Method for recycling mixed mineral powder in pellet production process in laboratory
By screening and drying mixed ore powders, and generating and roasting pellet ore, the problems of uneven particle size and adhesion waste in the laboratory are solved, efficient recycling and full mixing are achieved, and the quality indicators of blast furnace iron smelting are met.
Patent Information
- Application Number
- CN202411152563.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-21
- Publication Date
- 2024-12-27
AI Technical Summary
During the laboratory production of pellet ore, waste caused by uneven particle size and adhesion of mixed ore powder, there is a lack of effective recycling methods.
By screening and drying the mixed ore powder, a 10-16mm raw ball was generated, and the drop strength and compressive strength were tested, followed by drying, preheating and roasting treatment to achieve the recovery and full mixing of the mixed ore powder.
More than 20% of the pellet raw materials are effectively recovered, and the resulting pellet drop strength and compressive strength meet the qualified standards, meeting the quality requirements of blast furnace iron smelting.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of pellet production, and in particular relates to a method for recovering mixed ore powder in the process of producing pellets in a laboratory. Background Art
[0002] As the requirements for the grade of iron ore entering the blast furnace are increasing, and the ore dressing process provides a large amount of finely ground concentrate powder less than 0.074mm (-200 mesh). In order to use this concentrate powder economically and reasonably, steel practitioners have proposed a pelletizing method and have been widely used. The pellets are formed by rolling, with a diameter of 8-12mm or 9-16mm and uniform particle size; after high-temperature roasting and consolidation, they have high mechanical strength, which not only meets the requirements of the blast furnace smelting process, but also can withstand long-distance transportation and long-term storage. There are a large number of high-quality pellets prepared with magnetic concentrate in my country, which are matched with high-basicity sintered ore to form a reasonable charge structure, creating conditions for improving the technical and economic indicators of blast furnace production.
[0003] When preparing pellets in the laboratory, the particle size of the mother balls is often uneven. The usual practice is to manually screen out some of the mother balls, resulting in some waste. In addition, a large amount of mixed mineral powder will stick to the pelletizing disk during the pelletizing process. Tools are often used to manually scrape it off and pour it into a waste bucket, resulting in waste. Compared with the on-site, the laboratory does not have a device to recycle the mixed mineral powder and has higher requirements for the particle size of the pelletizing raw materials. Therefore, this part of the mixed mineral powder is not recycled but thrown away. Therefore, it is urgent to propose a new method for recycling mixed mineral powder in the process of making pellets in the laboratory. Summary of the invention
[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a method for recovering mixed ore powder in the process of producing pellets in a laboratory.
[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0006] The present invention provides a method for recovering mixed ore powder in a laboratory pellet production process, comprising the following steps:
[0007] (1) Pass the iron ore powder and bentonite binder through a 200-mesh sieve to control their particle size composition and mix them evenly.
[0008] (2) Spray water on the disc ball making machine to prepare 10-16 mm green balls, crush the excess mother balls and green balls with unqualified particle size, and remove the mixed mineral powder adhered to the disc and store it for recycling;
[0009] (3) Weighing the green balls with qualified particle size;
[0010] (4) Weighing the recovered mixed mineral powder and placing it in a drying box; drying the mineral powder to remove moisture while ensuring that the mineral powder does not react;
[0011] (5) Pass the dried mixed mineral powder through a 200-mesh sieve, take it out and make balls on a disc and spray water on it to produce green balls of 10-16 mm;
[0012] (6) Test the drop strength and compressive strength of the green balls in step (5).
[0013] (7) Drying, preheating and roasting the green balls prepared in step (5) to obtain finished oxidized pellets; the green ball drying conditions include: temperature of 130-150°C and time of 40-60 min; the preheating conditions include: temperature of 600-800°C and time of 10-15 min; the roasting conditions include: temperature of 1200-1250°C and time of 15-30 min.
[0014] Furthermore, in step (4), the temperature of the drying box is set to 70° C. and the time is 2 hours.
[0015] Furthermore, the iron ore powder is Bayan Obo iron ore concentrate.
