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Study on New Process for Improving Copper Beading Index of Copper Oxide Iron Ore
New Technology for copper oxide, copper iron ore improved metallurgical performance
Wu Xiqun
Abstract: The ore dressing index of a copper oxide iron ore has been low. The copper grade of copper concentrate is 12%-16%, and the copper recovery rate is 55%-65%. The test uses a new process of copper sulfide and copper oxide distribution flotation and copper oxide flotation mineral leaching, which can greatly improve the copper index. Compared with the production process, the copper grade of copper concentrate is increased by 5%, and the total copper recovery rate is increased by more than 20%.
Key words: copper oxide; distributed flotation; medium ore; leaching
China's copper oxide ore reserves are relatively abundant and are an important part of China's copper resources. Reasonable development and utilization of copper oxide ore is of great significance for alleviating the contradiction between supply and demand of copper in China.
A copper-iron ore is a large skarn deposit that contains copper oxide in addition to primary copper. Although the copper oxide ore has a copper content of 2%, the production index has been very low, the copper concentrate grade is only 12% to 16%, and the copper recovery rate is 55% to 65%. Tests have shown that the use of conditioning agent B 10 , vulcanizing agent sodium sulfide and butyl xanthate + DY combination collector , the use of copper sulfide and copper oxide distribution flotation, copper oxide flotation section of the production of mineral leaching - In the new process, the flotation section can obtain copper concentrate with copper content of 21.14% and copper recovery rate of 74.27%. For medium-grade acid leaching with a yield of 12.87%, the copper leaching rate is 86.50%, which can be recovered for raw ore. 13.37% of copper, plus copper recovered by flotation, the total recovery of copper is 87.57%. Compared with the on-site production process, the copper concentrate grade is increased by 5% and the total copper recovery rate is increased by more than 20%.
1 ore nature
Metallic ore minerals are minerals iron and copper minerals. Copper minerals are mainly composed of copper oxide minerals such as malachite, pseudo malachite, cuprite, and cuprous iron ore. In addition, a small amount of copper sulfide ore such as chalcopyrite, copper blue, chalcopyrite and natural copper is also contained. Object. Iron minerals are mainly magnetite, semi-artificial hematite, imaginary hematite, limonite and the like.
The gangue minerals are mainly quartz , chalcedony, opal and clay minerals such as kaolinite and montmorillonite. For copper oxide ore containing clay minerals, the sorting is more difficult.
The chalcopyrite and the chalcopyrite are irregularly granulated in the cracks and particle gaps of magnetite and hematite, and the inlaid grain size is 0.02-0.15 mm. Most of the malachite is gelatinously distributed in the fractures of iron minerals. The gelatinous malachite is densely packed with a grain size of 0.02-0.15 mm. A small number of small star-shaped dots are filled in the pores of iron oxide minerals, and iron ore. The relationship is very close. Natural copper is distributed in the fissures of limonite and hematite, and the inlaid grain size is 0.02-0.08 mm. Pseudo-malachite is embedded in iron mineral fractures or holes in the form of single mineral aggregates, generally dense blocks, layers, etc., closely related to malachite.
The main element content (%) in the ore is: Cu2.31, Fe48.40, S0.50/Au1.27g/t, Ag12.0g/t, SiO 2 14.24, CaO0.28. The copper oxidation rate was 85.13%.
When the ore milled to -74μm accounted for 70%, the results of sieve water analysis showed that the yield of -20μm was 15.81%, the grade of copper was 4.14%, and the distribution of copper accounted for 28.75%.
