A method for stabilizing the output of a hematite reverse flotation system

Abstract

The present application belongs to the technical field of flotation process, and provides a method for stabilizing the output concentrate silica grade of hematite reverse flotation system, and proposes four methods for dealing with the situation when the mass percentage of silica in the output concentrate of the hematite reverse flotation system is in different intervals, mainly including: when the mass percentage of silica in the output concentrate of the system is in the qualified interval, adjusting the q 扫 interval based on the feeding conditions; when the mass percentage of silica in the output concentrate of the system is lower than the lower limit, adding concentrate to the flotation feed; when the mass percentage of silica in the output concentrate of the system is higher than the upper limit, using a multi-stage collector dosing method; and when the flotation process is extremely abnormal, temporarily storing the slurry in the agitation tank. By timely selecting different methods, various adverse factors in the hematite reverse flotation process can be overcome, the mass of the output concentrate can be stabilized in the qualified interval, and then stable qualified raw materials can be continuously provided for the ironmaking process.

Description

Technical Field

[0001] This invention belongs to the field of flotation technology and relates to the stabilization of the silica grade of the output concentrate. Specifically, it is a method for stabilizing the silica grade of the output concentrate from a hematite reverse flotation system. Background Technology

[0002] my country has abundant iron ore reserves, but their quality varies greatly, posing significant challenges to development and utilization. Among these, refractory hematite reserves account for one-third of the total reserves, with the Anshan-type magnetohematite ore, characterized by fine-grained dispersive ore, estimated at approximately 3 billion tons. Currently, anionic reverse flotation is widely used in hematite beneficiation plants. Considering the characteristics of Anshan-type sedimentary metamorphic magnetohematite, such as fine-grained iron mineral dispersive ore and diverse gangue minerals, combining anionic reverse flotation with weak and strong magnetic separation processes can achieve continuous and stable production, yielding qualified iron concentrate products.

[0003] Yuanjiacun Iron Mine is a typical fine-grained, complex, and difficult-to-process magnetic hematite mixed iron ore. The beneficiation process adopts a semi-autogenous grinding + ball milling - weak magnetic + strong magnetic - regrinding - anion reverse flotation process. Reverse flotation is the last and most important step in the beneficiation process, which directly determines the quality and yield of the output concentrate. It adopts a process of one roughing, one cleaning, and three scavenging, with the underflow of the first and second scavenging returned to the roughing and the underflow of the third scavenging returned to the first scavenging.

[0004] During mining operations, significant differences exist in the properties of various ore bodies, bands, and depths. As the TFe grade, particle size distribution, and gangue incorporation of the raw ore entering the mill change, the flotation feed conditions fluctuate accordingly. This fluctuation can lead to instability in concentrate quality, most directly manifested in the fluctuation of the silica mass percentage in the system's output iron concentrate. In the ironmaking process, the silica mass percentage primarily affects the acid-base balance of the blast furnace. High silica grades can increase the acidity of the furnace charge, necessitating the addition of alkaline substances such as calcium and magnesium to neutralize the acidity. According to the Dalian Commodity Exchange, in cost calculations, a one percentage point change in silica content impacts ironmaking costs by approximately RMB 15 per ton. Therefore, continuous adjustments to the flotation process are necessary in daily production to stabilize the silica mass percentage in the system's output iron concentrate, ensuring a consistent supply of qualified raw materials for the ironmaking process.

[0005] Conventional flotation process adjustments are results-oriented, passively adjusting based on concentrate index test results. The direction and extent of these adjustments rely heavily on experience and observation, making them highly subjective and prone to over-adjustment or errors. Furthermore, the average testing process for concentrate indexes takes approximately two hours, and the effects of flotation process adjustments also take about two hours to materialize in the concentrate indexes. These factors—delayed testing, non-standardized process adjustments, and long adjustment cycles—can easily lead to continuous exceedances of the silica percentage in the iron concentrate output from the flotation system, thus causing significant negative impacts on the ironmaking process.

[0006] Given the above, there is a need in the art for a stable and efficient reverse flotation control method that can eliminate or at least alleviate all or part of the defects in the prior art. Summary of the Invention

[0007] The purpose of this invention is to provide a method for stabilizing the silica mass percentage in the output concentrate of a hematite reverse flotation system. This method aims to eliminate the negative impact of unfavorable factors such as variable feeding conditions, delayed test indicators, non-standardized process adjustments, and long process adjustment cycles on the stability of the silica mass percentage in the output iron concentrate during the adjustment of the hematite reverse flotation process, thereby providing qualified raw materials for the ironmaking process.

