Method for producing iron ore concentrates with different silicon contents through full magnetic beneficiation

Abstract

The invention belongs to the technical field of mineral separation of metal ore resources, and provides a method for producing iron ore concentrates with different silicon contents through full-magnetic mineral separation, which comprises the following steps of: obtaining grades corresponding to different silicon contents or silicon contents corresponding to different grades by utilizing a regression relational expression of iron ore concentrate TFe and SiO2; designing matching of operation modes of production ore feeding and elutriation equipment, calculating a theoretical value of field SiO2 control, comparing the theoretical value with a field test result, and selecting adjusting parameters corresponding to different ore feeding grades of the elutriation machine; after stirring, SiO2 fluctuation is finally provided for a user within the range of + / -0.2%, additional stacking by the user is not needed for production of different silicon contents, a mold can be rapidly replaced, stable and high-quality iron ore concentrate powder is provided for the user, and the sintering cost is reduced. And a solid foundation is laid for extremely exerting the enterprise efficiency, so that the comprehensive productivity, quality and cost of the enterprise are mutually coordinated, and the benefit maximization is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of metal ore resource beneficiation, and relates to a full magnetic beneficiation process, and a method for producing iron concentrates with different silicon contents through full magnetic beneficiation. Background Art

[0002] At present, the company's blast furnace sintering iron ore raw materials are composed of six different types of raw materials: Jianshan powder, Yuan powder, Eqiu, Yuanqiu, Sanshao and Sishao. Lanxian Mining organizes production according to the principle of the highest TFe recovery rate. Its SiO2 is carried out by ore dressing, basically between 4.5-4.8%. Lanxian Yuanjiacun Iron Mine is a fine-grained red magnetic mixed refractory iron ore. There are many types of iron minerals and gangue minerals. The iron minerals are embedded in fine particles. As the mining steps gradually decrease, the proportion of amphibole primary ore gradually increases. In order to ensure the TFe recovery rate and ensure the complete separation of minerals and gangue, the particle size of the second-stage cyclone -325 mesh has been increased from 90% to more than 92%. Continuing fine grinding will inevitably increase unnecessary energy consumption and grinding costs. Otherwise, the minerals and gangue are not completely separated, the TFe recovery rate decreases, and the absence of grinding or excessive grinding will lead to increased ore powder costs and negative benefits. It has been calculated that for every 0.1% decrease in SiO2 of Lan powder, the annual benefit loss is 22.69 million yuan, and for every 0.1% decrease in SiO2 of Jianshan powder, the annual benefit loss is 4.14 million yuan. In addition, the SiO2 stability rate of Lan powder is about 80%, which cannot meet the demand for sintering SiO2 greater than 85%.

[0003] In order to maximize the comprehensive economic benefits, the SiO2 of Jianshan powder is adjusted at any time according to the changes of Lan Mine. The stability rate of SiO2 of Jianshan powder is greater than 90%, which ultimately meets the control requirements of the median value and stability rate of SiO2 of sintered mixed ore.

[0004] Jianshan ore dressing process is a full magnetic process, three-stage grinding and classification + washing and separation process, such as Figure 1 As shown in the figure, the range of the panning machine to improve the concentrate grade is between 1.5-3%, and the design range of production silicon content is 6±0.5%. However, in actual production, according to the blast furnace ore matching requirements, the median SiO2 of the concentrate produced by Jianshan Iron Mine is between 5.3-7.0%, and the fluctuation range is ±0.2% of the tissue median. Moreover, it must arrive at the planned time node and cannot be piled separately. However, the domestic industry does not have such strict requirements on SiO2 in iron ore concentrate, nor does it have relevant control technology. Summary of the invention

[0005] The purpose of the present invention is to provide a method for producing iron concentrates with different silicon contents by full magnetic separation. Under the premise that the separation process remains unchanged, the production of iron concentrates with different silicon contents can be quickly switched, not only the quality of the iron concentrate is qualified and stable, but also the iron powders with different silicon contents do not need to be separately stacked during production, and direct transition can be achieved, thereby reducing blast furnace costs and maximizing the economic benefits before iron production.

