Method for determining grinding fineness of two-stage ball milling in efficient copper smelting slag sorting process

Abstract

The invention discloses a method for determining the grinding fineness of two-stage ball milling in an efficient copper smelting slag sorting process. The method comprises the following steps that S1, the particle size composition of flotation tailings after the grinding fineness of the two-stage ball milling is accurately increased is measured; s2, the actual optimal copper content index of the total tailings under the fineness D1 is determined; s3, determining the copper content of different tailings after the grinding fineness of the second-stage ball milling is accurately reduced; and S4, the optimal two-stage ball-milling ore grinding fineness range is determined. According to different actual conditions, the optimal total tailing copper content index can be theoretically and actually obtained when the copper smelting slag with the property is subjected to an efficient grading process, and the method has important guiding significance on production.

Description

Technical Field

[0001] The invention relates to the field of slag beneficiation, and in particular to a method for reasonably determining a two-stage ball milling fineness range in a copper smelting slag efficient beneficiation process. Background Art

[0002] The criterion for judging the effect of copper smelting slag separation is the copper content of slag flotation tailings. Generally speaking, the most direct factor affecting the copper content of slag flotation tailings is the grinding fineness. The lower the grinding fineness, the lower the copper content of slag tailings. However, after long-term research, it is found that the validity of this law is closely related to different grinding processes and grinding fineness parameters.

[0003] At present, in actual production, copper smelting slag usually adopts the "semi-autogenous grinding + ball mill direct grinding" process or the "two-stage ball milling stage grinding stage selection" process in the front-end grinding. The second-stage grinding equipment of these two processes is a ball mill. In actual production, the second-stage ball milling fineness is usually -0.045mm, accounting for 70% to 85% of the range, depending on the on-site equipment and grinding capacity. At this time, the copper content of the slag flotation tailings can be effectively reduced by improving the ball milling capacity.

[0004] The efficient separation process of "classification + coarse particle regrinding and reselection" for slag flotation tailings can further reduce the copper content in slag flotation tailings on the basis of the above two grinding processes and the unchanged fineness of the on-site second-stage ball milling. However, if the fineness of the second-stage ball milling of flotation is still increased blindly at this time, it will often have a counterproductive effect on the copper content of the final slag flotation tailings. At present, there is no relevant theoretical basis for how to reasonably determine the second-stage ball milling fineness of copper smelting slag while meeting both technical and economic requirements in the efficient separation process, and it is impossible to scientifically guide actual production. Summary of the invention

[0005] A technical problem solved by the present invention is the problem of reasonably determining the grinding fineness of the second-stage ball mill in the efficient separation process of copper smelting slag; a method is provided to utilize the difference in copper content in tailings of different properties and the difference in fine grinding efficiency of different mills to accurately control the grinding fineness in different stages of grinding operations of copper smelting slag, thereby obtaining the optimal copper content index of flotation tailings while avoiding the increase of grinding energy consumption.

[0006] The technical scheme adopted by the present invention is: a method for determining the fineness of the second-stage ball mill in the efficient separation process of copper smelting slag, comprising the following steps: S1, determining the particle size composition of the flotation tailings after the fineness of the second-stage ball mill is accurately increased, continuously improving the fineness of the second-stage ball mill, determining the particle size of the scavenging tailings obtained by the second-stage ball mill with different finenesses, and determining the second-stage ball mill fineness D1 when the copper content of the finest particle size in the scavenging tailings is in a stable range; S2, determining the actual optimal copper content index of the total tailings under the fineness D1, classifying the scavenging tailings under the fineness D1, the fine particles are the under-screen tailings, and the coarse particle tailings are regrinded and re-selected, thereby obtaining the re-selected tailings; at this time, the copper grade calculation formula of the total tailings is as follows:

[0007]

[0008] Among them, β 总 is the copper grade of the total tailings;

[0009] γ 再选 It is the re-selected tailings yield obtained after the coarse tailings on the screen are regrinded and re-selected after the scavenged tailings are classified;

[0010] β 再选 It is the copper grade of the re-selected tailings obtained after the coarse tailings on the sieve are sized and re-grinded for re-selection.