[0008] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0009] A method for stabilizing the silica grade of the concentrate output from a hematite reverse flotation system includes the following:

[0010] S1. When the silica grade of the concentrate output from the hematite reverse flotation system is within the acceptable quality range, the feed flow rate q of the scavenging pump tank, i.e., the feed flow rate of the scavenging flotation machine, is adjusted based on the feeding conditions. 扫 The range has been adjusted.

[0011] S2. When the silica grade of the concentrate output from the hematite reverse flotation system is lower than the lower limit, concentrate is added to the flotation feed.

[0012] S3. When the silica grade of the concentrate output from the hematite reverse flotation system is higher than the upper limit, the collector is added in multiple stages.

[0013] S4. When the hematite reverse flotation process is extremely abnormal, the unqualified slurry is temporarily stored in the newly added stirring tank of the flotation system to buy time for the flotation process to be adjusted and restored.

[0014] In S1, q is based on the feeding conditions. 扫 The method for adjusting intervals includes the following steps:

[0015] S11. Install flow meters on the flotation feed pipeline and the scavenging feed pipeline to detect the slurry flow rate data in real time, and install a slurry concentration meter on the flotation feed pipeline to detect the slurry mass concentration data in real time.

[0016] S12. Calculate the amount of dry ore entering the system per unit time (m) using the formula. 矿石 ;

[0017] S13, Set q 扫 In a ratio of the amount of dry ore entering the flotation m 矿石 The relevant reasonable range, namely:

[0018] q 扫 The upper limit of the control is 1.1*m 矿石 *K;

[0019] q 扫 The control median value is m 矿石 *K;

[0020] q 扫 The lower control limit is 0.9*m 矿石 *K;

[0021] The K value increases slightly with increasing flotation temperature, ranging from 1.4 to 1.6.

[0022] S14. When the percentage of silica in the hematite reverse flotation system output concentrate is around the median, q 扫 Adjustments:

[0023] Let P be the median value for the mass percentage control of silica concentrate, and let the quality acceptable range be [Pa, P+a]. The values ​​of P and a within the quality acceptable range vary with demand.

[0024] When the system output concentrate silica mass percentage is in the range [P, P+a], or when the system output concentrate silica mass percentage is greater than P+a, the liquid level of the roughing and cleaning flotation machines is increased by 0.02*m. 矿石 *K increases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. Repeat the above steps if necessary to bring the mass percentage of silica in the concentrate closer to the median value P, until q 扫 Reaching q 扫 The upper limit of control;

[0025] When the system output concentrate silica mass percentage is in the range [Pa, P], or when the system output concentrate silica mass percentage is less than Pa, the liquid level of the roughing and cleaning flotation machines is reduced by 0.02*m. 矿石 *K decreases by q 扫Then observe the mass percentage of silica in the concentrate after two hours. Repeat the above steps if necessary to bring the mass percentage of silica in the concentrate closer to the median value P, until q 扫 Reaching q 扫 The lower limit of control.

[0026] S15, Amount of dry ore fed into the flotation tank (m) 矿石 When q changes 扫 Adjustments:

[0027] When m 矿石 When q increases, 扫 Also increase the corresponding Δm 矿石 *K;

[0028] When m 矿石 When q decreases, 扫 Also reduces the corresponding Δm 矿石 *K;

[0029] Where Δm 矿石 The amount of dry ore fed into the flotation is m 矿石 The change value.

[0030] S16. When the grade of the ore entering the flotation changes, q 扫 Adjustments:

[0031] When the grade of the ore entering the flotation increases by 1%, q 扫 Reduce by 0.02*m 矿石 *K;

[0032] When the grade of the ore entering the flotation decreases by 1%, q 扫 Increase by 0.02*m 矿石 *K.

[0033] The method for feeding the flotation feed into the concentrate in S2 includes:

[0034] S21. Install a silica distribution pipe at the flotation feed box to connect to the concentrate collection box. Install regulating valves and flow meters on the pipe to regulate the slurry flow. The flotation feed box is located at a high position. Through the silica distribution pipe, the flotation feed slurry can flow from the feed box into the concentrate collection box by gravity and mix with the concentrate.

[0035] S22. Calculate the flow rate V_feed of the flotation slurry added to the concentrate;

[0036] S23. By operating the regulating valve in conjunction with the flow meter, the calculated slurry flow rate V is fed into the system. The latest slurry flow rate V is calculated every hour based on the latest data obtained from laboratory tests, and adjustments are made on-site to ensure that the final output silica mass percentage of the system concentrate is stabilized within the qualified quality range.

[0037] The method for multi-stage addition of the collector in S3 is as follows: A new reagent addition point is added to the roughing process; when the mass percentage of silica in the system output concentrate is greater than P+a, q... 扫 When the interval adjustment method is insufficient to adjust the percentage of silica in the system output concentrate to the qualified level in a short period of time, a new reagent point is added to the roughing process. With the total amount of collector remaining unchanged, the reagent system is adjusted to a ratio of 7:1:1 for the reagent addition points of the roughing process, the newly added reagent points of the roughing process, and the reagent addition points of the fine process.

