Use of lignosulfonate as a binder in a nickel-iron concentrate dry powder forming process, nickel-iron concentrate dry powder forming process

Abstract

The application relates to the technical field of metallurgical engineering materials, and specifically discloses application of a lignosulfonate as a binder in a dry powder forming process of a nickel-iron concentrate and the dry powder forming process of the nickel-iron concentrate. The forming method specifically comprises the following steps: adding the lignosulfonate as the binder into the dry powder of the nickel-iron concentrate, and adopting roll forming. The lignosulfonate is used as the binder in the dry powder forming of the dry nickel-iron concentrate after drying, the prepared green block has high strength, and the production requirements can be met.

Description

Technical Field

[0001] This application relates to the technical field of metallurgical engineering materials, and more specifically, to the application of a lignin sulfonate as a binder in the nickel-iron concentrate dry powder forming process, and the nickel-iron concentrate dry powder forming process. Background Technology

[0002] In traditional iron concentrate molding processes, bentonite, hydrated lime, phosphate, starch, and sodium humate are commonly used as molding binders. However, traditional molding processes require the addition of 7-13% water to ensure that the added binder is fully dissolved in the water and thus fully dispersed in the iron concentrate, thereby maximizing the binding performance of the molding binder.

[0003] The nickel-iron concentrate obtained after grinding and beneficiation is dried and then pressed into briquettes. The raw material for briquetting contains very little moisture (≤4%). Common inorganic and organic binders, such as bentonite, CMC (methyl methacrylate), and sodium humate, are used. However, because these binders cannot fully dissolve in water and are not sufficiently dispersed in the dry concentrate powder, their binding properties are not fully utilized, resulting in briquettes with very low strength that cannot meet the requirements of subsequent smelting production. However, if the nickel-iron concentrate obtained after grinding and beneficiation is directly briquetted without drying, the high moisture content (up to 12%) in the raw material causes severe roller sticking during briquetting, leading to difficulties in the actual production process.

[0004] Researchers have used a mixture of various binders and added them to nickel-iron concentrate dry powder for briquetting. When the amount of mixed binder added was 5%, it was still impossible to prepare green briquettes that met the production requirements. When the amount of added binder was increased to 8%, the strength of the green briquettes reached the production index, but at the same time, the production cost was also increased.

[0005] When using bentonite as a binder, it is added to the dried nickel-iron concentrate powder at a weight of 3-5%. After mixing, the two are pressed into briquettes using a roller briquetting machine. Because the moisture content of the dried nickel-iron concentrate is very low (≤4%), the bentonite cannot fully absorb moisture and swell, thus failing to form a fibrous structure and fully exert its binding properties. The drop strength of the raw briquettes is only 1-3 times / 0.5m.

[0006] When using organic binders such as CMC, 1-3% of the weight of the nickel-iron concentrate is added to the dried nickel-iron concentrate powder. After mixing, the mixture is pressed into briquettes using a roller briquetting machine. Because the moisture content of the dried nickel-iron concentrate is very low, only a small portion of the organic binder dissolves in water. Only a portion of the -COOH and -OH groups undergo deprotonation and chemical adsorption on the mineral surface, thus the binding performance is not fully realized. When the CMC addition is 1%, the drop strength of the green briquettes is only 2.4 times / 0.5m; when the addition increases to 3%, the drop strength increases to 5.3 times / 0.5m. However, the market price of CMC (approximately 8500 yuan / ton) is much higher than that of bentonite (approximately 300 yuan / ton), resulting in higher production costs.

[0007] When using a composite organic binder such as sodium humate, it is added to the dried nickel-iron concentrate powder at 1-5% of its weight. After mixing, the powder is pressed into briquettes using a roller briquetting machine. Because the moisture content of the dried nickel-iron concentrate is very low, only a small portion of the organic components in the binder dissolves in the water. Only a portion of the -COOH and -OH groups undergo deprotonation and chemical adsorption on the mineral surface, thus the binding performance is not fully realized. When the sodium humate content is 2%, the drop strength of the green briquettes is only 1.5 drops / 0.5m; when the content increases to 5%, the drop strength is only 2.9 drops / 0.5m, which fails to meet production requirements.