[0006] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: A method for producing iron concentrates with different silicon contents by full magnetic separation comprises the following steps: S1. Determine the median of the final output iron ore concentrate SiO2; S2, regression analysis of the relationship between TFe and SiO2 in iron ore concentrate; S3, according to the determined median value of the SiO2 structure of the iron ore concentrate, the final concentrate TFe is obtained by using the regression relationship; S4. Determine the control range of the elutriator feeding TFe according to the final concentrate TFe and the lifting range of the elutriator; S5. According to the relationship between different silicon contents and the production time and number of elutriators, as well as the ball mill processing capacity, selection ratio, and organizational SiO2 theory, the best operation match of the elutriator is calculated. The operation modes of the elutriator include operation and direct flow. The direct flow means that the elutriator is not in operation and the slurry passes directly. S6. Calculate the control value of SiO2 of the theoretical on-site iron ore concentrate when running the elutriator; S7, according to the calculated theoretical on-site iron ore concentrate SiO2 control value, compare the on-site sampling results, and adjust the washing machine control parameters; S8. If the median silicon content before and after adjusting the washing machine control parameters does not exceed ±0.2%, direct transition can be achieved. If it exceeds ±0.2%, production scheduling should be planned in advance to adjust the median on-site organization, and the transition time should be stored and adjusted in the mixing tank.

[0007] Furthermore, S6 calculates the control value q1 of the theoretical on-site SiO2 of the iron ore concentrate when the elutriator is running, using the formula Qq=Q1.q1 +Q2.q2, where: Q represents the total processing capacity of the elutriator; q represents the median of the tissue of the final output iron concentrate SiO2; Q1 represents the processing capacity of the running elutriator; q1 represents the theoretical SiO2 of the running elutriator; Q2 represents the processing capacity of the direct elutriator; q2 represents the theoretical SiO2 of the direct elutriator; q2 is a fixed value, which is obtained based on the regression relationship between the iron ore TFe and SiO2.

[0008] Furthermore, the control parameters of the washing machine adjusted in S7 include the main water opening, the secondary water opening, the magnetic field strength, and the bottom valve opening.

[0009] Furthermore, the method for adjusting the control parameters of the elutriator in S7 includes: S71. When the on-site sampling result deviates from the theoretical on-site iron ore concentrate SiO2 control value by 0.3-1.5%, the main water opening and secondary water opening of the elutriator are adjusted first; S72, when the on-site sampling result deviates from the theoretical on-site iron ore concentrate SiO2 control value by 1.5-2.5%, the magnetic field strength and bottom valve opening of the elutriator are adjusted on the basis of the adjustment of the main water opening and the secondary water opening; S73. When the deviation between the on-site sampling results and the calculated theoretical on-site iron ore concentrate SiO2 control value is greater than 2.5%, it indicates that the properties of the ore have changed significantly and the ball mill's hourly processing capacity needs to be reduced.

[0010] The beneficial effect of the present invention is that the method of the present invention can quickly switch to produce iron ore concentrate powder with different silicon contents, and does not require users to stack them separately, providing users with stable and high-quality iron ore concentrate powder, reducing sintering costs. It lays a solid foundation for the ultimate performance of the enterprise, so that the comprehensive production capacity, quality and cost of the enterprise are coordinated with each other to achieve maximum benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the process flow chart of full magnetic ore dressing; Figure 2 This is the table of control parameters of elutriators with different silicon contents; Figure 3 This is a calculation table of the adjustment mode for different silicon contents, production hours, and number of equipment in operation. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with embodiments: A method for producing iron concentrates with different silicon contents by full magnetic separation comprises the following steps: S1. Determine the median of the final output iron ore concentrate SiO2; According to the required median value of SiO2 in iron ore concentrate and the test error, the median value of SiO2 in the final output iron ore concentrate is determined; S2. Regression analysis of the relationship between iron ore TFe and SiO2, based on one of the terms, the value of the other term can be known; S3, according to the determined median value of the SiO2 structure of the iron ore concentrate, the final concentrate TFe is obtained by using the regression relationship; S4. Determine the control range of TFe of the elutriator feed (approximately equal to four magnetic concentrates) according to the final concentrate TFe and the lifting range of the elutriator; S5. According to the relationship between different silicon contents and the production time and number of elutriators, as well as the ball mill processing capacity, selection ratio, and organizational SiO2 theory, the best operation match of the elutriator is calculated. The operation modes of the elutriator include operation and direct flow. The direct flow means that the elutriator is not in operation and the slurry passes directly. S6. Calculate the control value of SiO2 of the theoretical on-site iron ore concentrate when running the elutriator; Calculate the control value q1 of the theoretical on-site SiO2 of the running elutriator, using the formula Qq= Q1.q1 +Q2.q2, where: Q represents the total processing capacity of the elutriator; q represents the median of the final output of the iron concentrate SiO2; Q1 represents the processing capacity of the running elutriator; q1 represents the theoretical SiO2 of the running elutriator; Q2 represents the processing capacity of the straight-through elutriator; q2 represents the theoretical SiO2 of the straight-through elutriator; q2 is a fixed value, which is obtained based on the regression relationship between the iron concentrate TFe and SiO2;