2 test plan selection
For the treatment of the copper oxide ore, the on-site production process is the first selection of gold, the gold tailings segmented vulcanization flotation copper oxide, the copper concentrate, the copper sulfide tailings are re-sweeped, and the selected foam is selected. The concentrate obtained afterwards is combined with the concentrate obtained by copper sulfide. The problem in production is that the copper concentrate grade is low (12% to 16%) and the copper recovery rate is not high (55% to 65%). In response to this situation, many units in China have conducted a lot of research [1] . It is treated by a single flotation method. Due to the high content of oxidized ore and the poor selectivity of the collector, the selection index has not been satisfactory. Treated by a single hydrometallurgical process, some of the copper sulfide in the ore is lost to the leaching residue. The use of raw ore mud sand classification, slime wet leaching, ore flotation scheme, the amount of desilted coal is difficult to improve the ore flotation index; when the amount of mud removal is large, although the ore flotation index is improved, the acid consumption is large, and the sludge is entered. The copper sulfide loss is also large. Many researchers have conducted key researches on the treatment of slime, such as “sodium oxysulfate flotation de-sludge, mud-sand separation†and “sludge-sand separation process [2] â€. These methods are characterized by effective use. The collector first floats out of the slime, and then the mud and sand are separately floated, and the selection index is improved. Some scholars have also proposed direct sulfide flotation of raw ore. Although the copper grade of copper concentrate can be improved, the copper recovery rate is still low. There is also a mechanical method to remove the slime. Then, in the mud-sand sorting process, there is also a problem that the comprehensive index is not high. In addition, the slime is also treated by acid leaching-precipitation flotation, acid leaching-precipitation-carrier flotation, acid leaching-filtration-electrowinning, acid leaching-extraction-electrowinning, and some of the schemes have also been obtained. Good results, but these schemes are based on acid leaching, which has a large yield and high acid consumption, which makes the cost too high to be used in production.
On the basis of summarizing the past research work, this experiment focuses on improving the process from a new perspective, in order to improve the copper selection index.
After the original ore grinding to -74μm accounted for 70%, after three-stage flotation (ie direct flotation), the obtained crude concentrate contains 9.78% copper and the copper recovery rate is 86.79%. Under the same grinding fineness, the ore is graded by 20μm particle size, and then the mud and sand are separately subjected to three-stage flotation, and the two crude concentrates are combined to contain 9.72% of copper. The copper recovery was 87.16%. The copper grade and recovery rate of the coarse concentrate obtained by the two schemes are very close. It can be seen that the classification of the original ore mud sand does not have much superiority.
The yield of -20 μm slime from the ore was 15.81%, and the copper grade was 4.14%. The copper occupation rate is 28.75%. Under normal temperature and pressure, after leaching with sulfuric acid for 4h, the leaching residue contains 0.68% copper and the copper leaching rate is 84.30%.
The tailings directly flotation of the ore is re-swept, and the obtained foam product has a copper grade of 2.75%. Under normal temperature and normal pressure, the sulfuric acid is immersed for 3 hours, the leaching slag contains 0.37% of copper, and the copper leaching rate is 86.93%.
The leaching rate of acid mud leaching and sweeping foam acid leaching is similar. Considering that it is necessary to increase the mud removal operation to remove the slime, the operation difficulty in production should be increased, so it is not suitable to use the slime leaching scheme.
From the above test results, the main process should use direct flotation of raw ore, on the basis of which the possibility of leaching of the middle ore produced by the flotation section is further studied. Based on this, a new process plan for selection and smelting was proposed.
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3 selection - new technology research
There are many kinds of copper minerals in copper oxide ore. There are a large amount of copper oxide and a small amount of copper sulfide. However, the floatability between copper sulfide minerals and copper oxide minerals is quite different, so the first copper sulfide can be used. A step-by-step flotation process for re-floating copper oxide.
3.1 copper sulfide flotation
Copper sulfide is floated with butyl xanthate, butylammonium black and pine oil. Featured flotation rougher concentrate water glass or sodium hexametaphosphate dispersing sludge and the phosphorus-containing iron sludge inhibition, copper sulfide can be improved selectivity sorting operations, and improve the copper recovery operation. The flotation of copper sulphide is relatively simple and will not be repeated here.
3.2 copper oxide flotation
The flotation of copper oxide is the focus of this study. Whether the regulator, vulcanizing agent and collector and the process structure are reasonable are the main factors affecting the flotation index of copper oxide ore.