[0011] γ 筛下 It is the yield of fine tailings after scavenging tailings classification;

[0012] β 筛下 The copper grade of fine tailings after scavenging tailings classification;

[0013] S3, determination of copper content in different tailings after the fineness of the second-stage ball milling is precisely reduced: the fineness of the second-stage ball milling is reduced from D1, that is, the particle size is coarsened, and the difference in copper content between the re-selected tailings and the under-screen tailings is used to improve the yield of coarse particles after scavenging tailings classification, measure the change in copper content in the total tailings, and compare the difference in copper content between the re-selected tailings and the under-screen tailings at D1; S4, determine the optimal range of the second-stage ball milling fineness. As the fineness of the second-stage ball milling is reduced from D1, when the difference in copper content between the re-selected tailings and the under-screen tailings at D1 is higher than 0.06 percentage points, the copper content in the re-selected tailings and the total tailings will first reach a value lower than the actual minimum value. The theoretical minimum value, at this time the second-stage ball milling fineness is D2, and then the second-stage ball milling fineness continues to decrease, and the copper content of the total tailings increases to the actual minimum value. At this time, the second-stage ball milling fineness is D3, and the range of D2 to D3 is the optimal second-stage ball milling fineness range; when the difference between the copper content of the re-selected tailings and the copper content of the under-screen tailings at D1 is between 0.04 and 0.06 percentage points, the theoretical minimum value of the total copper tailings is not obvious, and D3 is taken as the optimal second-stage ball milling fineness; when the difference between the copper content of the re-selected tailings and the copper content of the under-screen tailings at D1 is less than 0.04 percentage points, D1 is taken as the optimal second-stage ball milling fineness.

[0014] As a further improvement of the present invention, in step S1, the finest particle size of the scavenged tailings is 0.045 mm or 0.038 mm.

[0015] As a further improvement of the present invention, in step S2, the re-grinding fineness of the oversize tailings is -0.038 mm, accounting for 96% to 99%.

[0016] The present invention has the beneficial effects:

[0017] 1) The present invention determines the change curve of the influence of the second-stage ball milling fineness on the copper content of the total tailings through the copper particle loss law of the scavenging tailings in different front-end grinding processes of the copper smelting slag, the influence of the second-stage ball milling fineness on the yield of coarse particles after scavenging tailings classification, and the difference in copper content between the re-selected tailings and the under-screen tailings. The curve can be used to obtain the optimal second-stage ball milling fineness range of the copper smelting slag of this nature that meets both technical and economic requirements;

[0018] 2) The present invention organically combines mathematical principles with industrial applications, and can more conveniently predict the fineness and suitable range of the second-stage ball milling, and can quickly respond to on-site production adjustments;

[0019] 3) The present invention can obtain the optimal total tailings copper content index when the copper smelting slag of this nature adopts an efficient separation process in theory and in practice according to different actual conditions, which has important guiding significance for production;

[0020] 4) The present invention searches for and determines the optimal second-stage ball milling fineness through two stages, fully utilizes the difference in fine grinding efficiency between ball mill and vertical mill, significantly reduces the comprehensive energy consumption of grinding, and has important guiding significance for on-site production cost reduction and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a process flow chart for the efficient separation of copper smelting slag according to the present invention.

[0022] Figure 2 It is a schematic diagram of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] In small-scale tests and industrial production, the copper particle loss law of scavenging tailings in different front-end grinding processes of copper smelting slag was found, that is, with the increase of the second-stage ball milling fineness, the copper loss of scavenging tailings gradually decreased, the fine particle yield also increased accordingly, and the total tailings copper content and fine particle copper content index gradually approached. Among them, when the grinding fineness is coarse, the copper grade of copper tailings is affected by both the yield and copper grade of different particle sizes; when the grinding fineness is fine, the copper grade of different particle sizes in the tailings is basically in a stable state, and the copper content of copper tailings is only related to the yield change between different particle sizes. The second-stage ball milling fineness when this influencing factor is converted from two to one is the lowest second-stage ball milling fineness D1 when the copper content of the finest particle size in the scavenging tailings is in a stable range.

