In copper resources, except for independent oxidized copper deposits, most sulfide copper deposits have oxidation zones in the upper part. With the reduction of reserves of high-grade copper nickel sulfide ore, research on the beneficiation process of copper nickel oxide ore is gradually being carried out. Here, we mainly introduce the beneficiation process methods of copper nickel sulfide ore and copper nickel oxide ore.
In copper nickel sulfide ores, copper exists in the form of chalcopyrite, while nickel exists in the form of free nickel sulfide such as nickel pyrite, needle sulfide nickel ore, and purple sulfide nickel ore. A considerable portion of nickel exists in pyrrhotite as isomorphism. The commonly used beneficiation process is flotation, and there are three main flotation methods:
1. Priority flotation method
The priority flotation process is mainly aimed at ores with high copper content but low nickel content and simple properties. The priority flotation process of sulfide copper nickel ore usually adopts the process of "floating copper and suppressing nickel", which achieves the separation of copper and nickel by adding inhibitors of sulfide nickel minerals and efficient copper collectors.
The advantage of this process is that it can directly obtain copper concentrate with lower nickel content and qualified nickel concentrate, with lower cost; The disadvantage is that nickel pyrite and purple sulfide nickel ore, which are suppressed during copper flotation, are difficult to activate in subsequent flotation, resulting in low nickel recovery rate and waste of nickel resources.
2. Mixed flotation method
The mixed flotation of sulfide copper nickel ore is mostly suitable for selecting copper nickel ore with lower copper content than nickel content. The process method involves mixed flotation of copper and nickel minerals from the ore, and then selecting copper concentrate (containing low nickel) and nickel concentrate (containing low copper) from the mixed concentrate. The resulting nickel concentrate can be directly smelted.
3. Mixed priority flotation method
The mixed optimization flotation method involves first mixing copper and nickel minerals for flotation, and then selecting copper and nickel concentrates from the mixed concentrate. If there is a significant difference in the floatability of various nickel minerals, after mixed flotation of copper and nickel, the tailings can be re enriched to further recover nickel minerals with poor floatability.
It is worth noting that when determining the flotation process flow in this process method, a principle should be followed: it is better to allow copper to enter the nickel concentrate than to avoid nickel entering the copper concentrate, mainly because nickel in the copper concentrate loses a lot during the smelting process, and copper in the nickel concentrate can be effectively recovered.
A case study of a step flotation flotation tailings high intensity magnetic separation project:
The valuable metal elements that can be comprehensively recovered and utilized in this copper nickel ore include copper, nickel, cobalt, gold, and silver, with grades of 5.71%, 0.86%, 0.080%, 0.44g/t, and 51.39g/t, respectively. Copper nickel ore has a high oxidation rate, and clay minerals such as kaolinite and montmorillonite have a high content of iron oxide. The copper minerals in the ore are mainly malachite, blue copper ore, and silicon malachite, while the accompanying nickel and cobalt are mainly produced in the form of laterite nickel ore, making it a difficult to select copper nickel oxide ore.
The comprehensive recovery of copper, nickel, cobalt, gold, and silver is achieved through the process of "step-by-step flotation flotation strong magnetic separation of tailings". The closed circuit test obtained a copper sulfide concentrate with a copper grade of 28.52%, gold content of 2.68 g/t, silver content of 742.06 g/t, copper recovery rate of 13.08%, gold recovery rate of 16.05%, and silver recovery rate of 38.19%. The oxidized copper concentrate with a copper grade of 17.85%, gold content of 0.84 g/t, silver content of 107.20 g/t, copper recovery rate of 57.39%, gold recovery rate of 35.20%, and silver recovery rate of 38.68% was obtained. The total recovery rates of copper, gold, and silver are 70.47%, 51.25%, and 76.87%, respectively. Wet high intensity magnetic separation is used for flotation tailings to obtain high intensity magnetic concentrates containing 2.39% copper, 1.36% nickel, and 0.13% cobalt. The recovery rates of copper, nickel, and cobalt are 17.76%, 65.74%, and 66.70%, respectively. Metallurgical methods can be used to treat the high intensity magnetic concentrate to recover copper, nickel, and cobalt.
The above are commonly used beneficiation methods for copper nickel sulfide ore and copper nickel oxide ore. The development of beneficiation process methods in production should be based on the properties of the ore, conduct beneficiation experiments, and determine suitable process methods to obtain better beneficiation recovery rate and concentrate indicators.
