A serpentine inhibitor and its use in the flotation of copper and nickel from copper-nickel ore

Abstract

This invention discloses a serpentine inhibitor and its application in the flotation of copper and nickel in copper-nickel ore. The serpentine inhibitor is nanocellulose. The specific application includes the following steps: copper-nickel ore is ground using a ball mill, then adjusted into a slurry. Nanocellulose is added to the slurry and stirred. Subsequently, ethyl xanthate and No. 2 oil are added sequentially and stirred. After 1-2 roughing stages, 2-3 scavenging stages, and 2-3 cleaning stages, a copper-nickel concentrate is obtained. The serpentine inhibitor nanocellulose in this invention has a wide range of raw material sources, is environmentally friendly, contains no phosphorus, has a high copper-nickel metal recovery rate, and a low magnesium oxide content in the concentrate, enabling efficient enrichment of pyrite and chalcopyrite in copper-nickel ore.

Description

Technical Field

[0001] This invention belongs to the field of metal mineral processing technology, and relates to a serpentine inhibitor and its application in the flotation of copper and nickel in copper-nickel ore. Background Technology

[0002] With the continuous development and utilization of nickel ore resources, the amount of directly usable high-grade ore is decreasing. Many low-grade pyrite ore resources contain a large amount of fine-grained serpentine, making their development and processing increasingly difficult. Serpentine is a common gangue mineral in nickel deposits, and unlike pyrite, its surface is often positively charged. During flotation, due to electrostatic effects, serpentine easily adsorbs and coats the surface of pyrite, thus hindering the adsorption of collectors on the pyrite surface, reducing the recovery rate and grade of pyrite in the flotation product, resulting in excessively high magnesium oxide content in the copper-nickel ore concentrate, and deteriorating the smelting process. Current technologies for flotation of copper-nickel ore containing serpentine generally utilize sodium hexametaphosphate, water glass, carboxymethyl cellulose, etc., as serpentine depressants to achieve the separation of serpentine and pyrite. However, phosphorus-containing inhibitors such as sodium hexametaphosphate can easily cause eutrophication of water bodies; water glass and carboxymethyl cellulose have limited effects on fine serpentine particles, and large dosages cannot solve the entrainment problem during flotation. In addition, the synthesis of water glass requires the use of soda ash, and the raw material source is not environmentally friendly. There is an urgent need for a highly efficient and environmentally friendly serpentine inhibitor. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a serpentine inhibitor and its application in the flotation of copper and nickel ore. The serpentine inhibitor of this invention can selectively inhibit serpentine, promoting efficient separation of serpentine and copper-nickel ore, improving the recovery rate of copper and nickel metal, and reducing the magnesium oxide content in the copper-nickel concentrate.

[0004] The serpentine inhibitor provided by this invention is nanocellulose, which has at least one of the hydrophilic groups hydroxyl, sulfonic acid, and carboxyl groups on its surface; the nanocellulose is a monodisperse particle with a diameter of 20-200 nm and a length of 50-1000 nm; in the flotation of copper-nickel ore, the nanocellulose can selectively inhibit serpentine in copper-nickel ore, thereby separating serpentine from copper-nickel ore; the nanocellulose also has a flocculation effect, enabling fine serpentine particles to flocculate.

[0005] The application of this serpentine inhibitor in the flotation of copper and nickel ore provided by the present invention includes the following steps:

[0006] 1) Grinding: Grinding the raw copper-nickel ore and then preparing it into a slurry;

[0007] 2) Flotation: First, add nanocellulose to the slurry from step 1) and stir, then add ethyl xanthate and stir, then add No. 2 oil and stir to carry out flotation of chalcopyrite and nickel pyrite to obtain a copper-nickel mixed concentrate.

[0008] Preferably, in step 1), the copper-nickel ore is ground to a fineness of -74μm, accounting for 60% to 85%.

[0009] Preferably, in step 2), flotation includes roughing, sweeping, and cleaning.

[0010] Further preferably, in step 2), the flotation includes 1 to 2 roughing flotations, 2 to 3 sweeping flotations, and 2 to 3 cleaning flotations.