[0025] Focusing on the changing rules of copper smelting slag, it is found that for coarse-grained tailings and fine-grained tailings after scavenging tailings classification, the copper particles in the coarse-grained tailings are relatively large, the proportion of copper inclusions is relatively small, and the copper particles are relatively easier to dissociate. Therefore, under the condition of similar relative grinding fineness, the copper content of coarse-grained tailings after re-selection can be significantly lower than that of fine-grained tailings, and its absolute value can be in a stable range, which is a stable factor; while the copper content index of fine particles will be related to the on-site grinding effect and the properties of copper smelting slag, which is an unstable factor. Based on this, there is a traceable rule between the copper grade of the total tailings of copper smelting slag and the fineness of the second-stage ball milling: that is, when the fineness of the second-stage grinding is coarser, the yield of coarse particles after tailings classification is larger, and the effect of regrinding and reselection is better, which affects the copper content of the total tailings to a greater extent, but the copper content of fine particles after tailings classification is relatively high; when the grinding fineness is finer, the yield of coarse particles after tailings classification is smaller, and the effect of regrinding and reselection is better, which affects the copper content of the total tailings to a smaller extent, but the copper content of fine particles after tailings classification is reduced to a stable level. In the end, the total tailings copper loss will inevitably show a trend of "high copper content on both sides and fluctuation in the middle area" affected by the fineness of the second-stage ball milling. Therefore, the critical point D3 on the left side of the middle area and the lowest point D2 are found, and the middle of the two points is the optimal second-stage ball milling fineness range that can meet both technical and economic requirements.

[0026] Example 1: Double flash copper slag from Anhui XX Copper Company, the original slag copper grade is 1.69%, the copper phase is mainly matte phase, followed by metallic copper phase.

[0027] a) Determination of particle size composition of flotation tailings after precise increase of the second-stage ball milling fineness: The second-stage ball milling fineness was continuously increased, and the particle size composition of the scavenging tailings obtained with different second-stage ball milling finenesses was determined to find the second-stage ball milling fineness when the finest particle size of the scavenging tailings contained copper in a stable range. As shown in Table 1, when the second-stage ball milling fineness was -0.045 mm, accounting for 87.9%, the copper content of the tailings with a particle size of -0.038 mm was in a stable range.

[0028] At this time, -0.045mm accounts for 87.9%, which is the minimum second-stage ball milling fineness when the copper content of the finest particle size in the scavenging tailings is in a stable range. It is also the highest fineness standard of the second-stage ball milling in this method.

[0029] Table 1 Results of particle size composition of scavenging tailings

[0030]

[0031] b) Obtaining the actual optimal copper content index of the total tailings of the process: The scavenging tailings with a second-stage ball milling fineness of -0.045mm accounting for 87.9% are classified using a particle size of 0.038mm, the fine particles are the under-screen tailings, the coarse particle tailings are re-grinded and re-selected, and the re-selected tailings are obtained, and a formula is created, and the results are shown in Table 2. At this time, the total tailings copper content index of 0.169% is the actual optimal copper content index of the total tailings of the process, and the second-stage ball milling fineness further becomes the highest second-stage ball milling fineness when the total tailings of the process have the actual optimal copper content index.

[0032]

[0033] β 总 : Total tailings copper grade;

[0034] γ 再选 : The yield of re-selected tailings obtained after the coarse tailings on the sieve are sized and re-grinded and re-selected after the scavenged tailings are classified;

[0035] β 再选 : The copper grade of the re-selected tailings obtained after the coarse tailings on the sieve after classification are regrinded and re-selected;

[0036] γ 筛下 : The yield of fine tailings after scavenging tailings classification;

[0037] β 筛下 : The copper grade of fine-particle tailings after scavenging tailings classification.

[0038] Table 2 Actual optimal copper content index of different tailings

[0039]

[0040] Note: The operating yield corresponds to the scavenging tailings.

[0041] c) Determination of copper content in different tailings after the fineness of the second-stage ball mill is precisely reduced: The fineness of the second-stage ball mill is reduced, and the difference in copper content between the re-selected tailings and the under-screen tailings is used to improve the yield of coarse particles after scavenging tailings classification, and the change in copper content in the total tailings is measured. The results are shown in Table 3. When the grinding fineness is -0.045mm, accounting for 87.9%, the difference in copper content between the re-selected tailings and the under-screen tailings is 0.075 percentage points, which is higher than 0.06 percentage points.

