Study on Process Characteristics and Flotation Test of a Refractory Copper Oxide Ore

Yao copper oxide ores large complex nature having a high rate of oxidation, a high rate, a high content of Ca, Mg, containing a large quantity of mud, mineral and low index, is typically difficult Copper Oxide. A number of domestic research institutes have conducted a variety of methods of experimental research. The results of flotation experiments show that the flotation reagent consumption is large, the rough selection time is long, the medium ore is difficult to enrich, the flotation index is low, and the concentrate grade is 7 %~12%, the recovery rate is less than 65%; the results of the wet leaching test show that the leaching agent consumption is large, the solid-liquid separation is difficult, and the leaching rate is low. This experimental study starts from the mineralogical characteristics, finds out the reasons for the difficulty in selecting such ore, and selects the copper oxide ore activator D ₂ with the aim of winning, and formulates a reasonable flotation process, and obtains a satisfactory flotation index. .

I. Process mineralogy research

(1) Chemical composition of raw ore

The results of multi-element analysis of raw ore are shown in Table 1, and the results of copper phase analysis are shown in Table 2.

Table 1 Multi-element analysis results of raw ore

Table 2 Copper phase analysis results

(2) Mineral composition

The main mineral composition is shown in Table 3. The distribution of copper in the ore is shown in Table 4.

Table 3 Mineral distribution in ore

Table 4 Distribution of copper in ore

(3) Ore structure

The ore is light grayish green and grayish brown. There are mainly block structures, thin layer structures, and breccia structures.

Block structure: The ore is mainly composed of calcium and mud, and a small amount of quartz sand, etc., is a dense block, which constitutes a massive structure and is the main structure of the ore.

Thin layered structure: silty mudstone, calcareous mudstone, sandy calcareous mudstone, etc. are distributed in thin layers.

Breccia structure: local quartz crumb and feldspar crumb in the ore have a particle size greater than 2 mm and form breccia.

(4) Structure of the ore

Sand-like structure: The debris in the rock is about 50%-85%, and it is round and angular. The crumbs are often iron , calcium mud and microcrystalline muddy calcite and limonite.

Mud structure: The ore is mainly composed of calcium mud. Part of the mud recrystallized in the form of microscopic scales, some of which are distributed in the form of granular limonite or are inoculated with limonite.

Microcrystalline, fine-grained structure: The ore is mainly composed of microcrystalline and fine-grained calcite, with a small amount of mud and debris distributed in the middle.

(5) Main purpose minerals and embedding characteristics

After light sheet identification, artificial heavy sand identification, X-ray diffraction analysis and electron microscopy analysis, the main copper minerals were malachite, fibrinite, and a small amount of chalcopyrite and chalcopyrite. The main gangue minerals as quartz, calcite, dolomite, white mica, chlorite, anorthoclase like.

Malachite: It is the main copper mineral and target mineral in the ore. There are three distribution forms: one is distributed in calcium mud, calcium and mud, often in its shape, usually wrapped in muddy or calcium or iron. The quality is not high, the crystal is turbid, and the particle size is fine, ranging from 0.01 to 0.2 mm. The second is distributed in the debris. The third is distributed in the microcrystalline calcite, which is self-shaped.

Fibrous copper-copper ore: distributed in the form of fibers and fine particles, or wrapped in calcium mud, or wrapped in calcium mud, or dispersed in calcium mud, with a large change in particle size, generally in the range of 0.005 to 0.3 mm. .

(6) Discussion on mineralogical characteristics

1. The main copper minerals in the ore are malachite and fibrinite. The copper grade in the ore is 1.61%, of which copper sulfide accounts for 26.09%, oxidation rate is 73.91%, copper is combined with 38.51%, and free copper oxide is 35.40%. The typical refractory copper oxide ore is also one of the main reasons for the low flotation index. Theoretically recoverable copper is only 61.49%.

2. The malachite formed in the early stage is not pure, often wrapped in calcium mud, or wrapped in calcium mud, the particle size changes greatly, and the fine particles are disseminated in the calcium mud, resulting in a decrease in the floating activity of this part of malachite. The flotation concentrate has a large amount of mud, and the concentrate grade is not easy to increase.

3. The existence of the fiber silicon copper ore was first identified. It can be seen from the embedding characteristics and distribution of the silica-silica ore that the grain size of the partially-silica-copper ore and the gangue is extremely fine, and fine grinding is required to dissociate the monomer. Copper in the silico-copper ore accounts for 33.8% of the total copper in the ore, which is another major reason for the low flotation index.

4, the ore contains large amounts of alkaline earth metal carbonate, magnesium oxide, magnesium hydroxide, silicates and clay, silica fibers embedded copper fine particle size distribution, chemical leaching is the main reason for the low index.

Second, flotation test research

(1) Determination of the process

Considering that the content of copper sulfide minerals in the comprehensive ore samples is not much, and the copper sulfide minerals have been altered, in order to simplify the process, with reference to the experience of similar ore processing, it is decided to adopt the principle flow of oxygen and sulfur mixed flotation.

