Copper tailings-based volcanic ash pellets, preparation method and cement

Abstract

The present application discloses a copper tailings-based volcanic ash pellet, a preparation method and cement; it relates to the technical field of copper tailings utilization; the copper tailings-based volcanic ash pellet is prepared from the following components in weight percentage: copper tailings: 95-99wt%; limestone powder: 0.6-2.4wt%; fly ash: 0.2-2wt%; attapulgite: 0.2-0.6wt%. It is prepared by the following steps: S1, preparation of external materials; S2, intermittent balling; S3, continuous balling; S4, screening. By preparing copper tailings-based volcanic ash pellets with small particle size and high water content by balling, the problems of inconvenient feeding, uneven dispersion and easy accumulation in the preparation of cement can be well solved; the attapulgite can absorb a certain amount of water in the copper tailings, bond with limestone powder, fly ash and a small amount of copper tailings to form a mother ball that is resistant to fragmentation, and then bond more copper tailings on the outer layer to form a ball with better rolling performance.

Description

Technical Field

[0001] The present application relates to the technical field of copper tailings utilization, and in particular to copper tailings-based volcanic ash pellets, a preparation method and cement. Background Art

[0002] Copper tailings are a type of tailings left after copper ore is beneficiated. They are mostly in the form of fine particles or powder and are an inevitable product of copper mining and processing.

[0003] The treatment and utilization of copper tailings is an important environmental and economic issue. On the one hand, a large amount of accumulated copper tailings occupies land resources; on the other hand, the useful components in the copper tailings that are not fully recovered also have the value of reuse. Therefore, how to effectively treat copper tailings, reduce its impact on the environment, and recycle the valuable components in it as much as possible has become one of the important research directions of mine environmental protection and comprehensive resource utilization.

[0004] In recent years, with the improvement of environmental awareness and the advancement of technology, people have begun to explore various methods for the treatment and utilization of copper tailings; however, most of them are aimed at the reuse of copper tailings with larger particle sizes, at least copper tailings with a particle size of more than 1mm, as admixtures for some building materials. However, copper tailings with smaller particle sizes are very difficult to utilize. Summary of the invention

[0005] In order to solve at least one of the above technical problems, a method for recycling small-size copper tailings is developed. The present application provides copper tailings-based volcanic ash pellets, a preparation method and cement.

[0006] On the one hand, the present application provides a copper tailings-based volcanic ash pellet, which is prepared from the following components in weight percentage:

[0007] Copper tailings: 95~99wt%;

[0008] Limestone powder: 0.6-2.4wt%;

[0009] Fly ash: 0.2-2wt%;

[0010] Attapulgite: 0.2~0.6wt%.

[0011] Through the above technical scheme, attapulgite is added, so that the attapulgite can absorb a certain amount of moisture in the copper tailings, and bond with limestone powder, fly ash and a small amount of copper tailings to form a granular core, and then a mother ball is formed under the action of a ball-making machine, and attapulgite, limestone powder, fly ash and more copper tailings are continuously bonded on the outer layer to form a ball with the mother ball as the core; the mother ball has a stronger anti-fragmentation performance, making the copper tailings-based volcanic ash pellets not easy to break; the balls have better rolling performance and will not be difficult to disperse due to excessively strong adhesion.

[0012] Optionally, it comprises a mother ball and a ball-forming layer, wherein the ball-forming layer is wrapped around the outside of the mother ball; and the water content of the ball-forming layer is lower than the water content of the mother ball.

[0013] Through the above technical solution, the mother ball has a higher water content, which can have better bonding performance and improve the anti-fragmentation performance of the mother ball; the ball-forming layer has a lower water content, which can ensure better rolling performance.

[0014] Optionally, the particle size is between 0.1 and 5 mm.

[0015] Optionally, the weight ratio of the copper tailings to attapulgite is 162 to 240:1.

[0016] Optionally, the water content of the copper tailings is 14%.

[0017] Optionally, the particle size of the attapulgite is 0.2 to 5 μm.