[0042] Table 3 Results of changes in copper content in total tailings

[0043]

[0044] Note: The operating yield corresponds to the scavenging tailings.

[0045] d) Determine the optimal second-stage ball milling fineness range: As the second-stage ball milling fineness gradually decreases from the highest second-stage ball milling fineness of -0.045 mm accounting for 87.9% when the actual optimal copper content of the total tailings is, the copper content of the total tailings will first reach a theoretical minimum value of 0.163% which is lower than the actual minimum value. At this time, the second-stage ball milling fineness is -0.045 mm accounting for 73.0% (D3), and then the second-stage ball milling fineness continues to decrease, and the copper content of the total tailings increases to the actual minimum value. At this time, the second-stage ball milling fineness is -0.045 mm accounting for 65.4% (D2). At this time, -0.045 mm occupies the interval of 65.4% to 73.0%, that is, D2 to D3 is the optimal second-stage ball milling fineness range for the double flash copper slag.

[0046] Example 2: Copper smelting slag of Anhui XX Copper Company, wherein smelting slag accounts for the majority, followed by converter slag, the original slag copper grade is 2.45%, and the copper phase is mainly matte phase, followed by metallic copper phase.

[0047] a) Determination of particle size composition of flotation tailings after the fineness of the second-stage ball milling is precisely increased: the fineness of the second-stage ball milling is continuously increased, and the particle size composition of the scavenging tailings obtained with different second-stage ball milling finenesses is determined to find the second-stage ball milling fineness when the finest particle size of the scavenging tailings contains copper in a stable range. As shown in Table 4, when the second-stage ball milling fineness is -0.045mm, accounting for 75.7%, the copper content of the -0.038mm particle size tailings is in a stable range. At this time, -0.045mm, accounting for 75.7%, is the lowest second-stage ball milling fineness when the finest particle size of the scavenging tailings contains copper in a stable range, and it is also the highest fineness standard of the second-stage ball milling in the inventive method;

[0048] Table 4 Results of particle size composition of scavenging tailings

[0049]

[0050] b) Obtaining the actual optimal copper content index of the total tailings of the process: The scavenging tailings with a second-stage ball milling fineness of -0.045mm accounting for 75.7% are classified using a 0.038mm particle size, the fine particles are the under-screen tailings, the coarse particle tailings are re-grinded and re-selected, and the re-selected tailings are obtained, and a formula is created, and the results are shown in Table 5. At this time, the total tailings copper content index of 0.123% is the actual optimal copper content index of the total tailings of the process, and the second-stage ball milling fineness further becomes the highest second-stage ball milling fineness when the total tailings of the process have the actual optimal copper content index.

[0051]

[0052] β 总 : Total tailings copper grade;

[0053] γ 再选 : The yield of re-selected tailings obtained after the coarse tailings on the sieve are sized and re-grinded and re-selected after the scavenged tailings are classified;

[0054] β 再选 : The copper grade of the re-selected tailings obtained after the coarse tailings on the sieve after classification are regrinded and re-selected;

[0055] γ 筛下 : The yield of fine tailings after scavenging tailings classification;

[0056] β 筛下 : The copper grade of fine-particle tailings after scavenging tailings classification.

[0057] Table 5 Actual optimal copper content index of different tailings

[0058]

[0059] Note: The operating yield corresponds to the scavenging tailings.

[0060] c) Determination of copper content in total tailings after accurate reduction of the fineness of the second-stage ball mill: The fineness of the second-stage ball mill was reduced, and the difference in copper content between the re-selected tailings and the under-screen tailings was used to increase the yield of coarse particles after scavenging tailings classification, and the change in copper content in the total tailings was determined. The results are shown in Table 6. The difference in copper content between the re-selected tailings and the under-screen tailings when the grinding fineness was 75.7% was 0.028 percentage points, which was lower than 0.04 percentage points.

[0061] Table 6 Changes in copper content in total tailings

[0062]

[0063]

[0064] Note: The operating yield corresponds to the scavenging tailings.