[0011] Preferably, in step 2), the stirring time for adding nanocellulose to the slurry is 2-6 minutes, the stirring time for adding ethyl xanthate to the slurry is 2-6 minutes, and the stirring time for adding No. 2 oil to the slurry is 2-6 minutes.

[0012] Preferably, in step 2), the amount of nanocellulose added is 100-2000 g / t relative to the copper-nickel ore.

[0013] The principle of this invention:

[0014] In copper-nickel ore, both pyrite and chalcopyrite have negatively charged surfaces, while serpentine has a positively charged surface. Fine-grained serpentine coats the surfaces of pyrite and chalcopyrite through electrostatic attraction, making these surfaces hydrophilic. This reduces the copper-nickel metal recovery rate in the concentrate and increases the serpentine content. Nanocellulose has one or more of hydroxyl, sulfonic acid, and carboxyl groups on its surface, resulting in a large negative charge. Adding negatively charged nanocellulose (such as...) to the slurry... Figure 1 As shown in the diagram, nanocellulose is adsorbed onto the surface of serpentine through electrostatic attraction, changing the surface charge of serpentine to negative. Therefore, serpentine will no longer coat the surfaces of pyrite and chalcopyrite. The long fibrous structure of nanocellulose can cause serpentine flocculation, increasing the apparent particle size of serpentine and significantly reducing the risk of fine serpentine particles being carried into the concentrate by flotation foam. Simultaneously, because nanocellulose carries a large amount of negative charge, it will not adsorb onto the surfaces of pyrite and chalcopyrite, thus having almost no inhibitory effect on copper and nickel. This invention, by adding nanocellulose, can improve the recovery rate of copper and nickel metals and reduce the magnesium oxide content in copper-nickel concentrate.

[0015] The beneficial effects of this invention are:

[0016] This invention employs nanocellulose as a serpentine depressant in the copper-nickel ore flotation process. It selectively inhibits serpentine, promoting efficient separation of serpentine and copper-nickel ore. Furthermore, nanocellulose exhibits flocculation properties, causing fine serpentine particles to flocculate and reducing foam entrainment. The nanocellulose raw material is derived from natural plant pulp fibers, prepared via hydrolysis. The raw materials are widely available and inexpensive, resulting in significant social, environmental, and economic benefits. The use of nanocellulose to inhibit serpentine flotation in the copper-nickel ore flotation process not only improves the recovery rate of copper-nickel ore but also enhances the quality of the copper-nickel ore concentrate, reduces the magnesium oxide content in the concentrate, and simultaneously stabilizes the flotation process, making wastewater treatment easier. Attached Figure Description

[0017] Figure 1 A comparison diagram of the electrical properties of nanocellulose and serpentine.

[0018] Figure 2 This is a flotation flowchart for Example 1.

[0019] Figure 3 This is a flotation flowchart for Example 3. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0022] To more clearly demonstrate the technical effects of the technical solution provided by the present invention, the copper-nickel ore flotation method and nanocellulose inhibitor provided by the present invention will be described in detail below with specific embodiments.

[0023] Example 1

[0024] The copper-nickel ore used in this embodiment mainly contains nickel pyrite and chalcopyrite, with a nickel grade of 0.76% and a copper grade of 0.29%. The gangue minerals are mainly serpentine and magnetite.

[0025] The nanocellulose used in this embodiment is synthesized according to existing technology, and will not be described in detail here.

[0026] The nanocellulose used in this embodiment has sulfonic acid groups on its surface.

[0027] according to Figure 2 The process shown involves flotation of the aforementioned copper-nickel ore, including the following steps:

[0028] (1) Grind the raw ore to a fineness of -0.074mm, accounting for 85%, and then adjust it into a slurry;

[0029] (2) Add 500g / t of serpentine inhibitor nanocellulose, 200g / t of ethyl xanthate and 15g / t of No. 2 oil to the slurry for roughing operation to obtain foam products and bottom products;

[0030] (3) Add nanocellulose to the foam product for three rounds of fine selection. The specific reagent system is as follows: add 200g / t of nanocellulose in the first fine selection, add 100g / t of nanocellulose in the second fine selection, and do not add reagents in the third fine selection; after the three fine selections, the concentrate is obtained.