(2) Influence of grinding fineness on flotation index

The grinding fineness condition test process is that after the ore is ground, the flotation agent is added in turn, and flotation is carried out for 8 minutes to obtain coarse concentrate and tailings. The dosage and dosage were: water glass 500g/t, D ₂ activator l000g/t, Y xanthate 1500g/t, and pine alcohol oil 150g/t. The results of flotation test showed that when the grinding fineness was -74μm and 85%, the tailings grade was the lowest and the recovery rate was the highest.

The effect of grinding fineness on concentrate grade and recovery is shown in Figure 1.

Figure 1 Effect of grinding fineness on concentrate grade and recovery rate

1 recovery rate; 2 concentrate grade; the same below

(3) Selection of collectors and effects on flotation indicators

Under the condition that the fineness of grinding is -74μm and 85%, the process of flotation of the flotation agent and the dosage are tested by a rough selection and one sweeping process. xanthate, ethyl xanthate, Y xanthate xanthate and experiment with various ratios, but also study were tested as kerosine, diesel oil, hydroxy acids and other various auxiliary collector, found that most of the drug Reducing the grade of tailings has no obvious effect. On the contrary, the addition of some chemicals may cause a large amount of fine mud to float and deteriorate the flotation process. Some agents have some effect on flotation, but because the cost of the drug is too high, the main metal is considered comprehensively. And the recovery of associated silver , Y yellow drug is used as the collector, 1700g/t is added by rough selection, and 600g/t is added by sweeping. The effect of Y xanthate on concentrate grade and recovery is shown in Figure 2.

Figure 2 Effect of Y yellow medicinal amount on concentrate grade and recovery rate

(4) Selection of modifiers and effects on flotation indicators

In determining the grinding fineness and collector type and dosage, the process is carried out using the same lime, ethylenediamine phosphate, sodium silicate, sodium hexametaphosphate, sodium sulfide, D _2, EDTA, etc. In the experimental study, ethylenediamine phosphate has a certain effect on reducing the copper tailings grade, but it is not used due to the price and market source; water glass has a certain effect on dispersing the slime and improving the concentrate grade; in the test, as Compared with D ₂ used in the activator, the addition of D ₂ in the rough selection operation can significantly improve the recovery rate of copper and the concentrate grade. The addition of sodium sulfide not only causes a large amount of fine mud to float, but also a large amount of medium ore circulation. The ore grade is low, and due to the large amount of sodium sulfide, the pH of the slurry will increase, which is disadvantageous to the flotation of copper sulfide ore. The effect of D ₂ dosage on concentrate grade and recovery is shown in Figure 3. The effect of water glass dosage on concentrate grade and recovery is shown in Figure 4. Therefore, it was finally determined that 1300 g/t D _{2 was added} as an activator of copper oxide ore and 1000 g/t of water glass as a slime dispersant.

Figure 3 Effect of D ₂ activator dosage on concentrate grade and recovery

Figure 4 Effect of water glass dosage on concentrate grade and recovery rate

(V) Fully open flotation test process and indicators

The full open circuit (two selected) test process is shown in Figure 5, and the indicators are shown in Table 5.

Figure 5 Closed (open circuit) test process and conditions

Table 5 Full open circuit test indicators

(6) Closed circuit flotation test process and indicators

The closed-circuit test process and conditions are shown in Figure 5, and the indicators are shown in Table 6.

Table 6 Closed-circuit test indicators

As can be seen from Table 6, the copper grade of the concentrate is 21.12%, and the recovery rate is 61.29%. The associated metallic silver has also been well recovered.

1. The effect of the number of selections: The results of the open circuit test show that the selected grades can reach 24% in the selected two times; in the closed circuit test, the selected foam is sticky and the selection efficiency is low due to the influence of the return of the middle mine. In the closed circuit test, the influence of the number of selections on the selection index was examined. During the closed-circuit test, it was found that when the selection was twice, not only the selected grades were not high, but also the recovery rate could not be improved; adding a selection could significantly improve the concentrate grade under the premise that the recovery rate was not affected. Make sure to use three selected jobs.

2. The effect of pharmaceuticals on the recovery of mines: According to the literature, the addition of kerosene, diesel and other chemicals can reduce the secondary shedding of metals in the middle ore and increase the recovery of metals. This test carried out a special investigation. Whether it is the flotation or return of the middle ore mine, whether it is the addition of the agent to the rough selection or the flotation operation of the medium ore, the addition of kerosene and other chemicals has no significant improvement on the flotation index of the ore sample.

3. The impact of the return location of the middle mine: First, the middle mine (selected I tank and the selected I foam) returned to the rough selection, and the second was the return of the ball to the ball mill. The test results showed that the mine returned to the ball mill and regrind, which was obvious. Improve metal recovery rate. It is determined that the medium ore return ball mill is used to carry out the medium ore regrind process.

Third, the conclusion

(1) The ore is characterized by high oxidation rate, high bonding rate, high calcium and magnesium content and large mud content, which is a typical refractory copper oxide ore.

(II) For the first time, this study has identified the existence of a large amount of ore medium-fibrous silicon-copper ore, which is another major reason for the low ore dressing index of this type of ore.

(3) The process defined in this experiment is simple in structure, the chemical system is reasonable, and the theoretically recoverable metal has been completely recovered, and satisfactory technical indicators have been obtained.

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