A rapid estimation method for the sand settling yield of tailings cyclone

Abstract

The present invention discloses a method for rapidly estimating the sand settling yield of a tailings pond cyclone. By obtaining the preset sand settling coarse sand content of the tailings dam, obtaining the feed coarse sand content of the cyclone, and obtaining the preset cyclone classification efficiency value, the sand settling yield of the cyclone can be roughly calculated according to the formula. The present invention proposes a theoretical method for rapidly estimating the sand settling yield of the tailings pond, and can rapidly estimate the sand settling yield of the cyclone without conducting a cyclone test, and the error is small; at the same time, the coarse sand content in the cyclone overflow can also be rapidly estimated, so as to facilitate the determination of the slope of the tailings pond sedimentation beach. This rapid estimation method is mainly used for mid-line tailings ponds. In addition, it can also be used as a reference for estimating the sand settling yield of the cyclone in downstream tailings ponds or ore dressing operations.

Description

Technical Field

[0001] The invention relates to a method for estimating the sand settling yield, in particular to a method for quickly estimating the sand settling yield of a tailings pond cyclone. Background Art

[0002] Tailings ponds refer to places where dams are built to intercept valley mouths or enclosures to store tailings or other industrial waste discharged from metal or non-metal mines after ore sorting. There are many tailings ponds in my country, with the peak number approaching 13,000, accounting for more than half of the total number of tailings ponds in the world. In recent years, with my country's vigorous rectification of tailings ponds, especially the introduction of the "two limits" policy for tailings ponds (the height of tailings ponds shall not exceed 200m, and the number of tailings ponds will only decrease but not increase), the number of tailings ponds in my country has decreased significantly. As of the end of May 2020, there are still 7,278 tailings ponds in my country. Among these tailings ponds, upstream tailings ponds account for the vast majority of the number because of their convenient operation and management. As my country's regulatory policies on tailings ponds become stricter, mid-line tailings ponds are increasingly welcomed by enterprises and regulatory authorities because they are more stable and have a larger storage capacity under the same dam height conditions than upstream tailings ponds. The center-line tailings pond uses cyclones to separate coarse tailings for dam construction. The cyclone sand settling yield is a key factor affecting the dam construction of the center-line tailings pond. The cyclone sand settling yield generally needs to be determined through cyclone classification tests, which is not only time-consuming and labor-intensive, but also affects the progress of engineering design.

[0003] In view of this, it is necessary to propose a rapid estimation method for the sand settling yield of the tailings cyclone to solve the above defects. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for quickly estimating the sand settling yield of a tailings cyclone, aiming to solve the problem that the existing sand settling yield needs to be determined through a cyclone classification test, which is time-consuming and labor-intensive and often affects the progress of engineering design. To achieve the above purpose, the present invention provides a method for quickly estimating the sand settling yield of a tailings cyclone, and the estimation method comprises the steps of:

[0005] S1, obtain the preset coarse sand content β of tailings damming 沉 , get the coarse sand content of the cyclone feed β 给 ;

[0006] S2, according to the formula Calculate the theoretical maximum sand settling yield γ 沉max , where γ 沉max is the theoretical maximum sand settling yield, β 给 is the coarse sand content of the feed, β 沉 To preset the coarse sand content of sedimentation;

[0007] S3, obtaining a preset cyclone classification efficiency value η;

[0008] S4, according to the formula Calculate the actual sand settling rate γ of the hydrocyclone 沉 , where γ 沉 is the sand settling yield.

[0009] Preferably, the preset sedimentation coarse sand content β 沉 ≥75%.

[0010] Preferably, the preset cyclone classification efficiency value η is in the range of 70%≤η≤80%.

[0011] Preferably, the preset sedimentation coarse sand content β 沉 The preset cyclone classification efficiency value η is 75%. According to the formula γ 沉 =β 给 , calculate the actual sand settling rate γ of the hydrocyclone 沉 .

[0012] Preferably, the roughness rate θ of the cyclone is calculated according to the formula θ=100%-η; 溢 =100%-γ 沉 , calculate the overflow rate γ of the cyclone 溢 .

[0013] Preferably, according to the formula Calculation of overflow coarse sand content β 溢 , where γ 溢 is the overflow rate, β 溢 is the overflow coarse sand content.

[0014] Preferably, the preset sedimentation coarse sand content β 沉 The preset cyclone classification efficiency value η is 75%. According to the formula Calculation of overflow coarse sand content β 溢 .

[0015] Preferably, the estimated error range of the sand settling yield is ±3%.