[0016] Furthermore, the chemical composition of the Bayan Obo iron concentrate includes, by mass percentage, 67.20% TFe, 29.10% FeO, 0.72% CaO, 2.43% SiO2, 0.58% MgO, 0.50% Al2O3, 0.10% K2O, 0.13% Na2O, 0.31% F, and 0.75% S, and the iron ore particle size less than 0.074 mm accounts for 84%.
[0017] Furthermore, the chemical composition of the bentonite binder includes, by mass percentage, 2.50% CaO, 66.65% SiO2, 3.73% MgO, 14.52% Al2O3, 1.64% K2O, and 2.00% Na2O, and the proportion of bentonite particles less than 0.074 mm is 100%.
[0018] Furthermore, more than 20% of the pelletizing raw materials can be recycled, and the recycled mixed mineral powder is mixed more fully.
[0019] Furthermore, the drop strength of the pellets generated by the recycled mixed ore powder is greater than 5, the compressive strength of the raw balls is greater than 10N / piece, and the compressive strength of the finished balls is greater than 2500N / piece, meeting the quality indicators of qualified pellets.
[0020] Compared with the prior art, the beneficial technical effects of the present invention are:
[0021] The present invention can recycle more than 20% of the pelletizing raw materials by recycling the mixed ore powder abandoned in the laboratory pelletizing process, and the recycled mixed ore powder is more fully mixed. The pellets generated by the recycled mixed ore powder have a drop strength greater than 5, a raw ball compressive strength greater than 10N / piece, and a finished ball compressive strength greater than 2500N / piece, which meets the quality index of qualified pellets and realizes the process requirements of laboratory recycling of mixed ore powder for pelletizing. DETAILED DESCRIPTION
[0022] The technical solution of the present invention is described in detail below in conjunction with the embodiments.
[0023] In the embodiment of the present invention, a pellet preparation test was carried out using two raw materials, Bayan Obo iron concentrate and bentonite binder. The chemical composition of the Bayan Obo iron concentrate includes, by mass percentage, 67.20% TFe, 29.10% FeO, 0.72% CaO, 2.43% SiO2, 0.58% MgO, 0.50% Al2O3, 0.10% K2O, 0.13% Na2O, 0.31% F, and 0.75% S, and the iron concentrate particle size less than 0.074 mm accounts for 84%; the chemical composition of the bentonite binder includes, by mass percentage, 2.50% CaO, 66.65% SiO2, 3.73% MgO, 14.52% Al2O3, 1.64% K2O, and 2.00% Na2O, and the bentonite particle size less than 0.074 mm accounts for 100%; the chemical composition of the raw materials used in the pellet preparation test of each embodiment is shown in Table 1.
[0024] The chemical composition of the raw materials used in the oxidized pellet preparation test and the amount of raw materials used in each embodiment are shown in Table 1 and Table 2.
[0025] Table 1 Chemical composition and particle size composition of raw materials used in pellet preparation test in Example 1
[0026]
[0027] Table 2 Example pellet preparation test raw material usage / kg
[0028]
[0029] Example 1
[0030] Green balls with a particle size of 10-16 mm were prepared using the raw materials shown in Table 1 and the batching scheme shown in Table 2. The quality of the green balls produced and the quality of the recycled materials are shown in Table 3. The drop strength and compressive strength of the green balls made from the recycled mixed ore powder were tested; and the finished balls were roasted at 1200°C for 15 minutes, and the compressive strength and expansion rate of the finished balls were tested, as shown in Table 4. It can be seen that the present invention effectively recovers the mixed ore powder abandoned in the pelletizing test, and the finished balls produced can fully meet the requirements of blast furnace ironmaking production.
[0031] Example 2
[0032] Green balls with a particle size of 10-16 mm were prepared using the raw materials shown in Table 1 and the batching scheme shown in Table 2. The quality of the green balls produced and the quality of the recycled materials are shown in Table 3. The drop strength and compressive strength of the green balls made from the recycled mixed ore powder were tested; and the finished balls were roasted at 1200°C for 15 minutes, and the compressive strength and expansion rate of the finished balls were tested, as shown in Table 4. It can be seen that the present invention effectively recovers the mixed ore powder abandoned in the pelletizing test, and the finished balls produced can fully meet the requirements of blast furnace ironmaking production.