[0018] In a second aspect, the present application provides a method for preparing the above-mentioned copper tailings-based volcanic ash pellets, comprising the following steps:

[0019] S1. Preparation of external materials

[0020] Mixing limestone powder, fly ash and attapulgite according to the formula to obtain an additional material;

[0021] S2, intermittent ball making

[0022] Add the copper tailings and the external materials into a cylindrical pelletizing machine, add 5-10% of water relative to the total weight of the copper tailings and the external materials, and perform rolling compaction to obtain mother balls;

[0023] S3, continuous ball making

[0024] Continue to add copper tailings to the cylindrical ball making machine, and add 3-5% water of the weight of the copper tailings added this time, continue to make balls, and wrap a ball-forming layer on the outside of the mother ball to make balls;

[0025] S4. Screening

[0026] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0027] Through the above technical scheme, small-particle copper tailings with high water content and external materials (limestone powder, fly ash, attapulgite) are added to the cylindrical pelletizer at one time, a certain amount of water is added, and the equipment is turned on to allow the materials to continuously agglomerate and grow inside; the growth of the mother ball of intermittent pelletizing is mainly based on agglomeration growth, and layer growth is secondary; when the mother ball rolls and compacts in the pelletizer, the capillary water between the particles is squeezed to the surface of the mother ball to form an over-wet layer. Because no new materials are added, the growth of the mother ball depends on the agglomeration of two or more mother balls, as well as the fragments of the broken small balls when the mother ball agglomerates in motion; in addition, the small balls grow by agglomerating with the mother ball, and some of the powder that is ground off is absorbed by other mother balls and grows in layers; the particle size of the balls in this step is large and the ball formation rate is low, and it is mainly to produce mother balls to prepare for the next step of continuous pelletizing.

[0028] After the mother ball is prepared, copper tailings and a certain amount of water are added, and the mother ball continues to grow mainly in layers; the mother ball is constantly rolled and compacted in the ball making machine, causing changes in the capillary shape and size, so that excess capillary water is transferred to the surface of the mother ball. The wet mother ball can easily stick to a layer of wet material with a lower degree of wetness during rolling, and then compacted, and another layer of wet material sticks to the surface. This is repeated many times, and the mother ball continues to grow until the friction in the mother ball is greater than the mechanical compaction force during rolling.

[0029] Optionally, the weight of the copper tailings placed in S3 is lower than the weight of the copper tailings placed in S2.

[0030] In a third aspect, the present application provides a cement prepared from the above-mentioned copper tailings-based volcanic ash pellets.

[0031] In summary, the present invention has at least one of the following beneficial effects:

[0032] 1. By preparing copper tailings with small particle size and high water content into copper tailings-based volcanic ash pellets through ball making, the problems of inconvenient feeding, uneven dispersion and easy accumulation in cement preparation can be well solved;

[0033] 2. By adding attapulgite, the attapulgite can absorb a certain amount of moisture in the copper tailings, and bond with limestone powder, fly ash and a small amount of copper tailings to form a granular core, and then form a mother ball under the action of a ball-making machine, and continuously bond attapulgite, limestone powder, fly ash and more copper tailings on the outer layer to form a ball with the mother ball as the core; the mother ball has a stronger anti-fragmentation performance, making the copper tailings-based volcanic ash pellets not easy to break; the ball has better rolling performance and will not be difficult to disperse due to excessive adhesion;

[0034] 3. The copper tailings-based volcanic ash pellets prepared by the present invention have qualified rolling properties and excellent impact resistance to fracture index, which can facilitate uniform mixing with other admixtures for preparing cement during the cement preparation process, and have high impact strength and are not easy to break, so that the prepared cement has good uniformity and high strength, and small-particle copper tailings can be used in cements of various grades. DETAILED DESCRIPTION

[0035] The present application is further described in detail below in conjunction with embodiments.

[0036] In the following examples of the present application, the main components involved, unless otherwise specified, were purchased from commercially available products.

[0037] Copper tailings: from Tongguan Lujiang Mining Company;

[0038] Limestone powder: <1mm, from Tongling Hongyun Calcium Industry Co., Ltd.;

[0039] Fly ash: Class F II fly ash, fineness 15.0%, water requirement ratio 98%, loss on ignition 3.8%;

[0040] Attapulgite 0.2~5μm. Specific embodiments

[0042] Example 1

[0043] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0044] 2.4 kg of limestone powder, 2.0 kg of fly ash and 0.6 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0045] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0046] 45 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0047] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0048] Example 2

[0049] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0050] 2.0 kg of limestone powder, 1.5 kg of fly ash and 0.5 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0051] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0052] 46 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0053] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0054] Example 3

[0055] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0056] 1.6 kg of limestone powder, 1.0 kg of fly ash and 0.4 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0057] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0058] 47 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0059] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0060] Example 4

[0061] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0062] 1.2 kg of limestone powder, 0.5 kg of fly ash and 0.3 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0063] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0064] 48 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0065] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0066] Example 5

[0067] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0068] 0.6 kg of limestone powder, 0.2 kg of fly ash and 0.26 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0069] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0070] 49 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0071] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0072] The rolling property and impact anti-fragmentation index of the copper tailings-based volcanic ash pellets prepared in the above Examples 1 to 5 were measured, as shown in Table 1; other properties of the copper tailings-based volcanic ash pellets meet the relevant requirements of the standard (GB / T2847-2022 Volcanic ash mixed materials used in cement).