[0013] S7. According to the calculated theoretical on-site iron ore SiO2 control value, compare the on-site sampling results and adjust the control parameters of the elutriator; the control parameters of the elutriator include the main water opening, the secondary water opening, the fixed magnetic field strength of the elutriator, the circulating magnetic field strength, the compensation magnetic field strength, the bottom valve opening, the bottom flow concentration, the overflow concentration, and the on-site overflow color. The control standards of the elutriator parameters with different silicon contents are as follows: Figure 2 As shown in Table 1.

[0014] Methods for adjusting the elutriator control parameters include: S71. When the on-site sampling result deviates from the theoretical on-site iron ore concentrate SiO2 control value by 0.3-1.5%, the main water opening and secondary water opening of the elutriator are adjusted first; S72, when the on-site sampling result deviates from the theoretical on-site iron ore concentrate SiO2 control value by 1.5-2.5%, the magnetic field strength and bottom valve opening of the elutriator are adjusted on the basis of the adjustment of the main water opening and the secondary water opening; S73. When the deviation between the on-site sampling results and the calculated theoretical on-site iron ore concentrate SiO2 control value is greater than 2.5%, it indicates that the properties of the ore have changed significantly and the ball mill's hourly processing capacity needs to be reduced.

[0015] S8. If the median silicon content before and after adjusting the washing machine control parameters does not exceed ±0.2%, direct transition can be achieved. If it exceeds ±0.2%, production scheduling should be planned in advance to adjust the median on-site organization, and the transition time should be stored and adjusted in the mixing tank. Example

[0016] Taking Jianshan Iron Ore dressing as an example, the full magnetic process is Figure 1 As shown, the washing equipment includes 6 sets of ∮2000mm washing machines, each with a processing capacity of 70t / h; 2 sets of ∮1200mm washing machines, each with a processing capacity of 50t / h. Take the example that the iron smelting plant requires Jianshan Iron Mine to produce iron concentrate with a SiO2 content of 6.2% as follows: The full magnetic separation process produces iron concentrate with a SiO2 content of 6.2%, including the following steps: S1. The test result of SiO2 in the iron smelting plant is about 0.2% lower than that of Jianshan Iron Mine. When the iron smelting plant requires production at 6.2%, the iron ore production is organized according to the SiO2 content of the iron ore concentrate at 6.4%; S2, the regression relationship between TFe and SiO2 of Jianshan Iron Mine iron concentrate is: TFe=71.992-0.7538SiO2 S3, when the SiO2 content of the washed iron concentrate is 6.4%, the corresponding TFe of the washed iron concentrate is 67.17%, and the appropriate increase in the grade of the wash machine concentrate is 1.5-3%, the feed grade of the wash machine (i.e. the grade of the four-magnetic concentrate) should be controlled at about 65%; S4, when the elutriator is in direct flow, the feed TFe is 65%, and the corresponding elutriator concentrate SiO2 is 9.3%; S5. Calculate the best operation match of the elutriator based on the relationship between different silicon contents and the production hours and number of elutriators, as well as the ball mill processing capacity, selection ratio, and organization SiO2 theory; S6. Calculate the theoretical value of on-site adjustment of the running elutriator based on the determined working hours, selection ratio (average value of the previous month), taste and median of on-site organization to ensure that it is within the design range of 6±0.5% of the elutriator. If it is not within the range, adjust the number of straight-through and running elutriators.

[0017] S7. According to the calculated theoretical on-site iron ore concentrate SiO2 control value, compare it with the on-site sampling results and adjust the washing machine control parameters; take samples and test the four-magnetic concentrate grade TFe, the running washing machine concentrate SiO2, and the final concentrate SiO2 once every hour.