[0031] (4) The bottom product of the tank was scavenged three times to obtain tailings. The flotation results are shown in Table 1.

[0032] Example 2

[0033] This embodiment is basically the same as Example 1, except for the nanocellulose. The nanocellulose used in this embodiment has carboxyl groups on its surface. The nanocellulose in this embodiment is also synthesized according to existing technology, and will not be described in detail here.

[0034] Example 3

[0035] The main useful minerals in the copper-nickel ore used in this embodiment are pyrite and chalcopyrite, with a nickel grade of 0.94% and a copper grade of 0.34%. The gangue minerals are mainly serpentine, magnetite, pyrite, chlorite, calcite, etc.

[0036] This embodiment uses the same nanocellulose as in Example 1.

[0037] According to Figure 3 The process shown is as follows for the flotation of the aforementioned copper-nickel ore:

[0038] (1) Grind the raw ore to a fineness of -0.074mm accounting for 75%, and then adjust it into a slurry;

[0039] (2) Add 1500g / t of serpentine inhibitor nanocellulose, 300g / t of ethyl xanthate and 20g / t of No. 2 oil to the slurry for roughing operation to obtain foam products and bottom products;

[0040] (3) The foam product is refined three times. The reagent system for the three refinements is as follows: 400g / t of nanocellulose is added in the first refinement, 100g / t of nanocellulose is added in the second refinement, and no reagent is added in the third refinement; after the three refinements, the concentrate is obtained.

[0041] (4) The tailings are obtained by scavenging the bottom product three times.

[0042] The flotation results are shown in Table 1.

[0043] Comparative Examples 1-4

[0044] The copper-nickel ore used in Comparative Examples 1-4 was the same as that used in Example 1. The depressants used in the flotation tests were commonly used reagents, as detailed below:

[0045] Comparative Example 1: No serpentine inhibitor was added, and the other steps were the same as in Example 1.

[0046] Comparative Example 2: 2000 g / t water glass was used as a serpentine inhibitor, and the other steps were the same as in Example 1.

[0047] Comparative Example 3: 800 g / t carboxymethyl cellulose (CMC) was used as a serpentine inhibitor, and the other steps were the same as in Example 1.

[0048] Comparative Example 4: 2000 g / t sodium hexametaphosphate was used as the serpentine inhibitor, and the other steps were the same as in Example 1.

[0049] The above are the optimal conditions selected after optimization of the experimental conditions.

[0050] The flotation results are shown in Table 1.

[0051] Table 1. Flotation results using different serpentine inhibitors

[0052]

[0053] Note: The raw ore grade values ​​in Examples 1-2 and Comparative Examples 1-4 in the table are derived from the test results of the products. Errors are unavoidable during the test process, but these errors are within the national standard range.

[0054] As shown in Table 1, the MgO content in the concentrates of Examples 1, 2, and 3 is all below 6.5%, meeting the requirements for magnesium oxide content in concentrates. Furthermore, the grades and recoveries of nickel and copper are at relatively high levels. Due to differences in ore properties among different deposits, there are some differences in the nickel and copper recoveries in the concentrates of Examples 1 and 3, but all meet the requirements for actual production. This also indicates that carboxyl-based and sulfonic acid-based nanocellulose have a strong inhibitory effect on magnesium oxide, but a weak inhibitory effect on pyrite and chalcopyrite. Compared with Comparative Example 1, the copper grade in the concentrate obtained in Example 1 increased by 0.32 percentage points, the nickel grade increased by 1.01 percentage points, and the magnesium oxide content decreased by 6.3 percentage points, while the copper and nickel recoveries remained almost unchanged. In contrast, the concentrate obtained using water glass in Comparative Example 2 had a copper recovery rate that decreased by 1.11 percentage points and a nickel recovery rate that decreased by 0.62 percentage points compared to Example 1, while the magnesium oxide content increased by 2.64 percentage points. This indicates that water glass has a poor inhibitory effect on magnesium oxide, resulting in a higher magnesium oxide content in the concentrate, failing to meet the required magnesium oxide content of 6.5%. The results of Comparative Example 3 show that the copper recovery rate in the concentrate obtained using CMC decreased by 3.84 percentage points and the nickel recovery rate decreased by 3.49 percentage points compared to Example 1, indicating that CMC had a strong inhibitory effect on nickel pyrite and chalcopyrite. The results of Comparative Example 4 show that the concentrate grade obtained using sodium hexametaphosphate was comparable to that of Example 1, and the magnesium oxide content in the concentrate was also comparable, indicating that nanocellulose has a similar effect to the widely used sodium hexametaphosphate. However, sodium hexametaphosphate has a higher phosphorus content, which can easily lead to eutrophication of water bodies; therefore, using nanocellulose is more environmentally friendly.