[0016] Compared with the prior art, the method for quickly estimating the sand settling yield of a tailings pond cyclone provided by the present invention has the following beneficial effects:

[0017] The present invention provides a method for quickly estimating the sand settling yield of a tailings pond cyclone. By obtaining the preset sand settling coarse sand content of the tailings dam, obtaining the feed coarse sand content of the cyclone, and obtaining the preset cyclone classification efficiency value, the sand settling yield of the cyclone can be roughly calculated according to the formula. The present invention proposes a theoretical method for quickly estimating the sand settling yield of the tailings pond, which can quickly estimate the sand settling yield of the cyclone without conducting a cyclone test, and the error is small; at the same time, the coarse sand content in the cyclone overflow can also be quickly estimated to facilitate the determination of the slope of the tailings pond sedimentation beach. This quick estimation method is mainly used for mid-line tailings ponds, and can also be used as a reference for estimating the sand settling yield of cyclones in downstream tailings ponds or mineral processing operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0019] Figure 1 It is a schematic flow chart of a method for quickly estimating the sand settling yield of a tailings pond cyclone in one embodiment of the present invention;

[0020] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0021] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0024] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] Please refer to the attached Figure 1 The present invention provides a method for quickly estimating the sand settling yield of a tailings cyclone, the method comprising the steps of:

[0026] S1, obtain the preset coarse sand content β of tailings damming 沉 , get the coarse sand content of the cyclone feed β 给 ;

[0027] S2, according to the formula Calculate the theoretical maximum sand settling yield γ 沉max , where γ 沉max is the theoretical maximum sand settling yield, β 给 is the coarse sand content of the feed, β 沉 To preset the coarse sand content of sedimentation;

[0028] S3, obtaining a preset cyclone classification efficiency value η;

[0029] S4, according to the formula Calculate the actual sand settling rate γ of the hydrocyclone 沉 , where γ 沉 is the sand settling yield.

[0030] Specifically, for ease of description, the relevant terms appearing in the present invention are defined as follows, wherein the terms (5) to (12) are all expressed in percentages.

[0031] (1) Coarse sand: tailings particles with a particle size greater than or equal to 0.074 mm;

[0032] (2) Fine sand: tailings particles with a particle size less than 0.074 mm;

[0033] (3) Sand settling: tailings particles discharged from the sand settling port at the bottom of the cyclone, including coarse sand and fine sand;

[0034] (4) Overflow: Tailings particles discharged from the overflow port at the top of the cyclone, including coarse sand and fine sand;

[0035] (5) Grit yield γ 沉: The ratio of the mass of sand settling in the cyclone to the mass of tailings in the feed;

[0036] (6) Overflow yield γ 溢 : The ratio of the tailings mass in the cyclone overflow to the tailings mass in the feed;

[0037] (7) Theoretical maximum sand settling yield γ 沉max : The sand settling yield when all the coarse sand in the feed enters the sand settling, that is, the sand settling yield when there is no coarse sand in the overflow, which is the theoretical maximum sand settling yield;

[0038] (8) Preset cyclone classification efficiency value (i.e., separation efficiency) η: the ratio of the actual sand settling yield of the cyclone to the theoretical maximum sand settling yield, that is, the proportion of coarse sand in the feed separated by the cyclone into sand;

[0039] (9) Coarse sand rate θ: the proportion of coarse sand in the feed that is not separated by the hydrocyclone into the sediment, or the proportion of coarse sand in the feed that enters the overflow, coarse sand rate θ = 100% - preset hydrocyclone classification efficiency value η;

[0040] (10) Coarse sand content of feed β 给 =Ratio of the mass of coarse sand in the feed to the mass of all tailings particles in the feed;

[0041] (11) Grit content β 沉 =Ratio of the mass of coarse sand in the sediment to the mass of all tailings particles in the sediment;

[0042] (12) Overflow coarse sand content β 溢 = Ratio of the mass of coarse sand in the overflow to the mass of all tailings particles in the overflow

[0043] The following is a brief introduction to the derivation process of the formula for calculating the actual sand settling yield of the cyclone.

[0044] Specifically, according to Article 4.1.6, Paragraph 3 of the Code for Design of Tailing Facilities (GB50863-2013), “the content of coarse particles (d ≥ 0.074 mm) of tailings used for dam construction after downstream or mid-line tailings dam construction classification should not be less than 75%, and the content of particles with d ≤ 0.02 mm should not be greater than 10%”. For the convenience of calculation, here, the coarse sand for dam construction is set to 75% according to the content of coarse sand particles (d ≥ 0.074 mm) of tailings, that is, the preset coarse sand content of sedimentation is β 沉 =75%.