[0018] 1. If the deviation between the on-site sampling result and the on-site adjustment theoretical value is within ±0.3%, and the final output of concentrate SiO2 is within the median requirement of ±0.2%, no adjustment is required on-site. Figure 3 The theoretical value for on-site adjustment in Table 2 is 5.78%. When the on-site sampling results are within the range of 5.78±0.3% and the final output concentrate SiO2 is within the range of 6.4±0.2%, no adjustment is required.

[0019] 2. If the on-site sampling result is 0.3-1.5% higher than the on-site adjustment theoretical value, and the final output concentrate SiO2 tends to be high, refer to the parameter control standards of the elutriator with different silicon contents in Table 1, and give priority to adjusting the main water opening and secondary water opening of the elutriator. Figure 3 The theoretical value for on-site adjustment in Table 2 is 5.78%. When the on-site sampling results are in the range of 6.08-7.28% and the final output concentrate SiO2 is increased from 6.4% to 6.4+0.5%, it is prioritized to increase the main and secondary water openings of the washing machine (the main water opening is adjusted from 40% to 48%, and the secondary water opening is adjusted from 18% to 23%).

[0020] 3. If the on-site sampling result is 0.3-1.5% lower than the on-site adjustment theoretical value, and the final output concentrate SiO2 shows a low trend, refer to the parameter control standards of the elutriator with different silicon contents and give priority to adjusting the main water opening and secondary water opening of the elutriator. Figure 3 The theoretical value for on-site adjustment in Table 2 is 5.78%. When the on-site sampling results are in the range of 4.28-5.48% and the final output concentrate SiO2 is reduced from 6.4% to 6.4-0.5%, it is prioritized to reduce the main and secondary water openings of the washing machine (the main water opening is adjusted from 48% to 40%, and the secondary water opening is adjusted from 23% to 18%).

[0021] 4. If the on-site sampling result is 1.5-2.5% higher than the on-site adjustment theoretical value, and the final output concentrate SiO2 exceeds the median value of 6.4+0.5%, adjust the magnetic field strength and bottom valve opening of the elutriator based on the adjustment of the primary and secondary water openings and the parameter control standards of the elutriator with different silicon contents. Figure 3 The theoretical value of on-site adjustment in Table 2 is 5.78%. When the on-site sampling results are in the range of 7.28-8.48% and the final output concentrate SiO2 exceeds 6.4+0.5%, based on the adjustment of the primary water opening and the secondary water opening, refer to Figure 2 Table 1 Parameter control standards of elutriation machines with different silicon contents. The field strength is adjusted from 16000 / 15000 / 14000 to 15000 / 14000 / 13000, and the bottom valve opening is adjusted from 18% to 13%.

[0022] 5. If the on-site sampling result is 1.5-2.5% lower than the on-site adjustment theoretical value, and the final output concentrate SiO2 is lower than the median value of 6.4-0.5%, on the basis of adjusting the primary water opening and the secondary water opening, refer to Figure 2 Table 1 Parameter control standards of elutriator with different silicon contents, adjusting the magnetic field strength and bottom valve opening of the elutriator. Figure 3 The on-site adjustment theoretical value in Table 2 is 5.78%. When the on-site sampling results are in the range of 4.28-3.28% and the final output concentrate SiO2 is lower than 6.4-0.5%, based on the adjustment of the main water opening and the secondary water opening, and referring to the parameter control standards of the washing machine with different silicon contents, the field strength is adjusted from 15000 / 14000 / 13000 to 16000 / 15000 / 14000, and the bottom valve opening is adjusted from 13% to 18%.

[0023] 6. If the on-site sampling result is higher than the on-site adjustment theoretical value by more than 2.5%, it means that the ore properties have changed significantly, and the feed grade of the panning machine is lower than the appropriate feed grade (65%), and the ball mill's processing capacity needs to be reduced. Figure 3The theoretical value of on-site adjustment in Table 2 is 5.78%. When the on-site sampling result exceeds 8.28% and the final output concentrate SiO2% exceeds 6.4+0.8%, the on-site measures of reducing the machine hours of each series are taken, and the machine hours are reduced by 10t each time. The machine hours of each series are reduced from 185t / h to 175t / h, 215t / h to 205t / h, and 100t / h to 90t / h. Observe the changes and conditions of the feed grade of the on-site washing machine, and the target feed grade of the washing machine reaches 65-66%.

