Copper-molybdenum ore is an important mineral resource for obtaining copper and molybdenum metals. Copper-molybdenum ore is generally produced in porphyry copper deposits and skarn copper deposits, especially porphyry copper deposits are always associated with molybdenite. While recovering copper sulfide, the comprehensive recovery of molybdenum should be considered. This article mainly introduces the characteristics of low-grade porphyry copper-molybdenum ore and the commonly used process flow for copper-molybdenum ore dressing.
In low-grade porphyry copper-molybdenum ore, the particle size of useful minerals is extremely uneven, the dissociation is poor, and the separation is difficult. The metal elements with recovery value in the original ore are mainly Cu and Mo, and the grade is low. The main metal minerals in the ore are chalcopyrite, molybdenite, pyrite, etc., and the main gangue minerals are quartz, feldspar, sericite, biotite, chlorite, etc.
The embedded particle size of molybdenite and chalcopyrite in the ore is uneven and fine. More than 90% of the embedded particle size of molybdenite is less than 0.08mm, of which molybdenite less than 0.02mm accounts for nearly 40%; the embedded particle size of chalcopyrite is slightly coarser than that of molybdenite, but it is still a fine-grained embedded type. About 80% of chalcopyrite is less than 0.08mm, of which chalcopyrite less than 0.02m accounts for 20%. Therefore, fine grinding technology should be adopted in the grinding stage.
The focus of copper-molybdenum ore beneficiation technology is copper-molybdenum separation. Common methods include preferential flotation and mixed flotation. Among them, mixed flotation is more commonly used. Generally, copper-molybdenum mixed concentrate is obtained first, and then a complex separation process is carried out.
1. Mixed flotation - mixed concentrate regrinding and concentration - flotation molybdenum suppression copper separation process
(1) Determine the grinding fineness
First, take representative ore samples for beneficiation test, and determine the grinding fineness through the test. The determination of grinding fineness should follow this principle: at this fineness, the grades of copper and molybdenum in the mixed concentrate do not change much, and the recovery rates both reach the upper limit; if the grinding fineness is further increased, the recovery rates of copper and molybdenum both show a downward trend.
(2) Copper-molybdenum mixed flotation
In the mixed flotation stage, the roughing collector usually selects a mixture of butyl xanthate and butyl ammonium black medicine. This combination can ensure that the copper-molybdenum mixed flotation achieves a better effect and obtains a higher grade mixed concentrate.
(3) Mixed concentrate regrinding and concentration
Experiments have shown that when the copper-molybdenum mixed concentrate is not regrinded, pyrite is difficult to be effectively suppressed and the grade of the copper-molybdenum ore is difficult to improve. Therefore, the copper-molybdenum mixed concentrate is regrinded. However, the grinding fineness should be determined by mineral processing tests to avoid grinding too finely, which may cause difficulty in molybdenum recovery. During the selection process, an appropriate amount of lime can be added to separate sulfur and copper.
(4) Copper-molybdenum separation flotation
The separation of copper and molybdenum is the key point and difficulty in copper-molybdenum ore selection. This flotation process can adopt a combination of roughing and selection. In terms of flotation reagents, the dispersion and inhibition effect of water glass alone on the pulp is poor, and it needs to be mixed with the other two reagents, and water glass and sodium hexametaphosphate are used together. In addition, adding kerosene in the copper-molybdenum separation flotation stage can effectively improve the molybdenum selection index.
2. Other mineral processing processes
(1) Fully mixed flotation process and partially mixed flotation process
Dexing Copper Mine Sizhou Concentrator: adopts a process of one-stage rough grinding-mixed flotation-rough concentrate regrinding-copper-molybdenum and sulfur separation-tailing sulfur selection-copper-molybdenum separation.
Inner Mongolia Wushan Ore Dressing Plant: adopts a process of coarse grinding - preferential flotation of copper and molybdenum against sulfur - sulfur selection of tailings (direct tailings discarding) - separation of copper and molybdenum from copper-molybdenum mixed concentrate.
(2) Partial rapid preferential flotation process
For example, the Dashan Concentrator of Dexing Copper Mine uses highly selective collectors to preferentially and rapidly float out molybdenum minerals and some copper minerals with fast flotation speeds, and then strengthens the recovery of copper minerals and sulfur minerals with slow flotation speeds. The copper-molybdenum mixed concentrate that is rapidly and preferentially selected is used for copper-molybdenum separation, and the copper-sulfur mixed concentrate is used for copper-sulfur separation. This process reduces the amount of copper minerals during copper-molybdenum separation and reduces the difficulty of copper-molybdenum separation.
