A copper-nickel ore two-stage grinding and flotation beneficiation process

Abstract

The invention discloses a copper-nickel ore two-stage grinding and flotation beneficiation process. The automatic classification function of the Isa mill is utilized to realize open-circuit grinding, qualified products can be discharged in time, over-crushing of materials is effectively reduced, useful minerals are fully monomerized and dissociated, and grinding products with narrow particle size distribution are produced. Meanwhile, microbubble flotation is adopted to strengthen the recovery of fine-grained minerals, improve the concentrate quality and metal recovery rate, enhance the economic benefits, and solve the problems of low classification efficiency, too wide particle size distribution, serious over-grinding, and difficulty in recovering fine-grade metal particles, which are common in the two-stage grinding and flotation process of the copper-nickel ore beneficiation plant.

Description

Technical Field

[0001] The invention relates to the technical field of copper-nickel ore dressing, and in particular to a copper-nickel ore two-stage grinding and flotation dressing process. Background Art

[0002] The nickel content of the second-stage pulp of copper-nickel ore is about 0.20-0.80%. Usually, the yield of the second-stage pulp entering the second-stage ball mill is more than 100%. The minerals in the second-stage pulp are mostly useful minerals with fine particle size and poor monomer dissociation. After classification by the cyclone, most of the particles are discharged by the overflow of the cyclone and have no chance to enter the ball mill for re-grinding, resulting in excessive circulation, low concentrate quality, and low metal recovery. At present, ball milling is used for grinding the second-stage pulp of copper-nickel ore, and the particle size is relatively coarse, resulting in a wide distribution of useful copper-nickel minerals in the grinding product, serious over-grinding, and an increase in the content of particles less than 38μm. Mechanical flotation machines are generally used for post-grinding flotation operations. Mechanical flotation machines have poor flotation effects when recovering fine particle minerals less than 38μm, resulting in low flotation efficiency. In addition, traditional ball mills use iron media. Iron media grinding easily forms metal precipitation and iron hydroxide film on the surface of mineral particles, thereby affecting the flotation and selectivity of minerals. Therefore, how to improve the monomer dissociation of useful minerals in the grinding process while reducing the mudification of gangue minerals such as serpentine and chlorite, inhibit over-grinding, and strengthen the flotation of fine-grained particles after ball milling is the key to strengthening the recovery of fine-grained metals in the second-stage grinding and flotation classification and improving the quality of concentrates. Summary of the invention

[0003] The invention provides a copper-nickel ore two-stage grinding and flotation beneficiation process, which aims to solve the problems of serious over-grinding phenomenon and poor monomer dissociation degree in the existing grinding process, poor recovery effect of fine-particle metal by traditional mechanical flotation machine, and low metal recovery rate.

[0004] The present invention is a copper-nickel ore two-stage grinding and flotation beneficiation process, comprising the following steps:

[0005] Step 1: The second-stage pulp obtained after the first-stage roughing of the raw ore is concentrated to a concentration of 45-55%. The concentrated pulp is sent to the Isa mill for fine grinding to obtain a narrow-grade grinding product with a particle size of -38µm accounting for 75-85%;

[0006] Step 2: Add water to the grinding product obtained in step 1 to adjust the slurry to a concentration of 18-25%, send it to the first microbubble flotation machine for second-stage roughing, add 100-120g / t of collector ethyl xanthate and 50-60g / t of butyl ammonium black powder to obtain coarse concentrated foam and coarse tailings;

[0007] Step 3: sending the coarse tailings obtained in step 2 to the third microbubble flotation machine for a scavenging selection, adding 50-60 g / t of collector ethyl xanthate and 5-10 g / t of butyl ammonium black powder, to obtain a scavenging fine foam and a scavenging tailings;

[0008] Step 4: sending the coarse concentrate foam obtained in step 2 to the second microbubble flotation machine for primary concentration to obtain primary concentrate foam and primary concentrated tailings; combining the primary concentrated tailings and the primary sweep concentrate foam obtained in step 3 and returning them to the second stage pulp concentration operation;

[0009] Step 5: Send the primary scavenging tailings obtained in step 3 to the fifth microbubble flotation machine for secondary scavenging, add 10-20g / t of collector ethyl xanthate and 0-5g / t of butyl ammonium black powder to obtain secondary scavenging foam and tailings; the secondary scavenging foam returns to the primary scavenging operation;

[0010] Step 6: The primary concentrate foam obtained in step 4 is sent to the fourth microbubble flotation machine for secondary concentration to obtain a second-stage copper-nickel concentrate product and secondary concentrated tailings; the secondary concentrated tailings are returned to the primary concentration operation.

