Beneficiation method for optimizing two-stage ore grinding and flotation process of copper-nickel sulfide ore flotation middling

Abstract

The invention discloses a beneficiation method for optimizing a copper-nickel sulfide ore flotation middling two-stage ore grinding and flotation process, and aims to solve the problem of high content of over-abrasive particles in two-stage ore grinding products and two-stage flotation feeding particle size composition in a copper-nickel sulfide ore stage ore grinding separation process. The method comprises the following steps: designing and optimizing a second-stage grinding and floating process, namely carrying out first-stage grinding, first-stage roughing and concentration on raw ore to generate first-stage roughing tailings (middling 1) and first-stage concentration tailings (middling 2); middlings 1 are pre-graded through a cyclone, overflow directly enters second-stage flotation, and settled sand is selectively fed into the second-stage flotation in an open-circuit mode or returned to be graded in a closed-circuit mode after being ground through a ball mill; and second-section fine tailings (middlings 3), scavenging concentrate (middlings 4) and first-section fine tailings (middlings 2) of second-section flotation are directly returned to second-section roughing without grinding. According to the method, metal loss caused by over-grinding of fine-fraction minerals can be reduced, the ore grinding load and energy consumption are reduced, and the operation efficiency and the concentrate recovery rate are improved.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and in particular to a mineral processing method for optimizing the two-stage grinding and flotation process of copper-nickel sulfide ore flotation, which aims to reduce ore over-grinding, optimize product particle size distribution, reduce energy consumption in the mineral processing process, and enhance the recovery of fine-grained minerals. Background Technology

[0002] With the deepening of mining operations, the mineral distribution relationships in copper-nickel sulfide ores become increasingly complex, rendering traditional grinding and flotation processes inadequate for efficient processing. In conventional stage flotation and middlings regrinding processes, significant over-grinding of copper-nickel sulfide minerals occurs during the second-stage grinding, leading to increased energy consumption and low grinding efficiency. Furthermore, the flotation pulp after middlings regrinding contains a high proportion of fine-grained minerals, which existing flotation processes fail to effectively separate, impacting the overall stable improvement of nickel-copper grades and recovery rates. Therefore, a new technological solution is needed to address these issues. Summary of the Invention

[0003] To address the problems of metal loss and low operating efficiency caused by excessive grinding particle size in existing technologies, a method for beneficiating copper-nickel sulfide ore is provided that optimizes the middlings circulation path and grinding process to reduce over-grinding, decrease metal loss, and improve grinding efficiency and system processing capacity.

[0004] This invention optimizes the beneficiation method for the middlings grinding and flotation process in the flotation of copper-nickel sulfide ore. After the raw ore undergoes a first-stage grinding, a first-stage roughing, and a first-stage cleaning process, a first-stage roughing tailings (middlings 1) and a first-stage cleaning tailings (middlings 2) are produced. The middlings regrinding process and the flotation process are optimized through the following process: (1) Two-stage grinding with pre-classification: The middlings 1 after the first-stage grinding is processed through a two-stage grinding process with pre-classification so that it enters the second-stage flotation process, avoiding the fine-grained minerals from re-entering the ball mill and reducing over-grinding.

[0005] Hydrocyclones are used to pre-classify the middlings 1. The overflow after classification directly enters the second-stage flotation process, and the underflow enters the ball mill for grinding. The ball mill discharge is selectively fed into the second-stage flotation or returned to the classification operation via a closed circuit. A controllable flow path is constructed using valves and tees, allowing the ball mill discharge to be selectively fed into the secondary flotation stage or returned to the hydrocyclone for classification, depending on operational needs. By shutting down some ball mills and hydrocyclones, the throughput of the secondary grinding stage is reduced, thus minimizing the generation of over-grinding particles.

[0006] (2) Improved middlings recycling: After the second stage of roughing, second stage cleaning and scavenging, the tailings (middlings 3) and scavenging concentrate (middlings 4) produced by the second stage of flotation and the tailings (middlings 2) of the first stage of cleaning are directly fed into the second stage of roughing without grinding, so as to avoid these middlings from entering the ball mill again and reduce the phenomenon of over-grinding.

[0007] The particle size composition of middlings 1, 2, 3, and 4 was analyzed by particle size distribution testing. Based on the analysis results, the middlings circulation volume was dynamically adjusted to prevent fine-grained minerals from entering the ball mill for regrinding. To address the issue of a high proportion of fine-grained minerals in the flotation pulp, the flotation process structure was adjusted; by adding flotation columns and stirring tanks, the effective separation of fine-grained minerals was ensured, thereby improving nickel-copper grade and recovery rate.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: Reduced over-grinding: Improved open-circuit grinding and middlings recycling significantly reduced re-grinding of fine-grained minerals, thus reducing over-grinding and metal loss. Optimized product particle size distribution: Increased recovery of fine-grained minerals and improved product particle size distribution. Increased nickel-copper grade and recovery: The optimized flotation process is more conducive to the separation of fine-grained minerals, improving nickel-copper grade and recovery. Energy saving and consumption reduction: Reduced unnecessary grinding and classification operations lowered energy consumption and improved production efficiency. Attached Figure Description

[0009] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0011] Example 1: A copper-nickel sulfide ore beneficiation plant with a daily ore processing capacity of 6,000 tons uses a conventional two-stage grinding and staged flotation process, followed by middlings regrinding. It was found that the content of over-grinded particles in the particle size distribution of the two-stage grinding product and the two-stage flotation feed was too high, resulting in high energy consumption and the inability to effectively recover some metals.