[0073] Rolling property measurement: prepare a steel plate with a smooth surface, the length of which is 1 m, and the width and thickness are not limited as long as they do not affect the use, and keep it horizontal; take out 1 kg of the copper tailings-based volcanic ash pellets prepared in the same embodiment at random, and place them on one side of the steel plate along the length direction, now raise one side of the length of the steel plate by 1 cm, tilt the steel plate, and roll it to the other side, catch the rolled copper tailings-based volcanic ash pellets with a container on the other side, and record the weight m of the copper tailings-based volcanic ash pellets falling into the container, if m≥0.95, the rolling property of the copper tailings-based volcanic ash pellets prepared in this embodiment is evaluated as excellent; if 0.95>m≥0.85, the rolling property of the copper tailings-based volcanic ash pellets prepared in this embodiment is evaluated as qualified; otherwise, the rolling property is judged as unqualified.

[0074] Determination of impact anti-fragmentation index: 100 copper tailings-based volcanic ash pellets prepared in the same embodiment are randomly taken out and dropped from a height of 1 m onto a cement floor. The number n of copper tailings-based volcanic ash pellets that are not loosened or broken is counted. If n≥95, the impact anti-fragmentation index of the copper tailings-based volcanic ash pellets prepared in this embodiment is evaluated to be up to standard; otherwise, the impact anti-fragmentation index is unqualified.

[0075] Table 1

[0076]

[0077]

[0078] It can be seen from Examples 1 to 5 and Table 1 of the present application that the copper tailings-based volcanic ash pellets prepared in the present application meet the relevant requirements of the standard (GB / T2847-2022 Volcanic ash mixed materials for cement) in other properties, and the rolling property and impact resistance index meet the qualified requirements; the qualified rolling property can facilitate the feeding, and it is easier to mix with other materials when preparing cement, and the uniformity is higher. The qualified impact resistance index can meet the high strength of the copper tailings-based volcanic ash pellets when preparing cement, and will not break, and it is not easy to cause the local performance of cement to deteriorate.

[0079] By analyzing the parameters in Table 1, it can be seen that the performance of Examples 2 to 3 is better than that of other examples. The inventors prepared the following Examples 6 to 11 to further analyze the effect of the weight ratio of copper tailings to attapulgite on the performance of the copper tailings-based volcanic ash pellets prepared in the present application.

[0080] Among them, Examples 6 to 8 are based on Example 2, and only the amount of attapulgite added is changed to obtain technical solutions with different weight ratios of copper tailings to attapulgite, as shown in detail as follows.

[0081] Example 6

[0082] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0083] 2.0 kg of limestone powder, 1.5 kg of fly ash and 0.6 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0084] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0085] 46 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0086] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0087] Example 7

[0088] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0089] 2.0 kg of limestone powder, 1.5 kg of fly ash and 0.4 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0090] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0091] 46 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0092] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0093] Example 8

[0094] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0095] 2.0 kg of limestone powder, 1.5 kg of fly ash and 0.3 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0096] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0097] 46 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0098] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0099] The rolling property and impact anti-fragmentation index of the copper tailings-based volcanic ash pellets prepared in the above Examples 6 to 8 were measured, as shown in Table 2; other properties of the copper tailings-based volcanic ash pellets meet the relevant requirements of the standard (GB / T2847-2022 Volcanic ash mixed materials used in cement).

[0100] Table 2

[0101] Copper tailings-based volcanic ash pellets Copper tailings and attapulgite weight ratio Rollability Impact resistance index Example 6 160 qualified excellent Example 2 192 excellent excellent Example 7 240 excellent excellent Example 8 320 qualified excellent

[0102] It can be seen from Table 2 that in the technical scheme of the present application, the weight ratio of copper tailings to attapulgite has a significant effect on the performance of the copper tailings-based volcanic ash pellets prepared in the present application; and when the weight ratio of copper tailings to attapulgite is in the range of 162 to 240:1, the prepared copper tailings-based volcanic ash pellets have excellent rolling performance and a high impact resistance to fragmentation index, reaching the excellent standard.