[0011] Preferably, the second-stage slurry particle size of step one is -75µm, accounting for 55-70%, and the nickel content is 0.20-0.80%.

[0012] Preferably, the grinding medium of the Isa mill in step 1 is ceramic with a particle size of 1-6 mm.

[0013] Preferably, the first microbubble flotation machine, the second microbubble flotation machine, the third microbubble flotation machine, the fourth microbubble flotation machine, and the fifth microbubble flotation machine are all micro-nano bubble flotation machines.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The copper-nickel ore two-stage grinding and flotation beneficiation process provided by the present invention uses an Isa mill instead of a ball mill. The Isa mill has an automatic classification function and can realize open-circuit grinding. It does not need to form a closed-circuit grinding cycle with a cyclone. Qualified products can be discharged in time, effectively avoiding the over-grinding of materials. The obtained product particle size distribution is narrow, the grinding particle size distribution is optimized, and a better grinding fineness is provided for microbubble flotation. In addition, the grinding fineness of a traditional ball mill is generally -74µm, accounting for 75-85%, and the particle size is coarse. Most of the useful particles cannot be fully monomerized. The Isa mill has a finer grinding particle size, which greatly improves the monomer dissociation degree of useful nickel and copper minerals.

[0016] 2. In the copper-nickel ore two-stage grinding and flotation beneficiation process provided by the present invention, the grinding medium of the Isa mill is ceramic, which replaces the steel ball medium of the traditional ball mill, and solves the problem that iron medium grinding easily causes metal precipitation and iron hydroxide film to form on the surface of mineral particles, thereby affecting the flotation and selectivity of the mineral, making the ground product more conducive to subsequent flotation operations.

[0017] 3. The copper-nickel ore two-stage grinding and flotation beneficiation process provided by the present invention uses a micro-nano bubble flotation machine that can generate a large number of micro-nano bubbles, greatly increasing the collision probability between mineral particles and bubbles. The bubbles have a large specific surface area and high surface energy, and can act as a secondary collector for minerals. Compared with traditional flotation machines in the prior art, microbubble flotation has a stronger ability to capture fine-grained minerals, and can significantly improve the metal recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a process flow chart of the two-stage grinding and flotation of copper-nickel ore of the present invention;

[0019] Figure 2 This is a comparative diagram of the degree of dissociation of the target mineral after grinding by a conventional ball mill and the Isa mill of the present invention;

[0020] Figure 3 This is the particle size composition of the traditional ball mill grinding product and the laser particle size analysis measurement diagram;

[0021] Figure 4 This is a graph showing the particle size composition of the ISA mill grinding product and the laser particle size analysis measurement diagram of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with embodiments and drawings:

[0023] Example 1

[0024] The raw ore was taken from the second stage slurry before ball milling in a copper-nickel ore dressing plant, containing 0.47% nickel and 0.15% copper. The following steps were used to treat the second stage slurry:

[0025] Step 1: The second-stage pulp obtained after the first-stage roughing of the raw ore is concentrated to a concentration of 50%. After the concentration meets the grinding requirements of the Isa Mill, the concentrated pulp is sent to the Isa Mill for fine grinding. The grinding medium of the Isa Mill is a ceramic with a particle size of 3mm. Fine grinding obtains a narrow-grade grinding product with a particle size of -38µm accounting for 81.77%;