[0038] The method for temporarily storing the slurry in the stirred tank in S4 is as follows:

[0039] S41. A new concentrate storage and mixing tank is built in the flotation system and connected to the concentrate mixing tank. It is equipped with a circulation pump. The concentrate mixing tank and the concentrate storage and mixing tank can transfer slurry to each other. The concentrate storage and mixing tank can store more than 3 hours' worth of slurry output from the hematite reverse flotation system.

[0040] S42. When the flotation process is extremely abnormal, and the percentage of silica in the output concentrate deviates too much from the qualified range, and it is expected that adjustments such as q-scan range adjustment, adding concentrate to the flotation feed, and multi-stage addition of collectors will not be able to adjust it to the qualified range in time, the concentrate temporary storage mixing tank will be started. The concentrate mixing tank will stop sending slurry to the filtration workshop, and the unqualified slurry will be transported to the concentrate temporary storage mixing tank for temporary storage through a circulating pump to buy time for process adjustment. When the flotation process returns to normal, the unqualified slurry will be pumped into the concentrate mixing tank at a small flow rate through the circulating pump to mix with the qualified slurry and then transported to the filtration workshop.

[0041] The beneficial effects of this invention are: by using four methods to deal with different ranges of silica mass percentage in the output concentrate of the flotation system, it solves the problems faced in the previous flotation process adjustment process, such as variable feed conditions, delayed test results of process indicators, non-standard operation, and excessively long process adjustment cycle. This makes the silica mass percentage in the output concentrate of the flotation system stable, and thus can continuously provide iron concentrate products with stable and qualified silicon indicators for the next ironmaking process. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the flotation system of the present invention;

[0043] In the diagram: 1. Flow meter one; 2. Flow meter two; 3. Slurry concentration meter; 4. Silicon distribution pipeline; 5. Control valve; 6. Flow meter three. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0045] A method for stabilizing the silica grade of the concentrate output from a hematite reverse flotation system includes:

[0046] Let P be the median value for the controlled percentage of silica in the concentrate, and let [Pa, P+a] be the acceptable quality range. When the percentage of silica in the concentrate falls within the acceptable range, the product quality is stable and under control. Values ​​above or below the acceptable range are considered unacceptable. This indicates that the silica percentage output from the hematite reverse flotation system is unstable and not under control; the values ​​of P and a within the acceptable quality range vary with demand. Let q be the feed flow rate to the scavenging pump tank, i.e., the feed flow rate to the scavenging flotation machine. 扫 ;

[0047] S1, when the silica mass percentage of the hematite reverse flotation system output concentrate is within the acceptable quality range, based on the feed conditions q 扫 Range adjustment method:

[0048] S11, such as Figure 1 As shown, flow meter 1 is installed on the flotation feed pipeline, flow meter 2 is installed on the scavenging feed pipeline to detect the slurry flow rate data in real time, and slurry concentration meter 3 is installed on the flotation feed pipeline to detect the mass concentration data of the flotation slurry in real time.

[0049] S12. Calculate the amount of dry ore fed into the hematite reverse flotation system according to the formula;

[0050] C = ρ 矿石 (ρ 矿浆 -ρ 水 ) / ρ 矿浆 (ρ 矿石 -ρ 水 (1)

[0051] ρ 矿浆 =m 矿浆 / v 矿浆 (2)

[0052] C = m 矿石 / m 矿浆 (3)

[0053] Solving equations (1), (2), and (3) simultaneously yields the formula for calculating the amount of dry ore to be floated:

[0054] m 矿石 =Cv 矿浆 ρ 矿石 / ρ 矿石 (1-C)+C(4)

[0055] Where: m 矿石 This refers to the amount of dry ore added to the float;

[0056] m 矿浆 For the quality of the slurry fed into the flotation process;

[0057] C represents the mass concentration of the feed slurry;

[0058] v 矿浆 This refers to the volume of the slurry fed into the flotation tank.

[0059] ρ 矿石 The density of the ore being floated;

[0060] ρ 矿浆 The density of the slurry being floated;

[0061] ρ 水 This is the density of water.