3.2.1 Effect of regulator B 10 on the selection
Multi-oxidized ore containing mud, resulting in a low index sorting operation, in order to reduce interference to the sludge separation operations discussed sodium hexametaphosphate, sodium silicate effect, B 10, such as humic acid sodium agents to the B 10 The sorting effect is better. The effect of B 10 on the copper grade and recovery of flotation coarse concentrate is shown in Figure 1. The results show that with the increase of B 10 dosage, the copper grade of copper coarse concentrate is obviously increased, and the copper recovery rate is also improved. It can be seen that B 10 has obvious effect on dispersing slime and inhibiting gangue.
Figure 1 B 10 impact on rough selection indicators
1—copper grade; 2—copper recovery
3.2.2 Effect of sodium sulfide
Research and shows that sodium sulfide is the main vulcanizing agent for copper oxide minerals [1] . Sodium sulfide reacts with copper oxide minerals to form a copper sulfide film on the surface of the mineral, thereby enhancing the hydrophobicity of the mineral surface and increasing the adsorption rate of the collector. The effect of sodium sulfide on the copper index of flotation coarse concentrate is shown in Fig. 2. It can be seen from the figure that as the amount of sodium sulfide increases, the copper grade decreases, while the copper recovery rate increases, but the amount of sodium sulfide is too large. The recovery rate has decreased, because the excess sodium sulfide will inhibit the sulfided copper oxide. In order to prevent or mitigate this effect, the amount of sodium sulfide should be strictly controlled and a stepwise dosing method should be adopted.
Figure 2 Effect of sodium sulfide on coarse selection index
1—copper grade; 2—copper recovery
3.2.3 Collector selection
The key to increasing copper recovery is to increase the recovery of copper oxide minerals. Choosing an effective collector is one way to increase copper recovery. Tested on sodium sulfonate, hydroxamic acid, bisphosphonate, sodium lauryl sulfate, butyl xanthate, isobutyl xanthate, DY and their mixed use, in which DY and butyl xanthate were mixed. better. The test results of several better-performing agents are shown in Table 1. The results show that the combination of butyl xanthate and DY can improve the copper grade and recovery of coarse concentrate. Therefore, butyl xanthate is used in combination with DY.
Table 1 Collector test results /%
Collector
product name
Yield
Copper grade
Copper recovery
Isobutyl xanthate
DY
Coarse concentrate
Tailings
Raw ore
25.43
74.57
100.0
8.00
0.35
2.30
88.63
11.37
100.0
Butyl xanthate
DY
Coarse concentrate
Tailings
Raw ore
25.03
74.97
100.0
8.14
0.31
2.29
89.74
10.26
100.0
Butyl xanthate
Coarse concentrate
Tailings
Raw ore
21.40
78.60
100.0
7.85
0.68
2.22
75.87
24.13
100.0
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3.2.4 Copper oxide selection
Copper oxide is mainly flocculated by vulcanization, but in the process of selection, the copper mineral in the coarse concentrate easily enters the selected tailings, resulting in low recovery rate of copper in the selected operation. In order to improve the selection effect, the coarse essence is discussed. The mine and the sweeping foam are treated separately.
(1) Selection of coarse concentrates. The coarse concentrate obtained by flotation of copper oxide is added with sodium sulfide at the time of selection, and the influence of sodium sulfide on the selection is shown in Fig. 3. The selective addition of sodium sulfide improves the copper recovery of copper oxide selection operations.
(2) Select the foam selection. The sweeping foam contains 3.65% copper, and the sodium concentrate obtained by adding sodium sulfide is only 7%, and the recovery rate is only 60%. It can be seen that the sweeping foam product is not suitable for treatment by flotation method, and rational treatment of this part of the product is the key to improving the total copper recovery rate.