[0033] Example 3
[0034] Green balls with a particle size of 10-16 mm are prepared using the raw materials shown in Table 1 and the batching scheme shown in Table 2. The quality of qualified green balls and the quality of recycled materials are shown in Table 3. The drop strength and compressive strength of the green balls made from the recycled mixed ore powder are tested; and the finished balls are roasted at 1200°C for 15 minutes, and the compressive strength and expansion rate of the finished balls are tested, as shown in Table 4. It can be seen that the present invention effectively recovers the mixed ore powder abandoned by the laboratory production of pelletized ore, and the finished balls produced by the present invention can fully meet the requirements of blast furnace ironmaking production.
[0035] Table 3 Qualified pellet quality and recycled material quality of the examples / kg
[0036]
[0037] Table 4 Performance of pellets prepared from recycled materials in Example
[0038]
[0039] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.
Claims
1. A method for recovering mixed ore powder in the process of producing pellets in a laboratory, characterized in that: The steps include: (1) passing iron ore powder and bentonite binder through a 200-mesh sieve to control their particle size composition and mix them uniformly; (2) Spray water on the disc ball making machine to prepare 10-16 mm green balls, crush the excess mother balls and green balls with unqualified particle size, and remove the mixed mineral powder adhered to the disc and store it for recycling; (3) Weighing the green balls with qualified particle size; (4) Weighing the recovered mixed mineral powder and placing it in a drying box; Dry the moisture of the mineral powder while ensuring that it does not react; (5) Pass the dried mixed mineral powder through a 200-mesh sieve, take it out and make balls on a disc and spray water on it to produce green balls of 10-16 mm; (6) Testing the drop strength and compressive strength of the green balls in step (5); (7) drying, preheating, and roasting the green pellets prepared in step (5) to obtain finished oxidized pellets; The drying conditions of green balls include: temperature of 130-150℃, time of 40-60min; the preheating conditions include: temperature of 600-800℃, time of 10-15min; the roasting conditions include: temperature of 1200-1250℃, time of 15-30min.
2. The method for recovering mixed ore powder in the process of producing pellets in the laboratory according to claim 1, characterized in that: In the step (4), the temperature of the drying box is set to 70° C. and the drying time is 2 hours.
3. The method for recovering mixed ore powder in the process of producing pellets in the laboratory according to claim 1, characterized in that: The iron ore powder is Bayan Obo iron ore concentrate.
4. The method for recovering mixed ore powder in the process of producing pellets in the laboratory according to claim 1, characterized in that: The chemical composition of the Bayan Obo iron concentrate includes, by mass percentage, 67.20% TFe, 29.10% FeO, 0.72% CaO, 2.43% SiO2, 0.58% MgO, 0.50% Al2O3, 0.10% K2O, 0.13% Na2O, 0.31% F, and 0.75% S. The iron concentrate particle size is less than 0.074 mm, accounting for 84%.
5. The method for recovering mixed ore powder in the process of producing pellets in the laboratory according to claim 1, characterized in that: The chemical composition of the bentonite binder includes, by mass percentage, 2.50% CaO, 66.65% SiO2, 3.73% MgO, 14.52% Al2O3, 1.64% K2O, and 2.00% Na2O, and the proportion of bentonite particles less than 0.074 mm is 100%.
6. The method for recovering mixed ore powder in the process of producing pellets in the laboratory according to claim 1, characterized in that: More than 20% of the pelletizing raw materials can be recycled, and the recycled mixed mineral powder is mixed more fully.
7. The method for recovering mixed ore powder in the process of producing pellets in the laboratory according to claim 1, characterized in that: The drop strength of the pellets generated by the recycled mixed ore powder is greater than 5, the compressive strength of the raw balls is greater than 10N / piece, and the compressive strength of the finished balls is greater than 2500N / piece, meeting the quality indicators of qualified pellets.