[0045] Assuming that the total mass of the cyclone feed is 100%, the mass of coarse sand is 40%, and the mass of fine sand is 60%, then the coarse sand content of the feed is β 给 =40%.

[0046] First, calculate the theoretical maximum sand settling yield, the process is as follows:

[0047] According to the above definition, the theoretical maximum sand yield is the sand yield when all the coarse sand in the feed enters the sand settling. At this time, the cyclone overflow does not contain any coarse sand, but only fine sand. Among the tailings calculated by the theoretical maximum sand yield, 75% is coarse sand and 25% is fine sand, that is, the preset coarse sand content β 沉 =75%, that is The theoretical maximum sand settling yield

[0048] Because the theoretical maximum sand yield = feed sand content / preset sand content, at this time, in theory, the preset cyclone classification efficiency value is 100%. It can be expressed as

[0049] The process of calculating the actual grit yield of the hydrocyclone is as follows:

[0050] It should be understood that for the actual operation of the cyclone, the theoretical maximum sand settling yield cannot be achieved during the cyclone production process, that is, it is impossible to ensure that the cyclone overflow does not contain coarse sand, and there will always be a part of the coarse sand that will flow into the overflow. Therefore, here it is assumed that coarse sand accounting for 10% of the total tailings in the feed enters the overflow.

[0051] It is worth noting that because the hydrocyclone has a problem of tailings classification or separation efficiency, the actual sand settling yield of the hydrocyclone is always lower than the theoretical maximum sand settling yield. The preset hydrocyclone classification efficiency value is the ratio of the actual sand settling yield of the hydrocyclone to the theoretical maximum sand settling yield. The preset hydrocyclone classification efficiency value represents the proportion of coarse sand in the feed that is separated into sand by the hydrocyclone. It should be known that most of the current preset hydrocyclone classification efficiency values ​​are 70% to 80%, so the preset hydrocyclone classification efficiency value is set to 75% here.

[0052] That is, the actual sand settling yield of the cyclone = the theoretical maximum sand settling yield × the preset cyclone classification efficiency value = the coarse sand content of the feed × the preset cyclone classification efficiency value / the preset coarse sand content of the sand settling, which can be expressed as:

[0053]

[0054] It should be understood that the present invention proposes a rapid estimation method for the theoretical sand settling yield of the tailings pond, which can quickly estimate the sand settling yield of the cyclone without conducting a cyclone test, and the error is small. This rapid estimation method is mainly used for mid-line tailings ponds. In addition, it can also be used as a reference for estimating the sand settling yield of the cyclone in downstream tailings ponds or mineral processing operations.

[0055] As a preferred embodiment of the present invention, the preset sedimentation coarse sand content β 沉 ≥75%. It should be understood that the preset grit content β沉 It can be selected and determined according to the actual situation or needs. According to the requirement of Article 4.1.6, Paragraph 3 of the Code for Design of Tailing Facilities (GB50863-2013), "the content of coarse particles (d ≥ 0.074 mm) of tailings used for dam construction after downstream or mid-line tailings dam construction classification should not be less than 75%, and the content of particles with d ≤ 0.02 mm should not be greater than 10%", preferably, in this embodiment, the preset coarse sand content is set to β 沉 ≥75%.

[0056] As a preferred embodiment of the present invention, the range of the preset cyclone classification efficiency value η is 70%≤η≤80%. It should be noted that the preset cyclone classification efficiency value η can be determined according to actual conditions or needs. Since most of the current preset cyclone classification efficiency values ​​are 70% to 80%, in this embodiment, the range of the preset cyclone classification efficiency value η is set to 70%≤η≤80%.

[0057] As a preferred embodiment of the present invention, the preset sedimentation coarse sand content β 沉 The preset cyclone classification efficiency value η is 75%. According to the formula γ 沉 =β 给 , calculate the actual sand settling rate γ of the hydrocyclone 沉 In detail, in this embodiment, when the preset sedimentation coarse sand content is set to 75% and the preset cyclone classification efficiency value is set to 75%, then That is, according to the formula γ 沉 =β 给 , calculate the actual sand settling rate γ of the hydrocyclone 沉 That is, the actual sand settling rate of the cyclone can be estimated according to the coarse sand content of the feed ore.

[0058] Further, according to the formula θ=100%-η, the roughness rate θ of the cyclone is calculated; according to the formula γ 溢 =100%-γ 沉 , calculate the overflow rate γ of the cyclone 溢 .

