Analysis on the Application of Flotation Processes for Copper-Molybdenum Ores

Copper-molybdenum ore resources have unique structural properties, along with a series of significant drawbacks, such as low overall grade, scarce reserves of high-grade ores, an increasing proportion of low-grade and refractory ores, as well as a large variety of associated minerals with complex dissemination relationships in the ores. Based on these characteristics, flotation has become the main method for the beneficiation of copper-molybdenum ores. At present, the common flotation flowsheets for copper-molybdenum ores mainly include preferential flotation, semi-preferential-mixed flotation, and mixed flotation.

(1) Preferential Flotation

There are two specific methods for preferential flotation of copper-molybdenum ores: one is to float copper minerals first and then molybdenum minerals; the other is to float molybdenum minerals first and then copper minerals. This flowsheet is suitable for ores with relatively simple composition and significant differences in floatability between copper and molybdenum minerals. However, in industrial applications, both methods have a prominent problem - minerals after inhibition treatment are difficult to reactivate, which brings great difficulties to subsequent beneficiation operations. Therefore, preferential flotation is not widely used in actual concentrators.

(2) Semi-Preferential-Mixed Flotation

Semi-preferential-mixed flotation is applicable to copper-molybdenum ores with high feed grade. Its operation process is roughly as follows: first, reagents are used for short-term rapid flotation to separate out some easily floatable useful minerals; then, subsequent reagents are used for mixed flotation of the remaining minerals to recover other useful components; finally, according to actual production needs, the obtained concentrate is subjected to further flotation operations. A notable feature of this process is that it can achieve rapid recovery of useful minerals under the condition of relatively coarse grinding fineness, and at the same time, it can reduce the dosage of reagents, avoiding adverse effects of reagents on subsequent separation operations. However, semi-preferential-mixed flotation has relatively high requirements for equipment, which limits its application range to a certain extent.

(3) Mixed Flotation

Mixed flotation is usually used to treat copper-molybdenum ores with low feed grade. Its basic process is: first, collectors are added for preliminary flotation to separate copper and molybdenum minerals from gangue minerals, obtaining copper-molybdenum mixed concentrate; then, the mixed concentrate is subjected to flotation separation to finally obtain copper concentrate and molybdenum concentrate. Due to the good floatability of chalcopyrite and molybdenite in copper-molybdenum ores, good beneficiation effects can be achieved by adding sulfide mineral collectors such as xanthates and thionocarbamates in conventional flotation operations. However, mixed flotation also has obvious disadvantages: on the one hand, lime needs to be added as a regulator or depressant in the process, which will cause certain pollution to the environment; on the other hand, the use of lime will affect the desorption of collectors on the mineral surface in subsequent operations, bringing difficulties to copper-molybdenum separation.