[0026] Step 2: add water to the grinding product obtained in step 1 to adjust the slurry to a concentration of 20%. After the concentration meets the working requirements of the nano-microbubble flotation machine, send it to the first microbubble flotation machine for second-stage roughing, add 100g / t of collector ethyl xanthate and 60g / t of butyl ammonium black powder to obtain coarse fine foam and coarse tailings;

[0027] Step 3: Send the coarse tailings obtained in step 2 to the third microbubble flotation machine for a scavenging selection, add 60g / t of ethyl xanthate and 10g / t of butyl ammonium black powder as collectors, and obtain a scavenging fine foam and a scavenging tailings;

[0028] Step 4: sending the coarse concentrate foam obtained in step 2 to the second microbubble flotation machine for primary concentration to obtain primary concentrate foam and primary concentrated tailings; combining the primary concentrated tailings and the primary sweep concentrate foam obtained in step 3 and returning them to the second stage pulp concentration operation;

[0029] Step 5: Send the primary scavenging tailings obtained in step 3 to the fifth microbubble flotation machine for secondary scavenging, add 10g / t of collector ethyl xanthate, and obtain secondary scavenging foam and tailings containing 0.15% nickel and 0.09% copper; the secondary scavenging foam is returned to the primary scavenging operation;

[0030] Step six: The primary concentrate foam obtained in step four is sent to the fourth microbubble flotation machine for secondary concentration to obtain a second-stage copper-nickel concentrate product containing 6.66% nickel and 1.47% copper and secondary concentrated tailings; the secondary concentrated tailings are returned to the primary concentration operation.

[0031] The first microbubble flotation machine, the second microbubble flotation machine, the third microbubble flotation machine, the fourth microbubble flotation machine and the fifth microbubble flotation machine are all micro-nano bubble flotation machines.

[0032] The comparative analysis of the dissociation degree of the target minerals of the grinding products of the conventional ball mill and the Isa mill of the present invention is shown in Table 1:

[0033] Table 1 Dissociation degree of pentlandite (%)

[0034]

[0035] As shown in Table 1, the dissociation degree of pentlandite monomer in ball milling is 51.36%, and the intergrowth with gangue minerals is 32.16%. The dissociation degree of pentlandite monomer in Isa milling is increased to 65.73%, and the relative content of intergrowth with gangue minerals is reduced to 25.20%. The comparison of the dissociation of pentlandite in conventional ball mill and Isa mill of the present invention is shown in the figure. Figure 2 As shown in the figure, by comparison, it can be seen that the dissociation degree of pentlandite in the Isa mill product is greatly improved. The particle size composition of the traditional ball mill product and the laser particle size analysis are shown in the figure. Figure 3 As shown in the figure, the particle size composition of the ISAMA mill grinding product and the laser particle size analysis are as follows Figure 4 As shown, combined Figure 3-4 It can be seen that the grinding product with narrow particle size distribution can be obtained by Isa mill.

[0036] The comparison of mineral processing indicators between the conventional flotation machine and the micro-nano bubble flotation machine of the present invention is shown in Table 2:

[0037] Table 2 Comparison results of copper-nickel ore dressing indicators (%)

[0038]

[0039] As shown in Table 2, compared with the traditional flotation machine, the micro-nano bubble flotation machine of the present invention has an increase of 1.78% in nickel grade and 0.43% in copper grade of the second-stage copper-nickel mixed concentrate, an increase of 5.89% in nickel recovery rate and an increase of 4.75% in copper recovery rate.

[0040] Example 2

[0041] The raw ore was taken from the second stage slurry before entering the ball mill of a low-grade copper-nickel concentrator, containing 0.27% nickel and 0.11% copper. The following steps were used to conduct a semi-industrial expansion test of the second stage slurry with a daily processing capacity of 50 tons:

[0042] Step 1: The second-stage pulp obtained after the first-stage roughing of the raw ore is concentrated to a concentration of 50%. After the concentration meets the grinding requirements of the Isa Mill, the concentrated pulp is sent to the Isa Mill for fine grinding. The grinding medium of the Isa Mill is a ceramic with a particle size of 3mm. Fine grinding obtains a narrow-grade grinding product with a particle size of -38µm accounting for 80%;