[0062] The mass concentration C of the flotation slurry and the hourly flotation slurry flow rate V detected by the flow meter are used to determine the flotation slurry mass concentration C and the hourly flotation slurry flow rate V. 矿浆 The known density ρ of the ore to be floated 矿石 Substituting into formula (4), the hourly feed dry ore volume of the hematite reverse flotation system is obtained;

[0063] S13. Let the ore flow rate in the scavenging pump tank, i.e. the ore feed flow rate of the scavenging flotation machine, be q. 扫 Its main component is the overflow foam from the roughing flotation machine, directly representing the amount of overflow foam in the roughing process and indirectly representing the amount of overflow foam in the cleaning process. 扫 The grade of the concentrate output from the hematite reverse flotation system is highly correlated with the concentration; as the grade increases, the percentage of silica in the iron concentrate output by the system also increases. Therefore, q... 扫 As the main control indicator for adjusting the flotation process, it should be controlled within a reasonable range related to the amount of dry ore fed into the flotation system to balance the adjustment of the silica content output from the hematite reverse flotation system and the stability and health of the flotation process: q 扫 The upper limit of the control is 1.1*m 矿石 *K;

[0064] q 扫 The control median value is m 矿石 *K;

[0065] q 扫 The lower control limit is 0.9*m 矿石 *K;

[0066] Among them, the K value increases slightly with the increase of flotation temperature, and the value ranges from 1.4 to 1.6; when q 扫 When the flow rate is below the lower limit, the middlings circulation rate in the flotation process is too low, and the system becomes vulnerable; when q 扫 When the flow rate exceeds the upper limit, the middlings circulation rate in the flotation process becomes too high, leading to a deterioration in the system's separation efficiency. Therefore, daily process adjustments are based on the changing trend of the silica mass percentage in the system's output concentrate, using q as the reference value. 扫 The main control method is range control.

[0067] The specific method for adjusting the q-scan interval is as follows:

[0068] S14. Adjustment method for the silica mass percentage of the hematite reverse flotation system output concentrate around the median value:

[0069] When the system outputs a concentrate silica mass percentage within the range [P, P+a], the liquid level in the roughing and cleaning flotation machines is increased by 0.02*m. 矿石 *K increases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. If necessary, repeat the above steps to bring the mass percentage of silica in the concentrate closer to the median value P, until q 扫 This operation can also be performed when the system outputs a concentration of silica greater than P+a.

[0070] When the system outputs a concentrate silica mass percentage within the range of [Pa, P], the liquid level in the roughing and cleaning flotation machines is reduced by 0.02*m. 矿石 *K decreases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. If necessary, repeat the above steps to bring the mass percentage of silica in the concentrate closer to the median value P, until q 扫 This operation can also be performed when the mass percentage of silica in the concentrate output by the system is less than Pa.

[0071] Through the above two operations, the system outputs a concentration of silica mass percentage that fluctuates around the median value P, always remaining within the acceptable quality range.

[0072] S15, Amount of dry ore fed into the flotation tank (m) 矿石 Adjustment methods when changes occur:

[0073] When m 矿石 When increasing or decreasing, q 扫 It is also necessary to increase or decrease the corresponding Δm. 矿石 *K, to stabilize product quality.

[0074] S16. Adjustment method when the grade of the feed ore changes:

[0075] When the grade of the ore entering the flotation increases or decreases by 1%, q 扫 It is also necessary to reduce or increase by 0.02*m 矿石 *K, to stabilize product quality.

[0076] S2. When the silica mass percentage of the system output concentrate is less than Pa due to sudden changes in the selectivity of the feed ore, the product quality is unqualified. In this case, the interval adjustment method of q-sweep is difficult to adjust the silica mass percentage of the system output concentrate to the qualified level in a short time. Therefore, it is necessary to supplement the operation of adding concentrate to the flotation feed slurry to quickly raise the silica mass percentage of the concentrate to the qualified range.

[0077] When the silica mass percentage of the system output concentrate is lower than the lower limit, the flotation feed method includes the following steps:

[0078] S21, such as Figure 1 As shown, a silica distribution pipe 4 is installed at the flotation feed box to connect to the concentrate collection box. A regulating valve 5 and a flow meter 6 are installed on the silica distribution pipe 4 to regulate the slurry flow. Due to the gravity flow arrangement of the flotation process, the feed box is generally located at a high position. Through the silica distribution pipe, the flotation feed slurry can flow from the feed box to the concentrate collection box and mix with the concentrate.

[0079] S22. Calculate the flow rate V of the concentrate feed slurry. 给矿

[0080] The volume of the flotation slurry to be fed with concentrate can be calculated using the following formula:

[0081]

[0082]

[0083]

[0084]

[0085] Solving equations (5), (6), (7), and (8) simultaneously yields the formula for calculating the flow rate of the flotation slurry added to the concentrate:

[0086]

[0087] Where: m 给矿 —Add dry feed ore;

[0088] m 给矿浆 —The quality of the feed slurry;

[0089] m 精矿 —Dry weight of concentrate;

[0090] A1—Silica grade of the flotation feed ore;

[0091] A2—Mass percentage of silica in concentrate;

[0092] A3—Percentage of silica mass in the output concentrate after silicon preparation;

[0093] C—Pulp mass concentration;

[0094] v 矿浆 —Volume of feed slurry added;

[0095] ρ 矿石 —Ore density;

[0096] ρ 水 —Water density.