[0008] Therefore, it is necessary to find a binder that can be used as a binder for the molding of dried nickel-iron concentrate powder, so that the strength of the resulting green blocks meets the production requirements. Summary of the Invention

[0009] This application provides an application of lignin sulfonate as a binder in the forming process of dry nickel-iron concentrate, and a forming process for dry nickel-iron concentrate. By utilizing lignin sulfonate as a binder in the forming of dried nickel-iron concentrate, this application yields green lumps with high strength, meeting production requirements.

[0010] In one aspect, this application provides the application of lignin sulfonate as a binder in the forming process of dry nickel-iron concentrate.

[0011] Optionally, the lignin sulfonate includes, but is not limited to, sodium lignin sulfonate and calcium lignin sulfonate.

[0012] In related technologies, if the raw materials for the nickel-iron concentrate dry powder forming process are dried, their moisture content is low, which is not conducive to the commonly used binders fully exerting their bonding performance, resulting in green lumps with low strength that cannot meet production requirements. If the raw materials for the nickel-iron concentrate dry powder forming process are not dried, their moisture content is too high. Although the binder can fully exert its bonding performance, severe roller sticking will occur during the forming process, leading to production disruptions.

[0013] This application selects lignin sulfonate as a binder in the dry powder forming process of dried nickel-iron concentrate, resulting in green briquettes with high strength that meets production requirements. Compared to commonly used binders such as bentonite, CMC, and sodium humate, lignin sulfonate exhibits strong dispersibility, dispersing fully in a small amount of water and adsorbing onto the surface of mineral particles. Furthermore, due to the presence of numerous active groups in its structure, it can undergo chelation or coordination chemical reactions with the hydroxylated mineral particle surface, thus tightly adsorbing onto the mineral particle surface and generating strong adhesion, thereby achieving the dry powder forming of nickel-iron concentrate. The technical solution of this application, on the one hand, provides a new application method for lignin sulfonate; on the other hand, it solves the problem that current binders are unsuitable for the dry powder forming process of nickel-iron concentrate.

[0014] Secondly, this application provides a nickel-iron dry powder forming process, which adopts the following technical solution:

[0015] A process for forming dry nickel-iron concentrate, the forming process specifically includes the following steps: adding lignin sulfonate as a binder to the dry nickel-iron concentrate, and forming it using rollers.

[0016] Optionally, the amount of lignin sulfonate added is 2-4% of the weight of the raw material used for nickel-iron concentrate forming.

[0017] Optionally, the amount of lignin sulfonate added is 2.5-3.5% of the weight of the raw material used for nickel-iron concentrate forming.

[0018] In one specific embodiment, the amount of lignin sulfonate added can be 2%, 2.5%, 3%, 3.5%, or 4% of the weight of the raw material used for nickel-iron concentrate forming.

[0019] In some specific embodiments, the amount of lignin sulfonate added can be 2-2.5%, 2-3%, 2-3.5%, 2.5-3%, 2.5-3.5%, 2.5-4%, 3-3.5%, 3-4%, or 3.5-4% of the weight of the raw material used for nickel-iron concentrate forming.

[0020] Optionally, the moisture content in the nickel-iron concentrate dry powder is ≤4%.

[0021] Optionally, the moisture content of the nickel-iron concentrate dry powder is ≥1%.

[0022] In one specific embodiment, the moisture content in the nickel-iron concentrate powder can be 0.5%, 1%, 2%, 2.5%, 3%, 3.5%, or 4%.

[0023] In some specific embodiments, the moisture content in the nickel-iron concentrate powder can be 0.5-1%, 0.5-2%, 0.5-2.5%, 0.5-3%, 0.5-3.5%, 0.5-4%, 1-2%, 1-2.5%, 1-3%, 1-3.5%, 1-4%, 2-2.5%, 2-3%, 2-3.5%, 2-4%, 2.5-3%, 2.5-3.5%, 2.5-4%, 3-3.5%, 3-4%, 3.5-4%.