[0043] Step 2: add water to the grinding product obtained in step 1 to adjust the slurry to a concentration of 20%. After the concentration meets the working requirements of the nano-microbubble flotation machine, send it to the first microbubble flotation machine for second-stage roughing, add 110g / t of collector ethyl xanthate and 55g / t of butyl ammonium black powder to obtain coarse fine foam and coarse tailings;

[0044] Step 3: Send the coarse tailings obtained in step 2 to the third microbubble flotation machine for a scavenging selection, add 50 g / t of ethyl xanthate and 5 g / t of butyl ammonium black powder as collectors, and obtain a scavenging fine foam and a scavenging tailings;

[0045] Step 4: sending the coarse concentrate foam obtained in step 2 to the second microbubble flotation machine for primary concentration to obtain primary concentrate foam and primary concentrated tailings; combining the primary concentrated tailings and the primary sweep concentrate foam obtained in step 3 and returning them to the second stage pulp concentration operation;

[0046] Step 5: Send the primary scavenging tailings obtained in step 3 to the fifth microbubble flotation machine for secondary scavenging, add 15g / t of ethyl xanthate and 3g / t of butyl ammonium black powder as collectors, and obtain secondary scavenging foam and tailings containing 0.12% nickel and 0.07% copper; the secondary scavenging foam is returned to the primary scavenging operation;

[0047] Step 6: The primary concentrate foam obtained in step 4 is sent to the fourth microbubble flotation machine for secondary concentration to obtain a second-stage copper-nickel concentrate product containing 4.81% nickel and 1.22% copper and secondary concentrated tailings; the secondary concentrated tailings are returned to the primary concentration operation.

[0048] The first microbubble flotation machine, the second microbubble flotation machine, the third microbubble flotation machine, the fourth microbubble flotation machine and the fifth microbubble flotation machine are all micro-nano bubble flotation machines.

[0049] The comparison of mineral processing indicators between the conventional flotation machine and the micro-nano bubble flotation machine of the present invention is shown in Table 3:

[0050] Table 3 Comparison results of copper-nickel ore dressing indicators (%)

[0051]

[0052] As shown in Table 3, compared with the traditional flotation machine, the micro-nano bubble flotation machine of the present invention has an increase of 1.90% in nickel grade and 0.52% in copper grade of the second-stage copper-nickel mixed concentrate, an increase of 6.65% in nickel recovery rate and an increase of 7.40% in copper recovery rate.

[0053] Example 3

[0054] After the first stage of separation, the second stage of the ore pulp before the ball mill contains 0.60% nickel and 0.13% copper. The following process steps are used to conduct an industrial test of the second stage ore pulp with a scale of 1,500 tons / day:

[0055] Step 1: The second-stage pulp obtained after the first-stage roughing of the raw ore is concentrated to a concentration of 48%. After the concentration meets the grinding requirements of the Isa Mill, the concentrated pulp is sent to the Isa Mill for fine grinding. The grinding medium of the Isa Mill is a ceramic with a particle size of 6mm. Fine grinding obtains a narrow-grade grinding product with a particle size of -38µm accounting for 85%;

[0056] Step 2: add water to the grinding product obtained in step 1 to adjust the slurry to a concentration of 22%. After the concentration meets the working requirements of the nano-microbubble flotation machine, it is sent to the first microbubble flotation machine for second-stage roughing, and 120g / t of collector ethyl xanthate and 50g / t of butyl ammonium black powder are added to obtain coarse fine foam and coarse tailings;

[0057] Step 3: sending the coarse tailings obtained in step 2 to the third microbubble flotation machine for a scavenging selection, adding 55 g / t of ethyl xanthate and 9 g / t of butyl ammonium black powder as collectors, to obtain a scavenging fine foam and a scavenging tailings;

[0058] Step 4: sending the coarse concentrate foam obtained in step 2 to the second microbubble flotation machine for primary concentration to obtain primary concentrate foam and primary concentrated tailings; combining the primary concentrated tailings and the primary sweep concentrate foam obtained in step 3 and returning them to the second stage pulp concentration operation;