[0097] The flotation slurry concentration C measured by the flotation slurry concentration meter, the silica grade data A1 and A2 obtained from laboratory analysis, and the known flotation ore density data ρ are used. 矿石 Substituting the expected system output silica grade A3 after adding the feed slurry into formula (9), the required feed slurry flow rate v can be obtained. 给矿 .

[0098] S23. At the production site, the calculated slurry flow rate V is input by operating the regulating valve in conjunction with the flow meter. 给矿 The latest slurry flow rate V is calculated based on the latest data obtained from hourly laboratory tests. 给矿 Adjustments were made on-site to ensure that the final output of the system, the percentage of silica in the concentrate, remained within the acceptable range.

[0099] S3. Multi-stage dosing method for collectors when the system output concentrate silica mass percentage is higher than the upper limit:

[0100] Currently, the conventional collector dosing setting for reverse flotation of hematite is to do roughing reagents in the slurry mixing tank before flotation and do fine cleaning reagents before the fine cleaning flotation machine, with a roughing to fine cleaning reagent ratio of 8:1.

[0101] Add a reagent dosing point before the third-to-last flotation machine in the roughing stage. When the percentage of silica in the system output concentrate exceeds P+a due to sudden changes in the washability of the feed ore, excessively low flotation temperature, or abnormalities in the beneficiation water system, q... 扫 The interval adjustment method is difficult to adjust the percentage of silica in the output concentrate of the system to the qualified level in a short period of time. At this time, start the reagent addition point of the third to last flotation machine in the roughing stage. Under the condition that the total amount of collector remains unchanged, adjust the reagent system of 8:1 ratio of roughing and cleaning collector addition to 7:1:1 ratio of roughing, roughing 5# and cleaning collector addition.

[0102] Shifting from two-stage to three-stage dosing can quickly and effectively increase the grade of the system's output concentrate, thereby reducing the percentage of silica in the output concentrate to within the acceptable range. However, while this method reduces the grade of the system's output silica, it also significantly increases the grade of the system's tailings and significantly reduces the metal recovery rate. Therefore, three-stage dosing should only be initiated to adjust the process when the percentage of silica in the system's output concentrate is significantly higher than the acceptable range.

[0103] S4. Method for temporarily storing slurry in a stirred tank when the flotation process is extremely abnormal.

[0104] The flotation system has a concentrate mixing tank for temporary storage and mixing of concentrate slurry. The bottom of the concentrate mixing tank is connected to a concentrate pump to transport the concentrate to the filtration workshop. There is also a tailings mixing tank for temporary storage and mixing of tailings slurry. The bottom of the tailings mixing tank is connected to a diaphragm pump to transport the tailings to the tailings dam.

[0105] A new concentrate storage mixing tank is built in the flotation system and connected to the concentrate mixing tank. It is equipped with a circulation pump. The concentrate mixing tank and the concentrate storage mixing tank can transfer slurry to each other. The concentrate storage mixing tank can store more than 3 hours' worth of slurry output from the hematite reverse flotation system.

[0106] When the flotation process is extremely abnormal, the system output concentrate silica mass percentage deviates too much from the acceptable range and the expected pass rate is q. 扫 If adjustments to the flotation process, including the addition of concentrate to the flotation feed and multi-stage addition of collectors, fail to achieve timely and satisfactory results, the concentrate temporary storage mixing tank is activated. The concentrate mixing tank stops supplying slurry to the filtration workshop, and the substandard slurry is temporarily stored in the concentrate temporary storage mixing tank via a circulating pump to buy time for process adjustments. Once the flotation process returns to normal, the substandard slurry is pumped into the concentrate mixing tank at a low flow rate via a circulating pump to mix with the qualified slurry before being transported to the filtration workshop to maintain a stable and qualified quality of the system's output concentrate product.

[0107] Example

[0108] Currently, Taiyuan Iron & Steel Group requires a median silica content (P) of 4.4% for the concentrate powder shipped by Lanxian Mining Company. The acceptable quality range is [4.2, 4.6]. When the silica content falls within this range, the product quality is stable and under control. Contents above or below this range are considered unacceptable, indicating that the quality of the system's output concentrate is not stably under control. The following is a method for adjusting the silica content of the stable system output concentrate:

[0109] 1. When the system outputs the percentage of silica in the concentrate within the acceptable range, q is based on the feeding conditions. 扫 Range adjustment method:

[0110] 1. Install flow meters on the flotation feed pipeline and scavenging feed pipeline in the flotation plant to monitor the slurry flow rate in real time, and install a slurry concentration meter on the flotation feed pipeline to monitor the slurry concentration in real time.