[0103] Among them, Examples 9 to 11 are based on Example 3, and only the amount of attapulgite added is changed to obtain technical solutions with different weight ratios of copper tailings to attapulgite, as shown in detail as follows.

[0104] Example 9

[0105] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0106] 1.6 kg of limestone powder, 1.0 kg of fly ash and 0.6 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0107] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0108] 47 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0109] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0110] Example 10

[0111] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0112] 1.6 kg of limestone powder, 1.0 kg of fly ash and 0.5 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0113] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0114] 47 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0115] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0116] Embodiment 11

[0117] This embodiment is used to prepare a copper tailings-based volcanic ash pellet, and the specific preparation method is as follows.

[0118] 1.6 kg of limestone powder, 1.0 kg of fly ash and 0.3 kg of attapulgite were mixed according to the formula amount to obtain an additional material;

[0119] 50 kg of copper tailings and external materials were added into a cylindrical ball making machine, and 8 kg of water was added for rolling and compacting to obtain mother balls;

[0120] 47 kg of copper tailings are continuously added to the cylindrical ball making machine, and 1.5 kg of water is added to continue making balls, and a ball-forming layer is wrapped around the outside of the mother ball to obtain a ball;

[0121] The pellets are size-screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

[0122] The rolling property and impact anti-fragmentation index of the copper tailings-based volcanic ash pellets prepared in the above Examples 9 to 11 were measured, as shown in Table 3; other properties of the copper tailings-based volcanic ash pellets meet the relevant requirements of the standard (GB / T2847-2022 Volcanic ash mixed materials used in cement).

[0123] Table 3

[0124] Copper tailings-based volcanic ash pellets Copper tailings and attapulgite weight ratio Rollability Impact resistance index Example 9 162 excellent excellent Example 10 194 excellent excellent Example 3 243 qualified excellent Embodiment 11 323 qualified excellent

[0125] It can be seen from Table 3 that in the technical scheme of the present application, the weight ratio of copper tailings to attapulgite has a significant effect on the performance of the copper tailings-based volcanic ash pellets prepared in the present application; and when the weight ratio of copper tailings to attapulgite is in the range of 162 to 240:1, the prepared copper tailings-based volcanic ash pellets have excellent rolling performance and a high impact resistance to fragmentation index, reaching the excellent standard.

[0126] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A copper tailings-based volcanic ash pellet, characterized in that: It is prepared by including the following components in weight percentage: Copper tailings: 95~99wt%; Limestone powder: 0.6-2.4wt%; Fly ash: 0.2-2wt%; Attapulgite: 0.2~0.6wt%.

2. The copper tailings-based volcanic ash pellets according to claim 1, characterized in that: It comprises a mother ball and a ball-forming layer, wherein the ball-forming layer is wrapped around the outside of the mother ball; and the water content of the ball-forming layer is lower than that of the mother ball.

3. The copper tailings-based volcanic ash pellets according to claim 1, characterized in that: The particle size is 0.1~5mm.

4. The copper tailings-based volcanic ash pellets according to claim 1, characterized in that: The weight ratio of the copper tailings to attapulgite is 162-240:

1.

5. The copper tailings-based volcanic ash pellets according to claim 1, characterized in that: The water content of the copper tailings is 14%.

6. The copper tailings-based volcanic ash pellets according to claim 1, characterized in that: The particle size of the attapulgite is 0.2 to 5 μm.

7. A method for preparing copper tailings-based volcanic ash pellets according to claim 1, characterized in that: The following steps are involved: S1. Preparation of external materials Mixing limestone powder, fly ash and attapulgite according to the formula to obtain an additional material; S2, intermittent ball making Add the copper tailings and the external materials into a cylindrical pelletizing machine, add 5-10% of water relative to the total weight of the copper tailings and the external materials, and perform rolling compaction to obtain mother balls; S3, continuous ball making Continue to add copper tailings to the cylindrical ball making machine, and add 3-5% water of the weight of the copper tailings added this time, continue to make balls, and wrap a ball-forming layer on the outside of the mother ball to make balls; S4. Screening The pellets are sized and screened to obtain copper tailings-based volcanic ash pellets with a size of 0.1 to 5 mm.

8. The preparation method according to claim 7, characterized in that: The weight of the copper tailings placed in S3 is lower than the weight of the copper tailings placed in S2.

9. A cement, characterized in that: The invention is prepared from the copper tailings-based volcanic ash pellets described in claim 1.

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