[0059] It should be understood that the coarse sand in the cyclone feed will not completely enter the grit, and a part of the coarse sand will always run into the overflow. The proportion of this part of coarse sand entering the overflow to the coarse sand in the feed is called the coarse sand running rate, and θ is used to represent the coarse sand running rate. The coarse sand running rate of the cyclone and the preset cyclone classification efficiency value are the proportions of the coarse sand in the feed entering the overflow and the grit respectively, that is, the coarse sand running rate + classification efficiency = 100%. Therefore, the coarse sand running rate θ of the cyclone can be calculated according to the formula θ = 100% - η.

[0060] It is worth noting that the overflow yield and the sand settling yield are the ratios of the tailings mass in the cyclone overflow and sand settling to the tailings mass in the feed, that is, overflow yield + sand settling yield = 100%. Therefore, according to the formula γ 溢 =100%-γ 沉 , calculate the overflow rate γ of the cyclone 溢 .

[0061] As a preferred embodiment of the present invention, according to the formula Calculation of overflow coarse sand content β 溢 , where γ 溢 is the overflow rate, β 溢 is the overflow coarse sand content.

[0062] It should be noted that the overflow coarse sand content is the ratio of the mass of coarse sand in the overflow to the mass of all tailings particles in the overflow. The overflow coarse sand content = feed coarse sand content × run-off rate / overflow yield rate. Combining the above two formulas for calculating run-off rate and overflow yield rate, the formula can be used to calculate Calculation of overflow coarse sand content β 溢 .

[0063] As a preferred embodiment of the present invention, the preset sedimentation coarse sand content β 沉 The preset cyclone classification efficiency value η is 75%. According to the formula Calculation of overflow coarse sand content β 溢 .

[0064] In detail, in this embodiment, the preset coarse sand content is set to 75%, and the preset cyclone classification efficiency value is set to 75%, then the roughness rate θ = 100% - 75% = 25%. At this time, according to the formula Calculation of overflow coarse sand content β 溢 .

[0065] Furthermore, the estimated error range of the grit yield is ±3%. It should be understood that the determination of the grit yield of the cyclone is a relatively complex issue, which is affected by many factors, including ore feeding factors, cyclone factors and cyclone placement factors, among which ore feeding factors include ore feeding particle size composition, ore feeding concentration, ore feeding pressure, ore feeding flow rate, etc., cyclone factors include cyclone diameter, cylinder column length, grit port and overflow port opening size, overflow pipe insertion depth, overflow pipe wall thickness, etc., cyclone placement factors include installation inclination, bottom flow discharge method, etc., in addition, tailings sampling and weighing calculation in grit also have a certain influence on the value of grit yield; preferably, in this embodiment, taking into account the above factors and the systematic and random errors in the test measurement process, the rapid estimation error of the grit yield of the cyclone in this embodiment can be set to ±3%. The "Design Specifications for Tailings Facilities" requires that the final finished product sand settling rate of the grading equipment and grading process should not be less than 1.2 times the maximum sand settling rate of each damming stage. Therefore, setting the estimated error of the cyclone sand settling rate to ±3% will not have a significant impact on the sand settling rate required for the actual damming operation and can meet production requirements.

[0066] The estimation method provided by the present invention can also quickly estimate the coarse sand content in the cyclone overflow, so as to facilitate the determination of the slope of the tailings pond sedimentation beach.

[0067] The present invention will be further described below in conjunction with examples, but the present invention is not limited to the following examples.

[0068] Example 1

[0069] As shown in Table 1, Table 1 is the cyclone tailings classification index during the production of a tailings pond in Jiangxi.

[0070] Table 1 Tailings classification index of a tailings pond in Jiangxi

[0071] project Eastern Grading System Western Grading System First stage feed + 0.074mm particle size content (%) 34.62 35.01 First stage sedimentation + 0.074mm particle size content (%) 71.44 72.07 First stage sand settling yield (%) 42.98 43.16 Second stage sand settling + 0.074mm particle size content (%) 85.33 85.2 Second stage sand settling yield (%) 49.65 49.3 Total sand settling yield (%) 21.34 21.07

[0072] The coarse sand content of a tailings pond in Jiangxi Province requires that the content of +0.074mm tailings particles should not be less than 85%, that is, β 沉 =85%. Due to the coarse sand content of the feed β 给 ≈35%, and the sand particle size requirement is relatively coarse, and the first stage classification of the cyclone cannot meet the particle size requirement, so the two-stage classification of the cyclone is adopted.

[0073] According to the above formula, the maximum theoretical sand settling rate of the hydrocyclone is Assuming that the estimated classification efficiency of the first and second cyclones is 75%, that is, η1 = η2 = 75%, the estimated comprehensive classification efficiency of the two cyclones is η = η1 × η2 = 75% × 75% ≈ 56%. Therefore, the actual total sand settling yield γ is estimated. 沉 =γ 沉max×η=41%×56%≈23%. The estimated result of the actual sand settling yield is close to about 21% of the total sand settling yield measured in Table 1.