[0111] 2. Derive the formula for calculating the amount of dry ore fed into the system.

[0112] 3. Combine the concentration data C of the feed slurry detected by the concentration meter and the hourly feed slurry flow rate V detected by the flow meter. 矿浆 Known density data of the ore being floated, ρ 矿石 Substituting into the above formula, we can obtain the hourly dry ore feed rate M of the system. 矿石 .

[0113] 4. The ore flow rate in the scavenging pump pool is q. 扫 , q 扫 As the main control indicator for adjusting the flotation process, it is controlled within a range similar to m. 矿石 The relevant reasonable range is to balance the adjustment of the silica content in the system output and the stability and health of the flotation process:

[0114] q 扫 Control limit: 1.1*m 矿石 *K

[0115] q 扫 Control median: m 矿石 *K

[0116] q 扫 Lower control limit: 0.9*m 矿石 *K

[0117] For the flotation process of Yuanjiacun Iron Mine, the value of K is between 1.4 and 1.6, with a higher value when the flotation pulp temperature is high and a lower value when the flotation pulp temperature is low.

[0118] 5. Specific q 扫 The interval adjustment method is as follows:

[0119] ① The system output concentrate silica mass percentage is adjusted around the median value. When the system output concentrate silica mass percentage is in the range of [4.4, 4.6], the level of the roughing and cleaning flotation machines is increased by 0.02*m. 矿石 *K increases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. If necessary, repeat the above operation to bring the mass percentage of silica in the concentrate closer to the median value of 4.4%, until q 扫 This operation can also be performed when the system output concentrate silica mass percentage is greater than 4.6%; when the system output concentrate silica mass percentage is in the range of [4.2, 4.4], the liquid level of the roughing and cleaning flotation machines is reduced by 0.02*m. 矿石 *K decreases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. If necessary, repeat the above operation to bring the mass percentage of silica in the concentrate closer to the median value of 4.4%, until q 扫 This operation can also be performed when the system outputs a concentrate silica mass percentage of less than 4.2%.

[0120] Through the above two operations, the system output concentrate silica mass percentage fluctuates around the median value of 4.4%, always remaining within the qualified range.

[0121] ② Adjustments when the amount of dry ore fed into the flotation changes. When m 矿石 When increasing or decreasing, q 扫 It is also necessary to increase or decrease the corresponding Δm. 矿石 *K, to stabilize product quality.

[0122] ③ Adjustments when the flotation grade changes. The flotation grade of Lanxian Mining Company fluctuates between 39% and 44%. For every 1% increase or decrease in the flotation ore grade, q... 扫 It is also necessary to reduce or increase by 0.02*m 矿石 *K, to stabilize product quality.

[0123] II. Flotation feed method when the silica mass percentage in the system output concentrate is below the lower limit:

[0124] 1. The flotation workshop of Lanxian Mining Company has three parallel flotation series. A silica distribution pipeline is installed at the feed box of the second series flotation to connect to the concentrate collection box. Regulating valves and flow meters are installed on the pipeline to regulate the slurry flow. Since the feed box is located at a high position, the flotation slurry can flow by gravity from the feed box into the concentrate collection box at a lower position through the silica distribution pipeline to mix with the concentrates of the three series, thereby adjusting the final silica mass percentage of the concentrate.

[0125] 2. When the percentage of silica in the system output concentrate is less than 4.2% due to sudden changes in the selectivity of the feed ore, the product quality is considered substandard. In this case, q 扫 The interval adjustment method is difficult to adjust the silica mass percentage of the system output concentrate to the qualified range in a short time. Therefore, it is necessary to supplement the operation of adding concentrate to the flotation slurry to quickly raise the silica mass percentage of the concentrate to the qualified range.

[0126] 3. Derive the formula for calculating the volume of the flotation slurry added to the concentrate.

[0127] 4. Combine the concentration data C of the feed slurry measured by the concentration meter, the silica grade data A1 and A2 obtained from laboratory analysis, and the known density data ρ of the feed ore. 矿石 Substituting the expected percentage of silica in the concentrate output after silicon addition (A3) into the calculation formula, the required flotation slurry flow rate (v) can be obtained. 给矿 At present, Lanxian Mining Company uses A3 at 4.4%. The production site uses valves and flow meters to adjust the calculated slurry flow rate. Every hour, the latest slurry flow rate is calculated based on the latest grade and concentration data. The operation is carried out on site to stabilize the final output silica grade of the system within the qualified range. When the A2 value returns to or exceeds the qualified range, the operation of adding concentrate to the flotation slurry is stopped on site.