[0024] Thirdly, this application provides a green block obtained by the above molding method, wherein the green block has a drop strength of 4.5 times / 0.5m or more and a compressive strength of 80N / piece or more.

[0025] In summary, this application has the following beneficial effects:

[0026] 1. This application selects lignin sulfonate as a binder in the dry powder forming process of dried nickel-iron concentrate, resulting in green lumps with high strength that meets production requirements. Compared to commonly used binders such as bentonite, CMC, and sodium humate, lignin sulfonate has strong dispersibility, allowing it to disperse fully in a small amount of water and adsorb onto the surface of mineral particles. Furthermore, due to the presence of numerous active groups in its structure, it can undergo chelation or coordination chemical reactions with the hydroxylated mineral particle surface, thus tightly adsorbing onto the mineral particle surface and generating strong adhesion, thereby achieving the dry powder forming of nickel-iron concentrate.

[0027] 2. The technical solution of this application provides a new application method for lignin sulfonate and solves the problem that current binders are not suitable for the forming process of nickel-iron concentrate dry powder.

[0028] 3. Using lignin sulfonate as a binder, it is added at 2-4% of the weight of nickel-iron concentrate to the dry nickel-iron concentrate raw material with a moisture content of less than 4%, and then mixed evenly. The mixture is then formed using a roller briquetting machine. The resulting green briquettes have high strength and can meet production requirements.

[0029] 4. Furthermore, the market price of lignin sulfonate binders is 1250 yuan / ton, far lower than the market price of CMC. While meeting the strength requirements for production, the cost is within an acceptable range for manufacturers. Detailed Implementation

[0030] This application selects lignin sulfonate as a binder in the molding process of dried nickel-iron concentrate powder, resulting in green briquettes with high strength that meets production requirements. On the one hand, this provides a new application method for lignin sulfonate; on the other hand, it solves the problem that current binders are not suitable for the molding process of nickel-iron concentrate powder.

[0031] Among them, lignin sulfonates include, but are not limited to, sodium lignin sulfonate and calcium lignin sulfonate.

[0032] This application also provides a process for forming dry nickel-iron concentrate. The forming process specifically includes the following steps: adding lignin sulfonate as a binder to dry nickel-iron concentrate with a moisture content of ≤4% at a weight ratio of 2-4% and mixing evenly; and forming the mixture by using a roller briquetting machine.

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results.

[0035] Example

[0036] Example 1

[0037] This embodiment provides a process for forming dry nickel-iron concentrate.

[0038] The specific steps of this preparation method are as follows:

[0039] According to the parameters shown in Table 1, the molding process specifically includes the following steps: adding lignin sulfonate as a binder to the dry nickel-iron concentrate powder and mixing it evenly; molding the mixture through a roller briquetting machine to obtain raw briquettes.

[0040] Table 1. Addition of each raw material and strength test results in the molding process of Examples 1-14 and Comparative Examples 1-3.

[0041]

[0042] Example 2-13

[0043] Examples 2-13 provide a molding process for nickel-iron concentrate dry powder. The difference between the above molding processes and Example 3 lies in the amount of binder added and the moisture content of the nickel-iron concentrate dry powder, as shown in Table 1.

[0044] Example 14

[0045] This embodiment provides a process for forming dry nickel-iron concentrate. The difference between this forming process and Example 3 is that the added binder is calcium lignosulfonate, as shown in Table 1. The remaining steps are the same as in Example 3.

[0046] Comparative Example

[0047] Comparative Example 1

[0048] Comparative Example 1 provides a process for forming dry nickel-iron concentrate. The difference between the above forming process and Example 3 is that the binder added is bentonite (purchased from Changxing Metallurgical Casting Materials Co., Ltd., sodium-based bentonite), as shown in Table 1. The remaining steps are the same as in Example 3.

[0049] Comparative Example 2

[0050] Comparative Example 2 provides a process for forming dry nickel-iron concentrate. The difference between the above forming process and Example 3 is that the binder added is CMC (purchased from Nanjing Liangyou Chemical Co., Ltd., mineral processing grade CMC), as shown in Table 1. The remaining steps are the same as in Example 3.