[0024] 7. There are two mixing tanks, and the ore injection and ore discharge can be switched. When the final output of the concentrate SiO2 of the two mixing tanks reaches the median value of 6.4±0.2%, the time of each series is restored. After 2 hours, according to the ore grade of the washing machine, refer to Figure 2 Table 1 shows the control standards for the parameters of the elutriation machine with different silicon contents, and the parameters of the elutriation machine are adjusted.

[0025] The method of the present invention can quickly switch to produce iron ore concentrate powder with different silicon contents, and does not require users to stack them separately, providing users with stable and high-quality iron ore concentrate powder, reducing sintering costs. In the past five years, Jianshan has produced 15 kinds of iron ore concentrate powder with different silicon contents ranging from 5.3% to 7.0%, and has adjusted it for users 95 times in total. Users reported that the deviation between SiO2 and the median of the required structure was ±0.1%, and the daily indicator SiO2±0.2% stability rate reached more than 90%.

[0026] Moreover, through the collaborative development model of complementary advantages among mining companies, economic maximization is achieved. 2， This has laid a solid foundation for the company to maximize its efficiency. The company's comprehensive production capacity, quality and cost work together to maximize benefits.

Claims

1. A method for producing iron concentrates with different silicon contents by full magnetic separation, characterized in that: The steps include: S1. Determine the median of the final output iron ore concentrate SiO2; S2, regression analysis of the relationship between TFe and SiO2 in iron ore concentrate; S3, according to the determined median value of the SiO2 structure of the iron ore concentrate, the final concentrate TFe is obtained by using the regression relationship; S4. Determine the control range of the elutriator feeding TFe according to the final concentrate TFe and the lifting range of the elutriator; S5. According to the relationship between different silicon contents and the production time and number of elutriators, as well as the ball mill processing capacity, selection ratio, and organizational SiO2 theory, the best operation match of the elutriator is calculated. The operation modes of the elutriator include operation and direct flow. The direct flow means that the elutriator is not in operation and the slurry passes directly. S6. Calculate the control value of SiO2 of the theoretical on-site iron ore concentrate when running the elutriator; S7, according to the calculated theoretical on-site iron ore concentrate SiO2 control value, compare the on-site sampling results, and adjust the washing machine control parameters; S8. If the median silicon content before and after adjusting the washing machine control parameters does not exceed ±0.2%, direct transition can be achieved. If it exceeds ±0.2%, production scheduling should be planned in advance to adjust the median on-site organization, and the transition time should be stored and adjusted in the mixing tank.

2. The method for producing iron ore concentrates with different silicon contents by full magnetic separation according to claim 1, characterized in that: The control value q1 of the theoretical on-site iron ore SiO2 of the running elutriator is calculated in S6, and the formula Qq= Q1.q1 +Q2.q2 is adopted, wherein: Q represents the total processing capacity of the elutriator; q represents the median structure of the final output iron ore concentrate SiO2; Q1 represents the processing capacity of the running elutriator; q1 represents the theoretical SiO2 of the running elutriator; Q2 represents the processing capacity of the direct elutriator; q2 represents the theoretical SiO2 of the direct elutriator; q2 is a fixed value, which is obtained according to the regression relationship between the iron ore TFe and SiO2.

3. The method for producing iron ore concentrates with different silicon contents by full magnetic separation according to claim 1, characterized in that: The control parameters of the elutriator adjusted in S7 include the main water opening, the secondary water opening, the magnetic field strength, and the bottom valve opening.

4. The method for producing iron ore concentrates with different silicon contents by full magnetic separation according to claim 1, characterized in that: The method for adjusting the control parameters of the elutriator in S7 includes: S71. When the on-site sampling result deviates from the theoretical on-site iron ore concentrate SiO2 control value by 0.3-1.5%, the main water opening and secondary water opening of the elutriator are adjusted first; S72, when the on-site sampling result deviates from the theoretical on-site iron ore concentrate SiO2 control value by 1.5-2.5%, the magnetic field strength and bottom valve opening of the elutriator are adjusted on the basis of the adjustment of the main water opening and the secondary water opening; S73. When the deviation between the on-site sampling results and the calculated theoretical on-site iron ore concentrate SiO2 control value is greater than 2.5%, it indicates that the properties of the ore have changed significantly and the ball mill's hourly processing capacity needs to be reduced.

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