(1)Grinding process
The grinding process of oxidized gold ore usually adopts a process flow combining open-circuit grinding and closed-circuit grinding. Open-circuit grinding can initially crush the ore. In this process, larger pieces of ore are quickly decomposed into smaller particles, which improves the overall grinding efficiency. Closed-circuit grinding can further grind the ore so that the gold particles can be better separated from the ore and the gold recovery rate can be improved. By reasonably adjusting the parameters of open-circuit and closed-circuit grinding, efficient processing of oxidized gold ore can be achieved.
(2)Gravity separation process
Gravity separation plays an important role in the beneficiation of oxidized gold ore. It mainly separates iron-containing minerals and other impurities through flotation, gravity separation, magnetic separation and other methods, thereby improving the grade and recovery rate of gold. In the gravity separation process, the density difference between minerals is used to separate heavier impurities such as iron-containing minerals from lighter gold particles. This can effectively remove impurities, enrich gold, and provide higher quality raw materials for subsequent process steps.
(3)Cyanide leaching process
The cyanide leaching process of oxidized gold ore usually adopts alkaline leaching. This method can reduce the amount of cyanide used and reduce environmental pollution. In the cyanide leaching process, parameters such as leaching temperature, time, and pH value need to be strictly controlled. The appropriate leaching temperature can promote the reaction between gold and cyanide and improve the leaching speed and efficiency. The length of leaching time will also affect the recovery rate of gold. Too short a time may cause the gold to not be fully dissolved, while too long a time may increase costs and environmental risks. At the same time, it is also very important to control the pH value of leaching. The appropriate pH value can ensure the stability of cyanide and the dissolution effect of gold.
(4)Concentration process
The concentrating process uses gravity separation, flotation, magnetic separation and other methods to further improve the grade and recovery rate of gold. Through the combined use of these methods, gold can be separated and enriched more finely. Gravity separation can use the density difference between gold and other minerals for re-separation; flotation can make gold particles attached to bubbles for recovery according to the different surface properties of minerals; magnetic separation can remove magnetic impurity minerals and improve the purity of gold. The selection process can effectively improve the quality of gold and lay the foundation for the final high-grade gold products.
(1)Innovative methods of pre-oxidation treatment
Pre-oxidation treatment is an important means to enhance the recoverability of gold. The new pre-oxidation treatment method includes the use of high-efficiency oxidants and specific oxidation conditions, which can effectively destroy the combination of gold and associated minerals. In this way, gold is easier to separate in the subsequent mineral processing process. For example, the use of specific high-efficiency oxidants, under specific temperature and pressure conditions, can effectively destroy the combination of gold and associated minerals, laying the foundation for improving mineral processing efficiency.
(2)New acid leaching technology
The new acid leaching technology significantly improves the leaching speed and recovery rate of gold by optimizing the ratio of acid and leaching conditions. For different types of oxidized gold ores, researchers can adjust the chemical composition of the acid to make it more targeted. For example, for some oxidized gold ores containing specific associated minerals, choosing the right acid ratio can dissolve these minerals more effectively, thereby releasing the encapsulated gold particles, making the leaching process more efficient and economical.
The above introduces the types of oxidized gold ores, the difficulties in mineral processing, the mineral processing process and innovative technical methods. In actual production, representative ore samples should be selected for mineral processing tests, and the mineral processing scheme and mineral processing process should be determined based on the test results.