Figure 3 Effect of sodium sulfide on the selection of copper oxide
1—copper grade; 2—copper recovery
3.3 mineral acid leaching test
Copper oxide coarse concentrate selected tailings and copper oxide sweeping foam are combined into medium mine. At normal temperature, the medium ore is leached with sulfuric acid. The effect of sulfuric acid on copper leaching rate of leaching operation is shown in Figure 4 under the conditions of liquid-solid ratio of 2:1 and leaching time of 3 h. As the amount of sulfuric acid increases, the copper leaching rate of the leaching operation increases.
Figure 4 Effect of sulfuric acid on the leaching rate of flotation mine
3.4 Test procedures and indicators
According to the characteristics of ore and conditional tests, the selection and smelting process of acid leaching using preferential flotation of copper sulfide, subsequent vulcanization of flotation of copper oxide with sodium sulfide, copper oxide tailings and sweeping foam combination (ie, medium ore) Treatment of copper oxide ore. In order to prevent the sludge from deteriorating the flotation process of copper oxide, a high-grade copper oxide concentrate is obtained, and the copper oxide coarse concentrate is selected as an open circuit. The new process flow is shown in Figure 5, and the test results are shown in Table 2.
Figure 5 Selecting the new process
Table 2 Closed circuit test results /%
product name
Yield
Copper grade
Copper recovery
Copper sulfide concentrate
Copper oxide concentrate
Total copper concentrate
Infusion
Leaching
Middle mine
Tailings
Raw ore
1.11
6.94
8.05
12.87
79.08
100.0
17.35
21.75
21.14
5.234g/L
0.37
2.74
0.30
2.29
8.41
65.86
74.27
13.37
2.00
15.37
10.36
100.0
The flotation process of sulfur copper and copper oxide is used. The copper concentrate contains 21.14% copper and the copper recovery rate is 74.27%. The ore mining yield is 12.87%. The acid leaching can reduce the copper content of the leaching residue to 0.37%, and the copper working leaching rate reaches 86.97%. For the original ore, the recovery rate can be increased by 13.37%. The flotation and acid-leaching copper-containing solution can be recovered by a mature extraction-electrowinning process.
3.5 Estimation of economic benefits
Under the premise of increasing the copper recovery rate of flotation, the medium-mineral acid leaching can increase the copper recovery rate by 13.37%, and the production rate of 85% can increase the copper recovery rate by 11.36%. The copper leaching solution is calculated by the extraction-electrowinning process to produce copper. The recovery rate is 96%. Then the leaching-extraction-electrowinning process can increase the copper recovery rate by 10.91%.
For the production series of copper oxide ore with a treatment capacity of 1000t/d, the annual increase of copper is
1000t/d×300d×2.29%×10.91%=749.517t
Taking the leaching-extraction-electrowinning process, the cost per 1t of copper produced is about 10,000 yuan, and the price per t-electric copper is 25,000 yuan, the annual economic benefit is
749.517×(25,000 yuan/t-110,000 yuan/t)=1124.28 million yuan
Using the leaching-extraction-electrowinning process, the investment for producing 1t of copper is 10,000 yuan, and the total investment of 749.517t of copper is 749.517 million yuan.
It can be seen that the payback period of the investment in the selection process is
749.517 million yuan (112.224 million yuan / year ÷ 300 days) = 200 days
Investment can be recovered in less than 7 months. If the benefits of the upper flotation are calculated again, the benefits are more significant.
4 Conclusion
The copper oxide ore has a high mud content and is easily muddy during the grinding process, which causes the flotation process to deteriorate and it is difficult to obtain a satisfactory sorting index. The new flotation agent, and the new process of acid flotation after copper sulfide and copper oxide flotation, copper oxide tailings and sweeping foam can greatly improve the copper grade and recovery rate in copper concentrate. Significant economic benefits. This new process is an effective method for handling such copper oxide ore.
references
1 Zhang Wenbin. Research and Practice of Copper Oxide Ore Flotation. Changsha: Central South University of Technology Press. 1992
2 Li Bingqiu. Study on the flotation process of copper oxide ore. Non-ferrous metals (elite processing). 1982. (6): 56