[0065] d) Determine the optimal second-stage ball milling fineness range: as the second-stage ball milling fineness gradually decreases from the highest second-stage ball milling fineness of -0.045 mm accounting for 75.7% when the actual optimal copper content of the total tailings is reached, the copper content of the total tailings gradually increases. At this time, -0.045 mm accounts for 75.7%, that is, D1 is the optimal second-stage ball milling fineness for the double flash copper slag.

[0066] Example 3: Copper smelting slag of Inner Mongolia XX Copper Company, wherein smelting slag accounts for the majority, followed by converter slag, the original slag copper grade is 1.86%, and the copper phase is mainly matte phase, followed by metallic copper phase.

[0067] a) Determination of particle size composition of flotation tailings after the fineness of the second-stage ball milling is precisely increased: the fineness of the second-stage ball milling is continuously increased, and the particle size composition of the scavenging tailings obtained with different second-stage ball milling finenesses is determined to find the second-stage ball milling fineness when the finest particle size of the scavenging tailings contains copper in a stable range. As shown in Table 7, when the second-stage ball milling fineness is -0.045mm, accounting for 77.8%, the copper content of the -0.038mm particle size tailings is in a stable range. At this time, -0.045mm, accounting for 77.8%, is the lowest second-stage ball milling fineness when the finest particle size of the scavenging tailings contains copper in a stable range, and it is also the highest fineness standard of the second-stage ball milling in the inventive method;

[0068] Table 7 Results of particle size composition of scavenging tailings

[0069]

[0070] b) Obtaining the actual optimal copper content index of the total tailings of the process: The scavenging tailings with a second-stage ball milling fineness of -0.045mm accounting for 77.8% are classified using a 0.038mm particle size, the fine particles are the under-screen tailings, the coarse particle tailings are re-grinded and re-selected, and the re-selected tailings are obtained, and a formula is created, and the results are shown in Table 8. At this time, the total tailings copper content index of 0.139% is the actual optimal copper content index of the total tailings of the process, and the second-stage ball milling fineness further becomes the highest second-stage ball milling fineness when the total tailings of the process have the actual optimal copper content index.

[0071]

[0072] β 总 : Total tailings copper grade;

[0073] γ 再选 : The yield of re-selected tailings obtained after the coarse tailings on the sieve are sized and re-grinded and re-selected after the scavenged tailings are classified;

[0074] β 再选 : The copper grade of the re-selected tailings obtained after the coarse tailings on the sieve after classification are regrinded and re-selected;

[0075] γ 筛下 : The yield of fine tailings after scavenging tailings classification;

[0076] β 筛下 : The copper grade of fine-particle tailings after scavenging tailings classification.

[0077] Table 8 Actual optimal copper content index of different tailings

[0078]

[0079] Note: The operating yield corresponds to the scavenging tailings.

[0080] c) Determination of copper content in total tailings after accurate reduction of the fineness of the second-stage ball mill: The fineness of the second-stage ball mill was reduced, and the difference in copper content between the re-selected tailings and the under-screen tailings was used to increase the yield of coarse particles after scavenging tailings classification, and the change in copper content in the total tailings was determined. The results are shown in Table 9. The difference in copper content between the re-selected tailings and the under-screen tailings when the grinding fineness was 77.8% was 0.051 percentage points, which was between 0.04 and 0.06 percentage points.

[0081] Table 9 Changes in copper content in total tailings

[0082]

[0083] Note: The operating yield corresponds to the scavenging tailings.

[0084] d) Determine the optimal second-stage ball milling fineness range: as the second-stage ball milling fineness gradually decreases from the highest second-stage ball milling fineness of -0.045 mm accounting for 77.8% when the actual optimal copper content of the total tailings is reached, the copper content of the total tailings first stabilizes and then gradually increases. At this time, -0.045 mm accounts for 72.3%, that is, D3 is the optimal second-stage ball milling fineness for the double flash copper slag.