[0012] A mineral processing method employing optimized two-stage grinding and flotation processes in the flotation of copper-nickel sulfide ores includes the following steps: (1) After the raw ore undergoes a grinding process and a roughing and cleaning process, a roughing tailings (medium ore 1) and a cleaning tailings (medium ore 2) are produced. The roughing tailings (medium ore 1) are subjected to a two-stage grinding process with pre-classification so that they can enter the two-stage flotation process. After implementation, the probability of fine-grained minerals entering the ball mill was reduced, thus mitigating over-grinding. By shutting down some ball mills and hydrocyclones, the processing volume of the second-stage grinding was reduced, preventing these middlings from re-entering the ball mill and further reducing over-grinding. Before the middlings 1 from the first-stage grinding enter the second-stage grinding, a pre-classification device (hydrocyclone) was added to pre-classify the middlings 1. After classification, the fine-grained portion directly enters the second-stage flotation process, while the coarse-grained portion enters the ball mill for regrinding. Valves and tees are installed in the ball mill discharge path to form a controllable live process: switching between open-circuit mode (discharge directly enters the second-stage flotation) or closed-circuit mode (discharge returns to the classification operation) according to the operating conditions.

[0013] (2) After two stages of roughing, two stages of cleaning and scavenging, the cleaned tailings (medium ore 3) and scavenged concentrate (medium ore 4) and the first stage cleaned tailings (medium ore 2) are fed directly into the second stage roughing without grinding.

[0014] To address the issue of a high proportion of fine-grained minerals in the flotation pulp, flotation columns and stirred tanks were added to ensure effective separation of these minerals. The use of flotation columns improved the recovery rate of fine-grained minerals, thereby increasing the grade and recovery rate of nickel and copper.

[0015] Evaluation of the effectiveness of this mineral processing method: Reduced over-grinding: Compared with existing processes, it effectively reduces the amount of fine-grained minerals entering the ball mill, thus reducing over-grinding. The content of over-grinded particles in the second-stage flotation feed is significantly reduced, and the content of -10 micron particles in the slurry is reduced by 13.5%.

[0016] Optimize product particle size distribution: The particle size distribution of flotation products is more uniform, the recovery rate of fine-grained minerals is significantly improved, and the particle size distribution of the products is improved.

[0017] Improved nickel and copper grades and recovery rates: The optimization of the flotation process structure has enabled better separation of fine-grained minerals, resulting in a significant improvement in nickel and copper grades and recovery rates (compared to the existing process, the copper grade of the two-stage concentrate product has increased by 0.3 percentage points, the copper recovery rate by 1.1 percentage points, and the nickel recovery rate by 0.4 percentage points), achieving the expected goals.

[0018] Energy saving and consumption reduction: unnecessary grinding operations were reduced, electricity consumption was lowered, production efficiency was improved, and the overall energy consumption of the two-stage grinding and flotation operation was reduced by about 15%.

Claims

1. A mineral processing method for optimizing the two-stage grinding and flotation process of copper-nickel sulfide ore flotation, wherein the raw ore undergoes a first-stage grinding and a first-stage roughing and a first-stage cleaning process, producing a first-stage roughing tailings and a first-stage cleaning tailings, characterized in that, Includes the following steps: (1) The tailings from the first roughing stage are subjected to a two-stage grinding process with pre-classification so that they can enter the second-stage flotation process; The tailings from the first stage roughing process are pre-classified using hydrocyclones. The overflow after classification directly enters the second stage flotation process, and the underflow enters the ball mill for grinding. The ball mill discharge is selectively fed into the second stage flotation process via open circuit or returned to the classification operation via closed circuit. (2) After two stages of roughing, two stages of cleaning and scavenging, the tailings from the second stage cleaning and the concentrate from the first stage cleaning are fed directly into the second stage roughing without grinding.

2. The method according to claim 1, characterized in that, In step (1), a controllable flow is constructed through valves and tees, so that the ball mill discharge can be selectively fed into the second-stage flotation or returned to the hydrocyclone for classification according to the operation requirements.

3. The method according to claim 1 or 2, characterized in that, The particle size distribution of tailings from the first stage roughing process, the first stage cleaning process, the second stage cleaning process, and the scavenging concentrate is analyzed by particle size detection. Based on the analysis results, the distribution of middlings circulation is dynamically adjusted to prevent fine-grained minerals from entering the ball mill for regrinding.

4. The method according to claim 1, characterized in that, In step (1), by shutting down some ball mills and hydrocyclones, the amount of material processed in the second-stage grinding is reduced, thereby reducing the generation of over-grind particles.

5. The method according to claim 1, characterized in that, It also includes adjustments to the structure of the two-stage flotation process: by adding flotation columns and stirring tanks, the adhesion and separation of fine-grained mineral bubbles are enhanced, thereby improving the grade and recovery rate of nickel-copper concentrate.

Images