[0128] III. Multi-stage dosing method for collectors when the percentage of silica in the system output concentrate exceeds the upper limit:

[0129] 1. The collector dosing setting for the hematite reverse flotation process of Lanxian Mining Company is as follows: roughing dosing is carried out in the slurry mixing tank before flotation, and cleaning dosing is carried out before the cleaning flotation machine. The ratio of roughing to cleaning dosing is 8:1.

[0130] 2. Add a collector dosing point before the third-to-last flotation machine in the roughing stage. If the silica content in the output concentrate exceeds 4.6% due to sudden changes in the washability of the feed ore, excessively low flotation temperature, or abnormalities in the beneficiation water system, the product quality will be substandard. At this point, q... 扫 The interval adjustment method is difficult to adjust the percentage of silica in the output concentrate of the system to the qualified level in a short period of time. At this time, start the reagent addition point of the third to last flotation machine in the roughing stage. With the total amount of collector unchanged, adjust the reagent system of 8:1 ratio of roughing and cleaning collector to 7:1:1 ratio of roughing, roughing 5#, and cleaning collector.

[0131] 3. When the percentage of silica in the concentrate output by the system is significantly higher than the acceptable range, initiate three dosing cycles to adjust the process. When the percentage of silica in the concentrate output by the system returns to or falls below the acceptable range, promptly close the three dosing points and restore the original dosing parameters.

[0132] IV. Method for temporarily storing slurry in a stirred tank when the flotation process is extremely abnormal.

[0133] 1. The flotation system of Lanxian Mining Company has one concentrate mixing tank, which is used to temporarily store and mix concentrate slurry. The bottom of the mixing tank is connected to a concentrate pump to transport the concentrate to the filtration workshop. There is also one tailings mixing tank, which is used to temporarily store and mix tailings slurry. The bottom of the mixing tank is connected to a diaphragm pump to transport the tailings to the tailings dam.

[0134] 2. Concentrate temporary storage and mixing tank is constructed. The concentrate temporary storage and mixing tank is connected to the concentrate mixing tank and equipped with a circulation pump, which can transfer slurry between them. The concentrate temporary storage and mixing tank can store more than 3 hours' worth of slurry output from the flotation system.

[0135] 3. When the flotation process is extremely abnormal, and the percentage of silica in the system output concentrate deviates significantly from the acceptable range (e.g., exceeding 5%), and it is anticipated that the first three methods will not be able to adjust it to acceptable levels in time, the concentrate temporary storage mixing tank will be activated. The tank will stop supplying slurry to the filtration workshop, and the substandard slurry will be temporarily stored in the concentrate temporary storage mixing tank via a circulating pump, buying time for process adjustment. Once the flotation process returns to normal, at an appropriate time, the abnormal slurry will be pumped in at a small flow rate into the concentrate mixing tank to mix with the acceptable slurry before being supplied to the filtration workshop, thus maintaining the stable and acceptable quality of the system output concentrate product.

Claims

1. A method for stabilizing the silica grade of the concentrate output from a hematite reverse flotation system, characterized in that: Includes the following: S1. When the silica grade of the concentrate output from the hematite reverse flotation system is within the acceptable quality range, the feed flow rate q of the scavenging pump tank, i.e., the feed flow rate of the scavenging flotation machine, is adjusted based on the feeding conditions. 扫 Adjusting the interval involves the following steps: S11. Install flow meters on the flotation feed pipeline and the scavenging feed pipeline to detect the slurry flow rate data in real time, and install a slurry concentration meter on the flotation feed pipeline to detect the slurry mass concentration data in real time. S12. Calculate the amount of dry ore entering the system per unit time (m) using the following formula. 矿石 ; m 矿石 =Cv 矿浆 r 矿石 / (p 矿石 (1-C)+C); Where: m 矿石 V represents the amount of dry ore fed into the flotation system; C represents the mass concentration of the ore pulp fed into the flotation system; v 矿浆 ρ is the volume of the slurry fed into the flotation tank. 矿石 The density of the ore being floated; S13, Set q 扫 In a ratio of the amount of dry ore entering the flotation m 矿石 The relevant reasonable range, namely: q 扫 The upper limit of the control is 1.1*m 矿石 *K; q 扫 The control median value is m 矿石 *K; q 扫 The lower control limit is 0.9*m 矿石 *K; The K value increases slightly with increasing flotation temperature, ranging from 1.4 to 1.