[0059] Step 5: Send the primary scavenging tailings obtained in step 3 to the fifth microbubble flotation machine for secondary scavenging, add 20g / t of ethyl xanthate and 5g / t of butyl ammonium black powder as collectors, and obtain secondary scavenging foam and tailings containing 0.13% nickel and 0.07% copper; the secondary scavenging foam is returned to the primary scavenging operation;

[0060] Step six: The primary concentrate foam obtained in step four is sent to the fourth microbubble flotation machine for secondary concentration to obtain a second-stage copper-nickel concentrate product containing 6.39% nickel and 0.96% copper and secondary concentrated tailings; the secondary concentrated tailings are returned to the primary concentration operation.

[0061] The first microbubble flotation machine, the second microbubble flotation machine, the third microbubble flotation machine, the fourth microbubble flotation machine and the fifth microbubble flotation machine are all micro-nano bubble flotation machines.

[0062] The comparison of mineral processing indicators between the conventional flotation machine and the micro-nano bubble flotation machine of the present invention is shown in Table 4:

[0063] Table 4 Comparison results of copper-nickel ore dressing indicators (%)

[0064]

[0065] As shown in Table 4, compared with the traditional flotation machine, the micro-nano bubble flotation machine of the present invention has an increase of 0.94% in nickel grade and 0.24% in copper grade of the second-stage copper-nickel mixed concentrate, an increase of 4.22% in nickel recovery rate and an increase of 8.42% in copper recovery rate.

Claims

1. A copper-nickel ore two-stage grinding and flotation beneficiation process, characterized in that: The following steps are involved: Step 1: The second-stage pulp obtained after the first-stage roughing of the raw ore is concentrated to a concentration of 45-55%, and the concentrated pulp is sent to the Isa mill for fine grinding to obtain a narrow-grade grinding product with a particle size of -38µm accounting for 75-85%; the grinding medium of the Isa mill is ceramic with a particle size of 1-6mm; Step 2: Add water to the grinding product obtained in step 1 to adjust the slurry to a concentration of 18-25%, send it to the first microbubble flotation machine for second-stage roughing, add 100-120g / t of collector ethyl xanthate and 50-60g / t of butyl ammonium black powder to obtain coarse concentrated foam and coarse tailings; Step 3: sending the coarse tailings obtained in step 2 to the third microbubble flotation machine for a scavenging selection, adding 50-60 g / t of collector ethyl xanthate and 5-10 g / t of butyl ammonium black powder, to obtain a scavenging fine foam and a scavenging tailings; Step 4: sending the coarse concentrate foam obtained in step 2 to the second microbubble flotation machine for primary concentration to obtain primary concentrate foam and primary concentrated tailings; combining the primary concentrated tailings and the primary sweep concentrate foam obtained in step 3 and returning them to the second stage pulp concentration operation; Step 5: Send the primary scavenging tailings obtained in step 3 to the fifth microbubble flotation machine for secondary scavenging, add 10-20g / t of collector ethyl xanthate and 0-5g / t of butyl ammonium black powder to obtain secondary scavenging foam and tailings; the secondary scavenging foam returns to the primary scavenging operation; Step 6: The primary concentrate foam obtained in step 4 is sent to the fourth microbubble flotation machine for secondary concentration to obtain a second-stage copper-nickel concentrate product and secondary concentrated tailings; the secondary concentrated tailings are returned to the primary concentration operation.

2. A copper-nickel ore two-stage grinding and flotation beneficiation process as claimed in claim 1, characterized in that: The particle size of the second-stage ore slurry in step 1 is -75µm, accounting for 55-70%, and the nickel content is 0.20-0.80%.

3. A copper-nickel ore two-stage grinding and flotation beneficiation process as claimed in claim 1 or 2, characterized in that: The first microbubble flotation machine, the second microbubble flotation machine, the third microbubble flotation machine, the fourth microbubble flotation machine and the fifth microbubble flotation machine are all micro-nano bubble flotation machines.

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