[0055] In summary, the serpentine inhibitor nanocellulose used in this invention can achieve efficient enrichment of pyrite and chalcopyrite, and reduce the magnesium oxide content in the concentrate. Pyrite and chalcopyrite in copper-nickel ores carry a negative charge, while the magnesium oxide-rich fine-grained serpentine carries a positive charge. Using inorganic inhibitors such as water glass requires very high dosages to disperse serpentine, and still cannot solve the problem of mechanical entrainment. The nanocellulose used in this invention, carrying a large amount of negative charge, can be adsorbed onto the surface of serpentine through electrostatic interaction, changing the surface charge of serpentine and thus desorbing it from the surfaces of pyrite and chalcopyrite. Nanocellulose can also cause flocculation of serpentine, preventing it from entering the concentrate through mechanical entrainment. These results demonstrate that the serpentine inhibitor nanocellulose used in this invention has a significant inhibitory effect, while also being low in cost, widely available from raw materials, and environmentally friendly with minimal impact.

Claims

1. The application of a serpentine inhibitor in the flotation of copper and nickel ore, comprising the following steps: 1) Grinding: The raw copper-nickel ore is ground and then prepared into a slurry; 2) Flotation: First, add serpentine inhibitor to the slurry from step 1) and stir, then add ethyl xanthate and stir, then add No. 2 oil and stir to carry out flotation of chalcopyrite and nickel pyrite to obtain a copper-nickel mixed concentrate; The serpentine inhibitor is nanocellulose, which has at least one of the hydrophilic groups hydroxyl, sulfonic acid, and carboxyl groups on its surface; the nanocellulose is a monodisperse particle with a diameter of 20-200 nm and a length of 50-1000 nm; in the flotation of copper-nickel ore, the nanocellulose can selectively inhibit serpentine in copper-nickel ore, thereby separating serpentine from copper-nickel ore; the nanocellulose also has a flocculation effect, enabling fine-grained serpentine to flocculate.

2. The application of the serpentine inhibitor according to claim 1 in the flotation of copper and nickel ore, characterized in that, In step 1), the copper-nickel ore is ground to a fineness of -74 μm, accounting for 60% to 85%.

3. The application of the serpentine inhibitor according to claim 1 in the flotation of copper and nickel ore, characterized in that, In step 2), flotation includes roughing, sweeping, and cleaning.

4. The application of the serpentine inhibitor according to claim 3 in the flotation of copper and nickel ore, characterized in that, In step 2), flotation includes 1-2 roughing processes, 2-3 sweeping processes, and 2-3 cleaning processes.

5. The application of the serpentine inhibitor according to claim 1 in the flotation of copper and nickel ore, characterized in that, In step 2), the stirring time for adding nanocellulose to the slurry is 2-6 minutes, the stirring time for adding ethyl xanthate to the slurry is 2-6 minutes, and the stirring time for adding No. 2 oil to the slurry is 2-6 minutes.

6. The application of the serpentine inhibitor according to claim 1 in the flotation of copper and nickel ore, characterized in that, In step 2), the amount of nanocellulose added is 100~2000 g / t relative to the copper-nickel ore.

Images