6. S14. When the percentage of silica in the hematite reverse flotation system output concentrate is around the median, q 扫 Adjustments: Let P be the median value for the percentage of silica content in the concentrate, and let the quality acceptable range be [Pa, P+a]. The values ​​of P and a in the quality acceptable range vary with demand. When the system output concentrate silica mass percentage is in the range [P, P+a], or when the system output concentrate silica mass percentage is greater than P+a, the liquid level of the roughing and cleaning flotation machines is increased by 0.02*m. 矿石 *K increases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. Repeat the above steps if necessary to bring the mass percentage of silica in the concentrate closer to the median value P, until q 扫 Reaching q 扫 The upper limit of control; When the system output concentrate silica mass percentage is in the range [Pa, P], or when the system output concentrate silica mass percentage is less than Pa, the liquid level of the roughing and cleaning flotation machines is reduced by 0.02*m. 矿石 *K decreases by q 扫 Then observe the mass percentage of silica in the concentrate after two hours. Repeat the above steps if necessary to bring the mass percentage of silica in the concentrate closer to the median value P, until q 扫 Reaching q 扫 The lower limit of control; S15, Amount of dry ore fed into the flotation tank (m) 矿石 When q changes 扫 Adjustments: When m 矿石 When q increases, 扫 Also increase the corresponding ∆m 矿石 *K; When m 矿石 When q decreases, 扫 Also reduces the corresponding ∆m 矿石 *K; Where ∆m 矿石 The amount of dry ore fed into the flotation is m 矿石 The change value; S16. When the grade of the ore entering the flotation changes, q 扫 Adjustments: When the grade of the ore entering the flotation increases by 1%, q 扫 Reduce by 0.02*m 矿石 *K; When the grade of the ore entering the flotation decreases by 1%, q 扫 Increase by 0.02*m 矿石 *K; S2. When the silica grade of the concentrate output from the hematite reverse flotation system is lower than the lower limit, concentrate is added to the flotation feed. S3. When the silica grade of the concentrate output from the hematite reverse flotation system is higher than the upper limit, the collector is added in multiple stages. S4. When the hematite reverse flotation process is extremely abnormal, the unqualified slurry is temporarily stored in the newly added stirring tank of the flotation system to buy time for the flotation process to be adjusted and restored.

2. The method for stabilizing the silica grade of the concentrate output from a hematite reverse flotation system according to claim 1, characterized in that: The method for feeding the flotation feed into the concentrate in S2 includes: S21. Install a silica distribution pipe at the flotation feed box to connect to the concentrate collection box. Install regulating valves and flow meters on the pipe to regulate the slurry flow. The flotation feed box is located at a high position. Through the silica distribution pipe, the flotation feed slurry can flow from the feed box into the concentrate collection box by gravity and mix with the concentrate. S22. Calculate the flow rate V of the concentrate feed slurry. 给矿 ; S23. By operating the regulating valve in conjunction with the flow meter, input the calculated slurry flow rate V. 给矿 The latest slurry flow rate V is calculated based on the latest data obtained from hourly laboratory tests. 给矿 Adjustments were made on-site to ensure that the final output of the system, the percentage of silica in the concentrate, remained within the acceptable range.

3. The method for stabilizing the silica grade of the concentrate output from a hematite reverse flotation system according to claim 1, characterized in that: The method for multi-stage addition of the collector in S3 is as follows: A new reagent addition point is added to the roughing process; when the mass percentage of silica in the system output concentrate is greater than P+a, q... 扫 When the interval adjustment method is insufficient to adjust the percentage of silica in the system output concentrate to the qualified level in a short period of time, a new reagent point is added to the roughing process. With the total amount of collector remaining unchanged, the reagent system is adjusted to a ratio of 7:1:1 for the reagent addition points of the roughing process, the newly added reagent points of the roughing process, and the reagent addition points of the fine process.

4. The method for stabilizing the silica grade of the concentrate output from a hematite reverse flotation system according to claim 1, characterized in that: The method for temporarily storing the slurry in the stirred tank in S4 is as follows: S41. A new concentrate storage mixing tank is built in the flotation system and connected to the concentrate mixing tank. It is equipped with a circulation pump. The concentrate mixing tank and the concentrate storage mixing tank can transfer slurry to each other. The concentrate storage mixing tank can meet the storage capacity of more than 3 hours of slurry output from the hematite reverse flotation system. S42. When the flotation process is extremely abnormal, if the percentage of silica mass in the output concentrate deviates too much from the qualified range and it is expected that the system cannot adjust to the qualified range in time through q-sweep range adjustment, adding concentrate to the flotation feed, and multi-stage addition of collectors, then the concentrate temporary storage mixing tank will be started. The concentrate mixing tank will stop conveying slurry to the filtration workshop and the unqualified slurry will be conveyed to the concentrate temporary storage mixing tank for temporary storage through the circulation pump, so as to buy time for process adjustment. Once the flotation process returns to normal, the unqualified slurry is pumped into the concentrate mixing tank at a low flow rate using a circulating pump. After mixing with the qualified slurry, the mixture is then transported to the filtration workshop.

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