[0051] Comparative Example 3

[0052] Comparative Example 3 provides a process for forming dry nickel-iron concentrate. The difference between this forming process and Example 3 is that the added binder is sodium humate (purchased from Wuhan Kanos Technology Co., Ltd., with a humic acid content of over 50%), as shown in Table 1. All other steps are the same as in Example 3.

[0053] Performance testing

[0054] The drop strength and compressive strength of the raw blocks obtained in the above embodiments and comparative examples were tested. The test results are shown in Table 1.

[0055] The detection method is as follows:

[0056] (1) Drop strength test method: The block to be tested is dropped freely from a height of 0.5m onto the steel plate directly below, and this is repeated several times until the block cracks. Ten blocks to be tested are tested according to the above method, and the average number of drops of the ten blocks is taken as the drop strength of the block to be tested.

[0057] (2) Compressive strength testing method: The compressive strength was measured using a digital display compressive strength testing machine. The average compressive strength of ten raw blocks was taken as the compressive strength of the block to be tested.

[0058] As shown in Table 1, comparing the test results of Example 3 and Comparative Examples 1-3, it is evident that using lignin sulfonate as a binder in this application significantly improves the drop strength and compressive strength of the green lumps compared to using bentonite and sodium humate as binders. Furthermore, although the drop strength and compressive strength of the green lumps using CMC as a binder are also higher than those using bentonite and sodium humate, the higher cost of CMC makes it less than the optimal choice. This application utilizes lignin sulfonate as a binder for molding dried nickel-iron concentrate powder, resulting in green lumps with high strength that meets production requirements.

[0059] Comparing the test results of Examples 1-5, it can be seen that when the amount of lignin sulfonate added accounts for 2-4% of the raw material weight of nickel-iron concentrate for forming, it can improve the drop strength and compressive strength of green lumps. In particular, when the amount of lignin sulfonate added accounts for 2.5-3.5% of the raw material weight of nickel-iron concentrate for forming, the drop strength and compressive strength of green lumps are significantly higher than those when the amount of lignin sulfonate added accounts for 2% of the raw material weight of nickel-iron concentrate for forming. Furthermore, since the drop strength and compressive strength of green lumps are not significantly different when the addition amount of lignin sulfonate accounts for 4% of the raw material weight of nickel-iron concentrate forming compared with the addition amount of lignin sulfonate accounting for 3.5% of the raw material weight of nickel-iron concentrate forming, this application preferably controls the addition amount of lignin sulfonate within the range of 2.5-3.5% of the raw material weight of nickel-iron concentrate forming, taking into account both economic benefits and green lump strength. The test results of Examples 9 and 12-13 of this application also verify the above conclusion.

[0060] Comparing the test results of Examples 3 and 6-11, it can be seen that when the moisture content of the nickel-iron concentrate powder is ≤4%, the drop strength of the resulting green lumps is greater than 4.5 drops / 0.5m, and the compressive strength is greater than 80N / lump. However, when the moisture content of the nickel-iron concentrate powder is <1%, the drop strength of the resulting green lumps is less than 4.5 drops / 0.5m, and the compressive strength is less than 80N / lump. Therefore, this application further selects nickel-iron concentrate powder with a moisture content of ≥1% and ≤4%, and uses lignin sulfonate as a binder for molding.

[0061] By comparing the test results of Example 7 and Example 14, it can be seen that the lignin sulfonate in the technical solution provided in this application can be sodium lignin sulfonate or calcium lignin sulfonate.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A process for forming dry nickel-iron concentrate, characterized in that, The molding process specifically includes the following steps: lignin sulfonate... It is added as a binder to dry nickel-iron concentrate powder and formed by roller molding. The amount of lignin sulfonate added is 3-4% of the weight of the raw material used for nickel-iron concentrate forming; 2% ≤ Moisture content in the dry nickel-iron concentrate powder ≤ 4%; The lignin sulfonate includes sodium lignin sulfonate and calcium lignin sulfonate; The green blocks produced using the molding process have a drop strength of 5.4 times / 0.5m or more and a compressive strength of 85N / piece or more.

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