[0085] The present invention determines the change curve of the influence of the second-stage ball milling fineness on the copper content of the total tailings through the copper particle loss law of the scavenging tailings in different front-end grinding processes of copper smelting slag, the influence of the second-stage ball milling fineness on the yield of coarse particles after scavenging tailings classification, and the difference in copper content between the re-selected tailings and the under-screen tailings. The curve can be used to obtain the optimal second-stage ball milling fineness range of the copper smelting slag of this nature that meets both technical and economic requirements; the present invention organically combines mathematical principles and industrial applications, and more conveniently predicts the second-stage ball milling fineness and the appropriate interval, which can respond quickly to on-site production adjustments; the present invention can obtain the theoretical and actual optimal total tailings copper content index when the copper smelting slag of this nature adopts an efficient separation process according to different actual conditions, which has important guiding significance for production; the present invention searches and determines the optimal second-stage ball milling fineness through two stages, makes full use of the difference in fine grinding efficiency between the ball mill and the vertical mill, significantly reduces the comprehensive energy consumption of grinding, and has important guiding significance for on-site production cost reduction and efficiency improvement.

[0086] Those skilled in the art should be aware that the protection scheme of the present invention is not limited to the above-mentioned embodiments, and various arrangements, combinations and transformations can be performed on the basis of the above-mentioned embodiments. Without violating the spirit of the present invention, various transformations of the present invention fall within the protection scope of the present invention.

Claims

1. A method for determining the fineness of two-stage ball milling in a copper smelting slag efficient separation process, characterized in that The steps include: S1, determine the particle size composition of flotation tailings after the fineness of the second-stage ball milling is accurately increased, continuously improve the fineness of the second-stage ball milling, determine the particle size of the scavenging tailings obtained by the second-stage ball milling with different finenesses, and determine the second-stage ball milling fineness D1 when the copper content of the finest particle size in the scavenging tailings is in a stable range; S2, determine the actual optimal copper content index of the total tailings under the fineness D1, and classify the scavenging tailings under the fineness D1. The fine particles are the under-screen tailings, and the coarse particles are re-grinded and re-selected to obtain the re-selected tailings. At this time, the copper grade of the total tailings is calculated as follows: Among them, β 总 is the copper grade of the total tailings; γ 再选 The re-selected tailings yield is obtained after the coarse tailings on the screen are regrinded and re-selected after the scavenged tailings are classified; β 再选 The copper grade of the re-selected tailings obtained after the coarse tailings on the sieve are sized and re-grinded; γ 筛下 It is the yield of fine tailings after scavenging tailings classification; β 筛下 The copper grade of fine particles in the tailings after scavenging tailings classification; S3, determination of copper content in different tailings after the fineness of the second-stage ball mill is precisely reduced: the fineness of the second-stage ball mill is reduced from D1, and the difference in copper content between the re-selected tailings and the under-screen tailings is used to improve the yield of coarse particles after scavenging tailings classification, determine the change in copper content in the total tailings, and compare the difference in copper content between the re-selected tailings and the under-screen tailings at D1; S4, determine the best second-stage ball milling fineness range. As the second-stage ball milling fineness decreases from D1, when the difference between the copper content of the re-selected tailings and the copper content of the under-screen tailings at D1 is higher than 0.06 percentage points, the copper content of the re-selected tailings and the total tailings will first reach a theoretical minimum value lower than the actual minimum value. At this time, the second-stage ball milling fineness is D2. Then the second-stage ball milling fineness continues to decrease, and the total tailings copper content increases to the actual minimum value. At this time, the second-stage ball milling fineness is D2. The ore fineness is D3, and the range of D2 to D3 is the optimal second-stage ball milling fineness range; when the difference between the copper content in the re-selected tailings and the copper content in the under-screen tailings at D1 is between 0.04 and 0.06 percentage points, the theoretical minimum value of the total copper tailings is not obvious, and D3 is taken as the optimal second-stage ball milling fineness; when the difference between the copper content in the re-selected tailings and the copper content in the under-screen tailings at D1 is less than 0.04 percentage points, D1 is taken as the optimal second-stage ball milling fineness.

2. The method for determining the fineness of the second-stage ball milling in the efficient separation process of copper smelting slag according to claim 1 is characterized by: In step S1, the finest particle size of the scavenged tailings is 0.045 mm or 0.038 mm.

3. The method for determining the fineness of the second-stage ball milling in the copper smelting high-efficiency separation process according to claim 1 or 2, characterized in that In step S2, the re-grinding fineness of the tailings on the screen is -0.038 mm, accounting for 96% to 99%.

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