[0074] In fact, the actual classification efficiency of the first stage cyclone in the Middle East classification system during the production process is shown in Table 1. Actual efficiency of the two-stage cyclone Actual comprehensive classification efficiency η of two-stage hydrocyclone * =88.7%×59.3%≈52.6%, the sand settling yield is calculated according to the actual comprehensive classification efficiency It is very close to the measured value.

[0075] The overflow coarse sand content β 溢 =β 给 ×(100%-η)÷γ 溢 =35%×(100%-85%)÷(100%-23%)≈6.8%.

[0076] Since the overflow from the first and second stages of the cyclone is discharged into the reservoir immediately after the operation of the corresponding cyclones, it is difficult to count the coarse sand content of the overflow. However, based on engineering experience, for example, the tailings entering a tailings pond in Hainan have a particle size of +0.074mm, accounting for about 8%, the average longitudinal slope of the sedimentary beach is about 0.5%, and the average slope of the sedimentary beach measured in a tailings pond in Jiangxi is 0.4% to 0.6%. It can be judged that the actual overflow coarse sand content is close to the calculated value of 6.8%.

[0077] Example 2

[0078] As shown in Table 2, Table 2 is the test indicators of a tailings pond in Sichuan.

[0079] Table 1 Index of cyclone classification test for a tailings pond in Sichuan

[0080] project Yield (%) +0.074mm particle size content (%) Feeding 100 51.18 Sand settling 65.9 75.13 overflow 34.1 3.14

[0081] A tailings pond in Sichuan is a newly built one. In order to determine the sand yield of the cyclone, a cyclone classification test was carried out. It is required that the coarse sand content of the tailings pond damming sand should not be less than 75%, that is, β 沉 =75%. The coarse sand content of the tailings entering the warehouse is the coarse sand content of the feed ore β 给 =51%, the tailings particle size is relatively coarse, therefore, the cyclone one-stage classification can meet the particle size requirements, so the cyclone one-stage classification method is adopted.

[0082] According to the formula, the maximum theoretical sand settling rate of the cyclone In Table 2, the cyclone sand settling yield β 沉 = 65.9%, close to the theoretical maximum sand settling yield of 68%, the classification efficiency of the cyclone in the experiment Also close to 100%.

[0083] Overflow coarse sand content β 溢 =β 给 ×(100%-η)÷γ 溢 =51%×(100%-97%)÷(100%-65.9%)≈4%. This is close to the overflow coarse sand content of 3.14% in Table 2.

[0084] In addition, in actual production, assuming that the cyclone classification efficiency is 75%, that is, η = 75%, the actual sand settling yield of the cyclone is γ 沉 =β 给 ≈51%, actual overflow coarse sand content of cyclone This needs to be verified after the tailings pond is put into operation.

[0085] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for quickly estimating the sand settling yield of a tailings cyclone, characterized in that: The estimation method comprises the steps of: S1, obtain the preset coarse sand content β of tailings damming 沉 , get the coarse sand content of the cyclone feed β 给 ; The preset sedimentation coarse sand content β 沉 ≥75%; S2, according to the formula Calculate the theoretical maximum sand settling yield γ 沉max , where γ 沉max is the theoretical maximum sand settling yield, β 给 is the coarse sand content of the feed, β 沉 To preset the coarse sand content of sedimentation; S3, obtaining a preset cyclone classification efficiency value η; the preset cyclone classification efficiency value η is in the range of 70%≤η≤80%; S4, according to the formula Calculate the actual sand settling rate γ of the hydrocyclone 沉 , where γ 沉 is the sand settling yield; According to the formula θ = 100% - η, calculate the roughness rate θ of the cyclone; according to the formula γ 溢 =100%-γ 沉 , calculate the overflow rate γ of the cyclone 溢 ; According to the formula Calculation of overflow coarse sand content β 溢 , where γ 溢 is the overflow rate, β 溢 is the overflow coarse sand content; The estimated error range of the grit yield is ±3%.

2. The method for rapidly estimating the sand settling yield of a tailings cyclone according to claim 1, characterized in that: The preset sedimentation coarse sand content β 沉 The preset cyclone classification efficiency value η is 75%. According to the formula γ 沉 =β 给 , calculate the cyclone sand yield γ 沉 .

3. The method for quickly estimating the sand settling yield of the tailings cyclone according to claim 2 is characterized in that: The preset sedimentation coarse sand content β 沉 The preset cyclone classification efficiency value η is 75%. According to the formula Calculation of overflow coarse sand content β 溢 .

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